#!/usr/bin/env {{ python }}

import os
import re
import subprocess
import sys

TOPLEVEL = subprocess.run(['git', 'rev-parse', '--show-toplevel'], encoding='utf-8', capture_output=True, check=True).stdout.strip()

LOCATION = os.path.join(TOPLEVEL, r'{{ location }}')
SPACING = 8
IDENT = 4
SCRIPTS = os.path.dirname(os.path.dirname(LOCATION))
PREPARE_CHANGELOG_CMD = [{{ perl }}, os.path.join(SCRIPTS, 'prepare-ChangeLog'), '--no-write', '--only-files', '--delimiters', '--git-index']
CHERRY_PICKING_RE = re.compile(r'^# You are currently cherry-picking commit (?P<hash>[a-f0-9A-F]+)\.$')
CHERRY_PICK_COMMIT_RE = re.compile(r'^(?P<a>\S+)( \((?P<b>\S+)\))?$')
REFNAME_RE = re.compile(r'^refs/remotes/(?P<remote>[^/ ]+)/(?P<branch>\S+)$')
HASH_RE = re.compile(r'^[a-f0-9A-F]+$')
IDENTIFIER_RE = re.compile(r'(\d+\.)?\d+@\S+')
PREFER_RADAR = {{ prefer_radar }}

DEFAULT_BRANCH = '{{ default_branch }}'
SOURCE_REMOTES = {{ source_remotes }}
TRAILERS_TO_STRIP = {{ trailers_to_strip }}

COMMIT_REF_BASE = r'r?R?[a-f0-9A-F]+(\.\d+)?@?([0-9a-zA-z\-\/\.]+[0-9a-zA-z\-\/])?'
COMPOUND_COMMIT_REF = r'(?P<primary>{})(?P<secondary> \({}\))?'.format(COMMIT_REF_BASE, COMMIT_REF_BASE)
CHERRY_PICK_RE = [
    re.compile(r'\S* ?[Cc]herry[- ][Pp]ick of {}'.format(COMPOUND_COMMIT_REF)),
    re.compile(r'\S* ?[Cc]herry[- ][Pp]ick {}'.format(COMPOUND_COMMIT_REF)),
    re.compile(r'\S* ?[Cc]herry[- ][Pp]icked {}'.format(COMPOUND_COMMIT_REF)),
]
UNPACK_SECONDARY_RE = re.compile(r' \(({})\)'.format(COMMIT_REF_BASE))

sys.path.append(SCRIPTS)
from webkitpy.common.checkout.diff_parser import DiffParser
from webkitbugspy import radar


def set_env_variables_from_branch_config():
    BRANCH = subprocess.run(['git', 'rev-parse', '--abbrev-ref', 'HEAD'], encoding='utf-8', capture_output=True, check=True).stdout.strip()
    for name, data in dict(
        title=('COMMIT_MESSAGE_TITLE', 1),
        bug=('COMMIT_MESSAGE_BUG', re.compile(r'^(\D+)\d+$')),
        cherry_picked=('GIT_WEBKIT_CHERRY_PICKED', 1),
    ).items():
        variable, mode = data
        if variable in os.environ and os.environ[variable]:
            continue
        try:
            value = ''
            count = 0
            for line in reversed(subprocess.run(
                ['git', 'config', '--get-all', 'branch.{}.{}'.format(BRANCH, name)],
                capture_output=True,
                encoding='utf-8',
                check=True
            ).stdout.strip().splitlines()):
                if isinstance(mode, int) and count >= mode:
                    break
                elif isinstance(mode, re.Pattern):
                    match = mode.match(line)
                    if match and match.group(1) in value:
                        continue

                if line:
                    value += line + '\n'
                    count += 1

            value = value.strip()
            if value:
                os.environ[variable] = value
        except subprocess.CalledProcessError as error:
            # `1` means that key did not exist, which is valid.
            if error.returncode != 1:
                sys.stderr.write(error.stderr)

def get_bugs_string():
    """Determines what bug URLs to fill or suggest in a WebKit commit message."""
    need_the_bug_url = 'Need the bug URL (OOPS!).'
    need_the_radar = 'Include a Radar link (OOPS!).'
    has_radar = any([bool(regex.match(line))
                     for line in os.environ.get('COMMIT_MESSAGE_BUG', '').splitlines()
                     for regex in radar.Tracker.RES])

    if os.environ.get('COMMIT_MESSAGE_BUG'):
        if has_radar or not bool(radar.Tracker.radarclient()):
            return os.environ['COMMIT_MESSAGE_BUG']
        else:
            return os.environ['COMMIT_MESSAGE_BUG'] + '\n' + need_the_radar

    bugs_string = need_the_bug_url
    if bool(radar.Tracker.radarclient()):
        bugs_string += '\n' + need_the_radar
    return bugs_string

def parseChanges(command, commit_message):
    dirname = None
    changes = []

    try:
        for line in subprocess.run(
            command,
            encoding='utf-8',
            capture_output=True,
            check=True
        ).stdout.splitlines():
            if line == '~':
                dirname = None
                continue
            if line.startswith(' ' * SPACING):
                if dirname:
                    line = line.replace('* ', '* {}/'.format(dirname))
                commit_message.append(line[SPACING:])
                changes.append(line[SPACING:])
                continue
            if line.endswith(':'):
                dirname = line.split(':')[0]
                continue
    except subprocess.CalledProcessError:
        commit_message.append('')
        return
    return changes

def message(source=None, sha=None):
    commit_message = []
    amend_changes = None
    command = PREPARE_CHANGELOG_CMD

    if sha:
        commit_message.append('Amend changes:')
        amend_changes = parseChanges(command, commit_message)
        commit_message.append('')

        commit_message.append('Combined changes:')
        command += ['--git-commit', 'HEAD']

    combined_changes = parseChanges(command, commit_message)

    revert_msg = os.environ.get('COMMIT_MESSAGE_REVERT', '')
    if revert_msg:
        return '''{title}\n{revert}'''.format(
            title=os.environ.get('COMMIT_MESSAGE_TITLE', ''),
            revert=revert_msg,
        ), combined_changes, amend_changes
    else:
        bugs_string = get_bugs_string()
        return '''{title}
{bugs}

Reviewed by NOBODY (OOPS!).

Explanation of why this fixes the bug (OOPS!).

{content}
'''.format(
        title=os.environ.get('COMMIT_MESSAGE_TITLE', '') or 'Need a short description (OOPS!).',
        bugs=bugs_string,
        content='\n'.join(commit_message) + os.environ.get('COMMIT_MESSAGE_CONTENT', ''),
    ), combined_changes, amend_changes

def source_branches():
    proc = None
    try:
        proc = subprocess.Popen(
            ['git', 'rev-list', 'HEAD'],
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            encoding='utf-8',
        )
        outer_line = proc.stdout.readline()
        while outer_line:
            branches = set()
            for inner_line in subprocess.run(
                ['git', 'branch', '--contains', outer_line.strip(), '-a', '--format', '%(refname)'],
                encoding='utf-8',
                capture_output=True,
                check=True
            ).stdout.splitlines():
                if not inner_line.startswith('refs/remotes'):
                    continue
                _, _, remote, branch = inner_line.split('/', 3)
                if remote in SOURCE_REMOTES and branch != 'HEAD':
                    branches.add(branch)
            if branches:
                return sorted(branches)
            outer_line = proc.stdout.readline()
    finally:
        if proc and proc.poll() is None:
            proc.kill()

    return []

def cherry_pick(content):
    cherry_picked = os.environ.get('GIT_WEBKIT_CHERRY_PICKED')
    bugs = os.environ.get('COMMIT_MESSAGE_BUG', '').splitlines()
    bug = bugs[0] if bugs else None

    if PREFER_RADAR and not bug:
        RADAR_RES = [
            re.compile(r'<?rdar://problem/(?P<id>\d+)>?'),
            re.compile(r'<?radar://problem/(?P<id>\d+)>?'),
            re.compile(r'<?rdar:\/\/(?P<id>\d+)>?'),
            re.compile(r'<?radar:\/\/(?P<id>\d+)>?'),
        ]
        seen_empty = False
        for line in content.splitlines():
            if not line and seen_empty:
                break
            elif not line:
                seen_empty = True
                continue
            words = line.split()
            for word in [words[0], words[-1]] if words[0] != words[-1] else [words[0]]:
                for regex in RADAR_RES:
                    if regex.match(word):
                        bug = word
                        break
                if bug:
                    break

    if not cherry_picked or not bug:
        LINK_RE = re.compile(r'^\S+:\/\/\S+\d+\S*$')

        last_line = ''
        for line in content.splitlines():
            if not line:
                continue
            if not line.startswith('#'):
                last_line = line
            if not bug and LINK_RE.match(line):
                bug = line
            match = None if cherry_picked else CHERRY_PICKING_RE.match(line)
            if match:
                cherry_picked = match.group('hash')

            if bug and cherry_picked:
                break

        if last_line and (not cherry_picked or not IDENTIFIER_RE.search(cherry_picked)):
            from_last_line = IDENTIFIER_RE.search(last_line)
            if from_last_line and not cherry_picked:
                cherry_picked = from_last_line.group(0)
            elif from_last_line:
                cherry_picked = '{} ({})'.format(from_last_line.group(0), cherry_picked)

    production_hash = None
    match = CHERRY_PICK_COMMIT_RE.match(cherry_picked)
    for candidate in ([match.group('a'), match.group('b')] if match else []):
        if not candidate:
            continue
        if HASH_RE.match(candidate):
            production_hash = candidate

    if production_hash:
        try:
            subprocess.run(
                ['git', 'merge-base', '--is-ancestor', production_hash, DEFAULT_BRANCH],
                encoding='utf-8', check=True
            )
        except subprocess.CalledProcessError:
            remotes = set()
            for line in subprocess.run(
                ['git', 'branch', '--contains', production_hash, '-a', '--format', '%(refname)'],
                encoding='utf-8',
                capture_output=True,
                check=True
            ).stdout.splitlines():
                match = REFNAME_RE.match(line.strip())
                if not match:
                    continue
                remote = match.group('remote')
                if remote in SOURCE_REMOTES:
                    remotes.add(match.group('remote'))
            if not remotes:
                production_hash = None

    is_trunk_bound = DEFAULT_BRANCH in source_branches()
    in_suffix = False
    result = []
    unindent = False

    lines = list(content.splitlines())
    for header in CHERRY_PICK_RE:
        match = header.match(lines[0])
        if not match:
            continue
        cherry_picked = '{}{}'.format(match.group('primary'), match.group('secondary') or '')
        unindent = True
        lines = lines[1:]
        while not lines[0].rstrip():
            lines = lines[1:]
        break

    cherry_pick_metadata = '{}. {}'.format(cherry_picked or '???', bug or '<bug>')
    if not is_trunk_bound:
        result += ['Cherry-pick {}'.format(cherry_pick_metadata), '']

    for line in lines:
        line = line.rstrip()
        if not line:
            result.append('')
            continue
        if unindent and line.startswith(IDENT*' '):
            line = line[IDENT:]

        if line[0] == '#' and not in_suffix:
            in_suffix = True
            if is_trunk_bound and production_hash:
                while len(result) and not result[-1] or (result[-1].split(':', 1)[0] in TRAILERS_TO_STRIP):
                    del result[-1]
                result += ['', 'Originally-landed-as: {}'.format(cherry_pick_metadata)]
        if line[0] != '#' and not is_trunk_bound and production_hash:
            result.append(IDENT*' ' + line)
        else:
            result.append(line)
    return '\n'.join(result)

def annotate_deleted_lines(amend_changes, combined_changes):
    annotated_lines = []
    for line in amend_changes:
        if line not in combined_changes:
            if line.startswith('*'):
                if not line.endswith('Removed.'):
                    line += ' Removed.'
            elif not line.endswith('Deleted.'):
                line += ' Deleted.'
        annotated_lines.append(line)
    return annotated_lines

def amended_message(full_message, combined_changes, amend_changes, update_changelog):
    if amend_changes and update_changelog:
        try:
            from webkitscmpy.commit_parser import CommitMessageParser
        except ImportError as e:
            sys.stderr.write(f'{e}: Could not update changelog automatically. Falling back to the default template.\n')
        else:
            commit_message_parser = CommitMessageParser()
        commit_message_parser.parse_message(full_message)
        updated_changelog_lines = commit_message_parser.apply_comments_to_modified_files_lines(combined_changes)
        reviewed_by_lines = (commit_message_parser.reviewed_by_lines or ['Reviewed by NOBODY (OOPS!).'])
        description_lines = (commit_message_parser.description_lines or ['Explanation of why this fixes the bug (OOPS!).'])
        tests_lines = [commit_message_parser.tests_lines, ''] if commit_message_parser.tests_lines else []
        amended_message = commit_message_parser.title_lines + [''] + reviewed_by_lines + [''] + description_lines + [''] + tests_lines + updated_changelog_lines
        removed_changelog_lines = commit_message_parser.apply_comments_to_modified_files_lines(annotate_deleted_lines(amend_changes, combined_changes), return_deleted=True)
        return '''{message_body}

# Your changelog has been updated with the following files/functions:
{changed_lines}
# The following lines have been removed from the changelog:
{removed_lines}
# To temporarily disable this feature, run `git-webkit commit --amend --no-update`.
'''.format(message_body='\n'.join(amended_message),
        changed_lines='\n'.join([f'#    {file}' for file in amend_changes]),
        removed_lines='\n'.join([f'#    {file}' for file in removed_changelog_lines]))

    commit_message = full_message
    if not update_changelog:
        commit_message += '''
# To automatically update your changelog when amending, run `git-webkit setup`
# or `git-webkit commit --amend --update` for one-time use.
'''
    return commit_message

def main(file_name=None, source=None, sha=None):
    with open(file_name, 'r') as commit_message_file:
        content = commit_message_file.read()

    if source not in (None, 'commit', 'template', 'merge'):
        return 0

    if os.environ.get('COMMIT_MESSAGE_TITLE', '').startswith('Unreviewed, reverting'):
        pass
    elif source == 'merge' and content.startswith('Revert'):
        return 0
    else:
        set_env_variables_from_branch_config()

    for line in content.splitlines():
        if CHERRY_PICKING_RE.match(line):
            os.environ['GIT_REFLOG_ACTION'] = 'cherry-pick'
            break

    if source == 'merge' and os.environ.get('GIT_REFLOG_ACTION') == 'cherry-pick':
        with open(file_name, 'w') as commit_message_file:
            commit_message_file.write(cherry_pick(content))
        return 0

    if os.environ.get('GIT_EDITOR', '') == ':':
        # When there's no editor being launched, do nothing.
        return 0

    update_changelog = False
    # Allow for overrides with git-webkit commit --amend [--update/--no-update]
    if os.environ.get('WKSCMPY_UPDATE_CHANGELOG', '') == 'True':
        update_changelog = True
    elif os.environ.get('WKSCMPY_UPDATE_CHANGELOG', '') == 'False':
        update_changelog = False
    else:
        try:
            update_changelog = subprocess.run(
                ['git', 'config', '--get', '--type', 'bool', 'webkitscmpy.auto-update-changelog'],
                encoding='utf-8',
                capture_output=True,
                check=True
            ).stdout.strip()
            update_changelog = True if update_changelog == 'true' else False
        except subprocess.CalledProcessError as error:
            if error.returncode != 1:
                sys.stderr.write(error.stderr)

    with open(file_name, 'w') as commit_message_file:
        generated_msg, combined_changes, amend_changes = message(source=source, sha=sha)
        if sha:
            git_log_msg = subprocess.run(
                ['git', 'log', sha, '-1', '--pretty=format:%B'],
                encoding='utf-8',
                capture_output=True,
                check=True
            ).stdout
            commit_message_file.write(amended_message(git_log_msg, combined_changes, amend_changes, update_changelog))
        else:
            commit_message_file.write(generated_msg)

        commit_message_file.write('''
# Please populate the above commit message. Lines starting with '#'
# will be ignored. For any files or functions that don't have an
# associated comment, please remove them from the commit message.

''')
        if sha:
            for line in generated_msg.splitlines():
                commit_message_file.write('# {}\n'.format(line))
            commit_message_file.write('\n')
        for line in subprocess.run(
            ['git', 'status'],
            encoding='utf-8',
            capture_output=True,
            check=True
        ).stdout.splitlines():
            commit_message_file.write('# {}\n'.format(line))

    return 0


if __name__ == '__main__':
    sys.exit(main(*sys.argv[1:]))