import { compactWeekLabel } from "@/domain/work-orders/utils/list-week-utils";
import { formatRescheduleCountLabel } from "@/domain/work-orders/utils/reschedule-indicator";
import { deriveDayFields } from "@/domain/work-orders/utils/table-day-utils";
import { addDaysIso, mondayOf } from "@/domain/work-orders/utils/wizard-date-utils";

const ISO_DATE = /^\d{4}-\d{2}-\d{2}$/;
const WEEKDAY_COUNT = 7;
const FRIDAY_OFFSET = 4;

export type CarryOverRow = {
  scheduledOn: string;
  status?: string;
  carriedOver?: number;
};

export function isTerminalCarryOverStatus(status?: string): boolean {
  return status === "Completed" || status === "Canceled";
}

export function shouldShowCarriedOverPill(count: number, status?: string): boolean {
  return count >= 2 && !isTerminalCarryOverStatus(status);
}

export function toIsoDate(value?: string): string {
  if (!value) {
    return "";
  }
  const iso = value.slice(0, 10);
  return ISO_DATE.test(iso) ? iso : "";
}

export function resolveCarryOverSourceWeek(input: {
  originalWeek?: string;
  originalDate?: string;
  scheduledOn?: string;
}): string {
  const originalWeek = toIsoDate(input.originalWeek);
  if (originalWeek) {
    return mondayOf(originalWeek);
  }
  const originalDate = toIsoDate(input.originalDate);
  if (originalDate) {
    return mondayOf(originalDate);
  }
  const scheduledOn = toIsoDate(input.scheduledOn);
  return scheduledOn ? mondayOf(scheduledOn) : "";
}

export function formatCarriedOverHover(count: number, sourceWeekIso?: string): string {
  const times = formatRescheduleCountLabel(count);
  const base = `Carried over ${times} — this WO was not completed and moved to the next period`;
  const sourceLabel = sourceWeekIso ? compactWeekLabel(sourceWeekIso) : "";
  if (!sourceLabel) {
    return base;
  }
  return `${base}. Source week: ${sourceLabel}.`;
}

/** Non-terminal WOs scheduled before the viewed week are display carry-overs. */
export function isCarryOverDisplayRow(row: CarryOverRow, weekMonday: string): boolean {
  if (isTerminalCarryOverStatus(row.status)) {
    return false;
  }
  const scheduled = toIsoDate(row.scheduledOn);
  return Boolean(scheduled) && scheduled < weekMonday;
}

export function mapCarryOverDisplayDay(scheduledOn: string, weekMonday: string): string {
  const scheduled = toIsoDate(scheduledOn);
  if (!scheduled || !ISO_DATE.test(weekMonday)) {
    return "";
  }
  const sourceMonday = mondayOf(scheduled);
  const offsetMs =
    new Date(`${scheduled}T12:00:00`).getTime() - new Date(`${sourceMonday}T12:00:00`).getTime();
  const offset = Math.round(offsetMs / 86_400_000);
  if (offset < 0 || offset >= WEEKDAY_COUNT) {
    return weekMonday;
  }
  if (offset > FRIDAY_OFFSET) {
    return weekMonday;
  }
  return addDaysIso(weekMonday, offset);
}

export function rowMatchesCarryOverDay(
  row: CarryOverRow,
  selectedDayIso: string,
  weekMonday: string,
): boolean {
  if (!isCarryOverDisplayRow(row, weekMonday)) {
    return false;
  }
  return mapCarryOverDisplayDay(row.scheduledOn, weekMonday) === selectedDayIso;
}

/** Aligns UI day keys with the mapped weekday so reorder stays on the displayed tab. */
export function applyCarryOverDisplayDayFields<
  T extends CarryOverRow & { dayGroup: string; dayLabel: string },
>(row: T, weekMonday: string): T {
  if (!isCarryOverDisplayRow(row, weekMonday)) {
    return row;
  }
  const displayDay = mapCarryOverDisplayDay(row.scheduledOn, weekMonday);
  if (!displayDay) {
    return row;
  }
  return { ...row, ...deriveDayFields(displayDay) };
}