/**
 * 차트 하단 시간축·크로스헤어 시간 표시 포맷 (앱 설정 chartTimeFormat).
 */
import { useSyncExternalStore } from 'react';
import { TickMarkType, type Time } from 'lightweight-charts';
import type { Timeframe } from '../types';
import { getDisplayTimezone, normalizeTimezone } from './timezone';

export const DEFAULT_CHART_TIME_FORMAT = 'MM-dd HH:mm';

export interface ChartTimeFormatPreset {
  id: string;
  label: string;
}

/** 통상적인 차트 시간축 프리셋 (일반설정·차트 설정 공통) */
export const CHART_TIME_FORMAT_PRESETS: ChartTimeFormatPreset[] = [
  { id: 'yyyy-MM-dd HH:mm:ss', label: 'yyyy-MM-dd HH:mm:ss' },
  { id: 'yyyy-MM-dd HH:mm',    label: 'yyyy-MM-dd HH:mm' },
  { id: 'yyyy-MM-dd',          label: 'yyyy-MM-dd' },
  { id: 'yyyy/MM/dd HH:mm:ss', label: 'yyyy/MM/dd HH:mm:ss' },
  { id: 'yyyy/MM/dd HH:mm',    label: 'yyyy/MM/dd HH:mm' },
  { id: 'MM-dd HH:mm:ss',      label: 'MM-dd HH:mm:ss' },
  { id: 'MM-dd HH:mm',         label: 'MM-dd HH:mm' },
  { id: 'MM/dd/yyyy HH:mm:ss', label: 'MM/dd/yyyy HH:mm:ss' },
  { id: 'MM/dd/yyyy HH:mm',    label: 'MM/dd/yyyy HH:mm' },
  { id: 'dd/MM/yyyy HH:mm:ss', label: 'dd/MM/yyyy HH:mm:ss' },
  { id: 'dd/MM/yyyy HH:mm',    label: 'dd/MM/yyyy HH:mm' },
  { id: 'dd/MM HH:mm:ss',      label: 'dd/MM HH:mm:ss' },
  { id: 'dd/MM HH:mm',         label: 'dd/MM HH:mm' },
  { id: 'dd-MM HH:mm:ss',      label: 'dd-MM HH:mm:ss' },
  { id: 'dd-MM HH:mm',         label: 'dd-MM HH:mm' },
  { id: 'dd.MM.yyyy HH:mm:ss', label: 'dd.MM.yyyy HH:mm:ss' },
  { id: 'dd.MM.yyyy HH:mm',    label: 'dd.MM.yyyy HH:mm' },
  { id: 'HH:mm:ss',            label: 'HH:mm:ss' },
  { id: 'HH:mm',               label: 'HH:mm' },
];

const PRESET_IDS = new Set(CHART_TIME_FORMAT_PRESETS.map(p => p.id));

let _format = DEFAULT_CHART_TIME_FORMAT;
const _listeners = new Set<() => void>();

export function getChartTimeFormat(): string {
  return _format;
}

export function setChartTimeFormat(format: string): void {
  const next = normalizeChartTimeFormat(format);
  if (_format === next) return;
  _format = next;
  _listeners.forEach(l => l());
}

export function subscribeChartTimeFormat(cb: () => void): () => void {
  _listeners.add(cb);
  return () => _listeners.delete(cb);
}

export function useChartTimeFormat(): string {
  return useSyncExternalStore(
    subscribeChartTimeFormat,
    getChartTimeFormat,
    () => DEFAULT_CHART_TIME_FORMAT,
  );
}

/** 허용 토큰: yyyy yy MM dd HH mm ss */
export function normalizeChartTimeFormat(format: string): string {
  const t = (format || '').trim();
  if (!t) return DEFAULT_CHART_TIME_FORMAT;
  if (!/[yMdHms]/.test(t)) return DEFAULT_CHART_TIME_FORMAT;
  return t.slice(0, 64);
}

export function isPresetChartTimeFormat(format: string): boolean {
  return PRESET_IDS.has(normalizeChartTimeFormat(format));
}

interface ZonedParts {
  yyyy: string;
  yy: string;
  MM: string;
  dd: string;
  HH: string;
  mm: string;
  ss: string;
}

function getZonedParts(unixSec: number, tz: string): ZonedParts {
  const d = new Date(unixSec * 1000);
  const zone = normalizeTimezone(tz);
  const parts = new Intl.DateTimeFormat('en-GB', {
    timeZone: zone,
    year: 'numeric',
    month: '2-digit',
    day: '2-digit',
    hour: '2-digit',
    minute: '2-digit',
    second: '2-digit',
    hour12: false,
  }).formatToParts(d);
  const map: Record<string, string> = {};
  for (const p of parts) {
    if (p.type !== 'literal') map[p.type] = p.value;
  }
  const year = map.year ?? '';
  return {
    yyyy: year,
    yy: year.slice(-2),
    MM: map.month ?? '',
    dd: map.day ?? '',
    HH: map.hour ?? '',
    mm: map.minute ?? '',
    ss: map.second ?? '',
  };
}

const TOKEN_ORDER = ['yyyy', 'yy', 'MM', 'dd', 'HH', 'mm', 'ss'] as const;

export function applyChartTimePattern(pattern: string, parts: ZonedParts): string {
  let out = normalizeChartTimeFormat(pattern);
  for (const tok of TOKEN_ORDER) {
    out = out.split(tok).join(parts[tok]);
  }
  return out;
}

function patternHasDate(pattern: string): boolean {
  return /yyyy|yy|MM|dd/.test(pattern);
}

function patternHasTime(pattern: string): boolean {
  return /HH|mm|ss/.test(pattern);
}

/** 패턴에서 날짜·시간 부분 분리 (눈금 타입별 표시용) */
export function splitChartTimePattern(pattern: string): { date: string; time: string } {
  const p = normalizeChartTimeFormat(pattern);
  if (!patternHasTime(p)) return { date: p, time: '' };
  if (!patternHasDate(p)) return { date: '', time: p };

  const timeIdx = p.search(/HH|mm|ss/);
  if (timeIdx < 0) return { date: p, time: '' };

  return {
    date: p.slice(0, timeIdx).trim(),
    time: p.slice(timeIdx).trim(),
  };
}

function isDailyTimeframe(tf?: string): boolean {
  return tf === '1D' || tf === '1W' || tf === '1M';
}

/** unix 초 → 사용자 지정 포맷 */
export function formatUnixWithChartPattern(
  unixSec: number,
  pattern?: string,
  tz?: string,
): string {
  if (!unixSec) return '';
  const zone = normalizeTimezone(tz ?? getDisplayTimezone());
  const parts = getZonedParts(unixSec, zone);
  return applyChartTimePattern(pattern ?? _format, parts);
}

/** LWC 크로스헤어·timeFormatter */
export function formatLwcTimeWithPattern(
  time: number | { year: number; month: number; day: number },
  timeframe?: Timeframe,
  tz?: string,
  pattern?: string,
): string {
  const fmt = pattern ?? _format;
  const zone = normalizeTimezone(tz ?? getDisplayTimezone());
  if (typeof time === 'number') {
    if (isDailyTimeframe(timeframe) && !patternHasTime(fmt)) {
      return formatUnixWithChartPattern(time, fmt, zone);
    }
    return formatUnixWithChartPattern(time, fmt, zone);
  }
  const unix = Math.floor(Date.UTC(time.year, time.month - 1, time.day) / 1000);
  return formatUnixWithChartPattern(unix, fmt, zone);
}

/** LWC X축 눈금 */
export function formatLwcTickMarkWithPattern(
  time: Time,
  tickMarkType: TickMarkType,
  timeframe?: Timeframe,
  tz?: string,
  pattern?: string,
): string {
  const fmt = normalizeChartTimeFormat(pattern ?? _format);
  const zone = normalizeTimezone(tz ?? getDisplayTimezone());
  const unixSec = typeof time === 'number'
    ? time
    : time && typeof time === 'object' && 'year' in time
      ? Math.floor(Date.UTC(time.year, time.month - 1, time.day) / 1000)
      : null;
  if (unixSec == null) return '';
  const parts = getZonedParts(unixSec, zone);
  const { date: datePat, time: timePat } = splitChartTimePattern(fmt);

  switch (tickMarkType) {
    case TickMarkType.Year:
      return parts.yyyy || applyChartTimePattern('yyyy', parts);
    case TickMarkType.Month:
      if (datePat.includes('MM')) return applyChartTimePattern(datePat.includes('yyyy') ? 'yyyy-MM' : 'MM', parts);
      return new Intl.DateTimeFormat('en-GB', { timeZone: zone, month: 'short' }).format(new Date(unixSec * 1000));
    case TickMarkType.DayOfMonth:
      if (isDailyTimeframe(timeframe) || !patternHasTime(fmt)) {
        return datePat ? applyChartTimePattern(datePat, parts) : parts.dd;
      }
      return datePat ? applyChartTimePattern(datePat, parts) : parts.dd;
    case TickMarkType.Time:
      return timePat ? applyChartTimePattern(timePat.replace(/ss/g, ''), parts) : `${parts.HH}:${parts.mm}`;
    case TickMarkType.TimeWithSeconds:
      return timePat ? applyChartTimePattern(timePat, parts) : `${parts.HH}:${parts.mm}:${parts.ss}`;
    default:
      return formatUnixWithChartPattern(unixSec, fmt, zone);
  }
}