package fen

import (
	"fmt"
	"mime/multipart"
	"reflect"
	"strings"
	"sync"

	"github.com/gofiber/fiber/v3"
	"github.com/pkg/errors"
)

func File[T any](key string) func(fiber.Ctx) (*multipart.FileHeader, error) {
	return func(ctx fiber.Ctx) (*multipart.FileHeader, error) {
		_ = new(T)
		return ctx.FormFile(key)
	}
}

func Local[T any](key any) func(fiber.Ctx) (T, error) {
	return func(ctx fiber.Ctx) (T, error) {
		v := fiber.Locals[T](ctx, key)
		return v, nil
	}
}

func Path[T fiber.GenericType](key string) func(fiber.Ctx) (T, error) {
	return func(ctx fiber.Ctx) (T, error) {
		v := fiber.Params[T](ctx, key)
		return v, nil
	}
}

func PathParam[T fiber.GenericType](name string) func(fiber.Ctx) (T, error) {
	return func(ctx fiber.Ctx) (T, error) {
		v := fiber.Params[T](ctx, name)
		return v, nil
	}
}

func Body[T any](name string) func(fiber.Ctx) (*T, error) {
	return func(ctx fiber.Ctx) (*T, error) {
		p := new(T)
		if err := ctx.Bind().Body(p); err != nil {
			return nil, errors.Wrapf(err, "body: %s", name)
		}

		return p, nil
	}
}

func QueryParam[T fiber.GenericType](key string) func(fiber.Ctx) (T, error) {
	return func(ctx fiber.Ctx) (T, error) {
		v := fiber.Query[T](ctx, key)
		return v, nil
	}
}

func Query[T any](name string) func(fiber.Ctx) (*T, error) {
	return func(ctx fiber.Ctx) (*T, error) {
		p := new(T)
		if err := ctx.Bind().Query(p); err != nil {
			return nil, errors.Wrapf(err, "query: %s", name)
		}

		return p, nil
	}
}

func Header[T any](name string) func(fiber.Ctx) (*T, error) {
	return func(ctx fiber.Ctx) (*T, error) {
		p := new(T)
		err := ctx.Bind().Header(p)
		if err != nil {
			return nil, errors.Wrapf(err, "header: %s", name)
		}

		return p, nil
	}
}

func Cookie[T any](name string) func(fiber.Ctx) (*T, error) {
	return func(ctx fiber.Ctx) (*T, error) {
		p := new(T)
		if err := ctx.Bind().Cookie(p); err != nil {
			return nil, errors.Wrapf(err, "cookie: %s", name)
		}

		return p, nil
	}
}

func CookieParam(name string) func(fiber.Ctx) (string, error) {
	return func(ctx fiber.Ctx) (string, error) {
		return ctx.Cookies(name), nil
	}
}

// ModelByPath creates a model parameter binder that queries a model instance using a path parameter
// This provides a unified way to bind model parameters similar to other parameter types
func ModelByPath[T any, K fiber.GenericType](queryFunc func(context interface{}) interface{}, field, pathKey string) func(fiber.Ctx) (*T, error) {
	return func(ctx fiber.Ctx) (*T, error) {
		v := fiber.Params[K](ctx, pathKey)

		// Get query context with the provided context
		queryWithContext := queryFunc(ctx)

		// Use reflection to call Where and First methods
		queryValue := reflect.ValueOf(queryWithContext)

		// Get Where method
		whereMethod := queryValue.MethodByName("Where")
		if !whereMethod.IsValid() {
			return nil, fmt.Errorf("query object does not have Where method")
		}

		// Get field object by field name
		// If queryValue is a pointer, we need to get the element it points to
		var queryStruct reflect.Value
		if queryValue.Kind() == reflect.Ptr {
			queryStruct = queryValue.Elem()
		} else {
			queryStruct = queryValue
		}

		fieldValue := queryStruct.FieldByName(field)
		if !fieldValue.IsValid() {
			// Try with capitalized first letter for Go field naming convention
			capitalizedField := ""
			if len(field) > 0 {
				capitalizedField = strings.ToUpper(field[:1]) + field[1:]
			}
			fieldValue = queryStruct.FieldByName(capitalizedField)
			if !fieldValue.IsValid() {
				return nil, fmt.Errorf("query object does not have field '%s' or '%s'", field, capitalizedField)
			}
		}

		// Get Eq method from the field
		eqMethod := fieldValue.MethodByName("Eq")
		if !eqMethod.IsValid() {
			return nil, fmt.Errorf("field '%s' does not have Eq method", field)
		}

		// Convert paramValue to the appropriate type based on field type
		var paramValueReflect reflect.Value
		fieldType := fieldValue.Type()

		// Check if it's a field.String type
		if fieldType.String() == "field.String" {
			paramValueReflect = reflect.ValueOf(fmt.Sprintf("%v", v))
		} else if fieldType.String() == "field.Int32" || fieldType.String() == "field.Int" {
			// Use reflection to handle the generic type parameter
			vValue := reflect.ValueOf(v)
			switch vValue.Kind() {
			case reflect.Int, reflect.Int32:
				paramValueReflect = vValue
			case reflect.String:
				strVal := vValue.String()
				var intVal int
				_, err := fmt.Sscanf(strVal, "%d", &intVal)
				if err != nil {
					return nil, fmt.Errorf("failed to convert '%s' to int: %v", strVal, err)
				}
				paramValueReflect = reflect.ValueOf(intVal)
			default:
				return nil, fmt.Errorf("unsupported param type for int field: %v", vValue.Kind())
			}
		} else {
			// Fallback to basic kind-based detection
			switch fieldValue.Kind() {
			case reflect.String:
				paramValueReflect = reflect.ValueOf(fmt.Sprintf("%v", v))
			case reflect.Int, reflect.Int32:
				// Use reflection to handle the generic type parameter
				vValue := reflect.ValueOf(v)
				switch vValue.Kind() {
				case reflect.Int, reflect.Int32:
					paramValueReflect = vValue
				case reflect.String:
					strVal := vValue.String()
					var intVal int
					_, err := fmt.Sscanf(strVal, "%d", &intVal)
					if err != nil {
						return nil, fmt.Errorf("failed to convert '%s' to int: %v", strVal, err)
					}
					paramValueReflect = reflect.ValueOf(intVal)
				default:
					return nil, fmt.Errorf("unsupported param type for int field: %v", vValue.Kind())
				}
			default:
				return nil, fmt.Errorf("unsupported field type: %v (kind: %v)", fieldType, fieldValue.Kind())
			}
		}

		// Call Eq method to create condition
		conditionResult := eqMethod.Call([]reflect.Value{paramValueReflect})
		if len(conditionResult) == 0 {
			return nil, fmt.Errorf("Eq method returned no result")
		}

		// Call Where with the condition
		whereResult := whereMethod.Call([]reflect.Value{conditionResult[0]})
		if len(whereResult) == 0 {
			return nil, fmt.Errorf("Where method returned no result")
		}

		whereQuery := whereResult[0]

		// Get First method
		firstMethod := whereQuery.MethodByName("First")
		if !firstMethod.IsValid() {
			return nil, fmt.Errorf("query object does not have First method")
		}

		// Call First()
		firstResult := firstMethod.Call(nil)
		if len(firstResult) < 2 {
			return nil, fmt.Errorf("First method should return (model, error)")
		}

		// Check for error
		if err, ok := firstResult[1].Interface().(error); ok && err != nil {
			return nil, err
		}

		// Return model instance
		if model, ok := firstResult[0].Interface().(*T); ok {
			return model, nil
		}

		return nil, fmt.Errorf("failed to query model")
	}
}

// ModelLookup provides a unified interface for model parameter binding
// It follows the same pattern as other parameter binders like PathParam, QueryParam, etc.
// Usage: ModelLookup[models.User, int]("id", "id")
func ModelLookup[T any, K fiber.GenericType](field, pathKey string) func(fiber.Ctx) (*T, error) {
	return func(ctx fiber.Ctx) (*T, error) {
		// This is a placeholder implementation.
		// In the actual generated code, this function would be replaced with:
		// func(ctx fiber.Ctx) (*models.User, error) {
		//     v := fiber.Params[int](ctx, "id")
		//     return models.UserQuery.WithContext(ctx).Where(field.NewUnsafeFieldRaw("id = ?", v)).First()
		// }

		// The route generator should detect ModelLookup calls and generate the appropriate inline function
		return nil, fmt.Errorf("ModelLookup[%s] should be replaced by generated code for field '%s'", reflect.TypeOf((*T)(nil)).Elem().Name(), field)
	}
}

// ModelLegacy provides the original model binding interface for backward compatibility
func ModelLegacy[T any, K fiber.GenericType](modelName, field, pathKey string) func(fiber.Ctx) (*T, error) {
	return ModelLookup[T, K](field, pathKey)
}

// ModelQuery provides a more direct approach by accepting a query function
func ModelQuery[T any, K fiber.GenericType](queryFunc func(ctx fiber.Ctx, v K) (*T, error)) func(fiber.Ctx) (*T, error) {
	return func(ctx fiber.Ctx) (*T, error) {
		// Extract the parameter name from the query function or use a default
		// This is a limitation - we can't easily determine the path parameter name at runtime
		return nil, fmt.Errorf("ModelQuery requires path parameter name to be specified")
	}
}

// ModelQueryWithKey provides a complete implementation with specified path key
func ModelQueryWithKey[T any, K fiber.GenericType](queryFunc func(ctx fiber.Ctx, v K) (*T, error), pathKey string) func(fiber.Ctx) (*T, error) {
	return func(ctx fiber.Ctx) (*T, error) {
		v := fiber.Params[K](ctx, pathKey)
		return queryFunc(ctx, v)
	}
}

// ModelRegistry maintains model metadata for runtime reflection
type ModelRegistry struct {
	mu     sync.RWMutex
	models map[string]ModelInfo
}

// ModelInfo holds metadata about a model type
type ModelInfo struct {
	Type         reflect.Type
	QueryObject  interface{}
	DefaultField string
}

var registry = &ModelRegistry{
	models: make(map[string]ModelInfo),
}

// RegisterModel registers a model type with its query object
// This should be called during application initialization
func RegisterModel[T any](queryObject interface{}, defaultField string) {
	registry.mu.Lock()
	defer registry.mu.Unlock()

	var zero T
	modelType := reflect.TypeOf(zero)
	if modelType.Kind() == reflect.Ptr {
		modelType = modelType.Elem()
	}

	typeName := modelType.String()
	registry.models[typeName] = ModelInfo{
		Type:         modelType,
		QueryObject:  queryObject,
		DefaultField: defaultField,
	}
}

// Model provides a simplified model parameter binding interface without closures
// Usage: Model[models.User]("id") or Model[models.User]("role", "role")
func Model[T any](fieldAndPath ...string) func(fiber.Ctx) (*T, error) {
	var zero T
	modelType := reflect.TypeOf(zero)
	if modelType.Kind() == reflect.Ptr {
		modelType = modelType.Elem()
	}

	typeName := modelType.String()

	// Determine field and path key
	field := "id"
	pathKey := "id"

	switch len(fieldAndPath) {
	case 1:
		// Model[models.User]("role") - field=pathKey="role"
		field = fieldAndPath[0]
		pathKey = fieldAndPath[0]
	case 2:
		// Model[models.User]("user_id", "id") - field="user_id", pathKey="id"
		field = fieldAndPath[0]
		pathKey = fieldAndPath[1]
	}

	return func(ctx fiber.Ctx) (*T, error) {
		info, err := getModelInfo(typeName)
		if err != nil {
			return nil, err
		}

		// Extract path parameter
		paramValue := fiber.Params[string](ctx, pathKey)

		// Use reflection to call the query methods
		return executeModelQuery[T](info, field, paramValue, ctx)
	}
}

// ModelById provides an even simpler interface using the default id field
func ModelById[T any](pathKey string) func(fiber.Ctx) (*T, error) {
	return Model[T]("id", pathKey)
}

// getModelInfo retrieves model information from registry
func getModelInfo(typeName string) (*ModelInfo, error) {
	registry.mu.RLock()
	defer registry.mu.RUnlock()

	info, exists := registry.models[typeName]
	if !exists {
		return nil, fmt.Errorf("model %s not registered. Call RegisterModel[%s]() during initialization", typeName, typeName)
	}
	return &info, nil
}

// executeModelQuery performs the actual database query using reflection
func executeModelQuery[T any](info *ModelInfo, field, paramValue string, ctx fiber.Ctx) (*T, error) {
	queryValue := reflect.ValueOf(info.QueryObject)

	// Get WithContext method
	withContextMethod := queryValue.MethodByName("WithContext")
	if !withContextMethod.IsValid() {
		return nil, fmt.Errorf("query object does not have WithContext method")
	}

	// Call WithContext with the context
	contextResult := withContextMethod.Call([]reflect.Value{reflect.ValueOf(ctx)})
	if len(contextResult) == 0 {
		return nil, fmt.Errorf("WithContext method returned no result")
	}

	contextQuery := contextResult[0]

	// Get Where method
	whereMethod := contextQuery.MethodByName("Where")
	if !whereMethod.IsValid() {
		return nil, fmt.Errorf("query object does not have Where method")
	}

	// Get field object by field name from the original query object (not contextQuery)
	// If queryValue is a pointer, we need to get the element it points to
	var queryStruct reflect.Value
	if queryValue.Kind() == reflect.Ptr {
		queryStruct = queryValue.Elem()
	} else {
		queryStruct = queryValue
	}

	fieldValue := queryStruct.FieldByName(field)
	if !fieldValue.IsValid() {
		// Try with capitalized first letter for Go field naming convention
		capitalizedField := ""
		if len(field) > 0 {
			capitalizedField = strings.ToUpper(field[:1]) + field[1:]
		}
		fieldValue = queryStruct.FieldByName(capitalizedField)
		if !fieldValue.IsValid() {
			return nil, fmt.Errorf("query object does not have field '%s' or '%s'", field, capitalizedField)
		}
	}

	// Get Eq method from the field
	eqMethod := fieldValue.MethodByName("Eq")
	if !eqMethod.IsValid() {
		return nil, fmt.Errorf("field '%s' does not have Eq method", field)
	}

	// Convert paramValue to the appropriate type based on field type
	var paramValueReflect reflect.Value
	fieldType := fieldValue.Type()

	// Check if it's a field.String type
	if fieldType.String() == "field.String" {
		paramValueReflect = reflect.ValueOf(paramValue)
	} else if fieldType.String() == "field.Int32" || fieldType.String() == "field.Int" {
		var intVal int
		_, err := fmt.Sscanf(paramValue, "%d", &intVal)
		if err != nil {
			return nil, fmt.Errorf("failed to convert '%s' to int: %v", paramValue, err)
		}
		paramValueReflect = reflect.ValueOf(intVal)
	} else {
		// Fallback to basic kind-based detection
		switch fieldValue.Kind() {
		case reflect.String:
			paramValueReflect = reflect.ValueOf(paramValue)
		case reflect.Int, reflect.Int32:
			var intVal int
			_, err := fmt.Sscanf(paramValue, "%d", &intVal)
			if err != nil {
				return nil, fmt.Errorf("failed to convert '%s' to int: %v", paramValue, err)
			}
			paramValueReflect = reflect.ValueOf(intVal)
		default:
			return nil, fmt.Errorf("unsupported field type: %v (kind: %v)", fieldType, fieldValue.Kind())
		}
	}

	// Call Eq method to create condition
	conditionResult := eqMethod.Call([]reflect.Value{paramValueReflect})
	if len(conditionResult) == 0 {
		return nil, fmt.Errorf("Eq method returned no result")
	}

	// Call Where with the condition
	whereResult := whereMethod.Call([]reflect.Value{conditionResult[0]})
	if len(whereResult) == 0 {
		return nil, fmt.Errorf("Where method returned no result")
	}

	whereQuery := whereResult[0]

	// Get First method
	firstMethod := whereQuery.MethodByName("First")
	if !firstMethod.IsValid() {
		return nil, fmt.Errorf("query object does not have First method")
	}

	// Call First()
	firstResult := firstMethod.Call(nil)
	if len(firstResult) < 2 {
		return nil, fmt.Errorf("First method should return (model, error)")
	}

	// Check for error
	if err, ok := firstResult[1].Interface().(error); ok && err != nil {
		return nil, err
	}

	// Return model instance
	if model, ok := firstResult[0].Interface().(*T); ok {
		return model, nil
	}

	return nil, fmt.Errorf("failed to query model")
}