#!/usr/bin/env python3
import os
import datetime
import requests
import json
from functools import partial

import sys
sys.path.insert(0, '../..')
from settings import GITHUB_USER, GITHUB_TOKEN

MAINTENANCE_PING_BODY=open("./maintenance_ping_body").read().strip()
UNMAINTAINED_WARNING=open("./unmaintained_warning").read().strip()

def get_github(uri):
    with requests.Session() as s:
        s.headers.update({"Authorization": "token {}".format(GITHUB_TOKEN)})
        r = s.get("https://api.github.com" + uri)

    assert r.status_code == 200, "Couldn't get {uri} . Reponse : {text}".format(uri=uri, text=r.text)
    j = json.loads(r.text)
    return j

def github_date_to_days_ago(date):
    now = datetime.datetime.now()
    date = datetime.datetime.strptime(date, "%Y-%m-%dT%H:%M:%SZ")
    return (now - date).days

def get_issues(repo):
    return get_github("/repos/{repo}/issues".format(repo=repo))

def look_for_active_maintenance_ping(issues):

    for issue in issues:
        if issue["title"].startswith("[Maintenance ping]"):
            if issue["state"] == "open":
                issue["created_days_ago"] = github_date_to_days_ago(issue["created_at"])
                return issue

    return None


def look_for_old_maintenance_ping(issues):

    for issue in issues:
        if issue["title"].startswith("[Maintenance ping]"):
            if issue["state"] == "closed":
                issue["updated_days_ago"] = github_date_to_days_ago(issue["updated_at"])
                return issue

    return None


def get_commit_days_ago(repo, branch):

    ref = get_github("/repos/{repo}/git/refs/heads/{branch}".format(repo=repo, branch=branch))
    if not "object" in ref:
        return 99999

    sha = ref["object"]["sha"]
    github_date = get_github("/repos/{repo}/commits/{sha}".format(repo=repo, sha=sha))["commit"]["author"]["date"]

    return github_date_to_days_ago(github_date)


def create_maintenance_ping(repo):
    api_url = "https://api.github.com/repos/{repo}/issues".format(repo=repo)

    issue = { "title": "[Maintenance ping] Is this app still maintained ?",
              "body": MAINTENANCE_PING_BODY
            }

    with requests.Session() as s:
        s.headers.update({"Authorization": "token {}".format(GITHUB_TOKEN)})
        r = s.post(api_url, json.dumps(issue))

    return "Created maintenance ping %s" % json.loads(r.text)["html_url"]

def add_comment_about_unmaintained_state(repo, issue):

    issue_id = issue["number"]
    comments = get_github("/repos/{repo}/issues/{id}/comments".format(repo=repo, id=issue_id))
    existing_warning = [ c for c in comments if c["user"]["login"] == GITHUB_USER
                                             and c["body"].startswith(UNMAINTAINED_WARNING[:20]) ]
    # Nothing to do if there's already a warning about unmaintenained status...
    if existing_warning:
        return

    # Otherwise, post a comment
    api_url = "https://api.github.com/repos/{repo}/issues/{id}/comments" \
              .format(repo=repo, id=issue_id)
    comment = { "body": UNMAINTAINED_WARNING }
    with requests.Session() as s:
        s.headers.update({"Authorization": "token {}".format(GITHUB_TOKEN)})
        r = s.post(api_url, json.dumps(comment))

    return "Added comment %s" % json.loads(r.text)["html_url"]


def get_status_and_todo(repo):

    # (Get issues of repo)
    issues = get_issues(repo)

    # Is a maintenance ping already opened ?
    active_maintenance_ping = look_for_active_maintenance_ping(issues)

    if active_maintenance_ping:
        # since more than 15 days ?
        if active_maintenance_ping["created_days_ago"] >= 14:
            # yes - > unmaintained !
            # -> post a comment if not already done
            return (False, partial(add_comment_about_unmaintained_state,
                                   issue=active_maintenance_ping))
        else:
            # no - > maintained ! (but status being questionned)
            return (True, None)

    # Commit in master or testing in last 18 months ?
    if get_commit_days_ago(repo, "master")  < 18*30 \
    or get_commit_days_ago(repo, "testing") < 18*30:
        # ok, maintained
        return (True, None)

    # Maintainenance status is now being questionned...
    # Was there a (now closed) maintenance ping in the last 6 months ?
    old_maintenance_ping = look_for_old_maintenance_ping(issues)
    if old_maintenance_ping and old_maintenance_ping["update_days_ago"] < 6*30:
        # Yes - > ok, maintained
        return (True, None)
    else:
        # No - > Gotta create a maintenance ping ! (but still considered maintained)
        return (True, create_maintenance_ping)

def get_apps_to_check():

    #official="https://raw.githubusercontent.com/YunoHost/apps/master/official.json"
    community="https://raw.githubusercontent.com/YunoHost/apps/master/community.json"

    raw_apps = []
    #raw_apps += json.loads(requests.get(official).text).values()
    raw_apps += json.loads(requests.get(community).text).values()

    return [ app["url"].replace("https://github.com/","") \
            for app in raw_apps \
            if app["state"] in ["validated", "working", "inprogress"] ]


def analyze_apps():

    monitored_apps = get_apps_to_check()

    status = {}
    todo = {}

    # For each monitored app :
    for app in monitored_apps:

        print("Checking {} ...".format(app))

        try:
            status[app], todo[app] = get_status_and_todo(app)
        except Exception as e:
            print("Failed to fetch status / todo for %s" % app)
            print(e)
            continue

    return (monitored_apps, status, todo)


def run_todolist(todolist):

    done = []

    for app, todo in todolist.items():
        if todo is None:
            continue
        print("Running todo action for app %s" % app)
        try:
            answer = todo(app)
        except:
            print("Failed to run todo action %s for app %s" % (todo, app))
            continue
        done.append(answer)

    for d in done:
        print(d)


def update_community_list(status, workdir):

    filename = workdir + "/community.json"

    j = json.loads(open(filename).read())

    def findapp(repo):
        for app in j.keys():
            if j[app]["url"].endswith('/'+repo):
                return app

    for apprepo, state in status.items():
        app = findapp(apprepo)
        current_state = j[app].get("maintained", True)
        if state != current_state:
            j[app]["maintained"] = False

    open(filename, "w").write(json.dumps(j,
                              sort_keys=True,
                              indent=4,
                              separators=(',', ': ')))


def create_pull_request(repo, watdo, pr_infos):

    owner, reponame = repo.split('/')
    branch, title, body = pr_infos

    #
    # Phase 1 : Clone and prepare
    #

    cmds = [
        "rm -rf .work",
        "mkdir .work",
        "git clone https://github.com/{repo} .work/{reponame}",
        "cd .work/{reponame} && git remote rm origin",
        "cd .work/{reponame} && git remote add origin https://{login}:{token}@github.com/{login}/{reponame}",
        "cd .work/{reponame} && git checkout -b {branch}"
    ]

    for cmd in cmds:
        print(cmd)
        r = os.system(cmd.format(repo=repo,
                                 reponame=reponame,
                                 login=GITHUB_USER,
                                 token=GITHUB_TOKEN,
                                 branch=branch))
        assert r == 0

    #
    # Phase 2 : apply changes, commit and push
    #

    watdo(workdir=".work/%s" % reponame)

    cmds = [
        "cd .work/{reponame} && git add .",
        "cd .work/{reponame} && git commit -a -m '{title}'",
        "cd .work/{reponame} && git push origin {branch}"
    ]

    for cmd in cmds:
        print(cmd)
        r = os.system(cmd.format(reponame=reponame,
                                 branch=branch,
                                 title=title))
        assert r == 0

    #
    # Phase 3 : create the PR
    #

    api_url = "https://api.github.com/repos/{repo}/pulls".format(repo=repo)

    PR = { "title": title,
            "head": GITHUB_USER+":"+branch,
            "base": "master",
            "maintainer_can_modify": True
    }

    with requests.Session() as s:
        s.headers.update({"Authorization": "token {token}".format(token=GITHUB_TOKEN)})
        r = s.post(api_url, json.dumps(PR))

    if r.status_code != 200:
        print(r.text)
    else:
        json.loads(r.text)["html_url"]


def main():

    monitored, maintained, todolist = analyze_apps()

    run_todolist(todolist)

    create_pull_request("YunoHost/apps",
                        partial(update_community_list, status=maintained),
                        ("update-maintained-state",
                         "Update maintained state",
                         "Automatic update of maintenance state following maintenance pings")
                        )

main()