"""A private family register, independent from login accounts and camera roles."""
import datetime as dt
import json
import secrets


class Family:
    def __init__(self, app):
        self.a = app

    def initialize(self):
        with self.a.LOCK:
            self.a.DB.executescript('''
            CREATE TABLE IF NOT EXISTS people (id TEXT PRIMARY KEY, body TEXT NOT NULL);
            CREATE TABLE IF NOT EXISTS family_links (id TEXT PRIMARY KEY, body TEXT NOT NULL);
            ''')
            self.a.DB.commit()

    def authorize(self, user, edit=False):
        if user['role'] != 'admin' and user.get('familyAccess', 'none') not in (('edit',) if edit else ('read', 'edit')):
            raise self.a.Problem('没有家谱' + ('编辑' if edit else '查看') + '权限', 403)

    def snapshot(self, user):
        self.authorize(user)
        with self.a.LOCK:
            return {'revision': self.a.setting('familyRevision', 0), 'people': self.a.objects('people'),
                    'links': self.a.objects('family_links'),
                    'canEdit': user['role'] == 'admin' or user.get('familyAccess') == 'edit',
                    'selfId': user.get('personId', '')}

    def save(self, kind, data, user):
        self.authorize(user, True)
        a = self.a
        with a.LOCK:
            revision = a.setting('familyRevision', 0)
            if type(data.get('revision')) is not int or data['revision'] != revision:
                raise a.Problem('家谱已被更新，请重新载入后再编辑', 409)
            table = 'people' if kind == 'person' else 'family_links'
            old = a.get_object(table, data.get('id'))
            if data.get('id') and not old:
                raise a.Problem('家谱记录不存在', 404)
            item = self.person(data, old) if kind == 'person' else self.link(data, old)
            item.update(updatedAt=dt.datetime.now(dt.timezone.utc).isoformat(), updatedBy=user['username'])
            # Revision and record are committed together, so concurrent forms cannot overwrite silently.
            a.DB.execute('INSERT OR REPLACE INTO ' + table + ' VALUES (?,?)', (item['id'], json.dumps(item)))
            a.DB.execute('INSERT OR REPLACE INTO settings VALUES (?,?)', ('familyRevision', json.dumps(revision + 1)))
            a.DB.commit()
            a.audit('更新家谱人物' if kind == 'person' else '更新家谱关系', user['username'])
            return {'item': item, 'revision': revision + 1}

    def person(self, data, old):
        a = self.a
        item = {'id': old['id'] if old else secrets.token_hex(8)}
        for key, maximum in [('name', 80), ('alias', 120), ('birthDate', 10), ('deathDate', 10),
                             ('birthplace', 160), ('biography', 2000), ('note', 500)]:
            value = data.get(key, '')
            if key in ('biography', 'note'):
                if not isinstance(value, str) or len(value) > maximum or any(ord(c) < 32 and c not in '\r\n\t' for c in value):
                    raise a.Problem('生平或备注格式不正确')
                item[key] = value.strip()
            else:
                item[key] = a.clean_text(value, maximum, key == 'name')
        for key in ('birthDate', 'deathDate'):
            if item[key]:
                try:
                    if dt.date.fromisoformat(item[key]).isoformat() != item[key]:
                        raise ValueError()
                except ValueError:
                    raise a.Problem('日期请使用公历 YYYY-MM-DD；不确定可留空，在备注记录')
        if item['birthDate'] and item['deathDate'] and item['birthDate'] > item['deathDate']:
            raise a.Problem('逝世日期不能早于出生日期')
        item['gender'] = data.get('gender', 'unknown')
        item['lifeStatus'] = data.get('lifeStatus', 'unknown')
        if item['gender'] not in ('male', 'female', 'unknown') or item['lifeStatus'] not in ('alive', 'deceased', 'unknown'):
            raise a.Problem('人物属性不正确')
        if item['deathDate'] and item['lifeStatus'] != 'deceased':
            raise a.Problem('填写逝世日期时，请选择已故')
        item['archived'] = data.get('archived', False)
        if not isinstance(item['archived'], bool):
            raise a.Problem('归档状态不正确')
        return item

    def link(self, data, old):
        a = self.a
        left, right = data.get('fromId'), data.get('toId')
        if not isinstance(left, str) or not isinstance(right, str) or not a.get_object('people', left) or not a.get_object('people', right):
            raise a.Problem('请先录入关系双方的人物')
        if left == right:
            raise a.Problem('不能把人物与自己建立亲属关系')
        kind = data.get('kind')
        if kind not in ('parent', 'spouse'):
            raise a.Problem('关系类型不正确')
        lineage = data.get('lineage', 'unspecified')
        if lineage not in ('biological', 'adoptive', 'step', 'unspecified'):
            raise a.Problem('亲子关系属性不正确')
        active = data.get('active', True)
        if not isinstance(active, bool):
            raise a.Problem('关系状态不正确')
        item = dict(id=old['id'] if old else secrets.token_hex(8), fromId=left, toId=right, kind=kind,
                    lineage=lineage if kind == 'parent' else 'unspecified', active=active,
                    note=a.clean_text(data.get('note', ''), 300))
        links = [e for e in a.objects('family_links') if e.get('active') and e['id'] != item['id']]
        if active:
            for e in links:
                same = (e['fromId'], e['toId']) == (left, right)
                if kind == 'spouse':
                    same = {e['fromId'], e['toId']} == {left, right}
                if e['kind'] == kind and same:
                    raise a.Problem('这条关系已经存在', 409)
            graph = {}
            for e in links + [item]:
                if e['kind'] == 'parent':
                    graph.setdefault(e['fromId'], []).append(e['toId'])
            # Iterative walk supports deep ancestry without Python recursion limits.
            def reaches(start, target):
                pending, seen = [start], set()
                while pending:
                    p = pending.pop()
                    if p in seen:
                        continue
                    seen.add(p)
                    for child in graph.get(p, []):
                        if child == target:
                            return True
                        pending.append(child)
                return False
            if kind == 'parent' and reaches(right, left):
                raise a.Problem('这条关系会形成祖先与后代循环，请检查方向')
            for e in links + [item]:
                if e['kind'] == 'spouse' and (reaches(e['fromId'], e['toId']) or reaches(e['toId'], e['fromId'])):
                    raise a.Problem('配偶不能同时是直系祖先或后代，请检查已有关系')
        return item