#! /usr/bin/python3
# vim: et ts=4 sw=4

# Copyright © 2010-2012 Piotr Ożarowski <piotr@debian.org>
# Copyright © 2010 Canonical Ltd
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import logging
import optparse
import os
import struct
import sys
from os import environ, listdir, mkdir
from os.path import dirname, exists, isdir, join
from subprocess import PIPE, Popen
sys.path.insert(1, '/usr/share/python3/')
from debpython.version import SUPPORTED, debsorted, vrepr, \
    get_requested_versions, parse_vrange, getver
from debpython import files as dpf, PUBLIC_DIR_RE, memoize
from debpython.interpreter import Interpreter
from debpython.option import Option, compile_regexpr

# initialize script
logging.basicConfig(format='%(levelname).1s: %(module)s:%(lineno)d: '
                           '%(message)s')
log = logging.getLogger(__name__)
STDINS = {}
WORKERS = {}

"""TODO: move it to manpage
Examples:
    pycompile -p python3-mako # package's public files
    pycompile -p python3-foo /usr/share/foo # package's private files
    pycompile -V 3.1 /usr/lib/python3.1/ # python3.1 only
    pycompile -V 3.1 /usr/lib/foo/bar.py # python3.1 only
    pycompile -V 3.2- /usr/lib/python3/
"""


### EXCLUDES ###################################################
@memoize
def get_exclude_patterns_from_dir(name='/usr/share/python3/bcep/'):
    """Return patterns for files that shouldn't be bytecompiled."""
    if not isdir(name):
        return []

    result = []
    for fn in listdir(name):
        if fn.startswith('.'):
            continue
        with open(join(name, fn), 'r', encoding='utf-8') as lines:
            for line in lines:
                if line.startswith('#'):
                    continue
                line = line.rstrip('\n')

                try:
                    type_, vrange, dname, pattern = line.split('|', 3)
                except ValueError:
                    pattern = '.*'
                    type_, vrange, dname = line.split('|', 2)
                if type_ != 'file':
                    dname = dname.rstrip('/') + '/'  # make sure it ends with slash
                vrange = parse_vrange(vrange)

                versions = get_requested_versions(vrange, available=True)
                if not versions:
                    # pattern doesn't match installed Python versions
                    continue

                if type_ == 're' or pattern:
                    try:
                        pattern = compile_regexpr(None, None, pattern)
                    except Exception:
                        log.warning('skipping invalid pattern in file %s, line: %s', fn, line)
                        continue

                result.append((type_, versions, dname, pattern))
    return result


def get_exclude_patterns(directory='/', patterns=None, versions=None):
    """Return patterns for files that shouldn't be compiled in given dir."""

    # make sure directory name ends with a slash
    directory = directory.rstrip('/') + '/'

    if versions is not None:
        # make sure it's a set (debsorted returns a list)
        versions = set(versions)
    if patterns:
        if versions is None:
            versions = set(SUPPORTED)
        patterns = [('re', versions, directory, i) for i in patterns]
    else:
        patterns = []

    for type_, vers, dname, pattern in get_exclude_patterns_from_dir():
        # skip patterns that do not match requested directory
        if not dname.startswith(directory[:len(dname)]):
            continue
        # skip patterns that do not match requested versions
        if versions and not versions & vers:
            continue
        patterns.append((type_, vers, dname, pattern))
    return patterns


def filter_files(files, e_patterns, compile_versions):
    """Generate (file, versions_to_compile) pairs."""
    for fpath in files:
        valid_versions = set(compile_versions)  # all by default

        for type_, vers, dname, pattern in e_patterns:
            if not fpath.startswith(dname):
                continue
            rfpath = fpath[len(dname):]  # relative to dname

            if type_ == 'dir':  # fpath.startswith(dname) - see above
                valid_versions = valid_versions - vers
            elif type_ == 'file' and fpath == dname:
                valid_versions = valid_versions - vers
            elif type_ == 're' and (pattern.match(fpath) or pattern.match(rfpath)):
                # NOTE: directory is checked at the beginning of this loop
                valid_versions = valid_versions - vers

            # move to the next file if all versions were removed
            if not valid_versions:
                break
        if valid_versions:
            public_dir = PUBLIC_DIR_RE.match(fpath)
            if public_dir and len(public_dir.group(1)) != 1:
                yield fpath, set([getver(public_dir.group(1))])
            else:
                yield fpath, valid_versions


### COMPILE ####################################################
def py_compile(version, optimize, workers):
    if not isinstance(version, str):
        version = vrepr(version)
    cmd = "/usr/bin/python%s%s -m py_compile -" \
        % (version, ' -O' if optimize else '')
    process = Popen(cmd, bufsize=0, shell=True,
                    stdin=PIPE, close_fds=True)
    workers[version] = process  # keep the reference for .communicate()
    stdin = process.stdin
    while True:
        filename = (yield)
        stdin.write(filename.encode('utf-8') + b'\n')


def compile(files, versions, force, optimize, e_patterns=None):
    global STDINS, WORKERS
    # start Python interpreters that will handle byte compilation
    for version in versions:
        if version not in STDINS:
            coroutine = py_compile(version, optimize, WORKERS)
            next(coroutine)
            STDINS[version] = coroutine

    interpreter = Interpreter('python' if not optimize else 'python -O')

    # byte compile files
    skip_dirs = set()
    for fn, versions_to_compile in filter_files(files, e_patterns, versions):
        for version in versions_to_compile:
            cfn = interpreter.cache_file(fn, version)
            if version == (3, 1):
                if exists(cfn) and not force:
                    ftime = os.stat(fn).st_mtime
                    try:
                        ctime = os.stat(cfn).st_mtime
                    except os.error:
                        ctime = 0
                    if ctime > ftime:
                        continue
            else:
                pycache_dir = dirname(cfn)
                if not force:
                    try:
                        mtime = int(os.stat(fn).st_mtime)
                        expect = struct.pack('<4sl',
                                             interpreter.magic_number(version), mtime)
                        with open(cfn, 'rb') as chandle:
                            actual = chandle.read(8)
                        if expect == actual:
                            continue
                    except (IOError, OSError):
                        pass
                if pycache_dir not in skip_dirs and not exists(pycache_dir):
                    try:
                        mkdir(pycache_dir)
                    except Exception as e:
                        log.error("cannot create directory %s: %r", pycache_dir, e)
                        skip_dirs.add(pycache_dir)
                        continue
            pipe = STDINS[version]
            pipe.send(fn)


################################################################
def main():
    usage = '%prog [-V [X.Y][-][A.B]] DIR_OR_FILE [-X REGEXPR]\n' +\
        '       %prog -p PACKAGE'
    parser = optparse.OptionParser(usage, version='%prog 3.10.6-1~22.04.1',
                                   option_class=Option)
    parser.add_option('-v', '--verbose', action='store_true', dest='verbose',
                      help='turn verbose mode on')
    parser.add_option('-q', '--quiet', action='store_false', dest='verbose',
                      default=False, help='be quiet')
    parser.add_option('-f', '--force', action='store_true', dest='force',
                      default=False,
                      help='force rebuild even if timestamps are up-to-date')
    parser.add_option('-O', action='store_true', dest='optimize',
                      default=False, help="byte-compile to .pyo files")
    parser.add_option('-p', '--package',
                      help='specify Debian package name whose files should be bytecompiled')
    parser.add_option('-V', type='version_range', dest='vrange',
                      help="""force private modules to be bytecompiled
with Python version from given range, regardless of the default Python version
in the system.  If there are no other options, bytecompile all public modules
for installed Python versions that match given range.

VERSION_RANGE examples: '3.1' (version 3.1 only), '3.1-' (version 3.1 or
newer), '3.1-3.3' (version 3.1 or 3.2), '-4.0' (all supported 3.X versions)""")
    parser.add_option('-X', '--exclude', action='append',
                      dest='regexpr', type='regexpr',
                      help='exclude items that match given REGEXPR. \
You may use this option multiple times to build up a list of things to exclude.')

    (options, args) = parser.parse_args()

    if options.verbose or environ.get('PYCOMPILE_DEBUG') == '1':
        log.setLevel(logging.DEBUG)
        log.debug('argv: %s', sys.argv)
        log.debug('options: %s', options)
        log.debug('args: %s', args)
    else:
        log.setLevel(logging.WARN)

    if options.regexpr and not args:
        parser.error('--exclude option works with private directories '
                     'only, please use /usr/share/python3/bcep to specify '
                     'public modules to skip')

    if options.vrange and options.vrange[0] == options.vrange[1] and\
            options.vrange != (None, None) and\
            exists("/usr/bin/python%d.%d" % options.vrange[0]):
        # specific version requested, use it even if it's not in SUPPORTED
        versions = {options.vrange[0]}
    else:
        versions = get_requested_versions(options.vrange, available=True)
    if not versions:
        log.error('Requested versions are not installed')
        exit(3)

    if options.package and args:  # package's private directories
        # get requested Python version
        compile_versions = debsorted(versions)[:1]
        log.debug('compile versions: %s', versions)

        pkg_files = tuple(dpf.from_package(options.package))
        for item in args:
            e_patterns = get_exclude_patterns(item, options.regexpr,
                                              compile_versions)
            if not exists(item):
                log.warning('No such file or directory: %s', item)
            else:
                log.debug('byte compiling %s using Python %s',
                          item, compile_versions)
                files = dpf.filter_directory(pkg_files, item)
                compile(files, compile_versions, options.force,
                        options.optimize, e_patterns)
    elif options.package:  # package's public modules
        # no need to limit versions here, it's either pyr mode or version is
        # hardcoded in path / via -V option
        e_patterns = get_exclude_patterns()
        files = dpf.from_package(options.package)
        files = dpf.filter_public(files, versions)
        compile(files, versions,
                options.force, options.optimize, e_patterns)
    elif args:  # other directories/files
        for item in args:
            e_patterns = get_exclude_patterns(item, options.regexpr, versions)
            files = dpf.from_directory(item)
            compile(files, versions,
                    options.force, options.optimize, e_patterns)
    else:
        parser.print_usage()
        exit(1)

    # wait for all processes to finish
    rv = 0
    for process in WORKERS.values():
        process.communicate()
        if process.returncode not in (None, 0):
            rv = process.returncode
    exit(rv)

if __name__ == '__main__':
    main()