package agent

import (
	"context"
	"fmt"
	"net/http"
	"time"

	"chorus/internal/config"
	"chorus/internal/logging"
)

// Agent represents a CHORUS agent instance
type Agent struct {
	id     string
	config *config.Config
	logger logging.Logger
	
	// Services
	apiServer *http.Server
	healthServer *http.Server
	
	// P2P components (to be implemented)
	// p2pHost     host.Host
	// dht         *dht.DHT  
	// pubsub      *pubsub.PubSub
}

// New creates a new CHORUS agent
func New(ctx context.Context, cfg *config.Config, logger logging.Logger) (*Agent, error) {
	agent := &Agent{
		id:     cfg.Agent.ID,
		config: cfg,
		logger: logger,
	}
	
	// Initialize HTTP servers
	if err := agent.initHTTPServers(); err != nil {
		return nil, fmt.Errorf("failed to initialize HTTP servers: %w", err)
	}
	
	// TODO: Initialize P2P components
	// TODO: Initialize task coordination
	// TODO: Initialize AI integration
	
	return agent, nil
}

// Start starts all agent services
func (a *Agent) Start() error {
	a.logger.Info("🚀 Starting CHORUS agent services...")
	
	// Start API server
	go func() {
		a.logger.Info("🌐 Starting API server on :%d", a.config.Network.APIPort)
		if err := a.apiServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			a.logger.Error("❌ API server error: %v", err)
		}
	}()
	
	// Start health server
	go func() {
		a.logger.Info("🏥 Starting health server on :%d", a.config.Network.HealthPort)
		if err := a.healthServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			a.logger.Error("❌ Health server error: %v", err)
		}
	}()
	
	// TODO: Start P2P services
	// TODO: Start task coordination
	// TODO: Connect to DHT network
	
	a.logger.Info("✅ All CHORUS agent services started")
	return nil
}

// Stop gracefully stops all agent services
func (a *Agent) Stop(ctx context.Context) error {
	a.logger.Info("🛑 Stopping CHORUS agent services...")
	
	// Stop HTTP servers
	if err := a.apiServer.Shutdown(ctx); err != nil {
		a.logger.Error("⚠️ Error stopping API server: %v", err)
	}
	
	if err := a.healthServer.Shutdown(ctx); err != nil {
		a.logger.Error("⚠️ Error stopping health server: %v", err)
	}
	
	// TODO: Stop P2P services
	// TODO: Stop task coordination
	// TODO: Disconnect from DHT network
	
	a.logger.Info("✅ CHORUS agent services stopped")
	return nil
}

// ID returns the agent ID
func (a *Agent) ID() string {
	return a.id
}

// P2PAddress returns the P2P address (placeholder)
func (a *Agent) P2PAddress() string {
	// TODO: Return actual P2P address when P2P is implemented
	return fmt.Sprintf("/ip4/%s/tcp/%d/p2p/%s", a.config.Network.BindAddr, a.config.Network.P2PPort, a.id)
}

// initHTTPServers initializes the HTTP servers for API and health endpoints
func (a *Agent) initHTTPServers() error {
	// API server
	apiMux := http.NewServeMux()
	apiMux.HandleFunc("/", a.handleRoot)
	apiMux.HandleFunc("/agent/info", a.handleAgentInfo)
	apiMux.HandleFunc("/agent/tasks", a.handleTasks)
	
	a.apiServer = &http.Server{
		Addr:         fmt.Sprintf("%s:%d", a.config.Network.BindAddr, a.config.Network.APIPort),
		Handler:      apiMux,
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 15 * time.Second,
		IdleTimeout:  60 * time.Second,
	}
	
	// Health server
	healthMux := http.NewServeMux()
	healthMux.HandleFunc("/health", a.handleHealth)
	healthMux.HandleFunc("/health/ready", a.handleReady)
	healthMux.HandleFunc("/health/live", a.handleLive)
	
	a.healthServer = &http.Server{
		Addr:         fmt.Sprintf("%s:%d", a.config.Network.BindAddr, a.config.Network.HealthPort),
		Handler:      healthMux,
		ReadTimeout:  5 * time.Second,
		WriteTimeout: 5 * time.Second,
		IdleTimeout:  30 * time.Second,
	}
	
	return nil
}

// HTTP handler implementations

func (a *Agent) handleRoot(w http.ResponseWriter, r *http.Request) {
	response := map[string]interface{}{
		"service": "CHORUS",
		"version": "0.1.0-dev",
		"agent_id": a.id,
		"status": "running",
		"endpoints": map[string]string{
			"agent_info": "/agent/info",
			"tasks": "/agent/tasks",
			"health": fmt.Sprintf("http://localhost:%d/health", a.config.Network.HealthPort),
		},
	}
	
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	
	// Simple JSON response without external dependency
	fmt.Fprintf(w, `{
		"service": "%s",
		"version": "0.1.0-dev",
		"agent_id": "%s",
		"status": "running"
	}`, "CHORUS", a.id)
}

func (a *Agent) handleAgentInfo(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	fmt.Fprintf(w, `{
		"agent_id": "%s",
		"specialization": "%s",
		"max_tasks": %d,
		"capabilities": %q
	}`, a.id, a.config.Agent.Specialization, a.config.Agent.MaxTasks, a.config.Agent.Capabilities)
}

func (a *Agent) handleTasks(w http.ResponseWriter, r *http.Request) {
	// TODO: Implement task management
	w.Header().Set("Content-Type", "application/json")
	fmt.Fprintf(w, `{
		"active_tasks": [],
		"completed_tasks": [],
		"available_for_tasks": true
	}`)
}

func (a *Agent) handleHealth(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	fmt.Fprintf(w, `{
		"status": "healthy",
		"agent_id": "%s",
		"timestamp": "%s",
		"checks": {
			"license": "valid",
			"api_server": "running",
			"p2p": "not_implemented"
		}
	}`, a.id, time.Now().UTC().Format(time.RFC3339))
}

func (a *Agent) handleReady(w http.ResponseWriter, r *http.Request) {
	// Kubernetes readiness probe
	w.WriteHeader(http.StatusOK)
	fmt.Fprint(w, "ready")
}

func (a *Agent) handleLive(w http.ResponseWriter, r *http.Request) {
	// Kubernetes liveness probe
	w.WriteHeader(http.StatusOK)
	fmt.Fprint(w, "live")
}