package workflows

import (
	"context"
	"golang-lab4/models"
	"golang-lab4/utils"
	"time"

	"github.com/go-resty/resty/v2"
	"github.com/spf13/viper"
	"github.com/uptrace/bun"
	"go.uber.org/zap"
)

const (
	REFETCH_TICK = 5 * time.Second
)

type Fetcher struct {
	db     *bun.DB
	client *resty.Client
	urls   map[string]struct{}
	doneCh chan string
}

func NewFetcher(db *bun.DB) *Fetcher {
	urlSlice, err := utils.LoadUrls(viper.GetString("savefile"))
	if err != nil {
		panic(err)
	}

	urls := make(map[string]struct{})
	for _, url := range urlSlice {
		urls[url] = struct{}{}
	}

	return &Fetcher{
		db:     db,
		client: resty.New(),
		urls:   urls,
		doneCh: make(chan string),
	}
}

func (self *Fetcher) fetch(url string) models.UrlState {
	before := time.Now()
	zap.L().Info("fetch",
		zap.String("url", url))
	resp, err := self.client.R().
		Get(url)

	return models.UrlState{
		Url:       url,
		IsSuccess: (err == nil && resp.IsSuccess()),
		Latency:   uint(time.Now().Sub(before) / time.Millisecond),
	}
}

func (self *Fetcher) fetchAndSleep(url string) {
	res := self.fetch(url)

	time.Sleep(REFETCH_TICK)

	_, err := self.db.NewInsert().
		Model(&res).
		On("CONFLICT (url) DO UPDATE").
		Set("is_success = ?", res.IsSuccess).
		Set("latency = ?", res.Latency).
		Exec(context.Background())
	if err != nil {
		panic(err)
	}
	self.doneCh <- url
}

func (self *Fetcher) SyncFile() {
	urlSlice := []string{}
	for url := range self.urls {
		urlSlice = append(urlSlice, url)
	}

	err := utils.SaveUrls(viper.GetString("savefile"), urlSlice)
	if err != nil {
		panic(err)
	}
}

func (self *Fetcher) Add(url string) {
	self.urls[url] = struct{}{}
	self.SyncFile()
	go self.fetchAndSleep(url)
}

func (self *Fetcher) Remove(url string) {
	delete(self.urls, url)
	self.SyncFile()
	self.db.NewDelete().
		Model((*models.UrlState)(nil)).
		Where("url = ?", url).
		Exec(context.Background())
}

func (self *Fetcher) Run() {
	for url := range self.urls {
		go self.fetchAndSleep(url)
	}

	for {
		url := <-self.doneCh
		if _, ok := self.urls[url]; ok {
			go self.fetchAndSleep(url)
		}
	}
}