/**
 * core-modify – Built-in V2-Plugin.
 *
 * Werkzeuge:
 * - select (A3): Klick-Auswahl mit Shift/Ctrl
 * - hatch (A4.5): Schraffur via doc.updateElement
 * - move/copy (A4.6): selektionsbasiert, Basis→Ziel
 * - rotate/scale/mirror (A4.7): gleiche Selektions-Konvention,
 *   Legacy-Transform-Mathematik aus handleModifyMove übernommen
 *
 * Alle Commits laufen über CADDocument → kollaborativ korrektes Undo.
 */
import type { PluginV2, ToolExtensionV2 } from '../../types';
import type { FullToolContext } from '../../types';
import type { CADElement } from '../../../types/cad.types';
import {
  moveElement,
  rotateElement,
  scaleElement,
  mirrorElement,
  angleBetween,
  distance,
  offsetElement,
} from '../../../tools/modification/geometry';
import type { Pt } from '../../../tools/modification/geometry';

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

// ─────────────────────────────────────────────────────────────
// select (Task A3 – Pilot)
// ─────────────────────────────────────────────────────────────
export const selectTool: ToolExtensionV2 = {
  manifest: {
    id: 'select',
    label: 'Auswahl',
    icon: '\u2196',
    ribbonTab: 'canvas',
    tags: ['basic'],
    description: 'Elemente anklicken zum Auswählen',
  },
  optionsSchema: [],
  handlers: {
    down(e, ctx) {
      const bridge = (ctx as FullToolContext).selection;
      if (!bridge) return;
      const additive = e.shift;
      const subtractive = e.ctrl;
      const hit = bridge.hitTest(e.world.x, e.world.y, 5);
      if (!hit) {
        if (!additive && !subtractive) bridge.setIds([]);
        return;
      }
      let ids = new Set(bridge.getIds());
      if (subtractive) {
        ids.delete(hit.id);
      } else {
        ids.add(hit.id);
        if (!additive) ids = new Set([hit.id]);
      }
      bridge.setIds(Array.from(ids));
      ctx.setStatus(`Selektion: ${ids.size} Element(e)`);
    },
  },
};

// ─────────────────────────────────────────────────────────────
// hatch (Task A4.5)
// ─────────────────────────────────────────────────────────────
export const hatchTool: ToolExtensionV2 = {
  manifest: {
    id: 'hatch', label: 'Schraffur', icon: '\u2593', ribbonTab: 'format', tags: ['pro'],
    description: 'Geschlossenes Element anklicken zum Schraffieren',
  },
  optionsSchema: [
    { key: 'hatchPattern', label: 'Muster', type: 'select', options: [
      { value: 'lines', label: 'Linien' },
      { value: 'cross', label: 'Kreuz' },
    ] },
    { key: 'hatchSpacing', label: 'Abstand', type: 'number', min: 2, max: 40 },
  ],
  handlers: {
    down(e, ctx) {
      const c = ctx as FullToolContext;
      const bridge = c.selection;
      if (!bridge || !c.doc) return;
      const hit = bridge.hitTest(e.world.x, e.world.y, 5);
      if (!hit || !['rect', 'circle', 'polygon'].includes(hit.type)) {
        ctx.setStatus('Schraffur: nur rect/circle/polygon');
        return;
      }
      const pattern = (c.options.hatchPattern as string | undefined) ?? 'lines';
      const spacing = (c.options.hatchSpacing as number | undefined) ?? 8;
      c.doc.updateElement(hit.id, {
        properties: { hatch: true, hatchPattern: pattern, hatchSpacing: spacing },
      });
      ctx.setStatus(`Schraffur auf ${hit.id} (${pattern})`);
    },
  },
};

// ─────────────────────────────────────────────────────────────
// Move/Copy (Task A4.6)
// ─────────────────────────────────────────────────────────────
let modBasePoint: Pt | null = null;

function makeMoveCopyTool(mode: 'move' | 'copy'): ToolExtensionV2 {
  const label = mode === 'move' ? 'Verschieben' : 'Kopieren';
  return {
    manifest: {
      id: mode,
      label,
      icon: mode === 'move' ? '\u27a4' : '\u29c9',
      ribbonTab: 'canvas',
      tags: ['basic'],
      description: `${label}: Auswahl treffen, dann Basis\u2192Ziel klicken`,
    },
    optionsSchema: [],
    handlers: {
      down(e, ctx) {
        const c = ctx as FullToolContext;
        if (!c.doc || !c.selection) return;
        if (!modBasePoint) {
          const ids = c.selection.getIds();
          if (ids.length === 0) {
            const hit = c.selection.hitTest(e.world.x, e.world.y, 5);
            if (!hit) {
              ctx.setStatus(`${label}: zuerst Element(e) auswählen`);
              return;
            }
            c.selection.setIds([hit.id]);
          }
          modBasePoint = e.world;
          ctx.setStatus(`${label}: Zielklick zum ${mode === 'move' ? 'Verschieben' : 'Kopieren'} (${c.selection.getIds().length} Elemente)`);
          return;
        }
        const dx = e.world.x - modBasePoint.x;
        const dy = e.world.y - modBasePoint.y;
        const ids = c.selection.getIds();
        c.doc.transact(() => {
          for (const id of ids) {
            const el = c.doc!.getElement(id);
            if (!el) continue;
            if (mode === 'move') {
              c.doc!.updateElement(id, { x: el.x + dx, y: el.y + dy });
            } else {
              c.doc!.addElement({
                ...el,
                id: uid('cp'),
                x: el.x + dx,
                y: el.y + dy,
              });
            }
          }
        });
        ctx.setStatus(`${label}: ${ids.length} Element(e), \u0394(${dx.toFixed(0)}, ${dy.toFixed(0)})`);
        modBasePoint = null;
      },
      cancel(ctx) {
        modBasePoint = null;
        ctx.setStatus(`${label} abgebrochen`);
      },
    },
  };
}
export const moveTool: ToolExtensionV2 = makeMoveCopyTool('move');
export const copyTool: ToolExtensionV2 = makeMoveCopyTool('copy');

// ─────────────────────────────────────────────────────────────
// Rotate / Scale / Mirror (Task A4.7)
// Konventionen exakt aus Legacy handleModifyMove:
// - rotate: Pivot = Zentrum des ERSTEN selektierten Elements,
//   Δwinkel = angleBetween(pivot,zweitKlick) − angleBetween(pivot,basis)
// - scale: Faktor = dist(pivot,zweitKlick) / dist(pivot,basis)
// - mirror: Spiegelachse = Linie basis→zweitKlick
// Klick-progressiv: Commit beim ZWEITEN down (Arc-Lektion).
// ─────────────────────────────────────────────────────────────
let transformBase: Pt | null = null;

function makeTransformTool(mode: 'rotate' | 'scale' | 'mirror'): ToolExtensionV2 {
  const labels = { rotate: 'Rotieren', scale: 'Skalieren', mirror: 'Spiegeln' } as const;
  const iconMap = { rotate: '\u21bb', scale: '\u2922', mirror: '\u21c6' } as const;
  return {
    manifest: {
      id: mode,
      label: labels[mode],
      icon: iconMap[mode],
      ribbonTab: 'canvas',
      tags: ['pro'],
      description: `${labels[mode]}: Auswahl treffen, dann Basis\u2192Referenz klicken`,
    },
    optionsSchema: [],
    handlers: {
      down(e, ctx) {
        const c = ctx as FullToolContext;
        if (!c.doc || !c.selection) return;
        if (!transformBase) {
          if (c.selection.getIds().length === 0) {
            const hit = c.selection.hitTest(e.world.x, e.world.y, 5);
            if (!hit) {
              ctx.setStatus(`${labels[mode]}: zuerst Element(e) auswählen`);
              return;
            }
            c.selection.setIds([hit.id]);
          }
          transformBase = e.world;
          ctx.setStatus(`${labels[mode]}: Referenzklick zum Anwenden (${c.selection.getIds().length} Elemente)`);
          return;
        }
        // Zweiter Klick → Commit auf ALLE selektierten Elemente, EINE Transaktion
        const base = transformBase;
        const ids = c.selection.getIds();
        const first = c.doc.getElement(ids[0]);
        if (!first) { transformBase = null; return; }
        const pivot = { x: first.x, y: first.y };
        c.doc.transact(() => {
          for (const id of ids) {
            const el = c.doc!.getElement(id);
            if (!el) continue;
            let next: CADElement;
            if (mode === 'rotate') {
              const delta = angleBetween(pivot, e.world) - angleBetween(pivot, base);
              next = rotateElement(el, pivot.x, pivot.y, delta);
            } else if (mode === 'scale') {
              const sd = distance(pivot, base);
              const cd = distance(pivot, e.world);
              const factor = sd > 0 ? cd / sd : 1;
              next = scaleElement(el, pivot.x, pivot.y, factor, factor);
            } else {
              next = mirrorElement(el, base.x, base.y, e.world.x, e.world.y);
            }
            c.doc!.updateElement(id, {
              x: next.x, y: next.y,
              width: next.width, height: next.height,
              properties: next.properties,
            });
          }
        });
        ctx.setStatus(`${labels[mode]}: ${ids.length} Element(e)`);
        transformBase = null;
      },
      move(e, ctx) {
        // Live-Vorschau am ersten selektierten Element (Legacy previewElement)
        const c = ctx as FullToolContext;
        if (!transformBase || !c.selection || !c.doc) return;
        const ids = c.selection.getIds();
        if (ids.length === 0) return;
        const first = c.doc.getElement(ids[0]);
        if (!first) return;
        const pivot = { x: first.x, y: first.y };
        let next: CADElement;
        if (mode === 'rotate') {
          const delta = angleBetween(pivot, e.world) - angleBetween(pivot, transformBase);
          next = rotateElement(first, pivot.x, pivot.y, delta);
        } else if (mode === 'scale') {
          const sd = distance(pivot, transformBase);
          const cd = distance(pivot, e.world);
          const f = sd > 0 ? cd / sd : 1;
          next = scaleElement(first, pivot.x, pivot.y, f, f);
        } else {
          next = mirrorElement(first, transformBase.x, transformBase.y, e.world.x, e.world.y);
        }
        ctx.setPreview?.(next);
      },
      cancel(ctx) {
        transformBase = null;
        ctx.setPreview?.(null);
        ctx.setStatus(`${labels[mode]} abgebrochen`);
      },
    },
  };
}
export const rotateTool: ToolExtensionV2 = makeTransformTool('rotate');
export const scaleTool: ToolExtensionV2 = makeTransformTool('scale');
export const mirrorTool: ToolExtensionV2 = makeTransformTool('mirror');

// ─────────────────────────────────────────────────────────────
// Delete (Task A4.8) — Portierung aus Legacy handleDeleteDown:
// Einzelnklick auf Element löscht es sofort (kein up/Bestätigung).
// Jetzt via doc.deleteElements → undo-fähig.
// ─────────────────────────────────────────────────────────────
export const deleteTool: ToolExtensionV2 = {
  manifest: {
    id: 'delete', label: 'Löschen', icon: '\u2715', ribbonTab: 'canvas', tags: ['basic'],
    description: 'Element anklicken zum Löschen',
  },
  optionsSchema: [],
  handlers: {
    down(e, ctx) {
      const c = ctx as FullToolContext;
      if (!c.doc || !c.selection) return;
      const ids = c.selection.getIds();
      if (ids.length > 0) {
        // Selektion vorhanden → alles selektierte löschen
        c.doc.deleteElements(ids);
        c.selection.setIds([]);
        ctx.setStatus(`${ids.length} Element(e) gelöscht`);
        return;
      }
      // Sonst: direkter Klick-Treffer
      const hit = c.selection.hitTest(e.world.x, e.world.y, 5);
      if (!hit) return;
      c.doc.deleteElements([hit.id]);
      ctx.setStatus(`Gelöscht: ${hit.id}`);
    },
  },
};

// ─────────────────────────────────────────────────────────────
// Offset (Task A4.8) — nutzt die BUG-3-reparierte offsetElement-
// Signatur mit Seitenparameter; Legacy-Ablauf:
// Klick1 = Element wählen, Klick2 = Richtung+Distanz → NEUES Element.
// ─────────────────────────────────────────────────────────────
let offsetSource: CADElement | null = null;
let offsetBase: Pt | null = null;

export const offsetTool: ToolExtensionV2 = {
  manifest: {
    id: 'offset', label: 'Versatz', icon: '\u2937', ribbonTab: 'canvas', tags: ['pro'],
    description: 'Element anklicken, dann seitlichen Versatz klicken',
  },
  optionsSchema: [],
  handlers: {
    down(e, ctx) {
      const c = ctx as FullToolContext;
      if (!c.doc || !c.selection) return;
      if (!offsetSource) {
        const hit = c.selection.hitTest(e.world.x, e.world.y, 5);
        if (!hit) return;
        offsetSource = hit;
        offsetBase = e.world;
        ctx.setStatus(`Offset: Element ${hit.id} gewählt – Versatz klicken`);
        return;
      }
      // Zweiter Klick: Distanz + Seite (Kreuzprodukt für Linien, Radius sonst)
      const src = c.doc.getElement(offsetSource.id);
      if (!src) { offsetSource = null; offsetBase = null; return; }
      const dist = Math.hypot(e.world.x - offsetBase!.x, e.world.y - offsetBase!.y);
      let side: 1 | -1 = 1;
      if (src.type === 'line' && src.properties.x1 !== undefined && src.properties.y1 !== undefined) {
        const p1x = src.properties.x1 as number;
        const p1y = src.properties.y1 as number;
        const p2x = src.properties.x2 as number;
        const p2y = src.properties.y2 as number;
        side = (p2x - p1x) * (e.world.y - p1y) - (p2y - p1y) * (e.world.x - p1x) >= 0 ? 1 : -1;
      } else if ((src.type === 'circle' || src.type === 'arc') && src.properties.radius !== undefined) {
        side = Math.hypot(e.world.x - src.x, e.world.y - src.y) >= (src.properties.radius as number) ? 1 : -1;
      }
      const next = offsetElement(src, dist, side);
      let newEl: CADElement | null = null;
      c.doc.transact(() => {
        newEl = { ...next, id: uid('off') };
        c.doc!.addElement(newEl!);
      });
      ctx.setStatus(`Offset erstellt (${(newEl as unknown as CADElement).id})`);
      offsetSource = null;
      offsetBase = null;
    },
    cancel(ctx) {
      offsetSource = null;
      offsetBase = null;
      ctx.setStatus('Offset abgebrochen');
    },
  },
};

/** V2-Plugin: Kern-Bearbeitungswerkzeuge. */
export const coreModifyPlugin: PluginV2 = {
  manifest: {
    id: 'core-modify',
    name: 'Bearbeiten (Kern)',
    version: '1.4.0',
    author: 'web-cad team',
    description: 'Auswahl, Schraffur, Verschieben, Kopieren, Rotieren, Skalieren, Spiegeln, Löschen, Versatz (V2).',
    category: 'tools',
    enabledByDefault: true,
  },
  tools: [selectTool, hatchTool, moveTool, copyTool, rotateTool, scaleTool, mirrorTool, deleteTool, offsetTool],
};