package glm

import (
	"fmt"
)

// Error represents a GLM SDK error
type Error struct {
	Code    string
	Message string
	Cause   error
}

// Error implements the error interface
func (e *Error) Error() string {
	if e.Cause != nil {
		return fmt.Sprintf("glm: %s: %s: %v", e.Code, e.Message, e.Cause)
	}
	return fmt.Sprintf("glm: %s: %s", e.Code, e.Message)
}

// Unwrap returns the underlying cause of the error
func (e *Error) Unwrap() error {
	return e.Cause
}

// NewError creates a new GLM error
func NewError(code, message string, cause error) *Error {
	return &Error{
		Code:    code,
		Message: message,
		Cause:   cause,
	}
}

// Error codes
const (
	ErrCodeInvalidConfig       = "INVALID_CONFIG"
	ErrCodeHTTPError          = "HTTP_ERROR"
	ErrCodeInvalidRequest     = "INVALID_REQUEST"
	ErrCodeAuthentication     = "AUTHENTICATION_ERROR"
	ErrCodeRateLimit         = "RATE_LIMIT_ERROR"
	ErrCodeServerError       = "SERVER_ERROR"
	ErrCodeInvalidResponse   = "INVALID_RESPONSE"
	ErrCodeChatCompletion    = "CHAT_COMPLETION_ERROR"
	ErrCodeModelNotFound     = "MODEL_NOT_FOUND"
	ErrCodeTokenLimit        = "TOKEN_LIMIT_ERROR"
	ErrCodeStreamError       = "STREAM_ERROR"
)

// Error constructors
func ErrInvalidConfig(message string) *Error {
	return NewError(ErrCodeInvalidConfig, message, nil)
}

func ErrHTTPError(statusCode int, message string) *Error {
	return NewError(ErrCodeHTTPError, fmt.Sprintf("HTTP %d: %s", statusCode, message), nil)
}

func ErrInvalidRequest(message string) *Error {
	return NewError(ErrCodeInvalidRequest, message, nil)
}

func ErrAuthentication(message string) *Error {
	return NewError(ErrCodeAuthentication, message, nil)
}

func ErrRateLimit(message string) *Error {
	return NewError(ErrCodeRateLimit, message, nil)
}

func ErrServerError(message string) *Error {
	return NewError(ErrCodeServerError, message, nil)
}

func ErrInvalidResponse(message string) *Error {
	return NewError(ErrCodeInvalidResponse, message, nil)
}

func ErrChatCompletion(message string, cause error) *Error {
	return NewError(ErrCodeChatCompletion, message, cause)
}

func ErrModelNotFound(model string) *Error {
	return NewError(ErrCodeModelNotFound, fmt.Sprintf("model '%s' not found", model), nil)
}

func ErrTokenLimit(message string) *Error {
	return NewError(ErrCodeTokenLimit, message, nil)
}

func ErrStreamError(message string, cause error) *Error {
	return NewError(ErrCodeStreamError, message, cause)
}