package service

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"time"

	"x-agents/server/internal/model"
	"x-agents/server/internal/repository"

	"github.com/google/uuid"
)

type ChatService struct {
	pythonURL  string
	agentRepo  *repository.AgentRepository
	modelRepo *repository.ModelRepository
}

func NewChatService(pythonURL string, agentRepo *repository.AgentRepository, modelRepo *repository.ModelRepository) *ChatService {
	return &ChatService{
		pythonURL:  pythonURL,
		agentRepo:  agentRepo,
		modelRepo: modelRepo,
	}
}

type ChatRequest struct {
	AgentID   string                 `json:"agent_id"`
	Message   string                 `json:"message"`
	SessionID string                 `json:"session_id"`
	ModelID   string                 `json:"model_id"`
	Context   map[string]interface{} `json:"context"`
}

// ModelConfig 模型配置，用于传递给 Python 服务
type ModelConfig struct {
	Provider    string `json:"provider"`
	Model       string `json:"model"`
	APIKey      string `json:"api_key"`
	BaseURL     string `json:"base_url"`
	APIEndpoint string `json:"api_endpoint"`
}

type ChatResponse struct {
	Reply     string                 `json:"reply"`
	SessionID string                 `json:"session_id"`
	ToolsUsed []string              `json:"tools_used"`
	Metadata  map[string]interface{} `json:"metadata"`
}

// Chat 处理聊天请求
func (s *ChatService) Chat(ctx context.Context, userID string, req model.AgentRequest) (*model.AgentResponse, error) {
	// 1. 检查 Agent 是否存在
	agent, err := s.agentRepo.FindByID(req.AgentID)
	if err != nil {
		return nil, fmt.Errorf("agent not found: %w", err)
	}

	// 2. 检查用户权限
	if !agent.IsActive {
		return nil, fmt.Errorf("agent is not active")
	}

	// 3. 生成会话ID
	sessionID := req.SessionID
	if sessionID == "" {
		sessionID = uuid.New().String()
	}

	// 4. 如果提供了 ModelID，获取模型配置
	var modelConfig *ModelConfig
	if req.ModelID != "" {
		modelInfo, err := s.modelRepo.FindByID(req.ModelID)
		if err != nil {
			return nil, fmt.Errorf("model not found: %w", err)
		}
		modelConfig = &ModelConfig{
			Provider:    modelInfo.Provider,
			Model:       modelInfo.Model,
			APIKey:      modelInfo.APIKey,
			BaseURL:     modelInfo.BaseURL,
			APIEndpoint: modelInfo.APIEndpoint,
		}
	}

	// 5. 调用 Python 服务
	pythonReq := ChatRequest{
		AgentID:   req.AgentID,
		Message:   req.Message,
		SessionID: sessionID,
		ModelID:   req.ModelID,
		Context:   req.Context,
	}

	// 将模型配置放入 Context 中传递给 Python 服务
	if modelConfig != nil {
		pythonReq.Context = make(map[string]interface{})
		for k, v := range req.Context {
			pythonReq.Context[k] = v
		}
		pythonReq.Context["model_config"] = modelConfig
	}

	pythonResp, err := s.callPythonChat(ctx, pythonReq)
	if err != nil {
		return nil, fmt.Errorf("failed to call python service: %w", err)
	}

	return &model.AgentResponse{
		Reply:     pythonResp.Reply,
		SessionID: pythonResp.SessionID,
		ToolsUsed: pythonResp.ToolsUsed,
		Metadata:  pythonResp.Metadata,
	}, nil
}

func (s *ChatService) callPythonChat(ctx context.Context, req ChatRequest) (*ChatResponse, error) {
	jsonData, err := json.Marshal(req)
	if err != nil {
		return nil, err
	}

	httpReq, err := http.NewRequestWithContext(
		ctx,
		"POST",
		s.pythonURL+"/agent/chat",
		bytes.NewBuffer(jsonData),
	)
	if err != nil {
		return nil, err
	}

	httpReq.Header.Set("Content-Type", "application/json")

	client := &http.Client{
		Timeout: 120 * time.Second, // Agent 可能需要较长时间
	}

	resp, err := client.Do(httpReq)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("python service returned status: %d", resp.StatusCode)
	}

	var chatResp ChatResponse
	if err := json.NewDecoder(resp.Body).Decode(&chatResp); err != nil {
		return nil, err
	}

	return &chatResp, nil
}

// ListAgents 获取用户可用的 Agent 列表
func (s *ChatService) ListAgents(userID string) ([]model.Agent, error) {
	return s.agentRepo.FindByOwnerID(userID)
}

// CreateAgent 创建新的 Agent
func (s *ChatService) CreateAgent(userID string, name, description string) (*model.Agent, error) {
	agent := &model.Agent{
		ID:          uuid.New().String(),
		Name:        name,
		Description: description,
		OwnerID:     userID,
		IsActive:    true,
	}

	if err := s.agentRepo.Create(agent); err != nil {
		return nil, err
	}

	return agent, nil
}