use mlua::{Function, Lua};
use regex::Regex;
use serde::{Deserialize, Serialize};
use crate::parser::{parser::Parser, rule::RegexRule, source::{Source, Token}, util};
use ariadne::{Report, Fmt, Label, ReportKind};
use crate::{compiler::compiler::{Compiler, Target}, document::{document::Document, element::{ElemKind, Element}}};
use std::{ops::Range, rc::Rc};

#[derive(Debug)]
pub struct Link {
    location: Token,
	name: String, // Link name
	url: String, // Link url
}

impl Link
{
    pub fn new(location: Token, name: String, url: String) -> Self {
        Self { location: location, name, url }
    }
}

impl Element for Link
{
    fn location(&self) -> &Token { &self.location }
    fn kind(&self) -> ElemKind { ElemKind::Inline }
    fn element_name(&self) -> &'static str { "Link" }
    fn to_string(&self) -> String { format!("{self:#?}") }
    fn compile(&self, compiler: &Compiler, _document: &Document) -> Result<String, String> {
        match compiler.target()
        {
            Target::HTML => {
                Ok(format!("<a href=\"{}\">{}</a>",
                    compiler.sanitize(self.url.as_str()),
                    compiler.sanitize(self.name.as_str()),
                ))
            },
            Target::LATEX => {
                Ok(format!("\\href{{{}}}{{{}}}",
                    compiler.sanitize(self.url.as_str()),
                    compiler.sanitize(self.name.as_str()),
                ))
            },
        }
    }
}

pub struct LinkRule {
	re: [Regex; 1],
}

impl LinkRule {
	pub fn new() -> Self {
		Self { re: [Regex::new(r"(?:^|\n)```(.*?)(?:,(.*))?\n((?:\\.|[^\[\]\\])*?)```").unwrap()] }
	}
}

impl RegexRule for LinkRule {
	fn name(&self) -> &'static str { "Link" }

	fn regexes(&self) -> &[Regex] { &self.re }

	fn on_regex_match(&self, _: usize, parser: &dyn Parser, document: &Document, token: Token, matches: regex::Captures) -> Vec<Report<'_, (Rc<dyn Source>, Range<usize>)>>
	{
		let mut result = vec![];
        let link_name = match matches.get(1)
        {
            Some(name) => {
                if name.as_str().is_empty()
                {
					result.push(
						Report::build(ReportKind::Error, token.source(), name.start())
						.with_message("Empty link name")
						.with_label(
							Label::new((token.source().clone(), name.range()))
							.with_message("Link name is empty")
							.with_color(parser.colors().error))
						.finish());
					return result;
                }
				// TODO: process into separate document...
                let text_content = util::process_text(document, name.as_str());

                if text_content.as_str().is_empty()
                {
					result.push(
						Report::build(ReportKind::Error, token.source(), name.start())
						.with_message("Empty link name")
						.with_label(
							Label::new((token.source(), name.range()))
							.with_message(format!("Link name is empty. Once processed, `{}` yields `{}`",
                                name.as_str().fg(parser.colors().highlight),
                                text_content.as_str().fg(parser.colors().highlight),
                                ))
							.with_color(parser.colors().error))
						.finish());
					return result;
                }
				text_content
            },
            _ => panic!("Empty link name"),
        };

        let link_url = match matches.get(2)
        {
            Some(url) => {
                if url.as_str().is_empty()
                {
					result.push(
						Report::build(ReportKind::Error, token.source(), url.start())
						.with_message("Empty link url")
						.with_label(
							Label::new((token.source(), url.range()))
							.with_message("Link url is empty")
							.with_color(parser.colors().error))
						.finish());
					return result;
                }
                let text_content = util::process_text(document, url.as_str());

                if text_content.as_str().is_empty()
                {
					result.push(
						Report::build(ReportKind::Error, token.source(), url.start())
						.with_message("Empty link url")
						.with_label(
							Label::new((token.source(), url.range()))
							.with_message(format!("Link url is empty. Once processed, `{}` yields `{}`",
                                url.as_str().fg(parser.colors().highlight),
                                text_content.as_str().fg(parser.colors().highlight),
                                ))
							.with_color(parser.colors().error))
						.finish());
					return result;
                }
				text_content
            },
            _ => panic!("Empty link url"),
        };

        parser.push(document, Box::new(
            Link::new(
				token.clone(),
                link_name,
                link_url
            )
        ));

        return result;
	}

	// TODO
	fn lua_bindings<'lua>(&self, _lua: &'lua Lua) -> Vec<(String, Function<'lua>)> { vec![] }
}