use crate::{
    lex::tokens::LiteCommand,
    parse::{classify_block, util::trim_quotes},
};

use indexmap::IndexMap;
use nu_errors::ParseError;
use nu_protocol::hir::Block;
use nu_source::{HasSpan, SpannedItem};

//use crate::errors::{ParseError, ParseResult};
use crate::lex::lexer::{block, lex};

use crate::ParserScope;

use self::param_flag_list::parse_signature;

mod param_flag_list;

pub(crate) fn parse_definition(call: &LiteCommand, scope: &dyn ParserScope) -> Option<ParseError> {
    // A this point, we've already handled the prototype and put it into scope;
    // So our main goal here is to parse the block now that the names and
    // prototypes of adjacent commands are also available

    if call.parts.len() == 4 {
        if call.parts.len() != 4 {
            return Some(ParseError::mismatch("definition", call.parts[0].clone()));
        }

        if call.parts[0].item != "def" {
            return Some(ParseError::mismatch("definition", call.parts[0].clone()));
        }

        let name = trim_quotes(&call.parts[1].item);
        let (mut signature, err) = parse_signature(&name, &call.parts[2]);

        //Add commands comments to signature usage
        signature.usage = call.comments_joined();

        if err.is_some() {
            return err;
        };

        let mut chars = call.parts[3].chars();
        match (chars.next(), chars.next_back()) {
            (Some('{'), Some('}')) => {
                // We have a literal block
                let string: String = chars.collect();

                scope.enter_scope();

                let (tokens, err) = lex(&string, call.parts[3].span.start() + 1);
                if err.is_some() {
                    return err;
                };
                let (lite_block, err) = block(tokens);
                if err.is_some() {
                    return err;
                };

                let (mut block, err) = classify_block(&lite_block, scope);
                scope.exit_scope();

                block.params = signature;
                block.params.name = name;

                scope.add_definition(block);

                err
            }
            _ => Some(ParseError::mismatch("body", call.parts[3].clone())),
        }
    } else {
        Some(ParseError::internal_error(
            "need a block".to_string().spanned(call.span()),
        ))
    }
}

pub(crate) fn parse_definition_prototype(
    call: &LiteCommand,
    scope: &dyn ParserScope,
) -> Option<ParseError> {
    let mut err = None;

    if call.parts.len() != 4 {
        return Some(ParseError::mismatch("definition", call.parts[0].clone()));
    }

    if call.parts[0].item != "def" {
        return Some(ParseError::mismatch("definition", call.parts[0].clone()));
    }

    let name = trim_quotes(&call.parts[1].item);
    let (signature, error) = parse_signature(&name, &call.parts[2]);
    if err.is_none() {
        err = error;
    }

    scope.add_definition(Block::new(signature, vec![], IndexMap::new(), call.span()));

    err
}