import Link from "next/link";
import { AlertTriangle, Database, LockKeyhole, Plus, Search, Shield, UsersRound } from "lucide-react";
import { redirect } from "next/navigation";
import { AppShell } from "@/components/app-shell";
import { Avatar } from "@/components/avatar";
import { StatusBadge } from "@/components/status-badge";
import { SYSTEM_PERMISSIONS } from "@/lib/access";
import { prisma } from "@/lib/prisma";
import { getShellContext } from "@/lib/shell";
import { requireCurrentUser, userIsAdmin } from "@/lib/session";
import { requireInitialSetup } from "@/lib/setup";
import { DataTable, EmptyState, MetricTile, PageHeader, Panel, StatusDot, Tabs } from "@/components/ui";

export const dynamic = "force-dynamic";

const adminTabs = ["Users", "Rooms", "Roles", "Invites", "Instance", "Security"];

export default async function AdminPage({ searchParams }: { searchParams: Promise<{ tab?: string; q?: string }> }) {
  await requireInitialSetup();
  const user = await requireCurrentUser();

  if (!userIsAdmin(user)) {
    redirect("/dashboard");
  }

  const { tab = "Users", q = "" } = await searchParams;
  const activeTab = adminTabs.includes(tab) ? tab : "Users";
  const query = q.trim().toLowerCase();
  const shell = await getShellContext(user);

  const [users, rooms, roles, pendingRequests] = await Promise.all([
    prisma.user.findMany({
      include: { roles: { include: { role: true } }, _count: { select: { ownedRooms: true, roomMembers: true } } },
      orderBy: { createdAt: "asc" }
    }),
    prisma.room.findMany({
      include: { owner: true, _count: { select: { members: true, mediaSources: true } } },
      orderBy: { updatedAt: "desc" }
    }),
    prisma.role.findMany({
      include: { _count: { select: { users: true, permissions: true } } },
      orderBy: { name: "asc" }
    }),
    prisma.friendship.count({ where: { status: "PENDING" } })
  ]);
  const filteredUsers = query
    ? users.filter((account) =>
        [account.username, account.displayName || "", ...account.roles.map((role) => role.role.name)].join(" ").toLowerCase().includes(query)
      )
    : users;
  const filteredRooms = query
    ? rooms.filter((room) =>
        [room.name, room.slug, room.visibility, room.owner?.username || "", room.owner?.displayName || ""].join(" ").toLowerCase().includes(query)
      )
    : rooms;
  const filteredRoles = query
    ? roles.filter((role) => [role.name, role.description || "", role.scope].join(" ").toLowerCase().includes(query))
    : roles;

  return (
    <AppShell active="Admin" {...shell}>
      <PageHeader
        title="Admin"
        description="Operational management for accounts, rooms, roles, instance state, and security controls."
        meta={
          <>
            <StatusDot tone="good" label="admin session" />
            <StatusDot tone="good" label={`${users.length} users`} />
            <StatusDot tone={pendingRequests > 0 ? "warn" : "neutral"} label={`${pendingRequests} pending requests`} />
          </>
        }
        actions={
          <>
            <button className="button" type="button" disabled title="Invite records are not implemented yet."><Plus size={16} /> Invite</button>
            <button className="button" type="button" disabled title="Audit events need a persisted event table first."><Shield size={16} /> Audit</button>
          </>
        }
      />

      <section className="metrics-grid">
        <MetricTile label="Users" value={users.length} detail="local accounts" tone="good" />
        <MetricTile label="Rooms" value={rooms.length} detail="persistent room records" tone="info" />
        <MetricTile label="Roles" value={roles.length} detail="system and room scopes" />
        <MetricTile label="Permissions" value={SYSTEM_PERMISSIONS.length} detail="known permission keys" tone="warn" />
      </section>

      <Panel
        title="Admin Workspace"
        eyebrow="Management"
        actions={
          <form className="toolbar" action="/admin">
            <input type="hidden" name="tab" value={activeTab} />
            <label className="search-field">
              <Search size={15} />
              <input name="q" placeholder={`Search ${activeTab.toLowerCase()}`} defaultValue={q} />
            </label>
          </form>
        }
      >
        <Tabs active={activeTab} items={adminTabs.map((item) => ({ label: item, href: `/admin?tab=${encodeURIComponent(item)}` }))} />

        {activeTab === "Users" ? <UsersTable users={filteredUsers} /> : null}
        {activeTab === "Rooms" ? <RoomsTable rooms={filteredRooms} /> : null}
        {activeTab === "Roles" ? <RolesTable roles={filteredRoles} /> : null}
        {activeTab === "Invites" ? <InvitesPanel pendingRequests={pendingRequests} /> : null}
        {activeTab === "Instance" ? <InstancePanel userCount={users.length} roomCount={rooms.length} /> : null}
        {activeTab === "Security" ? <SecurityPanel /> : null}
      </Panel>
    </AppShell>
  );
}

function UsersTable({
  users
}: {
  users: Array<{
    id: string;
    username: string;
    displayName: string | null;
    createdAt: Date;
    roles: Array<{ roleId: string; role: { name: string } }>;
    _count: { ownedRooms: number; roomMembers: number };
  }>;
}) {
  return (
    <DataTable>
      <table className="table">
        <thead>
          <tr>
            <th>User</th>
            <th>Roles</th>
            <th>Rooms</th>
            <th>Created</th>
            <th>Actions</th>
          </tr>
        </thead>
        <tbody>
          {users.map((account) => (
            <tr key={account.id}>
              <td>
                <div className="row-main">
                  <Avatar name={account.displayName || account.username} size={30} />
                  <div className="row-title">
                    <strong>{account.displayName || account.username}</strong>
                    <span>@{account.username}</span>
                  </div>
                </div>
              </td>
              <td>
                <div className="status-row">
                  {account.roles.length === 0 ? <StatusBadge>user</StatusBadge> : null}
                  {account.roles.map((userRole) => (
                    <StatusBadge key={userRole.roleId} tone={userRole.role.name === "admin" ? "good" : undefined}>
                      {userRole.role.name}
                    </StatusBadge>
                  ))}
                </div>
              </td>
              <td>{account._count.ownedRooms + account._count.roomMembers}</td>
              <td>{formatDate(account.createdAt)}</td>
              <td><button className="button compact-button" type="button" disabled title="User edit and ban actions are not implemented yet.">Manage</button></td>
            </tr>
          ))}
        </tbody>
      </table>
    </DataTable>
  );
}

function RoomsTable({
  rooms
}: {
  rooms: Array<{
    id: string;
    slug: string;
    name: string;
    visibility: string;
    updatedAt: Date;
    owner: { username: string; displayName: string | null } | null;
    _count: { members: number; mediaSources: number };
  }>;
}) {
  return (
    <DataTable>
      <table className="table">
        <thead>
          <tr>
            <th>Room</th>
            <th>Owner</th>
            <th>Access</th>
            <th>State</th>
            <th>Updated</th>
            <th />
          </tr>
        </thead>
        <tbody>
          {rooms.map((room) => (
            <tr key={room.id}>
              <td>
                <div className="row-title">
                  <strong>{room.name}</strong>
                  <span>/{room.slug}</span>
                </div>
              </td>
              <td>{room.owner?.displayName || room.owner?.username || "Unassigned"}</td>
              <td><StatusBadge>{room.visibility.toLowerCase().replace("_", " ")}</StatusBadge></td>
              <td>{room._count.members + 1} users / {room._count.mediaSources} media</td>
              <td>{formatDate(room.updatedAt)}</td>
              <td><Link className="button compact-button" href={`/rooms/${encodeURIComponent(room.slug)}`}>Open</Link></td>
            </tr>
          ))}
        </tbody>
      </table>
    </DataTable>
  );
}

function RolesTable({
  roles
}: {
  roles: Array<{
    id: string;
    name: string;
    description: string | null;
    scope: string;
    _count: { users: number; permissions: number };
  }>;
}) {
  return roles.length === 0 ? (
    <EmptyState title="No roles defined" />
  ) : (
    <div className="split-grid">
      <Panel title="Roles" eyebrow="Assignments">
        {roles.map((role) => (
          <div className="row" key={role.id}>
            <div className="row-title">
              <strong>{role.name}</strong>
              <span>{role.description || `${role.scope.toLowerCase()} role`}</span>
            </div>
            <StatusBadge>{role._count.users} users / {role._count.permissions} permissions</StatusBadge>
          </div>
        ))}
      </Panel>
      <Panel title="Permissions" eyebrow="Known keys">
        {SYSTEM_PERMISSIONS.map((permission) => (
          <div className="row" key={permission}>
            <div className="row-title">
              <strong>{permission}</strong>
              <span>Assignable to system roles</span>
            </div>
            <StatusBadge>Enabled</StatusBadge>
          </div>
        ))}
      </Panel>
    </div>
  );
}

function InvitesPanel({ pendingRequests }: { pendingRequests: number }) {
  return (
    <div className="split-grid">
      <Panel title="Room Invites" eyebrow="Pending">
        <EmptyState title="Room invite creation is not wired yet" description="The management surface is reserved so invite CRUD can be added without a layout change." />
      </Panel>
      <Panel title="Friend Requests" eyebrow="Instance">
        <div className="setting-row">
          <UsersRound size={16} />
          <span>
            <strong>{pendingRequests} pending friend requests</strong>
            <small>Handled by each receiving user in People.</small>
          </span>
        </div>
      </Panel>
    </div>
  );
}

function InstancePanel({ userCount, roomCount }: { userCount: number; roomCount: number }) {
  return (
    <div className="split-grid">
      <Panel title="Runtime" eyebrow="Container">
        <div className="settings-list">
          <Setting icon={<Database size={16} />} label="Database" value="Postgres via DATABASE_URL" />
          <Setting icon={<Shield size={16} />} label="Sessions" value="Signed HTTP-only cookie" />
          <Setting icon={<UsersRound size={16} />} label="Accounts" value={`${userCount} users`} />
          <Setting icon={<Database size={16} />} label="Rooms" value={`${roomCount} rooms`} />
        </div>
      </Panel>
      <Panel title="Health" eyebrow="Status">
        <div className="settings-list">
          <StatusDot tone="good" label="Admin page rendered" />
          <StatusDot tone="good" label="Database query succeeded" />
          <StatusDot tone="info" label="Socket endpoint configured at /api/socket" />
        </div>
      </Panel>
    </div>
  );
}

function SecurityPanel() {
  return (
    <div className="split-grid">
      <Panel title="Security Controls" eyebrow="Policy">
        <div className="settings-list">
          <Setting icon={<LockKeyhole size={16} />} label="Password storage" value="bcrypt hash" />
          <Setting icon={<Shield size={16} />} label="Admin check" value="Server-side role lookup" />
          <Setting icon={<AlertTriangle size={16} />} label="Registration mode" value="Open registration" />
        </div>
      </Panel>
      <Panel title="Danger Zone" eyebrow="Destructive">
        <EmptyState title="Destructive actions are disabled" description="User banning, registration mode changes, and deletion need server actions before controls become active." />
      </Panel>
    </div>
  );
}

function Setting({ icon, label, value }: { icon: React.ReactNode; label: string; value: string }) {
  return (
    <div className="setting-row">
      {icon}
      <span>
        <strong>{label}</strong>
        <small>{value}</small>
      </span>
    </div>
  );
}

function formatDate(date: Date) {
  return new Intl.DateTimeFormat("en", { month: "short", day: "numeric", year: "numeric" }).format(date);
}