package controller

import (
	"bufio"
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"net/http"
	"one-api/common"
	"one-api/model"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/gin-gonic/gin"
)

func testChannel(channel *model.Channel, request ChatRequest) error {
	switch channel.Type {
	case common.ChannelTypeAzure:
		request.Model = "gpt-35-turbo"
	default:
		request.Model = "gpt-3.5-turbo"
	}
	requestURL := common.ChannelBaseURLs[channel.Type]
	if channel.Type == common.ChannelTypeAzure {
		requestURL = fmt.Sprintf("%s/openai/deployments/%s/chat/completions?api-version=2023-03-15-preview", channel.BaseURL, request.Model)
	} else {
		if channel.BaseURL != "" {
			requestURL = channel.BaseURL
		}
		requestURL += "/v1/chat/completions"
	}

	jsonData, err := json.Marshal(request)
	if err != nil {
		return err
	}
	req, err := http.NewRequest("POST", requestURL, bytes.NewBuffer(jsonData))
	if err != nil {
		return err
	}
	if channel.Type == common.ChannelTypeAzure {
		req.Header.Set("api-key", channel.Key)
	} else {
		req.Header.Set("Authorization", "Bearer "+channel.Key)
	}
	req.Header.Set("Content-Type", "application/json")
	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		return err
	}

	var response TextResponse
	isStream := strings.HasPrefix(resp.Header.Get("Content-Type"), "text/event-stream")
	var streamResponseText string

	if isStream {
		scanner := bufio.NewScanner(resp.Body)
		scanner.Split(func(data []byte, atEOF bool) (advance int, token []byte, err error) {
			if atEOF && len(data) == 0 {
				return 0, nil, nil
			}

			if i := strings.Index(string(data), "\n\n"); i >= 0 {
				return i + 2, data[0:i], nil
			}

			if atEOF {
				return len(data), data, nil
			}

			return 0, nil, nil
		})
		for scanner.Scan() {
			data := scanner.Text()
			if len(data) < 6 { // must be something wrong!
				common.SysError("invalid stream response: " + data)
				continue
			}
			data = data[6:]
			if !strings.HasPrefix(data, "[DONE]") {
				var streamResponse ChatCompletionsStreamResponse
				err = json.Unmarshal([]byte(data), &streamResponse)
				if err != nil {
					common.SysError("error unmarshalling stream response: " + err.Error())
					return err
				}
				for _, choice := range streamResponse.Choices {
					streamResponseText += choice.Delta.Content
				}
			}
		}

		if streamResponseText == "" {
			return errors.New("empty stream response")
		}
	} else {
		body, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			return err
		}
		err = json.Unmarshal(body, &response)
		if err != nil {
			return err
		}

		// channel.BaseURL starts with https://api.openai.com
		if response.Usage.CompletionTokens == 0 && strings.HasPrefix(channel.BaseURL, "https://api.openai.com") {
			return errors.New(fmt.Sprintf("type %s, code %v, message %s", response.Error.Type, response.Error.Code, response.Error.Message))
		}
	}

	defer resp.Body.Close()

	return nil
}

func buildTestRequest() *ChatRequest {
	testRequest := &ChatRequest{
		Model:     "", // this will be set later
		MaxTokens: 1,
	}
	testMessage := Message{
		Role:    "user",
		Content: "hi",
	}
	testRequest.Messages = append(testRequest.Messages, testMessage)
	return testRequest
}

func TestChannel(c *gin.Context) {
	id, err := strconv.Atoi(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	channel, err := model.GetChannelById(id, true)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	testRequest := buildTestRequest()
	tik := time.Now()
	err = testChannel(channel, *testRequest)
	tok := time.Now()
	milliseconds := tok.Sub(tik).Milliseconds()
	go channel.UpdateResponseTime(milliseconds)
	consumedTime := float64(milliseconds) / 1000.0
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
			"time":    consumedTime,
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
		"time":    consumedTime,
	})
	return
}

var testAllChannelsLock sync.Mutex
var testAllChannelsRunning bool = false

// disable & notify
func disableChannel(channelId int, channelName string, reason string) {
	if common.RootUserEmail == "" {
		common.RootUserEmail = model.GetRootUserEmail()
	}
	model.UpdateChannelStatusById(channelId, common.ChannelStatusDisabled)
	subject := fmt.Sprintf("通道「%s」（#%d）已被禁用", channelName, channelId)
	content := fmt.Sprintf("通道「%s」（#%d）已被禁用，原因：%s", channelName, channelId, reason)
	err := common.SendEmail(subject, common.RootUserEmail, content)
	if err != nil {
		common.SysError(fmt.Sprintf("failed to send email: %s", err.Error()))
	}
}

func testAllChannels(notify bool) error {
	if common.RootUserEmail == "" {
		common.RootUserEmail = model.GetRootUserEmail()
	}
	testAllChannelsLock.Lock()
	if testAllChannelsRunning {
		testAllChannelsLock.Unlock()
		return errors.New("测试已在运行中")
	}
	testAllChannelsRunning = true
	testAllChannelsLock.Unlock()
	channels, err := model.GetAllChannels(0, 0, true)
	if err != nil {
		return err
	}
	testRequest := buildTestRequest()
	var disableThreshold = int64(common.ChannelDisableThreshold * 1000)
	if disableThreshold == 0 {
		disableThreshold = 10000000 // a impossible value
	}
	go func() {
		for _, channel := range channels {
			if channel.Status != common.ChannelStatusEnabled {
				continue
			}
			tik := time.Now()
			err := testChannel(channel, *testRequest)
			tok := time.Now()
			milliseconds := tok.Sub(tik).Milliseconds()
			if err != nil || milliseconds > disableThreshold {
				if milliseconds > disableThreshold {
					err = errors.New(fmt.Sprintf("响应时间 %.2fs 超过阈值 %.2fs", float64(milliseconds)/1000.0, float64(disableThreshold)/1000.0))
				}
				disableChannel(channel.Id, channel.Name, err.Error())
			}
			channel.UpdateResponseTime(milliseconds)
			time.Sleep(common.RequestInterval)
		}
		testAllChannelsLock.Lock()
		testAllChannelsRunning = false
		testAllChannelsLock.Unlock()
		if notify {
			err := common.SendEmail("通道测试完成", common.RootUserEmail, "通道测试完成，如果没有收到禁用通知，说明所有通道都正常")
			if err != nil {
				common.SysError(fmt.Sprintf("failed to send email: %s", err.Error()))
			}
		}
	}()
	return nil
}

func TestAllChannels(c *gin.Context) {
	err := testAllChannels(true)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
	})
	return
}

func AutomaticallyTestChannels(frequency int) {
	for {
		time.Sleep(time.Duration(frequency) * time.Minute)
		common.SysLog("testing all channels")
		_ = testAllChannels(false)
		common.SysLog("channel test finished")
	}
}