package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	"github.com/joho/godotenv"
)

func main() {
	// Load .env file if it exists
	if err := godotenv.Load(); err != nil {
		log.Println("No .env file found, using environment variables")
	}

	// Load configuration
	cfg, err := LoadConfig()
	if err != nil {
		log.Fatalf("Failed to load configuration: %v", err)
	}

	// Test OpenAI connectivity
	log.Printf("Testing connectivity to OpenAI API...")
	retryDelay := time.Duration(cfg.LLMRetryDelay) * time.Second
	llm := NewLLMWithRetry(cfg.OpenAIKey, cfg.OpenAIModel, float32(cfg.OpenAITemperature), cfg.OpenAIBaseURL, cfg.OpenAIMaxTokens, cfg.LLMMaxRetries, retryDelay)
	if err := llm.TestConnection(context.Background()); err != nil {
		log.Fatalf("Failed to connect to OpenAI API: %v", err)
	}
	log.Printf("✓ Successfully connected to OpenAI API (max retries: %d, retry delay: %v)", cfg.LLMMaxRetries, retryDelay)

	// Login to ARP server
	log.Printf("Connecting to ARP server at %s...", cfg.ARPURL)
	token, err := login(cfg.ARPURL, cfg.ARPUsername, cfg.ARPPassword)
	if err != nil {
		log.Fatalf("Failed to login: %v", err)
	}
	log.Printf("Successfully authenticated with ARP server")

	// Connect to MCP server
	log.Printf("Connecting to MCP server...")
	mcpClient := NewMCPClient(cfg.ARPURL, token)
	if err := mcpClient.Connect(); err != nil {
		log.Fatalf("Failed to connect to MCP: %v", err)
	}

	// Initialize MCP
	initResult, err := mcpClient.Initialize()
	if err != nil {
		mcpClient.Close()
		log.Fatalf("Failed to initialize MCP: %v", err)
	}
	log.Printf("Connected to MCP server: %s v%s", initResult.ServerInfo.Name, initResult.ServerInfo.Version)

	// Create MCP manager to aggregate ARP + external servers
	mcpManager := NewMCPManager(mcpClient)

	// Load external MCP servers from config file if specified
	if cfg.MCPConfigPath != "" {
		log.Printf("Loading MCP server configuration from %s", cfg.MCPConfigPath)
		mcpConfig, err := LoadMCPConfig(cfg.MCPConfigPath)
		if err != nil {
			mcpManager.Close()
			log.Fatalf("Failed to load MCP config: %v", err)
		}

		for name, serverConfig := range mcpConfig.MCPServers {
			if err := mcpManager.AddExternalServer(name, serverConfig); err != nil {
				log.Printf("Warning: Failed to add external MCP server '%s': %v", name, err)
			}
		}
	}

	// Initialize the manager (discovers ARP tools)
	if err := mcpManager.Initialize(); err != nil {
		mcpManager.Close()
		log.Fatalf("Failed to initialize MCP manager: %v", err)
	}
	log.Printf("MCP manager initialized with %d tools from %d servers", mcpManager.GetToolCount(), len(mcpManager.GetServerNames()))

	// Create and initialize agent
	agent := NewAgent(llm, mcpManager, cfg)
	if err := agent.Initialize(); err != nil {
		mcpManager.Close()
		log.Fatalf("Failed to initialize agent: %v", err)
	}
	log.Printf("Agent initialized successfully.")

	// Setup event queues
	agent.SetupQueues(cfg.MaxQueueSize)
	log.Printf("Event queues initialized with capacity: %d", cfg.MaxQueueSize)

	// List and subscribe to resources
	log.Printf("Subscribing to ARP resources...")
	resources, err := mcpManager.ListResources()
	if err != nil {
		mcpManager.Close()
		log.Fatalf("Failed to list resources: %v", err)
	}

	log.Printf("Available resources: %v", resourceURIs(resources))
	for _, resource := range resources {
		log.Printf("  Subscribed to: %s", resource.URI)
		if err := mcpManager.SubscribeResource(resource.URI); err != nil {
			log.Printf("Warning: Failed to subscribe to %s: %v", resource.URI, err)
		}
	}

	// Handle graceful shutdown
	ctx, cancel := context.WithCancel(context.Background())

	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)

	go func() {
		<-sigChan
		log.Println("Received shutdown signal, stopping...")
		cancel()
	}()

	// Start the agent queue processor
	agent.Start(ctx)
	defer agent.Stop()

	// Listen for events with reconnection support
	log.Println()
	log.Println("Listening for events. Press Ctrl+C to stop.")

	reconnectDelay := time.Duration(cfg.MCPReconnectDelay) * time.Second

	for {
		select {
		case <-ctx.Done():
			mcpManager.Close()
			return
		case event, ok := <-mcpManager.Notifications():
			if !ok {
				// Notification channel closed - attempt to reconnect
				log.Printf("Notification channel closed, attempting to reconnect in %v...", reconnectDelay)

				select {
				case <-ctx.Done():
					mcpManager.Close()
					return
				case <-time.After(reconnectDelay):
					// Try to reconnect
					if err := reconnectMCP(cfg, mcpManager, &token); err != nil {
						log.Printf("Reconnection failed: %v. Retrying in %v...", err, reconnectDelay)
						continue
					}
					log.Println("Successfully reconnected to MCP server")
				}
				continue
			}
			handleNotification(agent, event)
		}
	}
}

// reconnectMCP attempts to reconnect to the MCP server
func reconnectMCP(cfg *Config, mcpManager *MCPManager, token *string) error {
	// Close existing connection
	mcpManager.Close()

	// Re-authenticate
	newToken, err := login(cfg.ARPURL, cfg.ARPUsername, cfg.ARPPassword)
	if err != nil {
		return fmt.Errorf("failed to re-authenticate: %w", err)
	}
	*token = newToken

	// Create new MCP client
	mcpClient := NewMCPClient(cfg.ARPURL, newToken)
	if err := mcpClient.Connect(); err != nil {
		return fmt.Errorf("failed to reconnect to MCP: %w", err)
	}

	// Initialize MCP
	if _, err := mcpClient.Initialize(); err != nil {
		mcpClient.Close()
		return fmt.Errorf("failed to initialize MCP on reconnect: %w", err)
	}

	// Note: We can't easily replace the mcpManager's internal client
	// This is a limitation - in a production system we'd need to refactor
	// the MCPManager to support reconnection
	log.Println("MCP reconnection requires agent restart - please restart the agent")
	return fmt.Errorf("MCP reconnection requires agent restart")
}

// login authenticates with the ARP server and returns a JWT token
func login(baseURL, username, password string) (string, error) {
	// Ensure URL has the /query endpoint
	loginURL := strings.TrimSuffix(baseURL, "/")
	if !strings.HasSuffix(loginURL, "/query") {
		loginURL = loginURL + "/query"
	}

	query := `
		mutation Login($email: String!, $password: String!) {
			login(email: $email, password: $password) {
				token
				user {
					id
					email
				}
			}
		}`

	reqBody := map[string]interface{}{
		"query": query,
		"variables": map[string]interface{}{
			"email":    username,
			"password": password,
		},
	}

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

	req, err := http.NewRequest("POST", loginURL, bytes.NewReader(bodyBytes))
	if err != nil {
		return "", fmt.Errorf("failed to create request: %w", err)
	}

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

	client := &http.Client{Timeout: 30 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return "", fmt.Errorf("request failed: %w", err)
	}
	defer resp.Body.Close()

	var result struct {
		Data struct {
			Login struct {
				Token string `json:"token"`
				User  struct {
					ID    string `json:"id"`
					Email string `json:"email"`
				} `json:"user"`
			} `json:"login"`
		} `json:"data"`
		Errors []struct {
			Message string `json:"message"`
		} `json:"errors"`
	}

	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return "", fmt.Errorf("failed to parse response: %w", err)
	}

	if len(result.Errors) > 0 {
		return "", fmt.Errorf("login failed: %s", result.Errors[0].Message)
	}

	if result.Data.Login.Token == "" {
		return "", fmt.Errorf("no token received")
	}

	return result.Data.Login.Token, nil
}

// resourceURIs extracts URIs from resources for logging
func resourceURIs(resources []Resource) []string {
	uris := make([]string, len(resources))
	for i, r := range resources {
		uris[i] = r.URI
	}
	return uris
}

// handleNotification processes an MCP notification and queues it for processing
func handleNotification(agent *Agent, event json.RawMessage) {
	// Parse the notification
	var notification JSONRPCNotification
	if err := json.Unmarshal(event, &notification); err != nil {
		log.Printf("Failed to parse notification: %v", err)
		return
	}

	// Handle resource update notifications
	if notification.Method == "notifications/resources/updated" {
		params, ok := notification.Params.(map[string]interface{})
		if !ok {
			log.Printf("Invalid notification params")
			return
		}

		uri, _ := params["uri"].(string)
		contents, ok := params["contents"].(map[string]interface{})
		if !ok {
			log.Printf("Invalid notification contents")
			return
		}

		text, _ := contents["text"].(string)
		log.Printf("Received event from %s", uri)

		// Queue the event for processing (non-blocking)
		agent.QueueEvent(uri, json.RawMessage(text))
	}
}