"use client";

/**
 * The group profile's Members tab: who is in the group, their role, and the
 * admin controls for changing that.
 *
 * Which controls appear follows the same rules the BFF enforces — the server is
 * the authority, this just avoids offering buttons that would be refused.
 */

import { useState } from "react";
import { Plus, ShieldMinus, ShieldPlus, UserMinus } from "lucide-react";
import { toast } from "sonner";
import { UserAvatar } from "@/components/ui/user-avatar";
import { Button } from "@/components/ui/button";
import { AddMembersDialog } from "@/components/chat/add-members-dialog";
import { chat, isGroupAdmin, type ConversationDetail } from "@/lib/chat";

const ROLE_LABEL: Record<string, string> = {
  owner: "Owner",
  admin: "Admin",
  member: "",
};

export function GroupMembersTab({
  conversationId,
  detail,
  selfId,
  onChanged,
}: {
  conversationId: string;
  detail: ConversationDetail;
  selfId: string;
  onChanged: () => void;
}) {
  const [busy, setBusy] = useState<string | null>(null);
  const [adding, setAdding] = useState(false);
  const iAmAdmin = isGroupAdmin(detail.my_role);
  const iAmOwner = detail.my_role === "owner";

  const act = async (handle: string, fn: () => Promise<unknown>, ok: string) => {
    setBusy(handle);
    try {
      await fn();
      toast.success(ok);
      onChanged();
    } catch {
      toast.error("That didn't work");
    } finally {
      setBusy(null);
    }
  };

  return (
    <div className="space-y-3">
      {iAmAdmin && (
        <Button variant="outline" size="sm" onClick={() => setAdding(true)}>
          <Plus className="size-4" /> Add members
        </Button>
      )}

      <ul className="divide-y divide-border rounded-2xl border border-border overflow-hidden">
        {detail.participants.map((m) => {
          const isSelf = m.id === selfId;
          // The owner cannot be demoted or removed by anyone, and only the
          // owner may change roles at all.
          const canChangeRole = iAmOwner && !isSelf && m.role !== "owner";
          // An admin may remove members; only the owner may remove an admin.
          const canRemove =
            !isSelf &&
            m.role !== "owner" &&
            (iAmOwner || (iAmAdmin && m.role !== "admin"));

          return (
            <li key={m.id} className="flex items-center gap-3 px-4 py-3">
              <UserAvatar
                src={m.avatar_url}
                name={m.name}
                className="size-9 shrink-0"
              />
              <div className="min-w-0 flex-1">
                <p className="truncate text-sm font-medium text-foreground">
                  {m.name}
                  {isSelf && (
                    <span className="text-muted-foreground"> (you)</span>
                  )}
                </p>
                <p className="truncate text-xs text-muted-foreground">
                  @{m.handle}
                </p>
              </div>

              {m.role && ROLE_LABEL[m.role] && (
                <span className="shrink-0 rounded-full bg-muted px-2 py-0.5 text-[11px] font-medium text-muted-foreground">
                  {ROLE_LABEL[m.role]}
                </span>
              )}

              {canChangeRole && (
                <button
                  type="button"
                  disabled={busy === m.handle}
                  aria-label={
                    m.role === "admin" ? "Remove admin" : "Make admin"
                  }
                  onClick={() =>
                    act(
                      m.handle,
                      () =>
                        chat.setMemberRole(
                          conversationId,
                          m.handle,
                          m.role === "admin" ? "member" : "admin",
                        ),
                      m.role === "admin"
                        ? `${m.name} is no longer an admin`
                        : `${m.name} is now an admin`,
                    )
                  }
                  className="shrink-0 rounded-md p-1.5 text-muted-foreground hover:text-foreground disabled:opacity-40"
                >
                  {m.role === "admin" ? (
                    <ShieldMinus className="size-4" />
                  ) : (
                    <ShieldPlus className="size-4" />
                  )}
                </button>
              )}

              {canRemove && (
                <button
                  type="button"
                  disabled={busy === m.handle}
                  aria-label={`Remove ${m.name}`}
                  onClick={() => {
                    if (!window.confirm(`Remove ${m.name} from the group?`)) return;
                    void act(
                      m.handle,
                      () => chat.removeMember(conversationId, m.handle),
                      `${m.name} was removed`,
                    );
                  }}
                  className="shrink-0 rounded-md p-1.5 text-destructive hover:opacity-80 disabled:opacity-40"
                >
                  <UserMinus className="size-4" />
                </button>
              )}
            </li>
          );
        })}
      </ul>

      {adding && (
        <AddMembersDialog
          conversationId={conversationId}
          existing={detail.participants.map((p) => p.handle)}
          onClose={() => setAdding(false)}
          onAdded={onChanged}
        />
      )}
    </div>
  );
}