// Pure schedule/conflict helpers (moved from index.js — do not add db or http deps).


// ============================================
// HELPER FUNCTIONS
// ============================================

/**
 * Calculate departure times for each stop in a route
 * Returns array of { order, stopName, departureTime }
 */
function calculateDepartureTimes(startTime, busLineId, mock) {
  const startDate = new Date(startTime);

  // Get route stops for this bus line
  const routeStops = mock.routeStops
    .filter((rs) => rs.busLineId === busLineId)
    .sort((a, b) => a.stopOrder - b.stopOrder);

  return routeStops.map((rs) => {
    const departureDate = new Date(startDate);
    // Add estimated arrival minutes to get departure time
    departureDate.setMinutes(
      departureDate.getMinutes() + (rs.estimatedArrivalMinutes || 0),
    );

    const stop = mock.stops.find((s) => s.id === rs.stopId);
    return {
      order: rs.stopOrder,
      stopId: rs.stopId,
      stopName: stop?.name || "Unknown Stop",
      estimatedArrivalMinutes: rs.estimatedArrivalMinutes || 0,
      departureTime: departureDate.toISOString(),
    };
  });
}


function parseWeekdaysValue(value) {
  if (!value) return [];
  if (Array.isArray(value))
    return value.map((v) => Number(v)).filter((v) => Number.isFinite(v));

  if (typeof value === "string") {
    const trimmed = value.trim();
    if (!trimmed) return [];

    try {
      const parsed = JSON.parse(trimmed);
      if (Array.isArray(parsed)) {
        return parsed.map((v) => Number(v)).filter((v) => Number.isFinite(v));
      }
    } catch (_) {
      // Fall through to CSV/PG-array parsing.
    }

    // Handles values like "1,2,3" or "{1,2,3}".
    const normalized = trimmed.replace("{", "").replace("}", "");
    return normalized
      .split(",")
      .map((v) => Number(v.trim()))
      .filter((v) => Number.isFinite(v));
  }

  return [];
}


function toNumberOrNull(value) {
  if (value === undefined || value === null || value === "") return null;
  const numberValue = Number(value);
  return Number.isFinite(numberValue) ? numberValue : null;
}


function parseCommaSeparatedValues(value) {
  if (!value && value !== 0) return [];
  if (Array.isArray(value)) {
    return value.map((item) => String(item).trim()).filter(Boolean);
  }

  return String(value)
    .split(",")
    .map((item) => item.trim())
    .filter(Boolean);
}


function toDateKey(value) {
  if (!value) return null;
  const date = new Date(value);
  if (Number.isNaN(date.getTime())) return null;
  return date.toISOString().slice(0, 10);
}


function expandRecurringScheduleRows(rows) {
  const expandedRows = [];

  for (const row of rows) {
    const weekdays = parseWeekdaysValue(row.weekdays);
    if (!weekdays || weekdays.length === 0) {
      expandedRows.push(row);
      continue;
    }

    const templateDate = new Date(row.start_time);
    if (Number.isNaN(templateDate.getTime())) {
      expandedRows.push(row);
      continue;
    }

    const templateDayOfWeek = templateDate.getDay();
    const sortedWeekdays = [...new Set(weekdays)].sort((a, b) => a - b);
    const durationMinutes = Number(
      row.estimated_duration_minutes ?? row.estimatedDurationMinutes ?? 60,
    );

    for (let week = 0; week < 52; week++) {
      for (const targetWeekday of sortedWeekdays) {
        const daysOffset = (targetWeekday - templateDayOfWeek + 7) % 7;
        const totalDays = week * 7 + daysOffset;

        const scheduleDate = new Date(templateDate);
        scheduleDate.setDate(scheduleDate.getDate() + totalDays);

        const endDate = new Date(scheduleDate);
        endDate.setMinutes(endDate.getMinutes() + durationMinutes);

        expandedRows.push({
          ...row,
          start_time: scheduleDate.toISOString(),
          end_time: endDate.toISOString(),
          is_recurring_instance: true,
          template_id: row.id,
        });
      }
    }
  }

  return expandedRows;
}


function mapAdminScheduleRow(row, routeStopsByLine = new Map()) {
  const weekdays = parseWeekdaysValue(row.weekdays);
  const busLineId = Number(row.busLineId ?? row.bus_line_id);
  const startTime = row.startTime ?? row.start_time;
  const routeStops = routeStopsByLine.get(busLineId) || [];
  const departureTimes = buildDepartureTimes(startTime, routeStops);

  return {
    id: Number(row.id),
    busLineId,
    busId: Number(row.busId ?? row.bus_id),
    driverId:
      row.driverId !== null && row.driverId !== undefined
        ? Number(row.driverId)
        : null,
    driverName: row.driverName ?? row.driver_name ?? null,
    startTime,
    endTime: row.endTime ?? row.end_time,
    weekdays,
    departureTimes,
    status: row.status,
    lineNumber: Number(row.lineNumber ?? row.line_number) || null,
    busName: row.busName ?? row.bus_name ?? "Unknown Bus",
    licensePlate: row.licensePlate ?? row.license_plate ?? null,
    createdAt: row.createdAt ?? row.created_at ?? null,
    isRecurringInstance: row.is_recurring_instance || false,
    templateId: row.template_id || row.templateId || null,
    recurrenceLabel: formatWeekdayLabel(weekdays),
    isRecurring: weekdays.length > 0,
  };
}


function scheduleMatchesFilters(
  schedule,
  filters,
  routeStopsByLine = new Map(),
) {
  if (!schedule || !filters) return true;

  const scheduleBusLineId = Number(schedule.bus_line_id ?? schedule.busLineId);
  const scheduleBusId = Number(schedule.bus_id ?? schedule.busId);
  const scheduleDriverId = Number(schedule.driver_id ?? schedule.driverId);
  const scheduleStatus = String(schedule.status || "");
  const scheduleDateKey = toDateKey(schedule.start_time ?? schedule.startTime);

  if (filters.busLineId !== null && scheduleBusLineId !== filters.busLineId) {
    return false;
  }

  if (filters.busId !== null && scheduleBusId !== filters.busId) {
    return false;
  }

  if (filters.driverId !== null && scheduleDriverId !== filters.driverId) {
    return false;
  }

  if (
    filters.statuses.length > 0 &&
    !filters.statuses.includes(scheduleStatus)
  ) {
    return false;
  }

  if (filters.date && scheduleDateKey !== filters.date) {
    return false;
  }

  if (
    filters.fromDate &&
    scheduleDateKey &&
    scheduleDateKey < filters.fromDate
  ) {
    return false;
  }

  if (filters.toDate && scheduleDateKey && scheduleDateKey > filters.toDate) {
    return false;
  }

  if (filters.stopId !== null) {
    const routeStops = routeStopsByLine.get(scheduleBusLineId) || [];
    const matchesStop = routeStops.some(
      (routeStop) =>
        Number(routeStop.stop_id ?? routeStop.stopId) === filters.stopId,
    );
    if (!matchesStop) {
      return false;
    }
  }

  return true;
}


function parseScheduleFilters(query, options = {}) {
  const statuses = parseCommaSeparatedValues(
    query.status || query.statuses || options.statuses || [],
  );

  return {
    date: query.date ? String(query.date).trim() : null,
    fromDate: query.fromDate ? String(query.fromDate).trim() : null,
    toDate: query.toDate ? String(query.toDate).trim() : null,
    driverId: toNumberOrNull(
      query.driverId ??
        query.driver_id ??
        query.chauffeurId ??
        query.chauffeur_id,
    ),
    busId: toNumberOrNull(query.busId ?? query.bus_id),
    busLineId: toNumberOrNull(
      query.busLineId ?? query.lineId ?? query.bus_line_id,
    ),
    stopId: toNumberOrNull(
      query.stopId ?? query.stop_id ?? query.busStopId ?? query.bus_stop_id,
    ),
    statuses,
  };
}


function formatWeekdayLabel(weekdays) {
  const labels = ["Zo", "Ma", "Di", "Wo", "Do", "Vr", "Za"];

  if (!Array.isArray(weekdays) || weekdays.length === 0) {
    return "Eenmalig";
  }

  if (weekdays.length === 7) {
    return "Dagelijks";
  }

  return [...new Set(weekdays)]
    .sort((a, b) => a - b)
    .filter((day) => day >= 0 && day < labels.length)
    .map((day) => labels[day])
    .join(", ");
}


function buildDepartureTimes(startTime, routeStops = []) {
  const startDate = new Date(startTime);

  return routeStops.map((routeStop) => {
    const departureDate = new Date(startDate);
    const etaMinutes =
      Number(
        routeStop.estimated_arrival_minutes ??
          routeStop.estimatedArrivalMinutes,
      ) || 0;
    departureDate.setMinutes(departureDate.getMinutes() + etaMinutes);

    return {
      order: Number(routeStop.stop_order ?? routeStop.stopOrder),
      stopId: Number(routeStop.stop_id ?? routeStop.stopId),
      stopName: routeStop.stop_name || routeStop.name || "Unknown Stop",
      estimatedArrivalMinutes: etaMinutes,
      departureTime: departureDate.toISOString(),
    };
  });
}


function isRecurringSchedule(schedule) {
  return parseWeekdaysValue(schedule.weekdays).length > 0;
}


function scheduleOccursOnDate(schedule, dateKey) {
  if (!dateKey) return true;

  const weekdays = parseWeekdaysValue(schedule.weekdays);
  const scheduleDateKey = toDateKey(schedule.start_time ?? schedule.startTime);

  if (!scheduleDateKey) {
    return false;
  }

  if (weekdays.length === 0) {
    return scheduleDateKey === dateKey;
  }

  if (scheduleDateKey > dateKey) {
    return false;
  }

  const targetDate = new Date(`${dateKey}T00:00:00`);
  return weekdays.includes(targetDate.getDay());
}


function materializeScheduleOverviewRow(
  row,
  dateKey,
  routeStopsByLine = new Map(),
) {
  const weekdays = parseWeekdaysValue(row.weekdays);
  const recurring = weekdays.length > 0;
  const templateStart = new Date(row.startTime ?? row.start_time);
  const templateEnd = new Date(row.endTime ?? row.end_time);
  let startTime = row.startTime ?? row.start_time;
  let endTime = row.endTime ?? row.end_time;

  if (recurring && dateKey) {
    const occurrenceStart = new Date(`${dateKey}T00:00:00`);
    occurrenceStart.setHours(
      templateStart.getHours(),
      templateStart.getMinutes(),
      templateStart.getSeconds(),
      templateStart.getMilliseconds(),
    );

    startTime = occurrenceStart.toISOString();

    if (
      Number.isFinite(templateEnd.getTime()) &&
      Number.isFinite(templateStart.getTime())
    ) {
      const durationMillis = templateEnd.getTime() - templateStart.getTime();
      const occurrenceEnd = new Date(occurrenceStart);
      occurrenceEnd.setMilliseconds(
        occurrenceEnd.getMilliseconds() + durationMillis,
      );
      endTime = occurrenceEnd.toISOString();
    }
  }

  const busLineId = Number(row.busLineId ?? row.bus_line_id);
  const routeStops = routeStopsByLine.get(busLineId) || [];
  const departureTimes = buildDepartureTimes(startTime, routeStops);

  return {
    id: Number(row.id),
    busLineId,
    busId: Number(row.busId ?? row.bus_id),
    // Hide driver information in public schedule materialization for privacy
    driverId: null,
    driverName: null,
    startTime,
    endTime,
    weekdays,
    status: row.status,
    lineNumber: Number(row.lineNumber ?? row.line_number) || null,
    busName: row.busName ?? row.bus_name ?? "Unknown Bus",
    licensePlate: row.licensePlate ?? row.license_plate ?? null,
    createdAt: row.createdAt ?? row.created_at ?? null,
    scheduleType: recurring ? "recurring" : "one_time",
    recurrenceLabel: formatWeekdayLabel(weekdays),
    isRecurringInstance: recurring && Boolean(dateKey),
    templateId: row.templateId ?? row.template_id ?? null,
    departureTimes,
  };
}


function mapRecurringOccurrenceRows(rows, dateKey, routeStopsByLine) {
  return rows
    .filter((row) => scheduleOccursOnDate(row, dateKey))
    .map((row) =>
      materializeScheduleOverviewRow(row, dateKey, routeStopsByLine),
    )
    .sort((a, b) => new Date(a.startTime) - new Date(b.startTime));
}


function materializeScheduleRowsInRange(
  rows,
  fromDateKey,
  toDateKey,
  routeStopsByLine,
) {
  const occurrences = [];
  if (!fromDateKey || !toDateKey) return occurrences;

  const fromDate = new Date(`${fromDateKey}T00:00:00`);
  const toDate = new Date(`${toDateKey}T23:59:59`);

  // Safety cap: don't generate more than 366 days
  const maxDays = 366;
  const spanDays = Math.ceil((toDate - fromDate) / (24 * 60 * 60 * 1000));
  if (spanDays > maxDays) return occurrences;

  for (const row of rows) {
    const weekdays = parseWeekdaysValue(row.weekdays);

    if (!weekdays || weekdays.length === 0) {
      const rowDateKey = toDateKey(row.start_time ?? row.startTime);
      if (rowDateKey && rowDateKey >= fromDateKey && rowDateKey <= toDateKey) {
        occurrences.push(
          materializeScheduleOverviewRow(row, rowDateKey, routeStopsByLine),
        );
      }
      continue;
    }

    // recurring template: generate occurrences per weekday within range
    const templateStart = new Date(row.start_time ?? row.startTime);
    for (const wd of [...new Set(weekdays)]) {
      // find first date >= fromDate that matches weekday wd and is >= templateStart
      let cursor = new Date(fromDate);
      const fromWeekday = cursor.getDay();
      const daysOffset = (wd - fromWeekday + 7) % 7;
      cursor.setDate(cursor.getDate() + daysOffset);

      // ensure cursor >= templateStart (so recurrence doesn't start before template)
      if (cursor < templateStart) {
        // advance by weeks until >= templateStart
        const diffDays = Math.ceil(
          (templateStart - cursor) / (24 * 60 * 60 * 1000),
        );
        const weeksToAdvance = Math.ceil(diffDays / 7);
        cursor.setDate(cursor.getDate() + weeksToAdvance * 7);
      }

      while (cursor <= toDate) {
        const occurrenceKey = cursor.toISOString().slice(0, 10);
        occurrences.push(
          materializeScheduleOverviewRow(row, occurrenceKey, routeStopsByLine),
        );
        cursor.setDate(cursor.getDate() + 7);
      }
    }
  }

  // sort and return
  return occurrences.sort(
    (a, b) => new Date(a.startTime) - new Date(b.startTime),
  );
}


/**
 * Check if two schedules have date/weekday overlap
 */
function doSchedulesDateOverlap(
  schedule1Start,
  schedule1End,
  schedule1Weekdays,
  schedule2Start,
  schedule2End,
  schedule2Weekdays,
) {
  const s1Start = new Date(schedule1Start);
  const s1End = new Date(schedule1End);
  const s2Start = new Date(schedule2Start);
  const s2End = new Date(schedule2End);

  // Check time overlap
  if (s1End <= s2Start || s2End <= s1Start) {
    return false; // No time overlap
  }

  // If both have no weekdays (one-time), check if same day
  if (
    (!schedule1Weekdays || schedule1Weekdays.length === 0) &&
    (!schedule2Weekdays || schedule2Weekdays.length === 0)
  ) {
    return s1Start.toDateString() === s2Start.toDateString();
  }

  // If one has weekdays and other doesn't, check if one-time falls on weekday
  if (
    schedule1Weekdays &&
    schedule1Weekdays.length > 0 &&
    (!schedule2Weekdays || schedule2Weekdays.length === 0)
  ) {
    const s2Day = s2Start.getDay(); // 0=Sun, 1=Mon, etc.
    const s2Adjusted = s2Day === 0 ? 0 : s2Day; // Normalize to 0-6
    return schedule1Weekdays.includes(s2Adjusted);
  }

  if (
    (!schedule1Weekdays || schedule1Weekdays.length === 0) &&
    schedule2Weekdays &&
    schedule2Weekdays.length > 0
  ) {
    const s1Day = s1Start.getDay();
    const s1Adjusted = s1Day === 0 ? 0 : s1Day;
    return schedule2Weekdays.includes(s1Adjusted);
  }

  // Both have weekdays: check if any day overlaps
  if (schedule1Weekdays && schedule2Weekdays) {
    return schedule1Weekdays.some((d) => schedule2Weekdays.includes(d));
  }

  return false;
}


/**
 * Check if a driver has conflicts with existing schedules
 */
function checkDriverConflict(
  driverId,
  startTime,
  endTime,
  weekdays,
  allSchedules,
  excludeScheduleId = null,
) {
  if (!driverId) return false; // No conflict if no driver specified

  return allSchedules.some((s) => {
    if (excludeScheduleId && s.id === excludeScheduleId) return false;
    const sDriverId = s.driverId ?? s.driver_id;
    if (Number(sDriverId) !== Number(driverId)) return false;

    const sWeekdays = parseWeekdaysValue(s.weekdays);
    const wkdays = weekdays || [];
    const sStart = s.startTime ?? s.start_time;
    const sEnd = s.endTime ?? s.end_time;

    return doSchedulesDateOverlap(
      startTime,
      endTime,
      wkdays,
      sStart,
      sEnd,
      sWeekdays,
    );
  });
}


/**
 * Check if a bus has conflicts with existing schedules
 */
function checkBusConflict(
  busId,
  startTime,
  endTime,
  weekdays,
  allSchedules,
  excludeScheduleId = null,
) {
  if (!busId) return false;

  return allSchedules.some((s) => {
    if (excludeScheduleId && s.id === excludeScheduleId) return false;
    const sBusId = s.busId ?? s.bus_id;
    if (Number(sBusId) !== Number(busId)) return false;

    const sWeekdays = parseWeekdaysValue(s.weekdays);
    const wkdays = weekdays || [];
    const sStart = s.startTime ?? s.start_time;
    const sEnd = s.endTime ?? s.end_time;

    return doSchedulesDateOverlap(
      startTime,
      endTime,
      wkdays,
      sStart,
      sEnd,
      sWeekdays,
    );
  });
}

module.exports = { calculateDepartureTimes, parseWeekdaysValue, toNumberOrNull, parseCommaSeparatedValues, toDateKey, expandRecurringScheduleRows, mapAdminScheduleRow, scheduleMatchesFilters, parseScheduleFilters, formatWeekdayLabel, buildDepartureTimes, isRecurringSchedule, scheduleOccursOnDate, materializeScheduleOverviewRow, mapRecurringOccurrenceRows, materializeScheduleRowsInRange, doSchedulesDateOverlap, checkDriverConflict, checkBusConflict };