from urllib3 import PoolManager
import json
import sys
import re


def get_patches(bugzillaID):
    http = PoolManager()

    # first find when the bug was fixed
    history = 'https://bugzilla.mozilla.org/rest/bug/{}/history'.format(
        bugzillaID)
    request = http.request('GET', history, retries=10)
    j = json.loads(request.data)
    times = [change['when'] for change in j['bugs'][0]['history']
             if "FIXED" in [c["added"] for c in change["changes"]]]

    # then look through all the fix comments for patch URLs
    comments = 'https://bugzilla.mozilla.org/rest/bug/{}/comment'.format(
        bugzillaID)
    request = http.request('GET', comments, retries=10)
    j = json.loads(request.data)
    urlregex = r'https?://hg\.mozilla\.org/(?:mozilla-central|releases/[^/]+)'\
        '/rev/[0-9a-f]+'
    fix_comments = [comment for comment in j['bugs'][bugzillaID]['comments']
                    if comment['creation_time'] in times]
    for comment in fix_comments:
        for urlmatch in re.findall(urlregex, comment['text']):
            patch_url = urlmatch.replace('/rev/', '/raw-rev/')
            yield http.request('GET', patch_url, retries=10).data.decode(
                errors='ignore')


def get_title_lines(bugzillaID):
    for patch in get_patches(bugzillaID):
        for line in patch.split('\n'):
            line = line.strip()
            if len(line) != 0 and line[0] != '#':
                yield line
                break


def get_affected_files(bugzillaID):
    for patch in get_patches(bugzillaID):
        for line in patch.split('\n'):
            if len(line) > 5 and (
                    line[:5] == '--- a' or
                    line[:5] == '+++ b'):
                yield line[6:]


def get_deleted_files(bugzillaID):
    fetch_next = False
    for patch in get_patches(bugzillaID):
        for line in patch.split('\n'):
            if len(line) >= 17 and \
               line[:17] == "deleted file mode" and \
               not fetch_next:
                fetch_next = True
            elif fetch_next:
                assert(line[:5] == '--- a')
                yield line[6:]
                fetch_next = False


if __name__ == '__main__':
    command = sys.argv[1]
    bugzillaID = sys.argv[2]
    if command == 'titles':
        line_generator = get_title_lines(bugzillaID)
    elif command == 'files':
        line_generator = get_affected_files(bugzillaID)
    elif command == 'deleted':
        line_generator = get_deleted_files(bugzillaID)
    else:
        print("Bad command: " + command)
        sys.exit(1)
    for item in line_generator:
        print(item)