package openai

import (
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	"github.com/QuantumNous/new-api/common"
	"github.com/QuantumNous/new-api/dto"
	"github.com/QuantumNous/new-api/logger"
	relaycommon "github.com/QuantumNous/new-api/relay/common"
	"github.com/QuantumNous/new-api/relay/helper"
	"github.com/QuantumNous/new-api/service"
	"github.com/QuantumNous/new-api/types"

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

func OaiResponsesToChatHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http.Response) (*dto.Usage, *types.NewAPIError) {
	if resp == nil || resp.Body == nil {
		return nil, types.NewOpenAIError(fmt.Errorf("invalid response"), types.ErrorCodeBadResponse, http.StatusInternalServerError)
	}

	defer service.CloseResponseBodyGracefully(resp)

	var responsesResp dto.OpenAIResponsesResponse
	const maxResponseBodyBytes = 10 << 20 // 10MB
	body, err := io.ReadAll(io.LimitReader(resp.Body, maxResponseBodyBytes+1))
	if err != nil {
		return nil, types.NewOpenAIError(err, types.ErrorCodeReadResponseBodyFailed, http.StatusInternalServerError)
	}
	if int64(len(body)) > maxResponseBodyBytes {
		return nil, types.NewOpenAIError(fmt.Errorf("response body exceeds %d bytes", maxResponseBodyBytes), types.ErrorCodeBadResponseBody, http.StatusInternalServerError)
	}

	if err := common.Unmarshal(body, &responsesResp); err != nil {
		return nil, types.NewOpenAIError(err, types.ErrorCodeBadResponseBody, http.StatusInternalServerError)
	}

	if oaiError := responsesResp.GetOpenAIError(); oaiError != nil && oaiError.Type != "" {
		return nil, types.WithOpenAIError(*oaiError, resp.StatusCode)
	}

	chatId := helper.GetResponseID(c)
	chatResp, usage, err := service.ResponsesResponseToChatCompletionsResponse(&responsesResp, chatId)
	if err != nil {
		return nil, types.NewOpenAIError(err, types.ErrorCodeBadResponseBody, http.StatusInternalServerError)
	}

	if usage == nil || usage.TotalTokens == 0 {
		text := service.ExtractOutputTextFromResponses(&responsesResp)
		usage = service.ResponseText2Usage(c, text, info.UpstreamModelName, info.GetEstimatePromptTokens())
		chatResp.Usage = *usage
	}

	chatBody, err := common.Marshal(chatResp)
	if err != nil {
		return nil, types.NewOpenAIError(err, types.ErrorCodeJsonMarshalFailed, http.StatusInternalServerError)
	}

	service.IOCopyBytesGracefully(c, resp, chatBody)
	return usage, nil
}

func OaiResponsesToChatStreamHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http.Response) (*dto.Usage, *types.NewAPIError) {
	if resp == nil || resp.Body == nil {
		return nil, types.NewOpenAIError(fmt.Errorf("invalid response"), types.ErrorCodeBadResponse, http.StatusInternalServerError)
	}

	defer service.CloseResponseBodyGracefully(resp)

	responseId := helper.GetResponseID(c)
	createAt := time.Now().Unix()
	model := info.UpstreamModelName

	var (
		usage       = &dto.Usage{}
		textBuilder strings.Builder
		sentStart   bool
		sentStop    bool
		streamErr   *types.NewAPIError
	)

	helper.StreamScannerHandler(c, resp, info, func(data string) bool {
		if streamErr != nil {
			return false
		}

		var streamResp dto.ResponsesStreamResponse
		if err := common.UnmarshalJsonStr(data, &streamResp); err != nil {
			logger.LogError(c, "failed to unmarshal responses stream event: "+err.Error())
			return true
		}

		switch streamResp.Type {
		case "response.created":
			if streamResp.Response != nil {
				if streamResp.Response.Model != "" {
					model = streamResp.Response.Model
				}
				if streamResp.Response.CreatedAt != 0 {
					createAt = int64(streamResp.Response.CreatedAt)
				}
			}

		case "response.output_text.delta":
			if !sentStart {
				if err := helper.ObjectData(c, helper.GenerateStartEmptyResponse(responseId, createAt, model, nil)); err != nil {
					streamErr = types.NewOpenAIError(err, types.ErrorCodeBadResponse, http.StatusInternalServerError)
					return false
				}
				sentStart = true
			}

			if streamResp.Delta != "" {
				textBuilder.WriteString(streamResp.Delta)
				delta := streamResp.Delta
				chunk := &dto.ChatCompletionsStreamResponse{
					Id:      responseId,
					Object:  "chat.completion.chunk",
					Created: createAt,
					Model:   model,
					Choices: []dto.ChatCompletionsStreamResponseChoice{
						{
							Index: 0,
							Delta: dto.ChatCompletionsStreamResponseChoiceDelta{
								Content: &delta,
							},
						},
					},
				}
				if err := helper.ObjectData(c, chunk); err != nil {
					streamErr = types.NewOpenAIError(err, types.ErrorCodeBadResponse, http.StatusInternalServerError)
					return false
				}
			}

		case "response.completed":
			if streamResp.Response != nil {
				if streamResp.Response.Model != "" {
					model = streamResp.Response.Model
				}
				if streamResp.Response.CreatedAt != 0 {
					createAt = int64(streamResp.Response.CreatedAt)
				}
				if streamResp.Response.Usage != nil {
					if streamResp.Response.Usage.InputTokens != 0 {
						usage.PromptTokens = streamResp.Response.Usage.InputTokens
						usage.InputTokens = streamResp.Response.Usage.InputTokens
					}
					if streamResp.Response.Usage.OutputTokens != 0 {
						usage.CompletionTokens = streamResp.Response.Usage.OutputTokens
						usage.OutputTokens = streamResp.Response.Usage.OutputTokens
					}
					if streamResp.Response.Usage.TotalTokens != 0 {
						usage.TotalTokens = streamResp.Response.Usage.TotalTokens
					} else {
						usage.TotalTokens = usage.PromptTokens + usage.CompletionTokens
					}
					if streamResp.Response.Usage.InputTokensDetails != nil {
						usage.PromptTokensDetails.CachedTokens = streamResp.Response.Usage.InputTokensDetails.CachedTokens
						usage.PromptTokensDetails.ImageTokens = streamResp.Response.Usage.InputTokensDetails.ImageTokens
						usage.PromptTokensDetails.AudioTokens = streamResp.Response.Usage.InputTokensDetails.AudioTokens
					}
					if streamResp.Response.Usage.CompletionTokenDetails.ReasoningTokens != 0 {
						usage.CompletionTokenDetails.ReasoningTokens = streamResp.Response.Usage.CompletionTokenDetails.ReasoningTokens
					}
				}
			}

			if !sentStart {
				if err := helper.ObjectData(c, helper.GenerateStartEmptyResponse(responseId, createAt, model, nil)); err != nil {
					streamErr = types.NewOpenAIError(err, types.ErrorCodeBadResponse, http.StatusInternalServerError)
					return false
				}
				sentStart = true
			}
			if !sentStop {
				stop := helper.GenerateStopResponse(responseId, createAt, model, "stop")
				if err := helper.ObjectData(c, stop); err != nil {
					streamErr = types.NewOpenAIError(err, types.ErrorCodeBadResponse, http.StatusInternalServerError)
					return false
				}
				sentStop = true
			}

		case "response.error", "response.failed":
			if streamResp.Response != nil {
				if oaiErr := streamResp.Response.GetOpenAIError(); oaiErr != nil && oaiErr.Type != "" {
					streamErr = types.WithOpenAIError(*oaiErr, http.StatusInternalServerError)
					return false
				}
			}
			streamErr = types.NewOpenAIError(fmt.Errorf("responses stream error: %s", streamResp.Type), types.ErrorCodeBadResponse, http.StatusInternalServerError)
			return false

		case "response.output_item.added", "response.output_item.done":

		default:
		}

		return true
	})

	if streamErr != nil {
		return nil, streamErr
	}

	if usage.TotalTokens == 0 {
		usage = service.ResponseText2Usage(c, textBuilder.String(), info.UpstreamModelName, info.GetEstimatePromptTokens())
	}

	if !sentStart {
		if err := helper.ObjectData(c, helper.GenerateStartEmptyResponse(responseId, createAt, model, nil)); err != nil {
			return nil, types.NewOpenAIError(err, types.ErrorCodeBadResponse, http.StatusInternalServerError)
		}
	}
	if !sentStop {
		stop := helper.GenerateStopResponse(responseId, createAt, model, "stop")
		if err := helper.ObjectData(c, stop); err != nil {
			return nil, types.NewOpenAIError(err, types.ErrorCodeBadResponse, http.StatusInternalServerError)
		}
	}
	if info.ShouldIncludeUsage && usage != nil {
		if err := helper.ObjectData(c, helper.GenerateFinalUsageResponse(responseId, createAt, model, *usage)); err != nil {
			return nil, types.NewOpenAIError(err, types.ErrorCodeBadResponse, http.StatusInternalServerError)
		}
	}

	helper.Done(c)
	return usage, nil
}