/**
 * core-measure – Built-in V2-Plugin (Task A4.5).
 *
 * measure: 2 Klicks → Distanz+Winkel-Anzeige im Status. KEIN Element-Commit
 * (Legacy-Verhalten getreu — Messung ist Information, keine Zeichnung).
 * Distanzformatierung via bestehendem formatDistance(unit, scaleFactor).
 */
import type { PluginV2, ToolExtensionV2, FullToolContext } from '../../types';
import { formatDistance, formatArea } from '../../../utils/format';
import { polygonArea } from '../../../tools/modification/geometry';

type MeasurePhase = 0 | 1; // 0=wartet auf Start, 1=wartet auf Ende
let measureStart: import('../../../tools/modification/geometry').Pt | null = null;

export const measureTool: ToolExtensionV2 = {
  manifest: {
    id: 'measure',
    label: 'Messen',
    icon: '\u2194',
    ribbonTab: 'view',
    tags: ['basic'],
    description: 'Distanz und Winkel zwischen zwei Punkten messen',
  },
  optionsSchema: [],
  handlers: {
    down(e, ctx) {
      const c = ctx as FullToolContext;
      if (!measureStart) {
        measureStart = e.world;
        ctx.setStatus('Messung: Endpunkt klicken');
        return;
      }
      // Zweiter Klick → anzeigen (Legacy-Ausgabeformat)
      const rawDist = Math.hypot(e.world.x - measureStart.x, e.world.y - measureStart.y);
      const angle = (Math.atan2(e.world.y - measureStart.y, e.world.x - measureStart.x) * 180) / Math.PI;
      const unit = (c.options.unit as string | undefined) ?? 'mm';
      const scale = (c.options.scaleFactor as number | undefined) ?? 1;
      const distStr = formatDistance(rawDist, unit as never, scale);
      ctx.setStatus(`distance: ${distStr}  angle: ${angle.toFixed(1)}\u00b0`);
      measureStart = null;
    },
    cancel(ctx) {
      measureStart = null;
      ctx.setStatus('Messung abgebrochen');
    },
  },
};

/** V2-Plugin: Messwerkzeuge. */
// ─────────────────────────────────────────────────────────────
// Task H5: measure-area — Polygon-Fläche messen (Status-only).
// Klick: Punkt hinzufügen; ENTER: committet Fläche ab 3 Punkten;
// ESC/Rechtsklick: Abbruch. Kein Element-Commit (wie measure).
// ─────────────────────────────────────────────────────────────
let areaPts: Array<{ x: number; y: number }> = [];

export const measureAreaTool: ToolExtensionV2 = {
  manifest: {
    id: 'measure-area',
    label: 'Fläche messen',
    icon: '\u25a9',
    ribbonTab: 'canvas',
    tags: ['basic'],
    description: 'Polygon-Fläche messen: Punkte klicken, ENTER schließt ab',
  },
  optionsSchema: [
    { key: 'unit', label: 'Einheit', type: 'select', options: [
      { value: 'mm', label: 'mm' }, { value: 'cm', label: 'cm' }, { value: 'm', label: 'm' },
    ] },
    { key: 'scaleFactor', label: 'Maßstab (Welt→mm)', type: 'number' },
  ],
  handlers: {
    down(e, ctx) {
      areaPts.push({ x: e.world.x, y: e.world.y });
      if (areaPts.length === 1) {
        ctx.setStatus(`Flächenmessung gestartet (1 Punkt) — weitere Punkte klicken, ENTER schließt ab`);
      } else if (areaPts.length >= 3) {
        const unit = (ctx.options.unit as string | undefined) ?? 'mm';
        const scale = (ctx.options.scaleFactor as number | undefined) ?? 1;
        ctx.setStatus(`Fläche: ${formatArea(polygonArea(areaPts), unit as never, scale)} — weiter klicken oder ENTER`);
      } else {
        ctx.setStatus(`${areaPts.length} Punkte — mindestens 3 benötigt, weitere Punkte klicken`);
      }
    },
    move(e, ctx) {
      if (areaPts.length < 2) return;
      const probe = [...areaPts, { x: e.world.x, y: e.world.y }];
      if (probe.length < 3) return;
      const unit = (ctx.options.unit as string | undefined) ?? 'mm';
      const scale = (ctx.options.scaleFactor as number | undefined) ?? 1;
      ctx.setStatus(`Fläche: ${formatArea(polygonArea(probe), unit as never, scale)}`);
    },
    key(k, ctx) {
      if (k.key === 'Enter' || k.key === 'ENTER') {
        if (areaPts.length >= 3) {
          const unit = (ctx.options.unit as string | undefined) ?? 'mm';
          const scale = (ctx.options.scaleFactor as number | undefined) ?? 1;
          ctx.setStatus(`Flächenmessung: ${formatArea(polygonArea(areaPts), unit as never, scale)} (${areaPts.length} Punkte)`);
          areaPts = [];
        } else {
          ctx.setStatus(`Flächenmessung benötigt mindestens 3 Punkte (aktuell ${areaPts.length})`);
        }
        return true; // ENTER konsumiert
      }
      return false;
    },
    cancel(ctx) {
      areaPts = [];
      ctx.setStatus('Flächenmessung abgebrochen');
    },
  },
};

export const coreMeasurePlugin: PluginV2 = {
  manifest: {
    id: 'core-measure',
    name: 'Messen (Kern)',
    version: '1.0.0',
    author: 'web-cad team',
    description: 'Abstandswinkel-Messung ohne Element-Erzeugung.',
    category: 'tools',
    enabledByDefault: true,
  },
  tools: [measureTool, measureAreaTool],
};