//! A single element of text.
use std::cell::RefCell;
use std::rc::Rc;

use crate::parser::parser_with_context::parser_with_context;
use crate::parser::text::paragraph_end;

use super::nom_context::ContextTree;
use super::nom_context::OrgModeContextNode;
use super::nom_context::OrgModeContextTree;
use super::text::bold_end;
use super::text::bold_start;
use super::text::line_break;
use super::text::link_end;
use super::text::link_start;
use super::text::space;
use super::text::span;
use super::text::symbol;
use super::text::Bold;
use super::text::Link;
use super::text::Res;
use super::text::TextElement;
use nom::branch::alt;
use nom::combinator::eof;
use nom::combinator::map;
use nom::combinator::not;
use nom::combinator::recognize;
use nom::error::ErrorKind;
use nom::error::ParseError;
use nom::error::VerboseError;
use nom::multi::many1;
use nom::multi::many_till;
use nom::sequence::tuple;
use nom::IResult;
use tracing::instrument;
use tracing::trace;

fn context_many_till<
    'r,
    M: for<'s> Fn(&'s str) -> IResult<&'s str, TextElement<'s>, VerboseError<&'s str>>,
    T: for<'s> Fn(&'s str) -> IResult<&'s str, &'s str, VerboseError<&'s str>>,
>(
    context: &'r OrgModeContextNode<'r>,
    many_matcher: M,
    till_matcher: T,
) -> impl for<'s> FnMut(
    &'s str,
) -> IResult<&'s str, (Vec<TextElement<'s>>, &'s str), VerboseError<&'s str>> {
    |i| {
        // todo
        todo!()
    }
}

pub fn document(input: &str) -> Res<&str, Vec<(Vec<TextElement>, &str)>> {
    let initial_context = ContextTree::new();
    let paragraph_parser = parser_with_context!(paragraph);
    let ret = many1(paragraph_parser(&initial_context))(input);
    ret
}

pub fn paragraph<'s, 'r>(
    context: &'r OrgModeContextNode<'r>,
    i: &'s str,
) -> Res<&'s str, (Vec<TextElement<'s>>, &'s str)> {
    // Add a not(eof) check because many_till cannot match a zero-length string
    not(eof)(i)?;
    let paragraph_context = context.with_additional_fail_matcher(&paragraph_end);
    let text_element_parser = parser_with_context!(flat_text_element)(&paragraph_context);
    let ret = context_many_till(&paragraph_context, text_element_parser, paragraph_end)(i);
    // let ret = many_till(text_element_parser, paragraph_end)(i);
    ret
}

fn flat_text_element<'s, 'r>(
    context: &'r OrgModeContextNode<'r>,
    i: &'s str,
) -> Res<&'s str, TextElement<'s>> {
    not(|i| context.match_fail(i))(i)?;

    let bold_matcher = parser_with_context!(flat_bold)(context);
    let link_matcher = parser_with_context!(flat_link)(context);

    alt((
        map(bold_matcher, TextElement::Bold),
        map(link_matcher, TextElement::Link),
        map(span, TextElement::Span),
        map(symbol("*"), TextElement::Symbol),
        map(symbol("["), TextElement::Symbol),
        map(symbol("]"), TextElement::Symbol),
        map(space, TextElement::Space),
        map(line_break, TextElement::LineBreak),
    ))(i)
}

fn recognize_bold_end(input: &str) -> Res<&str, &str> {
    recognize(bold_end)(input)
}

fn flat_bold<'s, 'r>(context: &'r OrgModeContextNode<'r>, i: &'s str) -> Res<&'s str, Bold<'s>> {
    let new_context = context.with_additional_fail_matcher(&recognize_bold_end);
    let text_element_parser = parser_with_context!(flat_text_element)(&new_context);
    let (remaining, captured) = recognize(tuple((
        bold_start,
        many_till(text_element_parser, bold_end),
    )))(i)?;
    let ret = Bold { contents: captured };
    Ok((remaining, ret))
}

fn recognize_link_end(input: &str) -> Res<&str, &str> {
    recognize(link_end)(input)
}

fn flat_link<'s, 'r>(context: &'r OrgModeContextNode<'r>, i: &'s str) -> Res<&'s str, Link<'s>> {
    let new_context = context.with_additional_fail_matcher(&recognize_link_end);
    let text_element_parser = parser_with_context!(flat_text_element)(&new_context);
    let (remaining, captured) = recognize(tuple((
        link_start,
        many_till(text_element_parser, link_end),
    )))(i)?;
    let ret = Link { contents: captured };
    Ok((remaining, ret))
}