/**
 * core-drawing – Built-in V2-Plugin (Task A3 Pilot).
 *
 * Werkzeuge: line (Migrations-Pilot aus dem Legacy-Switch).
 * Elemente werden über CADDocument committed → kollaborativ korrektes Undo.
 *
 * Sitzungszustand (Startpunkt der aktuellen Linie) lebt als Modul-Member,
 * NICHT in options: Options sind geteilter UI-Store-Zustand.
 */
import type { PluginV2, ToolExtensionV2, FullToolContext } from '../../types';
import type { CADElement } from '../../../types/cad.types';
import type { Pt } from '../../../tools/modification/geometry';

const uid = (prefix: string): string =>
  `${prefix}_${Date.now().toString(36)}_${Math.random().toString(36).slice(2, 9)}`;

/** Startpunkt der laufenden Linie (nur innerhalb einer down→up-Sitzung gesetzt). */
let lineStart: Pt | null = null;
/** Startpunkt des laufenden Rechtecks (A4.2). */
let rectStart: Pt | null = null;
/** Zentrum des laufenden Kreises (A4.3). */
let circleCenter: Pt | null = null;
/** Laufender Bogen: Phase 0=nichts, 1=Zentrum gesetzt, 2=Radius+Startwinkel gesetzt. */
let arcPhase = 0;
let arcCenter: Pt | null = null;
let arcStartPt: Pt | null = null;
/** Laufende Polyline/Polygon-Punkte; Commit per ENTER. */
let polyPoints: Pt[] = [];
/** Laufende RevCloud-Punkte (A4.5); Commit per ENTER. */
let cloudPoints: Pt[] = [];

function optsOf(ctx: FullToolContext): { stroke: string; layerId: string } {
  return {
    stroke: (ctx.options.strokeColor as string | undefined) ?? '#e0e0f0',
    layerId: (ctx.options.layerId as string | undefined) ?? 'layer-0',
  };
}

function buildLine(start: Pt, end: Pt, ctx: FullToolContext): CADElement {
  const stroke = (ctx.options.strokeColor as string | undefined) ?? '#e0e0f0';
  const layerId = (ctx.options.layerId as string | undefined) ?? 'layer-0';
  return {
    id: uid('line'),
    type: 'line',
    layerId,
    x: (start.x + end.x) / 2,
    y: (start.y + end.y) / 2,
    width: Math.abs(end.x - start.x),
    height: Math.abs(end.y - start.y),
    properties: { x1: start.x, y1: start.y, x2: end.x, y2: end.y, stroke, strokeWidth: 1 },
  } as unknown as CADElement;
}

function buildRect(cornerA: Pt, cornerB: Pt, ctx: FullToolContext): CADElement {
  const stroke = (ctx.options.strokeColor as string | undefined) ?? '#e0e0f0';
  const layerId = (ctx.options.layerId as string | undefined) ?? 'layer-0';
  const minX = Math.min(cornerA.x, cornerB.x);
  const minY = Math.min(cornerA.y, cornerB.y);
  const w = Math.abs(cornerB.x - cornerA.x);
  const h = Math.abs(cornerB.y - cornerA.y);
  return {
    id: uid('rect'),
    type: 'rect',
    layerId,
    x: minX + w / 2,          // BBox-Zentrum (Legacy-Konvention)
    y: minY + h / 2,
    width: w,
    height: h,
    properties: { stroke, strokeWidth: 1 },
  } as unknown as CADElement;
}

/**
 * line-Werkzeug: down setzt Startpunkt, move zeigt Live-Vorschau,
 * up committet via doc.transact (1 Linie = 1 Undo-Schritt).
 */
export const lineTool: ToolExtensionV2 = {
  manifest: {
    id: 'line',
    label: 'Linie',
    icon: '\u2571',
    ribbonTab: 'canvas',
    tags: ['basic'],
    description: 'Zeichnet eine Linie (Klick Start, Klick Ende)',
  },
  optionsSchema: [
    { key: 'strokeColor', label: 'Farbe', type: 'color' },
  ],
  handlers: {
    down(e, ctx) {
      lineStart = e.world;
      ctx.setStatus(`Linie ab (${lineStart.x.toFixed(0)}, ${lineStart.y.toFixed(0)}) – Ende wählen`);
    },
    move(e, ctx) {
      if (!lineStart) return;
      ctx.setPreview?.(buildLine(lineStart, e.world, ctx));
    },
    up(e, ctx) {
      const c = ctx as FullToolContext;
      if (!lineStart || !c.doc) {
        lineStart = null;
        return;
      }
      const el = buildLine(lineStart, e.world, c);
      c.doc.transact(() => {
        // addElement öffnet inneres transact — Yjs verschachtelt sie → EIN Undo-Schritt
        c.doc!.addElement(el);
      });
      lineStart = null;
      ctx.setPreview?.(null);
      ctx.setStatus(`Linie erstellt (${el.id})`);
    },
    cancel(ctx) {
      lineStart = null;
      ctx.setPreview?.(null);
      ctx.setStatus('Linie abgebrochen');
    },
  },
};

/**
 * rect-Werkzeug (A4.2): down setzt Ecke, move zeigt BBox-Vorschau,
 * up committet via doc.transact. Portiert aus Legacy case 'rect'
 * (BBox-Konvention: x/y = Zentrum, width/height absolut).
 */
export const rectTool: ToolExtensionV2 = {
  manifest: {
    id: 'rect',
    label: 'Rechteck',
    icon: '\u25ad',
    ribbonTab: 'canvas',
    tags: ['basic'],
    description: 'Zieht ein Rechteck auf (Klick Ecke, Klick Gegenecke)',
  },
  optionsSchema: [
    { key: 'strokeColor', label: 'Farbe', type: 'color' },
  ],
  handlers: {
    down(e, ctx) {
      rectStart = e.world;
      ctx.setStatus(`Rechteck ab (${rectStart.x.toFixed(0)}, ${rectStart.y.toFixed(0)}) – Gegenecke wählen`);
    },
    move(e, ctx) {
      if (!rectStart) return;
      ctx.setPreview?.(buildRect(rectStart, e.world, ctx));
    },
    up(e, ctx) {
      const c = ctx as FullToolContext;
      if (!rectStart || !c.doc) {
        rectStart = null;
        return;
      }
      const el = buildRect(rectStart, e.world, c);
      c.doc.transact(() => {
        c.doc!.addElement(el);
      });
      rectStart = null;
      ctx.setPreview?.(null);
      ctx.setStatus(`Rechteck erstellt (${el.id})`);
    },
    cancel(ctx) {
      rectStart = null;
      ctx.setPreview?.(null);
      ctx.setStatus('Rechteck abgebrochen');
    },
  },
};

/**
 * circle-Werkzeug (A4.3): Zentrum→Radius wie Legacy (Radius = Distanz).
 */
export const circleTool: ToolExtensionV2 = {
  manifest: {
    id: 'circle', label: 'Kreis', icon: '\u25cb', ribbonTab: 'canvas', tags: ['basic'],
    description: 'Kreis: Zentrum klicken, Radius ziehen',
  },
  optionsSchema: [{ key: 'strokeColor', label: 'Farbe', type: 'color' }],
  handlers: {
    down(e, ctx) { circleCenter = e.world; ctx.setStatus('Kreiszentrum gesetzt – Radius ziehen'); },
    move(e, ctx) {
      if (!circleCenter) return;
      const r = Math.hypot(e.world.x - circleCenter.x, e.world.y - circleCenter.y);
      ctx.setPreview?.(buildCircle(circleCenter, r, ctx));
    },
    up(e, ctx) {
      const c = ctx as FullToolContext;
      if (!circleCenter || !c.doc) { circleCenter = null; return; }
      const r = Math.hypot(e.world.x - circleCenter.x, e.world.y - circleCenter.y);
      const el = buildCircle(circleCenter, r, c);
      c.doc.transact(() => c.doc!.addElement(el));
      circleCenter = null;
      ctx.setPreview?.(null);
      ctx.setStatus(`Kreis erstellt (${el.id})`);
    },
    cancel(ctx) { circleCenter = null; ctx.setPreview?.(null); ctx.setStatus('Kreis abgebrochen'); },
  },
};

/**
 * arc-Werkzeug (A4.3): 3-Klick wie Legacy — Zentrum, Startpunkt (Radius+
 * Startwinkel), Endpunkt (Endwinkel). Winkel in Grad CCW.
 */
export const arcTool: ToolExtensionV2 = {
  manifest: {
    id: 'arc', label: 'Bogen', icon: '\u2322', ribbonTab: 'canvas', tags: ['basic'],
    description: 'Bogen: Zentrum, Startpunkt, Endpunkt',
  },
  optionsSchema: [{ key: 'strokeColor', label: 'Farbe', type: 'color' }],
  handlers: {
    down(e, ctx) {
      const c = ctx as FullToolContext;
      if (arcPhase === 0) {
        arcCenter = e.world;
        arcPhase = 1;
        ctx.setStatus('Bogenzentrum gesetzt \u2013 Startpunkt w\u00e4hlen');
      } else if (arcPhase === 1) {
        arcStartPt = e.world;
        arcPhase = 2;
        ctx.setStatus('Bogen: Endpunkt w\u00e4hlen');
      } else if (arcPhase === 2 && arcCenter && arcStartPt) {
        // Dritter Klick committet (klick-progressiv wie Legacy — up feuert im
        // echten Browser immer direkt nach down, darf deshalb NICHT committen)
        if (!c.doc) { arcPhase = 0; arcCenter = null; arcStartPt = null; return; }
        const el = buildArc(arcCenter, arcStartPt, e.world, c);
        c.doc.transact(() => c.doc!.addElement(el));
        ctx.setPreview?.(null);
        ctx.setStatus(`Bogen erstellt (${el.id})`);
        arcPhase = 0;
        arcCenter = null;
        arcStartPt = null;
      }
    },
    move(e, ctx) {
      if (arcPhase === 1 && arcCenter) {
        const r = Math.hypot(e.world.x - arcCenter.x, e.world.y - arcCenter.y);
        // Vollkreis-Guide in Phasen-Preview (Legacy-Konvention)
        ctx.setPreview?.(buildArcFullGuide(arcCenter, r, ctx));
      } else if (arcPhase === 2 && arcCenter && arcStartPt) {
        ctx.setPreview?.(buildArc(arcCenter, arcStartPt, e.world, ctx));
      }
    },
    cancel(ctx) {
      arcPhase = 0; arcCenter = null; arcStartPt = null;
      ctx.setPreview?.(null); ctx.setStatus('Bogen abgebrochen');
    },
  },
};

/**
 * polyline-Werkzeug (A4.3): Mehrklick fügt Punkte; ENTER committet ab 2 Punkten.
 */
export const polylineTool: ToolExtensionV2 = makePolyTool('polyline', 'Polylinie', 2, '\u2500');

/**
 * polygon-Werkzeug (A4.3): wie Polylinie, aber geschlossen; ENTER ab 3 Punkten.
 */
export const polygonTool: ToolExtensionV2 = makePolyTool('polygon', 'Polygon', 3, '\u2b21');

function makePolyTool(type: 'polyline' | 'polygon', label: string, minPoints: number, icon: string): ToolExtensionV2 {
  return {
    manifest: { id: type, label, icon, ribbonTab: 'canvas', tags: ['basic'], description: `${label}: Punkte klicken, ENTER beendet` },
    optionsSchema: [{ key: 'strokeColor', label: 'Farbe', type: 'color' }],
    handlers: {
      down(e, ctx) {
        polyPoints.push(e.world);
        if (!isPolyType(type)) return;
        ctx.setStatus(`${label}: ${polyPoints.length} Punkte – ENTER beendet`);
      },
      move(e, ctx) {
        if (polyPoints.length === 0) return;
        const pts = [...polyPoints, e.world];
        ctx.setPreview?.(buildPoly(type, pts, ctx));
      },
      up() { /* commit nur via ENTER */ },
      key(e, ctx) {
        if (e.key !== 'Enter') return false;
        if (polyPoints.length < minPoints) {
          ctx.setStatus(`${label}: mindestens ${minPoints} Punkte nötig`);
          return true; // konsumiert
        }
        const el = buildPoly(type, polyPoints, ctx as FullToolContext);
        const doc = (ctx as FullToolContext).doc;
        if (!doc) { resetPoly(); return true; }
        doc.transact(() => doc.addElement(el));
        resetPoly();
        ctx.setPreview?.(null);
        ctx.setStatus(`${label} erstellt (${el.id})`);
        return true;
      },
      cancel(ctx) {
        resetPoly();
        ctx.setPreview?.(null);
        ctx.setStatus(`${label} abgebrochen`);
      },
    },
  };
}

function isPolyType(t: string): boolean {
  return t === 'polyline' || t === 'polygon';
}

function resetPoly(): void {
  polyPoints = [];
}

// ─── Build-Helfer A4.3 ───────────────────────────────────────

function buildCircle(center: Pt, radius: number, ctx: FullToolContext): CADElement {
  const o = optsOf(ctx);
  return {
    id: uid('circle'), type: 'circle', layerId: o.layerId,
    x: center.x, y: center.y, width: radius * 2, height: radius * 2,
    properties: { radius, stroke: o.stroke, strokeWidth: 1 },
  } as unknown as CADElement;
}

function anglesOf(center: Pt, start: Pt, end: Pt): { radius: number; startAngle: number; endAngle: number } {
  const radius = Math.hypot(start.x - center.x, start.y - center.y);
  const startAngle = (Math.atan2(start.y - center.y, start.x - center.x) * 180) / Math.PI;
  const endAngle = (Math.atan2(end.y - center.y, end.x - center.x) * 180) / Math.PI;
  return { radius, startAngle, endAngle };
}

function buildArc(center: Pt, startPt: Pt, endPt: Pt, ctx: FullToolContext): CADElement {
  const o = optsOf(ctx);
  const a = anglesOf(center, startPt, endPt);
  return {
    id: uid('arc'), type: 'arc', layerId: o.layerId,
    x: center.x, y: center.y, width: a.radius * 2, height: a.radius * 2,
    properties: { radius: a.radius, startAngle: a.startAngle, endAngle: a.endAngle, stroke: o.stroke, strokeWidth: 1 },
  } as unknown as CADElement;
}

function buildArcFullGuide(center: Pt, radius: number, ctx: FullToolContext): CADElement {
  // Vollkreis-Vorschau als Radien-Leitfaden (Legacy-Verhalten Phase 1)
  const o = optsOf(ctx);
  return {
    id: uid('arc'), type: 'circle', layerId: o.layerId,
    x: center.x, y: center.y, width: radius * 2, height: radius * 2,
    properties: { radius, stroke: o.stroke, strokeWidth: 1, guideOnly: true },
  } as unknown as CADElement;
}

function buildPoly(type: 'polyline' | 'polygon', pts: Pt[], ctx: FullToolContext): CADElement {
  const o = optsOf(ctx);
  const xs = pts.map((p) => p.x);
  const ys = pts.map((p) => p.y);
  return {
    id: uid(type), type, layerId: o.layerId,
    x: (Math.min(...xs) + Math.max(...xs)) / 2,
    y: (Math.min(...ys) + Math.max(...ys)) / 2,
    width: Math.max(...xs) - Math.min(...xs),
    height: Math.max(...ys) - Math.min(...ys),
    properties: { points: pts.map((p) => ({ x: p.x, y: p.y })), stroke: o.stroke, strokeWidth: 1 },
  } as unknown as CADElement;
}

/**
 * revcloud-Werkzeug (A4.5): Mehrklick-Revisionswolke wie Poly-Muster;
 * ENTER committet ab 3 Punkten. Legacy-Konvention: arcHeight 8.
 */
export const revcloudTool: ToolExtensionV2 = {
  manifest: {
    id: 'revcloud', label: 'RevCloud', icon: '\u2611', ribbonTab: 'format', tags: ['pro'],
    description: 'Revisionswolke: Punkte klicken, ENTER beendet',
  },
  optionsSchema: [{ key: 'strokeColor', label: 'Farbe', type: 'color' }],
  handlers: {
    down(e, ctx) {
      cloudPoints.push(e.world);
      ctx.setStatus(`RevCloud: ${cloudPoints.length} Punkte \u2013 ENTER beendet`);
    },
    move(e, ctx) {
      if (cloudPoints.length === 0) return;
      ctx.setPreview?.(buildRevCloud([...cloudPoints, e.world], ctx));
    },
    up() { /* commit via ENTER */ },
    key(e, ctx) {
      if (e.key !== 'Enter') return false;
      if (cloudPoints.length < 3) {
        ctx.setStatus('RevCloud: mindestens 3 Punkte n\u00f6tig');
        return true;
      }
      const c = ctx as FullToolContext;
      if (!c.doc) { cloudPoints = []; return true; }
      const el = buildRevCloud(cloudPoints, c);
      c.doc.transact(() => c.doc!.addElement(el));
      cloudPoints = [];
      ctx.setPreview?.(null);
      ctx.setStatus(`RevCloud erstellt (${el.id})`);
      return true;
    },
    cancel(ctx) {
      cloudPoints = [];
      ctx.setPreview?.(null);
      ctx.setStatus('RevCloud abgebrochen');
    },
  },
};

function buildRevCloud(pts: Pt[], ctx: FullToolContext): CADElement {
  const o = optsOf(ctx);
  const xs = pts.map((p) => p.x);
  const ys = pts.map((p) => p.y);
  return {
    id: uid('revcloud'), type: 'revcloud', layerId: o.layerId,
    x: (Math.min(...xs) + Math.max(...xs)) / 2,
    y: (Math.min(...ys) + Math.max(...ys)) / 2,
    width: Math.max(...xs) - Math.min(...xs),
    height: Math.max(...ys) - Math.min(...ys),
    properties: { points: pts.map((p) => ({ x: p.x, y: p.y })), arcHeight: 8, fill: 'none', stroke: '#e0e0e0', strokeWidth: 1.5 },
  } as unknown as CADElement;
}

/** V2-Plugin: Kern-Zeichenwerkzeuge (A4.x schrittweise migriert). */
// ─────────────────────────────────────────────────────────────
// Task D1: Ellipse (3-Klick: Zentrum→RadiusX→RadiusY) +
// Ellipsenbogen via startAngle/endAngle-Options.
// ─────────────────────────────────────────────────────────────

/** Ellipsen-Sitzung: Phase 0=nichts, 1=Zentrum, 2=RadiusX fixiert. */
let ellipsePhase = 0;
let ellipseCenter: Pt | null = null;
let ellipseRadiusX = 0;
/** Rotation aus der Klick2-Zugrichtung (Grad, 0°=+x, CW-positiv). */
let ellipseRotationDeg = 0;

/**
 * Ellipse als Polyline-Approximation (F5-Parser-Konvention):
 * Voll-Ellipse → 64 Punkte geschlossen (polygon), Bogen → proportional
 * offene Polyline. rotation aus der Klick2-Zugrichtung (Grad, 0°=+x).
 */
function buildEllipse(
  cx: number,
  cy: number,
  rx: number,
  ry: number,
  rotationDeg: number,
  ctx: FullToolContext,
  startAngle = 0,
  endAngle = 360,
): CADElement {
  const stroke = (ctx.options.strokeColor as string | undefined) ?? '#e0e0f0';
  const layerId = (ctx.options.layerId as string | undefined) ?? 'layer-0';
  const phi = (rotationDeg * Math.PI) / 180;
  const cosP = Math.cos(phi), sinP = Math.sin(phi);
  const FULL = 360;
  const span = Math.min(endAngle, FULL) - Math.min(startAngle, FULL);
  const isFull = span >= FULL - 0.001 || span <= 0.001;
  const n = Math.max(2, Math.round(64 * (Math.max(span, 1) / FULL)));
  const pts: Pt[] = [];
  for (let i = 0; i < n; i++) {
    const t = ((startAngle + (span * i) / (isFull ? n : (n - 1))) * Math.PI) / 180;
    const x = rx * Math.cos(t);
    const y = ry * Math.sin(t);
    pts.push({
      x: cx + x * cosP - y * sinP,
      y: cy + x * sinP + y * cosP,
    });
  }
  const xs = pts.map((p) => p.x), ys = pts.map((p) => p.y);
  const minX = Math.min(...xs), minY = Math.min(...ys);
  const type = isFull ? 'polygon' : 'polyline';
  return {
    id: uid('ellipse'),
    type,
    layerId,
    x: minX + (Math.max(...xs) - minX) / 2,
    y: minY + (Math.max(...ys) - minY) / 2,
    width: Math.max(...xs) - minX,
    height: Math.max(...ys) - minY,
    properties: {
      points: pts,
      stroke,
      strokeWidth: 1,
      cx, cy, rx, ry,
      rotation: rotationDeg,
      ...(isFull ? {} : { startAngle, endAngle }),
    },
  } as unknown as CADElement;
}

export const ellipseTool: ToolExtensionV2 = {
  manifest: {
    id: 'ellipse',
    label: 'Ellipse',
    icon: '\u2b2d',
    ribbonTab: 'canvas',
    tags: ['basic'],
    description: 'Ellipse zeichnen: Zentrum klicken, RadiusX, RadiusY (Bogen via Optionen)',
  },
  optionsSchema: [
    { key: 'strokeColor', label: 'Farbe', type: 'color' },
    { key: 'startAngle', label: 'Bogen-Start (°)', type: 'number', min: 0, max: 360 },
    { key: 'endAngle', label: 'Bogen-Ende (°)', type: 'number', min: 0, max: 360 },
  ],
  handlers: {
    down(e, ctx) {
      const c = ctx as FullToolContext;
      if (ellipsePhase === 0) {
        ellipseCenter = e.world;
        ellipsePhase = 1;
        ctx.setStatus('Ellipse: Zentrum gesetzt – RadiusX klicken (Richtung = Rotation)');
      } else if (ellipsePhase === 1) {
        if (!ellipseCenter) { ellipsePhase = 0; return; }
        const dx = e.world.x - ellipseCenter.x;
        const dy = e.world.y - ellipseCenter.y;
        ellipseRadiusX = Math.hypot(dx, dy);
        ellipseRotationDeg = ((Math.atan2(dy, dx) * 180) / Math.PI + 360) % 360;
        ellipsePhase = 2;
        ctx.setStatus('Ellipse: RadiusX gesetzt – RadiusY klicken');
      } else {
        // Phase 2: Commit
        if (!ellipseCenter || !c.doc) { ellipsePhase = 0; ellipseCenter = null; return; }
        const dx = e.world.x - ellipseCenter.x;
        const dy = e.world.y - ellipseCenter.y;
        const ry = Math.hypot(dx, dy);
        // Rotation: Winkel des Klick2-Vektors gegenüber der +x-Achse
        const startAngle = (ctx.options.startAngle as number | undefined) ?? 0;
        const endAngle = (ctx.options.endAngle as number | undefined) ?? 360;
        const el = buildEllipse(
          ellipseCenter.x, ellipseCenter.y,
          ellipseRadiusX, ry,
          ellipseRotationDeg,
          c, startAngle, endAngle,
        );
        c.doc.transact(() => c.doc!.addElement(el));
        ellipsePhase = 0;
        ellipseCenter = null;
        ctx.setPreview?.(null);
        ctx.setStatus(`Ellipse erstellt (${el.id})`);
      }
    },
    move(e, ctx) {
      const c = ctx as FullToolContext;
      if (ellipsePhase === 1 && ellipseCenter) {
        // RadiusX-Linie als Preview
        const r = Math.hypot(e.world.x - ellipseCenter.x, e.world.y - ellipseCenter.y);
        const rotDeg = ((Math.atan2(e.world.y - ellipseCenter.y, e.world.x - ellipseCenter.x) * 180) / Math.PI + 360) % 360;
        const startAngle = (ctx.options.startAngle as number | undefined) ?? 0;
        const endAngle = (ctx.options.endAngle as number | undefined) ?? 360;
        ctx.setPreview?.(buildEllipse(ellipseCenter.x, ellipseCenter.y, r, r, rotDeg, c, startAngle, endAngle));
      } else if (ellipsePhase === 2 && ellipseCenter) {
        const ry = Math.hypot(e.world.x - ellipseCenter.x, e.world.y - ellipseCenter.y);
        const rotDeg = ellipseRotationDeg;
        const startAngle = (ctx.options.startAngle as number | undefined) ?? 0;
        const endAngle = (ctx.options.endAngle as number | undefined) ?? 360;
        ctx.setPreview?.(buildEllipse(ellipseCenter.x, ellipseCenter.y, ellipseRadiusX, ry, rotDeg, c, startAngle, endAngle));
      }
    },
    cancel(ctx) {
      ellipsePhase = 0;
      ellipseCenter = null;
      ctx.setPreview?.(null);
      ctx.setStatus('Ellipse abgebrochen');
    },
  },
};

// ─────────────────────────────────────────────────────────────
// Task D2: Spline (CV-basiert) — Kontrollpunkt-Klick-Sequenz,
// ENTER committet ab 3 CVs. Catmull-Rom-Interpolation (Kurve läuft
// DURCH alle CVs, schwingt an Ecken = echte Glättung).
// ─────────────────────────────────────────────────────────────

let splinePoints: Pt[] = [];

/**
 * Catmull-Rom-Spline-Interpolation: Für n CVs werden n-1 Segmente
 * mit je SEG Samples erzeugt. Tangenten aus Nachbarn (Endpunkte
 * geklemmt). Ergibt eine glatte Kurve durch alle CVs.
 */
function catmullRom(cvs: Pt[], seg = 16): Pt[] {
  if (cvs.length < 2) return [...cvs];
  const out: Pt[] = [];
  const n = cvs.length;
  for (let i = 0; i < n - 1; i++) {
    const p0 = cvs[Math.max(0, i - 1)];
    const p1 = cvs[i];
    const p2 = cvs[i + 1];
    const p3 = cvs[Math.min(n - 1, i + 2)];
    for (let s = (i === 0 ? 0 : 1); s <= seg; s++) {
      const t = s / seg;
      const t2 = t * t;
      const t3 = t2 * t;
      const x = 0.5 * ((2 * p1.x) + (-p0.x + p2.x) * t + (2 * p0.x - 5 * p1.x + 4 * p2.x - p3.x) * t2 + (-p0.x + 3 * p1.x - 3 * p2.x + p3.x) * t3);
      const y = 0.5 * ((2 * p1.y) + (-p0.y + p2.y) * t + (2 * p0.y - 5 * p1.y + 4 * p2.y - p3.y) * t2 + (-p0.y + 3 * p1.y - 3 * p2.y + p3.y) * t3);
      out.push({ x, y });
    }
  }
  return out;
}

function buildSpline(cvs: Pt[], ctx: FullToolContext): CADElement {
  const stroke = (ctx.options.strokeColor as string | undefined) ?? '#e0e0f0';
  const layerId = (ctx.options.layerId as string | undefined) ?? 'layer-0';
  const pts = catmullRom(cvs);
  const xs = pts.map((p) => p.x), ys = pts.map((p) => p.y);
  const minX = Math.min(...xs), minY = Math.min(...ys);
  const maxX = Math.max(...xs), maxY = Math.max(...ys);
  return {
    id: uid('spline'),
    type: 'polyline',
    layerId,
    x: minX + (maxX - minX) / 2,
    y: minY + (maxY - minY) / 2,
    width: maxX - minX,
    height: maxY - minY,
    properties: {
      points: pts,
      controlPoints: [...cvs],
      stroke,
      strokeWidth: 1,
    },
  } as unknown as CADElement;
}

export const splineTool: ToolExtensionV2 = {
  manifest: {
    id: 'spline',
    label: 'Spline',
    icon: '\u2248',
    ribbonTab: 'canvas',
    tags: ['basic'],
    description: 'Spline zeichnen: Kontrollpunkte klicken, ENTER beendet',
  },
  optionsSchema: [{ key: 'strokeColor', label: 'Farbe', type: 'color' }],
  handlers: {
    down(e, ctx) {
      splinePoints.push(e.world);
      ctx.setStatus(`Spline: ${splinePoints.length} Kontrollpunkte – ENTER beendet`);
    },
    move(e, ctx) {
      const c = ctx as FullToolContext;
      if (splinePoints.length === 0) return;
      const pts = [...splinePoints, e.world];
      ctx.setPreview?.(buildSpline(pts, c));
    },
    up() { /* commit nur via ENTER */ },
    key(e, ctx) {
      if (e.key !== 'Enter' && e.key !== 'ENTER') return false;
      const c = ctx as FullToolContext;
      if (splinePoints.length < 3) {
        ctx.setStatus(`Spline benötigt mindestens 3 Kontrollpunkte (aktuell ${splinePoints.length})`);
        return true;
      }
      if (!c.doc) return false;
      const el = buildSpline(splinePoints, c);
      c.doc.transact(() => c.doc!.addElement(el));
      const count = splinePoints.length;
      splinePoints = [];
      ctx.setPreview?.(null);
      ctx.setStatus(`Spline erstellt (${count} CVs, ${el.id})`);
      return true;
    },
    cancel(ctx) {
      splinePoints = [];
      ctx.setPreview?.(null);
      ctx.setStatus('Spline abgebrochen');
    },
  },
};

export const coreDrawingPlugin: PluginV2 = {
  manifest: {
    id: 'core-drawing',
    name: 'Zeichnen (Kern)',
    version: '1.4.0',
    author: 'web-cad team',
    description: 'Zeichenwerkzeuge V2: Linie, Rechteck, Kreis, Bogen, Polylinie, Polygon, RevCloud.',
    category: 'tools',
    enabledByDefault: true,
  },
  tools: [lineTool, rectTool, circleTool, arcTool, polylineTool, polygonTool, revcloudTool, ellipseTool, splineTool],
};