/* 
 * Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
 * SPDX-License-Identifier: AGPL-3.0-or-later
 *
 * This file is part of Plaque.
 *
 * Plaque is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Affero General Public License as published by the Free 
 * Software Foundation, either version 3 of the License, or (at your option) any
 * later version.
 * 
 * Plaque is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see https://www.gnu.org/licenses/.
 */

mod config;

use std::{
  env::args,
  io::{ Read, Write },
  fs::{ File, ReadDir, read_dir },
};

use config::*;

use pulldown_cmark::{ Parser, Options, html };
use toml::Value;
use tl::ParserOptions;
use yacexits::*;

fn get_contents(dir: ReadDir) -> Result<Vec<(String, Value)>, (String, u32)> {
  let mut out: Vec<(String, Value)> = Vec::new();
  let mut md: String;
  let mut toml = String::new();

  for entry in dir {
    let mut buf = Vec::new();

    let file = match entry {
      Ok(file) => file,
      Err(_) => break,
    };

    let file_name = match file.file_name().into_string() {
      Ok(name) => name,
      Err(_) => {
        return Err((format!("Invalid file name."), EX_DATAERR));
      },
    };

    let contents = match File::open(&file_name) {
      Ok(mut md_file) => {
        md_file.read_to_end(&mut buf).unwrap();
        String::from_utf8(buf).unwrap()
      },
      Err(_) => {
        return Err((
          format!("{}: No such file or directory.", file_name),
          EX_UNAVAILABLE
        ));
      },
    };
    
    let mut lines = contents.lines();

    if lines.next() == Some("+++\n") {
      let mut line = lines.next();

      while line.unwrap() != "+++\n" {
        toml.push_str(&mut line.unwrap());
        line = lines.next();
      }
      md = lines.collect::<Vec<&str>>().as_mut_slice().join("");

      let parsed_toml = match toml.parse::<Value>() {
        Ok(val) => val,
        Err(_) => {
          return Err((
            format!(
              "{}: Could not parse TOML.",
              file_name,
            ),
            EX_DATAERR,
          ));
        },
      };

      out.push((md, parsed_toml));
    }
  }
  Ok(out)
}

fn main() {
  let argv = args().collect::<Vec<String>>(); 
  let mut options = Options::empty();
  options.insert(Options::all());
  
  let config_path = match get_path("XDG_CONFIG_DIR") {
    Ok(path) => path,
    Err((err, code)) => {
      eprintln!("{}: {}", argv[0], err);
      exit(code);
    },
  };
  
  let config = match Config::read_config(config_path) {
    Ok(val) => val,
    Err((err, code)) => {
      eprintln!("{}: {}", argv[0], err);
      exit(code);
    }
  };

  let content_files = match read_dir(&config.content_dir) {
    Ok(files) => files,
    Err(_) => {
      eprintln!("{}: {}: Directory not found.", argv[0], &config.content_dir);
      exit(EX_UNAVAILABLE);
    },
  };
  
  let files = match get_contents(content_files) {
    Ok(files) => files,
    Err((err, code)) => {
      eprintln!("{}: {}", argv[0], err);
      exit(code);
    },
  };
  
  for element in files.iter() {
    let (md, toml) = element;

    let meta_info = match PageMeta::read_meta(toml.to_owned()) {
      Ok(info) => info,
      Err((err, code)) => {
        eprintln!("{}: {}", argv[0], err);
        exit(code);
      },
    };

    let mut template = match File::open(format!(
        "{}/{}.html",
        config.template_dir,
        meta_info.template,
    )) {
      Ok(file) => file,
      /* 
       * TODO: better matching:
       * Err(err) => {
       *   match err {
       *     whatever_message => File does not exist
       *     whichever_message => whatever else
       */
      Err(_) => {
        eprintln!("{}: {}: File does not exist.", argv[0], meta_info.template);
        exit(EX_OSERR);
      },
    };

    let mut html: Vec<u8> = Vec::new();

    match template.read_to_end(&mut html) {
      Ok(_) => {},
      Err(err) => {
        eprintln!("{}: {}", argv[0], err);
        exit(1);
      },
    };

    let parsed_html = match String::from_utf8(html) {
      Ok(html) => html,
      Err(err) => {
        eprintln!("{}: {}", argv[0], err);
        exit(1);
      },
    };

    let dom = match tl::parse(&parsed_html, ParserOptions::default()) {
      Ok(dom) => dom,
      Err(err) => {
        eprintln!("{}: {}", argv[0], err);
        exit(1);
      },
    };

    let parser = dom.parser();

    let mut html_file = match File::create(format!(
        "{}/{}.html",
        config.output_dir,
        meta_info.template,
    )) {
      Ok(file) => file,
      Err(_) => {
        eprintln!(
          "{}: {}: Unable to create output file.",
          argv[0],
          config.output_dir,
        );
        exit(EX_OSERR);
      },
    };

    let mut output = String::new();

    html::push_html(&mut output, Parser::new_ext(&md, options));

    match html_file.write(output.as_bytes()) {
      Ok(_) => {},
      Err(err) => {
        eprintln!("{}: {}", argv[0], err);
        exit(EX_SOFTWARE);
      },
    };
  }
}