"use client";

import { useMemo, useState } from "react";
import Link from "next/link";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import dayjs from "dayjs";
import { toast } from "sonner";
import { Button, Card, CardContent, PageHeader, Select } from "@/components/ds";
import { useCurrentHub } from "@/modules/workspace/hooks/useCurrentHub";
import { workspaceApi } from "@/modules/workspace/services/workspace-api";
import { CHANNEL, CONTENT_STATUS, CONTENT_TYPE, displayPerson, formatWhen, labelOf } from "@/modules/workspace/labels";
import { StatusChip } from "@/modules/workspace/components/StatusChip";
import { WorkspaceEmptyState, WorkspacePageError, WorkspacePageLoader } from "@/modules/workspace/pages/shared";
import type { WorkspaceRecord } from "@/modules/workspace/types";

type View = "month" | "week" | "list";

function startOfWeek(date: dayjs.Dayjs) {
  const weekday = date.day();
  return date.subtract((weekday + 1) % 7, "day").startOf("day");
}

export const WorkspaceContentCalendar = function WorkspaceContentCalendarPage() {
  const queryClient = useQueryClient();
  const { tenantId, hubId, loading } = useCurrentHub();
  const [view, setView] = useState<View>("month");
  const [cursor, setCursor] = useState(dayjs());
  const [channel, setChannel] = useState("");
  const [status, setStatus] = useState("");
  const [contentType, setContentType] = useState("");
  const projects = useQuery({
    queryKey: ["workspace", tenantId, "projects", hubId],
    queryFn: () => workspaceApi.projects.list(tenantId!, { work_hub_id: hubId! }),
    enabled: !!tenantId && !!hubId,
  });
  const projectNames = Object.fromEntries(
    (projects.data ?? []).map((project) => [String(project.id), String(project.name || "پروژه")]),
  );
  const items = useQuery({
    queryKey: ["workspace", tenantId, "calendar", hubId, channel, status, contentType],
    queryFn: () =>
      workspaceApi.content.calendar(tenantId!, {
        work_hub_id: hubId!,
        channel: channel || undefined,
        status: status || undefined,
        content_type: contentType || undefined,
      }),
    enabled: !!tenantId && !!hubId,
  });
  const reschedule = useMutation({
    mutationFn: ({ id, scheduled_at }: { id: string; scheduled_at: string }) =>
      workspaceApi.content.update(tenantId!, id, { scheduled_at }),
    onSuccess: () => {
      toast.success("زمان‌بندی ذخیره شد");
      void queryClient.invalidateQueries({ queryKey: ["workspace", tenantId, "calendar"] });
    },
    onError: (err) => toast.error(err instanceof Error ? err.message : "تغییر زمان‌بندی ناموفق بود"),
  });

  const days = useMemo(() => {
    if (view === "week") {
      const start = startOfWeek(cursor);
      return Array.from({ length: 7 }, (_, index) => start.add(index, "day"));
    }
    const start = cursor.startOf("month");
    const gridStart = startOfWeek(start);
    return Array.from({ length: 42 }, (_, index) => gridStart.add(index, "day"));
  }, [cursor, view]);

  const byDay = useMemo(() => {
    const map = new Map<string, WorkspaceRecord[]>();
    for (const item of items.data ?? []) {
      const key = item.scheduled_at ? dayjs(String(item.scheduled_at)).format("YYYY-MM-DD") : "";
      if (!key) continue;
      map.set(key, [...(map.get(key) ?? []), item]);
    }
    return map;
  }, [items.data]);

  if (!tenantId || loading || items.isLoading) return <WorkspacePageLoader />;
  if (!hubId) return <WorkspaceEmptyState title="مرکز کار لازم است" description="ابتدا مرکز کار را انتخاب کنید." />;
  if (items.error) return <WorkspacePageError error={items.error} onRetry={() => items.refetch()} />;

  return (
    <div className="space-y-6">
      <PageHeader
        title="تقویم محتوا"
        description="آیتم‌های زمان‌بندی‌شده. کشیدن کارت به روز دیگر، زمان را در سرور ذخیره می‌کند."
        actions={
          <div className="flex flex-wrap gap-2">
            <Button variant="outline" onClick={() => setCursor((value) => value.subtract(1, view === "week" ? "week" : "month"))}>
              قبلی
            </Button>
            <Button variant="outline" onClick={() => setCursor(dayjs())}>
              امروز
            </Button>
            <Button variant="outline" onClick={() => setCursor((value) => value.add(1, view === "week" ? "week" : "month"))}>
              بعدی
            </Button>
          </div>
        }
      />
      <div className="flex flex-wrap gap-2">
        {(["month", "week", "list"] as View[]).map((mode) => (
          <Button key={mode} variant={view === mode ? "default" : "outline"} onClick={() => setView(mode)}>
            {mode === "month" ? "ماه" : mode === "week" ? "هفته" : "فهرست"}
          </Button>
        ))}
        <Select value={channel} onChange={(event) => setChannel(event.target.value)}>
          <option value="">همه کانال‌ها</option>
          {Object.entries(CHANNEL).map(([value, label]) => (
            <option key={value} value={value}>
              {label}
            </option>
          ))}
        </Select>
        <Select value={contentType} onChange={(event) => setContentType(event.target.value)}>
          <option value="">همه انواع</option>
          {Object.entries(CONTENT_TYPE).map(([value, label]) => (
            <option key={value} value={value}>
              {label}
            </option>
          ))}
        </Select>
        <Select value={status} onChange={(event) => setStatus(event.target.value)}>
          <option value="">همه وضعیت‌ها</option>
          {Object.entries(CONTENT_STATUS).map(([value, label]) => (
            <option key={value} value={value}>
              {label}
            </option>
          ))}
        </Select>
      </div>
      {view === "list" ? (
        <div className="space-y-2">
          {(items.data ?? []).length === 0 ? (
            <WorkspaceEmptyState title="زمان‌بندی‌ای نیست" description="محتوا را زمان‌بندی کنید تا در تقویم دیده شود." />
          ) : (
            (items.data ?? []).map((item) => (
              <Card key={String(item.id)}>
                <CardContent className="flex flex-wrap items-center justify-between gap-3 p-4">
                  <div>
                    <Link href={`/workspace/content/${item.id}`} className="font-medium text-secondary">
                      {String(item.title || "محتوا")}
                    </Link>
                    <p className="text-xs text-[var(--muted)]">
                      {labelOf(CONTENT_TYPE, String(item.content_type || ""))} · {labelOf(CHANNEL, String(item.channel || ""))} ·{" "}
                      {projectNames[String(item.project_id || "")] || "بدون پروژه"} ·{" "}
                      {displayPerson(String(item.owner_user_id || ""))}
                    </p>
                  </div>
                  <div className="flex items-center gap-2">
                    <StatusChip value={String(item.status || "")} />
                    <span className="text-sm text-[var(--muted)]">{formatWhen(String(item.scheduled_at || ""))}</span>
                  </div>
                </CardContent>
              </Card>
            ))
          )}
        </div>
      ) : (
        <div className="grid grid-cols-7 gap-2">
          {days.map((day) => {
            const key = day.format("YYYY-MM-DD");
            return (
              <div
                key={key}
                className="min-h-[120px] rounded-xl border border-[var(--border)] bg-[var(--surface)] p-2"
                onDragOver={(event) => event.preventDefault()}
                onDrop={(event) => {
                  const id = event.dataTransfer.getData("text/content-id");
                  if (id) reschedule.mutate({ id, scheduled_at: `${key}T10:00:00` });
                }}
              >
                <p className="mb-2 text-xs text-[var(--muted)]">{day.format("D MMM")}</p>
                <div className="space-y-1">
                  {(byDay.get(key) ?? []).map((item) => (
                    <button
                      key={String(item.id)}
                      type="button"
                      draggable
                      onDragStart={(event) => event.dataTransfer.setData("text/content-id", String(item.id))}
                      className="block w-full rounded-lg bg-[var(--surface-muted)] px-2 py-1 text-right text-xs"
                    >
                      {String(item.title || "محتوا")}
                    </button>
                  ))}
                </div>
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
};

export default WorkspaceContentCalendar;