package history

import (
	"encoding/json"
	"fmt"
	"sync"
	"time"

	"gorm.io/gorm"
	"kumoly.io/kumoly/app/errors"
	"kumoly.io/kumoly/app/store"
)

const (
	ERROR = "ERROR"
	INFO  = "INFO"
)

type History struct {
	ID       uint `gorm:"primaryKey"`
	Module   string
	Type     string
	Caller   string
	Trace    string
	BodyJson string

	Name    string
	Message string
	Body    interface{} `gorm:"-"`
	Issuer  string
	// Group to identify auth, empty for admin
	Group string
	// Scope for users to narrow down view point
	Scope string

	CreatedAt time.Time
}

func (h *History) BeforeCreate(tx *gorm.DB) (err error) {
	if h.Body != nil {
		if body, err := json.Marshal(h.Body); err != nil {
			l.Error().Str("mod", "history").Err(err).Msg("history create error")
		} else {
			h.BodyJson = string(body)
		}
	}
	return
}

var Tunnel chan *History
var quit chan struct{}
var started chan struct{}
var wg sync.WaitGroup

func init() {
	Tunnel = make(chan *History)
	quit = make(chan struct{}, 1)
	started = make(chan struct{}, 1)
}

func Start(r Receiver) {
	if len(started) == 1 {
		panic(errors.New(500, "history reporter has already started!"))
	}
	started <- struct{}{}
	go func() {
		for {
			select {
			case h := <-Tunnel:
				wg.Add(1)
				if Interceptor != nil {
					Interceptor(h)
				}
				r(h)
				wg.Done()
			case <-quit:
				<-started
				return
			}
		}
	}()
}

func Stop() {
	if len(started) == 0 {
		return
	}
	quit <- struct{}{}
	l.Debug().Str("mod", "history").Msg("stop received")
	wg.Wait()
	l.Debug().Str("mod", "history").Msg("stopped")
}

func Send(h *History) {
	if len(started) == 0 {
		l.Warn().Str("mod", "history").
			Interface("history", h).
			Msg("history reporter has not started, report will be discarded")
		return
	}
	if h.Type == "" {
		h.Type = INFO
	}
	Tunnel <- h
}

type Receiver func(*History)

var Interceptor func(*History) = nil

var DBReceiver Receiver = func(h *History) {
	err := store.DB.Create(h).Error
	if err != nil {
		l.Error().Str("mod", "history").
			Interface("history", h).
			Err(err).Msg("DBReceiver error")
	}
}

var ConsoleReceiver Receiver = func(h *History) {
	fmt.Printf("%+v\n", h)
}