"use client";

import { useEffect, useState } from "react";
import { useRouter } from "next/navigation";
import Swal from "sweetalert2";

interface User {
  id: string;
  name: string | null;
  email: string;
  role: string;
  emailVerified: boolean;
  createdAt: string;
}

interface AdminApiKeyRow {
  id: string;
  name: string;
  keyPreview: string;
  expiresAt: string | null;
  daysRemaining: number | null;
  remainingLabel: string;
  lastUsedAt: string | null;
  isActive: boolean;
  createdAt: string;
}

interface Session {
  user: {
    id: string;
    email: string;
    name?: string;
    role?: string;
  };
}

export default function AdminPanel() {
  const router = useRouter();
  const [users, setUsers] = useState<User[]>([]);
  const [loading, setLoading] = useState(true);
  const [currentUserRole, setCurrentUserRole] = useState<string>("");
  const [keysModalUser, setKeysModalUser] = useState<User | null>(null);
  const [userKeys, setUserKeys] = useState<AdminApiKeyRow[]>([]);
  const [keysLoading, setKeysLoading] = useState(false);
  const [keysPatching, setKeysPatching] = useState<string | null>(null);
  const [expiryDraft, setExpiryDraft] = useState<Record<string, string>>({});

  useEffect(() => {
    checkAuth();
  }, []);

  const checkAuth = async () => {
    try {
      const res = await fetch("/api/auth/get-session", {
        credentials: "include",
      });
      
      if (!res.ok) {
        router.push("/login");
        return;
      }

      const session: Session = await res.json();
      
      if (!session.user || session.user.role !== "admin") {
        await Swal.fire({
          icon: "error",
          title: "Erişim Engellendi",
          text: "Bu sayfaya erişim yetkiniz yok. Sadece adminler görebilir.",
          confirmButtonColor: "#3b82f6",
        });
        router.push("/");
        return;
      }

      setCurrentUserRole(session.user.role || "user");
      await fetchUsers();
    } catch (err) {
      router.push("/login");
    }
  };

  const fetchUsers = async () => {
    setLoading(true);
    
    try {
      const res = await fetch("/api/admin/users", {
        credentials: "include",
      });

      if (!res.ok) {
        if (res.status === 401) {
          router.push("/login");
          return;
        }
        if (res.status === 403) {
          await Swal.fire({
            icon: "error",
            title: "Yetki Hatası",
            text: "Bu sayfaya erişim yetkiniz yok.",
            confirmButtonColor: "#3b82f6",
          });
          return;
        }
        throw new Error("Kullanıcılar yüklenemedi");
      }

      const data = await res.json();
      setUsers(data.data.users);
    } catch (err: any) {
      await Swal.fire({
        icon: "error",
        title: "Hata",
        text: err.message,
        confirmButtonColor: "#3b82f6",
      });
    } finally {
      setLoading(false);
    }
  };

  const changeRole = async (userId: string, newRole: string, currentRole: string) => {
    const result = await Swal.fire({
      title: "Rol Değiştir",
      text: `Bu kullanıcının rolünü "${currentRole}" → "${newRole}" olarak değiştirmek istediğinizden emin misiniz?`,
      icon: "question",
      showCancelButton: true,
      confirmButtonColor: "#3b82f6",
      cancelButtonColor: "#6b7280",
      confirmButtonText: "Evet, değiştir",
      cancelButtonText: "İptal",
    });

    if (!result.isConfirmed) {
      await fetchUsers();
      return;
    }

    try {
      const res = await fetch(`/api/admin/users/${userId}/role`, {
        method: "PATCH",
        credentials: "include",
        headers: {
          "Content-Type": "application/json",
        },
        body: JSON.stringify({ role: newRole }),
      });

      if (!res.ok) {
        const data = await res.json();
        throw new Error(data.error || "Rol güncellenemedi");
      }

      await Swal.fire({
        icon: "success",
        title: "Başarılı!",
        text: "Kullanıcı rolü güncellendi",
        timer: 2000,
        showConfirmButton: false,
      });
      
      await fetchUsers();
    } catch (err: any) {
      await Swal.fire({
        icon: "error",
        title: "Hata",
        text: err.message,
        confirmButtonColor: "#3b82f6",
      });
      await fetchUsers();
    }
  };

  const toggleEmailVerification = async (userId: string, currentStatus: boolean, email: string) => {
    const newStatus = !currentStatus;
    const result = await Swal.fire({
      title: "Email Doğrulama",
      text: `${email} için email doğrulamasını ${newStatus ? "aktif" : "pasif"} yapmak istiyor musunuz?`,
      icon: "question",
      showCancelButton: true,
      confirmButtonColor: "#3b82f6",
      cancelButtonColor: "#6b7280",
      confirmButtonText: "Evet, değiştir",
      cancelButtonText: "İptal",
    });

    if (!result.isConfirmed) {
      return;
    }

    try {
      const res = await fetch(`/api/admin/users/${userId}/verification`, {
        method: "PATCH",
        credentials: "include",
        headers: {
          "Content-Type": "application/json",
        },
        body: JSON.stringify({ emailVerified: newStatus }),
      });

      if (!res.ok) {
        const data = await res.json();
        throw new Error(data.error || "Doğrulama güncellenemedi");
      }

      await Swal.fire({
        icon: "success",
        title: "Başarılı!",
        text: `Email doğrulama ${newStatus ? "aktif edildi" : "pasif edildi"}`,
        timer: 2000,
        showConfirmButton: false,
      });
      
      await fetchUsers();
    } catch (err: any) {
      await Swal.fire({
        icon: "error",
        title: "Hata",
        text: err.message,
        confirmButtonColor: "#3b82f6",
      });
    }
  };

  const fetchUserKeysList = async (userId: string) => {
    setKeysLoading(true);
    try {
      const res = await fetch(`/api/v1/admin/users/${userId}/api-keys`, {
        credentials: "include",
      });
      const data = await res.json();
      if (!res.ok) {
        throw new Error(data.error || "Anahtarlar yüklenemedi");
      }
      setUserKeys(data.data?.keys || []);
    } finally {
      setKeysLoading(false);
    }
  };

  const openApiKeysModal = async (u: User) => {
    setKeysModalUser(u);
    setUserKeys([]);
    setExpiryDraft({});
    try {
      await fetchUserKeysList(u.id);
    } catch (err: any) {
      await Swal.fire({
        icon: "error",
        title: "Hata",
        text: err.message,
        confirmButtonColor: "#3b82f6",
      });
      setKeysModalUser(null);
    }
  };

  const patchKeyExpiry = async (userId: string, keyId: string, draft: string) => {
    let expiresInDays: number | null;
    const t = draft.trim();
    if (t === "") {
      expiresInDays = null;
    } else {
      const n = parseInt(t, 10);
      if (!Number.isFinite(n) || n < 0) {
        await Swal.fire({
          icon: "warning",
          title: "Geçersiz",
          text: "Gün sayısı boş (süresiz) veya 0 veya pozitif tam sayı olmalı.",
          confirmButtonColor: "#3b82f6",
        });
        return;
      }
      expiresInDays = n === 0 ? null : n;
    }
    setKeysPatching(keyId);
    try {
      const res = await fetch(
        `/api/v1/admin/users/${userId}/api-keys/${keyId}`,
        {
          method: "PATCH",
          credentials: "include",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify({ expiresInDays }),
        }
      );
      const data = await res.json();
      if (!res.ok) {
        throw new Error(data.error || "Güncellenemedi");
      }
      await Swal.fire({
        icon: "success",
        title: "Güncellendi",
        text: "API anahtarı süresi kaydedildi.",
        timer: 1800,
        showConfirmButton: false,
      });
      setExpiryDraft((prev) => {
        const next = { ...prev };
        delete next[keyId];
        return next;
      });
      await fetchUserKeysList(userId);
    } catch (err: any) {
      await Swal.fire({
        icon: "error",
        title: "Hata",
        text: err.message,
        confirmButtonColor: "#3b82f6",
      });
    } finally {
      setKeysPatching(null);
    }
  };

  const deleteUser = async (userId: string, email: string) => {
    const result = await Swal.fire({
      title: "Kullanıcıyı Sil",
      html: `<b>${email}</b> kullanıcısını silmek istediğinizden emin misiniz?<br><br>
             <span style="color: #ef4444; font-weight: 600;">⚠️ Bu işlem geri alınamaz!</span><br>
             <small>Kullanıcının tüm resimleri ve verileri silinecek.</small>`,
      icon: "warning",
      showCancelButton: true,
      confirmButtonColor: "#ef4444",
      cancelButtonColor: "#6b7280",
      confirmButtonText: "Evet, sil!",
      cancelButtonText: "İptal",
    });

    if (!result.isConfirmed) {
      return;
    }

    try {
      const res = await fetch(`/api/admin/users/${userId}`, {
        method: "DELETE",
        credentials: "include",
      });

      if (!res.ok) {
        const data = await res.json();
        throw new Error(data.error || "Kullanıcı silinemedi");
      }

      await Swal.fire({
        icon: "success",
        title: "Silindi!",
        text: "Kullanıcı başarıyla silindi",
        timer: 2000,
        showConfirmButton: false,
      });
      
      await fetchUsers();
    } catch (err: any) {
      await Swal.fire({
        icon: "error",
        title: "Hata",
        text: err.message,
        confirmButtonColor: "#3b82f6",
      });
    }
  };

  const getRoleBadgeColor = (role: string) => {
    switch (role) {
      case "admin":
        return "bg-red-100 text-red-800 border-red-200";
      case "moderator":
        return "bg-blue-100 text-blue-800 border-blue-200";
      default:
        return "bg-gray-100 text-gray-800 border-gray-200";
    }
  };

  if (loading) {
    return (
      <div className="min-h-screen bg-gradient-to-br from-slate-50 via-blue-50 to-indigo-100 flex items-center justify-center">
        <div className="text-center">
          <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-blue-600 mx-auto"></div>
          <p className="mt-4 text-gray-600">Yükleniyor...</p>
        </div>
      </div>
    );
  }

  return (
    <div className="min-h-screen bg-gradient-to-br from-slate-50 via-blue-50 to-indigo-100 p-8">
      <div className="max-w-7xl mx-auto">
        <div className="mb-8">
          <h1 className="text-4xl font-bold text-gray-900 mb-2">Admin Panel</h1>
          <p className="text-gray-600">Kullanıcı yönetimi ve rol atama</p>
        </div>

        <div className="bg-white rounded-2xl shadow-xl overflow-hidden border border-gray-100">
          <div className="overflow-x-auto">
            <table className="w-full">
              <thead className="bg-gradient-to-r from-blue-600 to-indigo-600 text-white">
                <tr>
                  <th className="px-6 py-4 text-left text-sm font-semibold">Kullanıcı</th>
                  <th className="px-6 py-4 text-left text-sm font-semibold">Email</th>
                  <th className="px-6 py-4 text-left text-sm font-semibold">Rol</th>
                  <th className="px-6 py-4 text-left text-sm font-semibold">Doğrulama</th>
                  <th className="px-6 py-4 text-left text-sm font-semibold">Kayıt Tarihi</th>
                  <th className="px-6 py-4 text-left text-sm font-semibold">İşlemler</th>
                </tr>
              </thead>
              <tbody className="divide-y divide-gray-200">
                {users.map((user) => (
                  <tr key={user.id} className="hover:bg-gray-50 transition-colors">
                    <td className="px-6 py-4">
                      <div className="font-medium text-gray-900">
                        {user.name || "İsimsiz"}
                      </div>
                      <div className="text-xs text-gray-500">{user.id.substring(0, 8)}</div>
                    </td>
                    <td className="px-6 py-4 text-gray-700">{user.email}</td>
                    <td className="px-6 py-4">
                      <select
                        value={user.role}
                        onChange={(e) => changeRole(user.id, e.target.value, user.role)}
                        className={`px-3 py-1 rounded-full text-sm font-medium border ${getRoleBadgeColor(
                          user.role
                        )} focus:outline-none focus:ring-2 focus:ring-blue-500 cursor-pointer transition-all hover:shadow-md`}
                      >
                        <option value="user">User</option>
                        <option value="moderator">Moderator</option>
                        <option value="admin">Admin</option>
                      </select>
                    </td>
                    <td className="px-6 py-4">
                      <button
                        onClick={() => toggleEmailVerification(user.id, user.emailVerified, user.email)}
                        className={`inline-flex items-center gap-1 px-3 py-1.5 rounded-full text-xs font-medium transition-all cursor-pointer hover:shadow-md ${
                          user.emailVerified
                            ? "bg-green-100 text-green-700 hover:bg-green-200"
                            : "bg-yellow-100 text-yellow-700 hover:bg-yellow-200"
                        }`}
                      >
                        {user.emailVerified ? (
                          <>
                            <svg className="w-3 h-3" fill="currentColor" viewBox="0 0 20 20">
                              <path
                                fillRule="evenodd"
                                d="M16.707 5.293a1 1 0 010 1.414l-8 8a1 1 0 01-1.414 0l-4-4a1 1 0 011.414-1.414L8 12.586l7.293-7.293a1 1 0 011.414 0z"
                                clipRule="evenodd"
                              />
                            </svg>
                            Doğrulandı
                          </>
                        ) : (
                          <>
                            <svg className="w-3 h-3" fill="currentColor" viewBox="0 0 20 20">
                              <path
                                fillRule="evenodd"
                                d="M10 18a8 8 0 100-16 8 8 0 000 16zM8.707 7.293a1 1 0 00-1.414 1.414L8.586 10l-1.293 1.293a1 1 0 101.414 1.414L10 11.414l1.293 1.293a1 1 0 001.414-1.414L11.414 10l1.293-1.293a1 1 0 00-1.414-1.414L10 8.586 8.707 7.293z"
                                clipRule="evenodd"
                              />
                            </svg>
                            Beklemede
                          </>
                        )}
                      </button>
                    </td>
                    <td className="px-6 py-4 text-sm text-gray-600">
                      {new Date(user.createdAt).toLocaleDateString("tr-TR")}
                    </td>
                    <td className="px-6 py-4">
                      <div className="flex flex-wrap gap-2">
                        <button
                          type="button"
                          onClick={() => openApiKeysModal(user)}
                          className="px-4 py-2 bg-indigo-600 hover:bg-indigo-700 text-white rounded-lg text-sm font-medium transition-colors"
                        >
                          API Keys
                        </button>
                        <button
                          type="button"
                          onClick={() => deleteUser(user.id, user.email)}
                          className="px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg text-sm font-medium transition-colors"
                        >
                          Sil
                        </button>
                      </div>
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        </div>

        {keysModalUser && (
          <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50 p-4">
            <div className="max-h-[90vh] w-full max-w-3xl overflow-y-auto rounded-2xl bg-white p-6 shadow-2xl">
              <div className="mb-4 flex items-start justify-between gap-4">
                <div>
                  <h2 className="text-xl font-bold text-gray-900">API anahtarları</h2>
                  <p className="text-sm text-gray-600">
                    {keysModalUser.email} — süre: bugünden itibaren gün sayısı (boş veya 0 =
                    süresiz)
                  </p>
                </div>
                <button
                  type="button"
                  onClick={() => setKeysModalUser(null)}
                  className="rounded-lg px-3 py-1 text-sm text-gray-600 hover:bg-gray-100"
                >
                  Kapat
                </button>
              </div>
              {keysLoading ? (
                <p className="text-gray-600">Yükleniyor…</p>
              ) : userKeys.length === 0 ? (
                <p className="text-gray-600">Bu kullanıcının henüz API anahtarı yok.</p>
              ) : (
                <div className="overflow-x-auto">
                  <table className="w-full text-left text-sm">
                    <thead>
                      <tr className="border-b border-gray-200">
                        <th className="py-2 pr-3">İsim</th>
                        <th className="py-2 pr-3">Önizleme</th>
                        <th className="py-2 pr-3">Mevcut bitiş</th>
                        <th className="py-2 pr-3">Kalan süre</th>
                        <th className="py-2 pr-3">Yeni süre (gün)</th>
                        <th className="py-2" />
                      </tr>
                    </thead>
                    <tbody>
                      {userKeys.map((k) => (
                        <tr key={k.id} className="border-b border-gray-100">
                          <td className="py-2 pr-3 font-medium">{k.name}</td>
                          <td className="py-2 pr-3 font-mono text-xs">{k.keyPreview}</td>
                          <td className="py-2 pr-3 text-xs">
                            {k.expiresAt
                              ? new Date(k.expiresAt).toLocaleString("tr-TR")
                              : "—"}
                          </td>
                          <td className="py-2 pr-3">
                            <span
                              className={
                                k.remainingLabel === "Süresi doldu"
                                  ? "font-medium text-red-600"
                                  : k.remainingLabel === "Süresiz"
                                    ? "text-gray-600"
                                    : "font-medium text-emerald-700"
                              }
                            >
                              {k.remainingLabel}
                            </span>
                          </td>
                          <td className="py-2 pr-3">
                            <input
                              type="number"
                              min={0}
                              placeholder="0=süresiz"
                              value={expiryDraft[k.id] ?? ""}
                              onChange={(e) =>
                                setExpiryDraft((prev) => ({
                                  ...prev,
                                  [k.id]: e.target.value,
                                }))
                              }
                              className="w-28 rounded border border-gray-300 px-2 py-1 text-sm"
                            />
                          </td>
                          <td className="py-2">
                            <button
                              type="button"
                              disabled={keysPatching === k.id}
                              onClick={() =>
                                patchKeyExpiry(
                                  keysModalUser.id,
                                  k.id,
                                  expiryDraft[k.id] ?? ""
                                )
                              }
                              className="rounded bg-blue-600 px-3 py-1 text-xs font-medium text-white hover:bg-blue-700 disabled:opacity-50"
                            >
                              {keysPatching === k.id ? "…" : "Kaydet"}
                            </button>
                          </td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
              )}
            </div>
          </div>
        )}

        <div className="mt-8 grid grid-cols-1 md:grid-cols-4 gap-6">
          <div className="bg-white p-6 rounded-xl shadow-lg border border-gray-100">
            <h3 className="text-sm font-medium text-gray-600 mb-2">Toplam Kullanıcı</h3>
            <p className="text-3xl font-bold text-gray-900">{users.length}</p>
          </div>
          <div className="bg-white p-6 rounded-xl shadow-lg border border-gray-100">
            <h3 className="text-sm font-medium text-gray-600 mb-2">Admin Sayısı</h3>
            <p className="text-3xl font-bold text-red-600">
              {users.filter((u) => u.role === "admin").length}
            </p>
          </div>
          <div className="bg-white p-6 rounded-xl shadow-lg border border-gray-100">
            <h3 className="text-sm font-medium text-gray-600 mb-2">Moderatör Sayısı</h3>
            <p className="text-3xl font-bold text-blue-600">
              {users.filter((u) => u.role === "moderator").length}
            </p>
          </div>
          <div className="bg-white p-6 rounded-xl shadow-lg border border-gray-100">
            <h3 className="text-sm font-medium text-gray-600 mb-2">Doğrulananlar</h3>
            <p className="text-3xl font-bold text-green-600">
              {users.filter((u) => u.emailVerified).length}
            </p>
          </div>
        </div>
      </div>
    </div>
  );
}