CUB-183: SQLite schema migration + DB init

internal/db/db.go

@@ -1,2 +1,135 @@
 // Package db provides SQLite database initialization and schema management.
 package db
+
+import (
+	"database/sql"
+	_ "embed"
+	"log"
+	"os"
+	"path/filepath"
+
+	_ "modernc.org/sqlite"
+)
+
+//go:embed migrations/001_create_tables.sql
+var migration001 string
+
+// DB wraps the sql.DB with connection-level settings.
+type DB struct {
+	*sql.DB
+}
+
+// Open opens the SQLite database at the given path, enables WAL mode,
+// and runs all migrations if the tables don't exist yet.
+func Open(path string) (*DB, error) {
+	// Ensure the directory exists
+	dir := filepath.Dir(path)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return nil, err
+	}
+
+	db, err := sql.Open("sqlite", path)
+	if err != nil {
+		return nil, err
+	}
+
+	// Enable WAL for concurrent read/write performance
+	if _, err := db.Exec("PRAGMA journal_mode=WAL"); err != nil {
+		db.Close()
+		return nil, err
+	}
+
+	// Enable foreign keys
+	if _, err := db.Exec("PRAGMA foreign_keys=ON"); err != nil {
+		db.Close()
+		return nil, err
+	}
+
+	// Check if tables already exist (idempotent migration)
+	var count int
+	if err := db.QueryRow(`
+		SELECT COUNT(*) FROM sqlite_master
+		WHERE type='table' AND name IN ('cameras', 'status_logs', 'recording_events', 'settings')
+	`).Scan(&count); err != nil {
+		db.Close()
+		return nil, err
+	}
+
+	if count < 4 {
+		log.Printf("Running migrations for %s...", path)
+		if err := migrate(db, migration001); err != nil {
+			db.Close()
+			return nil, err
+		}
+		log.Println("Migrations complete")
+	}
+
+	return &DB{db}, nil
+}
+
+// migrate executes a SQL migration string.
+func migrate(db *sql.DB, sql string) error {
+	// Split on semicolons to handle multiple statements
+	statements := splitSQL(sql)
+	for _, stmt := range statements {
+		stmt = stripWhitespace(stmt)
+		if stmt == "" {
+			continue
+		}
+		if _, err := db.Exec(stmt); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// splitSQL splits a SQL string on semicolons, respecting quoted strings.
+func splitSQL(sql string) []string {
+	var stmts []string
+	var current string
+	inQuote := false
+	quoteChar := rune(0)
+
+	for _, r := range sql {
+		if inQuote {
+			current += string(r)
+			if r == quoteChar {
+				inQuote = false
+			}
+			continue
+		}
+		switch r {
+		case '"', '\'', '`':
+			inQuote = true
+			quoteChar = r
+			current += string(r)
+		case ';':
+			stmts = append(stmts, current)
+			current = ""
+		default:
+			current += string(r)
+		}
+	}
+	if len(current) > 0 {
+		stmts = append(stmts, current)
+	}
+	return stmts
+}
+
+// stripWhitespace removes leading/trailing whitespace and normalizes newlines.
+func stripWhitespace(s string) string {
+	result := ""
+	runningSpace := false
+	for _, r := range s {
+		if r == ' ' || r == '\t' || r == '\n' || r == '\r' {
+			if !runningSpace {
+				result += " "
+				runningSpace = true
+			}
+		} else {
+			result += string(r)
+			runningSpace = false
+		}
+	}
+	return result
+}