#!/usr/bin/env python3
# Copyright (C) 2018 and later: Unicode, Inc. and others.
# License & terms of use: http://www.unicode.org/copyright.html
# Author: shane@unicode.org

import argparse
import itertools
import os
import re
import sys
import datetime

from enum import Enum
from collections import namedtuple
from git import Repo
from jira import JIRA

# singleCount = 0

ICUCommit = namedtuple("ICUCommit", ["issue_id", "commit"])

class CommitWanted(Enum):
    REQUIRED = 1
    OPTIONAL = 2
    FORBIDDEN = 3
    ERROR = 4

ICUIssue = namedtuple("ICUIssue", ["issue_id", "is_closed", "commit_wanted", "issue"])

# JIRA constants.

# TODO: clearly these should move into a config file of some sort.
# NB: you can fetch the resolution IDs by authenticating to JIRA and then viewing
# the URL given.

# constants for jira_issue.fields.resolution.id
# <https://unicode-org.atlassian.net/rest/api/2/resolution>
R_NEEDS_MOREINFO        = "10003"
R_FIXED                 = "10004"
R_DUPLICATE             = "10006"
R_OUTOFSCOPE            = "10008"
R_ASDESIGNED            = "10009"
R_WONTFIX               = "10010"  # deprecated
R_INVALID               = "10012"
R_FIXED_BY_OTHER_TICKET = "10015"
R_NOTREPRO              = "10024"
R_FIXED_NON_REPO        = "10025"
R_FIX_SURVEY_TOOL       = "10022"
R_OBSOLETE              = "10023"

# constants for jira_issue.fields.issuetype.id
# <https://unicode-org.atlassian.net/rest/api/2/issuetype>
I_ICU_USERGUIDE         = "10010"
I_TASK                  = "10003"

# constants for jira_issue.fields.status.id
# <https://unicode-org.atlassian.net/rest/api/2/status>
S_REVIEWING             = "10001"
S_DONE                  = "10002"
S_REVIEW_FEEDBACK       = "10003"

def jira_issue_under_review(jira_issue):
    """
    Yields True if ticket is considered "under review"
    """
    # TODO: should be data driven from a config file.
    if jira_issue.issue.fields.status.id in [S_REVIEWING, S_REVIEW_FEEDBACK]:
        return True
    else:
        return False

def make_commit_wanted(jira_issue):
    """Yields a CommitWanted enum with the policy decision for this particular issue"""
    # TODO: should be data driven from a config file.
    if not jira_issue.fields.resolution:
        commit_wanted = CommitWanted["OPTIONAL"]
    elif jira_issue.fields.resolution.id in [ R_DUPLICATE, R_ASDESIGNED, R_OUTOFSCOPE, R_NOTREPRO, R_INVALID, R_NEEDS_MOREINFO, R_OBSOLETE ]:
        commit_wanted = CommitWanted["FORBIDDEN"]
    elif jira_issue.fields.resolution.id in [ R_FIXED_NON_REPO, R_FIX_SURVEY_TOOL, R_FIXED_BY_OTHER_TICKET ]:
        commit_wanted = CommitWanted["FORBIDDEN"]
    elif jira_issue.fields.resolution.id in [ R_FIXED ]:
        commit_wanted = CommitWanted["REQUIRED"]
    elif jira_issue.fields.resolution.id == R_FIXED_BY_OTHER_TICKET:
        commit_wanted = CommitWanted["FORBIDDEN"]
    elif jira_issue.fields.resolution.id != R_FIXED:
        commit_wanted = CommitWanted["ERROR"]
    elif jira_issue.fields.issuetype.id in [ I_ICU_USERGUIDE, I_TASK ]:
        commit_wanted = CommitWanted["OPTIONAL"]
    else:
        commit_wanted = CommitWanted["REQUIRED"]
    return commit_wanted


flag_parser = argparse.ArgumentParser(
    description = "Generates a Markdown report for commits on master since the 'latest' tag.",
    formatter_class = argparse.ArgumentDefaultsHelpFormatter
)
flag_parser.add_argument(
    "--rev-range",
    help = "A git revision range; see https://git-scm.com/docs/gitrevisions. Should be the two-dot range between the previous release and the current tip.",
    required = True
)
flag_parser.add_argument(
    "--repo-root",
    help = "Path to the repository to check",
    default = os.path.join(os.path.dirname(__file__), "..", "..")
)
flag_parser.add_argument(
    "--jira-hostname",
    help = "Hostname of the Jira instance",
    default = "unicode-org.atlassian.net"
)
flag_parser.add_argument(
    "--jira-username",
    help = "Username to use for authenticating to Jira",
    default = os.environ.get("JIRA_USERNAME", None)
)
flag_parser.add_argument(
    "--jira-password",
    help = "Password to use for authenticating to Jira. Authentication is necessary to process sensitive tickets. Leave empty to skip authentication. Instead of passing your password on the command line, you can save your password in the JIRA_PASSWORD environment variable. You can also create a file in this directory named \".env\" with the contents \"JIRA_PASSWORD=xxxxx\".",
    default = os.environ.get("JIRA_PASSWORD", None)
)
flag_parser.add_argument(
    "--jira-query",
    help = "JQL query load tickets; this should match tickets expected to correspond to the commits being checked. Example: 'project=ICU and fixVersion=63.1'; set fixVersion to the upcoming version.",
    required = True
)
flag_parser.add_argument(
    "--github-url",
    help = "Base URL of the GitHub repo",
    default = "https://github.com/unicode-org/icu"
)
flag_parser.add_argument(
    "--nocopyright",
    help = "Omit ICU copyright",
    action = "store_true"
)


def issue_id_to_url(issue_id, jira_hostname, **kwargs):
    return "https://%s/browse/%s" % (jira_hostname, issue_id)


def pretty_print_commit(commit, github_url, **kwargs):
    print("- %s `%s`" % (commit.commit.hexsha[:7], commit.commit.summary))
    print("\t- Authored by %s <%s>" % (commit.commit.author.name, commit.commit.author.email))
    print("\t- Committed at %s" % commit.commit.committed_datetime.isoformat())
    print("\t- GitHub Link: %s" % "%s/commit/%s" % (github_url, commit.commit.hexsha))


def pretty_print_issue(issue, type=None, **kwargs):
    print("- %s: `%s`" % (issue.issue_id, issue.issue.fields.summary))
    if type:
        print("\t- _%s_" % type)
    if issue.issue.fields.assignee:
        print("\t- Assigned to %s" % issue.issue.fields.assignee.displayName)
    else:
        print("\t- No assignee!")
    print("\t- Jira Link: %s" % issue_id_to_url(issue.issue_id, **kwargs))
    print("\t- Status: %s" % issue.issue.fields.status.name)
    if(issue.issue.fields.resolution):
        print("\t- Resolution: " + issue.issue.fields.resolution.name)
    if(issue.issue.fields.fixVersions):
        for version in issue.issue.fields.fixVersions:
            print("\t- Fix Version: " + version.name)
    else:
        print("\t- Fix Version: _none_")
    if issue.issue.fields.components and len(issue.issue.fields.components) > 0:
        print("\t- Component(s): " + (' '.join(sorted([str(component.name) for component in issue.issue.fields.components]))))

def get_commits(repo_root, rev_range, **kwargs):
    """
    Yields an ICUCommit for each commit in the user-specified rev-range.
    """
    repo = Repo(repo_root)
    for commit in repo.iter_commits(rev_range):
        match = re.search(r"^(\w+-\d+) ", commit.message)
        if match:
            issue_id = match.group(1)
            # print("@@@ %s = %s / %s" % (issue_id, commit, commit.summary), file=sys.stderr)
            yield ICUCommit(issue_id, commit)
        else:
            yield ICUCommit(None, commit)

def get_cherrypicked_commits(repo_root, rev_range, **kwargs):
    """
    Yields a set of commit SHAs (strings) that should be EXCLUDED from
    "missing jira" consideration, because they have already been cherry-picked onto the maint branch.
    """
    repo = Repo(repo_root)
    [a, b] = splitRevRange(rev_range)
    branchCut = get_branchcut_sha(repo_root, rev_range)
    print ("## git cherry %s %s %s (branch cut)" % (a, b, branchCut), file=sys.stderr)
    cherries = repo.git.cherry(a, b, branchCut)
    lns = cherries.split('\n')
    excludeThese = set()
    for ln in lns:
        [symbol, sha] = ln.split(' ')
        if(symbol == '-'):
            # print("Exclude: %s" % sha, file=sys.stderr)
            excludeThese.add(sha)
    print("## Collected %d commit(s) to exclude" % len(excludeThese))
    return excludeThese

def splitRevRange(rev_range):
    """
    Return the start and end of the revrange
    """
    return rev_range.split('..')

def get_branchcut_sha(repo_root, rev_range):
    """
    Return the sha of the 'branch cut', that is, the merge-base.
    Returns a git commit
    """
    repo = Repo(repo_root)
    [a, b] = splitRevRange(rev_range)
    return repo.merge_base(a, b)[0]

def get_jira_instance(jira_hostname, jira_username, jira_password, **kwargs):
    jira_url = "https://%s" % jira_hostname
    if jira_username and jira_password:
        jira = JIRA(jira_url, basic_auth=(jira_username, jira_password))
    else:
        jira = JIRA(jira_url)
    return (jira_url, jira)

def make_icu_issue(jira_issue):
    """Yields an ICUIssue for the individual jira object"""
    commit_wanted = make_commit_wanted(jira_issue)
    return ICUIssue(jira_issue.key, jira_issue.fields.status.id == S_DONE, commit_wanted, jira_issue)


def get_jira_issues(jira_query, **kwargs):
    """
    Yields an ICUIssue for each issue in the user-specified query.
    """
    jira_url, jira = get_jira_instance(**kwargs)
    # Jira limits us to query the API using a limited batch size.
    start = 0
    batch_size = 100 # https://jira.atlassian.com/browse/JRACLOUD-67570
    while True:
        issues = jira.search_issues(jira_query, startAt=start, maxResults=batch_size)
        if len(issues) > 0:
            print("Loaded issues %d-%d" % (start + 1, start + len(issues)), file=sys.stderr)
        else:
            print(":warning: No issues matched the query.") # leave this as a warning
        for jira_issue in issues:
            yield make_icu_issue(jira_issue)
        if len(issues) < batch_size:
            break
        start += batch_size

jira_issue_map = dict() # loaded in main()

def get_single_jira_issue(issue_id, **kwargs):
    """
    Returns a single ICUIssue for the given issue ID.
    This can always be used (in- or out- of query issues), because it
    uses the jira_issue_map as the backing store.
    """
    if issue_id in jira_issue_map:
        # print("Cache hit: issue %s " % (issue_id), file=sys.stderr)
        return jira_issue_map[issue_id]
    jira_url, jira = get_jira_instance(**kwargs)
    jira_issue = jira.issue(issue_id)
    # singleCount = singleCount + 1
    if jira_issue:
        icu_issue = make_icu_issue(jira_issue)
    else:
        icu_issue = None
    jira_issue_map[issue_id] = icu_issue
    print("Loaded single issue %s (%d in cache) " % (issue_id, len(jira_issue_map)), file=sys.stderr)
    return icu_issue

def toplink():
    print("[🔝Top](#table-of-contents)")
    print()

def sectionToFragment(section):
    return re.sub(r' ', '-', section.lower())

# def aname(section):
#     """convert section name to am anchor"""
#     return "<a name=\"%s\"></a>" % sectionToFragment(section)

def print_sectionheader(section):
    """Print a section (###) header, including anchor"""
    print("### %s" % (section))
    #print("### %s%s" % (aname(section), section))

def main():
    args = flag_parser.parse_args()
    print("TIP: Have you pulled the latest master? This script only looks at local commits.", file=sys.stderr)
    if not args.jira_username or not args.jira_password:
        print("WARNING: Jira credentials not supplied. Sensitive tickets will not be found.", file=sys.stderr)
        authenticated = False
    else:
        authenticated = True

    # exclude these, already merged to old maint
    excludeAlreadyMergedToOldMaint = get_cherrypicked_commits(**vars(args))

    commits = list(get_commits(**vars(args)))
    issues = list(get_jira_issues(**vars(args)))

    # commit_issue_ids is all commits in the git query. Excluding cherry exclusions.
    commit_issue_ids = set(commit.issue_id for commit in commits if commit.issue_id is not None and commit.commit.hexsha not in excludeAlreadyMergedToOldMaint)
    # which issues have commits that were excluded
    excluded_commit_issue_ids = set(commit.issue_id for commit in commits if commit.issue_id is not None and commit.commit.hexsha in excludeAlreadyMergedToOldMaint)

    # grouped_commits is all commits and issue_ids in the git query, regardless of issue status
    # but NOT including cherry exclusions
    grouped_commits = [
        (issue_id, [commit for commit in commits if commit.issue_id == issue_id and commit.commit.hexsha not in excludeAlreadyMergedToOldMaint])
        for issue_id in sorted(commit_issue_ids)
    ]
    # add all queried issues to the cache
    for issue in issues:
        jira_issue_map[issue.issue_id] = issue
    # only the issue ids in-query
    jira_issue_ids = set(issue.issue_id for issue in issues)
    # only the closed issue ids in-query
    closed_jira_issue_ids = set(issue.issue_id for issue in issues if issue.is_closed)

    # keep track of issues that we already said have no commit.
    no_commit_ids = set()

    # constants for the section names.
    CLOSED_NO_COMMIT = "Closed Issues with No Commit"
    CLOSED_ILLEGAL_RESOLUTION = "Closed Issues with Illegal Resolution or Commit"
    COMMIT_NO_JIRA = "Commits without Jira Issue Tag"
    COMMIT_OPEN_JIRA = "Commits with Open Jira Issue"
    COMMIT_JIRA_NOT_IN_QUERY = "Commits with Jira Issue Not Found"
    ISSUE_UNDER_REVIEW = "Issue is under Review"

    total_problems = 0
    if not args.nocopyright:
        print("<!--")
        print("Copyright (C) 2021 and later: Unicode, Inc. and others.")
        print("License & terms of use: http://www.unicode.org/copyright.html")
        print("-->")

    print("Commit Report")
    print("=============")
    print()
    print("Environment:")
    print("- Now: %s" % datetime.datetime.now().isoformat())
    print("- Latest Commit: %s/commit/%s" % (args.github_url, commits[0].commit.hexsha))
    print("- Jira Query: `%s`" % args.jira_query)
    print("- Rev Range: `%s`" % args.rev_range)
    print("- Authenticated: %s" % ("`Yes`" if authenticated else "`No` (sensitive tickets not shown)"))
    print()
    print("## Table Of Contents")
    for section in [CLOSED_NO_COMMIT, CLOSED_ILLEGAL_RESOLUTION, COMMIT_NO_JIRA, COMMIT_JIRA_NOT_IN_QUERY, COMMIT_OPEN_JIRA, ISSUE_UNDER_REVIEW]:
        print("- [%s](#%s)" % (section, sectionToFragment(section)))
    print()
    print("## Problem Categories")
    print_sectionheader(CLOSED_NO_COMMIT)
    toplink()
    print("Tip: Tickets with type 'Task' or 'User Guide' or resolution 'Fixed by Other Ticket' are ignored.")
    print()
    found = False
    for issue in issues:
        if not issue.is_closed:
            continue
        if issue.issue_id in commit_issue_ids:
            continue
        if issue.commit_wanted == CommitWanted["OPTIONAL"] or issue.commit_wanted == CommitWanted["FORBIDDEN"]:
            continue
        found = True
        total_problems += 1
        no_commit_ids.add(issue.issue_id)
        pretty_print_issue(issue, type=CLOSED_NO_COMMIT, **vars(args))
        if issue.issue_id in excluded_commit_issue_ids:
            print("\t - **Note: Has cherry-picked commits. Fix Version may be wrong.**")
        print()
    if not found:
        print("*Success: No problems in this category!*")

    print_sectionheader(CLOSED_ILLEGAL_RESOLUTION)
    toplink()
    print("Tip: Fixed tickets should have resolution 'Fixed by Other Ticket' or 'Fixed'.")
    print("Duplicate tickets should have their fixVersion tag removed.")
    print("Tickets with resolution 'Fixed by Other Ticket' are not allowed to have commits.")
    print()
    found = False
    for issue in issues:
        if not issue.is_closed:
            continue
        if issue.commit_wanted == CommitWanted["OPTIONAL"]:
            continue
        if issue.issue_id in commit_issue_ids and issue.commit_wanted == CommitWanted["REQUIRED"]:
            continue
        if issue.issue_id not in commit_issue_ids and issue.commit_wanted == CommitWanted["FORBIDDEN"]:
            continue
        if issue.issue_id in no_commit_ids:
            continue # we already complained about it above. don't double count.
        found = True
        total_problems += 1
        pretty_print_issue(issue, type=CLOSED_ILLEGAL_RESOLUTION, **vars(args))
        if issue.issue_id not in commit_issue_ids and issue.commit_wanted == CommitWanted["REQUIRED"]:
            print("\t- No commits, and they are REQUIRED.")
        if issue.issue_id in commit_issue_ids and issue.commit_wanted == CommitWanted["FORBIDDEN"]:
            print("\t- Has commits, and they are FORBIDDEN.")
        print()
    if not found:
        print("*Success: No problems in this category!*")

    # TODO: This section should usually be empty due to the PR checker.
    # Pre-calculate the count and omit it.
    print()
    print_sectionheader(COMMIT_NO_JIRA)
    toplink()
    print("Tip: If you see your name here, make sure to label your commits correctly in the future.")
    print()
    found = False
    for commit in commits:
        if commit.issue_id is not None:
            continue
        found = True
        total_problems += 1
        pretty_print_commit(commit, type=COMMIT_NO_JIRA, **vars(args))
        print()
    if not found:
        print("*Success: No problems in this category!*")

    print()
    print_sectionheader(COMMIT_JIRA_NOT_IN_QUERY)
    toplink()
    print("Tip: Check that these tickets have the correct fixVersion tag.")
    print()
    found = False
    for issue_id, commits in grouped_commits:
        if issue_id in jira_issue_ids:
            continue
        found = True
        total_problems += 1
        print("#### Issue %s" % issue_id)
        print()
        print("_issue was not found in `%s`_" % args.jira_query) # TODO: link to query?
        jira_issue = get_single_jira_issue(issue_id, **vars(args))
        if jira_issue:
            pretty_print_issue(jira_issue, **vars(args))
        else:
            print("*Jira issue does not seem to exist*")
        print()
        print("##### Commits with Issue %s" % issue_id)
        print()
        for commit in commits:
            if(commit.commit.hexsha in excludeAlreadyMergedToOldMaint):
                print("@@@ ALREADY MERGED")
            pretty_print_commit(commit, **vars(args))
            print()
    if not found:
        print("*Success: No problems in this category!*")

    print()

    # list of issues that are in review
    issues_in_review = set()

    print_sectionheader(COMMIT_OPEN_JIRA)
    toplink()
    print("Tip: Consider closing the ticket if it is fixed.")
    print()
    found = False
    componentToTicket = {}
    def addToComponent(component, issue_id):
        if component not in componentToTicket:
            componentToTicket[component] = set()
        componentToTicket[component].add(issue_id)
    # first, scan ahead for the components
    for issue_id, commits in grouped_commits:
        if issue_id in closed_jira_issue_ids:
            continue
        jira_issue = get_single_jira_issue(issue_id, **vars(args))
        if jira_issue and jira_issue.is_closed:
            # JIRA ticket was not in query, but was actually closed.
            continue
        if jira_issue_under_review(jira_issue):
            print("skipping for now- %s is under review" % issue_id, file=sys.stderr)
            issues_in_review.add(issue_id)
            continue
        # OK. Now, split it out by component
        if jira_issue.issue.fields.components and len(jira_issue.issue.fields.components) > 0:
            for component in jira_issue.issue.fields.components:
                addToComponent(component.name, issue_id)
        else:
            addToComponent("(no component)", issue_id)

    print("#### Open Issues by Component")
    print()
    for component in sorted(componentToTicket.keys()):
        print(" - **%s**: %s" % (component,  ' '.join("[%s](#issue-%s)" % (issue_id, sectionToFragment(issue_id)) for issue_id in componentToTicket[component])))

    print()
    print()

    # now, actually show the ticket list.
    for issue_id, commits in grouped_commits:
        if issue_id in closed_jira_issue_ids:
            continue
        jira_issue = get_single_jira_issue(issue_id, **vars(args))
        if jira_issue and jira_issue.is_closed:
            # JIRA ticket was not in query, but was actually closed.
            continue
        if jira_issue_under_review(jira_issue):
            # We already added it to the review list above.
            continue
        print("#### Issue %s" % issue_id)
        print()
        print("_Jira issue is open_")
        if jira_issue:
            pretty_print_issue(jira_issue, **vars(args))
        else:
            print("*Jira issue does not seem to exist*")
        print()
        print("##### Commits with Issue %s" % issue_id)
        print()
        found = True
        total_problems += 1
        for commit in commits:
            # print("@@@@ %s = %s / %s" % (issue_id, commit, commit.commit.summary), file=sys.stderr)
            pretty_print_commit(commit, **vars(args))
            print()
    if not found:
        print("*Success: No problems in this category!*")

    print_sectionheader(ISSUE_UNDER_REVIEW)
    print()
    toplink()
    print("These issues are otherwise accounted for above, but are in review.")
    for issue_id in sorted(issues_in_review):
        jira_issue = get_single_jira_issue(issue_id, **vars(args))
        pretty_print_issue(jira_issue, type=ISSUE_UNDER_REVIEW, **vars(args))

    print()
    print("## Total Problems: %s" % total_problems)
    print("## Issues under review: %s" % len(issues_in_review)) # not counted as a problem.

if __name__ == "__main__":
    main()