#!/usr/bin/env python3

__license__ = 'MIT'

import argparse
import json
import hashlib
import os
import shutil
import subprocess
import sys
import tempfile
import urllib.request

from collections import OrderedDict
from typing import Dict

try:
    import requirements
except ImportError:
    exit('Requirements modules is not installed. Run "pip install requirements-parser"')

parser = argparse.ArgumentParser()
parser.add_argument('packages', nargs='*')
parser.add_argument('--python2', action='store_true',
                    help='Look for a Python 2 package')
parser.add_argument('--cleanup', choices=['scripts', 'all'],
                    help='Select what to clean up after build')
parser.add_argument('--requirements-file', '-r',
                    help='Specify requirements.txt file')
parser.add_argument('--build-only', action='store_const',
                    dest='cleanup', const='all',
                    help='Clean up all files after build')
parser.add_argument('--build-isolation', action='store_true',
                    default=False,
                    help=(
                        'Do not disable build isolation. '
                        'Mostly useful on pip that does\'t '
                        'support the feature.'
                    ))
parser.add_argument('--checker-data', action='store_true',
                    help='Include x-checker-data in output for the "Flatpak External Data Checker"')
parser.add_argument('--output', '-o',
                    help='Specify output file name')
parser.add_argument('--runtime',
                    help='Specify a flatpak to run pip inside of a sandbox, ensures python version compatibility')
parser.add_argument('--yaml', action='store_true',
                    help='Use YAML as output format instead of JSON')
opts = parser.parse_args()

if opts.yaml:
    try:
        import yaml
    except ImportError:
        exit('PyYAML modules is not installed. Run "pip install PyYAML"')


def get_pypi_url(name: str, filename: str) -> str:
    url = 'https://pypi.org/pypi/{}/json'.format(name)
    print('Extracting download url for', name)
    with urllib.request.urlopen(url) as response:
        body = json.loads(response.read().decode('utf-8'))
        for release in body['releases'].values():
            for source in release:
                if source['filename'] == filename:
                    return source['url']
        raise Exception('Failed to extract url from {}'.format(url))


def get_tar_package_url_pypi(name: str, version: str) -> str:
    url = 'https://pypi.org/pypi/{}/{}/json'.format(name, version)
    with urllib.request.urlopen(url) as response:
        body = json.loads(response.read().decode('utf-8'))
        for ext in ['bz2', 'gz', 'xz', 'zip']:
            for source in body['urls']:
                if source['url'].endswith(ext):
                    return source['url']
        err = 'Failed to get {}-{} source from {}'.format(name, version, url)
        raise Exception(err)


def get_package_name(filename: str) -> str:
    if filename.endswith(('bz2', 'gz', 'xz', 'zip')):
        segments = filename.split('-')
        if len(segments) == 2:
            return segments[0]
        return '-'.join(segments[:len(segments) - 1])
    elif filename.endswith('whl'):
        segments = filename.split('-')
        if len(segments) == 5:
            return segments[0]
        candidate = segments[:len(segments) - 4]
        # Some packages list the version number twice
        # e.g. PyQt5-5.15.0-5.15.0-cp35.cp36.cp37.cp38-abi3-manylinux2014_x86_64.whl
        if candidate[-1] == segments[len(segments) - 4]:
            return '-'.join(candidate[:-1])
        return '-'.join(candidate)
    else:
        raise Exception(
            'Downloaded filename: {} does not end with bz2, gz, xz, zip, or whl'.format(filename)
        )


def get_file_version(filename: str) -> str:
    name = get_package_name(filename)
    segments = filename.split(name + '-')
    version = segments[1].split('-')[0]
    for ext in ['tar.gz', 'whl', 'tar.xz', 'tar.gz', 'tar.bz2', 'zip']:
        version = version.replace('.' + ext, '')
    return version


def get_file_hash(filename: str) -> str:
    sha = hashlib.sha256()
    print('Generating hash for', filename.split('/')[-1])
    with open(filename, 'rb') as f:
        while True:
            data = f.read(1024 * 1024 * 32)
            if not data:
                break
            sha.update(data)
        return sha.hexdigest()


def download_tar_pypi(url: str, tempdir: str) -> None:
    with urllib.request.urlopen(url) as response:
        file_path = os.path.join(tempdir, url.split('/')[-1])
        with open(file_path, 'x+b') as tar_file:
            shutil.copyfileobj(response, tar_file)


def parse_continuation_lines(fin):
    for line in fin:
        line = line.rstrip('\n')
        while line.endswith('\\'):
            try:
                line = line[:-1] + next(fin).rstrip('\n')
            except StopIteration:
                exit('Requirements have a wrong number of line continuation characters "\\"')
        yield line


def fprint(string: str) -> None:
    separator = '=' * 72  # Same as `flatpak-builder`
    print(separator)
    print(string)
    print(separator)


packages = []
if opts.requirements_file:
    requirements_file = os.path.expanduser(opts.requirements_file)
    try:
        with open(requirements_file, 'r') as req_file:
            reqs = parse_continuation_lines(req_file)
            reqs_as_str = '\n'.join([r.split('--hash')[0] for r in reqs])
            packages = list(requirements.parse(reqs_as_str))
    except FileNotFoundError:
        pass

elif opts.packages:
    packages = list(requirements.parse('\n'.join(opts.packages)))
    with tempfile.NamedTemporaryFile('w', delete=False, prefix='requirements.') as req_file:
        req_file.write('\n'.join(opts.packages))
        requirements_file = req_file.name
else:
    exit('Please specifiy either packages or requirements file argument')

for i in packages:
    if i["name"].lower().startswith("pyqt"):
        print("PyQt packages are not supported by flapak-pip-generator")
        print("However, there is a BaseApp for PyQt available, that you should use")
        print("Visit https://github.com/flathub/com.riverbankcomputing.PyQt.BaseApp for more information")
        sys.exit(0)

with open(requirements_file, 'r') as req_file:
    use_hash = '--hash=' in req_file.read()

python_version = '2' if opts.python2 else '3'
if opts.python2:
    pip_executable = 'pip2'
else:
    pip_executable = 'pip3'

if opts.runtime:
    flatpak_cmd = [
        'flatpak',
        '--devel',
        '--share=network',
        '--filesystem=/tmp',
        '--command={}'.format(pip_executable),
        'run',
        opts.runtime
    ]
    if opts.requirements_file:
        requirements_file = os.path.expanduser(opts.requirements_file)
        if os.path.exists(requirements_file):
            prefix = os.path.realpath(requirements_file)
            flag = '--filesystem={}'.format(prefix)
            flatpak_cmd.insert(1,flag)
else:
    flatpak_cmd = [pip_executable]

if opts.output:
    output_package = opts.output
elif opts.requirements_file:
    output_package = 'python{}-{}'.format(
        python_version,
        os.path.basename(opts.requirements_file).replace('.txt', ''),
    )
elif len(packages) == 1:
    output_package = 'python{}-{}'.format(
        python_version, packages[0].name,
    )
else:
    output_package = 'python{}-modules'.format(python_version)
if opts.yaml:
    output_filename = output_package + '.yaml'
else:
    output_filename = output_package + '.json'

modules = []
vcs_modules = []
sources = {}

tempdir_prefix = 'pip-generator-{}'.format(os.path.basename(output_package))
with tempfile.TemporaryDirectory(prefix=tempdir_prefix) as tempdir:
    pip_download = flatpak_cmd + [
        'download',
        '--exists-action=i',
        '--dest',
        tempdir,
        '-r',
        requirements_file
    ]
    if use_hash:
        pip_download.append('--require-hashes')

    fprint('Downloading sources')
    cmd = ' '.join(pip_download)
    print('Running: "{}"'.format(cmd))
    try:
        subprocess.run(pip_download, check=True)
    except subprocess.CalledProcessError:
        print('Failed to download')
        print('Please fix the module manually in the generated file')

    if not opts.requirements_file:
        try:
            os.remove(requirements_file)
        except FileNotFoundError:
            pass

    fprint('Downloading arch independent packages')
    for filename in os.listdir(tempdir):
        if not filename.endswith(('bz2', 'any.whl', 'gz', 'xz', 'zip')):
            version = get_file_version(filename)
            name = get_package_name(filename)
            url = get_tar_package_url_pypi(name, version)
            print('Deleting', filename)
            try:
                os.remove(os.path.join(tempdir, filename))
            except FileNotFoundError:
                pass
            print('Downloading {}'.format(url))
            download_tar_pypi(url, tempdir)

    files = {get_package_name(f): [] for f in os.listdir(tempdir)}

    for filename in os.listdir(tempdir):
        name = get_package_name(filename)
        files[name].append(filename)

    # Delete redundant sources, for vcs sources
    for name in files:
        if len(files[name]) > 1:
            zip_source = False
            for f in files[name]:
                if f.endswith('.zip'):
                    zip_source = True
            if zip_source:
                for f in files[name]:
                    if not f.endswith('.zip'):
                        try:
                            os.remove(os.path.join(tempdir, f))
                        except FileNotFoundError:
                            pass

    vcs_packages = {
        x.name: {'vcs': x.vcs, 'revision': x.revision, 'uri': x.uri}
        for x in packages
        if x.vcs
    }

    fprint('Obtaining hashes and urls')
    for filename in os.listdir(tempdir):
        name = get_package_name(filename)
        sha256 = get_file_hash(os.path.join(tempdir, filename))

        if name in vcs_packages:
            uri = vcs_packages[name]['uri']
            revision = vcs_packages[name]['revision']
            vcs = vcs_packages[name]['vcs']
            url = 'https://' + uri.split('://', 1)[1]
            s = 'commit'
            if vcs == 'svn':
                s = 'revision'
            source = OrderedDict([
                ('type', vcs),
                ('url', url),
                (s, revision),
            ])
            is_vcs = True
        else:
            url = get_pypi_url(name, filename)
            source = OrderedDict([
                ('type', 'file'),
                ('url', url),
                ('sha256', sha256)])
            if opts.checker_data:
                source['x-checker-data'] = {
                    'type': 'pypi',
                    'name': name}
                if url.endswith(".whl"):
                    source['x-checker-data']['packagetype'] = 'bdist_wheel'
            is_vcs = False
        sources[name] = {'source': source, 'vcs': is_vcs}

# Python3 packages that come as part of org.freedesktop.Sdk.
system_packages = ['cython', 'easy_install', 'mako', 'markdown', 'meson', 'pip', 'pygments', 'setuptools', 'six', 'wheel']

fprint('Generating dependencies')
for package in packages:

    if package.name is None:
        print('Warning: skipping invalid requirement specification {} because it is missing a name'.format(package.line), file=sys.stderr)
        print('Append #egg=<pkgname> to the end of the requirement line to fix', file=sys.stderr)
        continue
    elif package.name.casefold() in system_packages:
        print(f"{package.name} is in system_packages. Skipping.")
        continue

    if len(package.extras) > 0:
        extras = '[' + ','.join(extra for extra in package.extras) + ']'
    else:
        extras = ''

    version_list = [x[0] + x[1] for x in package.specs]
    version = ','.join(version_list)

    if package.vcs:
        revision = ''
        if package.revision:
            revision = '@' + package.revision
        pkg = package.uri + revision + '#egg=' + package.name
    else:
        pkg = package.name + extras + version

    dependencies = []
    # Downloads the package again to list dependencies

    tempdir_prefix = 'pip-generator-{}'.format(package.name)
    with tempfile.TemporaryDirectory(prefix='{}-{}'.format(tempdir_prefix, package.name)) as tempdir:
        pip_download = flatpak_cmd + [
            'download',
            '--exists-action=i',
            '--dest',
            tempdir,
        ]
        try:
            print('Generating dependencies for {}'.format(package.name))
            subprocess.run(pip_download + [pkg], check=True, stdout=subprocess.DEVNULL)
            for filename in sorted(os.listdir(tempdir)):
                dep_name = get_package_name(filename)
                if dep_name.casefold() in system_packages:
                    continue
                dependencies.append(dep_name)

        except subprocess.CalledProcessError:
            print('Failed to download {}'.format(package.name))

    is_vcs = True if package.vcs else False
    package_sources = []
    for dependency in dependencies:
        if dependency in sources:
            source = sources[dependency]
        elif dependency.replace('_', '-') in sources:
            source = sources[dependency.replace('_', '-')]
        else:
            continue

        if not (not source['vcs'] or is_vcs):
            continue

        package_sources.append(source['source'])

    if package.vcs:
        name_for_pip = '.'
    else:
        name_for_pip = pkg

    module_name = 'python{}-{}'.format(python_version, package.name)

    pip_command = [
        pip_executable,
        'install',
        '--verbose',
        '--exists-action=i',
        '--no-index',
        '--find-links="file://${PWD}"',
        '--prefix=${FLATPAK_DEST}',
        '"{}"'.format(name_for_pip)
    ]
    if not opts.build_isolation:
        pip_command.append('--no-build-isolation')

    module = OrderedDict([
        ('name', module_name),
        ('buildsystem', 'simple'),
        ('build-commands', [' '.join(pip_command)]),
        ('sources', package_sources),
    ])
    if opts.cleanup == 'all':
        module['cleanup'] = ['*']
    elif opts.cleanup == 'scripts':
        module['cleanup'] = ['/bin', '/share/man/man1']

    if package.vcs:
        vcs_modules.append(module)
    else:
        modules.append(module)

modules = vcs_modules + modules
if len(modules) == 1:
    pypi_module = modules[0]
else:
    pypi_module = {
        'name': output_package,
        'buildsystem': 'simple',
        'build-commands': [],
        'modules': modules,
    }

print()
with open(output_filename, 'w') as output:
    if opts.yaml:
        class OrderedDumper(yaml.Dumper):
            def increase_indent(self, flow=False, indentless=False):
                return super(OrderedDumper, self).increase_indent(flow, False)

        def dict_representer(dumper, data):
            return dumper.represent_dict(data.items())

        OrderedDumper.add_representer(OrderedDict, dict_representer)

        output.write("# Generated with flatpak-pip-generator " + " ".join(sys.argv[1:]) + "\n")
        yaml.dump(pypi_module, output, Dumper=OrderedDumper)
    else:
        output.write(json.dumps(pypi_module, indent=4))
    print('Output saved to {}'.format(output_filename))
