# 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.

from __future__ import print_function
import argparse
import contextlib
import datetime
import hashlib
import os
import re
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, False, verbose)
        if os.path.exists(path):
            if verify(path, sha_path, False):
                if verbose:
                    print("using already-download file " + path)
                return
            else:
                if verbose:
                    print("ignoring already-download file " +
                          path + " due to failed verification")
                os.unlink(path)
        download(temp_path, url, True, verbose)
        if not verify(temp_path, sha_path, verbose):
            raise RuntimeError("failed verification")
        if verbose:
            print("moving {} to {}".format(temp_path, path))
        shutil.move(temp_path, path)
    finally:
        delete_if_present(sha_path, verbose)
        delete_if_present(temp_path, verbose)


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


def download(path, url, probably_big, verbose):
    for x in range(0, 4):
        try:
            _download(path, url, probably_big, verbose, True)
            return
        except RuntimeError:
            print("\nspurious failure, trying again")
    _download(path, url, probably_big, verbose, False)


def _download(path, url, probably_big, verbose, exception):
    if probably_big or verbose:
        print("downloading {}".format(url))
    # 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,
            exception=exception)
    else:
        if probably_big or verbose:
            option = "-#"
        else:
            option = "-s"
        run(["curl", option, "--retry", "3", "-Sf", "-o", path, url],
            verbose=verbose,
            exception=exception)


def verify(path, sha_path, verbose):
    if 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()[0]
    verified = found == expected
    if not verified:
        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, exception=False, **kwargs):
    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, **kwargs)
    code = ret.wait()
    if code != 0:
        err = "failed to run: " + ' '.join(args)
        if verbose or exception:
            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_date())
        if not os.path.exists(rustc_cache):
            os.makedirs(rustc_cache)

        rustc_channel = self.stage0_rustc_channel()
        cargo_channel = self.stage0_cargo_channel()

        if self.rustc().startswith(self.bin_root()) and \
                (not os.path.exists(self.rustc()) or self.rustc_out_of_date()):
            self.print_what_it_means_to_bootstrap()
            if os.path.exists(self.bin_root()):
                shutil.rmtree(self.bin_root())
            filename = "rust-std-{}-{}.tar.gz".format(
                rustc_channel, self.build)
            url = self._download_url + "/dist/" + self.stage0_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(rustc_channel, self.build)
            url = self._download_url + "/dist/" + self.stage0_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)
            self.fix_executable(self.bin_root() + "/bin/rustc")
            self.fix_executable(self.bin_root() + "/bin/rustdoc")
            with open(self.rustc_stamp(), 'w') as f:
                f.write(self.stage0_date())

            if "pc-windows-gnu" in self.build:
                filename = "rust-mingw-{}-{}.tar.gz".format(
                    rustc_channel, self.build)
                url = self._download_url + "/dist/" + self.stage0_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-mingw", verbose=self.verbose)

        if self.cargo().startswith(self.bin_root()) and \
                (not os.path.exists(self.cargo()) or self.cargo_out_of_date()):
            self.print_what_it_means_to_bootstrap()
            filename = "cargo-{}-{}.tar.gz".format(cargo_channel, self.build)
            url = self._download_url + "/dist/" + self.stage0_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="cargo", verbose=self.verbose)
            self.fix_executable(self.bin_root() + "/bin/cargo")
            with open(self.cargo_stamp(), 'w') as f:
                f.write(self.stage0_date())

    def fix_executable(self, fname):
        # If we're on NixOS we need to change the path to the dynamic loader

        default_encoding = sys.getdefaultencoding()
        try:
            ostype = subprocess.check_output(
                ['uname', '-s']).strip().decode(default_encoding)
        except (subprocess.CalledProcessError, WindowsError):
            return

        if ostype != "Linux":
            return

        if not os.path.exists("/etc/NIXOS"):
            return
        if os.path.exists("/lib"):
            return

        # At this point we're pretty sure the user is running NixOS
        print("info: you seem to be running NixOS. Attempting to patch " + fname)

        try:
            interpreter = subprocess.check_output(
                ["patchelf", "--print-interpreter", fname])
            interpreter = interpreter.strip().decode(default_encoding)
        except subprocess.CalledProcessError as e:
            print("warning: failed to call patchelf: %s" % e)
            return

        loader = interpreter.split("/")[-1]

        try:
            ldd_output = subprocess.check_output(
                ['ldd', '/run/current-system/sw/bin/sh'])
            ldd_output = ldd_output.strip().decode(default_encoding)
        except subprocess.CalledProcessError as e:
            print("warning: unable to call ldd: %s" % e)
            return

        for line in ldd_output.splitlines():
            libname = line.split()[0]
            if libname.endswith(loader):
                loader_path = libname[:len(libname) - len(loader)]
                break
        else:
            print("warning: unable to find the path to the dynamic linker")
            return

        correct_interpreter = loader_path + loader

        try:
            subprocess.check_output(
                ["patchelf", "--set-interpreter", correct_interpreter, fname])
        except subprocess.CalledProcessError as e:
            print("warning: failed to call patchelf: %s" % e)
            return

    def stage0_date(self):
        return self._date

    def stage0_rustc_channel(self):
        return self._rustc_channel

    def stage0_cargo_channel(self):
        return self._cargo_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_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_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():
            match = re.match(r'^{}\s*=(.*)$'.format(key), line)
            if match is not None:
                value = match.group(1)
                return self.get_string(value) or value.strip()
        return None

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

    def cargo(self):
        config = self.get_toml('cargo')
        if config:
            return config
        config = self.get_mk('CFG_LOCAL_RUST_ROOT')
        if config:
            return config + '/bin/cargo' + self.exe_suffix()
        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_ROOT')
        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('"')
        if start == -1:
            return None
        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 print_what_it_means_to_bootstrap(self):
        if hasattr(self, 'printed'):
            return
        self.printed = True
        if os.path.exists(self.bootstrap_binary()):
            return
        if not '--help' in sys.argv or len(sys.argv) == 1:
            return

        print('info: the build system for Rust is written in Rust, so this')
        print('      script is now going to download a stage0 rust compiler')
        print('      and then compile the build system itself')
        print('')
        print('info: in the meantime you can read more about rustbuild at')
        print('      src/bootstrap/README.md before the download finishes')

    def bootstrap_binary(self):
        return os.path.join(self.build_dir, "bootstrap/debug/bootstrap")

    def build_bootstrap(self):
        self.print_what_it_means_to_bootstrap()
        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["RUSTC_BOOTSTRAP"] = '1'
        env["CARGO_TARGET_DIR"] = build_dir
        env["RUSTC"] = self.rustc()
        env["LD_LIBRARY_PATH"] = os.path.join(self.bin_root(), "lib") + \
            (os.pathsep + env["LD_LIBRARY_PATH"]) \
            if "LD_LIBRARY_PATH" in env else ""
        env["DYLD_LIBRARY_PATH"] = os.path.join(self.bin_root(), "lib") + \
            (os.pathsep + env["DYLD_LIBRARY_PATH"]) \
            if "DYLD_LIBRARY_PATH" in env else ""
        env["LIBRARY_PATH"] = os.path.join(self.bin_root(), "lib") + \
            (os.pathsep + env["LIBRARY_PATH"]) \
            if "LIBRARY_PATH" in env else ""
        env["PATH"] = os.path.join(self.bin_root(), "bin") + \
            os.pathsep + env["PATH"]
        if not os.path.isfile(self.cargo()):
            raise Exception("no cargo executable found at `%s`" % self.cargo())
        args = [self.cargo(), "build", "--manifest-path",
                os.path.join(self.rust_root, "src/bootstrap/Cargo.toml")]
        if self.verbose:
            args.append("--verbose")
            if self.verbose > 1:
                args.append("--verbose")
        if self.use_locked_deps:
            args.append("--locked")
        if self.use_vendored_sources:
            args.append("--frozen")
        run(args, env=env, verbose=self.verbose)

    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, OSError):
            if sys.platform == 'win32':
                return 'x86_64-pc-windows-msvc'
            err = "uname not found"
            if self.verbose:
                raise Exception(err)
            sys.exit(err)

        # 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':
            os_from_sp = subprocess.check_output(
                ['uname', '-o']).strip().decode(default_encoding)
            if os_from_sp == 'Android':
                ostype = 'linux-android'
            else:
                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 == 'SunOS':
            ostype = 'sun-solaris'
            # On Solaris, uname -m will return a machine classification instead
            # of a cpu type, so uname -p is recommended instead.  However, the
            # output from that option is too generic for our purposes (it will
            # always emit 'i386' on x86/amd64 systems).  As such, isainfo -k
            # must be used instead.
            try:
                cputype = subprocess.check_output(['isainfo',
                                                   '-k']).strip().decode(default_encoding)
            except (subprocess.CalledProcessError, OSError):
                err = "isainfo not found"
                if self.verbose:
                    raise Exception(err)
                sys.exit(err)
        elif ostype == 'Darwin':
            ostype = 'apple-darwin'
        elif ostype == 'Haiku':
            ostype = 'unknown-haiku'
        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'
            if ostype == 'linux-android':
                ostype = 'linux-androideabi'
        elif cputype == 'armv6l':
            cputype = 'arm'
            if ostype == 'linux-android':
                ostype = 'linux-androideabi'
            else:
                ostype += 'eabihf'
        elif cputype in {'armv7l', 'armv8l'}:
            cputype = 'armv7'
            if ostype == 'linux-android':
                ostype = 'linux-androideabi'
            else:
                ostype += 'eabihf'
        elif cputype in {'aarch64', 'arm64'}:
            cputype = 'aarch64'
        elif cputype == 'mips':
            if sys.byteorder == 'big':
                cputype = 'mips'
            elif sys.byteorder == 'little':
                cputype = 'mipsel'
            else:
                raise ValueError('unknown byteorder: ' + sys.byteorder)
        elif cputype == 'mips64':
            if sys.byteorder == 'big':
                cputype = 'mips64'
            elif sys.byteorder == 'little':
                cputype = 'mips64el'
            else:
                raise ValueError('unknown byteorder: ' + sys.byteorder)
            # only the n64 ABI is supported, indicate it
            ostype += 'abi64'
        elif cputype in {'powerpc', 'ppc'}:
            cputype = 'powerpc'
        elif cputype in {'powerpc64', 'ppc64'}:
            cputype = 'powerpc64'
        elif cputype in {'powerpc64le', 'ppc64le'}:
            cputype = 'powerpc64le'
        elif cputype == 'sparcv9':
            pass
        elif cputype in {'amd64', 'x86_64', 'x86-64', 'x64'}:
            cputype = 'x86_64'
        elif cputype == 's390x':
            cputype = 's390x'
        elif cputype == 'BePC':
            cputype = 'i686'
        else:
            err = "unknown cpu type: " + cputype
            if self.verbose:
                raise ValueError(err)
            sys.exit(err)

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

    def update_submodules(self):
        if (not os.path.exists(os.path.join(self.rust_root, ".git"))) or \
                self.get_toml('submodules') == "false" or \
                self.get_mk('CFG_DISABLE_MANAGE_SUBMODULES') == "1":
            return
        print('Updating submodules')
        default_encoding = sys.getdefaultencoding()
        run(["git", "submodule", "-q", "sync"], cwd=self.rust_root)
        submodules = [s.split(' ', 1)[1] for s in subprocess.check_output(
            ["git", "config", "--file", os.path.join(self.rust_root, ".gitmodules"),
             "--get-regexp", "path"]
        ).decode(default_encoding).splitlines()]
        submodules = [module for module in submodules
                      if not ((module.endswith("llvm") and
                               (self.get_toml('llvm-config') or self.get_mk('CFG_LLVM_ROOT'))) or
                              (module.endswith("jemalloc") and
                               (self.get_toml('jemalloc') or self.get_mk('CFG_JEMALLOC_ROOT'))))
                     ]
        run(["git", "submodule", "update",
                  "--init"] + submodules, cwd=self.rust_root, verbose=self.verbose)
        run(["git", "submodule", "-q", "foreach", "git",
                  "reset", "-q", "--hard"], cwd=self.rust_root, verbose=self.verbose)
        run(["git", "submodule", "-q", "foreach", "git",
                  "clean", "-qdfx"], cwd=self.rust_root, verbose=self.verbose)


def bootstrap():
    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

    if '\nverbose = 2' in rb.config_toml:
        rb.verbose = 2
    elif '\nverbose = 1' in rb.config_toml:
        rb.verbose = 1

    rb.use_vendored_sources = '\nvendor = true' in rb.config_toml or \
                              'CFG_ENABLE_VENDOR' in rb.config_mk

    rb.use_locked_deps = '\nlocked-deps = true' in rb.config_toml or \
                         'CFG_ENABLE_LOCKED_DEPS' in rb.config_mk

    if 'SUDO_USER' in os.environ and not rb.use_vendored_sources:
        if os.environ.get('USER') != os.environ['SUDO_USER']:
            rb.use_vendored_sources = True
            print('info: looks like you are running this command under `sudo`')
            print('      and so in order to preserve your $HOME this will now')
            print('      use vendored sources by default. Note that if this')
            print('      does not work you should run a normal build first')
            print('      before running a command like `sudo make install`')

    if rb.use_vendored_sources:
        if not os.path.exists('.cargo'):
            os.makedirs('.cargo')
        with open('.cargo/config', 'w') as f:
            f.write("""
                [source.crates-io]
                replace-with = 'vendored-sources'
                registry = 'https://example.com'

                [source.vendored-sources]
                directory = '{}/src/vendor'
            """.format(rb.rust_root))
    else:
        if os.path.exists('.cargo'):
            shutil.rmtree('.cargo')

    data = stage0_data(rb.rust_root)
    rb._date = data['date']
    rb._rustc_channel = data['rustc']
    rb._cargo_channel = data['cargo']
    if 'dev' in data:
        rb._download_url = 'https://dev-static.rust-lang.org'
    else:
        rb._download_url = 'https://static.rust-lang.org'

    rb.update_submodules()

    # 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 = [rb.bootstrap_binary()]
    args.extend(sys.argv[1:])
    env = os.environ.copy()
    env["BUILD"] = rb.build
    env["SRC"] = rb.rust_root
    env["BOOTSTRAP_PARENT_ID"] = str(os.getpid())
    env["BOOTSTRAP_PYTHON"] = sys.executable
    run(args, env=env, verbose=rb.verbose)


def main():
    start_time = time()
    help_triggered = (
        '-h' in sys.argv) or ('--help' in sys.argv) or (len(sys.argv) == 1)
    try:
        bootstrap()
        if not help_triggered:
            print("Build completed successfully in %s" %
                  format_build_time(time() - start_time))
    except (SystemExit, KeyboardInterrupt) as e:
        if hasattr(e, 'code') and isinstance(e.code, int):
            exit_code = e.code
        else:
            exit_code = 1
            print(e)
        if not help_triggered:
            print("Build completed unsuccessfully in %s" %
                  format_build_time(time() - start_time))
        sys.exit(exit_code)

if __name__ == '__main__':
    main()