package web

import (
	"bufio"
	"context"
	"embed"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"rmm-hunter/internal/suspicious"
	"strings"
	"sync"
	"time"

	"rmm-hunter/internal/pkg"
	"rmm-hunter/internal/pkg/hunt/eliminate"
	"rmm-hunter/internal/pkg/hunter"

	"github.com/gorilla/websocket"
)

//go:embed templates/*
var contentFS embed.FS

// broadcaster for hunt logs
type wsHub struct {
	mu    sync.Mutex
	conns map[*websocket.Conn]struct{}
}

func newHub() *wsHub                   { return &wsHub{conns: make(map[*websocket.Conn]struct{})} }
func (h *wsHub) add(c *websocket.Conn) { h.mu.Lock(); h.conns[c] = struct{}{}; h.mu.Unlock() }
func (h *wsHub) rm(c *websocket.Conn)  { h.mu.Lock(); delete(h.conns, c); h.mu.Unlock() }
func (h *wsHub) send(msg string) {
	h.mu.Lock()
	for c := range h.conns {
		_ = c.WriteMessage(websocket.TextMessage, []byte(msg))
	}
	h.mu.Unlock()
}

// JSONReportMeta is a lightweight descriptor for previous hunts
type JSONReportMeta struct {
	File        string `json:"file"`
	ReportName  string `json:"reportName"`
	GeneratedAt string `json:"generatedAt"`
}

type server struct {
	hub    *wsHub
	http   *http.Server
	quitCh chan struct{}
}

func StartWebServer() {
	var hostAdded bool
	h := newHub()
	s := &server{hub: h, quitCh: make(chan struct{})}

	// Add hosts file entry for rmm-hunter
	if err := AddHostsEntry(); err != nil {
		log.Printf("[web] Warning: Failed to add hosts entry: %v\n", err)
	} else {
		hostAdded = true
	}

	mux := http.NewServeMux()
	mux.HandleFunc("/", s.handleIndex)
	mux.HandleFunc("/logo", s.handleLogo)
	mux.HandleFunc("/favicon.ico", s.handleFavicon)
	mux.HandleFunc("/favicon-32x32.png", s.handleFavicon)
	mux.HandleFunc("/favicon-16x16.png", s.handleFavicon)
	mux.HandleFunc("/apple-touch-icon.png", s.handleFavicon)
	mux.HandleFunc("/site.webmanifest", s.handleManifest)
	mux.HandleFunc("/api/hunts", s.handleListHunts)
	mux.HandleFunc("/api/hunt/start", s.handleStartHunt)
	mux.HandleFunc("/api/report", s.handleGetReport)
	mux.HandleFunc("/api/eliminate", s.handleEliminate)
	mux.HandleFunc("/api/quit", s.handleQuit)
	mux.HandleFunc("/ws/hunt", s.handleWS)

	s.http = &http.Server{Addr: ":80", Handler: logRequests(mux)}

	// Determine which URL to open in browser
	browserURL := "http://rmm-hunter"
	if !hostAdded {
		browserURL = "http://127.0.0.1"
	}

	// Channel to signal when server is ready
	serverReady := make(chan struct{})

	go func() {
		// Signal that we're about to start listening
		close(serverReady)

		if err := s.http.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatalf("listen: %v", err)
		}
	}()

	// Wait for server to start, then open browser
	<-serverReady
	time.Sleep(500 * time.Millisecond) // Give server a moment to fully initialize
	log.Printf("[web] Opening browser to %s...\n", browserURL)
	_, err := OpenBrowser(browserURL)
	if err != nil {
		log.Printf("[web] Warning: Failed to open browser: %v\n", err)
		if !hostAdded {
			log.Printf("[web] Please open your browser and navigate to http://127.0.0.1\n")
		}
		log.Printf("[web] Please open your browser and navigate to http://rmm-hunter\n")
	}

	// block until quit
	<-s.quitCh

	// Clean up hosts entry on exit
	log.Printf("[web] Cleaning up hosts entry...\n")
	if err := RemoveHostsEntry(); err != nil {
		log.Printf("[web] Warning: Failed to remove hosts entry: %v\n", err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()
	_ = s.http.Shutdown(ctx)
	os.Exit(0)
}

func logRequests(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		log.Printf("%s %s", r.Method, r.URL.Path)
		next.ServeHTTP(w, r)
	})
}

func (s *server) handleIndex(w http.ResponseWriter, r *http.Request) {
	b, err := contentFS.ReadFile("templates/index.html")
	if err != nil {
		http.Error(w, "template missing", 500)
		return
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	_, _ = w.Write(b)
}

// serve logo from repo .img; fallback to 404
func (s *server) handleLogo(w http.ResponseWriter, r *http.Request) {
	path := filepath.Join(".img", "rmm-hunter.png")
	f, err := os.Open(path)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	defer f.Close()
	w.Header().Set("Content-Type", "image/png")
	http.ServeContent(w, r, "rmm-hunter.png", time.Now(), f)
}

// serve favicon files from embedded templates folder
func (s *server) handleFavicon(w http.ResponseWriter, r *http.Request) {
	filename := filepath.Base(r.URL.Path)
	b, err := contentFS.ReadFile("templates/" + filename)
	if err != nil {
		http.NotFound(w, r)
		return
	}

	// Set appropriate content type
	contentType := "image/x-icon"
	if filepath.Ext(filename) == ".png" {
		contentType = "image/png"
	}

	w.Header().Set("Content-Type", contentType)
	w.Header().Set("Cache-Control", "public, max-age=31536000")
	w.Write(b)
}

// serve site.webmanifest from embedded templates folder
func (s *server) handleManifest(w http.ResponseWriter, r *http.Request) {
	b, err := contentFS.ReadFile("templates/site.webmanifest")
	if err != nil {
		http.NotFound(w, r)
		return
	}
	w.Header().Set("Content-Type", "application/manifest+json")
	w.Header().Set("Cache-Control", "public, max-age=31536000")
	w.Write(b)
}

func (s *server) handleListHunts(w http.ResponseWriter, r *http.Request) {
	files, _ := filepath.Glob("*.json")
	var out []JSONReportMeta
	for _, f := range files {
		// read small head of file to verify
		b, err := os.ReadFile(f)
		if err != nil {
			continue
		}
		var env struct {
			ReportName  string `json:"reportName"`
			GeneratedAt string `json:"generatedAt"`
		}
		if json.Unmarshal(b, &env) == nil && (env.ReportName != "" || strings.Contains(string(b), "\"findings\"")) {
			out = append(out, JSONReportMeta{File: f, ReportName: env.ReportName, GeneratedAt: env.GeneratedAt})
		}
	}
	w.Header().Set("Content-Type", "application/json")
	_ = json.NewEncoder(w).Encode(out)
}

func (s *server) handleGetReport(w http.ResponseWriter, r *http.Request) {
	f := r.URL.Query().Get("file")
	if f == "" || strings.Contains(f, "..") {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusBadRequest)
		json.NewEncoder(w).Encode(map[string]string{"error": "bad file"})
		return
	}
	b, err := os.ReadFile(f)
	if err != nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusNotFound)
		json.NewEncoder(w).Encode(map[string]string{"error": "not found"})
		return
	}
	w.Header().Set("Content-Type", "application/json")
	w.Write(b)
}

func (s *server) handleStartHunt(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusMethodNotAllowed)
		json.NewEncoder(w).Encode(map[string]string{"error": "use POST"})
		return
	}
	name := fmt.Sprintf("hunt-%s", time.Now().Format("20060102-150405"))
	go s.runHunt(name)
	w.Header().Set("Content-Type", "application/json")
	_ = json.NewEncoder(w).Encode(map[string]string{"reportName": name})
}

func (s *server) runHunt(name string) {
	// redirect stdout to our pipe
	oldStdout := os.Stdout
	pr, pw, _ := os.Pipe()
	os.Stdout = pw
	// also mirror stderr
	oldStderr := os.Stderr
	pr2, pw2, _ := os.Pipe()
	os.Stderr = pw2

	// reader goroutines
	done := make(chan struct{})
	go func() {
		sc := bufio.NewScanner(pr)
		for sc.Scan() {
			s.hub.send(sc.Text())
		}
		done <- struct{}{}
	}()
	go func() {
		sc := bufio.NewScanner(pr2)
		for sc.Scan() {
			s.hub.send(sc.Text())
		}
		done <- struct{}{}
	}()

	// run hunter
	hunter.Start(pkg.RunOptions{Name: name})

	// close writers and restore
	_ = pw.Close()
	_ = pw2.Close()
	<-done
	<-done
	os.Stdout = oldStdout
	os.Stderr = oldStderr
	s.hub.send("[+] Hunt complete")
}

func (s *server) handleWS(w http.ResponseWriter, r *http.Request) {
	up := websocket.Upgrader{CheckOrigin: func(r *http.Request) bool { return true }}
	c, err := up.Upgrade(w, r, nil)
	if err != nil {
		return
	}
	s.hub.add(c)
	defer func() { s.hub.rm(c); _ = c.Close() }()
	for { // keep alive until client closes
		if _, _, err := c.ReadMessage(); err != nil {
			return
		}
	}
}

func (s *server) handleEliminate(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusMethodNotAllowed)
		json.NewEncoder(w).Encode(map[string]string{"error": "method not allowed"})
		return
	}

	var req struct {
		ReportFile string `json:"reportFile"`
		Type       string `json:"type"`
		Index      int    `json:"index"`
	}

	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusBadRequest)
		json.NewEncoder(w).Encode(map[string]string{"error": "invalid request"})
		return
	}

	// Load the report file
	reportFile := req.ReportFile
	if !strings.HasSuffix(reportFile, ".json") {
		reportFile += ".json"
	}
	reportPath := filepath.Join(".", reportFile)
	data, err := os.ReadFile(reportPath)
	if err != nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(map[string]string{"error": fmt.Sprintf("failed to read report: %v", err)})
		return
	}

	// Parse the full report structure with findings wrapper
	var fullReport struct {
		ReportName  string                `json:"reportName"`
		GeneratedAt string                `json:"generatedAt"`
		RiskRating  interface{}           `json:"riskRating"`
		Findings    suspicious.Suspicious `json:"findings"`
	}
	if err := json.Unmarshal(data, &fullReport); err != nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(map[string]string{"error": fmt.Sprintf("failed to parse report: %v", err)})
		return
	}

	// Perform elimination based on type
	if err := performElimination(&fullReport.Findings, req.Type, req.Index); err != nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusBadRequest)
		json.NewEncoder(w).Encode(map[string]string{"error": err.Error()})
		return
	}

	// Save updated report
	updatedData, err := json.MarshalIndent(fullReport, "", "  ")
	if err != nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(map[string]string{"error": fmt.Sprintf("failed to marshal report: %v", err)})
		return
	}

	if err := os.WriteFile(reportPath, updatedData, 0644); err != nil {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(map[string]string{"error": fmt.Sprintf("failed to save report: %v", err)})
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]string{"status": "success"})
}

func (s *server) handleQuit(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusMethodNotAllowed)
		json.NewEncoder(w).Encode(map[string]string{"error": "use POST"})
		return
	}
	w.Header().Set("Content-Type", "application/json")
	_, _ = w.Write([]byte(`{"ok":true}`))
	go func() { time.Sleep(200 * time.Millisecond); s.quitCh <- struct{}{} }()
}

// performElimination executes the elimination logic for a specific finding type and index
func performElimination(report *suspicious.Suspicious, typeKey string, idx int) error {
	switch typeKey {
	case "connections":
		if idx < 0 || idx >= len(report.OutboundConnections) {
			return fmt.Errorf("invalid index: %d (array length: %d)", idx, len(report.OutboundConnections))
		}
		conn := report.OutboundConnections[idx]
		if err := eliminate.EliminateConnection(conn.RemoteHost); err != nil {
			return err
		}
		report.OutboundConnections[idx].Eliminated = true

	case "processes":
		if idx < 0 || idx >= len(report.Processes) {
			return fmt.Errorf("invalid index: %d (array length: %d)", idx, len(report.Processes))
		}
		proc := report.Processes[idx]
		if err := eliminate.EliminateProcess(proc); err != nil {
			return err
		}
		report.Processes[idx].Eliminated = true

	case "services":
		if idx < 0 || idx >= len(report.Services) {
			return fmt.Errorf("invalid index: %d (array length: %d)", idx, len(report.Services))
		}
		svc := report.Services[idx]
		if svc == nil {
			return fmt.Errorf("service is nil")
		}
		if err := eliminate.EliminateService(*svc); err != nil {
			return err
		}
		report.Services[idx].Eliminated = true

	case "tasks":
		if idx < 0 || idx >= len(report.ScheduledTasks) {
			return fmt.Errorf("invalid index: %d (array length: %d)", idx, len(report.ScheduledTasks))
		}
		task := report.ScheduledTasks[idx]
		if task == nil {
			return fmt.Errorf("task is nil")
		}
		if err := eliminate.EliminateScheduledTask(*task); err != nil {
			return err
		}
		report.ScheduledTasks[idx].Eliminated = true

	case "autoruns":
		if idx < 0 || idx >= len(report.AutoRuns) {
			return fmt.Errorf("invalid index: %d (array length: %d)", idx, len(report.AutoRuns))
		}
		ar := report.AutoRuns[idx]
		if err := eliminate.EliminateAutoRun(ar); err != nil {
			return err
		}
		report.AutoRuns[idx].Eliminated = true

	case "binaries":
		if idx < 0 || idx >= len(report.Binaries) {
			return fmt.Errorf("invalid index: %d (array length: %d)", idx, len(report.Binaries))
		}
		bin := report.Binaries[idx]
		// Check if binary is blocked by active processes/services
		if err := checkBinaryBlocked(bin.Path, *report); err != nil {
			return err
		}
		if err := eliminate.EliminateBinary(bin.Path); err != nil {
			return err
		}
		report.Binaries[idx].Eliminated = true

	case "directories":
		if idx < 0 || idx >= len(report.Directories) {
			return fmt.Errorf("invalid index: %d (array length: %d)", idx, len(report.Directories))
		}
		dir := report.Directories[idx]
		// Check if directory is blocked by active processes/services
		if err := checkDirectoryBlocked(dir.Path, *report); err != nil {
			return err
		}
		if err := eliminate.EliminateDirectory(dir.Path); err != nil {
			return err
		}
		report.Directories[idx].Eliminated = true

	default:
		return fmt.Errorf("unknown type: %s", typeKey)
	}

	return nil
}

// checkBinaryBlocked checks if a binary is in use by active processes or services
func checkBinaryBlocked(path string, data suspicious.Suspicious) error {
	normPath := func(p string) string {
		return strings.ToLower(filepath.Clean(p))
	}

	np := normPath(path)

	// Check active processes
	for _, p := range data.Processes {
		if p.Eliminated {
			continue
		}
		if normPath(p.Path) == np {
			return fmt.Errorf("binary in use by running process %s (PID %d). Eliminate the process first", p.Name, p.PID)
		}
	}

	// Check enabled services
	for _, s := range data.Services {
		if s == nil || s.Eliminated {
			continue
		}
		sp := normPath(s.BinaryPathName)
		if sp == np && !strings.EqualFold(strings.TrimSpace(s.StartType), "disabled") {
			// Check if service has a running process
			for _, p := range data.Processes {
				if p.Eliminated {
					continue
				}
				if normPath(p.Path) == sp {
					return fmt.Errorf("binary used by active and enabled service %s. Stop/delete the service first", s.Name)
				}
			}
		}
	}

	return nil
}

// checkDirectoryBlocked checks if a directory contains binaries used by active processes or services
func checkDirectoryBlocked(dir string, data suspicious.Suspicious) error {
	normPath := func(p string) string {
		return strings.ToLower(filepath.Clean(p))
	}

	dn := normPath(dir)
	if !strings.HasSuffix(dn, string(filepath.Separator)) {
		dn += string(filepath.Separator)
	}

	inDir := func(p string) bool {
		pp := normPath(p)
		if pp == "" {
			return false
		}
		return strings.HasPrefix(pp, dn)
	}

	// Check processes
	for _, p := range data.Processes {
		if p.Eliminated {
			continue
		}
		if inDir(p.Path) {
			return fmt.Errorf("directory contains active process %s (PID %d). Eliminate the process first", p.Name, p.PID)
		}
	}

	// Check services
	for _, s := range data.Services {
		if s == nil || s.Eliminated {
			continue
		}
		if inDir(s.BinaryPathName) && !strings.EqualFold(strings.TrimSpace(s.StartType), "disabled") {
			// Check if service has a running process
			for _, p := range data.Processes {
				if p.Eliminated {
					continue
				}
				if normPath(p.Path) == normPath(s.BinaryPathName) {
					return fmt.Errorf("directory contains active and enabled service binary for %s. Stop/delete the service first", s.Name)
				}
			}
		}
	}

	return nil
}