"use client";

/**
 * 考勤点名表页 - 客户端组件（ARCHITECTURE.md §7.3 表单页 / §9.1 / §10 P2）
 *
 * 数据契约：
 * - 查询 attendanceSheet(classId, date)：❌ schema 无此字段 → MSW 兜底（@contract-pending）
 * - mutation saveAttendanceSheet(input)：❌ schema 无 Mutation → MSW 兜底（@contract-pending）
 * - 契约工单：docs/architecture/issues/contracts/classes_contract.md#attendance-sheet
 *
 * 三态规范（§11.3 DoD）：
 * - loading：FormPageSkeleton（由 server page Suspense 兜底）
 * - error：errorSummary 表单级错误
 * - success：notify.success + 刷新列表
 *
 * 关联：ARCHITECTURE.md §5.3 / §5.4 / §7.3 / §9.1 / §10 P2 / §11.3 / §11.4
 */
import { ClipboardCheck } from "lucide-react";
import { useRouter, useSearchParams } from "next/navigation";
import { useEffect, useTransition, useState } from "react";
import { useTranslations } from "next-intl";

import {
  ATTENDANCE_STATUS,
  useAttendanceSheet,
  useSaveAttendanceSheet,
  type AttendanceEntryInput,
} from "@/lib/api";
import { FormPageShell } from "@/shared/components/page-templates";
import { notify } from "@/shared/lib/notify";
import {
  attendanceStatusToBadgeClass,
  formatAttendanceStatus,
} from "@/features/teacher/attendance/transformations";

const STATUS_OPTIONS = [
  ATTENDANCE_STATUS.PRESENT,
  ATTENDANCE_STATUS.ABSENT,
  ATTENDANCE_STATUS.LATE,
  ATTENDANCE_STATUS.LEAVE,
];

/**
 * 表单客户端主体。需由 server page 包裹在 <Suspense> 中。
 */
export function AttendanceSheetClient(): React.ReactElement {
  const t = useTranslations("attendance");
  const router = useRouter();
  const searchParams = useSearchParams();
  const [, startTransition] = useTransition();

  const presetClassId = searchParams.get("classId") ?? "";
  const today = new Date().toISOString().slice(0, 10);
  const presetDate = searchParams.get("date") ?? today;

  const [classId, setClassId] = useState(presetClassId);
  const [date, setDate] = useState(presetDate);
  const [entries, setEntries] = useState<Record<string, AttendanceEntryInput>>(
    {},
  );
  const [submitting, setSubmitting] = useState(false);

  // @contract-pending：MSW 兜底
  const { data, loading, error } = useAttendanceSheet(classId, date, {
    enabled: classId.length > 0 && date.length > 0,
  });

  // 初始化 entries（首次加载数据后）
  useEffect(() => {
    if (!data) return;
    setEntries((prev) => {
      if (Object.keys(prev).length > 0) return prev;
      const next: Record<string, AttendanceEntryInput> = {};
      for (const e of data.entries) {
        next[e.studentId] = {
          studentId: e.studentId,
          status: e.status,
          remark: e.remark ?? undefined,
        };
      }
      return next;
    });
  }, [data]);

  const handleStatusChange = (studentId: string, status: string): void => {
    setEntries((prev) => ({
      ...prev,
      [studentId]: {
        studentId,
        status,
        remark: prev[studentId]?.remark,
      },
    }));
  };

  const { run: saveSheet } = useSaveAttendanceSheet();

  const handleSubmit = async (): Promise<void> => {
    if (!classId.trim()) {
      notify.error(t("sheet.errorClassRequired"));
      return;
    }
    if (!date) {
      notify.error(t("sheet.errorDateRequired"));
      return;
    }
    const entryList = Object.values(entries);
    if (entryList.length === 0) {
      notify.warning(t("sheet.errorNoEntries"));
      return;
    }
    setSubmitting(true);
    try {
      await saveSheet({ classId, date, entries: entryList });
      notify.success(t("sheet.success"));
      startTransition(() => {
        router.push(
          `/shell/teacher/attendance?classId=${classId}&date=${date}`,
        );
      });
    } catch (err) {
      notify.error(`${t("sheet.error")}: ${String(err)}`);
    } finally {
      setSubmitting(false);
    }
  };

  const errorSummary = error ? (
    <p className="text-sm text-destructive">
      {t("sheet.loadFailed", { message: String(error) })}
    </p>
  ) : undefined;

  return (
    <FormPageShell
      title={t("sheet.title")}
      description={t("sheet.description")}
      icon={<ClipboardCheck className="size-6" />}
      backHref="/shell/teacher/attendance"
      loading={loading && !data}
      submitting={submitting}
      submitLabel={t("sheet.submit")}
      cancelLabel={t("sheet.cancel")}
      errorSummary={errorSummary}
      onSubmit={handleSubmit}
    >
      <div className="space-y-4">
        <div className="grid grid-cols-2 gap-4">
          <label className="space-y-1">
            <span className="text-sm font-medium">{t("sheet.classId")}</span>
            <input
              type="text"
              value={classId}
              onChange={(e) => setClassId(e.target.value)}
              placeholder={t("sheet.classIdPlaceholder")}
              className="h-9 w-full rounded-md border border-input bg-background px-3 text-sm"
            />
          </label>
          <label className="space-y-1">
            <span className="text-sm font-medium">{t("sheet.date")}</span>
            <input
              type="date"
              value={date}
              onChange={(e) => setDate(e.target.value)}
              className="h-9 w-full rounded-md border border-input bg-background px-3 text-sm"
            />
          </label>
        </div>

        {data ? (
          <div className="space-y-3">
            <div className="rounded-xl border">
              <table className="w-full text-sm">
                <thead className="border-b bg-muted/30">
                  <tr>
                    <th className="p-3 text-left font-medium">
                      {t("sheet.colStudentName")}
                    </th>
                    <th className="p-3 text-left font-medium">
                      {t("sheet.colStatus")}
                    </th>
                    <th className="p-3 text-left font-medium">
                      {t("sheet.colRemark")}
                    </th>
                  </tr>
                </thead>
                <tbody className="divide-y">
                  {data.entries.map((entry) => {
                    const current = entries[entry.studentId];
                    const status = current?.status ?? entry.status;
                    return (
                      <tr key={entry.studentId}>
                        <td className="p-3 font-medium">{entry.studentName}</td>
                        <td className="p-3">
                          <div className="flex flex-wrap items-center gap-2">
                            {STATUS_OPTIONS.map((opt) => (
                              <button
                                key={opt}
                                type="button"
                                onClick={() =>
                                  handleStatusChange(entry.studentId, opt)
                                }
                                className={`inline-flex h-6 items-center rounded-full px-2 text-xs font-medium transition-opacity ${
                                  status === opt
                                    ? attendanceStatusToBadgeClass(opt)
                                    : "bg-muted text-muted-foreground opacity-50"
                                }`}
                                aria-pressed={status === opt}
                              >
                                {formatAttendanceStatus(opt)}
                              </button>
                            ))}
                          </div>
                        </td>
                        <td className="p-3 text-xs text-muted-foreground">
                          {current?.remark ?? entry.remark ?? "-"}
                        </td>
                      </tr>
                    );
                  })}
                </tbody>
              </table>
            </div>
            <p className="text-xs text-muted-foreground">
              {t("sheet.mswNotice")}
            </p>
          </div>
        ) : null}
      </div>
    </FormPageShell>
  );
}