import { LitElement, html, css } from 'lit';

class TimeRangePicker extends LitElement {
  static properties = {
    duration: { type: String },
    endTime: { type: Number },
    isLiveMode: { type: Boolean }
  };

  static durations = ['5m', '15m', '30m', '1h', '3h', '6h', '12h', '1d', '3d', '7d'];

  static styles = css`
        :host {
            display: flex;
            gap: 10px;
            align-items: center;
        }

        .time-control {
            display: flex;
            align-items: center;
            background: #424242;
            border: 1px solid #616161;
            border-radius: 4px;
            overflow: hidden;
        }

        button {
            background: transparent;
            border: none;
            color: #9e9e9e;
            padding: 6px 10px;
            cursor: pointer;
            font-size: 1em;
        }

        button:hover {
            background: #515151;
            color: #e0e0e0;
        }

        .value {
            padding: 6px 12px;
            color: #e0e0e0;
            font-size: 0.85em;
            min-width: 40px;
            text-align: center;
        }

        .end-value {
            cursor: pointer;
        }

        .end-value:hover {
            background: #515151;
        }

        .reset-btn:hover {
            color: #ef5350;
        }
    `;

  constructor() {
    super();
    this.duration = '1h';
    this.endTime = null;
    this.isLiveMode = true;
  }

  get durationIndex() {
    return TimeRangePicker.durations.indexOf(this.duration);
  }

  parseDuration(dur) {
    const match = dur.match(/^(\d+)([mhd])$/);
    if (!match) return 3600;
    const value = parseInt(match[1]);
    const unit = match[2];
    switch (unit) {
      case 'm': return value * 60;
      case 'h': return value * 3600;
      case 'd': return value * 86400;
      default: return 3600;
    }
  }

  adjustDuration(delta) {
    const durations = TimeRangePicker.durations;
    const newIndex = Math.max(0, Math.min(durations.length - 1, this.durationIndex + delta));
    this.duration = durations[newIndex];
    this.emitChange();
  }

  adjustEndTime(delta) {
    const durationSecs = this.parseDuration(this.duration);
    const step = durationSecs / 2;

    let newEndTime = this.endTime;
    if (newEndTime === null) {
      newEndTime = Math.floor(Date.now() / 1000);
    }
    newEndTime += delta * step;

    const now = Math.floor(Date.now() / 1000);
    if (newEndTime >= now) {
      this.resetToNow();
      return;
    }

    this.endTime = newEndTime;
    this.isLiveMode = false;
    this.emitChange();
  }

  resetToNow() {
    this.endTime = null;
    this.isLiveMode = true;
    this.emitChange();
  }

  emitChange() {
    this.dispatchEvent(new CustomEvent('change', {
      detail: {
        duration: this.duration,
        endTime: this.endTime,
        isLiveMode: this.isLiveMode
      }
    }));
  }

  formatEndTime() {
    if (this.endTime === null) {
      return 'now';
    }
    const date = new Date(this.endTime * 1000);
    return date.toLocaleString('zh-CN', {
      year: 'numeric',
      month: '2-digit',
      day: '2-digit',
      hour: '2-digit',
      minute: '2-digit',
      second: '2-digit'
    }).replace(/\//g, '-');
  }

  render() {
    return html`
            <div class="time-control">
                <button @click=${() => this.adjustDuration(-1)}>−</button>
                <span class="value">${this.duration}</span>
                <button @click=${() => this.adjustDuration(1)}>+</button>
            </div>
            <div class="time-control">
                <button @click=${() => this.adjustEndTime(-1)}>‹</button>
                <span class="value end-value" @click=${this.resetToNow}>
                    ${this.formatEndTime()}
                </span>
                <button @click=${() => this.adjustEndTime(1)}>›</button>
                <button class="reset-btn" @click=${this.resetToNow} title="Reset to now">×</button>
            </div>
        `;
  }
}

customElements.define('time-range-picker', TimeRangePicker);