//
//  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

package models

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"ragflow/internal/common"
	"strings"
)

// HunyuanModel implements ModelDriver for Tencent Hunyuan
type HunyuanModel struct {
	baseModel BaseModel
}

// NewHunyuanModel creates a new Hunyuan model instance.
func NewHunyuanModel(baseURL map[string]string, urlSuffix URLSuffix) *HunyuanModel {
	return &HunyuanModel{
		baseModel: BaseModel{
			BaseURL:    baseURL,
			URLSuffix:  urlSuffix,
			httpClient: NewDriverHTTPClient(false),
		},
	}
}

func (h *HunyuanModel) NewInstance(baseURL map[string]string) ModelDriver {
	return NewHunyuanModel(baseURL, h.baseModel.URLSuffix)
}

func (h *HunyuanModel) Name() string {
	return "Tencent Hunyuan"
}

// HunyuanChatResponse mirrors Tencent Hunyuan's OpenAI-compatible chat response.
type HunyuanChatResponse struct {
	ID      string `json:"id"`
	Object  string `json:"object"`
	Created int64  `json:"created"`
	Model   string `json:"model"`
	Choices []struct {
		FinishReason string `json:"finish_reason"`
		Index        int    `json:"index"`
		Logprobs     any    `json:"logprobs"`
		Message      struct {
			Content          string           `json:"content"`
			Reasoning        string           `json:"reasoning"`
			ReasoningContent string           `json:"reasoning_content"`
			Role             string           `json:"role"`
			ToolCalls        []map[string]any `json:"tool_calls"`
		} `json:"message"`
	} `json:"choices"`
	SystemFingerprint string `json:"system_fingerprint"`
	Usage             struct {
		CompletionTokens int `json:"completion_tokens"`
		PromptTokens     int `json:"prompt_tokens"`
		TotalTokens      int `json:"total_tokens"`
	} `json:"usage"`
}

// HunyuanEmbeddingResponse mirrors Tencent Hunyuan's embeddings response.
type HunyuanEmbeddingResponse struct {
	ID     string `json:"id"`
	Object string `json:"object"`
	Model  string `json:"model"`
	Data   []struct {
		Object    string    `json:"object"`
		Embedding []float64 `json:"embedding"`
		Index     int       `json:"index"`
	} `json:"data"`
	Usage struct {
		PromptTokens     int `json:"prompt_tokens"`
		CompletionTokens int `json:"completion_tokens"`
		TotalTokens      int `json:"total_tokens"`
	} `json:"usage"`
}

func (h *HunyuanModel) ChatWithMessages(ctx context.Context, modelName string, messages []Message, apiConfig *APIConfig, chatModelConfig *ChatConfig, modelUsage *common.ModelUsage) (*ChatResponse, error) {
	if err := h.baseModel.APIConfigCheck(apiConfig); err != nil {
		return nil, err
	}
	if len(messages) == 0 {
		return nil, fmt.Errorf("messages is empty")
	}

	baseURL, err := h.baseModel.GetBaseURL(apiConfig)
	if err != nil {
		return nil, err
	}
	baseURL = strings.TrimSuffix(baseURL, "/")
	url := fmt.Sprintf("%s/%s", baseURL, h.baseModel.URLSuffix.Chat)
	reqBody := buildRequestBody(chatModelConfig, modelName, messages, false)

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal request: %w", err)
	}

	ctx, cancel := context.WithTimeout(ctx, nonStreamCallTimeout)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", *apiConfig.ApiKey))

	resp, err := h.baseModel.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("API request failed with status %d: %s", resp.StatusCode, string(body))
	}

	return parseChatCompletionResponse(body, chatModelConfig, modelUsage, func(body []byte, _ *ChatConfig) (chatResponseParts, error) {
		var result HunyuanChatResponse
		if err := json.Unmarshal(body, &result); err != nil {
			return chatResponseParts{}, fmt.Errorf("failed to parse response: %w", err)
		}
		if len(result.Choices) == 0 {
			return chatResponseParts{}, fmt.Errorf("no choices in response")
		}

		choice := result.Choices[0]
		if choice.Message.Content == "" && len(choice.Message.ToolCalls) == 0 {
			return chatResponseParts{}, fmt.Errorf("response contains neither content nor tool calls")
		}
		reasonContent := choice.Message.ReasoningContent
		if reasonContent == "" {
			reasonContent = choice.Message.Reasoning
		}
		return chatResponseParts{
			RequestID:     result.ID,
			Content:       &choice.Message.Content,
			ReasonContent: &reasonContent,
			ToolCalls:     choice.Message.ToolCalls,
			Usage: &TokenUsage{
				PromptTokens:     result.Usage.PromptTokens,
				CompletionTokens: result.Usage.CompletionTokens,
				TotalTokens:      result.Usage.TotalTokens,
			},
		}, nil
	})
}

// ChatStreamlyWithSender opens the SSE chat-completions
func (h *HunyuanModel) ChatStreamlyWithSender(ctx context.Context, modelName string, messages []Message, apiConfig *APIConfig, chatModelConfig *ChatConfig, modelUsage *common.ModelUsage, sender func(*string, *string) error) error {
	if err := h.baseModel.APIConfigCheck(apiConfig); err != nil {
		return err
	}

	if sender == nil {
		return fmt.Errorf("sender is required")
	}
	if len(messages) == 0 {
		return fmt.Errorf("messages is empty")
	}
	if err := validateStreamConfig(chatModelConfig); err != nil {
		return err
	}
	if chatModelConfig != nil {
		chatModelConfig.ToolCallsResult = nil
		chatModelConfig.UsageResult = nil
	}

	baseURL, err := h.baseModel.GetBaseURL(apiConfig)
	if err != nil {
		return err
	}
	baseURL = strings.TrimSuffix(baseURL, "/")
	url := fmt.Sprintf("%s/%s", baseURL, h.baseModel.URLSuffix.Chat)
	reqBody := buildRequestBody(chatModelConfig, modelName, messages, true)
	reqBody["stream_options"] = map[string]any{"include_usage": true}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return fmt.Errorf("failed to marshal request: %w", err)
	}

	ctx, cancel := context.WithTimeout(ctx, streamCallTimeout)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewBuffer(jsonData))
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", *apiConfig.ApiKey))

	resp, err := h.baseModel.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API request failed with status %d: %s", resp.StatusCode, string(body))
	}

	sawTerminal := false
	accumulatedToolCalls := make(map[int]map[string]any)
	done, err := ParseSSEStream[map[string]any](resp.Body, func(event map[string]any) error {
		common.Info(fmt.Sprintf("%v", event))

		if apiErr, ok := event["error"]; ok {
			return fmt.Errorf("hunyuan: upstream stream error: %v", apiErr)
		}
		tokenUsage, found, usageErr := decodeOpenAICompatibleStreamUsage(event)
		if usageErr != nil {
			return usageErr
		}
		if found {
			applyStreamUsage(chatModelConfig, modelUsage, tokenUsage)
		}
		choices, ok := event["choices"].([]any)
		if !ok || len(choices) == 0 {
			return nil
		}

		choice, ok := choices[0].(map[string]any)
		if !ok {
			return nil
		}
		if finishReason, ok := choice["finish_reason"].(string); ok && finishReason != "" {
			sawTerminal = true
		}
		delta, ok := choice["delta"].(map[string]any)
		if !ok {
			return nil
		}
		accumulateToolCallDeltas(delta, accumulatedToolCalls)
		if reasoning, ok := delta["reasoning_content"].(string); ok && reasoning != "" {
			if err := sender(nil, &reasoning); err != nil {
				return err
			}
		}
		if reasoning, ok := delta["reasoning"].(string); ok && reasoning != "" {
			if err := sender(nil, &reasoning); err != nil {
				return err
			}
		}
		if content, ok := delta["content"].(string); ok && content != "" {
			if err := sender(&content, nil); err != nil {
				return err
			}
		}
		return nil
	})
	if err != nil {
		return fmt.Errorf("failed to scan response body: %w", err)
	}
	setSortedToolCallsResult(chatModelConfig, accumulatedToolCalls)
	if !done && !sawTerminal {
		return fmt.Errorf("hunyuan: stream ended before [DONE] or finish_reason")
	}

	endOfStream := "[DONE]"
	if err := sender(&endOfStream, nil); err != nil {
		return err
	}
	return nil
}

func (h *HunyuanModel) ListModels(ctx context.Context, apiConfig *APIConfig) ([]ListModelResponse, error) {
	if err := h.baseModel.APIConfigCheck(apiConfig); err != nil {
		return nil, err
	}

	baseURL, err := h.baseModel.GetBaseURL(apiConfig)
	if err != nil {
		return nil, err
	}
	baseURL = strings.TrimSuffix(baseURL, "/")
	url := fmt.Sprintf("%s/%s", baseURL, h.baseModel.URLSuffix.Models)

	ctx, cancel := context.WithTimeout(ctx, nonStreamCallTimeout)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", *apiConfig.ApiKey))

	resp, err := h.baseModel.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("API request failed with status %d: %s", resp.StatusCode, string(body))
	}

	// Parse response
	var modelList ModelList
	if err = json.Unmarshal(body, &modelList); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}
	if modelList.Models == nil {
		return nil, fmt.Errorf("invalid models list format")
	}

	return ParseListModel(modelList), nil
}

func (h *HunyuanModel) CheckConnection(ctx context.Context, apiConfig *APIConfig) error {
	_, err := h.ListModels(ctx, apiConfig)
	return err
}

func (h *HunyuanModel) Embed(ctx context.Context, modelName *string, texts []string, apiConfig *APIConfig, embeddingConfig *EmbeddingConfig, modelUsage *common.ModelUsage) ([]EmbeddingData, error) {
	if err := h.baseModel.APIConfigCheck(apiConfig); err != nil {
		return nil, err
	}

	if len(texts) == 0 {
		return []EmbeddingData{}, nil
	}
	if modelName == nil || *modelName == "" {
		return nil, fmt.Errorf("model name is required")
	}

	baseURL, err := h.baseModel.GetBaseURL(apiConfig)
	if err != nil {
		return nil, err
	}
	baseURL = strings.TrimSuffix(baseURL, "/")
	url := fmt.Sprintf("%s/%s", baseURL, h.baseModel.URLSuffix.Embedding)

	reqBody := map[string]interface{}{
		"model": *modelName,
		"input": texts,
	}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal request: %w", err)
	}

	ctx, cancel := context.WithTimeout(ctx, nonStreamCallTimeout)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", *apiConfig.ApiKey))

	resp, err := h.baseModel.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("Hunyuan embedding API error: status %d, body: %s", resp.StatusCode, string(body))
	}

	var parsedResponse HunyuanEmbeddingResponse

	if err = json.Unmarshal(body, &parsedResponse); err != nil {
		return nil, fmt.Errorf("failed to decode response: %w", err)
	}

	if len(parsedResponse.Data) == 0 {
		return nil, fmt.Errorf("hunyuan embedding response contains no data: %s", string(body))
	}
	recordResponseUsage(modelUsage, parsedResponse.ID, &TokenUsage{
		PromptTokens:     parsedResponse.Usage.PromptTokens,
		CompletionTokens: parsedResponse.Usage.CompletionTokens,
		TotalTokens:      parsedResponse.Usage.TotalTokens,
	}, "embedding")

	embeddings := make([]EmbeddingData, 0, len(parsedResponse.Data))
	for _, dataElem := range parsedResponse.Data {
		embeddings = append(embeddings, EmbeddingData{
			Embedding: dataElem.Embedding,
			Index:     dataElem.Index,
		})
	}

	return embeddings, nil
}

func (h *HunyuanModel) Rerank(ctx context.Context, modelName *string, query string, documents []string, apiConfig *APIConfig, rerankConfig *RerankConfig, modelUsage *common.ModelUsage) (*RerankResponse, error) {
	return nil, fmt.Errorf("%s, no such method", h.Name())
}

func (h *HunyuanModel) Balance(ctx context.Context, apiConfig *APIConfig) (map[string]interface{}, error) {
	return nil, fmt.Errorf("%s, no such method", h.Name())
}

func (h *HunyuanModel) TranscribeAudio(ctx context.Context, modelName *string, file *string, apiConfig *APIConfig, asrConfig *ASRConfig, modelUsage *common.ModelUsage) (*ASRResponse, error) {
	return nil, fmt.Errorf("%s, no such method", h.Name())
}

func (h *HunyuanModel) TranscribeAudioWithSender(ctx context.Context, modelName *string, file *string, apiConfig *APIConfig, asrConfig *ASRConfig, modelUsage *common.ModelUsage, sender func(*string, *string) error) error {
	return fmt.Errorf("%s, no such method", h.Name())
}

func (h *HunyuanModel) AudioSpeech(ctx context.Context, modelName *string, audioContent *string, apiConfig *APIConfig, ttsConfig *TTSConfig, modelUsage *common.ModelUsage) (*TTSResponse, error) {
	return nil, fmt.Errorf("%s, no such method", h.Name())
}

func (h *HunyuanModel) AudioSpeechWithSender(ctx context.Context, modelName *string, audioContent *string, apiConfig *APIConfig, ttsConfig *TTSConfig, modelUsage *common.ModelUsage, sender func(*string, *string) error) error {
	return fmt.Errorf("%s, no such method", h.Name())
}

func (h *HunyuanModel) OCRFile(ctx context.Context, modelName *string, content []byte, url *string, apiConfig *APIConfig, ocrConfig *OCRConfig, modelUsage *common.ModelUsage) (*OCRFileResponse, error) {
	return nil, fmt.Errorf("%s, no such method", h.Name())
}

func (h *HunyuanModel) ParseFile(ctx context.Context, modelName *string, content []byte, url *string, apiConfig *APIConfig, parseFileConfig *ParseFileConfig, modelUsage *common.ModelUsage) (*ParseFileResponse, error) {
	return nil, fmt.Errorf("%s, no such method", h.Name())
}

func (h *HunyuanModel) ListTasks(ctx context.Context, apiConfig *APIConfig) ([]ListTaskStatus, error) {
	return nil, fmt.Errorf("%s, no such method", h.Name())
}

func (h *HunyuanModel) ShowTask(ctx context.Context, taskID string, apiConfig *APIConfig) (*TaskResponse, error) {
	return nil, fmt.Errorf("%s, no such method", h.Name())
}
