//
//  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 (
	"bufio"
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"ragflow/internal/logger"
	"strings"
	"time"
)

// SiliconflowModel implements ModelDriver for Siliconflow
type SiliconflowModel struct {
	BaseURL    map[string]string
	URLSuffix  URLSuffix
	httpClient *http.Client // Reusable HTTP client with connection pool
}

// NewSiliconflowModel creates a new Siliconflow model instance
func NewSiliconflowModel(baseURL map[string]string, urlSuffix URLSuffix) *SiliconflowModel {
	return &SiliconflowModel{
		BaseURL:   baseURL,
		URLSuffix: urlSuffix,
		httpClient: &http.Client{
			Timeout: 120 * time.Second,
			Transport: &http.Transport{
				MaxIdleConns:        100,
				MaxIdleConnsPerHost: 10,
				IdleConnTimeout:     90 * time.Second,
				DisableCompression:  false,
			},
		},
	}
}

func (z *SiliconflowModel) NewInstance(baseURL map[string]string) ModelDriver {
	return nil
}

func (z *SiliconflowModel) Name() string {
	return "siliconflow"
}

// SiliconflowRerankRequest represents SILICONFLOW rerank request
type SiliconflowRerankRequest struct {
	Model           string   `json:"model"`
	Query           string   `json:"query"`
	Documents       []string `json:"documents"`
	TopN            int      `json:"top_n"`
	ReturnDocuments bool     `json:"return_documents"`
	MaxChunksPerDoc int      `json:"max_chunks_per_doc"`
	OverlapTokens   int      `json:"overlap_tokens"`
}

// SiliconflowRerankResponse represents SILICONFLOW rerank response
type SiliconflowRerankResponse struct {
	Results []struct {
		Index          int     `json:"index"`
		RelevanceScore float64 `json:"relevance_score"`
	} `json:"results"`
}

// ChatWithMessages sends multiple messages with roles and returns response
func (z *SiliconflowModel) ChatWithMessages(modelName string, messages []Message, apiConfig *APIConfig, chatModelConfig *ChatConfig) (*ChatResponse, error) {
	if apiConfig == nil || apiConfig.ApiKey == nil || *apiConfig.ApiKey == "" {
		return nil, fmt.Errorf("api key is nil or empty")
	}

	if len(messages) == 0 {
		return nil, fmt.Errorf("messages is empty")
	}

	region := "default"
	if apiConfig.Region != nil {
		region = *apiConfig.Region
	}
	url := fmt.Sprintf("%s/%s", z.BaseURL[region], z.URLSuffix.Chat)

	// Convert messages to the format expected by API
	apiMessages := make([]map[string]interface{}, len(messages))
	for i, msg := range messages {
		apiMessages[i] = map[string]interface{}{
			"role":    msg.Role,
			"content": msg.Content,
		}
	}

	// Build request body
	reqBody := map[string]interface{}{
		"model":       modelName,
		"messages":    apiMessages,
		"stream":      false,
		"temperature": 1,
	}

	if chatModelConfig != nil {
		if chatModelConfig.Stream != nil {
			reqBody["stream"] = *chatModelConfig.Stream
		}

		if chatModelConfig.MaxTokens != nil {
			reqBody["max_tokens"] = *chatModelConfig.MaxTokens
		}

		if chatModelConfig.Temperature != nil {
			reqBody["temperature"] = *chatModelConfig.Temperature
		}

		if chatModelConfig.TopP != nil {
			reqBody["top_p"] = *chatModelConfig.TopP
		}

		if chatModelConfig.Stop != nil {
			reqBody["stop"] = *chatModelConfig.Stop
		}
	}

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

	req, err := http.NewRequest("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 := z.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 result map[string]interface{}
	if err := json.Unmarshal(body, &result); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}

	choices, ok := result["choices"].([]interface{})
	if !ok || len(choices) == 0 {
		return nil, fmt.Errorf("no choices in response")
	}

	firstChoice, ok := choices[0].(map[string]interface{})
	if !ok {
		return nil, fmt.Errorf("invalid choice format")
	}

	messageMap, ok := firstChoice["message"].(map[string]interface{})
	if !ok {
		return nil, fmt.Errorf("invalid message format")
	}

	content, ok := messageMap["content"].(string)
	if !ok {
		return nil, fmt.Errorf("invalid content format")
	}

	var reasonContent string
	if chatModelConfig != nil && chatModelConfig.Thinking != nil && *chatModelConfig.Thinking {
		reasonContent, ok = messageMap["reasoning_content"].(string)
		if !ok {
			// If reasoning_content not in response, try parsing from content tags
			reasoning, answer := GetThinkingAndAnswer(chatModelConfig.ModelClass, &content)
			if reasoning != nil {
				reasonContent = *reasoning
				content = *answer
			}
		} else {
			// if first char of reasonContent is \n remove the '\n'
			if reasonContent != "" && reasonContent[0] == '\n' {
				reasonContent = reasonContent[1:]
			}
		}
	}

	chatResponse := &ChatResponse{
		Answer:        &content,
		ReasonContent: &reasonContent,
	}

	return chatResponse, nil
}

// ChatStreamlyWithSender sends messages and streams response via sender function (best performance, no channel)
func (z *SiliconflowModel) ChatStreamlyWithSender(modelName string, messages []Message, apiConfig *APIConfig, chatModelConfig *ChatConfig, sender func(*string, *string) error) error {
	if len(messages) == 0 {
		return fmt.Errorf("messages is empty")
	}

	var region = "default"
	if apiConfig.Region != nil {
		region = *apiConfig.Region
	}

	url := fmt.Sprintf("%s/chat/completions", z.BaseURL[region])

	// Convert messages to API format
	apiMessages := make([]map[string]interface{}, len(messages))
	for i, msg := range messages {
		apiMessages[i] = map[string]interface{}{
			"role":    msg.Role,
			"content": msg.Content,
		}
	}

	// Build request body with streaming enabled
	reqBody := map[string]interface{}{
		"model":       modelName,
		"messages":    apiMessages,
		"stream":      true,
		"temperature": 1,
	}

	if chatModelConfig != nil {
		if chatModelConfig.Stream != nil {
			reqBody["stream"] = *chatModelConfig.Stream
		}

		if chatModelConfig.MaxTokens != nil {
			reqBody["max_tokens"] = *chatModelConfig.MaxTokens
		}

		if chatModelConfig.Temperature != nil {
			reqBody["temperature"] = *chatModelConfig.Temperature
		}

		if chatModelConfig.DoSample != nil {
			reqBody["do_sample"] = *chatModelConfig.DoSample
		}

		if chatModelConfig.TopP != nil {
			reqBody["top_p"] = *chatModelConfig.TopP
		}

		if chatModelConfig.Stop != nil {
			reqBody["stop"] = *chatModelConfig.Stop
		}

		if chatModelConfig.Thinking != nil {
			if *chatModelConfig.Thinking {
				reqBody["thinking"] = map[string]interface{}{
					"type": "enabled",
				}
			} else {
				reqBody["thinking"] = map[string]interface{}{
					"type": "disabled",
				}
			}
		}
	}

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

	req, err := http.NewRequest("POST", 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 := z.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))
	}

	// SSE parsing: read line by line
	scanner := bufio.NewScanner(resp.Body)
	for scanner.Scan() {
		line := scanner.Text()
		logger.Info(line)

		// SSE data line starts with "data:"
		if !strings.HasPrefix(line, "data:") {
			continue
		}

		// Extract JSON after "data:"
		data := strings.TrimSpace(line[5:])

		// [DONE] marks the end of stream
		if data == "[DONE]" {
			break
		}

		// Parse the JSON event
		var event map[string]interface{}
		if err = json.Unmarshal([]byte(data), &event); err != nil {
			continue
		}

		choices, ok := event["choices"].([]interface{})
		if !ok || len(choices) == 0 {
			continue
		}

		firstChoice, ok := choices[0].(map[string]interface{})
		if !ok {
			continue
		}

		delta, ok := firstChoice["delta"].(map[string]interface{})
		if !ok {
			continue
		}

		reasoningContent, ok := delta["reasoning_content"].(string)
		if ok && reasoningContent != "" {
			if err := sender(nil, &reasoningContent); err != nil {
				return err
			}
		}

		content, ok := delta["content"].(string)
		if ok && content != "" {
			if err := sender(&content, nil); err != nil {
				return err
			}
		}

		finishReason, ok := firstChoice["finish_reason"].(string)
		if ok && finishReason != "" {
			break
		}
	}

	// Send [DONE] marker for OpenAI compatibility
	endOfStream := "[DONE]"
	if err = sender(&endOfStream, nil); err != nil {
		return err
	}

	return scanner.Err()
}

// Encode encodes a list of texts into embeddings
func (s *SiliconflowModel) Encode(modelName *string, texts []string, apiConfig *APIConfig, embeddingConfig *EmbeddingConfig) ([][]float64, error) {
	if len(texts) == 0 {
		return [][]float64{}, nil
	}

	var region = "default"
	if apiConfig != nil && apiConfig.Region != nil {
		region = *apiConfig.Region
	}

	url := fmt.Sprintf("%s/%s", strings.TrimSuffix(s.BaseURL[region], "/"), s.URLSuffix.Embedding)

	apiKey := ""
	if apiConfig != nil && apiConfig.ApiKey != nil {
		apiKey = *apiConfig.ApiKey
	}

	embeddings := make([][]float64, len(texts))

	for i, text := range texts {
		reqBody := map[string]interface{}{
			"model": modelName,
			"input": text,
		}

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

		req, err := http.NewRequest("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")
		if apiKey != "" {
			req.Header.Set("Authorization", "Bearer "+apiKey)
		}

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

		body, err := io.ReadAll(resp.Body)
		resp.Body.Close()

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

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

		// Parse response
		var result map[string]interface{}
		if err = json.Unmarshal(body, &result); err != nil {
			return nil, fmt.Errorf("failed to parse response: %w", err)
		}

		data, ok := result["data"].([]interface{})
		if !ok || len(data) == 0 {
			return nil, fmt.Errorf("no data in response")
		}

		firstData, ok := data[0].(map[string]interface{})
		if !ok {
			return nil, fmt.Errorf("invalid data format")
		}

		embeddingSlice, ok := firstData["embedding"].([]interface{})
		if !ok {
			return nil, fmt.Errorf("invalid embedding format")
		}

		embedding := make([]float64, len(embeddingSlice))
		for j, v := range embeddingSlice {
			switch val := v.(type) {
			case float64:
				embedding[j] = val
			case float32:
				embedding[j] = float64(val)
			default:
				return nil, fmt.Errorf("unexpected embedding value type")
			}
		}

		embeddings[i] = embedding
	}

	return embeddings, nil
}

func (z *SiliconflowModel) ListModels(apiConfig *APIConfig) ([]string, error) {
	var region = "default"
	if apiConfig.Region != nil {
		region = *apiConfig.Region
	}

	url := fmt.Sprintf("%s/%s", z.BaseURL[region], z.URLSuffix.Models)

	// Build request body
	reqBody := map[string]interface{}{}

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

	req, err := http.NewRequest("GET", 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 := z.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 DSModelList
	if err = json.Unmarshal(body, &modelList); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}

	var models []string
	for _, model := range modelList.Models {
		modelName := model.ID
		if model.OwnedBy != "" {
			modelName = model.ID + "@" + model.OwnedBy
		}
		models = append(models, modelName)
	}

	return models, nil
}

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

func (z *SiliconflowModel) CheckConnection(apiConfig *APIConfig) error {
	_, err := z.ListModels(apiConfig)
	if err != nil {
		return err
	}
	return nil
}

// Rerank calculates similarity scores between query and texts
func (s *SiliconflowModel) Rerank(modelName *string, query string, texts []string, apiConfig *APIConfig) ([]float64, error) {
	if len(texts) == 0 {
		return []float64{}, nil
	}

	var region = "default"
	if apiConfig != nil && apiConfig.Region != nil {
		region = *apiConfig.Region
	}

	apiKey := ""
	if apiConfig != nil && apiConfig.ApiKey != nil {
		apiKey = *apiConfig.ApiKey
	}

	reqBody := SiliconflowRerankRequest{
		Model:           *modelName,
		Query:           query,
		Documents:       texts,
		TopN:            len(texts),
		ReturnDocuments: false,
		MaxChunksPerDoc: 1024,
		OverlapTokens:   80,
	}

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

	url := fmt.Sprintf("%s/%s", strings.TrimSuffix(s.BaseURL[region], "/"), s.URLSuffix.Rerank)

	req, err := http.NewRequest("POST", url, strings.NewReader(string(jsonData)))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")
	if apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+apiKey)
	}

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

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("SiliconFlow Rerank API error: %s, body: %s", resp.Status, string(body))
	}

	body, _ := io.ReadAll(resp.Body)

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

	scores := make([]float64, len(texts))
	for _, result := range rerankResp.Results {
		if result.Index >= 0 && result.Index < len(texts) {
			scores[result.Index] = result.RelevanceScore
		}
	}

	return scores, nil
}