# Copyright 2015-2016 The Rust Project Developers. See the COPYRIGHT
# file at the top-level directory of this distribution and at
# http://rust-lang.org/COPYRIGHT.
#
# 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.

import argparse
import contextlib
import datetime
import hashlib
import os
import shutil
import subprocess
import sys
import tarfile
import tempfile

from time import time


def get(url, path, verbose=False):
    sha_url = url + ".sha256"
    with tempfile.NamedTemporaryFile(delete=False) as temp_file:
        temp_path = temp_file.name
    with tempfile.NamedTemporaryFile(suffix=".sha256", delete=False) as sha_file:
        sha_path = sha_file.name

    try:
        download(sha_path, sha_url, verbose)
        if os.path.exists(path):
            if verify(path, sha_path, False):
                print("using already-download file " + path)
                return
            else:
                print("ignoring already-download file " + path + " due to failed verification")
                os.unlink(path)
        download(temp_path, url, verbose)
        if not verify(temp_path, sha_path, True):
            raise RuntimeError("failed verification")
        print("moving {} to {}".format(temp_path, path))
        shutil.move(temp_path, path)
    finally:
        delete_if_present(sha_path)
        delete_if_present(temp_path)


def delete_if_present(path):
    if os.path.isfile(path):
        print("removing " + path)
        os.unlink(path)


def download(path, url, verbose):
    print("downloading {} to {}".format(url, path))
    # see http://serverfault.com/questions/301128/how-to-download
    if sys.platform == 'win32':
        run(["PowerShell.exe", "/nologo", "-Command",
             "(New-Object System.Net.WebClient)"
             ".DownloadFile('{}', '{}')".format(url, path)],
            verbose=verbose)
    else:
        run(["curl", "-o", path, url], verbose=verbose)


def verify(path, sha_path, verbose):
    print("verifying " + path)
    with open(path, "rb") as f:
        found = hashlib.sha256(f.read()).hexdigest()
    with open(sha_path, "r") as f:
        expected, _ = f.readline().split()
    verified = found == expected
    if not verified and verbose:
        print("invalid checksum:\n"
               "    found:    {}\n"
               "    expected: {}".format(found, expected))
    return verified


def unpack(tarball, dst, verbose=False, match=None):
    print("extracting " + tarball)
    fname = os.path.basename(tarball).replace(".tar.gz", "")
    with contextlib.closing(tarfile.open(tarball)) as tar:
        for p in tar.getnames():
            if "/" not in p:
                continue
            name = p.replace(fname + "/", "", 1)
            if match is not None and not name.startswith(match):
                continue
            name = name[len(match) + 1:]

            fp = os.path.join(dst, name)
            if verbose:
                print("  extracting " + p)
            tar.extract(p, dst)
            tp = os.path.join(dst, p)
            if os.path.isdir(tp) and os.path.exists(fp):
                continue
            shutil.move(tp, fp)
    shutil.rmtree(os.path.join(dst, fname))

def run(args, verbose=False):
    if verbose:
        print("running: " + ' '.join(args))
    sys.stdout.flush()
    # Use Popen here instead of call() as it apparently allows powershell on
    # Windows to not lock up waiting for input presumably.
    ret = subprocess.Popen(args)
    code = ret.wait()
    if code != 0:
        err = "failed to run: " + ' '.join(args)
        if verbose:
            raise RuntimeError(err)
        sys.exit(err)

def stage0_data(rust_root):
    nightlies = os.path.join(rust_root, "src/stage0.txt")
    data = {}
    with open(nightlies, 'r') as nightlies:
        for line in nightlies:
            line = line.rstrip()  # Strip newline character, '\n'
            if line.startswith("#") or line == '':
                continue
            a, b = line.split(": ", 1)
            data[a] = b
    return data

def format_build_time(duration):
    return str(datetime.timedelta(seconds=int(duration)))


class RustBuild(object):
    def download_stage0(self):
        cache_dst = os.path.join(self.build_dir, "cache")
        rustc_cache = os.path.join(cache_dst, self.stage0_rustc_date())
        cargo_cache = os.path.join(cache_dst, self.stage0_cargo_date())
        if not os.path.exists(rustc_cache):
            os.makedirs(rustc_cache)
        if not os.path.exists(cargo_cache):
            os.makedirs(cargo_cache)

        if self.rustc().startswith(self.bin_root()) and \
                (not os.path.exists(self.rustc()) or self.rustc_out_of_date()):
            if os.path.exists(self.bin_root()):
                shutil.rmtree(self.bin_root())
            channel = self.stage0_rustc_channel()
            filename = "rust-std-{}-{}.tar.gz".format(channel, self.build)
            url = "https://static.rust-lang.org/dist/" + self.stage0_rustc_date()
            tarball = os.path.join(rustc_cache, filename)
            if not os.path.exists(tarball):
                get("{}/{}".format(url, filename), tarball, verbose=self.verbose)
            unpack(tarball, self.bin_root(),
                   match="rust-std-" + self.build,
                   verbose=self.verbose)

            filename = "rustc-{}-{}.tar.gz".format(channel, self.build)
            url = "https://static.rust-lang.org/dist/" + self.stage0_rustc_date()
            tarball = os.path.join(rustc_cache, filename)
            if not os.path.exists(tarball):
                get("{}/{}".format(url, filename), tarball, verbose=self.verbose)
            unpack(tarball, self.bin_root(), match="rustc", verbose=self.verbose)
            with open(self.rustc_stamp(), 'w') as f:
                f.write(self.stage0_rustc_date())

        if self.cargo().startswith(self.bin_root()) and \
                (not os.path.exists(self.cargo()) or self.cargo_out_of_date()):
            channel = self.stage0_cargo_channel()
            filename = "cargo-{}-{}.tar.gz".format(channel, self.build)
            url = "https://static.rust-lang.org/cargo-dist/" + self.stage0_cargo_date()
            tarball = os.path.join(cargo_cache, filename)
            if not os.path.exists(tarball):
                get("{}/{}".format(url, filename), tarball, verbose=self.verbose)
            unpack(tarball, self.bin_root(), match="cargo", verbose=self.verbose)
            with open(self.cargo_stamp(), 'w') as f:
                f.write(self.stage0_cargo_date())

    def stage0_cargo_date(self):
        return self._cargo_date

    def stage0_cargo_channel(self):
        return self._cargo_channel

    def stage0_rustc_date(self):
        return self._rustc_date

    def stage0_rustc_channel(self):
        return self._rustc_channel

    def rustc_stamp(self):
        return os.path.join(self.bin_root(), '.rustc-stamp')

    def cargo_stamp(self):
        return os.path.join(self.bin_root(), '.cargo-stamp')

    def rustc_out_of_date(self):
        if not os.path.exists(self.rustc_stamp()) or self.clean:
            return True
        with open(self.rustc_stamp(), 'r') as f:
            return self.stage0_rustc_date() != f.read()

    def cargo_out_of_date(self):
        if not os.path.exists(self.cargo_stamp()) or self.clean:
            return True
        with open(self.cargo_stamp(), 'r') as f:
            return self.stage0_cargo_date() != f.read()

    def bin_root(self):
        return os.path.join(self.build_dir, self.build, "stage0")

    def get_toml(self, key):
        for line in self.config_toml.splitlines():
            if line.startswith(key + ' ='):
                return self.get_string(line)
        return None

    def get_mk(self, key):
        for line in iter(self.config_mk.splitlines()):
            if line.startswith(key):
                return line[line.find(':=') + 2:].strip()
        return None

    def cargo(self):
        config = self.get_toml('cargo')
        if config:
            return config
        return os.path.join(self.bin_root(), "bin/cargo" + self.exe_suffix())

    def rustc(self):
        config = self.get_toml('rustc')
        if config:
            return config
        config = self.get_mk('CFG_LOCAL_RUST')
        if config:
            return config + '/bin/rustc' + self.exe_suffix()
        return os.path.join(self.bin_root(), "bin/rustc" + self.exe_suffix())

    def get_string(self, line):
        start = line.find('"')
        end = start + 1 + line[start + 1:].find('"')
        return line[start + 1:end]

    def exe_suffix(self):
        if sys.platform == 'win32':
            return '.exe'
        else:
            return ''

    def build_bootstrap(self):
        build_dir = os.path.join(self.build_dir, "bootstrap")
        if self.clean and os.path.exists(build_dir):
            shutil.rmtree(build_dir)
        env = os.environ.copy()
        env["CARGO_TARGET_DIR"] = build_dir
        env["RUSTC"] = self.rustc()
        env["LD_LIBRARY_PATH"] = os.path.join(self.bin_root(), "lib")
        env["DYLD_LIBRARY_PATH"] = os.path.join(self.bin_root(), "lib")
        env["PATH"] = os.path.join(self.bin_root(), "bin") + \
                      os.pathsep + env["PATH"]
        self.run([self.cargo(), "build", "--manifest-path",
                  os.path.join(self.rust_root, "src/bootstrap/Cargo.toml")],
                 env)

    def run(self, args, env):
        proc = subprocess.Popen(args, env=env)
        ret = proc.wait()
        if ret != 0:
            sys.exit(ret)

    def build_triple(self):
        default_encoding = sys.getdefaultencoding()
        config = self.get_toml('build')
        if config:
            return config
        config = self.get_mk('CFG_BUILD')
        if config:
            return config
        try:
            ostype = subprocess.check_output(['uname', '-s']).strip().decode(default_encoding)
            cputype = subprocess.check_output(['uname', '-m']).strip().decode(default_encoding)
        except (subprocess.CalledProcessError, WindowsError):
            if sys.platform == 'win32':
                return 'x86_64-pc-windows-msvc'
            err = "uname not found"
            if self.verbose:
                raise Exception(err)
            sys.exit(err)

        # Darwin's `uname -s` lies and always returns i386. We have to use
        # sysctl instead.
        if ostype == 'Darwin' and cputype == 'i686':
            args = ['sysctl', 'hw.optional.x86_64']
            sysctl = subprocess.check_output(args).decode(default_encoding)
            if ': 1' in sysctl:
                cputype = 'x86_64'

        # The goal here is to come up with the same triple as LLVM would,
        # at least for the subset of platforms we're willing to target.
        if ostype == 'Linux':
            ostype = 'unknown-linux-gnu'
        elif ostype == 'FreeBSD':
            ostype = 'unknown-freebsd'
        elif ostype == 'DragonFly':
            ostype = 'unknown-dragonfly'
        elif ostype == 'Bitrig':
            ostype = 'unknown-bitrig'
        elif ostype == 'OpenBSD':
            ostype = 'unknown-openbsd'
        elif ostype == 'NetBSD':
            ostype = 'unknown-netbsd'
        elif ostype == 'Darwin':
            ostype = 'apple-darwin'
        elif ostype.startswith('MINGW'):
            # msys' `uname` does not print gcc configuration, but prints msys
            # configuration. so we cannot believe `uname -m`:
            # msys1 is always i686 and msys2 is always x86_64.
            # instead, msys defines $MSYSTEM which is MINGW32 on i686 and
            # MINGW64 on x86_64.
            ostype = 'pc-windows-gnu'
            cputype = 'i686'
            if os.environ.get('MSYSTEM') == 'MINGW64':
                cputype = 'x86_64'
        elif ostype.startswith('MSYS'):
            ostype = 'pc-windows-gnu'
        elif ostype.startswith('CYGWIN_NT'):
            cputype = 'i686'
            if ostype.endswith('WOW64'):
                cputype = 'x86_64'
            ostype = 'pc-windows-gnu'
        else:
            err = "unknown OS type: " + ostype
            if self.verbose:
                raise ValueError(err)
            sys.exit(err)

        if cputype in {'i386', 'i486', 'i686', 'i786', 'x86'}:
            cputype = 'i686'
        elif cputype in {'xscale', 'arm'}:
            cputype = 'arm'
        elif cputype == 'armv7l':
            cputype = 'arm'
            ostype += 'eabihf'
        elif cputype == 'aarch64':
            cputype = 'aarch64'
        elif cputype in {'powerpc', 'ppc', 'ppc64'}:
            cputype = 'powerpc'
        elif cputype in {'amd64', 'x86_64', 'x86-64', 'x64'}:
            cputype = 'x86_64'
        else:
            err = "unknown cpu type: " + cputype
            if self.verbose:
                raise ValueError(err)
            sys.exit(err)

        return "{}-{}".format(cputype, ostype)

def main():
    parser = argparse.ArgumentParser(description='Build rust')
    parser.add_argument('--config')
    parser.add_argument('--clean', action='store_true')
    parser.add_argument('-v', '--verbose', action='store_true')

    args = [a for a in sys.argv if a != '-h' and a != '--help']
    args, _ = parser.parse_known_args(args)

    # Configure initial bootstrap
    rb = RustBuild()
    rb.config_toml = ''
    rb.config_mk = ''
    rb.rust_root = os.path.abspath(os.path.join(__file__, '../../..'))
    rb.build_dir = os.path.join(os.getcwd(), "build")
    rb.verbose = args.verbose
    rb.clean = args.clean

    try:
        with open(args.config or 'config.toml') as config:
            rb.config_toml = config.read()
    except:
        pass
    try:
        rb.config_mk = open('config.mk').read()
    except:
        pass

    data = stage0_data(rb.rust_root)
    rb._rustc_channel, rb._rustc_date = data['rustc'].split('-', 1)
    rb._cargo_channel, rb._cargo_date = data['cargo'].split('-', 1)

    start_time = time()

    # Fetch/build the bootstrap
    rb.build = rb.build_triple()
    rb.download_stage0()
    sys.stdout.flush()
    rb.build_bootstrap()
    sys.stdout.flush()

    # Run the bootstrap
    args = [os.path.join(rb.build_dir, "bootstrap/debug/bootstrap")]
    args.append('--src')
    args.append(rb.rust_root)
    args.append('--build')
    args.append(rb.build)
    args.extend(sys.argv[1:])
    env = os.environ.copy()
    env["BOOTSTRAP_PARENT_ID"] = str(os.getpid())
    rb.run(args, env)

    end_time = time()

    print("Build completed in %s" % format_build_time(end_time - start_time))

if __name__ == '__main__':
    main()