Adding implementation for sqlite database

internal/store/sqlite/sqlite.go

@@ -4,6 +4,9 @@ import (
 	"context"
 	"database/sql"
 	"fmt"
+	"time"
+
+	"modernc.org/sqlite"
 )
 
 const sqlSet = `
@@ -17,9 +20,64 @@ type SQLiteStore struct {
 }
 
 func NewSQLiteStore(ctx context.Context, dbPath string) (*SQLiteStore, error) {
-	return nil, fmt.Errorf("not implemented")
+	sqliteDB := &SQLiteStore{}
+
+	sqlite.RegisterConnectionHook(func(conn sqlite.ExecQuerierContext, _ string) error {
+		_, err := conn.ExecContext(ctx, sqlSet, nil)
+		return err
+	})
+
+	write, err := sql.Open("sqlite", "file:"+dbPath)
+	if err != nil {
+		return nil, err
+	}
+	err = write.PingContext(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to ping database: %w", err)
+	}
+	// only a single writer ever, no concurrency I don't trust it
+	write.SetMaxOpenConns(1)
+	write.SetConnMaxIdleTime(time.Minute)
+
+	read, err := sql.Open("sqlite", "file:"+dbPath)
+	if err != nil {
+		return nil, err
+	}
+	err = read.PingContext(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to ping database: %w", err)
+	}
+	// readers can be concurrent
+	read.SetMaxOpenConns(100)
+	read.SetConnMaxIdleTime(time.Minute)
+
+	sqliteDB.read = read
+	sqliteDB.write = write
+
+	err = sqliteDB.validateSchema(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to validate schema: %w", err)
+	}
+
+	return sqliteDB, nil
 }
 
 func (s *SQLiteStore) Close() error {
-	return fmt.Errorf("not implemented")
+	readErr := s.read.Close()
+	writeErr := s.write.Close()
+	if readErr != nil || writeErr != nil {
+		return fmt.Errorf("failed to close connections: read error: %v, write error: %v", readErr, writeErr)
+	}
+	return nil
+}
+
+func (s *SQLiteStore) validateSchema(ctx context.Context) error {
+	_, err := s.write.ExecContext(ctx, `
+		CREATE TABLE IF NOT EXISTS notes (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			last_update TIMESTAMP NOT NULL,
+			content TEXT NOT NULL
+		);
+	`, nil)
+	return err
 }