// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.

//! This module provides feature to upgrade deno executable
//!
//! At the moment it is only consumed using CLI but in
//! the future it can be easily extended to provide
//! the same functions as ops available in JS runtime.

extern crate semver_parser;
use crate::futures::FutureExt;
use crate::http_util::fetch_once;
use crate::http_util::FetchOnceResult;
use crate::op_error::OpError;
use crate::ErrBox;
use regex::Regex;
use reqwest::{redirect::Policy, Client};
use semver_parser::version::parse as semver_parse;
use semver_parser::version::Version;
use std::fs;
use std::future::Future;
use std::io::prelude::*;
use std::path::Path;
use std::path::PathBuf;
use std::pin::Pin;
use std::process::Command;
use std::process::Stdio;
use std::string::String;
use tempfile::TempDir;
use url::Url;

// TODO(ry) Auto detect target triples for the uploaded files.
#[cfg(windows)]
const ARCHIVE_NAME: &str = "deno-x86_64-pc-windows-msvc.zip";
#[cfg(target_os = "macos")]
const ARCHIVE_NAME: &str = "deno-x86_64-apple-darwin.zip";
#[cfg(target_os = "linux")]
const ARCHIVE_NAME: &str = "deno-x86_64-unknown-linux-gnu.zip";

async fn get_latest_version(client: &Client) -> Result<Version, ErrBox> {
  println!("Checking for latest version");
  let body = client
    .get(Url::parse(
      "https://github.com/denoland/deno/releases/latest",
    )?)
    .send()
    .await?
    .text()
    .await?;
  let v = find_version(&body)?;
  Ok(semver_parse(&v).unwrap())
}

/// Asynchronously updates deno executable to greatest version
/// if greatest version is available.
pub async fn upgrade_command(dry_run: bool, force: bool) -> Result<(), ErrBox> {
  let client = Client::builder().redirect(Policy::none()).build()?;
  let latest_version = get_latest_version(&client).await?;
  let current_version = semver_parse(crate::version::DENO).unwrap();

  if !force && current_version >= latest_version {
    println!(
      "Local deno version {} is the most recent release",
      &crate::version::DENO
    );
  } else {
    println!(
      "New version has been found\nDeno is upgrading to version {}",
      &latest_version
    );
    let archive_data =
      download_package(&compose_url_to_exec(&latest_version)?, client).await?;

    let old_exe_path = std::env::current_exe()?;
    let new_exe_path = unpack(archive_data)?;
    let permissions = fs::metadata(&old_exe_path)?.permissions();
    fs::set_permissions(&new_exe_path, permissions)?;
    check_exe(&new_exe_path, &latest_version)?;

    if !dry_run {
      replace_exe(&new_exe_path, &old_exe_path)?;
    }

    println!("Upgrade done successfully")
  }
  Ok(())
}

fn download_package(
  url: &Url,
  client: Client,
) -> Pin<Box<dyn Future<Output = Result<Vec<u8>, ErrBox>>>> {
  println!("downloading {}", url);
  let url = url.clone();
  let fut = async move {
    match fetch_once(client.clone(), &url, None).await? {
      FetchOnceResult::Code(source, _) => Ok(source),
      FetchOnceResult::NotModified => unreachable!(),
      FetchOnceResult::Redirect(_url, _) => {
        download_package(&_url, client).await
      }
    }
  };
  fut.boxed_local()
}

fn compose_url_to_exec(version: &Version) -> Result<Url, ErrBox> {
  let s = format!(
    "https://github.com/denoland/deno/releases/download/v{}/{}",
    version, ARCHIVE_NAME
  );
  Ok(Url::parse(&s)?)
}

fn find_version(text: &str) -> Result<String, ErrBox> {
  let re = Regex::new(r#"v([^\?]+)?""#)?;
  if let Some(_mat) = re.find(text) {
    let mat = _mat.as_str();
    return Ok(mat[1..mat.len() - 1].to_string());
  }
  Err(OpError::other("Cannot read latest tag version".to_string()).into())
}

fn unpack(archive_data: Vec<u8>) -> Result<PathBuf, ErrBox> {
  // We use into_path so that the tempdir is not automatically deleted. This is
  // useful for debugging upgrade, but also so this function can return a path
  // to the newly uncompressed file without fear of the tempdir being deleted.
  let temp_dir = TempDir::new()?.into_path();
  let exe_ext = if cfg!(windows) { "exe" } else { "" };
  let exe_path = temp_dir.join("deno").with_extension(exe_ext);
  assert!(!exe_path.exists());

  let archive_ext = Path::new(ARCHIVE_NAME)
    .extension()
    .and_then(|ext| ext.to_str())
    .unwrap();
  let unpack_status = match archive_ext {
    "gz" => {
      let exe_file = fs::File::create(&exe_path)?;
      let mut cmd = Command::new("gunzip")
        .arg("-c")
        .stdin(Stdio::piped())
        .stdout(Stdio::from(exe_file))
        .spawn()?;
      cmd.stdin.as_mut().unwrap().write_all(&archive_data)?;
      cmd.wait()?
    }
    "zip" => {
      if cfg!(windows) {
        let archive_path = temp_dir.join("deno.zip");
        fs::write(&archive_path, &archive_data)?;
        Command::new("powershell.exe")
          .arg("-Command")
          .arg("Expand-Archive")
          .arg("-Path")
          .arg(&archive_path)
          .arg("-DestinationPath")
          .arg(&temp_dir)
          .spawn()?
          .wait()?
      } else {
        let archive_path = temp_dir.join("deno.zip");
        fs::write(&archive_path, &archive_data)?;
        Command::new("unzip")
          .current_dir(&temp_dir)
          .arg(archive_path)
          .spawn()?
          .wait()?
      }
    }
    ext => panic!("Unsupported archive type: '{}'", ext),
  };
  assert!(unpack_status.success());
  assert!(exe_path.exists());
  Ok(exe_path)
}

fn replace_exe(new: &Path, old: &Path) -> Result<(), ErrBox> {
  if cfg!(windows) {
    // On windows you cannot replace the currently running executable.
    // so first we rename it to deno.old.exe
    fs::rename(old, old.with_extension("old.exe"))?;
  } else {
    fs::remove_file(old)?;
  }
  // Windows cannot rename files across device boundaries, so if rename fails,
  // we try again with copy.
  fs::rename(new, old).or_else(|_| fs::copy(new, old).map(|_| ()))?;
  Ok(())
}

fn check_exe(
  exe_path: &Path,
  expected_version: &Version,
) -> Result<(), ErrBox> {
  let output = Command::new(exe_path)
    .arg("-V")
    .stderr(std::process::Stdio::inherit())
    .output()?;
  let stdout = String::from_utf8(output.stdout)?;
  assert!(output.status.success());
  assert_eq!(stdout.trim(), format!("deno {}", expected_version));
  Ok(())
}

#[test]
fn test_find_version() {
  let url = "<html><body>You are being <a href=\"https://github.com/denoland/deno/releases/tag/v0.36.0\">redirected</a>.</body></html>";
  assert_eq!(find_version(url).unwrap(), "0.36.0".to_string());
}

#[test]
fn test_compose_url_to_exec() {
  let v = semver_parse("0.0.1").unwrap();
  let url = compose_url_to_exec(&v).unwrap();
  #[cfg(windows)]
  assert_eq!(url.as_str(), "https://github.com/denoland/deno/releases/download/v0.0.1/deno-x86_64-pc-windows-msvc.zip");
  #[cfg(target_os = "macos")]
  assert_eq!(
    url.as_str(),
    "https://github.com/denoland/deno/releases/download/v0.0.1/deno-x86_64-apple-darwin.zip"
  );
  #[cfg(target_os = "linux")]
  assert_eq!(url.as_str(), "https://github.com/denoland/deno/releases/download/v0.0.1/deno-x86_64-unknown-linux-gnu.zip");
}