use nom::branch::alt;
use nom::bytes::complete::is_not;
use nom::bytes::complete::tag_no_case;
use nom::character::complete::anychar;
use nom::character::complete::line_ending;
use nom::character::complete::space0;
use nom::character::complete::space1;
use nom::combinator::consumed;
use nom::combinator::eof;
use nom::combinator::not;
use nom::combinator::opt;
use nom::combinator::peek;
use nom::combinator::recognize;
use nom::combinator::verify;
use nom::multi::many0;
use nom::multi::many_till;
use nom::sequence::preceded;
use nom::sequence::tuple;

use super::org_source::OrgSource;
use super::util::in_section;
use crate::context::parser_with_context;
use crate::context::ContextElement;
use crate::context::ContextMatcher;
use crate::context::ExitClass;
use crate::context::ExitMatcherNode;
use crate::context::RefContext;
use crate::error::CustomError;
use crate::error::MyError;
use crate::error::Res;
use crate::parser::element_parser::element;
use crate::parser::util::blank_line;
use crate::parser::util::exit_matcher_parser;
use crate::parser::util::get_consumed;
use crate::parser::util::start_of_line;
use crate::types::CenterBlock;
use crate::types::Element;
use crate::types::Paragraph;
use crate::types::QuoteBlock;
use crate::types::SetSource;
use crate::types::SpecialBlock;

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
pub(crate) fn greater_block<'b, 'g, 'r, 's>(
    context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
) -> Res<OrgSource<'s>, Element<'s>> {
    start_of_line(input)?;
    let (remaining, _leading_whitespace) = space0(input)?;
    let (remaining, (_begin, name)) = tuple((
        tag_no_case("#+begin_"),
        verify(name, |name: &OrgSource<'_>| {
            match Into::<&str>::into(name).to_lowercase().as_str() {
                "comment" | "example" | "export" | "src" | "verse" => false,
                _ => true,
            }
        }),
    ))(remaining)?;
    let name = Into::<&str>::into(name);
    let (remaining, element) = match name.to_lowercase().as_str() {
        "center" => center_block(context, remaining, input)?,
        "quote" => quote_block(context, remaining, input)?,
        _ => special_block(name)(context, remaining, input)?,
    };
    Ok((remaining, element))
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
fn center_block<'b, 'g, 'r, 's>(
    context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
    original_input: OrgSource<'s>,
) -> Res<OrgSource<'s>, Element<'s>> {
    let (remaining, (source, children)) =
        greater_block_body(context, input, original_input, "center", "center block")?;
    Ok((
        remaining,
        Element::CenterBlock(CenterBlock { source, children }),
    ))
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
fn quote_block<'b, 'g, 'r, 's>(
    context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
    original_input: OrgSource<'s>,
) -> Res<OrgSource<'s>, Element<'s>> {
    let (remaining, (source, children)) =
        greater_block_body(context, input, original_input, "quote", "quote block")?;
    Ok((
        remaining,
        Element::QuoteBlock(QuoteBlock { source, children }),
    ))
}

fn special_block<'s>(
    name: &'s str,
) -> impl for<'b, 'g, 'r> Fn(
    RefContext<'b, 'g, 'r, 's>,
    OrgSource<'s>,
    OrgSource<'s>,
) -> Res<OrgSource<'s>, Element<'s>>
       + 's {
    let context_name = format!("special block {}", name);
    move |context, input, original_input| {
        _special_block(context, input, original_input, name, context_name.as_str())
    }
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
fn _special_block<'c, 'b, 'g, 'r, 's>(
    context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
    original_input: OrgSource<'s>,
    name: &'s str,
    context_name: &'c str,
) -> Res<OrgSource<'s>, Element<'s>> {
    let (remaining, parameters) = opt(tuple((space1, parameters)))(input)?;
    let (remaining, (source, children)) =
        greater_block_body(context, remaining, original_input, name, context_name)?;
    Ok((
        remaining,
        Element::SpecialBlock(SpecialBlock {
            source,
            children,
            name,
            parameters: parameters.map(|(_, parameters)| Into::<&str>::into(parameters)),
        }),
    ))
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
fn greater_block_body<'c, 'b, 'g, 'r, 's>(
    context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
    original_input: OrgSource<'s>,
    name: &'c str,
    context_name: &'c str,
) -> Res<OrgSource<'s>, (&'s str, Vec<Element<'s>>)> {
    if in_section(context, context_name) {
        return Err(nom::Err::Error(CustomError::MyError(MyError(
            "Cannot nest objects of the same element".into(),
        ))));
    }
    let exit_with_name = greater_block_end(name);
    let (remaining, _nl) = tuple((space0, line_ending))(input)?;
    let contexts = [
        ContextElement::ConsumeTrailingWhitespace(true),
        ContextElement::Context(context_name),
        ContextElement::ExitMatcherNode(ExitMatcherNode {
            class: ExitClass::Alpha,
            exit_matcher: &exit_with_name,
        }),
    ];
    let parser_context = context.with_additional_node(&contexts[0]);
    let parser_context = parser_context.with_additional_node(&contexts[1]);
    let parser_context = parser_context.with_additional_node(&contexts[2]);
    let element_matcher = parser_with_context!(element(true))(&parser_context);
    let exit_matcher = parser_with_context!(exit_matcher_parser)(&parser_context);
    not(exit_matcher)(remaining)?;
    let (remaining, leading_blank_lines) = opt(consumed(tuple((
        blank_line,
        many0(preceded(not(exit_matcher), blank_line)),
    ))))(remaining)?;
    let leading_blank_lines =
        leading_blank_lines.map(|(source, (first_line, _remaining_lines))| {
            let mut element = Element::Paragraph(Paragraph::of_text(first_line.into()));
            element.set_source(source.into());
            element
        });
    let (remaining, (mut children, _exit_contents)) =
        many_till(element_matcher, exit_matcher)(remaining)?;
    if let Some(lines) = leading_blank_lines {
        children.insert(0, lines);
    }

    let (remaining, _end) = exit_with_name(&parser_context, remaining)?;

    // Not checking if parent exit matcher is causing exit because the greater_block_end matcher asserts we matched a full greater block

    let source = get_consumed(original_input, remaining);
    Ok((remaining, (Into::<&str>::into(source), children)))
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
fn name<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, OrgSource<'s>> {
    is_not(" \t\r\n")(input)
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
fn parameters<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, OrgSource<'s>> {
    recognize(many_till(anychar, peek(tuple((space0, line_ending)))))(input)
}

fn greater_block_end<'c>(name: &'c str) -> impl ContextMatcher + 'c {
    move |context, input: OrgSource<'_>| _greater_block_end(context, input, name)
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
fn _greater_block_end<'b, 'g, 'r, 's, 'c>(
    _context: RefContext<'b, 'g, 'r, 's>,
    input: OrgSource<'s>,
    name: &'c str,
) -> Res<OrgSource<'s>, OrgSource<'s>> {
    start_of_line(input)?;
    let (remaining, _leading_whitespace) = space0(input)?;
    let (remaining, (_begin, _name, _ws)) = tuple((
        tag_no_case("#+end_"),
        tag_no_case(name),
        alt((eof, line_ending)),
    ))(remaining)?;
    let source = get_consumed(input, remaining);
    Ok((remaining, source))
}