/* 
 * 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/.
 */

use std::{
  env,
  fs::File,
  io::Read,
};

use charsets::Charset;
use isolang::Language;
use serde::Deserialize;
use serde_with::{ serde_as, DisplayFromStr };
use toml::{ de::ValueDeserializer, Value };
use yacexits::*;

#[derive(Deserialize)]
pub struct Config {
  pub content_dir: String,
  pub output_dir: String,
  pub template_dir: String,
}

#[serde_as]
#[derive(Deserialize)]
pub struct PageMeta {
  pub author: String,
  
  pub date: String,

  #[serde_as(as = "DisplayFromStr")]
  pub encoding: Charset,

  pub lang: Language,

  pub template: String,

  pub kind: String,
}

pub fn get_path(xdg: &str) -> Result<String, (String, u32)> {
  let dir: String;
  let home_dir = match env::var("HOME").ok() {
    Some(home) => home,
    None => {
      return Err((
        "Unable to determine path to current user’s home directory."
          .to_string(),
        EX_UNAVAILABLE
      ));
    }
  };
  let mut root = false;

  if unsafe { libc::geteuid() } == 0 { root = true; }

  dir = match (root, env::var(xdg).ok()) {
    (false, Some(var)) => var,
    (su, None) => {
      match xdg {
        "XDG_CACHE_HOME" => {
          if su { "/var".to_owned() }
          else { format!("{}/.cache", home_dir) }
        },
        "XDG_CONFIG_HOME" => {
          if su { "/etc".to_owned() }
          else { format!("{}/.config", home_dir) }
        },
        "XDG_DATA_HOME" => {
          if su { "/usr/share".to_owned() }
          else { format!("{}/.local/share", home_dir) }
        },
        _ => {
          return Err(
            (format!("{}: Unimplemented variable.", xdg), EX_SOFTWARE)
          );
        },
      }
    },
    _ => {
      panic!("nya");
    },
  };
  
  Ok(format!("{}/plaque", dir))
}

impl Config {
  pub fn read_config(config_path: String) -> Result<Self, (String, u32)> {
    let mut buf: Vec<u8> = Vec::new();

    let mut config_file = match File::open(
      format!("{}/config.toml", config_path)
    ) {
      Ok(file) => file,
      Err(err) => return Err((format!("{:?}", err), 1)),
    };

    if let Some(err) = config_file.read_to_end(&mut buf).err() {
      return Err((format!("{:?}", err), EX_DATAERR));
    }

    let toml = String::from_utf8(buf).unwrap();

    match toml::from_str(&toml) {
      Ok(val) => Ok(val),
      Err(err) => Err((format!("{:?}", err), 1)),
    }
  }
}

impl PageMeta {
  pub fn read_meta(toml: Value) -> Result<Self, (String, u32)> {
    let input: String = match toml.try_into() {
      Ok(val) => val,
      Err(_) => {
        return Err((format!("Failed to read page metadata."), EX_DATAERR));
      },
    };

    match Self::deserialize(ValueDeserializer::new(&input)) {
      Ok(val) => Ok(val),
      Err(_) => {
        Err(("Invalid configuration file.".to_owned(), EX_DATAERR))
      },
    }
  }
}