package twitch

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"path"
	"strings"

	"codeberg.org/arimelody/ari-stream-tools/twitch/api"
)

func (srv *Service) userIDsFromNames(usernames []string) ([]string, error) {
	if len(usernames) == 0 { return []string{}, nil }

	url := strings.Builder{}
	url.WriteString(api.BASE_URL)
	url.WriteString("/users?login=")
	url.WriteString(usernames[0])
	for _, username := range usernames {
		url.WriteString("&login=")
		url.WriteString(username)
	}

	req, err := http.NewRequest("GET", url.String(), nil)
	if err != nil { return nil, err }

	req.Header.Set("Client-Id", srv.clientID)
	req.Header.Set("Authorization", "Bearer " + srv.oauthToken.AccessToken)

	res, err := http.DefaultClient.Do(req)
	if err != nil { return nil, err }

	if res.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(res.Body)
		return nil, fmt.Errorf("%s: %s", res.Status, string(body))
	}

	type (
		UserData struct {
			ID string `json:"id"`
			Login string `json:"login"`
			DisplayName string `json:"display_name"`
			Type string `json:"type"`
			BroadcasterType string `json:"broadcaster_type"`
			Description string `json:"description"`
			ProfileImageURL string `json:"profile_image_url"`
			OfflineImageURL string `json:"offline_image_url"`
			ViewCount int `json:"view_count"`
			Email string `json:"email"`
			CreatedAt string `json:"created_at"`
		}

		Response struct {
			Users []UserData `json:"data"`
		}
	)
	data := Response{}
	if err := json.NewDecoder(res.Body).Decode(&data); err != nil {
		return nil, err
	}

	userIDs := []string{}
	for _, user := range data.Users {
		userIDs = append(userIDs, user.ID)
	}

	return userIDs, nil
}

func (srv *Service) registerEventSubSession(session *api.EventSubSession) error {
	srv.eventSubSession = session
	return nil
}

func (srv *Service) handleNotification(payload *api.EventSubPayload) error {
	var err error
	jsonData, err := json.Marshal(payload.Event)
	if err != nil { return err }

	switch payload.Subscription.Type {

	case "channel.follow":
		var event api.FollowEvent
		err := json.Unmarshal(jsonData, &event)
		if err != nil { return fmt.Errorf("Failed to cast to api.FollowEvent: %v", err) }
		log.Printf("New follow: %s", event.UserLogin)
		srv.labels.LatestFollower.Text = event.UserLogin
		srv.labels.LatestFollower.C <- event.UserLogin

		if err := os.WriteFile(
			path.Join(DATA_PATH, "state", LABEL_LATEST_FOLLOWER),
			[]byte(event.UserLogin), 0640,
		); err != nil {
			return fmt.Errorf("Failed to write %s state: %v", LABEL_LATEST_FOLLOWER, err)
		}

	case "channel.subscribe":
		var event api.SubscribeEvent
		err := json.Unmarshal(jsonData, &event)
		if err != nil { return fmt.Errorf("Failed to cast to api.SubscribeEvent: %v", err) }
		log.Printf("New subscription: %s", event.UserLogin)
		srv.labels.LatestSubscriber.Text = event.UserLogin
		srv.labels.LatestSubscriber.C <- event.UserLogin

		if err := os.WriteFile(
			path.Join(DATA_PATH, "state", LABEL_LATEST_SUBSCRIBER),
			[]byte(event.UserLogin), 0640,
		); err != nil {
			return fmt.Errorf("Failed to write %s state: %v", LABEL_LATEST_SUBSCRIBER, err)
		}

	case "channel.cheer":
		var event api.CheerEvent
		err := json.Unmarshal(jsonData, &event)
		if err != nil { return fmt.Errorf("Failed to cast to api.CheerEvent: %v", err) }
		log.Printf("%s cheered x%d bits: %s", event.UserLogin, event.Bits, event.Message)
		srv.labels.LatestCheer.Text = event.UserLogin
		srv.labels.LatestCheer.C <- event.UserLogin

		if err := os.WriteFile(
			path.Join(DATA_PATH, "state", LABEL_LATEST_CHEER),
			[]byte(event.UserLogin), 0640,
		); err != nil {
			return fmt.Errorf("Failed to write %s state: %v", LABEL_LATEST_CHEER, err)
		}

	case "channel.raid":
		var event api.RaidEvent
		err := json.Unmarshal(jsonData, &event)
		if err != nil { return fmt.Errorf("Failed to cast to api.RaidEvent: %v", err) }
		log.Printf("%s is now raiding with %d viewers!", event.FromUserLogin, event.Viewers)

	case "channel.channel_points_custom_reward_redemption.add":
		var event api.ChannelPointCustomRewardRedeemEvent
		err := json.Unmarshal(jsonData, &event)
		if err != nil { return fmt.Errorf("Failed to cast to api.ChannelPointCustomRewardRedeemEvent: %v", err) }
		log.Printf(
			"%s just redeemed %s for %d channel points.",
			event.UserLogin,
			event.Reward.Title,
			event.Reward.Cost,
		)

	case "channel.shoutout.create":
		var event api.ShoutoutCreate
		err := json.Unmarshal(jsonData, &event)
		if err != nil { return fmt.Errorf("Failed to cast to api.ShoutoutCreate: %v", err) }
		log.Printf(
			"%s gave a shoutout to %s.",
			event.FromUserLogin,
			event.ToUserLogin,
		)

	case "channel.chat.message":
		var event api.ChatEvent
		err := json.Unmarshal(jsonData, &event)
		if err != nil { return fmt.Errorf("Failed to cast to api.ChatEvent: %v", err) }
		if event.Cheer != nil { return nil }
		log.Printf(
			"[%s] %s: %s",
			event.MessageID,
			event.ChatterLogin,
			event.Message.Text,
		)

	case "channel.chat.message_delete":
		var event api.ChatDeleteEvent
		err := json.Unmarshal(jsonData, &event)
		if err != nil { return fmt.Errorf("Failed to cast to api.ChatDeleteEvent: %v", err) }
		log.Printf(
			"Message %s by %s deleted.",
			event.MessageID,
			event.TargetLogin,
		)

	}

	return nil
}

func (srv *Service) subscribeToEvent(
	ctx context.Context,
	subscriptionType string,
	version string,
	condition map[string]string,
	sessionID string,
) error {
	type (
		Transport struct {
			Method string `json:"method"`
			SessionID string `json:"session_id"`
		}

		Request struct {
			Type string `json:"type"`
			Version string `json:"version"`
			Condition map[string]string `json:"condition"`
			Transport Transport `json:"transport"`
		}

		ResponseData struct {
			ID string `json:"id"`
			Status string `json:"status"`
			Type string `json:"type"`
			Version string `json:"version"`
			Condition map[string]string `json:"condition"`
			CreatedAt string `json:"created_at"`
			Transport Transport `json:"transport"`
			Cost int `json:"cost"`
		}
		Response struct {
			Data []ResponseData `json:"data"`
			Total int `json:"total"`
			TotalCost int `json:"total_cost"`
			MaxTotalCost int `json:"max_total_cost"`
		}
	)

	bodyBytes, err := json.Marshal(Request{
		Type: subscriptionType,
		Version: version,
		Condition: condition,
		Transport: Transport{
			Method: "websocket",
			SessionID: sessionID,
		},
	})
	body := bytes.NewBuffer(bodyBytes)

	client := srv.oauthConfig.Client(ctx, srv.oauthToken)
	req, err := http.NewRequest(
		"POST",
		api.BASE_URL + "/eventsub/subscriptions",
		body,
	)
	if err != nil { return err }

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Client-Id", srv.clientID)
	req.Header.Set("Authorization", "Bearer " + srv.oauthToken.AccessToken)

	res, err := client.Do(req)
	if err != nil { return err }

	if res.StatusCode != http.StatusAccepted {
		body, _ := io.ReadAll(res.Body)
		return fmt.Errorf("%s: %s", res.Status, string(body))
	}

	return nil
}

func (srv *Service) subscribeToDefaultEvents(ctx context.Context) {
	// channel.follow
	if err := srv.subscribeToEvent(
		ctx, "channel.follow", "2",
		map[string]string{
			"broadcaster_user_id": srv.channelID,
			"moderator_user_id": srv.channelID,
		},
		srv.eventSubSession.ID,
	); err != nil {
		log.Printf("Failed to subscribe to channel.follow: %v", err)
	}

	// channel.subscribe
	if err := srv.subscribeToEvent(
		ctx, "channel.subscribe", "1",
		map[string]string{ "broadcaster_user_id": srv.channelID },
		srv.eventSubSession.ID,
	); err != nil {
		log.Printf("Failed to subscribe to channel.subscribe: %v", err)
	}

	// channel.cheer
	if err := srv.subscribeToEvent(
		ctx, "channel.cheer", "1",
		map[string]string{ "broadcaster_user_id": srv.channelID },
		srv.eventSubSession.ID,
	); err != nil {
		log.Printf("Failed to subscribe to channel.cheer: %v", err)
	}

	// channel.raid
	if err := srv.subscribeToEvent(
		ctx, "channel.raid", "1",
		map[string]string{ "to_broadcaster_user_id": srv.channelID },
		srv.eventSubSession.ID,
	); err != nil {
		log.Printf("Failed to subscribe to channel.raid: %v", err)
	}

	// channel.channel_points_custom_reward_redemption.add
	if err := srv.subscribeToEvent(
		ctx, "channel.channel_points_custom_reward_redemption.add", "1",
		map[string]string{ "broadcaster_user_id": srv.channelID },
		srv.eventSubSession.ID,
	); err != nil {
		log.Printf("Failed to subscribe to channel.channel_points_custom_reward_redemption.add: %v", err)
	}

	// channel.shoutout.create
	if err := srv.subscribeToEvent(
		ctx, "channel.shoutout.create", "1",
		map[string]string{
			"broadcaster_user_id": srv.channelID,
			"moderator_user_id": srv.channelID,
		},
		srv.eventSubSession.ID,
	); err != nil {
		log.Printf("Failed to subscribe to channel.shoutout.create: %v", err)
	}

	// channel.chat.message
	if err := srv.subscribeToEvent(
		ctx, "channel.chat.message", "1",
		map[string]string{
			"broadcaster_user_id": srv.channelID,
			"user_id": srv.channelID,
		},
		srv.eventSubSession.ID,
	); err != nil {
		log.Printf("Failed to subscribe to channel.chat.message: %v", err)
	}

	// channel.chat.message_delete
	if err := srv.subscribeToEvent(
		ctx, "channel.chat.message_delete", "1",
		map[string]string{
			"broadcaster_user_id": srv.channelID,
			"user_id": srv.channelID,
		},
		srv.eventSubSession.ID,
	); err != nil {
		log.Printf("Failed to subscribe to channel.chat.message_delete: %v", err)
	}
}