#!/usr/bin/python

from __future__ import print_function

import argparse
import bugzilla
import dateutil.parser
from datetime import timedelta, datetime
from dateutil.tz import tzlocal
import os
import requests.exceptions
import subprocess
import sys
import tempfile
import yaml
from xml.etree import cElementTree as ET

import osc.conf
import osc.core

from osclib.cache import Cache

# Issue summary can contain unicode characters and therefore a string containing
# either summary or one in which ISSUE_SUMMARY is then placed must be unicode.
# For example, translation-update-upstream contains bsc#877707 which has a
# unicode character in its summary.
BUG_SUMMARY = 'Missing issue references from {project}/{package} in {factory}/{package}'
BUG_TEMPLATE = u'{message_start}\n\n{issues}'
MESSAGE_START = 'The following issues were referenced in the changelog for {project}/{package}, but where not found in {factory}/{package} after {newest} days. Review the issues and submit changes to {factory} to ensure all relevant changes end up in {factory} which is used as the basis for the next SLE version. For more information and details on how to go about submitting the changes see https://mailman.suse.de/mlarch/SuSE/research/2017/research.2017.02/msg00051.html.'
ISSUE_SUMMARY = u'[{label}]({url}) owned by {owner}: {summary}'
ISSUE_SUMMARY_PLAIN = u'[{label}]({url})'


def bug_create(bugzilla_api, meta, assigned_to, cc, summary, description):
    createinfo = bugzilla_api.build_createbug(
        product=meta[0],
        component=meta[1],
        version=meta[2],
        severity='normal',
        op_sys='Linux',
        platform='PC',
        assigned_to=assigned_to,
        cc=cc,
        summary=summary,
        description=description)
    newbug = bugzilla_api.createbug(createinfo)

    return newbug.id

def user_email(apiurl, userid):
    url = osc.core.makeurl(apiurl, ('person', userid))
    root = ET.parse(osc.core.http_GET(url)).getroot()
    email = root.find('email')
    return email.text if email is not None else None

def bug_owner(apiurl, package):
    query = {
        'binary': package,
    }
    url = osc.core.makeurl(apiurl, ('search', 'owner'), query=query)
    root = ET.parse(osc.core.http_GET(url)).getroot()

    bugowner = root.find('.//person[@role="bugowner"]')
    if bugowner is not None:
        return user_email(apiurl, bugowner.get('name'))
    maintainer = root.find('.//person[@role="maintainer"]')
    if maintainer is not None:
        return user_email(apiurl, maintainer.get('name'))

    return None

def bug_meta_get(bugzilla_api, bug_id):
    bug = bugzilla_api.getbug(bug_id)
    return (bug.product, bug.component, bug.version)

def bug_meta(bugzilla_api, defaults, trackers, issues):
    # Extract meta from the first bug from bnc tracker or fallback to defaults.
    prefix = trackers['bnc'][:3]
    for issue in issues:
        if issue.startswith(prefix):
            return bug_meta_get(bugzilla_api, issue[4:])

    return defaults

def bugzilla_init(apiurl):
    bugzilla_api = bugzilla.Bugzilla(apiurl)
    if not bugzilla_api.logged_in:
        print('Bugzilla credentials required to create bugs.')
        bugzilla_api.interactive_login()
    return bugzilla_api

def prompt_continue(change_count):
    allowed = ['y', 'b', 's', 'n', '']
    if change_count > 0:
        print('File bug for {} issues and continue? [y/b/s/n/?] (y): '.format(change_count), end='')
    else:
        print('No changes for which to create bug, continue? [y/b/s/n/?] (y): ', end='')

    response = raw_input().lower()
    if response == '?':
        print('b = break; file bug if applicable, record in db, and stop\ns = skip package')
    elif response in allowed:
        if response == '':
            response = 'y'
        return response
    else:
        print('Invalid response: {}'.format(response))

    return prompt_continue(change_count)

def prompt_interactive(changes, project, package):
    with tempfile.NamedTemporaryFile(suffix='.yml') as temp:
        temp.write(yaml.safe_dump(changes, default_flow_style=False, default_style="'") + '\n')
        temp.write('# {}/{}\n'.format(project, package))
        temp.write('# comment or remove lines to whitelist issues')
        temp.flush()

        editor = os.getenv('EDITOR')
        if not editor:
            editor = 'xdg-open'
        subprocess.call([editor, temp.name])

        changes_after = yaml.safe_load(open(temp.name).read())
        if changes_after is None:
            changes_after = {}

        return changes_after

def issue_found(package, label, db):
    return not(package not in db or db[package] is None or label not in db[package])

def issue_trackers(apiurl):
    url = osc.core.makeurl(apiurl, ['issue_trackers'])
    root = ET.parse(osc.core.http_GET(url)).getroot()
    trackers = {}
    for tracker in root.findall('issue-tracker'):
        trackers[tracker.find('name').text] = tracker.find('label').text
    return trackers

def issue_normalize(trackers, tracker, name):
    if tracker in trackers:
        return trackers[tracker].replace('@@@', name)
    raise Exception('unkown tracker {} for {}'.format(tracker, name))

def issues_get(apiurl, project, package, trackers, db):
    issues = {}

    url = osc.core.makeurl(apiurl, ['source', project, package], {'view': 'issues'})
    root = ET.parse(osc.core.http_GET(url)).getroot()

    now = datetime.now(tzlocal()) # Much harder than should be.
    for issue in root.findall('issue'):
        # Normalize issues to active API instance issue-tracker definitions.
        # Assumes the two servers have the name trackers, but different labels.
        label = issue_normalize(trackers, issue.find('tracker').text, issue.find('name').text)

        # Ignore already processed issues.
        if issue_found(package, label, db):
            continue

        summary = issue.find('summary')
        if summary is not None:
            summary = summary.text

        owner = issue.find('owner/email')
        if owner is not None:
            owner = owner.text

        created = issue.find('created_at')
        updated = issue.find('updated_at')
        if created is not None and created.text is not None:
            date = created.text
        elif updated is not None and updated.text is not None:
            date = updated.text
        else:
            # Old date to make logic work.
            date = '2007-12-12 00:00 GMT+1'

        date = dateutil.parser.parse(date)
        delta = now - date

        issues[label] = {
            'url': issue.find('url').text,
            'summary': summary,
            'owner': owner,
            'age': delta.days,
        }

    return issues

def package_list(apiurl, project):
    url = osc.core.makeurl(apiurl, ['source', project], { 'expand': 1 })
    root = ET.parse(osc.core.http_GET(url)).getroot()

    packages = []
    for package in root.findall('entry'):
        packages.append(package.get('name'))

    return sorted(packages)

def git_clone(url, directory):
    return_code = subprocess.call(['git', 'clone', url, directory])
    if return_code != 0:
        raise Exception('Failed to clone {}'.format(url))

def sync(config_dir, db_dir):
    cwd = os.getcwd()
    devnull = open(os.devnull, 'wb')

    git_sync_dir = os.path.join(config_dir, 'git-sync')
    git_sync_exec = os.path.join(git_sync_dir, 'git-sync')
    if not os.path.exists(git_sync_dir):
        os.makedirs(git_sync_dir)
        git_clone('https://github.com/simonthum/git-sync.git', git_sync_dir)
    else:
        os.chdir(git_sync_dir)
        subprocess.call(['git', 'pull', 'origin', 'master'], stdout=devnull, stderr=devnull)

    if not os.path.exists(db_dir):
        os.makedirs(db_dir)
        git_clone('<EMAIL>:jberry-suse/osc-plugin-factory-issue-db.git', db_dir)

        os.chdir(db_dir)
        subprocess.call(['git', 'config', '--bool', 'branch.master.sync', 'true'])
        subprocess.call(['git', 'config', '--bool', 'branch.master.syncNewFiles', 'true'])
        subprocess.call(['git', 'config', 'branch.master.syncCommitMsg', 'Sync issue-diff.py changes.'])

    os.chdir(db_dir)
    return_code = subprocess.call([git_sync_exec])
    if return_code != 0:
        raise Exception('Failed to sync local db changes.')

    os.chdir(cwd)

def main(args):
    # Store the default apiurl in addition to the overriden url if the
    # option was set and thus overrides the default config value.
    # Using the OBS link does not work for ?view=issues.
    if args.apiurl is not None:
        osc.conf.get_config()
        apiurl_default = osc.conf.config['apiurl']
    else:
        apiurl_default = None

    osc.conf.get_config(override_apiurl=args.apiurl)
    osc.conf.config['debug'] = args.debug
    apiurl = osc.conf.config['apiurl']

    Cache.init()

    db_dir = os.path.join(args.config_dir, 'issue-db')
    db_file = os.path.join(db_dir, '{}.yml'.format(args.project))
    sync(args.config_dir, db_dir)

    if os.path.exists(db_file):
        db = yaml.safe_load(open(db_file).read())
        if db is None:
            db = {}
        else:
            print('Loaded db file: {}'.format(db_file))
    else:
        db = {}

    print('Comparing {} against {}'.format(args.project, args.factory))

    bugzilla_api = bugzilla_init(args.bugzilla_apiurl)
    bugzilla_defaults = (args.bugzilla_product, args.bugzilla_component, args.bugzilla_version)

    trackers = issue_trackers(apiurl)
    packages_project = package_list(apiurl, args.project)
    packages_factory = package_list(apiurl_default, args.factory)
    packages = set(packages_project).intersection(set(packages_factory))
    new = 0
    for package in sorted(packages):
        issues_project = issues_get(apiurl, args.project, package, trackers, db)
        issues_factory = issues_get(apiurl_default, args.factory, package, trackers, db)

        missing_from_factory = set(issues_project.keys()) - set(issues_factory.keys())

        # Filtering by age must be done after set diff in order to allow for
        # matches with issues newer than --newest.
        for label in set(missing_from_factory):
            if issues_project[label]['age'] < args.newest:
                missing_from_factory.remove(label)

        if len(missing_from_factory) == 0:
            continue

        print('{}: {} missing'.format(package, len(missing_from_factory)))

        # Generate summaries for issues missing from factory.
        changes = {}
        for issue in missing_from_factory:
            info = issues_project[issue]
            summary = ISSUE_SUMMARY if info['owner'] is not None else ISSUE_SUMMARY_PLAIN
            changes[issue] = summary.format(
                label=issue, url=info['url'], owner=info['owner'], summary=info['summary'])

        # Prompt user to decide which issues to whitelist.
        changes_after = prompt_interactive(changes, args.project, package)

        # Determine if any real changes (vs typos) and create text issue list.
        issues = []
        cc = []
        if len(changes_after) > 0:
            for issue, summary in changes.items():
                if issue in changes_after:
                    issues.append('- ' + summary)
                    owner = issues_project[issue]['owner']
                    if owner is not None:
                        cc.append(owner)

        # Prompt user about how to continue.
        response = prompt_continue(len(issues))
        if response == 'n':
            break
        if response == 's':
            continue

        # File a bug if not all issues whitelisted.
        if len(issues) > 0:
            summary = BUG_SUMMARY.format(project=args.project, factory=args.factory, package=package)
            message = BUG_TEMPLATE.format(
                message_start=MESSAGE_START.format(
                    project=args.project, factory=args.factory, package=package, newest=args.newest),
                issues='\n'.join(issues))

            # Determine bugzilla meta information to use when creating bug.
            meta = bug_meta(bugzilla_api, bugzilla_defaults, trackers, changes.keys())
            owner = bug_owner(apiurl, package)
            if args.bugzilla_cc:
                cc.append(args.bugzilla_cc)
            bug_id = bug_create(bugzilla_api, meta, owner, cc, summary, message)

        # Mark changes in db.
        notified, whitelisted = 0, 0
        for issue in changes:
            if package not in db:
                db[package] = {}

            if issue in changes_after:
                db[package][issue] = str(bug_id)
                notified += 1
            else:
                db[package][issue] = 'whitelist'
                whitelisted += 1

        # Write out changes after each package to avoid loss.
        with open(db_file, 'w') as outfile:
            yaml.safe_dump(db, outfile, default_flow_style=False, default_style="'")

        if notified > 0:
            print('{}: {} notified in bug #{}, {} whitelisted'.format(package, notified, bug_id, whitelisted))
        else:
            print('{}: {} whitelisted'.format(package, whitelisted))

        if response == 'b':
            break

        new += 1
        if new == args.limit:
            print('stopped at limit')
            break

    sync(args.config_dir, db_dir)


if __name__ == '__main__':
    description = 'Compare packages from a project against factory for differences in referenced issues and ' \
                  'present changes to allow whitelisting before creating bugzilla entries. A database is kept ' \
                  'of previously handled issues to avoid repeats and kept in sync via a git repository.'
    parser = argparse.ArgumentParser(description=description)
    parser.add_argument('-A', '--apiurl', default='https://api.suse.de', metavar='URL', help='OBS instance API URL')
    parser.add_argument('--bugzilla-apiurl', required=True, metavar='URL', help='bugzilla API URL')
    parser.add_argument('--bugzilla-product', default='SUSE Linux Enterprise Desktop 12 SP2', metavar='PRODUCT', help='default bugzilla product')
    parser.add_argument('--bugzilla-component', default='Other', metavar='COMPONENT', help='default bugzilla component')
    parser.add_argument('--bugzilla-version', default='GM', metavar='VERSION', help='default bugzilla version')
    parser.add_argument('--bugzilla-cc', metavar='EMAIL', help='bugzilla address added to cc on all bugs created')
    parser.add_argument('-d', '--debug', action='store_true', help='print info useful for debugging')
    parser.add_argument('-f', '--factory', default='openSUSE:Factory', metavar='PROJECT', help='factory project to use as baseline for comparison')
    parser.add_argument('-p', '--project', default='SUSE:SLE-12-SP3:GA', metavar='PROJECT', help='project to check for issues that have are not found in factory')
    parser.add_argument('--newest', type=int, default='30', metavar='AGE_IN_DAYS', help='newest issues to be considered')
    parser.add_argument('--limit', type=int, default='0', help='limit number of packages with new issues processed')
    parser.add_argument('--config-dir', help='configuration directory containing git-sync tool and issue db')
    args = parser.parse_args()

    if args.config_dir is None:
        args.config_dir = os.path.expanduser('~/.osc-plugin-factory')

    sys.exit(main(args))
