first commit

2026-08-09 18:03:09 +01:00
commit d7ca591b76
169 changed files with 51272 additions and 0 deletions
@@ -0,0 +1,158 @@
+// Package db wraps database/sql with the gomail schema. No ORM — raw SQL with
+// prepared statements only, per the project's minimal-dependency principle.
+package db
+
+import (
+	"database/sql"
+	"fmt"
+	"log/slog"
+	"strings"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// DB wraps *sql.DB with the driver name (some queries need driver-specific SQL,
+// e.g. placeholder syntax differs between sqlite/postgres/mysql).
+type DB struct {
+	*sql.DB
+	Driver string
+}
+
+// Open connects to the database using the configured driver.
+// SQLite is always available; postgres and mysql require build tags:
+//
+//	go build -tags postgres .
+//	go build -tags mysql .
+func Open(driver, dsn string) (*DB, error) {
+	d := strings.ToLower(driver)
+
+	var sqlDriverName string
+	switch d {
+	case "sqlite", "":
+		sqlDriverName = "sqlite3"
+		d = "sqlite"
+	default:
+		name, ok := driverRegistry[d]
+		if !ok {
+			available := []string{"sqlite"}
+			for k := range driverRegistry {
+				available = append(available, k)
+			}
+			return nil, fmt.Errorf("driver %q not compiled in; rebuild with -tags %s. Available: %v", driver, driver, available)
+		}
+		sqlDriverName = name
+	}
+
+	sqlDB, err := sql.Open(sqlDriverName, dsn)
+	if err != nil {
+		return nil, fmt.Errorf("opening database: %w", err)
+	}
+
+	if d == "sqlite" {
+		// SQLite doesn't handle concurrent writers well — serialize via single conn.
+		sqlDB.SetMaxOpenConns(1)
+		if _, err := sqlDB.Exec("PRAGMA journal_mode=WAL"); err != nil {
+			return nil, fmt.Errorf("enabling WAL mode: %w", err)
+		}
+		if _, err := sqlDB.Exec("PRAGMA foreign_keys=ON"); err != nil {
+			return nil, fmt.Errorf("enabling foreign keys: %w", err)
+		}
+		if _, err := sqlDB.Exec("PRAGMA busy_timeout=5000"); err != nil {
+			return nil, fmt.Errorf("setting busy timeout: %w", err)
+		}
+	}
+
+	if err := sqlDB.Ping(); err != nil {
+		return nil, fmt.Errorf("ping database: %w", err)
+	}
+
+	return &DB{DB: sqlDB, Driver: d}, nil
+}
+
+// driverRegistry is populated by build-tag-gated driver_*.go files
+// (driver_postgres.go, driver_mysql.go) via init().
+var driverRegistry = map[string]string{}
+
+func registerDriver(name, sqlDriverName string) {
+	driverRegistry[strings.ToLower(name)] = sqlDriverName
+}
+
+// Migrate runs all pending schema migrations in order. Migrations are
+// idempotent (CREATE TABLE IF NOT EXISTS) so this is always safe to call at
+// startup.
+func (db *DB) Migrate() error {
+	slog.Info("running database migrations")
+
+	if _, err := db.Exec(migrationsTableSQL[db.Driver]); err != nil {
+		return fmt.Errorf("creating migrations table: %w", err)
+	}
+
+	for _, m := range migrations {
+		applied, err := db.migrationApplied(m.name)
+		if err != nil {
+			return fmt.Errorf("checking migration %s: %w", m.name, err)
+		}
+		if applied {
+			continue
+		}
+
+		stmt := m.sql[db.Driver]
+		if stmt == "" {
+			stmt = m.sql["sqlite"] // fall back — most DDL is portable enough via driver quirks handled per-migration
+		}
+
+		slog.Info("applying migration", "name", m.name)
+		tx, err := db.Begin()
+		if err != nil {
+			return fmt.Errorf("begin tx for %s: %w", m.name, err)
+		}
+		if _, err := tx.Exec(stmt); err != nil {
+			tx.Rollback()
+			return fmt.Errorf("applying migration %s: %w", m.name, err)
+		}
+		if _, err := tx.Exec(db.insertMigrationSQL(), m.name); err != nil {
+			tx.Rollback()
+			return fmt.Errorf("recording migration %s: %w", m.name, err)
+		}
+		if err := tx.Commit(); err != nil {
+			return fmt.Errorf("commit migration %s: %w", m.name, err)
+		}
+	}
+
+	slog.Info("migrations complete", "count", len(migrations))
+	return nil
+}
+
+func (db *DB) migrationApplied(name string) (bool, error) {
+	var count int
+	err := db.QueryRow("SELECT COUNT(*) FROM schema_migrations WHERE name = "+db.placeholder(1), name).Scan(&count)
+	return count > 0, err
+}
+
+func (db *DB) insertMigrationSQL() string {
+	return "INSERT INTO schema_migrations (name, applied_at) VALUES (" + db.placeholder(1) + ", CURRENT_TIMESTAMP)"
+}
+
+// placeholder returns the driver-appropriate positional parameter syntax.
+// sqlite/mysql use "?", postgres uses "$1", "$2", ...
+func (db *DB) placeholder(n int) string {
+	if db.Driver == "postgres" {
+		return fmt.Sprintf("$%d", n)
+	}
+	return "?"
+}
+
+var migrationsTableSQL = map[string]string{
+	"sqlite": `CREATE TABLE IF NOT EXISTS schema_migrations (
+		name TEXT PRIMARY KEY,
+		applied_at DATETIME NOT NULL
+	)`,
+	"postgres": `CREATE TABLE IF NOT EXISTS schema_migrations (
+		name TEXT PRIMARY KEY,
+		applied_at TIMESTAMPTZ NOT NULL
+	)`,
+	"mysql": `CREATE TABLE IF NOT EXISTS schema_migrations (
+		name VARCHAR(255) PRIMARY KEY,
+		applied_at DATETIME NOT NULL
+	)`,
+}