use regex::Regex;
use std::cmp::max;
use std::error::Error;
use std::fmt;
use std::fs::File as FsFile;
use std::io;
use std::io::{BufRead, BufReader};
use std::path::Path;

use command_runner::CommandRunner;
use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};
use resources::Resource;

pub struct WordpressTranslation<'a, C, D, R> where C: AsRef<str>, D: AsRef<str>, R: 'a + CommandRunner {
  path: D,
  version: &'a str,
  locale: C,
  command_runner: &'a R
}

impl<'a, C, R> WordpressTranslation<'a, C, String, R> where C: AsRef<str>, R: CommandRunner {
  pub fn new<D: AsRef<str>>(path: D, version: &'a str, locale: C, command_runner: &'a R) -> Self {
    WordpressTranslation {
      path: Path::new(path.as_ref()).join("wp-content/languages").to_string_lossy().to_string(),
      version,
      locale,
      command_runner
    }
  }
}

impl<'a, C, D, R> WordpressTranslation<'a, C, D, R> where C: AsRef<str>, D: AsRef<str>, R: CommandRunner {
  fn get_pairs(&self) -> Vec<(String, String)> {
    let version_x = self.version.trim_right_matches(|c: char| c.is_digit(10)).to_owned() + "x";
    let locale: &str = self.locale.as_ref();
    let path_locale = if locale == "de_DE" { "de".to_owned() } else { locale.to_lowercase().replace('_', "-") };
    let mut res = vec![];
    for &(in_slug, out_slug) in [("", ""), ("cc/", "continents-cities-"), ("admin/", "admin-"), ("admin/network/", "admin-network-")].iter() {
      for format in ["po", "mo"].iter() {
        res.push((
          format!("https://translate.wordpress.org/projects/wp/{}/{}{}/default/export-translations?format={}", version_x, in_slug, path_locale, format),
          format!("{}/{}{}.{}", self.path.as_ref(), out_slug, self.locale.as_ref(), format)
        ))
      }
    }
    res
  }
}

impl<'a, C, D, R> Symbol for WordpressTranslation<'a, C, D, R> where C: AsRef<str>, D: AsRef<str>, R: CommandRunner {
  fn target_reached(&self) -> Result<bool, Box<Error>> {
    let mut newest = String::new();
    let match_date = Regex::new("(?m)^\"PO-Revision-Date: (.+)\\+0000\\\\n\"$").unwrap();
    for (_, target) in self.get_pairs() {
      match FsFile::open(target.clone()) {
        Err(e) => {
          // Check if file exists
          return if e.kind() == io::ErrorKind::NotFound {
            Ok(false)
          } else {
            Err(Box::new(e))
          };
        },
        Ok(mut file) => if target.ends_with(".po") {
          let mut reader = BufReader::new(file);
          for content in reader.lines() {
            if let Some(match_result) = match_date.captures(&try!(content)) {
              newest = max(newest, match_result[1].to_string());
              break;
            }
          }
        }
      }
    }
    let upstream = try!(self.command_runner.get_output("curl", &[&format!("https://api.wordpress.org/core/version-check/1.7/?version={}&locale={}", self.version, self.locale.as_ref())]));
    Ok(try!(String::from_utf8(upstream)).contains(&format!(r###"language":"{}","version":"{}","updated":"{}"###, self.locale.as_ref(), self.version, newest)))
  }

  fn execute(&self) -> Result<(), Box<Error>> {
    for (source, target) in self.get_pairs() {
      try!(self.command_runner.run_successfully("curl", &["--compressed", "-o", &target, &source]));
    }
    Ok(())
  }

  fn get_prerequisites(&self) -> Vec<Resource> {
    vec![ Resource::new("dir", self.path.as_ref()) ]
  }

  fn as_action<'b>(&'b self, runner: &'b SymbolRunner) -> Box<Action + 'b> {
    Box::new(SymbolAction::new(runner, self))
  }

  fn into_action<'b>(self: Box<Self>, runner: &'b SymbolRunner) -> Box<Action + 'b> where Self: 'b {
    Box::new(OwnedSymbolAction::new(runner, *self))
  }
}

impl<'a, C, D, R> fmt::Display for WordpressTranslation<'a, C, D, R> where C: AsRef<str>, D: AsRef<str>, R: CommandRunner {
  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error>{
    write!(f, "WordpressTranslation {}", self.path.as_ref())
  }
}