use nom::bytes::complete::tag;
use nom::character::complete::anychar;
use nom::combinator::not;
use nom::combinator::opt;
use nom::combinator::peek;
use nom::combinator::verify;
use nom::multi::many0;
use nom::multi::separated_list0;

use super::Context;
use crate::error::Res;
use crate::parser::object::OrgMacro;
use crate::parser::parser_with_context::parser_with_context;
use crate::parser::util::exit_matcher_parser;
use crate::parser::util::get_consumed;

#[tracing::instrument(ret, level = "debug")]
pub fn org_macro<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, OrgMacro<'s>> {
    let (remaining, _) = tag("{{{")(input)?;
    let (remaining, macro_name) = org_macro_name(context, remaining)?;
    let (remaining, macro_args) = opt(parser_with_context!(org_macro_args)(context))(remaining)?;
    let (remaining, _) = tag("}}}")(remaining)?;

    let source = get_consumed(input, remaining);
    Ok((
        remaining,
        OrgMacro {
            source,
            macro_name,
            macro_args: macro_args.unwrap_or_else(|| Vec::with_capacity(0)),
        },
    ))
}

#[tracing::instrument(ret, level = "debug")]
fn org_macro_name<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
    let (remaining, _) = verify(anychar, |c| c.is_alphabetic())(input)?;
    let (remaining, _) = many0(verify(anychar, |c| {
        c.is_alphanumeric() || *c == '-' || *c == '_'
    }))(remaining)?;
    let source = get_consumed(input, remaining);
    Ok((remaining, source))
}

#[tracing::instrument(ret, level = "debug")]
fn org_macro_args<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, Vec<&'s str>> {
    let (remaining, _) = tag("(")(input)?;
    let (remaining, args) =
        separated_list0(tag(","), parser_with_context!(org_macro_arg)(context))(remaining)?;
    let (remaining, _) = tag(")")(remaining)?;

    Ok((remaining, args))
}

#[tracing::instrument(ret, level = "debug")]
fn org_macro_arg<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
    let mut remaining = input;
    let mut escaping: bool = false;
    loop {
        not(parser_with_context!(exit_matcher_parser)(context))(remaining)?;
        not(peek(tag("}}}")))(remaining)?;
        let (new_remaining, next_char) = anychar(remaining)?;
        if escaping {
            remaining = new_remaining;
            escaping = false;
            continue;
        }
        if next_char == '\\' {
            escaping = true;
        }
        if next_char == ',' || next_char == ')' {
            break;
        }
        remaining = new_remaining;
    }
    let source = get_consumed(input, remaining);
    Ok((remaining, source))
}