import yaml
import caldav
import sys

if len(sys.argv) > 1:
    import os
    os.chdir(sys.argv[1])

with open('auth.yaml') as f:
    auth = yaml.full_load(f)
try:
    with open('data.yaml') as f:
        known = yaml.full_load(f)
except:
    known = {}

logins = {}
for login, content in auth['logins'].items():
    logins[login] = caldav.DAVClient(url=content['url'], username=content['user'], password=content['password'])

cals = []
for cal in auth['cals']:
    cals.append(caldav.Calendar(client = logins[cal['login']], url = cal['url']))

changed = {}
deleted = {}

def cal_contains_uid(cal, uid):
    try:
        event = cal.event_by_uid(uid)
        return True
    except caldav.lib.error.NotFoundError:
        return False

for cal in cals:
    print("Checking %s" % (cal.canonical_url,))
    for event in cal.events():
        uid = event.vobject_instance.vevent.uid.value
        data = event.data
        entry = (cal.canonical_url, event)

        if uid not in known:
            print("Found new event with summary %s" % (event.vobject_instance.vevent.summary.value,))
            if uid not in changed:
                changed[uid] = [entry]
            else:
                changed[uid].append(entry)
        else:
            if data != known[uid]:
                print("Found changed event with summary %s" % (event.vobject_instance.vevent.summary.value,))
                if uid not in changed:
                    changed[uid] = [entry]
                else:
                    changed[uid].append(entry)

print("Checking for deletions")
for uid, data in known.items():
    for cal in cals:
        if not cal_contains_uid(cal, uid):
            print("Item with uid %s got deleted in %s" % (uid, cal.canonical_url))
            if uid not in deleted:
                deleted[uid] = [cal.canonical_url]
            else:
                deleted[uid].append(cal.canonical_url)

for uid, arr in changed.items():
    if uid in deleted:
        print("Changed/new entry with UID (%s), summary \"%s\" was also deleted, recreating it." % (uid, arr[0][1].vobject_instance.vevent.uid.value), file=sys.stderr)
        print("Deletions in:", file=sys.stderr)
        for cal in deleted[uid]:
            print("  - %s" % (cal,), file=sys.stderr)
        print("Changes in:", file=sys.stderr)
        for entry in arr:
            print("  - %s" % (entry[0],), file=sys.stderr)
        print("", file=sys.stderr)
        del deleted[uid]
        

    if len(set([entry[1].data for entry in arr])) != 1:
        print("Multiple changed/new entries with the same UID (%s) detected:" % (uid,), file=sys.stderr)
        for ev in arr:
            print("  %s: %s" % (ev[0], ev[1].vobject_instance.vevent.summary.value), file = sys.stderr)
        continue
    
    entry = arr[0]
    changed_cals = [ entry[0] for entry in arr ]
    for cal in cals:
        if cal.canonical_url not in changed_cals:
            try:
                old = cal.event_by_uid(uid)
                print("Overwriting event from %s with data %s (source: %s)" % (cal.canonical_url, repr(old.data), changed_cals))
                new = False
            except:
                new = True
            cal.save_event(entry[1].data)
            if new:
                print("Creating new event in %s with summary %s" % (cal.canonical_url, cal.event_by_uid(uid).vobject_instance.vevent.summary.value))
    known[uid] = entry[1].data

for uid in deleted:
    for cal in cals:
        if cal_contains_uid(cal, uid):
            evt = cal.event_by_uid(uid)
            print("Deleting event from %s with data %s (source: %s)" % (cal.canonical_url, repr(evt.data), deleted[uid]))
            cal.event_by_uid(uid).delete()
    del known[uid]

print("Done.")
print()

with open("data.yaml", "w") as f:
    yaml.dump(known, f)