package main

import (
	"context"
	"encoding/json"
	"errors"
	"io"
	"log/slog"
	"net/http"
	"platform/pkg/env"
	"platform/pkg/logs"
	"platform/pkg/rds"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/redis/go-redis/v9"
)

var RemoveEndpoint = "http://localhost:8080/api/channel/remove"

func main() {
	Start()
}

var taskList = make(map[string]func(ctx context.Context, curr time.Time) error)

func Start() {
	ctx := context.Background()

	env.Init()
	logs.Init()
	rds.Init()

	taskList["stopChannels"] = stopChannels

	ticker := time.NewTicker(30 * time.Second)
	defer ticker.Stop()

	// 互斥锁确保同一时间只有一个协程运行
	// 如果之前的 tick 操作未完成，则跳过当前 tick
	var mutex = &sync.Mutex{}
	for curr := range ticker.C {
		if mutex.TryLock() {
			err := process(ctx, curr)
			if err != nil {
				panic(err)
			}
			mutex.Unlock()
		} else {
			slog.Warn("skip tick", slog.String("tick", curr.Format("2006-01-02 15:04:05")))
		}
	}
}

func process(ctx context.Context, curr time.Time) error {

	// todo 异步化
	for name, task := range taskList {
		err := task(ctx, curr)
		if err != nil {
			slog.Error("task failed", slog.String("task", name), slog.String("error", err.Error()))
		}
	}

	return nil
}

func stopChannels(ctx context.Context, curr time.Time) error {

	// 查询过期的 channel
	result, err := rds.Client.ZRangeByScore(ctx, "tasks:channel", &redis.ZRangeBy{
		Min: "0",
		Max: strconv.FormatInt(curr.Unix(), 10),
	}).Result()
	if err != nil {
		return err
	}
	if len(result) == 0 {
		return nil
	}

	ids := make([]int32, len(result))
	for i, str := range result {
		id, err := strconv.ParseInt(str, 10, 32)
		if err != nil {
			return err
		}
		ids[i] = int32(id)
	}

	// 删除过期的 channel
	body, err := json.Marshal(map[string]any{
		"by_ids": ids,
	})
	if err != nil {
		return err
	}
	req, err := http.NewRequest(
		http.MethodPost,
		RemoveEndpoint,
		strings.NewReader(string(body)),
	)
	if err != nil {
		return err
	}
	req.Header.Set("Content-Type", "application/json")
	req.SetBasicAuth("tasks", "tasks")

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			return err
		}
		return errors.New("failed to stop channels: " + string(body))
	}

	// 删除 redis 中的 channel
	_, err = rds.Client.ZRemRangeByScore(ctx, "tasks:channel", "0", strconv.FormatInt(curr.Unix(), 10)).Result()

	return nil
}