package handler

import (
	"embed"
	"encoding/json"
	"io/fs"
	"net/http"

	"teraclone/internal/service"

	"github.com/gorilla/websocket"
)

//go:embed web/*
var webFiles embed.FS

type AppHandler struct {
	appService *service.AppService
	fileServer http.Handler
}

type socketRequest struct {
	Type string `json:"type"`
	Data string `json:"data"`
}

type socketResponse struct {
	Type       string `json:"type"`
	Data       string `json:"data,omitempty"`
	Prompt     string `json:"prompt,omitempty"`
	WorkingDir string `json:"workingDir,omitempty"`
}

var upgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

func NewAppHandler(appService *service.AppService) *AppHandler {
	webRoot, err := fs.Sub(webFiles, "web")

	if err != nil {
		panic(err)
	}

	return &AppHandler{
		appService: appService,
		fileServer: http.FileServer(http.FS(webRoot)),
	}
}

func (h *AppHandler) RegisterRoutes(mux *http.ServeMux) {
	mux.HandleFunc("/", h.handleRoot)
	mux.HandleFunc("/health", h.handleHealth)
	mux.HandleFunc("/ws", h.handleWebSocket)
	mux.Handle("/assets/", http.StripPrefix("/assets/", h.fileServer))
}

func (h *AppHandler) RegisterLegacyRoutes(mux *http.ServeMux) {
	mux.HandleFunc("/legacy", h.handleLegacyRoot)
	mux.HandleFunc("/legacy/", h.handleLegacyRoot)
	mux.HandleFunc("/legacy/ws", h.handleLegacyWebSocket)
	mux.Handle("/legacy/assets/", http.StripPrefix("/legacy/assets/", h.fileServer))
}

func (h *AppHandler) HandleHealth(w http.ResponseWriter, r *http.Request) {
	h.handleHealth(w, r)
}

func (h *AppHandler) handleRoot(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		http.NotFound(w, r)
		return
	}

	http.ServeFileFS(w, r, webFiles, "web/index.html")
}

func (h *AppHandler) handleHealth(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	response := map[string]string{
		"status": h.appService.HealthStatus(),
	}

	_ = json.NewEncoder(w).Encode(response)
}

func (h *AppHandler) handleLegacyRoot(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/legacy" && r.URL.Path != "/legacy/" {
		http.NotFound(w, r)
		return
	}

	http.ServeFileFS(w, r, webFiles, "web/index.html")
}

func (h *AppHandler) handleLegacyWebSocket(w http.ResponseWriter, r *http.Request) {
	h.handleWebSocket(w, r)
}

func (h *AppHandler) handleWebSocket(w http.ResponseWriter, r *http.Request) {
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		return
	}
	defer conn.Close()

	session, err := h.appService.NewTerminalSession()
	if err != nil {
		_ = conn.WriteJSON(socketResponse{
			Type: "error",
			Data: err.Error(),
		})
		return
	}

	_ = conn.WriteJSON(socketResponse{
		Type:       "welcome",
		Data:       session.WelcomeMessage(),
		Prompt:     session.Prompt(),
		WorkingDir: session.Snapshot().WorkingDir,
	})

	for {
		var request socketRequest
		if err := conn.ReadJSON(&request); err != nil {
			return
		}

		if request.Type != "input" {
			continue
		}

		result := session.Execute(request.Data)
		_ = conn.WriteJSON(socketResponse{
			Type:       "output",
			Data:       result.Output,
			Prompt:     result.Prompt,
			WorkingDir: result.WorkingDir,
		})
	}
}