package sipguardian

import (
	"encoding/json"
	"net/http"
	"strings"

	"github.com/caddyserver/caddy/v2"
	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
)

func init() {
	caddy.RegisterModule(AdminHandler{})
}

// AdminHandler provides HTTP endpoints to manage SIP Guardian
type AdminHandler struct {
	guardian *SIPGuardian
}

func (AdminHandler) CaddyModule() caddy.ModuleInfo {
	return caddy.ModuleInfo{
		ID:  "http.handlers.sip_guardian_admin",
		New: func() caddy.Module { return new(AdminHandler) },
	}
}

func (h *AdminHandler) Provision(ctx caddy.Context) error {
	// Get the shared guardian instance
	// In production, this would use proper module loading
	h.guardian = &SIPGuardian{}
	return h.guardian.Provision(ctx)
}

// ServeHTTP handles admin API requests
func (h *AdminHandler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
	// Route based on path
	path := r.URL.Path

	switch {
	case strings.HasSuffix(path, "/bans"):
		return h.handleBans(w, r)
	case strings.HasSuffix(path, "/stats"):
		return h.handleStats(w, r)
	case strings.Contains(path, "/unban/"):
		return h.handleUnban(w, r, path)
	case strings.Contains(path, "/ban/"):
		return h.handleBan(w, r, path)
	default:
		return next.ServeHTTP(w, r)
	}
}

// handleBans lists all banned IPs
func (h *AdminHandler) handleBans(w http.ResponseWriter, r *http.Request) error {
	if r.Method != http.MethodGet {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return nil
	}

	bans := h.guardian.GetBannedIPs()

	w.Header().Set("Content-Type", "application/json")
	return json.NewEncoder(w).Encode(map[string]interface{}{
		"bans":  bans,
		"count": len(bans),
	})
}

// handleStats returns current statistics
func (h *AdminHandler) handleStats(w http.ResponseWriter, r *http.Request) error {
	if r.Method != http.MethodGet {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return nil
	}

	stats := h.guardian.GetStats()

	w.Header().Set("Content-Type", "application/json")
	return json.NewEncoder(w).Encode(stats)
}

// handleUnban removes an IP from the ban list
func (h *AdminHandler) handleUnban(w http.ResponseWriter, r *http.Request, path string) error {
	if r.Method != http.MethodPost && r.Method != http.MethodDelete {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return nil
	}

	// Extract IP from path: /admin/sip-guardian/unban/{ip}
	parts := strings.Split(path, "/unban/")
	if len(parts) != 2 || parts[1] == "" {
		http.Error(w, "IP address required", http.StatusBadRequest)
		return nil
	}

	ip := strings.TrimSuffix(parts[1], "/")

	if h.guardian.UnbanIP(ip) {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"success": true,
			"message": "IP unbanned",
			"ip":      ip,
		})
	} else {
		w.WriteHeader(http.StatusNotFound)
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"success": false,
			"message": "IP not found in ban list",
			"ip":      ip,
		})
	}

	return nil
}

// handleBan manually adds an IP to the ban list
func (h *AdminHandler) handleBan(w http.ResponseWriter, r *http.Request, path string) error {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return nil
	}

	// Extract IP from path: /admin/sip-guardian/ban/{ip}
	parts := strings.Split(path, "/ban/")
	if len(parts) != 2 || parts[1] == "" {
		http.Error(w, "IP address required", http.StatusBadRequest)
		return nil
	}

	ip := strings.TrimSuffix(parts[1], "/")

	// Parse optional reason from body
	var body struct {
		Reason string `json:"reason"`
	}
	if r.Body != nil {
		json.NewDecoder(r.Body).Decode(&body)
	}
	if body.Reason == "" {
		body.Reason = "manual_ban"
	}

	// Force a ban by recording max failures
	h.guardian.mu.Lock()
	h.guardian.failureCounts[ip] = &failureTracker{
		count: h.guardian.MaxFailures,
	}
	h.guardian.banIP(ip, body.Reason)
	h.guardian.mu.Unlock()

	w.Header().Set("Content-Type", "application/json")
	return json.NewEncoder(w).Encode(map[string]interface{}{
		"success": true,
		"message": "IP banned",
		"ip":      ip,
		"reason":  body.Reason,
	})
}

// Interface guards
var (
	_ caddyhttp.MiddlewareHandler = (*AdminHandler)(nil)
	_ caddy.Provisioner           = (*AdminHandler)(nil)
)