// Code generated by sqlc. DO NOT EDIT.
// versions:
//   sqlc v1.31.1
// source: genre_mixes.sql

package dbq

import (
	"context"

	"github.com/jackc/pgx/v5/pgtype"
)

const listGenreMixCandidates = `-- name: ListGenreMixCandidates :many

WITH library_genres AS (
    SELECT lower(trim(g.g))           AS genre_key,
           min(trim(g.g))::text       AS label,
           COUNT(DISTINCT t.id)        AS track_count,
           array_agg(DISTINCT t.artist_id)::uuid[] AS artist_ids
      FROM tracks t
      CROSS JOIN LATERAL regexp_split_to_table(coalesce(t.genre, ''), '[;,]') AS g(g)
     WHERE t.missing_since IS NULL
       AND trim(g.g) <> ''
     GROUP BY lower(trim(g.g))
    HAVING COUNT(DISTINCT t.id) >= 25
       AND COUNT(DISTINCT t.artist_id) >= 3
),
taste AS (
    SELECT lower(trim(tpt.tag)) AS genre_key, SUM(tpt.weight) AS weight
      FROM taste_profile_tags tpt
     WHERE tpt.user_id = $1
     GROUP BY lower(trim(tpt.tag))
    HAVING SUM(tpt.weight) > 0
),
listened AS (
    SELECT t.id
      FROM play_events pe
      JOIN tracks t ON t.id = pe.track_id
     WHERE pe.user_id = $1 AND pe.was_skipped = false
    UNION ALL
    SELECT gl.track_id
      FROM general_likes gl
     WHERE gl.user_id = $1
),
history AS (
    SELECT lower(trim(g.g)) AS genre_key, COUNT(*) AS plays
      FROM listened l
      JOIN tracks t ON t.id = l.id
      CROSS JOIN LATERAL regexp_split_to_table(coalesce(t.genre, ''), '[;,]') AS g(g)
     WHERE trim(g.g) <> ''
     GROUP BY lower(trim(g.g))
)
SELECT lg.genre_key::text AS genre_key,
       lg.label           AS label,
       (CASE WHEN ta.genre_key IS NOT NULL THEN 1
             WHEN h.genre_key  IS NOT NULL THEN 2
             ELSE 3 END)::int AS tier,
       (CASE WHEN ta.genre_key IS NOT NULL THEN ta.weight
             WHEN h.genre_key  IS NOT NULL THEN h.plays::float8
             ELSE lg.track_count::float8 END)::float8 AS score,
       lg.artist_ids
  FROM library_genres lg
  LEFT JOIN taste   ta ON ta.genre_key = lg.genre_key
  LEFT JOIN history h  ON h.genre_key  = lg.genre_key
 ORDER BY tier, score DESC, lg.genre_key
 LIMIT 60
`

type ListGenreMixCandidatesRow struct {
	GenreKey  string
	Label     string
	Tier      int32
	Score     float64
	ArtistIds []pgtype.UUID
}

// Candidate queries for the genre mixes: one daily system playlist per genre
// the user listens to. Genres live inline on tracks.genre as a delimited
// string and are split on [;,] the same way the Discover and radio tag arms
// split them. Matching is case-insensitive, so the ID3 "Post-Punk" and the
// folksonomy "post-punk" in the taste profile count as one genre.
// Library genres big enough to carry a mix (>= 25 playable tracks across
// >= 3 artists), each tagged with how close it is to the user's listening:
//
//	tier 1: a positive taste-profile genre, scored by its taste weight
//	tier 2: a genre of tracks the user has played through or liked, scored
//	        by how many — catches a profile that has not been built yet or
//	        has decayed past its window
//	tier 3: any other library genre, scored by its size
//
// artist_ids lets the caller skip a genre whose artists mostly repeat one
// already picked (Indie Rock after Alternative Rock).
// $1 user_id.
func (q *Queries) ListGenreMixCandidates(ctx context.Context, userID pgtype.UUID) ([]ListGenreMixCandidatesRow, error) {
	rows, err := q.db.Query(ctx, listGenreMixCandidates, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var items []ListGenreMixCandidatesRow
	for rows.Next() {
		var i ListGenreMixCandidatesRow
		if err := rows.Scan(
			&i.GenreKey,
			&i.Label,
			&i.Tier,
			&i.Score,
			&i.ArtistIds,
		); err != nil {
			return nil, err
		}
		items = append(items, i)
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	return items, nil
}

const listGenreMixTracks = `-- name: ListGenreMixTracks :many
WITH play_counts AS (
    SELECT pe.track_id, COUNT(*) AS c
      FROM play_events pe
     WHERE pe.user_id = $1 AND pe.was_skipped = false
     GROUP BY pe.track_id
),
skip_counts AS (
    SELECT pe.track_id, COUNT(*) AS c
      FROM play_events pe
     WHERE pe.user_id = $1 AND pe.was_skipped = true
     GROUP BY pe.track_id
),
artist_plays AS (
    SELECT t.artist_id,
           COUNT(*) FILTER (WHERE NOT pe.was_skipped) AS plays,
           COUNT(*) FILTER (WHERE pe.was_skipped)     AS skips
      FROM play_events pe
      JOIN tracks t ON t.id = pe.track_id
     WHERE pe.user_id = $1
     GROUP BY t.artist_id
),
artist_likes AS (
    SELECT t.artist_id, COUNT(*) AS likes
      FROM general_likes gl
      JOIN tracks t ON t.id = gl.track_id
     WHERE gl.user_id = $1
     GROUP BY t.artist_id
),
own_artists AS (
    SELECT ap.artist_id FROM artist_plays ap WHERE ap.plays > 0
    UNION
    SELECT al.artist_id FROM artist_likes al
),
artist_sim AS (
    SELECT asim.artist_b_id AS artist_id,
           MAX(LEAST(GREATEST(asim.score, 0), 1)) AS sim
      FROM artist_similarity asim
      JOIN own_artists oa ON oa.artist_id = asim.artist_a_id
     GROUP BY asim.artist_b_id
),
eligible AS (
    SELECT t.id, t.album_id, t.artist_id,
           (COALESCE(pc.c, 0) > 0 OR gl.track_id IS NOT NULL) AS familiar,
           CASE
             WHEN COALESCE(pc.c, 0) > 0 OR gl.track_id IS NOT NULL THEN
               (1 + ln(1 + COALESCE(pc.c, 0)::float8)
                  + CASE WHEN gl.track_id IS NOT NULL THEN 1 ELSE 0 END)
               * ((COALESCE(pc.c, 0) + 1)::float8 / (COALESCE(pc.c, 0) + COALESCE(sc.c, 0) + 1))
             ELSE
               (1 + ln(1 + COALESCE(ap.plays, 0)::float8 + 2 * COALESCE(al.likes, 0)::float8)
                  + 2 * COALESCE(asm.sim, 0))
               * ((COALESCE(ap.plays, 0) + 1)::float8 / (COALESCE(ap.plays, 0) + COALESCE(ap.skips, 0) + 1))
           END::float8 AS weight,
           -- u in (0, 1): the first 32 bits of md5(track, date), shifted off 0.
           ((('x' || substr(md5(t.id::text || $2::text), 1, 8))::bit(32)::bigint)::float8 + 1)
             / 4294967297.0 AS u
      FROM tracks t
      LEFT JOIN play_counts pc ON pc.track_id = t.id
      LEFT JOIN skip_counts sc ON sc.track_id = t.id
      LEFT JOIN general_likes gl ON gl.user_id = $1 AND gl.track_id = t.id
      LEFT JOIN artist_plays ap ON ap.artist_id = t.artist_id
      LEFT JOIN artist_likes al ON al.artist_id = t.artist_id
      LEFT JOIN artist_sim asm ON asm.artist_id = t.artist_id
     WHERE t.missing_since IS NULL   -- never offer a file that is gone
       AND NOT (COALESCE(sc.c, 0) >= 2 AND COALESCE(sc.c, 0) > COALESCE(pc.c, 0))
       AND EXISTS (
           SELECT 1
             FROM regexp_split_to_table(coalesce(t.genre, ''), '[;,]') AS g(g)
            WHERE lower(trim(g.g)) = $3::text
       )
       AND NOT EXISTS (
           SELECT 1 FROM quarantine q
            WHERE q.user_id = $1 AND q.track_id = t.id
       )
),
ranked AS (
    SELECT e.id, e.album_id, e.artist_id, e.familiar,
           -ln(e.u) / e.weight AS draw,
           row_number() OVER (PARTITION BY e.familiar ORDER BY -ln(e.u) / e.weight, e.id) AS rn
      FROM eligible e
)
SELECT r.id, r.album_id, r.artist_id, r.familiar::bool AS familiar
  FROM ranked r
 WHERE r.rn <= 200
 ORDER BY r.familiar DESC, r.draw, r.id
`

type ListGenreMixTracksParams struct {
	UserID   pgtype.UUID
	DateSeed string
	GenreKey string
}

type ListGenreMixTracksRow struct {
	ID       pgtype.UUID
	AlbumID  pgtype.UUID
	ArtistID pgtype.UUID
	Familiar bool
}

// Playable tracks carrying one genre, split into the two halves a genre mix
// blends: familiar (the user has played it through or liked it) and unheard.
// Up to 200 of each, drawn by a weighted lottery seeded with the date, so the
// mix changes day to day, holds still within a day, and leans toward what the
// user likes without becoming the same 50 songs every day.
//
// The lottery is the Efraimidis-Spirakis draw: each track gets
// -ln(u) / weight with u uniform in (0, 1) from md5(track, date), and the
// smallest keys win. A track of weight 3 is three times as likely as one of
// weight 1 to come before it, and every track keeps some chance.
//
// Familiar weight: 1 + ln(1 + plays through) + 1 if liked, times the share of
// its plays that were not skips. A song played 40 times weighs about 4.7, one
// played once about 1.7.
//
// Unheard weight: 1 + ln(1 + the artist's plays through + 2 × its liked
// tracks) + 2 × how similar the artist is to the user's own artists (the best
// artist_similarity score from any artist they have played through or liked,
// 0 to 1), times the share of the artist's plays that were not skips. An
// artist the user has never met weighs 1, so new artists still come up; an
// artist they keep skipping weighs well under 1.
//
// A track the user keeps skipping stays out: twice-skipped and skipped more
// often than played through. The second half of that test keeps a favourite
// with a couple of stray skips in.
func (q *Queries) ListGenreMixTracks(ctx context.Context, arg ListGenreMixTracksParams) ([]ListGenreMixTracksRow, error) {
	rows, err := q.db.Query(ctx, listGenreMixTracks, arg.UserID, arg.DateSeed, arg.GenreKey)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var items []ListGenreMixTracksRow
	for rows.Next() {
		var i ListGenreMixTracksRow
		if err := rows.Scan(
			&i.ID,
			&i.AlbumID,
			&i.ArtistID,
			&i.Familiar,
		); err != nil {
			return nil, err
		}
		items = append(items, i)
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	return items, nil
}