import json
import secrets
from datetime import datetime

import asyncpg

from utils.read.models import DeliveryView, WebhookView

STATUS_PENDING = "pending"
STATUS_SENDING = "sending"
STATUS_DELIVERED = "delivered"
STATUS_FAILED = "failed"
DELIVERY_LOG = 20

_DELIVERY_COLS = (
    "id, webhook_id, alert_id, event, status, attempts, next_attempt_at, "
    "response_code, last_error, created_at, finished_at"
)

_HOOKS = f"""
SELECT w.id, w.account_id, w.url, w.secret, w.enabled, w.watch_ids,
       w.created_at, w.updated_at, to_jsonb(d) AS last_delivery
FROM webhooks w
LEFT JOIN LATERAL (
    SELECT {_DELIVERY_COLS} FROM webhook_deliveries
    WHERE webhook_id = w.id ORDER BY id DESC LIMIT 1
) d ON true
"""  # noqa: S608

_CLAIM = """
UPDATE webhook_deliveries d SET status = 'sending', attempts = d.attempts + 1
FROM webhooks w
WHERE w.id = d.webhook_id AND d.id IN (
    SELECT id FROM webhook_deliveries
    WHERE status = 'pending' AND next_attempt_at <= now()
    ORDER BY next_attempt_at LIMIT $1
    FOR UPDATE SKIP LOCKED
)
RETURNING d.id, d.alert_id, d.event, d.attempts, d.body,
          w.id AS webhook_id, w.account_id, w.url, w.secret
"""

_FINISH = """
UPDATE webhook_deliveries SET
    status = $2, response_code = $3, last_error = $4,
    next_attempt_at = coalesce($5, next_attempt_at),
    finished_at = CASE WHEN $2 = 'pending' THEN NULL ELSE now() END
WHERE id = $1
"""


def new_secret() -> str:
    return secrets.token_hex(32)


def _to_webhook(row: asyncpg.Record) -> WebhookView:
    data = dict(row)
    last = data.pop("last_delivery")
    return WebhookView(
        **data, last_delivery=DeliveryView(**json.loads(last)) if last else None
    )


async def list_webhooks(pool: asyncpg.Pool, account_id: int) -> list[WebhookView]:
    rows = await pool.fetch(
        f"{_HOOKS} WHERE w.account_id = $1 ORDER BY w.id", account_id
    )
    return [_to_webhook(row) for row in rows]


async def get_webhook(pool: asyncpg.Pool, webhook_id: int) -> WebhookView | None:
    row = await pool.fetchrow(f"{_HOOKS} WHERE w.id = $1", webhook_id)
    return _to_webhook(row) if row else None


async def create_webhook(
    pool: asyncpg.Pool,
    account_id: int,
    url: str,
    watch_ids: list[int] | None,
    *,
    enabled: bool,
) -> WebhookView | None:
    webhook_id = await pool.fetchval(
        "INSERT INTO webhooks (account_id, url, secret, enabled, watch_ids) "
        "VALUES ($1, $2, $3, $4, $5) RETURNING id",
        account_id,
        url,
        new_secret(),
        enabled,
        watch_ids,
    )
    return await get_webhook(pool, webhook_id)


async def update_webhook(
    pool: asyncpg.Pool,
    webhook_id: int,
    url: str,
    watch_ids: list[int] | None,
    *,
    enabled: bool,
) -> WebhookView | None:
    async with pool.acquire() as conn, conn.transaction():
        found = await conn.fetchval(
            "UPDATE webhooks SET url = $2, enabled = $3, watch_ids = $4, "
            "updated_at = now() WHERE id = $1 RETURNING id",
            webhook_id,
            url,
            enabled,
            watch_ids,
        )
        if found is not None and not enabled:
            await conn.execute(
                "UPDATE webhook_deliveries SET status = 'failed', "
                "last_error = 'endpoint disabled', finished_at = now() "
                "WHERE webhook_id = $1 AND status = 'pending'",
                webhook_id,
            )
    return await get_webhook(pool, webhook_id)


async def rotate_secret(pool: asyncpg.Pool, webhook_id: int) -> WebhookView | None:
    await pool.execute(
        "UPDATE webhooks SET secret = $2, updated_at = now() WHERE id = $1",
        webhook_id,
        new_secret(),
    )
    return await get_webhook(pool, webhook_id)


async def delete_webhook(pool: asyncpg.Pool, webhook_id: int) -> bool:
    result = await pool.execute("DELETE FROM webhooks WHERE id = $1", webhook_id)
    return result.endswith("1")


async def list_deliveries(
    pool: asyncpg.Pool, webhook_id: int, limit: int = DELIVERY_LOG
) -> list[DeliveryView]:
    rows = await pool.fetch(
        f"SELECT {_DELIVERY_COLS} FROM webhook_deliveries "  # noqa: S608
        "WHERE webhook_id = $1 ORDER BY id DESC LIMIT $2",
        webhook_id,
        limit,
    )
    return [DeliveryView(**dict(row)) for row in rows]


async def get_delivery(pool: asyncpg.Pool, delivery_id: int) -> DeliveryView | None:
    row = await pool.fetchrow(
        f"SELECT {_DELIVERY_COLS} FROM webhook_deliveries WHERE id = $1",  # noqa: S608
        delivery_id,
    )
    return DeliveryView(**dict(row)) if row else None


async def start_test(pool: asyncpg.Pool, webhook_id: int, body: str) -> int:
    return await pool.fetchval(
        "INSERT INTO webhook_deliveries (webhook_id, event, status, attempts, body) "
        "VALUES ($1, 'test', 'sending', 1, $2) RETURNING id",
        webhook_id,
        body,
    )


async def release_stuck(pool: asyncpg.Pool) -> None:
    await pool.execute(
        "UPDATE webhook_deliveries SET status = 'pending' WHERE status = 'sending'"
    )


async def claim_due(pool: asyncpg.Pool, limit: int) -> list[asyncpg.Record]:
    return await pool.fetch(_CLAIM, limit)


async def save_body(pool: asyncpg.Pool, delivery_id: int, body: str) -> None:
    await pool.execute(
        "UPDATE webhook_deliveries SET body = $2 WHERE id = $1", delivery_id, body
    )


async def finish(  # noqa: PLR0913
    pool: asyncpg.Pool,
    delivery_id: int,
    status: str,
    response_code: int | None,
    error: str | None,
    next_attempt_at: datetime | None = None,
) -> None:
    await pool.execute(
        _FINISH, delivery_id, status, response_code, error, next_attempt_at
    )


async def next_due(pool: asyncpg.Pool) -> datetime | None:
    return await pool.fetchval(
        "SELECT min(next_attempt_at) FROM webhook_deliveries WHERE status = 'pending'"
    )