use nom::branch::alt;
use nom::bytes::complete::escaped;
use nom::bytes::complete::tag;
use nom::bytes::complete::take_till1;
use nom::character::complete::one_of;
use nom::combinator::verify;
use nom::multi::many_till;

use super::object_parser::regular_link_description_object_set;
use super::org_source::OrgSource;
use super::util::exit_matcher_parser;
use super::util::get_consumed;
use super::util::maybe_consume_object_trailing_whitespace_if_not_exiting;
use crate::context::parser_with_context;
use crate::context::ContextElement;
use crate::context::ExitClass;
use crate::context::ExitMatcherNode;
use crate::context::RefContext;
use crate::error::Res;
use crate::types::Object;
use crate::types::RegularLink;

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
pub fn regular_link<'b, 'g, 'r, 's>(
    context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
) -> Res<OrgSource<'s>, RegularLink<'s>> {
    alt((
        parser_with_context!(regular_link_without_description)(context),
        parser_with_context!(regular_link_with_description)(context),
    ))(input)
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
pub fn regular_link_without_description<'b, 'g, 'r, 's>(
    context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
) -> Res<OrgSource<'s>, RegularLink<'s>> {
    let (remaining, _opening_bracket) = tag("[[")(input)?;
    let (remaining, _path) = pathreg(context, remaining)?;
    let (remaining, _closing_bracket) = tag("]]")(remaining)?;
    let (remaining, _trailing_whitespace) =
        maybe_consume_object_trailing_whitespace_if_not_exiting(context, remaining)?;
    let source = get_consumed(input, remaining);
    Ok((
        remaining,
        RegularLink {
            source: source.into(),
        },
    ))
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
pub fn regular_link_with_description<'b, 'g, 'r, 's>(
    context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
) -> Res<OrgSource<'s>, RegularLink<'s>> {
    let (remaining, _opening_bracket) = tag("[[")(input)?;
    let (remaining, _path) = pathreg(context, remaining)?;
    let (remaining, _closing_bracket) = tag("][")(remaining)?;
    let (remaining, _description) = description(context, remaining)?;
    let (remaining, _closing_bracket) = tag("]]")(remaining)?;
    let (remaining, _trailing_whitespace) =
        maybe_consume_object_trailing_whitespace_if_not_exiting(context, remaining)?;
    let source = get_consumed(input, remaining);
    Ok((
        remaining,
        RegularLink {
            source: source.into(),
        },
    ))
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
pub fn pathreg<'b, 'g, 'r, 's>(
    _context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
) -> Res<OrgSource<'s>, OrgSource<'s>> {
    let (remaining, path) = escaped(
        take_till1(|c| match c {
            '\\' | ']' => true,
            _ => false,
        }),
        '\\',
        one_of(r#"]"#),
    )(input)?;
    Ok((remaining, path))
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
pub fn description<'b, 'g, 'r, 's>(
    context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
) -> Res<OrgSource<'s>, Vec<Object<'s>>> {
    let parser_context = ContextElement::ExitMatcherNode(ExitMatcherNode {
        class: ExitClass::Beta,
        exit_matcher: &description_end,
    });
    let parser_context = context.with_additional_node(&parser_context);
    let (remaining, (children, _exit_contents)) = verify(
        many_till(
            parser_with_context!(regular_link_description_object_set)(&parser_context),
            parser_with_context!(exit_matcher_parser)(&parser_context),
        ),
        |(children, _exit_contents)| !children.is_empty(),
    )(input)?;

    Ok((remaining, children))
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
fn description_end<'b, 'g, 'r, 's>(
    _context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
) -> Res<OrgSource<'s>, OrgSource<'s>> {
    tag("]]")(input)
}