import dataset
import logging
from datetime import datetime
from devplacepy.config import DATABASE_URL

logger = logging.getLogger(__name__)

db = dataset.connect(
    DATABASE_URL,
    engine_kwargs={
        "connect_args": {
            "timeout": 30,
            "check_same_thread": False,
        },
    },
    on_connect_statements=[
        "PRAGMA journal_mode=WAL",
        "PRAGMA synchronous=NORMAL",
        "PRAGMA busy_timeout=30000",
        "PRAGMA cache_size=-8000",
        "PRAGMA temp_store=MEMORY",
        "PRAGMA mmap_size=268435456",
    ],
)


def _index(db, table, name, columns):
    try:
        if table in db.tables:
            cols = ", ".join(columns)
            db.query(f"CREATE INDEX IF NOT EXISTS {name} ON {table} ({cols})")
    except Exception as e:
        logger.warning(f"Could not create index {name} on {table}: {e}")


def init_db():
    tables = db.tables
    _index(db, "users", "idx_users_username", ["username"])
    _index(db, "users", "idx_users_email", ["email"])
    _index(db, "posts", "idx_posts_user_uid", ["user_uid"])
    _index(db, "posts", "idx_posts_created_at", ["created_at"])
    _index(db, "posts", "idx_posts_topic", ["topic"])
    _index(db, "comments", "idx_comments_post_uid", ["post_uid"])
    _index(db, "comments", "idx_comments_target", ["target_type", "target_uid"])
    _index(db, "comments", "idx_comments_user_uid", ["user_uid"])
    _index(db, "votes", "idx_votes_target", ["target_uid", "target_type"])
    _index(db, "messages", "idx_messages_sender", ["sender_uid"])
    _index(db, "messages", "idx_messages_receiver", ["receiver_uid"])
    _index(db, "notifications", "idx_notifications_user", ["user_uid"])
    _index(db, "notifications", "idx_notifications_user_read", ["user_uid", "read"])
    _index(db, "sessions", "idx_sessions_token", ["session_token"])
    _index(db, "projects", "idx_projects_user", ["user_uid"])
    _index(db, "badges", "idx_badges_user", ["user_uid"])
    _index(db, "follows", "idx_follows_follower", ["follower_uid"])
    _index(db, "follows", "idx_follows_following", ["following_uid"])
    _index(db, "password_resets", "idx_password_resets_token", ["token"])

    if "daily_topics" in tables:
        existing = db["daily_topics"].find_one()
        if not existing:
            db["daily_topics"].insert({
                "uid": "default",
                "title": "Anthropic details how it improved Claude's safety...",
                "summary": "New techniques in AI safety research show promising results for alignment of large language models with human values.",
                "updated_at": datetime.utcnow().isoformat(),
            })

    if "site_settings" in tables:
        defaults = {"site_name": "DevPlace", "site_description": "The Developer Social Network", "site_tagline": "Track industry shifts. Discover bold releases. Share what you are building in an open, uncensored environment."}
        for key, value in defaults.items():
            existing = db["site_settings"].find_one(key=key)
            if not existing:
                db["site_settings"].insert({"uid": f"default_{key}", "key": key, "value": value})

    _index(db, "news", "idx_news_external_id", ["external_id"])
    _index(db, "news", "idx_news_synced_at", ["synced_at"])
    _index(db, "news_images", "idx_news_images_news_uid", ["news_uid"])
    _index(db, "news_sync", "idx_news_sync_external_id", ["external_id"])

    if "site_settings" in tables:
        news_defaults = {
            "news_grade_threshold": "7",
            "news_api_url": "https://news.app.molodetz.nl/api",
            "news_ai_url": "https://openai.app.molodetz.nl/v1/chat/completions",
            "news_ai_model": "molodetz",
        }
        for key, value in news_defaults.items():
            existing = db["site_settings"].find_one(key=key)
            if not existing:
                db["site_settings"].insert({"uid": f"default_{key}", "key": key, "value": value})

    logger.info("Database initialized")


def get_table(name):
    return db[name]


def get_users_by_uids(uids):
    if not uids:
        return {}
    seen = set()
    unique = [u for u in uids if u not in seen and not seen.add(u)]
    return {u["uid"]: u for u in db["users"].find(db["users"].table.columns.uid.in_(unique))}


def get_comment_counts_by_post_uids(post_uids):
    if not post_uids or "comments" not in db.tables:
        return {}
    placeholders = ",".join(f"'{u}'" for u in post_uids)
    rows = db.query(f"SELECT post_uid, COUNT(*) as c FROM comments WHERE post_uid IN ({placeholders}) GROUP BY post_uid")
    return {r["post_uid"]: r["c"] for r in rows}


def get_vote_counts(target_uids):
    if not target_uids or "votes" not in db.tables:
        return {}, {}
    placeholders = ",".join(f"'{u}'" for u in target_uids)
    rows = db.query(f"SELECT target_uid, value, COUNT(*) as c FROM votes WHERE target_uid IN ({placeholders}) GROUP BY target_uid, value")
    ups = {}
    downs = {}
    for r in rows:
        if r["value"] == 1:
            ups[r["target_uid"]] = r["c"]
        else:
            downs[r["target_uid"]] = r["c"]
    return ups, downs


def load_comments(target_type, target_uid):
    if "comments" not in db.tables:
        return []
    comments_table = db["comments"]
    raw = list(comments_table.find(target_type=target_type, target_uid=target_uid, order_by=["created_at"]))
    if not raw and target_type == "post":
        raw = list(comments_table.find(post_uid=target_uid, order_by=["created_at"]))
    if not raw:
        return []
    uids = [c["user_uid"] for c in raw]
    cids = [c["uid"] for c in raw]
    users = get_users_by_uids(uids)
    ups, downs = get_vote_counts(cids)
    from devplacepy.utils import time_ago
    cmap = {}
    for c in raw:
        cmap[c["uid"]] = {
            "comment": c,
            "author": users.get(c["user_uid"]),
            "time_ago": time_ago(c["created_at"]),
            "votes": {"up": ups.get(c["uid"], 0), "down": downs.get(c["uid"], 0)},
            "children": [],
        }
    top = []
    for item in cmap.values():
        parent = item["comment"].get("parent_uid")
        if parent and parent in cmap:
            cmap[parent]["children"].append(item)
        else:
            top.append(item)
    return top


def get_daily_topic():
    topics = db["daily_topics"]
    topic = topics.find_one()
    if topic:
        return topic
    return {"title": "Anthropic details how it improved Claude's safety...", "summary": "New techniques in AI safety research show promising results."}