package handlers

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

	"git.nakama.town/fmartingr/hako/internal/model"
	"git.nakama.town/fmartingr/hako/internal/server/webcontext"
)

// UserHandler handles user administration requests
type UserHandler struct {
	deps model.Dependencies
}

// NewUserHandler creates a new UserHandler
func NewUserHandler(deps model.Dependencies) *UserHandler {
	return &UserHandler{deps: deps}
}

// AdminUserResponse represents a user in admin API responses
type AdminUserResponse struct {
	ID        string `json:"id"`
	Email     string `json:"email"`
	Role      string `json:"role"`
	CreatedAt string `json:"created_at"`
	UpdatedAt string `json:"updated_at"`
}

func userToAdminResponse(u *model.User) AdminUserResponse {
	return AdminUserResponse{
		ID:        u.ID.String(),
		Email:     u.Email,
		Role:      u.Role,
		CreatedAt: u.CreatedAt.Format(time.RFC3339),
		UpdatedAt: u.UpdatedAt.Format(time.RFC3339),
	}
}

// writeJSON writes a JSON response with the given status code
func writeJSON(w http.ResponseWriter, status int, data any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(data)
}

// HandleListUsers handles GET /system/users
func (h *UserHandler) HandleListUsers(w http.ResponseWriter, r *http.Request) {
	users, err := h.deps.Domains().Auth().ListUsers()
	if err != nil {
		http.Error(w, "Failed to list users", http.StatusInternalServerError)
		return
	}

	response := make([]AdminUserResponse, len(users))
	for i, u := range users {
		response[i] = userToAdminResponse(u)
	}

	writeJSON(w, http.StatusOK, response)
}

// CreateUserRequest represents a request to create a user
type CreateUserRequest struct {
	Email    string `json:"email"`
	Password string `json:"password"`
	Role     string `json:"role"`
}

// HandleCreateUser handles POST /system/users
func (h *UserHandler) HandleCreateUser(w http.ResponseWriter, r *http.Request) {
	var req CreateUserRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request body", http.StatusBadRequest)
		return
	}

	if req.Email == "" || req.Password == "" {
		http.Error(w, "Email and password are required", http.StatusBadRequest)
		return
	}

	user, err := h.deps.Domains().Auth().CreateUser(req.Email, req.Password, req.Role)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	writeJSON(w, http.StatusCreated, userToAdminResponse(user))
}

// UpdateUserRequest represents a request to update a user
type UpdateUserRequest struct {
	Email string `json:"email"`
	Role  string `json:"role"`
}

// HandleUpdateUser handles PUT /system/users/{id}
func (h *UserHandler) HandleUpdateUser(w http.ResponseWriter, r *http.Request) {
	c := webcontext.NewWebContext(w, r)
	id := r.PathValue("id")

	var req UpdateUserRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request body", http.StatusBadRequest)
		return
	}

	if req.Email == "" || req.Role == "" {
		http.Error(w, "Email and role are required", http.StatusBadRequest)
		return
	}

	// Self-protection: prevent admin from removing their own admin role
	if id == c.GetUserID() && req.Role != "admin" {
		http.Error(w, "Cannot remove your own admin role", http.StatusBadRequest)
		return
	}

	user, err := h.deps.Domains().Auth().UpdateUser(id, req.Email, req.Role)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	writeJSON(w, http.StatusOK, userToAdminResponse(user))
}

// UpdatePasswordRequest represents a request to change a user's password
type UpdatePasswordRequest struct {
	Password string `json:"password"`
}

// HandleUpdatePassword handles PUT /system/users/{id}/password
func (h *UserHandler) HandleUpdatePassword(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")

	var req UpdatePasswordRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request body", http.StatusBadRequest)
		return
	}

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

	if err := h.deps.Domains().Auth().UpdateUserPassword(id, req.Password); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	w.WriteHeader(http.StatusNoContent)
}

// HandleDeleteUser handles DELETE /system/users/{id}
func (h *UserHandler) HandleDeleteUser(w http.ResponseWriter, r *http.Request) {
	c := webcontext.NewWebContext(w, r)
	id := r.PathValue("id")

	// Self-protection: prevent admin from deleting themselves
	if id == c.GetUserID() {
		http.Error(w, "Cannot delete your own account", http.StatusBadRequest)
		return
	}

	if err := h.deps.Domains().Auth().DeleteUser(id); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	w.WriteHeader(http.StatusNoContent)
}