package runtime

import (
	"fmt"
	"net/http"
	"runtime"
	"sorbet/internal/util"
	"sorbet/pkg/log"

	"github.com/labstack/echo/v4"
)

// LogErrorFunc defines a function for custom logging in the middleware.
type LogErrorFunc func(c echo.Context, err error, stack []byte) error

// RecoverConfig defines the config for Recover middleware.
type RecoverConfig struct {
	// Size of the stack to be printed.
	// Optional. Default value 4KB.
	StackSize int

	// DisableStackAll disables formatting stack traces of all other goroutines
	// into buffer after the trace for the current goroutine.
	// Optional. Default value false.
	DisableStackAll bool

	// DisablePrintStack disables printing stack trace.
	// Optional. Default value as false.
	DisablePrintStack bool

	// LogLevel is log level to printing stack trace.
	// Optional. Default value 0 (Print).
	LogLevel log.Level

	// LogErrorFunc defines a function for custom logging in the middleware.
	// If it's set you don't need to provide LogLevel for config.
	// If this function returns nil, the centralized HTTPErrorHandler will not be called.
	LogErrorFunc LogErrorFunc

	// DisableErrorHandler disables the call to centralized HTTPErrorHandler.
	// The recovered error is then passed back to upstream middleware, instead of swallowing the error.
	// Optional. Default value false.
	DisableErrorHandler bool
}

// DefaultRecoverConfig is the default Recover middleware config.
var DefaultRecoverConfig = RecoverConfig{
	StackSize:           4 << 10, // 4 KB
	DisableStackAll:     false,
	DisablePrintStack:   false,
	LogLevel:            log.LevelDebug,
	LogErrorFunc:        nil,
	DisableErrorHandler: false,
}

// Recover returns a middleware which recovers from panics anywhere in the chain
// and handles the control to the centralized HTTPErrorHandler.
func Recover(next echo.HandlerFunc) echo.HandlerFunc {
	return RecoverWithConfig(DefaultRecoverConfig)(next)
}

func RecoverWithConfig(config RecoverConfig) echo.MiddlewareFunc {
	if config.StackSize == 0 {
		config.StackSize = DefaultRecoverConfig.StackSize
	}
	switch config.LogLevel {
	case log.LevelTrace, log.LevelFatal, log.LevelPanic:
		panic("不应该将 LevelTrace、LevelFatal 和 LevelPanic 这三个日志作用在错误恢复中间件上")
	}
	return func(next echo.HandlerFunc) echo.HandlerFunc {
		return func(c echo.Context) (returnErr error) {
			defer func() {
				if r := recover(); r != nil {
					if r == http.ErrAbortHandler {
						panic(r)
					}
					err, ok := r.(error)
					if !ok {
						err = fmt.Errorf("%v", r)
					}
					var stack []byte
					var length int
					if !config.DisablePrintStack {
						stack = make([]byte, config.StackSize)
						length = runtime.Stack(stack, !config.DisableStackAll)
						stack = stack[:length]
					}
					if config.LogErrorFunc != nil {
						err = config.LogErrorFunc(c, err, stack)
					} else if !config.DisablePrintStack {
						var i []any
						if _, ok := c.Logger().(*util.EchoLogger); ok {
							i = append(i,
								fmt.Sprintf("%v %s\n", err, stack[:length]),
								log.RawLevel("PANIC RECOVER"),
							)
						} else {
							i = append(i, fmt.Sprintf("[PANIC RECOVER] %v %s\n", err, stack[:length]))
						}
						switch config.LogLevel {
						case log.LevelDebug:
							c.Logger().Debug(i...)
						case log.LevelInfo:
							c.Logger().Info(i...)
						case log.LevelWarn:
							c.Logger().Warn(i...)
						case log.LevelError:
							c.Logger().Error(i...)
						case log.LevelOff:
							// None.
						default:
							c.Logger().Print(i...)
						}
					}
					if err != nil && !config.DisableErrorHandler {
						c.Error(err)
					} else {
						returnErr = err
					}
				}
			}()
			return next(c)
		}
	}
}