// Package api provides error handling utilities for the API
package api

import (
	"encoding/json"
	"net/http"
	"time"
)

// ErrorResponse represents a standardized error response
type ErrorResponse struct {
	Error     bool      `json:"error"`
	Code      byte      `json:"code"`
	Message   string    `json:"message"`
	Details   string    `json:"details,omitempty"`
	Timestamp time.Time `json:"timestamp"`
	RequestID string    `json:"request_id,omitempty"`
}

// SuccessResponse represents a standardized success response
type SuccessResponse struct {
	Success   bool        `json:"success"`
	Data      interface{} `json:"data,omitempty"`
	Timestamp time.Time   `json:"timestamp"`
}

// WriteError writes a standardized error response
func WriteError(w http.ResponseWriter, code byte, message, details string, statusCode int) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(statusCode)

	response := ErrorResponse{
		Error:     true,
		Code:      code,
		Message:   message,
		Details:   details,
		Timestamp: time.Now().UTC(),
	}

	json.NewEncoder(w).Encode(response)
}

// WriteSuccess writes a standardized success response
func WriteSuccess(w http.ResponseWriter, data interface{}) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)

	response := SuccessResponse{
		Success:   true,
		Data:      data,
		Timestamp: time.Now().UTC(),
	}

	json.NewEncoder(w).Encode(response)
}

// Common error codes for API responses
const (
	ErrCodeUnknownError          = 0x00
	ErrCodeInvalidRequest        = 0x01
	ErrCodeAuthenticationFailed  = 0x02
	ErrCodePermissionDenied      = 0x03
	ErrCodeResourceNotFound      = 0x04
	ErrCodeResourceAlreadyExists = 0x05
	ErrCodeServerOverloaded      = 0x10
	ErrCodeDatabaseError         = 0x11
	ErrCodeNetworkError          = 0x12
	ErrCodeStorageError          = 0x13
	ErrCodeTimeout               = 0x14
	ErrCodeJobNotFound           = 0x20
	ErrCodeJobAlreadyRunning     = 0x21
	ErrCodeJobFailedToStart      = 0x22
	ErrCodeJobExecutionFailed    = 0x23
	ErrCodeJobCancelled          = 0x24
	ErrCodeOutOfMemory           = 0x30
	ErrCodeDiskFull              = 0x31
	ErrCodeInvalidConfiguration  = 0x32
	ErrCodeServiceUnavailable    = 0x33
)

// HTTP status code mappings
const (
	StatusBadRequest           = http.StatusBadRequest
	StatusUnauthorized         = http.StatusUnauthorized
	StatusForbidden            = http.StatusForbidden
	StatusNotFound             = http.StatusNotFound
	StatusConflict             = http.StatusConflict
	StatusInternalServerError  = http.StatusInternalServerError
	StatusServiceUnavailable   = http.StatusServiceUnavailable
	StatusTooManyRequests      = http.StatusTooManyRequests
)

// ErrorCodeToHTTPStatus maps API error codes to HTTP status codes
func ErrorCodeToHTTPStatus(code byte) int {
	switch code {
	case ErrCodeInvalidRequest:
		return StatusBadRequest
	case ErrCodeAuthenticationFailed:
		return StatusUnauthorized
	case ErrCodePermissionDenied:
		return StatusForbidden
	case ErrCodeResourceNotFound, ErrCodeJobNotFound:
		return StatusNotFound
	case ErrCodeResourceAlreadyExists, ErrCodeJobAlreadyRunning:
		return StatusConflict
	case ErrCodeServerOverloaded, ErrCodeServiceUnavailable:
		return StatusServiceUnavailable
	case ErrCodeDatabaseError, ErrCodeNetworkError, ErrCodeStorageError:
		return StatusInternalServerError
	default:
		return StatusInternalServerError
	}
}

// NewErrorResponse creates a new error response with the given details
func NewErrorResponse(code byte, message, details string) ErrorResponse {
	return ErrorResponse{
		Error:     true,
		Code:      code,
		Message:   message,
		Details:   details,
		Timestamp: time.Now().UTC(),
	}
}

// NewSuccessResponse creates a new success response with the given data
func NewSuccessResponse(data interface{}) SuccessResponse {
	return SuccessResponse{
		Success:   true,
		Data:      data,
		Timestamp: time.Now().UTC(),
	}
}