# Copyright 2013 The Servo Project Developers. See the COPYRIGHT
# file at the top-level directory of this distribution.
#
# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
# option. This file may not be copied, modified, or distributed
# except according to those terms.

from __future__ import print_function, unicode_literals

import base64
import json
import os
import os.path as path
import re
import shutil
import sys
import StringIO
import tarfile
import urllib2

from mach.decorators import (
    CommandArgument,
    CommandProvider,
    Command,
)

from servo.command_base import CommandBase, host_triple, BIN_SUFFIX


def download(desc, src, writer, start_byte=0):
    if start_byte:
        print("Resuming download of %s..." % desc)
    else:
        print("Downloading %s..." % desc)
    dumb = (os.environ.get("TERM") == "dumb") or (not sys.stdout.isatty())

    try:
        if start_byte:
            src = urllib2.Request(src, headers={'Range': 'bytes={}-'.format(start_byte)})
        resp = urllib2.urlopen(src)

        fsize = None
        if resp.info().getheader('Content-Length'):
            fsize = int(resp.info().getheader('Content-Length').strip()) + start_byte

        recved = start_byte
        chunk_size = 8192

        while True:
            chunk = resp.read(chunk_size)
            if not chunk:
                break
            recved += len(chunk)
            if not dumb:
                if fsize is not None:
                    pct = recved * 100.0 / fsize
                    print("\rDownloading %s: %5.1f%%" % (desc, pct), end="")

                sys.stdout.flush()
            writer.write(chunk)

        if not dumb:
            print()
    except urllib2.HTTPError, e:
        print("Download failed (%d): %s - %s" % (e.code, e.reason, src))
        if e.code == 403:
            print("No Rust compiler binary available for this platform. "
                  "Please see https://github.com/servo/servo/#prerequisites")
        sys.exit(1)
    except urllib2.URLError, e:
        print("Error downloading Rust compiler: " + str(e.reason) + ". The failing URL was: " + src)
        sys.exit(1)
    except KeyboardInterrupt:
        writer.flush()
        raise


def download_file(desc, src, dst):
    tmp_path = dst + ".part"
    try:
        start_byte = os.path.getsize(tmp_path)
        with open(tmp_path, 'ab') as fd:
            download(desc, src, fd, start_byte=start_byte)
    except os.error:
        with open(tmp_path, 'wb') as fd:
            download(desc, src, fd)
    os.rename(tmp_path, dst)


def download_bytes(desc, src):
    content_writer = StringIO.StringIO()
    download(desc, src, content_writer)
    return content_writer.getvalue()


def extract(src, dst, movedir=None):
    tarfile.open(src).extractall(dst)

    if movedir:
        for f in os.listdir(movedir):
            frm = path.join(movedir, f)
            to = path.join(dst, f)
            os.rename(frm, to)
        os.rmdir(movedir)

    os.remove(src)


@CommandProvider
class MachCommands(CommandBase):
    @Command('env',
             description='Print environment setup commands',
             category='bootstrap')
    def env(self):
        env = self.build_env()
        print("export PATH=%s" % env["PATH"])
        if sys.platform == "darwin":
            print("export DYLD_LIBRARY_PATH=%s" % env["DYLD_LIBRARY_PATH"])
        else:
            print("export LD_LIBRARY_PATH=%s" % env["LD_LIBRARY_PATH"])

    @Command('bootstrap-rust',
             description='Download the Rust compiler',
             category='bootstrap')
    @CommandArgument('--force', '-f',
                     action='store_true',
                     help='Force download even if a copy already exists')
    @CommandArgument('--target',
                     action='append',
                     default=[],
                     help='Download rust stdlib for specified target')
    def bootstrap_rustc(self, force=False, target=[]):
        rust_dir = path.join(
            self.context.sharedir, "rust", self.rust_path())
        date = self.rust_path().split("/")[0]
        install_dir = path.join(self.context.sharedir, "rust", date)

        if not force and path.exists(path.join(rust_dir, "rustc", "bin", "rustc" + BIN_SUFFIX)):
            print("Rust compiler already downloaded.", end=" ")
            print("Use |bootstrap-rust --force| to download again.")
        else:
            if path.isdir(rust_dir):
                shutil.rmtree(rust_dir)
            os.makedirs(rust_dir)

            # The Rust compiler is hosted on the nightly server under the date with a name
            # rustc-nightly-HOST-TRIPLE.tar.gz. We just need to pull down and extract it,
            # giving a directory name that will be the same as the tarball name (rustc is
            # in that directory).
            rustc_url = ("https://static-rust-lang-org.s3.amazonaws.com/dist/%s.tar.gz"
                         % self.rust_path())
            tgz_file = rust_dir + '-rustc.tar.gz'

            download_file("Rust compiler", rustc_url, tgz_file)

            print("Extracting Rust compiler...")
            extract(tgz_file, install_dir)
            print("Rust compiler ready.")

        # Each Rust stdlib has a name of the form `rust-std-nightly-TRIPLE.tar.gz`, with
        # a directory of the name `rust-std-TRIPLE` inside and then a `lib` directory.
        # This `lib` directory needs to be extracted and merged with the `rustc/lib`
        # directory from the host compiler above.
        lib_dir = path.join(install_dir, "rustc-nightly-{}".format(host_triple()),
                            "rustc", "lib", "rustlib")

        # ensure that the libs for the host's target is downloaded
        host_target = host_triple()
        if host_target not in target:
            target.append(host_target)

        for target_triple in target:
            target_lib_dir = path.join(lib_dir, target_triple)
            if path.exists(target_lib_dir):
                # No need to check for force. If --force the directory is already deleted
                print("Rust lib for target {} already downloaded.".format(target_triple), end=" ")
                print("Use |bootstrap-rust --force| to download again.")
                continue

            std_url = ("https://static-rust-lang-org.s3.amazonaws.com/dist/%s/rust-std-nightly-%s.tar.gz"
                       % (date, target_triple))
            tgz_file = install_dir + ('rust-std-nightly-%s.tar.gz' % target_triple)

            download_file("Host rust library for target %s" % target_triple, std_url, tgz_file)
            print("Extracting Rust stdlib for target %s..." % target_triple)
            extract(tgz_file, install_dir)
            shutil.copytree(path.join(install_dir, "rust-std-nightly-%s" % target_triple,
                                      "rust-std-%s" % target_triple, "lib", "rustlib", target_triple),
                            path.join(install_dir, "rustc-nightly-%s" % host_triple(),
                                      "rustc", "lib", "rustlib", target_triple))
            shutil.rmtree(path.join(install_dir, "rust-std-nightly-%s" % target_triple))

            print("Rust {} libs ready.".format(target_triple))

    @Command('bootstrap-rust-docs',
             description='Download the Rust documentation',
             category='bootstrap')
    @CommandArgument('--force', '-f',
                     action='store_true',
                     help='Force download even if docs already exist')
    def bootstrap_rustc_docs(self, force=False):
        self.ensure_bootstrapped()
        rust_root = self.config["tools"]["rust-root"]
        docs_dir = path.join(rust_root, "doc")
        if not force and path.exists(docs_dir):
            print("Rust docs already downloaded.", end=" ")
            print("Use |bootstrap-rust-docs --force| to download again.")
            return

        if path.isdir(docs_dir):
            shutil.rmtree(docs_dir)
        docs_name = self.rust_path().replace("rustc-", "rust-docs-")
        docs_url = ("https://static-rust-lang-org.s3.amazonaws.com/dist/rust-docs-nightly-%s.tar.gz"
                    % host_triple())
        tgz_file = path.join(rust_root, 'doc.tar.gz')

        download_file("Rust docs", docs_url, tgz_file)

        print("Extracting Rust docs...")
        temp_dir = path.join(rust_root, "temp_docs")
        if path.isdir(temp_dir):
            shutil.rmtree(temp_dir)
        extract(tgz_file, temp_dir)
        shutil.move(path.join(temp_dir, docs_name.split("/")[1],
                              "rust-docs", "share", "doc", "rust", "html"),
                    docs_dir)
        shutil.rmtree(temp_dir)
        print("Rust docs ready.")

    @Command('bootstrap-cargo',
             description='Download the Cargo build tool',
             category='bootstrap')
    @CommandArgument('--force', '-f',
                     action='store_true',
                     help='Force download even if cargo already exists')
    def bootstrap_cargo(self, force=False):
        cargo_dir = path.join(self.context.sharedir, "cargo",
                              self.cargo_build_id())
        if not force and path.exists(path.join(cargo_dir, "cargo", "bin", "cargo" + BIN_SUFFIX)):
            print("Cargo already downloaded.", end=" ")
            print("Use |bootstrap-cargo --force| to download again.")
            return

        if path.isdir(cargo_dir):
            shutil.rmtree(cargo_dir)
        os.makedirs(cargo_dir)

        tgz_file = "cargo-nightly-%s.tar.gz" % host_triple()
        nightly_url = "https://static-rust-lang-org.s3.amazonaws.com/cargo-dist/%s/%s" % \
            (self.cargo_build_id(), tgz_file)

        download_file("Cargo nightly", nightly_url, tgz_file)

        print("Extracting Cargo nightly...")
        nightly_dir = path.join(cargo_dir,
                                path.basename(tgz_file).replace(".tar.gz", ""))
        extract(tgz_file, cargo_dir, movedir=nightly_dir)
        print("Cargo ready.")

    @Command('update-hsts-preload',
             description='Download the HSTS preload list',
             category='bootstrap')
    def bootstrap_hsts_preload(self, force=False):
        preload_filename = "hsts_preload.json"
        preload_path = path.join(self.context.topdir, "resources")

        chromium_hsts_url = "https://chromium.googlesource.com/chromium/src" + \
            "/net/+/master/http/transport_security_state_static.json?format=TEXT"

        try:
            content_base64 = download_bytes("Chromium HSTS preload list", chromium_hsts_url)
        except urllib2.URLError:
            print("Unable to download chromium HSTS preload list; are you connected to the internet?")
            sys.exit(1)

        content_decoded = base64.b64decode(content_base64)

        # The chromium "json" has single line comments in it which, of course,
        # are non-standard/non-valid json. Simply strip them out before parsing
        content_json = re.sub(r'(^|\s+)//.*$', '', content_decoded, flags=re.MULTILINE)

        try:
            pins_and_static_preloads = json.loads(content_json)
            entries = {
                "entries": [
                    {
                        "host": e["name"],
                        "include_subdomains": e.get("include_subdomains", False)
                    }
                    for e in pins_and_static_preloads["entries"]
                ]
            }

            with open(path.join(preload_path, preload_filename), 'w') as fd:
                json.dump(entries, fd, indent=4)
        except ValueError, e:
            print("Unable to parse chromium HSTS preload list, has the format changed?")
            sys.exit(1)

    @Command('clean-nightlies',
             description='Clean unused nightly builds of Rust and Cargo',
             category='bootstrap')
    @CommandArgument('--force', '-f',
                     action='store_true',
                     help='Actually remove stuff')
    def clean_nightlies(self, force=False):
        rust_current = self.rust_path().split('/')[0]
        cargo_current = self.cargo_build_id()
        print("Current Rust version: " + rust_current)
        print("Current Cargo version: " + cargo_current)
        removing_anything = False
        for current, base in [(rust_current, "rust"), (cargo_current, "cargo")]:
            base = path.join(self.context.sharedir, base)
            for name in os.listdir(base):
                if name != current:
                    removing_anything = True
                    name = path.join(base, name)
                    if force:
                        print("Removing " + name)
                        if os.path.isdir(name):
                            shutil.rmtree(name)
                        else:
                            os.remove(name)
                    else:
                        print("Would remove " + name)
        if not removing_anything:
            print("Nothing to remove.")
        elif not force:
            print("Nothing done. "
                  "Run `./mach clean-nightlies -f` to actually remove.")