use nu_parser::ParseError;
use nu_parser::*;
use nu_protocol::ast::{Call, PathMember};
use nu_protocol::Span;
use nu_protocol::{
    ast::{Expr, Expression, PipelineElement},
    engine::{Command, EngineState, Stack, StateWorkingSet},
    PipelineData, ShellError, Signature, SyntaxShape,
};

#[cfg(test)]
#[derive(Clone)]
pub struct Let;

#[cfg(test)]
impl Command for Let {
    fn name(&self) -> &str {
        "let"
    }

    fn usage(&self) -> &str {
        "Create a variable and give it a value."
    }

    fn signature(&self) -> nu_protocol::Signature {
        Signature::build("let")
            .required("var_name", SyntaxShape::VarWithOptType, "variable name")
            .required(
                "initial_value",
                SyntaxShape::Keyword(b"=".to_vec(), Box::new(SyntaxShape::MathExpression)),
                "equals sign followed by value",
            )
    }

    fn run(
        &self,
        _engine_state: &EngineState,
        _stack: &mut Stack,
        _call: &Call,
        _input: PipelineData,
    ) -> Result<PipelineData, ShellError> {
        todo!()
    }
}

fn test_int(
    test_tag: &str,     // name of sub-test
    test: &[u8],        // input expression
    expected_val: Expr, // (usually Expr::{Int,String, Float}, not ::BinOp...
    expected_err: Option<&str>,
) // substring in error text
{
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, test, true, &[]);

    if let Some(err_pat) = expected_err {
        if let Some(parse_err) = err {
            let act_err = format!("{:?}", parse_err);
            assert!(
                act_err.contains(err_pat),
                "{test_tag}: expected err to contain {err_pat}, but actual error was {act_err}"
            );
        } else {
            assert!(
                err.is_some(),
                "{test_tag}: expected err containing {err_pat}, but no error returned"
            );
        }
    } else {
        assert!(err.is_none(), "{test_tag}: unexpected error {err:#?}");
        assert_eq!(block.len(), 1, "{test_tag}: result block length > 1");
        let expressions = &block[0];
        assert_eq!(
            expressions.len(),
            1,
            "{test_tag}: got multiple result expressions, expected 1"
        );
        if let PipelineElement::Expression(
            _,
            Expression {
                expr: observed_val, ..
            },
        ) = &expressions[0]
        {
            compare_rhs_binaryOp(test_tag, &expected_val, observed_val);
        }
    }
}

#[allow(non_snake_case)]
fn compare_rhs_binaryOp(
    test_tag: &str,
    expected: &Expr, // the rhs expr we hope to see (::Int, ::Float, not ::B)
    observed: &Expr, // the Expr actually provided: can be ::Int, ::Float, ::String,
                     // or ::BinOp (in which case rhs is checked), or ::Call (in which case cmd is checked)
) {
    match observed {
        Expr::Int(..) | Expr::Float(..) | Expr::String(..) => {
            assert_eq!(
                expected, observed,
                "{test_tag}: Expected: {expected:#?}, observed {observed:#?}"
            );
        }
        Expr::BinaryOp(_, _, e) => {
            let observed_expr = &e.expr;
            // can't pattern match Box<Foo>, but can match the box, then deref in separate statement.
            assert_eq!(
                expected, observed_expr,
                "{test_tag}: Expected: {expected:#?}, observed: {observed:#?}"
            )
        }
        Expr::ExternalCall(e, _, _) => {
            let observed_expr = &e.expr;
            assert_eq!(
                expected, observed_expr,
                "{test_tag}: Expected: {expected:#?}, observed: {observed_expr:#?}"
            )
        }
        _ => {
            panic!("{test_tag}: Unexpected Expr:: variant returned, observed {observed:#?}");
        }
    }
}

#[test]
pub fn multi_test_parse_int() {
    struct Test<'a>(&'a str, &'a [u8], Expr, Option<&'a str>);

    // use test expression of form '0 + x' to force parse() to parse x as numeric.
    // if expression were just 'x', parse() would try other items that would mask the error we're looking for.
    let tests = vec![
        Test("binary literal int", b"0 + 0b0", Expr::Int(0), None),
        Test(
            "binary literal invalid digits",
            b"0 + 0b2",
            Expr::Int(0),
            Some("invalid digits for radix 2"),
        ),
        Test("octal literal int", b"0 + 0o1", Expr::Int(1), None),
        Test(
            "octal literal int invalid digits",
            b"0 + 0o8",
            Expr::Int(0),
            Some("invalid digits for radix 8"),
        ),
        Test(
            "octal literal int truncated",
            b"0 + 0o",
            Expr::Int(0),
            Some("invalid digits for radix 8"),
        ),
        Test("hex literal int", b"0 + 0x2", Expr::Int(2), None),
        Test(
            "hex literal int invalid digits",
            b"0 + 0x0aq",
            Expr::Int(0),
            Some("invalid digits for radix 16"),
        ),
        Test(
            "hex literal with 'e' not mistaken for float",
            b"0 + 0x00e0",
            Expr::Int(0xe0),
            None,
        ),
        // decimal (rad10) literal is anything that starts with
        // optional sign then a digit.
        Test("rad10 literal int", b"0 + 42", Expr::Int(42), None),
        Test(
            "rad10 with leading + sign",
            b"0 + -42",
            Expr::Int(-42),
            None,
        ),
        Test("rad10 with leading - sign", b"0 + +42", Expr::Int(42), None),
        Test(
            "flag char is string, not (invalid) int",
            b"-x",
            Expr::String("-x".into()),
            None,
        ),
        Test(
            "keyword parameter is string",
            b"--exact",
            Expr::String("--exact".into()),
            None,
        ),
        Test(
            "ranges or relative paths not confused for int",
            b"./a/b",
            Expr::String("./a/b".into()),
            None,
        ),
        Test(
            "semver data not confused for int",
            b"1.0.1",
            Expr::String("1.0.1".into()),
            None,
        ),
    ];

    for test in tests {
        test_int(test.0, test.1, test.2, test.3);
    }
}

#[ignore]
#[test]
pub fn multi_test_parse_number() {
    struct Test<'a>(&'a str, &'a [u8], Expr, Option<&'a str>);

    // use test expression of form '0 + x' to force parse() to parse x as numeric.
    // if expression were just 'x', parse() would try other items that would mask the error we're looking for.
    let tests = vec![
        Test("float decimal", b"0 + 43.5", Expr::Float(43.5), None),
        //Test("float with leading + sign", b"0 + +41.7", Expr::Float(-41.7), None),
        Test(
            "float with leading - sign",
            b"0 + -41.7",
            Expr::Float(-41.7),
            None,
        ),
        Test(
            "float scientific notation",
            b"0 + 3e10",
            Expr::Float(3.00e10),
            None,
        ),
        Test(
            "float decimal literal invalid digits",
            b"0 + .3foo",
            Expr::Int(0),
            Some("invalid digits"),
        ),
        Test(
            "float scientific notation literal invalid digits",
            b"0 + 3e0faa",
            Expr::Int(0),
            Some("invalid digits"),
        ),
        Test(
            // odd that error is unsupportedOperation, but it does fail.
            "decimal literal int 2 leading signs",
            b"0 + --9",
            Expr::Int(0),
            Some("UnsupportedOperation"),
        ),
        //Test(
        //    ".<string> should not be taken as float",
        //    b"abc + .foo",
        //    Expr::String("..".into()),
        //    None,
        //),
    ];

    for test in tests {
        test_int(test.0, test.1, test.2, test.3);
    }
}
#[ignore]
#[test]
fn test_parse_any() {
    let test = b"1..10";
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, test, true, &[]);

    match (block, err) {
        (_, Some(e)) => {
            println!("test: {test:?}, error: {e:#?}");
        }
        (b, None) => {
            println!("test: {test:?}, parse: {b:#?}");
        }
    }
}
#[test]
pub fn parse_int() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, b"3", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    assert!(matches!(
        expressions[0],
        PipelineElement::Expression(
            _,
            Expression {
                expr: Expr::Int(3),
                ..
            }
        )
    ))
}

#[test]
pub fn parse_int_with_underscores() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, b"420_69_2023", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    assert!(matches!(
        expressions[0],
        PipelineElement::Expression(
            _,
            Expression {
                expr: Expr::Int(420692023),
                ..
            }
        )
    ))
}

#[test]
pub fn parse_cell_path() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    working_set.add_variable(
        "foo".to_string().into_bytes(),
        Span::test_data(),
        nu_protocol::Type::Record(vec![]),
        false,
    );

    let (block, err) = parse(&mut working_set, None, b"$foo.bar.baz", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);

    // hoo boy this pattern matching is a pain
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        if let Expr::FullCellPath(b) = &expr.expr {
            assert!(matches!(
                b.head,
                Expression {
                    expr: Expr::Var(_),
                    ..
                }
            ));
            if let [a, b] = &b.tail[..] {
                if let PathMember::String { val, optional, .. } = a {
                    assert_eq!(val, "bar");
                    assert_eq!(optional, &false);
                } else {
                    panic!("wrong type")
                }

                if let PathMember::String { val, optional, .. } = b {
                    assert_eq!(val, "baz");
                    assert_eq!(optional, &false);
                } else {
                    panic!("wrong type")
                }
            } else {
                panic!("cell path tail is unexpected")
            }
        } else {
            panic!("Not a cell path");
        }
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_cell_path_optional() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    working_set.add_variable(
        "foo".to_string().into_bytes(),
        Span::test_data(),
        nu_protocol::Type::Record(vec![]),
        false,
    );

    let (block, err) = parse(&mut working_set, None, b"$foo.bar?.baz", true, &[]);

    if let Some(err) = err {
        dbg!(err);
        panic!();
    }

    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);

    // hoo boy this pattern matching is a pain
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        if let Expr::FullCellPath(b) = &expr.expr {
            assert!(matches!(
                b.head,
                Expression {
                    expr: Expr::Var(_),
                    ..
                }
            ));
            if let [a, b] = &b.tail[..] {
                if let PathMember::String { val, optional, .. } = a {
                    assert_eq!(val, "bar");
                    assert_eq!(optional, &true);
                } else {
                    panic!("wrong type")
                }

                if let PathMember::String { val, optional, .. } = b {
                    assert_eq!(val, "baz");
                    assert_eq!(optional, &false);
                } else {
                    panic!("wrong type")
                }
            } else {
                panic!("cell path tail is unexpected")
            }
        } else {
            panic!("Not a cell path");
        }
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_binary_with_hex_format() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, b"0x[13]", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        assert_eq!(expr.expr, Expr::Binary(vec![0x13]))
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_binary_with_incomplete_hex_format() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, b"0x[3]", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        assert_eq!(expr.expr, Expr::Binary(vec![0x03]))
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_binary_with_binary_format() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, b"0b[1010 1000]", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        assert_eq!(expr.expr, Expr::Binary(vec![0b10101000]))
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_binary_with_incomplete_binary_format() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, b"0b[10]", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        assert_eq!(expr.expr, Expr::Binary(vec![0b00000010]))
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_binary_with_octal_format() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, b"0o[250]", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        assert_eq!(expr.expr, Expr::Binary(vec![0o250]))
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_binary_with_incomplete_octal_format() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, b"0o[2]", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        assert_eq!(expr.expr, Expr::Binary(vec![0o2]))
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_binary_with_invalid_octal_format() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let (block, err) = parse(&mut working_set, None, b"0b[90]", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        assert!(!matches!(&expr.expr, Expr::Binary(_)))
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_binary_with_multi_byte_char() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    // found using fuzzing, Rust can panic if you slice into this string
    let contents = b"0x[\xEF\xBF\xBD]";
    let (block, err) = parse(&mut working_set, None, contents, true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);
    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    if let PipelineElement::Expression(_, expr) = &expressions[0] {
        assert!(!matches!(&expr.expr, Expr::Binary(_)))
    } else {
        panic!("Not an expression")
    }
}

#[test]
pub fn parse_call() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let sig = Signature::build("foo").named("--jazz", SyntaxShape::Int, "jazz!!", Some('j'));
    working_set.add_decl(sig.predeclare());

    let (block, err) = parse(&mut working_set, None, b"foo", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);

    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);

    if let PipelineElement::Expression(
        _,
        Expression {
            expr: Expr::Call(call),
            ..
        },
    ) = &expressions[0]
    {
        assert_eq!(call.decl_id, 0);
    }
}

#[test]
pub fn parse_call_missing_flag_arg() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let sig = Signature::build("foo").named("jazz", SyntaxShape::Int, "jazz!!", Some('j'));
    working_set.add_decl(sig.predeclare());

    let (_, err) = parse(&mut working_set, None, b"foo --jazz", true, &[]);
    assert!(matches!(err, Some(ParseError::MissingFlagParam(..))));
}

#[test]
pub fn parse_call_missing_short_flag_arg() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let sig = Signature::build("foo").named("--jazz", SyntaxShape::Int, "jazz!!", Some('j'));
    working_set.add_decl(sig.predeclare());

    let (_, err) = parse(&mut working_set, None, b"foo -j", true, &[]);
    assert!(matches!(err, Some(ParseError::MissingFlagParam(..))));
}

#[test]
pub fn parse_call_too_many_shortflag_args() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let sig = Signature::build("foo")
        .named("--jazz", SyntaxShape::Int, "jazz!!", Some('j'))
        .named("--math", SyntaxShape::Int, "math!!", Some('m'));
    working_set.add_decl(sig.predeclare());
    let (_, err) = parse(&mut working_set, None, b"foo -mj", true, &[]);
    assert!(matches!(
        err,
        Some(ParseError::ShortFlagBatchCantTakeArg(..))
    ));
}

#[test]
pub fn parse_call_unknown_shorthand() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let sig = Signature::build("foo").switch("--jazz", "jazz!!", Some('j'));
    working_set.add_decl(sig.predeclare());
    let (_, err) = parse(&mut working_set, None, b"foo -mj", true, &[]);
    assert!(matches!(err, Some(ParseError::UnknownFlag(..))));
}

#[test]
pub fn parse_call_extra_positional() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let sig = Signature::build("foo").switch("--jazz", "jazz!!", Some('j'));
    working_set.add_decl(sig.predeclare());
    let (_, err) = parse(&mut working_set, None, b"foo -j 100", true, &[]);
    assert!(matches!(err, Some(ParseError::ExtraPositional(..))));
}

#[test]
pub fn parse_call_missing_req_positional() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let sig = Signature::build("foo").required("jazz", SyntaxShape::Int, "jazz!!");
    working_set.add_decl(sig.predeclare());
    let (_, err) = parse(&mut working_set, None, b"foo", true, &[]);
    assert!(matches!(err, Some(ParseError::MissingPositional(..))));
}

#[test]
pub fn parse_call_missing_req_flag() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);

    let sig = Signature::build("foo").required_named("--jazz", SyntaxShape::Int, "jazz!!", None);
    working_set.add_decl(sig.predeclare());
    let (_, err) = parse(&mut working_set, None, b"foo", true, &[]);
    assert!(matches!(err, Some(ParseError::MissingRequiredFlag(..))));
}

#[test]
fn test_nothing_comparison_eq() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);
    let (block, err) = parse(&mut working_set, None, b"2 == null", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);

    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    assert!(matches!(
        &expressions[0],
        PipelineElement::Expression(
            _,
            Expression {
                expr: Expr::BinaryOp(..),
                ..
            }
        )
    ))
}

#[test]
fn test_nothing_comparison_neq() {
    let engine_state = EngineState::new();
    let mut working_set = StateWorkingSet::new(&engine_state);
    let (block, err) = parse(&mut working_set, None, b"2 != null", true, &[]);

    assert!(err.is_none());
    assert_eq!(block.len(), 1);

    let expressions = &block[0];
    assert_eq!(expressions.len(), 1);
    assert!(matches!(
        &expressions[0],
        PipelineElement::Expression(
            _,
            Expression {
                expr: Expr::BinaryOp(..),
                ..
            }
        )
    ))
}

mod string {
    use super::*;

    #[test]
    pub fn parse_string() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (block, err) = parse(&mut working_set, None, b"\"hello nushell\"", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);
        let expressions = &block[0];
        assert_eq!(expressions.len(), 1);
        if let PipelineElement::Expression(_, expr) = &expressions[0] {
            assert_eq!(expr.expr, Expr::String("hello nushell".to_string()))
        } else {
            panic!("Not an expression")
        }
    }

    mod interpolation {
        use nu_protocol::Span;

        use super::*;

        #[test]
        pub fn parse_string_interpolation() {
            let engine_state = EngineState::new();
            let mut working_set = StateWorkingSet::new(&engine_state);

            let (block, err) = parse(&mut working_set, None, b"$\"hello (39 + 3)\"", true, &[]);

            assert!(err.is_none());
            assert_eq!(block.len(), 1);

            let expressions = &block[0];
            assert_eq!(expressions.len(), 1);

            if let PipelineElement::Expression(_, expr) = &expressions[0] {
                let subexprs: Vec<&Expr> = match expr {
                    Expression {
                        expr: Expr::StringInterpolation(expressions),
                        ..
                    } => expressions.iter().map(|e| &e.expr).collect(),
                    _ => panic!("Expected an `Expr::StringInterpolation`"),
                };

                assert_eq!(subexprs.len(), 2);

                assert_eq!(subexprs[0], &Expr::String("hello ".to_string()));

                assert!(matches!(subexprs[1], &Expr::FullCellPath(..)));
            } else {
                panic!("Not an expression")
            }
        }

        #[test]
        pub fn parse_string_interpolation_escaped_parenthesis() {
            let engine_state = EngineState::new();
            let mut working_set = StateWorkingSet::new(&engine_state);

            let (block, err) = parse(&mut working_set, None, b"$\"hello \\(39 + 3)\"", true, &[]);

            assert!(err.is_none());

            assert_eq!(block.len(), 1);
            let expressions = &block[0];

            assert_eq!(expressions.len(), 1);

            if let PipelineElement::Expression(_, expr) = &expressions[0] {
                let subexprs: Vec<&Expr> = match expr {
                    Expression {
                        expr: Expr::StringInterpolation(expressions),
                        ..
                    } => expressions.iter().map(|e| &e.expr).collect(),
                    _ => panic!("Expected an `Expr::StringInterpolation`"),
                };

                assert_eq!(subexprs.len(), 1);

                assert_eq!(subexprs[0], &Expr::String("hello (39 + 3)".to_string()));
            } else {
                panic!("Not an expression")
            }
        }

        #[test]
        pub fn parse_string_interpolation_escaped_backslash_before_parenthesis() {
            let engine_state = EngineState::new();
            let mut working_set = StateWorkingSet::new(&engine_state);

            let (block, err) = parse(
                &mut working_set,
                None,
                b"$\"hello \\\\(39 + 3)\"",
                true,
                &[],
            );

            assert!(err.is_none());

            assert_eq!(block.len(), 1);
            let expressions = &block[0];

            assert_eq!(expressions.len(), 1);

            if let PipelineElement::Expression(_, expr) = &expressions[0] {
                let subexprs: Vec<&Expr> = match expr {
                    Expression {
                        expr: Expr::StringInterpolation(expressions),
                        ..
                    } => expressions.iter().map(|e| &e.expr).collect(),
                    _ => panic!("Expected an `Expr::StringInterpolation`"),
                };

                assert_eq!(subexprs.len(), 2);

                assert_eq!(subexprs[0], &Expr::String("hello \\".to_string()));

                assert!(matches!(subexprs[1], &Expr::FullCellPath(..)));
            } else {
                panic!("Not an expression")
            }
        }

        #[test]
        pub fn parse_string_interpolation_backslash_count_reset_by_expression() {
            let engine_state = EngineState::new();
            let mut working_set = StateWorkingSet::new(&engine_state);

            let (block, err) = parse(
                &mut working_set,
                None,
                b"$\"\\(1 + 3)\\(7 - 5)\"",
                true,
                &[],
            );

            assert!(err.is_none());

            assert_eq!(block.len(), 1);
            let expressions = &block[0];

            assert_eq!(expressions.len(), 1);

            if let PipelineElement::Expression(_, expr) = &expressions[0] {
                let subexprs: Vec<&Expr> = match expr {
                    Expression {
                        expr: Expr::StringInterpolation(expressions),
                        ..
                    } => expressions.iter().map(|e| &e.expr).collect(),
                    _ => panic!("Expected an `Expr::StringInterpolation`"),
                };

                assert_eq!(subexprs.len(), 1);
                assert_eq!(subexprs[0], &Expr::String("(1 + 3)(7 - 5)".to_string()));
            } else {
                panic!("Not an expression")
            }
        }

        #[test]
        pub fn parse_nested_expressions() {
            let engine_state = EngineState::new();
            let mut working_set = StateWorkingSet::new(&engine_state);

            working_set.add_variable(
                "foo".to_string().into_bytes(),
                Span::new(0, 0),
                nu_protocol::Type::CellPath,
                false,
            );

            let (_block, err) = parse(
                &mut working_set,
                None,
                br#"
                $"(($foo))"
                "#,
                true,
                &[],
            );

            assert!(err.is_none());
        }

        #[test]
        pub fn parse_path_expression() {
            let engine_state = EngineState::new();
            let mut working_set = StateWorkingSet::new(&engine_state);

            working_set.add_variable(
                "foo".to_string().into_bytes(),
                Span::new(0, 0),
                nu_protocol::Type::CellPath,
                false,
            );

            let (_block, err) = parse(
                &mut working_set,
                None,
                br#"
                $"Hello ($foo.bar)"
                "#,
                true,
                &[],
            );

            assert!(err.is_none());
        }
    }
}

mod range {
    use super::*;
    use nu_protocol::ast::{RangeInclusion, RangeOperator};

    #[test]
    fn parse_inclusive_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (block, err) = parse(&mut working_set, None, b"0..10", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        Some(_),
                        None,
                        Some(_),
                        RangeOperator {
                            inclusion: RangeInclusion::Inclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn parse_exclusive_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (block, err) = parse(&mut working_set, None, b"0..<10", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        Some(_),
                        None,
                        Some(_),
                        RangeOperator {
                            inclusion: RangeInclusion::RightExclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn parse_reverse_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (block, err) = parse(&mut working_set, None, b"10..0", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        Some(_),
                        None,
                        Some(_),
                        RangeOperator {
                            inclusion: RangeInclusion::Inclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn parse_subexpression_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (block, err) = parse(&mut working_set, None, b"(3 - 3)..<(8 + 2)", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        Some(_),
                        None,
                        Some(_),
                        RangeOperator {
                            inclusion: RangeInclusion::RightExclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn parse_variable_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        working_set.add_decl(Box::new(Let));

        let (block, err) = parse(&mut working_set, None, b"let a = 2; $a..10", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 2);

        let expressions = &block[1];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        Some(_),
                        None,
                        Some(_),
                        RangeOperator {
                            inclusion: RangeInclusion::Inclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn parse_subexpression_variable_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        working_set.add_decl(Box::new(Let));

        let (block, err) = parse(
            &mut working_set,
            None,
            b"let a = 2; $a..<($a + 10)",
            true,
            &[],
        );

        assert!(err.is_none());
        assert_eq!(block.len(), 2);

        let expressions = &block[1];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        Some(_),
                        None,
                        Some(_),
                        RangeOperator {
                            inclusion: RangeInclusion::RightExclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn parse_right_unbounded_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (block, err) = parse(&mut working_set, None, b"0..", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        Some(_),
                        None,
                        None,
                        RangeOperator {
                            inclusion: RangeInclusion::Inclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn parse_left_unbounded_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (block, err) = parse(&mut working_set, None, b"..10", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        None,
                        None,
                        Some(_),
                        RangeOperator {
                            inclusion: RangeInclusion::Inclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn parse_negative_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (block, err) = parse(&mut working_set, None, b"-10..-3", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        Some(_),
                        None,
                        Some(_),
                        RangeOperator {
                            inclusion: RangeInclusion::Inclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn parse_float_range() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (block, err) = parse(&mut working_set, None, b"2.0..4.0..10.0", true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 1);
        assert!(matches!(
            expressions[0],
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Range(
                        Some(_),
                        Some(_),
                        Some(_),
                        RangeOperator {
                            inclusion: RangeInclusion::Inclusive,
                            ..
                        }
                    ),
                    ..
                }
            )
        ))
    }

    #[test]
    fn bad_parse_does_crash() {
        let engine_state = EngineState::new();
        let mut working_set = StateWorkingSet::new(&engine_state);

        let (_, err) = parse(&mut working_set, None, b"(0)..\"a\"", true, &[]);

        assert!(err.is_some());
    }
}

#[cfg(test)]
mod input_types {
    use super::*;
    use nu_protocol::ast::Call;
    use nu_protocol::{ast::Argument, Category, PipelineData, ShellError, Type};

    #[derive(Clone)]
    pub struct LsTest;

    impl Command for LsTest {
        fn name(&self) -> &str {
            "ls"
        }

        fn usage(&self) -> &str {
            "Mock ls command."
        }

        fn signature(&self) -> nu_protocol::Signature {
            Signature::build(self.name()).category(Category::Default)
        }

        fn run(
            &self,
            _engine_state: &EngineState,
            _stack: &mut Stack,
            _call: &Call,
            _input: PipelineData,
        ) -> Result<PipelineData, ShellError> {
            todo!()
        }
    }

    #[derive(Clone)]
    pub struct GroupBy;

    impl Command for GroupBy {
        fn name(&self) -> &str {
            "group-by"
        }

        fn usage(&self) -> &str {
            "Mock group-by command."
        }

        fn signature(&self) -> nu_protocol::Signature {
            Signature::build(self.name())
                .required("column", SyntaxShape::String, "column name")
                .category(Category::Default)
        }

        fn run(
            &self,
            _engine_state: &EngineState,
            _stack: &mut Stack,
            _call: &Call,
            _input: PipelineData,
        ) -> Result<PipelineData, ShellError> {
            todo!()
        }
    }

    #[derive(Clone)]
    pub struct ToCustom;

    impl Command for ToCustom {
        fn name(&self) -> &str {
            "to-custom"
        }

        fn usage(&self) -> &str {
            "Mock converter command."
        }

        fn signature(&self) -> nu_protocol::Signature {
            Signature::build(self.name())
                .input_type(Type::Any)
                .output_type(Type::Custom("custom".into()))
                .category(Category::Custom("custom".into()))
        }

        fn run(
            &self,
            _engine_state: &EngineState,
            _stack: &mut Stack,
            _call: &Call,
            _input: PipelineData,
        ) -> Result<PipelineData, ShellError> {
            todo!()
        }
    }

    #[derive(Clone)]
    pub struct GroupByCustom;

    impl Command for GroupByCustom {
        fn name(&self) -> &str {
            "group-by"
        }

        fn usage(&self) -> &str {
            "Mock custom group-by command."
        }

        fn signature(&self) -> nu_protocol::Signature {
            Signature::build(self.name())
                .required("column", SyntaxShape::String, "column name")
                .required("other", SyntaxShape::String, "other value")
                .input_type(Type::Custom("custom".into()))
                .output_type(Type::Custom("custom".into()))
                .category(Category::Custom("custom".into()))
        }

        fn run(
            &self,
            _engine_state: &EngineState,
            _stack: &mut Stack,
            _call: &Call,
            _input: PipelineData,
        ) -> Result<PipelineData, ShellError> {
            todo!()
        }
    }

    #[derive(Clone)]
    pub struct AggCustom;

    impl Command for AggCustom {
        fn name(&self) -> &str {
            "agg"
        }

        fn usage(&self) -> &str {
            "Mock custom agg command."
        }

        fn signature(&self) -> nu_protocol::Signature {
            Signature::build(self.name())
                .required("operation", SyntaxShape::String, "operation")
                .input_type(Type::Custom("custom".into()))
                .category(Category::Custom("custom".into()))
        }

        fn run(
            &self,
            _engine_state: &EngineState,
            _stack: &mut Stack,
            _call: &Call,
            _input: PipelineData,
        ) -> Result<PipelineData, ShellError> {
            todo!()
        }
    }

    #[derive(Clone)]
    pub struct AggMin;

    impl Command for AggMin {
        fn name(&self) -> &str {
            "min"
        }

        fn usage(&self) -> &str {
            "Mock custom min command."
        }

        fn signature(&self) -> nu_protocol::Signature {
            Signature::build(self.name()).category(Category::Custom("custom".into()))
        }

        fn run(
            &self,
            _engine_state: &EngineState,
            _stack: &mut Stack,
            _call: &Call,
            _input: PipelineData,
        ) -> Result<PipelineData, ShellError> {
            todo!()
        }
    }

    #[derive(Clone)]
    pub struct WithColumn;

    impl Command for WithColumn {
        fn name(&self) -> &str {
            "with-column"
        }

        fn usage(&self) -> &str {
            "Mock custom with-column command."
        }

        fn signature(&self) -> nu_protocol::Signature {
            Signature::build(self.name())
                .rest("operation", SyntaxShape::Any, "operation")
                .input_type(Type::Custom("custom".into()))
                .output_type(Type::Custom("custom".into()))
                .category(Category::Custom("custom".into()))
        }

        fn run(
            &self,
            _engine_state: &EngineState,
            _stack: &mut Stack,
            _call: &Call,
            _input: PipelineData,
        ) -> Result<PipelineData, ShellError> {
            todo!()
        }
    }

    #[derive(Clone)]
    pub struct Collect;

    impl Command for Collect {
        fn name(&self) -> &str {
            "collect"
        }

        fn usage(&self) -> &str {
            "Mock custom collect command."
        }

        fn signature(&self) -> nu_protocol::Signature {
            Signature::build(self.name())
                .input_type(Type::Custom("custom".into()))
                .output_type(Type::Custom("custom".into()))
                .category(Category::Custom("custom".into()))
        }

        fn run(
            &self,
            _engine_state: &EngineState,
            _stack: &mut Stack,
            _call: &Call,
            _input: PipelineData,
        ) -> Result<PipelineData, ShellError> {
            todo!()
        }
    }

    #[derive(Clone)]
    pub struct IfMocked;

    impl Command for IfMocked {
        fn name(&self) -> &str {
            "if"
        }

        fn usage(&self) -> &str {
            "Mock if command."
        }

        fn signature(&self) -> nu_protocol::Signature {
            Signature::build("if")
                .required("cond", SyntaxShape::MathExpression, "condition to check")
                .required(
                    "then_block",
                    SyntaxShape::Block,
                    "block to run if check succeeds",
                )
                .optional(
                    "else_expression",
                    SyntaxShape::Keyword(
                        b"else".to_vec(),
                        Box::new(SyntaxShape::OneOf(vec![
                            SyntaxShape::Block,
                            SyntaxShape::Expression,
                        ])),
                    ),
                    "expression or block to run if check fails",
                )
                .category(Category::Core)
        }

        fn run(
            &self,
            _engine_state: &EngineState,
            _stack: &mut Stack,
            _call: &Call,
            _input: PipelineData,
        ) -> Result<PipelineData, ShellError> {
            todo!()
        }
    }

    fn add_declarations(engine_state: &mut EngineState) {
        let delta = {
            let mut working_set = StateWorkingSet::new(engine_state);
            working_set.add_decl(Box::new(Let));
            working_set.add_decl(Box::new(AggCustom));
            working_set.add_decl(Box::new(GroupByCustom));
            working_set.add_decl(Box::new(GroupBy));
            working_set.add_decl(Box::new(LsTest));
            working_set.add_decl(Box::new(ToCustom));
            working_set.add_decl(Box::new(AggMin));
            working_set.add_decl(Box::new(Collect));
            working_set.add_decl(Box::new(WithColumn));
            working_set.add_decl(Box::new(IfMocked));

            working_set.render()
        };

        engine_state
            .merge_delta(delta)
            .expect("Error merging delta");
    }

    #[test]
    fn call_types_test() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let mut working_set = StateWorkingSet::new(&engine_state);
        let input = r#"ls | to-custom | group-by name other"#;

        let (block, err) = parse(&mut working_set, None, input.as_bytes(), true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 3);

        match &expressions[0] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set
                    .find_decl(b"ls", &Type::Any)
                    .expect("Error merging delta");
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }

        match &expressions[1] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set.find_decl(b"to-custom", &Type::Any).unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }

        match &expressions[2] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set
                    .find_decl(b"group-by", &Type::Custom("custom".into()))
                    .unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }
    }

    #[test]
    fn storing_variable_test() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let mut working_set = StateWorkingSet::new(&engine_state);
        let input =
            r#"let a = (ls | to-custom | group-by name other); let b = (1+3); $a | agg sum"#;

        let (block, err) = parse(&mut working_set, None, input.as_bytes(), true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 3);

        let expressions = &block[2];
        match &expressions[1] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set
                    .find_decl(b"agg", &Type::Custom("custom".into()))
                    .unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }
    }

    #[test]
    fn stored_variable_operation_test() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let mut working_set = StateWorkingSet::new(&engine_state);
        let input = r#"let a = (ls | to-custom | group-by name other); ($a + $a) | agg sum"#;

        let (block, err) = parse(&mut working_set, None, input.as_bytes(), true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 2);

        let expressions = &block[1];
        match &expressions[1] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set
                    .find_decl(b"agg", &Type::Custom("custom".into()))
                    .unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }
    }

    #[test]
    fn multiple_stored_variable_test() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let mut working_set = StateWorkingSet::new(&engine_state);
        let input = r#"
        let a = (ls | to-custom | group-by name other); [1 2 3] | to-custom; [1 2 3] | to-custom"#;

        let (block, err) = parse(&mut working_set, None, input.as_bytes(), true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 3);

        let expressions = &block[1];
        match &expressions[1] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set.find_decl(b"to-custom", &Type::Any).unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }

        let expressions = &block[2];
        match &expressions[1] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set.find_decl(b"to-custom", &Type::Any).unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }
    }

    #[test]
    fn call_non_custom_types_test() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let mut working_set = StateWorkingSet::new(&engine_state);
        let input = r#"ls | group-by name"#;

        let (block, err) = parse(&mut working_set, None, input.as_bytes(), true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        assert_eq!(expressions.len(), 2);

        match &expressions[0] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set.find_decl(b"ls", &Type::Any).unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }

        match &expressions[1] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set.find_decl(b"group-by", &Type::Any).unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }
    }

    #[test]
    fn nested_operations_test() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let (block, delta) = {
            let mut working_set = StateWorkingSet::new(&engine_state);
            let input = r#"ls | to-custom | group-by name other | agg ("b" | min)"#;
            let (block, _) = parse(&mut working_set, None, input.as_bytes(), true, &[]);

            (block, working_set.render())
        };

        engine_state.merge_delta(delta).unwrap();

        let expressions = &block[0];
        match &expressions[3] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let arg = &call.arguments[0];
                match arg {
                    Argument::Positional(a) => match &a.expr {
                        Expr::FullCellPath(path) => match &path.head.expr {
                            Expr::Subexpression(id) => {
                                let block = engine_state.get_block(*id);

                                let expressions = &block[0];
                                assert_eq!(expressions.len(), 2);

                                match &expressions[1] {
                                    PipelineElement::Expression(
                                        _,
                                        Expression {
                                            expr: Expr::Call(call),
                                            ..
                                        },
                                    ) => {
                                        let working_set = StateWorkingSet::new(&engine_state);
                                        let expected_id =
                                            working_set.find_decl(b"min", &Type::Any).unwrap();
                                        assert_eq!(call.decl_id, expected_id)
                                    }
                                    _ => panic!("Expected expression Call not found"),
                                }
                            }
                            _ => panic!("Expected Subexpression not found"),
                        },
                        _ => panic!("Expected FullCellPath not found"),
                    },
                    _ => panic!("Expected Argument Positional not found"),
                }
            }
            _ => panic!("Expected expression Call not found"),
        }
    }

    #[test]
    fn call_with_list_test() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let mut working_set = StateWorkingSet::new(&engine_state);
        let input = r#"[[a b]; [1 2] [3 4]] | to-custom | with-column [ ("a" | min) ("b" | min) ] | collect"#;

        let (block, err) = parse(&mut working_set, None, input.as_bytes(), true, &[]);

        assert!(err.is_none());
        assert_eq!(block.len(), 1);

        let expressions = &block[0];
        match &expressions[2] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set
                    .find_decl(b"with-column", &Type::Custom("custom".into()))
                    .unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }

        match &expressions[3] {
            PipelineElement::Expression(
                _,
                Expression {
                    expr: Expr::Call(call),
                    ..
                },
            ) => {
                let expected_id = working_set
                    .find_decl(b"collect", &Type::Custom("custom".into()))
                    .unwrap();
                assert_eq!(call.decl_id, expected_id)
            }
            _ => panic!("Expected expression Call not found"),
        }
    }

    #[test]
    fn operations_within_blocks_test() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let mut working_set = StateWorkingSet::new(&engine_state);
        let inputs = vec![
            r#"let a = 'b'; ($a == 'b') or ($a == 'b')"#,
            r#"let a = 'b'; ($a == 'b') or ($a == 'b') and ($a == 'b')"#,
            r#"let a = 1; ($a == 1) or ($a == 2) and ($a == 3)"#,
            r#"let a = 'b'; if ($a == 'b') or ($a == 'b') { true } else { false }"#,
            r#"let a = 1; if ($a == 1) or ($a > 0) { true } else { false }"#,
        ];

        for input in inputs {
            let (block, err) = parse(&mut working_set, None, input.as_bytes(), true, &[]);

            assert!(err.is_none(), "testing: {input}");
            assert_eq!(block.len(), 2, "testing: {input}");
        }
    }

    #[test]
    fn else_errors_correctly() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let mut working_set = StateWorkingSet::new(&engine_state);
        let (_, err) = parse(
            &mut working_set,
            None,
            b"if false { 'a' } else { $foo }",
            true,
            &[],
        );

        let err = err.unwrap();

        assert!(matches!(err, ParseError::VariableNotFound(_)));
    }

    #[test]
    fn else_if_errors_correctly() {
        let mut engine_state = EngineState::new();
        add_declarations(&mut engine_state);

        let mut working_set = StateWorkingSet::new(&engine_state);
        let (_, err) = parse(
            &mut working_set,
            None,
            b"if false { 'a' } else $foo { 'b' }",
            true,
            &[],
        );

        let err = err.unwrap();

        assert!(matches!(err, ParseError::VariableNotFound(_)));
    }
}