package web

import (
	"errors"
	"net/http"
	"net/url"
	"strings"

	"github.com/go-chi/chi/v5"

	"plumber/internal/store"
)

type adminUsersPage struct {
	page
	Users      []store.User
	Error      string
	Search     string
	NextCursor string
	HasMore    bool
}

func (s *Server) requireAdmin(w http.ResponseWriter, r *http.Request) *store.User {
	u := currentUser(r)
	if !u.Admin() {
		http.Error(w, "forbidden", http.StatusForbidden)
		return nil
	}
	return u
}

func (s *Server) handleAdminUsers(w http.ResponseWriter, r *http.Request) {
	if s.requireAdmin(w, r) == nil {
		return
	}
	search := strings.TrimSpace(r.URL.Query().Get("q"))
	cursorCreated := r.URL.Query().Get("cursor_created")
	cursorID := r.URL.Query().Get("cursor_id")
	users, nextCreated, nextID, err := s.store.ListUsers(r.Context(), store.ListUsersQuery{
		Search:        search,
		CursorCreated: cursorCreated,
		CursorID:      cursorID,
		Limit:         store.AdminUsersLimit,
	})
	if err != nil {
		http.Error(w, "could not load users", http.StatusInternalServerError)
		return
	}
	next := ""
	if nextCreated != "" {
		v := url.Values{}
		if search != "" {
			v.Set("q", search)
		}
		v.Set("cursor_created", nextCreated)
		v.Set("cursor_id", nextID)
		next = "/admin/users?" + v.Encode()
	}
	s.exec(w, "admin-users", adminUsersPage{
		page:       s.basePage(r, "Users"),
		Users:      users,
		Search:     search,
		NextCursor: next,
		HasMore:    next != "",
	})
}

func (s *Server) handleAdminSetRole(w http.ResponseWriter, r *http.Request) {
	if !s.requireCSRF(w, r) {
		return
	}
	if s.requireAdmin(w, r) == nil {
		return
	}
	id := chi.URLParam(r, "id")
	role := store.Role(r.PostFormValue("role"))
	err := s.store.SetUserRole(r.Context(), id, role)
	if errors.Is(err, store.ErrLastAdmin) {
		users, _, _, listErr := s.store.ListUsers(r.Context(), store.ListUsersQuery{Limit: store.AdminUsersLimit})
		if listErr != nil {
			http.Error(w, "could not demote last admin", http.StatusBadRequest)
			return
		}
		s.exec(w, "admin-users", adminUsersPage{
			page:  s.basePage(r, "Users"),
			Users: users,
			Error: "Cannot demote the last admin.",
		})
		return
	}
	if err != nil {
		http.Error(w, "could not update role", http.StatusBadRequest)
		return
	}
	http.Redirect(w, r, "/admin/users", http.StatusSeeOther)
}