package database

import (
	"database/sql"
	"os"
	"testing"

	"github.com/stretchr/testify/mock"
)

// Mock for the database service
type MockService struct {
	mock.Mock
}

func (m *MockService) Health() map[string]map[string]string {
	args := m.Called()
	return args.Get(0).(map[string]map[string]string)
}

func (m *MockService) GetDB(name string) (*sql.DB, error) {
	args := m.Called(name)
	return args.Get(0).(*sql.DB), args.Error(1)
}

func (m *MockService) Close() error {
	return m.Called().Error(0)
}

func (m *MockService) ListDBs() []string {
	args := m.Called()
	return args.Get(0).([]string)
}

func (m *MockService) GetDBType(name string) (DatabaseType, error) {
	args := m.Called(name)
	return args.Get(0).(DatabaseType), args.Error(1)
}

func TestNew(t *testing.T) {
	srv := New()
	if srv == nil {
		t.Fatal("New() returned nil")
	}
}

func TestHealth(t *testing.T) {
	srv := New()

	stats := srv.Health()

	// Since we don't have any databases configured in test, we expect empty stats
	if len(stats) == 0 {
		t.Log("No databases configured, health check returns empty stats")
		return
	}

	// If we have databases, check their health
	for dbName, dbStats := range stats {
		if dbStats["status"] != "up" {
			t.Errorf("database %s status is not up: %s", dbName, dbStats["status"])
		}
		if err, ok := dbStats["error"]; ok && err != "" {
			t.Errorf("database %s has error: %s", dbName, err)
		}
	}
}

func TestClose(t *testing.T) {
	srv := New()

	if srv.Close() != nil {
		t.Fatalf("expected Close() to return nil")
	}
}

// Test for loading database configurations
func TestLoadDatabaseConfigs(t *testing.T) {
	// Set environment variables for testing
	os.Setenv("DB_TEST_TYPE", "postgres")
	os.Setenv("DB_TEST_HOST", "localhost")
	os.Setenv("DB_TEST_PORT", "5432")
	os.Setenv("DB_TEST_DATABASE", "testdb")
	os.Setenv("DB_TEST_USERNAME", "testuser")
	os.Setenv("DB_TEST_PASSWORD", "testpass")

	configs := loadDatabaseConfigs()
	if len(configs) == 0 {
		t.Fatal("Expected database configurations to be loaded")
	}

	if configs[0].Type != "postgres" {
		t.Errorf("Expected database type to be postgres, got %s", configs[0].Type)
	}
}

// Test for connection pooling settings
func TestConnectionPooling(t *testing.T) {
	srv := New()
	// Check health after loading configurations
	stats := srv.Health()
	if len(stats) == 0 {
		t.Fatal("Expected databases to be configured, but found none")
	}

	db, err := srv.GetDB("testdb")
	if err != nil {
		t.Fatalf("Failed to get database: %v", err)
	}

	if db.Stats().MaxOpenConnections != 10 {
		t.Errorf("Expected max open connections to be 10, got %d", db.Stats().MaxOpenConnections)
	}
}

// Test for error handling during connection
func TestErrorHandling(t *testing.T) {
	srv := New()
	// Check health to see if it handles errors
	stats := srv.Health()
	if len(stats) > 0 {
		t.Fatal("Expected no databases to be configured, but found some")
	}
}