import type { AlertEvent, AlertRule, AlertSeverity, AlertStatus } from '../../api/types';
import { formatZhNumber } from './formatters';

const alertTimeFormatter = new Intl.DateTimeFormat('zh-CN', {
  month: '2-digit',
  day: '2-digit',
  hour: '2-digit',
  minute: '2-digit',
  second: '2-digit',
  hour12: false,
  timeZone: 'Asia/Shanghai'
});

export const severityLabels: Record<AlertSeverity, string> = { critical: '紧急', major: '重要', minor: '一般' };
export const statusLabels: Record<AlertStatus, string> = { unprocessed: '未处理', processing: '处理中', recovered: '已恢复', closed: '已关闭', ignored: '已忽略' };
export const actionLabels: Record<string, string> = { trigger: '触发', acknowledge: '已确认', close: '已关闭', ignore: '已忽略', recover: '已恢复', processing: '处理中', recovered: '已恢复', closed: '已关闭', ignored: '已忽略' };
export const metricLabels: Record<string, string> = { speed_kmh: '速度', soc_percent: 'SOC', alarm_active: '协议告警位', freshness_sec: '离线时长', data_delay_sec: '数据延迟' };
export const operatorLabels: Record<string, string> = { gt: '>', gte: '≥', lt: '<', lte: '≤', eq: '=', neq: '≠', between: '区间内', outside: '区间外', changed: '状态变化' };

export function formatAlertTime(value: string) {
  if (!value) return '—';
  const date = new Date(value);
  if (Number.isNaN(date.getTime())) return value.replace('T', ' ').slice(0, 19);
  return alertTimeFormatter.format(date).replace(/\//g, '-');
}

export function alertValue(event: Pick<AlertEvent, 'triggerValue' | 'unit'>) {
  return `${formatZhNumber(Number(event.triggerValue.toFixed(2)), 2)} ${event.unit}`.trim();
}

export function thresholdText(event: Pick<AlertEvent, 'operator' | 'threshold' | 'thresholdHigh' | 'unit' | 'durationSec'>) {
  const duration = event.durationSec > 0 ? `，持续 ${event.durationSec} 秒` : '';
  if (event.operator === 'between' || event.operator === 'outside') return `${operatorLabels[event.operator]} ${event.threshold}–${event.thresholdHigh} ${event.unit}${duration}`.trim();
  if (event.operator === 'changed') return `状态发生变化${duration}`;
  return `${operatorLabels[event.operator] ?? event.operator} ${formatZhNumber(Number(event.threshold.toFixed(2)), 2)} ${event.unit}${duration}`.trim();
}

export function alertDeltaText(event: Pick<AlertEvent, 'operator' | 'triggerValue' | 'threshold' | 'unit'>) {
  if (!Number.isFinite(event.triggerValue) || !Number.isFinite(event.threshold)) return '规则已命中';
  const delta = event.operator === 'gt' || event.operator === 'gte'
    ? event.triggerValue - event.threshold
    : event.operator === 'lt' || event.operator === 'lte'
      ? event.threshold - event.triggerValue
      : Number.NaN;
  if (!Number.isFinite(delta)) return '规则已命中';
  return `+${formatZhNumber(Number(Math.max(0, delta).toFixed(2)), 2)} ${event.unit}`.trim();
}

export function ruleCondition(rule: AlertRule, labels: Record<string, string> = metricLabels) {
  const threshold = rule.operator === 'changed' ? '状态变化' : rule.operator === 'between' || rule.operator === 'outside' ? `${operatorLabels[rule.operator]} ${rule.threshold}–${rule.thresholdHigh}` : rule.valueType === 'boolean' ? (rule.booleanThreshold ? '是' : '否') : `${operatorLabels[rule.operator] ?? rule.operator} ${rule.threshold}`;
  return `${labels[rule.metric] ?? rule.metric} ${threshold}${rule.durationSec ? ` · ${rule.durationSec} 秒` : ''}`;
}

export function canAct(status: AlertStatus, action: 'acknowledge' | 'close' | 'ignore') {
  if (action === 'acknowledge') return status === 'unprocessed';
  if (action === 'close') return status === 'unprocessed' || status === 'processing' || status === 'recovered';
  return status === 'unprocessed' || status === 'processing';
}