import { z } from "zod";

import { getDb } from "@tline/db";

export const runtime = "nodejs";

const querySchema = z
  .object({
    start: z.string().datetime().optional(),
    end: z.string().datetime().optional(),
    granularity: z.enum(["year", "month", "day"]).default("day"),
    mediaType: z.enum(["image", "video"]).optional(),
    includeFailed: z.enum(["0", "1"]).default("0").transform((v) => v === "1"),
    limit: z.coerce.number().int().positive().max(500).default(200),
  })
  .strict();

type Granularity = z.infer<typeof querySchema>["granularity"];

function sqlGroupExpr(granularity: Granularity, alias: string) {
  const col = `${alias}.capture_ts_utc`;
  if (granularity === "year") return `date_trunc('year', ${col})`;
  if (granularity === "month") return `date_trunc('month', ${col})`;
  return `date_trunc('day', ${col})`;
}

export async function GET(request: Request): Promise<Response> {
  const url = new URL(request.url);

  const parsed = querySchema.safeParse({
    start: url.searchParams.get("start") ?? undefined,
    end: url.searchParams.get("end") ?? undefined,
    granularity: url.searchParams.get("granularity") ?? undefined,
    mediaType: url.searchParams.get("mediaType") ?? undefined,
    includeFailed: url.searchParams.get("includeFailed") ?? undefined,
    limit: url.searchParams.get("limit") ?? undefined,
  });

  if (!parsed.success) {
    return Response.json(
      { error: "invalid_query", issues: parsed.error.issues },
      { status: 400 },
    );
  }

  const query = parsed.data;

  const start = query.start ? new Date(query.start) : null;
  const end = query.end ? new Date(query.end) : null;

  const db = getDb();

  // Note: capture_ts_utc can be null (unprocessed). Those rows are excluded.
  const groupExprFiltered = sqlGroupExpr(query.granularity, "filtered");
  const groupExprF = sqlGroupExpr(query.granularity, "f");

  const rows = await db<
    {
      bucket: string;
      group_ts: string;
      count_total: number;
      count_ready: number;
      sample_asset_id: string | null;
      sample_thumb_small_key: string | null;
      sample_thumb_med_key: string | null;
      sample_poster_key: string | null;
      sample_active_key: string | null;
      sample_status: string | null;
      sample_media_type: "image" | "video" | null;
    }[]
  >`
    with filtered as (
      select
        id,
        bucket,
        media_type,
        status,
        capture_ts_utc,
        active_key,
        thumb_small_key,
        thumb_med_key,
        poster_key
      from assets
      where capture_ts_utc is not null
        and (${start}::timestamptz is null or capture_ts_utc >= ${start}::timestamptz)
        and (${end}::timestamptz is null or capture_ts_utc < ${end}::timestamptz)
        and (${query.mediaType ?? null}::media_type is null or media_type = ${query.mediaType ?? null}::media_type)
        and (
          ${query.includeFailed}::boolean = true
          or status <> 'failed'
        )
    ),
    grouped as (
      select
        bucket,
        ${db.unsafe(groupExprFiltered)} as group_ts,
        count(*)::int as count_total,
        count(*) filter (where status = 'ready')::int as count_ready
      from filtered
      group by bucket, ${db.unsafe(groupExprFiltered)}
      order by group_ts desc
      limit ${query.limit}
    )
    select
      g.bucket,
      to_char(g.group_ts AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS"Z"') as group_ts,
      g.count_total,
      g.count_ready,
      s.id as sample_asset_id,
      s.thumb_small_key as sample_thumb_small_key,
      s.thumb_med_key as sample_thumb_med_key,
      s.poster_key as sample_poster_key,
      s.active_key as sample_active_key,
      s.status as sample_status,
      s.media_type as sample_media_type
    from grouped g
    left join lateral (
      select *
      from filtered f
      where f.bucket = g.bucket
        and ${db.unsafe(groupExprF)} = g.group_ts
        and f.status = 'ready'
      order by f.capture_ts_utc asc
      limit 1
    ) s on true
    order by g.group_ts desc
  `;

  return Response.json({
    granularity: query.granularity,
    start: start ? start.toISOString() : null,
    end: end ? end.toISOString() : null,
    mediaType: query.mediaType ?? null,
    includeFailed: query.includeFailed,
    nodes: rows,
  });
}