|
| 1 | +package challenges |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "errors" |
| 6 | + "fmt" |
| 7 | + "time" |
| 8 | + |
| 9 | + "github.com/jackc/pgx/v5" |
| 10 | +) |
| 11 | + |
| 12 | +// ListenStreakProcessor implements challenge "e" — daily listen streak. |
| 13 | +// Mirrors apps' listen_streak_endless_challenge.py. |
| 14 | +// |
| 15 | +// State lives in `challenge_listen_streak` (last_listen_date, listen_streak). |
| 16 | +// Rules (per apps): |
| 17 | +// - First listen: streak = 1, last_listen_date = play timestamp. |
| 18 | +// - Subsequent listen >= 16h after last_listen_date: advance streak by 1. |
| 19 | +// - If >= 48h gap: reset streak to 1. |
| 20 | +// - Otherwise (<16h): ignore. |
| 21 | +// |
| 22 | +// user_challenges rows have specifier "<hex_user_id><YYYYMMDDHH>". When the |
| 23 | +// streak crosses 7 days the row is completed; subsequent "endless" rows are |
| 24 | +// minted at amount=1 each. |
| 25 | +// |
| 26 | +// NOTE: in challenges.json this challenge is currently active=false, so the |
| 27 | +// processor is a no-op at present. Reconcile still does the right thing if |
| 28 | +// it gets enabled. |
| 29 | +type ListenStreakProcessor struct{} |
| 30 | + |
| 31 | +func (p *ListenStreakProcessor) ChallengeID() string { return "e" } |
| 32 | + |
| 33 | +const ( |
| 34 | + listenStreakNextWindow = 16 * time.Hour |
| 35 | + listenStreakBrokenWindow = 48 * time.Hour |
| 36 | + listenStreakTarget = int32(7) |
| 37 | +) |
| 38 | + |
| 39 | +const listenStreakCheckpoint = "challenges:e:last_play_id" |
| 40 | + |
| 41 | +// listenStreakPlay is one row from the plays scan. |
| 42 | +type listenStreakPlay struct { |
| 43 | + id int64 |
| 44 | + userID int64 |
| 45 | + createdAt time.Time |
| 46 | +} |
| 47 | + |
| 48 | +func (p *ListenStreakProcessor) Reconcile(ctx context.Context, tx pgx.Tx) error { |
| 49 | + c, ok, err := LoadChallenge(ctx, tx, p.ChallengeID()) |
| 50 | + if err != nil { |
| 51 | + return fmt.Errorf("load challenge: %w", err) |
| 52 | + } |
| 53 | + if !ok || !c.Active { |
| 54 | + return nil |
| 55 | + } |
| 56 | + amount := c.AmountInt() |
| 57 | + |
| 58 | + prev, err := readCheckpointInt(ctx, tx, listenStreakCheckpoint) |
| 59 | + if err != nil { |
| 60 | + return fmt.Errorf("read checkpoint: %w", err) |
| 61 | + } |
| 62 | + |
| 63 | + // Pull new plays ordered by id. We deliberately use id ordering rather |
| 64 | + // than created_at because id is monotonic per insert and matches the |
| 65 | + // invariant apps' Python pipeline assumes (plays are processed in |
| 66 | + // arrival order). |
| 67 | + rows, err := tx.Query(ctx, ` |
| 68 | + SELECT id, user_id, created_at |
| 69 | + FROM plays |
| 70 | + WHERE id > $1 AND user_id IS NOT NULL |
| 71 | + ORDER BY id ASC |
| 72 | + LIMIT 50000 |
| 73 | + `, prev) |
| 74 | + if err != nil { |
| 75 | + return fmt.Errorf("scan plays: %w", err) |
| 76 | + } |
| 77 | + var plays []listenStreakPlay |
| 78 | + for rows.Next() { |
| 79 | + var r listenStreakPlay |
| 80 | + if err := rows.Scan(&r.id, &r.userID, &r.createdAt); err != nil { |
| 81 | + rows.Close() |
| 82 | + return err |
| 83 | + } |
| 84 | + plays = append(plays, r) |
| 85 | + } |
| 86 | + rows.Close() |
| 87 | + if err := rows.Err(); err != nil { |
| 88 | + return err |
| 89 | + } |
| 90 | + if len(plays) == 0 { |
| 91 | + return nil |
| 92 | + } |
| 93 | + |
| 94 | + // Apply transitions in-process. We load existing streak state for |
| 95 | + // users with new plays in one go. |
| 96 | + userIDs := uniqueUserIDs(plays) |
| 97 | + type streakState struct { |
| 98 | + lastListen *time.Time |
| 99 | + streak int32 |
| 100 | + } |
| 101 | + state := make(map[int64]*streakState, len(userIDs)) |
| 102 | + |
| 103 | + srows, err := tx.Query(ctx, ` |
| 104 | + SELECT user_id, last_listen_date, listen_streak |
| 105 | + FROM challenge_listen_streak |
| 106 | + WHERE user_id = ANY($1) |
| 107 | + `, userIDs) |
| 108 | + if err != nil { |
| 109 | + return fmt.Errorf("load streak state: %w", err) |
| 110 | + } |
| 111 | + for srows.Next() { |
| 112 | + var uid int64 |
| 113 | + var last *time.Time |
| 114 | + var streak int32 |
| 115 | + if err := srows.Scan(&uid, &last, &streak); err != nil { |
| 116 | + srows.Close() |
| 117 | + return err |
| 118 | + } |
| 119 | + state[uid] = &streakState{lastListen: last, streak: streak} |
| 120 | + } |
| 121 | + srows.Close() |
| 122 | + if err := srows.Err(); err != nil { |
| 123 | + return err |
| 124 | + } |
| 125 | + |
| 126 | + // Walk plays in order, applying the transition rules per user. Each |
| 127 | + // play either advances or resets a streak — we batch the writes after |
| 128 | + // the simulation. |
| 129 | + type advance struct { |
| 130 | + newStreak int32 |
| 131 | + whenLogged time.Time |
| 132 | + } |
| 133 | + advancesByUser := make(map[int64][]advance) |
| 134 | + |
| 135 | + for _, pl := range plays { |
| 136 | + s, ok := state[pl.userID] |
| 137 | + if !ok { |
| 138 | + s = &streakState{lastListen: nil, streak: 0} |
| 139 | + state[pl.userID] = s |
| 140 | + } |
| 141 | + if s.lastListen == nil { |
| 142 | + s.streak = 1 |
| 143 | + t := pl.createdAt |
| 144 | + s.lastListen = &t |
| 145 | + advancesByUser[pl.userID] = append(advancesByUser[pl.userID], advance{1, pl.createdAt}) |
| 146 | + continue |
| 147 | + } |
| 148 | + gap := pl.createdAt.Sub(*s.lastListen) |
| 149 | + if gap < listenStreakNextWindow { |
| 150 | + continue // too soon, ignore |
| 151 | + } |
| 152 | + if gap >= listenStreakBrokenWindow { |
| 153 | + s.streak = 1 |
| 154 | + } else { |
| 155 | + s.streak++ |
| 156 | + } |
| 157 | + t := pl.createdAt |
| 158 | + s.lastListen = &t |
| 159 | + advancesByUser[pl.userID] = append(advancesByUser[pl.userID], advance{s.streak, pl.createdAt}) |
| 160 | + } |
| 161 | + |
| 162 | + // Write updated streak state per user. |
| 163 | + for userID, s := range state { |
| 164 | + if _, err := tx.Exec(ctx, ` |
| 165 | + INSERT INTO challenge_listen_streak (user_id, last_listen_date, listen_streak) |
| 166 | + VALUES ($1, $2, $3) |
| 167 | + ON CONFLICT (user_id) DO UPDATE SET |
| 168 | + last_listen_date = EXCLUDED.last_listen_date, |
| 169 | + listen_streak = EXCLUDED.listen_streak |
| 170 | + `, userID, s.lastListen, s.streak); err != nil { |
| 171 | + return fmt.Errorf("upsert streak state: %w", err) |
| 172 | + } |
| 173 | + } |
| 174 | + |
| 175 | + // For each advance, mint or update the relevant user_challenge row. |
| 176 | + // Specifier format follows apps' new post-cutover format: |
| 177 | + // first 7 days: "<hex>:YYYYMMDDHH" of *new streak boundary* |
| 178 | + // endless : same, one row per day after 7 |
| 179 | + for userID, advances := range advancesByUser { |
| 180 | + for _, a := range advances { |
| 181 | + specifier := fmt.Sprintf("%x%s", userID, a.whenLogged.UTC().Format("2006010215")) |
| 182 | + // In the first-7-day window, current_step_count = streak (1..7), |
| 183 | + // is_complete when streak >= 7. After 7, this row is the |
| 184 | + // endless +1-per-day reward (step_count = 1, amount = 1). |
| 185 | + var stepCount int32 = listenStreakTarget |
| 186 | + report := a.newStreak |
| 187 | + if a.newStreak > listenStreakTarget { |
| 188 | + stepCount = 1 |
| 189 | + report = 1 |
| 190 | + } |
| 191 | + if err := UpsertUserChallenge(ctx, tx, |
| 192 | + p.ChallengeID(), specifier, userID, report, stepCount, amount, |
| 193 | + ); err != nil { |
| 194 | + return fmt.Errorf("upsert listen-streak user_challenge: %w", err) |
| 195 | + } |
| 196 | + } |
| 197 | + } |
| 198 | + |
| 199 | + // Advance checkpoint to the last play id we processed. |
| 200 | + if err := writeCheckpointInt(ctx, tx, listenStreakCheckpoint, plays[len(plays)-1].id); err != nil { |
| 201 | + return fmt.Errorf("save checkpoint: %w", err) |
| 202 | + } |
| 203 | + return nil |
| 204 | +} |
| 205 | + |
| 206 | +func uniqueUserIDs(plays []listenStreakPlay) []int64 { |
| 207 | + seen := make(map[int64]struct{}, len(plays)) |
| 208 | + out := make([]int64, 0, len(plays)) |
| 209 | + for _, p := range plays { |
| 210 | + if _, ok := seen[p.userID]; ok { |
| 211 | + continue |
| 212 | + } |
| 213 | + seen[p.userID] = struct{}{} |
| 214 | + out = append(out, p.userID) |
| 215 | + } |
| 216 | + return out |
| 217 | +} |
| 218 | + |
| 219 | +// readCheckpointInt reads a named integer checkpoint from indexing_checkpoints, |
| 220 | +// returning 0 if absent. |
| 221 | +func readCheckpointInt(ctx context.Context, tx pgx.Tx, name string) (int64, error) { |
| 222 | + var v int64 |
| 223 | + err := tx.QueryRow(ctx, "SELECT last_checkpoint FROM indexing_checkpoints WHERE tablename = $1", name).Scan(&v) |
| 224 | + if errors.Is(err, pgx.ErrNoRows) { |
| 225 | + return 0, nil |
| 226 | + } |
| 227 | + return v, err |
| 228 | +} |
| 229 | + |
| 230 | +func writeCheckpointInt(ctx context.Context, tx pgx.Tx, name string, value int64) error { |
| 231 | + _, err := tx.Exec(ctx, ` |
| 232 | + INSERT INTO indexing_checkpoints (tablename, last_checkpoint) |
| 233 | + VALUES ($1, $2) |
| 234 | + ON CONFLICT (tablename) DO UPDATE SET last_checkpoint = EXCLUDED.last_checkpoint |
| 235 | + `, name, value) |
| 236 | + return err |
| 237 | +} |
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