Store unfinished tasks on disks

internal/db/db.go

@@ -2,8 +2,11 @@ package db
 
 import (
 	"database/sql"
+	"encoding/json"
 	"time"
 
+	"jukebox_maker/internal/task"
+
 	_ "modernc.org/sqlite"
 )
 
@@ -18,6 +21,11 @@ type CopyRecord struct {
 	CopiedAt   time.Time
 }
 
+type TaskRecord struct {
+	Task    task.Task
+	Payload json.RawMessage
+}
+
 func Open(path string) (*DB, error) {
 	conn, err := sql.Open("sqlite", path+"?_journal=WAL&_timeout=5000")
 	if err != nil {
@@ -51,6 +59,22 @@ func (d *DB) migrate() error {
 			disk_id        TEXT PRIMARY KEY,
 			last_copied_at DATETIME NOT NULL
 		);
+		CREATE TABLE IF NOT EXISTS tasks (
+			id         TEXT PRIMARY KEY,
+			disk_id    TEXT NOT NULL,
+			type       TEXT NOT NULL,
+			status     TEXT NOT NULL,
+			phase      TEXT NOT NULL DEFAULT 'queued',
+			progress   INTEGER NOT NULL DEFAULT 0,
+			message    TEXT NOT NULL DEFAULT '',
+			speed_bps  INTEGER NOT NULL DEFAULT 0,
+			eta_sec    INTEGER NOT NULL DEFAULT 0,
+			error      TEXT NOT NULL DEFAULT '',
+			payload    TEXT NOT NULL DEFAULT '{}',
+			created_at DATETIME NOT NULL,
+			updated_at DATETIME NOT NULL
+		);
+		CREATE INDEX IF NOT EXISTS idx_tasks_status_updated ON tasks (status, updated_at);
 	`)
 	return err
 }
@@ -129,3 +153,94 @@ func (d *DB) LastCopiedAt(diskID string) (time.Time, bool, error) {
 	}
 	return t, true, nil
 }
+
+func (d *DB) UpsertTask(t task.Task, payload json.RawMessage) error {
+	if payload == nil {
+		payload = json.RawMessage(`{}`)
+	}
+	_, err := d.sql.Exec(
+		`INSERT INTO tasks (id, disk_id, type, status, phase, progress, message, speed_bps, eta_sec, error, payload, created_at, updated_at)
+		 VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+		 ON CONFLICT(id) DO UPDATE SET
+		 status=excluded.status,
+		 phase=excluded.phase,
+		 progress=excluded.progress,
+		 message=excluded.message,
+		 speed_bps=excluded.speed_bps,
+		 eta_sec=excluded.eta_sec,
+		 error=excluded.error,
+		 payload=excluded.payload,
+		 updated_at=excluded.updated_at`,
+		t.ID, t.DiskID, t.Type, t.Status, t.Phase, t.Progress, t.Message, t.SpeedBPS, t.ETASec, t.Error,
+		string(payload), t.CreatedAt.Format(time.RFC3339), t.UpdatedAt.Format(time.RFC3339),
+	)
+	return err
+}
+
+func (d *DB) UpdateTask(t task.Task) error {
+	_, err := d.sql.Exec(
+		`UPDATE tasks
+		 SET status=?, phase=?, progress=?, message=?, speed_bps=?, eta_sec=?, error=?, updated_at=?
+		 WHERE id=?`,
+		t.Status, t.Phase, t.Progress, t.Message, t.SpeedBPS, t.ETASec, t.Error, t.UpdatedAt.Format(time.RFC3339), t.ID,
+	)
+	return err
+}
+
+func (d *DB) ActiveTask() (*TaskRecord, bool, error) {
+	row := d.sql.QueryRow(
+		`SELECT id, disk_id, type, status, phase, progress, message, speed_bps, eta_sec, error, payload, created_at, updated_at
+		 FROM tasks
+		 WHERE status IN ('queued','running')
+		 ORDER BY updated_at DESC
+		 LIMIT 1`,
+	)
+	rec, err := scanTaskRecord(row)
+	if err == sql.ErrNoRows {
+		return nil, false, nil
+	}
+	if err != nil {
+		return nil, false, err
+	}
+	return rec, true, nil
+}
+
+type scanner interface {
+	Scan(dest ...any) error
+}
+
+func scanTaskRecord(s scanner) (*TaskRecord, error) {
+	var rec TaskRecord
+	var payloadRaw, createdAtRaw, updatedAtRaw string
+	err := s.Scan(
+		&rec.Task.ID,
+		&rec.Task.DiskID,
+		&rec.Task.Type,
+		&rec.Task.Status,
+		&rec.Task.Phase,
+		&rec.Task.Progress,
+		&rec.Task.Message,
+		&rec.Task.SpeedBPS,
+		&rec.Task.ETASec,
+		&rec.Task.Error,
+		&payloadRaw,
+		&createdAtRaw,
+		&updatedAtRaw,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	createdAt, err := time.Parse(time.RFC3339, createdAtRaw)
+	if err != nil {
+		return nil, err
+	}
+	updatedAt, err := time.Parse(time.RFC3339, updatedAtRaw)
+	if err != nil {
+		return nil, err
+	}
+	rec.Task.CreatedAt = createdAt
+	rec.Task.UpdatedAt = updatedAt
+	rec.Payload = json.RawMessage(payloadRaw)
+	return &rec, nil
+}