package main

import (
	"fmt"
	"strconv"
	"strings"
	"time"

	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm"
	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm/types"
	"github.com/tidwall/gjson"
	"github.com/tidwall/resp"

	"github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
)

func main() {
	wrapper.SetCtx(
		"redis-demo",
		wrapper.ParseConfigBy(parseConfig),
		wrapper.ProcessRequestHeadersBy(onHttpRequestHeaders),
		wrapper.ProcessResponseHeadersBy(onHttpResponseHeaders),
	)
}

type RedisCallConfig struct {
	client wrapper.RedisClient
	qpm    int
}

func parseConfig(json gjson.Result, config *RedisCallConfig, log wrapper.Log) error {
	// 带服务类型的完整 FQDN 名称，例如 my-redis.dns、redis.my-ns.svc.cluster.local
	serviceName := json.Get("serviceName").String()
	servicePort := json.Get("servicePort").Int()
	if servicePort == 0 {
		if strings.HasSuffix(serviceName, ".static") {
			// 静态IP类型服务的逻辑端口是80
			servicePort = 80
		} else {
			servicePort = 6379
		}
	}
	username := json.Get("username").String()
	password := json.Get("password").String()
	// 单位是毫秒
	timeout := json.Get("timeout").Int()
	if timeout == 0 {
		timeout = 1000
	}
	qpm := json.Get("qpm").Int()
	config.qpm = int(qpm)
	config.client = wrapper.NewRedisClusterClient(wrapper.FQDNCluster{
		FQDN: serviceName,
		Port: servicePort,
	})
	err := config.client.Init(username, password, timeout)
	if err != nil {
		log.Errorf("init redis client failed")
	} else {
		log.Error("init redis client success")
		err := config.client.Set("name", "pax", func(response resp.Value) {
			if response.Error() != nil {
				log.Errorf("redis client set failed")
			} else {
				log.Errorf("print redis client set reponse " + response.String())
			}
		})
		if err != nil {
			log.Errorf("redis client set failed")
		} else {
			log.Errorf("redis client set success")
			config.client.Get("name", func(response resp.Value) {
				if response.Error() != nil {
					log.Errorf("redis client get failed")
				} else {
					log.Errorf("print redis client get reponse " + response.String())
				}
			})
		}
		log.Error("init redis client success")
	}
	return err
}

func onHttpRequestHeaders(ctx wrapper.HttpContext, config RedisCallConfig, log wrapper.Log) types.Action {
	now := time.Now()
	minuteAligned := now.Truncate(time.Minute)
	timeStamp := strconv.FormatInt(minuteAligned.Unix(), 10)
	// 如果 redis api 返回的 err != nil，一般是由于网关找不到 redis 后端服务，请检查是否误删除了 redis 后端服务
	err := config.client.Incr(timeStamp, func(response resp.Value) {
		if response.Error() != nil {
			fmt.Println(response.Error())
			log.Errorf("call redis error: %v", response.Error())
			proxywasm.ResumeHttpRequest()
		} else {
			log.Errorf("start redis on http request headers")
			ctx.SetContext("timeStamp", timeStamp)
			ctx.SetContext("callTimeLeft", strconv.Itoa(config.qpm-response.Integer()))
			if response.Integer() == 1 {
				err := config.client.Expire(timeStamp, 60, func(response resp.Value) {
					if response.Error() != nil {
						log.Errorf("call redis error: %v", response.Error())
					}
					proxywasm.ResumeHttpRequest()
				})
				if err != nil {
					fmt.Println(err.Error())
					log.Errorf(err.Error())
					log.Errorf("Error occured while calling redis, it seems cannot find the redis cluster.")
					proxywasm.ResumeHttpRequest()
				}
			} else {
				if response.Integer() > config.qpm {
					proxywasm.SendHttpResponse(429, [][2]string{{"timeStamp", timeStamp}, {"callTimeLeft", "0"}}, []byte("Too many requests\n"), -1)
				} else {
					proxywasm.ResumeHttpRequest()
				}
			}
		}
	})
	if err != nil {
		fmt.Println(err.Error())
		log.Errorf(err.Error())
		// 由于调用redis失败，放行请求，记录日志
		log.Errorf("Error occured while calling redis, it seems cannot find the redis cluster.")
		return types.ActionContinue
	} else {
		// 请求hold住，等待redis调用完成
		return types.ActionPause
	}
}

func onHttpResponseHeaders(ctx wrapper.HttpContext, config RedisCallConfig, log wrapper.Log) types.Action {
	if ctx.GetContext("timeStamp") != nil {
		proxywasm.AddHttpResponseHeader("timeStamp", ctx.GetContext("timeStamp").(string))
	}
	if ctx.GetContext("callTimeLeft") != nil {
		proxywasm.AddHttpResponseHeader("callTimeLeft", ctx.GetContext("callTimeLeft").(string))
	}
	return types.ActionContinue
}