-- Durable timing log for crawler operations + a duration column for page
-- analysis. The dashboard's job history shows *what* ran; this records *how
-- long it took* so operators can see per-operation durations and averages
-- broken down by type/granularity (manga list walk, manga detail, cover,
-- whole chapter — per-page crawl timing is derived from the chapter row's
-- `items` count rather than stored per image).
--
-- This table is durable on purpose: it outlives the `crawler_jobs` done-job
-- reaper so averages stay meaningful, and it captures the INLINE operations
-- (list walk, manga detail, cover) that are not queue jobs at all. Volume is
-- low (one row per manga / chapter / pass, not per image), so a generous
-- retention reaper is hygiene rather than a necessity.
CREATE TABLE crawl_metrics (
    id          uuid PRIMARY KEY DEFAULT gen_random_uuid(),
    -- Operation granularity. analyze_page is intentionally absent — analysis
    -- duration lives on page_analysis.duration_ms (one row per page already).
    op          text NOT NULL
                    CHECK (op IN ('manga_list', 'manga_detail', 'manga_cover', 'chapter')),
    -- Best-effort target context for labeling/drill. SET NULL so deleting a
    -- manga/chapter doesn't erase its historical timings.
    manga_id    uuid REFERENCES mangas(id) ON DELETE SET NULL,
    chapter_id  uuid REFERENCES chapters(id) ON DELETE SET NULL,
    outcome     text NOT NULL CHECK (outcome IN ('ok', 'failed')),
    duration_ms bigint NOT NULL,
    -- Unit count for the op: chapter = pages stored; manga_list = mangas
    -- discovered. Drives the derived "per page" average. NULL when N/A.
    items       integer,
    error       text,
    finished_at timestamptz NOT NULL DEFAULT now()
);

-- Per-type averages + the recent-ops log both filter by op and order by time.
CREATE INDEX crawl_metrics_op_time_idx ON crawl_metrics (op, finished_at DESC);
-- The window filter (last 24h / 7d / 30d) and the retention reaper scan by time.
CREATE INDEX crawl_metrics_time_idx ON crawl_metrics (finished_at);

-- Wall-clock the analysis worker spent on a page (vision dispatch). NULL for
-- pre-existing rows and any page analyzed before this migration.
ALTER TABLE page_analysis ADD COLUMN duration_ms bigint;