"use client";

import { useState } from "react";
import { useRouter } from "next/navigation";
import { CalendarCheckIcon, CheckIcon, MinusIcon, XIcon } from "lucide-react";
import { cn } from "@/lib/utils";
import { Button } from "@/components/ui/button";
import { Item, ItemContent, ItemHeader, ItemTitle } from "@/components/ui/item";
import { setMissionAttendance } from "@/app/(frontend)/intelligence/missions/actions";

type AttendanceResponse = "yes" | "no" | "tentative";

interface Attendee {
  id: number;
  name: string;
}

interface MissionAttendanceProps {
  missionId: number;
  currentUserId: number | null;
  currentResponse: AttendanceResponse | null;
  attendanceClosed?: boolean;
  yes: Attendee[];
  no: Attendee[];
  tentative: Attendee[];
}

const stateMeta: Record<
  AttendanceResponse,
  { label: string; icon: typeof CheckIcon; color: string; active: string }
> = {
  yes: {
    label: "Yes",
    icon: CheckIcon,
    color: "text-green-400",
    active: "border-green-500/60 bg-green-500/15 text-green-400 hover:bg-green-500/25",
  },
  no: {
    label: "No",
    icon: XIcon,
    color: "text-red-400",
    active: "border-red-500/60 bg-red-500/15 text-red-400 hover:bg-red-500/25",
  },
  tentative: {
    label: "Tentative",
    icon: MinusIcon,
    color: "text-amber-400",
    active: "border-amber-500/60 bg-amber-500/15 text-amber-400 hover:bg-amber-500/25",
  },
};

const states = Object.keys(stateMeta) as AttendanceResponse[];

export function MissionAttendance({
  missionId,
  currentUserId,
  currentResponse,
  attendanceClosed = false,
  yes,
  no,
  tentative,
}: MissionAttendanceProps) {
  const router = useRouter();
  const [selected, setSelected] = useState<AttendanceResponse | null>(currentResponse);
  const [pending, setPending] = useState<AttendanceResponse | null>(null);
  const [error, setError] = useState<string | null>(null);

  const groups: Record<AttendanceResponse, Attendee[]> = { yes, no, tentative };

  async function handleSet(response: AttendanceResponse) {
    setPending(response);
    setSelected(response);
    setError(null);
    const res = await setMissionAttendance({ missionId, response });
    if (!res.success) {
      setSelected(currentResponse);
      setError(res.error ?? "Failed to update attendance.");
    }
    setPending(null);
    router.refresh();
  }

  return (
    <Item variant="outline">
      <ItemHeader>
        <div className="flex items-center gap-2">
          <CalendarCheckIcon className="size-4 text-muted-foreground" />
          <ItemTitle>Attendance</ItemTitle>
        </div>
      </ItemHeader>
      <ItemContent className="flex flex-col gap-3">
        {currentUserId !== null && !attendanceClosed && (
          <div className="flex items-center gap-1.5">
            {states.map((response) => {
              const meta = stateMeta[response];
              const Icon = meta.icon;
              return (
                <Button
                  key={response}
                  size="sm"
                  variant="outline"
                  className={cn("flex-1", selected === response && meta.active)}
                  disabled={pending !== null}
                  onClick={() => handleSet(response)}
                >
                  <Icon className="size-3.5" />
                  {meta.label}
                </Button>
              );
            })}
          </div>
        )}
        {currentUserId !== null && attendanceClosed && (
          <p className="text-xs text-muted-foreground">
            Attendance is closed for this mission.
          </p>
        )}
        {error && <p className="text-xs text-red-400">{error}</p>}
        {states.map((response) => {
          const meta = stateMeta[response];
          const Icon = meta.icon;
          const people = groups[response]
            .slice()
            .sort((a, b) => a.name.localeCompare(b.name));
          return (
            <div key={response} className="flex flex-col gap-1">
              <div className="flex items-center gap-1.5 text-xs font-semibold uppercase tracking-wider">
                <Icon className={cn("size-3.5", meta.color)} />
                <span className={meta.color}>{meta.label}</span>
                <span className="font-mono text-muted-foreground">
                  ({people.length})
                </span>
              </div>
              {people.length > 0 && (
                <ul className="flex flex-wrap gap-x-3 gap-y-0.5">
                  {people.map((person) => (
                    <li
                      key={person.id}
                      className={cn(
                        "text-sm",
                        person.id === currentUserId
                          ? "text-foreground font-medium"
                          : "text-muted-foreground",
                      )}
                    >
                      {person.name}
                    </li>
                  ))}
                </ul>
              )}
            </div>
          );
        })}
      </ItemContent>
    </Item>
  );
}