from datetime import datetime

import asyncpg

from utils.read.models import CaptureGap, CaptureStatus

_STATUS = """
SELECT started_at, seen_at, seen_at >= now() - interval '150 seconds' AS live
FROM capture_uptime WHERE account_id = $1
ORDER BY started_at DESC LIMIT 1
"""

_GAPS = """
SELECT seen_at AS start, next_start AS "end"
FROM (
    SELECT seen_at,
           lead(started_at) OVER (ORDER BY started_at) AS next_start
    FROM capture_uptime WHERE account_id = $1
) stretches
WHERE next_start - seen_at > interval '30 minutes'
  AND ($2::timestamptz IS NULL OR next_start >= $2)
  AND ($3::timestamptz IS NULL OR seen_at <= $3)
ORDER BY seen_at
"""


async def capture_status(pool: asyncpg.Pool, account_id: int) -> CaptureStatus:
    row = await pool.fetchrow(_STATUS, account_id)
    if row is None:
        return CaptureStatus(live=False, since=None, last_seen=None)
    return CaptureStatus(
        live=row["live"], since=row["started_at"], last_seen=row["seen_at"]
    )


async def capture_gaps(
    pool: asyncpg.Pool,
    account_id: int,
    *,
    date_from: datetime | None = None,
    date_to: datetime | None = None,
) -> list[CaptureGap]:
    rows = await pool.fetch(_GAPS, account_id, date_from, date_to)
    return [CaptureGap(**dict(row)) for row in rows]