use nu_engine::{command_prelude::*, get_eval_block_with_early_return};
use nu_protocol::{engine::CommandType, BlockId};

/// Source a file for environment variables.
#[derive(Clone)]
pub struct Source;

impl Command for Source {
    fn name(&self) -> &str {
        "source"
    }

    fn signature(&self) -> Signature {
        Signature::build("source")
            .input_output_types(vec![(Type::Any, Type::Any)])
            .required(
                "filename",
                SyntaxShape::Filepath,
                "The filepath to the script file to source.",
            )
            .category(Category::Core)
    }

    fn description(&self) -> &str {
        "Runs a script file in the current context."
    }

    fn extra_description(&self) -> &str {
        r#"This command is a parser keyword. For details, check:
  https://www.nushell.sh/book/thinking_in_nu.html"#
    }

    fn command_type(&self) -> CommandType {
        CommandType::Keyword
    }

    fn run(
        &self,
        engine_state: &EngineState,
        stack: &mut Stack,
        call: &Call,
        input: PipelineData,
    ) -> Result<PipelineData, ShellError> {
        // Note: this hidden positional is the block_id that corresponded to the 0th position
        // it is put here by the parser
        let block_id: i64 = call.req_parser_info(engine_state, stack, "block_id")?;
        let block_id = BlockId::new(block_id as usize);
        let block = engine_state.get_block(block_id).clone();

        let eval_block_with_early_return = get_eval_block_with_early_return(engine_state);

        eval_block_with_early_return(engine_state, stack, &block, input)
    }

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Runs foo.nu in the current context",
                example: r#"source foo.nu"#,
                result: None,
            },
            Example {
                description: "Runs foo.nu in current context and call the command defined, suppose foo.nu has content: `def say-hi [] { echo 'Hi!' }`",
                example: r#"source ./foo.nu; say-hi"#,
                result: None,
            },
        ]
    }
}