package gemini

import (
	"bufio"
	"encoding/json"
	"fmt"
	"github.com/gin-gonic/gin"
	"io"
	"net/http"
	"one-api/common"
	"one-api/dto"
	relaycommon "one-api/relay/common"
	"one-api/service"
	"strings"
)

// Setting safety to the lowest possible values since Gemini is already powerless enough
func CovertGemini2OpenAI(textRequest dto.GeneralOpenAIRequest) *GeminiChatRequest {
	geminiRequest := GeminiChatRequest{
		Contents: make([]GeminiChatContent, 0, len(textRequest.Messages)),
		SafetySettings: []GeminiChatSafetySettings{
			{
				Category:  "HARM_CATEGORY_HARASSMENT",
				Threshold: common.GeminiSafetySetting,
			},
			{
				Category:  "HARM_CATEGORY_HATE_SPEECH",
				Threshold: common.GeminiSafetySetting,
			},
			{
				Category:  "HARM_CATEGORY_SEXUALLY_EXPLICIT",
				Threshold: common.GeminiSafetySetting,
			},
			{
				Category:  "HARM_CATEGORY_DANGEROUS_CONTENT",
				Threshold: common.GeminiSafetySetting,
			},
		},
		GenerationConfig: GeminiChatGenerationConfig{
			Temperature:     textRequest.Temperature,
			TopP:            textRequest.TopP,
			MaxOutputTokens: textRequest.MaxTokens,
		},
	}
	if textRequest.Tools != nil {
		functions := make([]dto.FunctionCall, 0, len(textRequest.Tools))
		for _, tool := range textRequest.Tools {
			functions = append(functions, tool.Function)
		}
		geminiRequest.Tools = []GeminiChatTools{
			{
				FunctionDeclarations: functions,
			},
		}
	} else if textRequest.Functions != nil {
		geminiRequest.Tools = []GeminiChatTools{
			{
				FunctionDeclarations: textRequest.Functions,
			},
		}
	}
	shouldAddDummyModelMessage := false
	for _, message := range textRequest.Messages {
		content := GeminiChatContent{
			Role: message.Role,
			Parts: []GeminiPart{
				{
					Text: message.StringContent(),
				},
			},
		}
		openaiContent := message.ParseContent()
		var parts []GeminiPart
		imageNum := 0
		for _, part := range openaiContent {

			if part.Type == dto.ContentTypeText {
				parts = append(parts, GeminiPart{
					Text: part.Text,
				})
			} else if part.Type == dto.ContentTypeImageURL {
				imageNum += 1
				if imageNum > GeminiVisionMaxImageNum {
					continue
				}
				// 判断是否是url
				if strings.HasPrefix(part.ImageUrl.(dto.MessageImageUrl).Url, "http") {
					// 是url，获取图片的类型和base64编码的数据
					mimeType, data, _ := service.GetImageFromUrl(part.ImageUrl.(dto.MessageImageUrl).Url)
					parts = append(parts, GeminiPart{
						InlineData: &GeminiInlineData{
							MimeType: mimeType,
							Data:     data,
						},
					})
				}
				else{
					_, format, base64String, err := service.DecodeBase64ImageData(part.ImageUrl.(dto.MessageImageUrl).Url)
					if err != nil {
						return nil, err
					}
					parts = append(parts, GeminiPart{
						InlineData: &GeminiInlineData{
							MimeType: "image/" + format,
							Data:     base64String,
						},
					})
				}
			}
		}
		content.Parts = parts

		// there's no assistant role in gemini and API shall vomit if Role is not user or model
		if content.Role == "assistant" {
			content.Role = "model"
		}
		// Converting system prompt to prompt from user for the same reason
		if content.Role == "system" {
			content.Role = "user"
			shouldAddDummyModelMessage = true
		}
		geminiRequest.Contents = append(geminiRequest.Contents, content)

		// If a system message is the last message, we need to add a dummy model message to make gemini happy
		if shouldAddDummyModelMessage {
			geminiRequest.Contents = append(geminiRequest.Contents, GeminiChatContent{
				Role: "model",
				Parts: []GeminiPart{
					{
						Text: "Okay",
					},
				},
			})
			shouldAddDummyModelMessage = false
		}
	}

	return &geminiRequest
}

func (g *GeminiChatResponse) GetResponseText() string {
	if g == nil {
		return ""
	}
	if len(g.Candidates) > 0 && len(g.Candidates[0].Content.Parts) > 0 {
		return g.Candidates[0].Content.Parts[0].Text
	}
	return ""
}

func getToolCalls(candidate *GeminiChatCandidate) []dto.ToolCall {
	var toolCalls []dto.ToolCall

	item := candidate.Content.Parts[0]
	if item.FunctionCall == nil {
		return toolCalls
	}
	argsBytes, err := json.Marshal(item.FunctionCall.Arguments)
	if err != nil {
		//common.SysError("getToolCalls failed: " + err.Error())
		return toolCalls
	}
	toolCall := dto.ToolCall{
		ID:   fmt.Sprintf("call_%s", common.GetUUID()),
		Type: "function",
		Function: dto.FunctionCall{
			Arguments: string(argsBytes),
			Name:      item.FunctionCall.FunctionName,
		},
	}
	toolCalls = append(toolCalls, toolCall)
	return toolCalls
}

func responseGeminiChat2OpenAI(response *GeminiChatResponse) *dto.OpenAITextResponse {
	fullTextResponse := dto.OpenAITextResponse{
		Id:      fmt.Sprintf("chatcmpl-%s", common.GetUUID()),
		Object:  "chat.completion",
		Created: common.GetTimestamp(),
		Choices: make([]dto.OpenAITextResponseChoice, 0, len(response.Candidates)),
	}
	content, _ := json.Marshal("")
	for i, candidate := range response.Candidates {
		choice := dto.OpenAITextResponseChoice{
			Index: i,
			Message: dto.Message{
				Role:    "assistant",
				Content: content,
			},
			FinishReason: relaycommon.StopFinishReason,
		}
		if len(candidate.Content.Parts) > 0 {
			if candidate.Content.Parts[0].FunctionCall != nil {
				choice.Message.ToolCalls = getToolCalls(&candidate)
			} else {
				choice.Message.SetStringContent(candidate.Content.Parts[0].Text)
			}
		}
		fullTextResponse.Choices = append(fullTextResponse.Choices, choice)
	}
	return &fullTextResponse
}

func streamResponseGeminiChat2OpenAI(geminiResponse *GeminiChatResponse) *dto.ChatCompletionsStreamResponse {
	var choice dto.ChatCompletionsStreamResponseChoice
	//choice.Delta.SetContentString(geminiResponse.GetResponseText())
	if len(geminiResponse.Candidates) > 0 && len(geminiResponse.Candidates[0].Content.Parts) > 0 {
		respFirst := geminiResponse.Candidates[0].Content.Parts[0]
		if respFirst.FunctionCall != nil {
			// function response
			choice.Delta.ToolCalls = getToolCalls(&geminiResponse.Candidates[0])
		} else {
			// text response
			choice.Delta.SetContentString(respFirst.Text)
		}
	}
	var response dto.ChatCompletionsStreamResponse
	response.Object = "chat.completion.chunk"
	response.Model = "gemini"
	response.Choices = []dto.ChatCompletionsStreamResponseChoice{choice}
	return &response
}

func geminiChatStreamHandler(c *gin.Context, resp *http.Response, info *relaycommon.RelayInfo) (*dto.OpenAIErrorWithStatusCode, *dto.Usage) {
	responseText := ""
	id := fmt.Sprintf("chatcmpl-%s", common.GetUUID())
	createAt := common.GetTimestamp()
	var usage = &dto.Usage{}
	scanner := bufio.NewScanner(resp.Body)
	scanner.Split(bufio.ScanLines)

	service.SetEventStreamHeaders(c)
	for scanner.Scan() {
		data := scanner.Text()
		info.SetFirstResponseTime()
		data = strings.TrimSpace(data)
		if !strings.HasPrefix(data, "data: ") {
			continue
		}
		data = strings.TrimPrefix(data, "data: ")
		data = strings.TrimSuffix(data, "\"")
		var geminiResponse GeminiChatResponse
		err := json.Unmarshal([]byte(data), &geminiResponse)
		if err != nil {
			common.LogError(c, "error unmarshalling stream response: "+err.Error())
			continue
		}

		response := streamResponseGeminiChat2OpenAI(&geminiResponse)
		if response == nil {
			continue
		}
		response.Id = id
		response.Created = createAt
		responseText += response.Choices[0].Delta.GetContentString()
		if geminiResponse.UsageMetadata.TotalTokenCount != 0 {
			usage.PromptTokens = geminiResponse.UsageMetadata.PromptTokenCount
			usage.CompletionTokens = geminiResponse.UsageMetadata.CandidatesTokenCount
		}
		err = service.ObjectData(c, response)
		if err != nil {
			common.LogError(c, err.Error())
		}
	}

	response := service.GenerateStopResponse(id, createAt, info.UpstreamModelName, relaycommon.StopFinishReason)
	service.ObjectData(c, response)

	usage.TotalTokens = usage.PromptTokens + usage.CompletionTokens

	if info.ShouldIncludeUsage {
		response = service.GenerateFinalUsageResponse(id, createAt, info.UpstreamModelName, *usage)
		err := service.ObjectData(c, response)
		if err != nil {
			common.SysError("send final response failed: " + err.Error())
		}
	}
	service.Done(c)
	resp.Body.Close()
	return nil, usage
}

func geminiChatHandler(c *gin.Context, resp *http.Response, promptTokens int, model string) (*dto.OpenAIErrorWithStatusCode, *dto.Usage) {
	responseBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return service.OpenAIErrorWrapper(err, "read_response_body_failed", http.StatusInternalServerError), nil
	}
	err = resp.Body.Close()
	if err != nil {
		return service.OpenAIErrorWrapper(err, "close_response_body_failed", http.StatusInternalServerError), nil
	}
	var geminiResponse GeminiChatResponse
	err = json.Unmarshal(responseBody, &geminiResponse)
	if err != nil {
		return service.OpenAIErrorWrapper(err, "unmarshal_response_body_failed", http.StatusInternalServerError), nil
	}
	if len(geminiResponse.Candidates) == 0 {
		return &dto.OpenAIErrorWithStatusCode{
			Error: dto.OpenAIError{
				Message: "No candidates returned",
				Type:    "server_error",
				Param:   "",
				Code:    500,
			},
			StatusCode: resp.StatusCode,
		}, nil
	}
	fullTextResponse := responseGeminiChat2OpenAI(&geminiResponse)
	usage := dto.Usage{
		PromptTokens:     geminiResponse.UsageMetadata.PromptTokenCount,
		CompletionTokens: geminiResponse.UsageMetadata.CandidatesTokenCount,
		TotalTokens:      geminiResponse.UsageMetadata.TotalTokenCount,
	}
	fullTextResponse.Usage = usage
	jsonResponse, err := json.Marshal(fullTextResponse)
	if err != nil {
		return service.OpenAIErrorWrapper(err, "marshal_response_body_failed", http.StatusInternalServerError), nil
	}
	c.Writer.Header().Set("Content-Type", "application/json")
	c.Writer.WriteHeader(resp.StatusCode)
	_, err = c.Writer.Write(jsonResponse)
	return nil, &usage
}