package server

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"path/filepath"
	"strings"
	"time"

	gonostr "github.com/nbd-wtf/go-nostr"

	"gitcitadel-online/internal/cache"
	"gitcitadel-online/internal/generator"
	"gitcitadel-online/internal/logger"
	"gitcitadel-online/internal/nostr"
)

// setupRoutes sets up all HTTP routes
func (s *Server) setupRoutes(mux *http.ServeMux) {
	// Static files
	mux.HandleFunc("/static/", s.handleStatic)

	// Media cache
	mux.HandleFunc("/cache/media/", s.handleMediaCache)

	// Favicon
	mux.HandleFunc("/favicon.ico", s.handleFavicon)

	// Main routes
	mux.HandleFunc("/", s.handleLanding)
	mux.HandleFunc("/wiki/", s.handleWiki)
	mux.HandleFunc("/blog", s.handleBlog)
	mux.HandleFunc("/articles", s.handleArticles)
	mux.HandleFunc("/ebooks", s.handleEBooks)
	mux.HandleFunc("/contact", s.handleContact)
	mux.HandleFunc("/feed", s.handleFeed)

	// Health and metrics
	mux.HandleFunc("/health", s.handleHealth)
	mux.HandleFunc("/metrics", s.handleMetrics)

	// SEO
	mux.HandleFunc("/sitemap.xml", s.handleSitemap)
	mux.HandleFunc("/robots.txt", s.handleRobots)

	// API endpoints
	mux.HandleFunc("/api/contact", s.handleContactAPI)
}

// handleLanding handles the landing page
func (s *Server) handleLanding(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		s.handle404(w, r)
		return
	}

	page, exists := s.cache.Get("/")
	if !exists {
		http.Error(w, "Page not ready", http.StatusServiceUnavailable)
		return
	}

	s.servePage(w, r, page)
}

// handleWiki handles wiki article pages and wiki index
func (s *Server) handleWiki(w http.ResponseWriter, r *http.Request) {
	path := r.URL.Path

	// Handle wiki index page (/wiki or /wiki/)
	if path == "/wiki" || path == "/wiki/" {
		page, exists := s.cache.Get("/wiki")
		if !exists {
			http.Error(w, "Page not ready", http.StatusServiceUnavailable)
			return
		}
		s.servePage(w, r, page)
		return
	}

	// Handle individual wiki pages (/wiki/{dTag})
	page, exists := s.cache.Get(path)
	if !exists {
		s.handle404(w, r)
		return
	}

	s.servePage(w, r, page)
}

// handleBlog handles the blog page
func (s *Server) handleBlog(w http.ResponseWriter, r *http.Request) {
	page, exists := s.cache.Get("/blog")
	if !exists {
		http.Error(w, "Page not ready", http.StatusServiceUnavailable)
		return
	}

	s.servePage(w, r, page)
}

// handleArticles handles the articles page
func (s *Server) handleArticles(w http.ResponseWriter, r *http.Request) {
	page, exists := s.cache.Get("/articles")
	if !exists {
		http.Error(w, "Page not ready", http.StatusServiceUnavailable)
		return
	}

	s.servePage(w, r, page)
}

// handleEBooks handles the e-books listing page
func (s *Server) handleEBooks(w http.ResponseWriter, r *http.Request) {
	page, exists := s.cache.Get("/ebooks")
	if !exists {
		http.Error(w, "Page not ready", http.StatusServiceUnavailable)
		return
	}

	s.servePage(w, r, page)
}

// handleFeed handles the Feed page
func (s *Server) handleFeed(w http.ResponseWriter, r *http.Request) {
	page, exists := s.cache.Get("/feed")
	if !exists {
		http.Error(w, "Page not ready", http.StatusServiceUnavailable)
		return
	}

	s.servePage(w, r, page)
}

// handleContact handles the contact form (GET and POST)
func (s *Server) handleContact(w http.ResponseWriter, r *http.Request) {
	if r.Method == http.MethodGet {
		// Fetch repo announcement for embedding in page
		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()

		var repoAnnouncement *nostr.RepoAnnouncement
		var err error
		if s.repoAnnouncement != "" {
			repoAnnouncement, err = s.issueService.FetchRepoAnnouncement(ctx, s.repoAnnouncement)
			if err != nil {
				logger.Warnf("Failed to fetch repo announcement for contact page: %v", err)
				// Continue without repo announcement - form will show error
			}
		}

		// Fetch profile for npub
		var profile *nostr.Profile
		npub := "npub1s3ht77dq4zqnya8vjun5jp3p44pr794ru36d0ltxu65chljw8xjqd975wz"
		if s.nostrClient != nil {
			profile, err = s.nostrClient.FetchProfile(ctx, npub)
			if err != nil {
				logger.Warnf("Failed to fetch profile for contact page: %v", err)
				// Continue without profile - not critical
			}
		}

		// Render the contact form (feed items not needed - only on landing page)
		html, err := s.htmlGenerator.GenerateContactPage(false, "", "", nil, repoAnnouncement, []generator.FeedItemInfo{}, profile)
		if err != nil {
			http.Error(w, "Failed to generate contact page", http.StatusInternalServerError)
			return
		}
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		w.Write([]byte(html))
		return
	}

	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	// Parse form data
	if err := r.ParseForm(); err != nil {
		html, _ := s.htmlGenerator.GenerateContactPage(false, "Failed to parse form data", "", nil, nil, []generator.FeedItemInfo{}, nil)
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		w.Write([]byte(html))
		return
	}

	subject := strings.TrimSpace(r.FormValue("subject"))
	content := strings.TrimSpace(r.FormValue("content"))
	labelsStr := strings.TrimSpace(r.FormValue("labels"))

	// Validate required fields
	if subject == "" || content == "" {
		formData := map[string]string{
			"subject": subject,
			"content": content,
			"labels":  labelsStr,
		}
		html, _ := s.htmlGenerator.GenerateContactPage(false, "Subject and message are required", "", formData, nil, []generator.FeedItemInfo{}, nil)
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		w.Write([]byte(html))
		return
	}

	// Parse labels
	var labels []string
	if labelsStr != "" {
		labelParts := strings.Split(labelsStr, ",")
		for _, label := range labelParts {
			label = strings.TrimSpace(label)
			if label != "" {
				labels = append(labels, label)
			}
		}
	}

	// Fetch repo announcement
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	repoAnnouncement, err := s.issueService.FetchRepoAnnouncement(ctx, s.repoAnnouncement)
	if err != nil {
		logger.Errorf("Failed to fetch repo announcement: %v", err)
		formData := map[string]string{
			"subject": subject,
			"content": content,
			"labels":  labelsStr,
		}
		html, _ := s.htmlGenerator.GenerateContactPage(false, "Failed to connect to repository. Please try again later.", "", formData, nil, []generator.FeedItemInfo{}, nil)
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		w.Write([]byte(html))
		return
	}

	// Create issue request
	issueReq := &nostr.IssueRequest{
		Subject: subject,
		Content: content,
		Labels:  labels,
	}

	// Publish issue (using anonymous key - server generates random key)
	eventID, err := s.issueService.PublishIssue(ctx, repoAnnouncement, issueReq, "")
	if err != nil {
		logger.Errorf("Failed to publish issue: %v", err)
		formData := map[string]string{
			"subject": subject,
			"content": content,
			"labels":  labelsStr,
		}
		html, _ := s.htmlGenerator.GenerateContactPage(false, "Failed to submit your message. Please try again later.", "", formData, nil, []generator.FeedItemInfo{}, nil)
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		w.Write([]byte(html))
		return
	}

	// Success - render success page
	html, err := s.htmlGenerator.GenerateContactPage(true, "", eventID, nil, repoAnnouncement, []generator.FeedItemInfo{}, nil)
	if err != nil {
		http.Error(w, "Failed to generate success page", http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.Write([]byte(html))
}

// handleContactAPI handles API requests for contact form with browser-signed events
func (s *Server) handleContactAPI(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	// Parse JSON request
	var req struct {
		Event            *gonostr.Event `json:"event"`
		AdditionalRelays []string       `json:"additionalRelays,omitempty"`
	}

	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, fmt.Sprintf("Invalid JSON: %v", err), http.StatusBadRequest)
		return
	}

	if req.Event == nil {
		http.Error(w, "Event is required", http.StatusBadRequest)
		return
	}

	// Validate event kind (should be kind 1621 for issues per NIP-34)
	if req.Event.Kind != 1621 {
		http.Error(w, fmt.Sprintf("Invalid event kind: expected 1621, got %d", req.Event.Kind), http.StatusBadRequest)
		return
	}

	// Verify the event signature
	valid, err := req.Event.CheckSignature()
	if err != nil {
		http.Error(w, fmt.Sprintf("Failed to check signature: %v", err), http.StatusBadRequest)
		return
	}
	if !valid {
		http.Error(w, "Invalid event signature", http.StatusBadRequest)
		return
	}

	// Publish the signed event to contact relays
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	// Get contact relays
	contactRelays := s.nostrClient.GetContactRelays()

	// Combine contact relays with user's outbox relays (if provided)
	allRelays := make(map[string]bool)
	for _, relay := range contactRelays {
		allRelays[relay] = true
	}
	// Add user's outbox relays (from their kind 10002 relay list)
	for _, relay := range req.AdditionalRelays {
		if relay != "" {
			allRelays[relay] = true
		}
	}

	// Convert map to slice
	relaysToPublish := make([]string, 0, len(allRelays))
	for relay := range allRelays {
		relaysToPublish = append(relaysToPublish, relay)
	}

	// Publish to all relays (contact relays + user outbox relays)
	var lastErr error
	var published bool
	for _, relayURL := range relaysToPublish {
		relay, err := s.nostrClient.ConnectToRelay(ctx, relayURL)
		if err != nil {
			logger.WithFields(map[string]interface{}{
				"relay": relayURL,
				"error": err,
			}).Warn("Failed to connect to contact relay")
			lastErr = err
			continue
		}

		err = relay.Publish(ctx, *req.Event)
		relay.Close()

		if err != nil {
			logger.WithFields(map[string]interface{}{
				"relay": relayURL,
				"error": err,
			}).Warn("Failed to publish to contact relay")
			lastErr = err
		} else {
			published = true
			logger.WithFields(map[string]interface{}{
				"relay":    relayURL,
				"event_id": req.Event.ID,
			}).Info("Published contact event to relay")
		}
	}

	if !published {
		logger.Errorf("Failed to publish contact event to any relay: %v", lastErr)
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprintf(w, `{"error": "Failed to publish to any relay: %s"}`, lastErr.Error())
		return
	}

	// Return success response
	w.Header().Set("Content-Type", "application/json")
	fmt.Fprintf(w, `{"success": true, "event_id": "%s"}`, req.Event.ID)
}

// handleStatic serves static files
func (s *Server) handleStatic(w http.ResponseWriter, r *http.Request) {
	// Serve static files from the static directory
	http.StripPrefix("/static/", http.FileServer(http.Dir("./static"))).ServeHTTP(w, r)
}

// handleFavicon serves the favicon
func (s *Server) handleFavicon(w http.ResponseWriter, r *http.Request) {
	// Serve the SVG icon as favicon
	http.ServeFile(w, r, "./static/GitCitadel_Icon_Black.svg")
}

// handleMediaCache serves cached media files
func (s *Server) handleMediaCache(w http.ResponseWriter, r *http.Request) {
	if s.mediaCache == nil {
		http.Error(w, "Media cache not available", http.StatusServiceUnavailable)
		return
	}

	// Extract filename from path
	filename := r.URL.Path[len("/cache/media/"):]
	if filename == "" {
		http.Error(w, "Invalid path", http.StatusBadRequest)
		return
	}

	// Serve file from cache directory
	cachePath := filepath.Join(s.mediaCache.GetCacheDir(), filename)
	http.ServeFile(w, r, cachePath)
}

// handleHealth handles health check requests
func (s *Server) handleHealth(w http.ResponseWriter, r *http.Request) {
	if s.cache.Size() == 0 {
		w.WriteHeader(http.StatusServiceUnavailable)
		w.Write([]byte("Not ready"))
		return
	}
	w.WriteHeader(http.StatusOK)
	w.Write([]byte("OK"))
}

// handleMetrics handles metrics requests
func (s *Server) handleMetrics(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "text/plain")
	fmt.Fprintf(w, "cache_size %d\n", s.cache.Size())
	fmt.Fprintf(w, "feed_items %d\n", len(s.feedCache.Get()))
}

// handleSitemap handles sitemap requests
func (s *Server) handleSitemap(w http.ResponseWriter, r *http.Request) {
	// TODO: Generate sitemap from cache
	w.Header().Set("Content-Type", "application/xml")
	w.Write([]byte(`<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
</urlset>`))
}

// handleRobots handles robots.txt requests
func (s *Server) handleRobots(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "text/plain")
	w.Write([]byte("User-agent: *\nAllow: /\nSitemap: /sitemap.xml\n"))
}

// handle404 handles 404 errors
func (s *Server) handle404(w http.ResponseWriter, _ *http.Request) {
	w.WriteHeader(http.StatusNotFound)
	html, err := s.htmlGenerator.GenerateErrorPage(404, []generator.FeedItemInfo{})
	if err != nil {
		w.Write([]byte("404 - Page Not Found"))
		return
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.Write([]byte(html))
}

// servePage serves a cached page with proper headers
func (s *Server) servePage(w http.ResponseWriter, r *http.Request, page *cache.CachedPage) {
	// Set headers
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.Header().Set("ETag", page.ETag)
	w.Header().Set("Cache-Control", "public, max-age=3600")
	w.Header().Set("Last-Modified", page.LastUpdated.Format(http.TimeFormat))

	// Check If-None-Match for conditional requests
	if match := r.Header.Get("If-None-Match"); match == page.ETag {
		w.WriteHeader(http.StatusNotModified)
		return
	}

	// Check Accept-Encoding for compression
	acceptEncoding := r.Header.Get("Accept-Encoding")
	if strings.Contains(acceptEncoding, "gzip") && len(page.Compressed) > 0 {
		w.Header().Set("Content-Encoding", "gzip")
		w.Header().Set("Vary", "Accept-Encoding")
		w.Write(page.Compressed)
		return
	}

	// Serve uncompressed
	w.Write([]byte(page.Content))
}

// middleware adds security headers and logging
func (s *Server) middleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Security headers
		w.Header().Set("X-Content-Type-Options", "nosniff")
		w.Header().Set("X-Frame-Options", "DENY")
		w.Header().Set("X-XSS-Protection", "1; mode=block")
		w.Header().Set("Referrer-Policy", "strict-origin-when-cross-origin")

		// CSP header - allow unpkg.com for Lucide icons and jsdelivr.net for nostr-tools
		w.Header().Set("Content-Security-Policy", "default-src 'self'; script-src 'self' 'unsafe-inline' https://unpkg.com https://cdn.jsdelivr.net; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self' data:;")

		// Log request (only in debug mode to reduce noise)
		start := time.Now()
		next.ServeHTTP(w, r)
		logger.WithFields(map[string]interface{}{
			"method":   r.Method,
			"path":     r.URL.Path,
			"duration": time.Since(start),
		}).Debug("HTTP request")
	})
}