/**
 * Task G2 – LayoutBar: Layout-Verwaltung + Viewport-Minimap-Widget.
 *
 * - Listet Layouts des aktiven Dokuments (documentService-Fallback)
 * - Klick auf Eintrag = zoom-to gespeichertem Viewport (Bridge)
 * - „+“ speichert aktuellen Viewport als neues Layout
 * - „🗑“ löscht Layout; je Eintrag Minimap (Modellbereich + Viewport-Rechteck)
 */
import React, { useCallback, useEffect, useState } from 'react';
import type { LayoutDefinition } from '../types/cad.types';
import { getActiveDocument, onActiveDocumentChanged } from '../kernel/document/documentService';
import { insertTitleBlockForLayout } from '../services/titleBlockService';
import { printLayout } from '../services/printService';
import { useT } from '../i18n/strings';

export interface LayoutView {
  center: { x: number; y: number };
  scale: number;
}

export interface LayoutBridge {
  zoomTo(center: { x: number; y: number }, scale: number): void;
  getView(): LayoutView;
}

interface LayoutBarProps {
  /** Aktives Dokument (Fallback: documentService, Task G2 UI-Unabhängigkeit). */
  doc?: {
    getAllLayouts(): LayoutDefinition[];
    addLayout(l: LayoutDefinition): void;
    deleteLayout(id: string): void;
    getAllElements?(): Array<{ x: number; y: number; width: number; height: number }>;
    onChanged?(cb: () => void): () => void;
  } | null;
  /** Canvas-Bridge (Fallback: window.__v2LayoutBridge aus CanvasArea). */
  bridge?: LayoutBridge | null;
}

interface Rect { x: number; y: number; w: number; h: number }

/**
 * Minimap-Geometrie (Task G2, rein & getestet):
 * Modell-BBox füllt das Widget (Stretch mit 6px Padding); ohne Elemente
 * Volles Widget. Viewport-Rechteck = nominale Ansicht 800×600/scale Welt.
 */
export function computeMinimapRects(
  elements: Array<{ x: number; y: number; width: number; height: number }>,
  view: LayoutView,
  widgetW: number,
  widgetH: number,
): { model: Rect; view: Rect } {
  if (!Array.isArray(elements) || elements.length === 0) {
    return { model: { x: 0, y: 0, w: widgetW, h: widgetH }, view: { x: 0, y: 0, w: widgetW, h: widgetH } };
  }
  let minX = Infinity, minY = Infinity, maxX = -Infinity, maxY = -Infinity;
  for (const el of elements) {
    minX = Math.min(minX, el.x - el.width / 2);
    minY = Math.min(minY, el.y - el.height / 2);
    maxX = Math.max(maxX, el.x + el.width / 2);
    maxY = Math.max(maxY, el.y + el.height / 2);
  }
  if (!isFinite(minX) || maxX - minX <= 0 || maxY - minY <= 0) {
    return { model: { x: 0, y: 0, w: widgetW, h: widgetH }, view: { x: 0, y: 0, w: widgetW, h: widgetH } };
  }
  const PAD = 6;
  const model: Rect = { x: PAD, y: PAD, w: widgetW - 2 * PAD, h: widgetH - 2 * PAD };
  const wx = (w: number) => model.x + ((w - minX) / (maxX - minX)) * model.w;
  const wy = (w: number) => model.y + ((w - minY) / (maxY - minY)) * model.h;
  const viewW = 800 / view.scale;
  const viewH = 600 / view.scale;
  const viewRect: Rect = {
    x: wx(view.center.x - viewW / 2),
    y: wy(view.center.y - viewH / 2),
    w: (viewW / (maxX - minX)) * model.w,
    h: (viewH / (maxY - minY)) * model.h,
  };
  return { model, view: viewRect };
}

const WIDGET_W = 100;
const WIDGET_H = 80;

const LayoutBar: React.FC<LayoutBarProps> = ({ doc: docProp, bridge: bridgeProp }) => {
  const t = useT();

  const [doc, setDoc] = useState(docProp ?? getActiveDocument());
  const [layouts, setLayouts] = useState<LayoutDefinition[]>([]);

  const bridge: LayoutBridge | null = bridgeProp ??
    ((typeof window !== 'undefined' ? (window as unknown as { __v2LayoutBridge?: LayoutBridge }).__v2LayoutBridge : undefined) ?? null);

  const reload = useCallback(() => {
    setLayouts(doc ? doc.getAllLayouts() : []);
  }, [doc]);

  useEffect(() => {
    reload();
    // Live-Updates (auch Remote via CRDT), falls das Doc es anbietet
    const off = doc?.onChanged?.(reload);
    return () => { if (off) off(); };
  }, [reload]);

  // Fallback-Verdrahtung: aktives Dokument aus dem documentService
  useEffect(() => {
    if (docProp) return;
    setDoc(getActiveDocument());
    const off = onActiveDocumentChanged(() => setDoc(getActiveDocument()));
    return off;
  }, [docProp]);

  const handleAdd = () => {
    if (!bridge || !doc) return;
    const view = bridge.getView();
    doc.addLayout({
      id: `layout-${Date.now()}`,
      name: `Layout ${layouts.length + 1}`,
      viewport: { center: { ...view.center }, scale: view.scale },
    });
    reload();
  };

  const handleDelete = (id: string) => {
    doc?.deleteLayout(id);
    reload();
  };

  const handlePrint = () => {
    void printLayout();
  };

  const handleZoomTo = (l: LayoutDefinition) => {
    bridge?.zoomTo(l.viewport.center, l.viewport.scale);
  };

  const elements = doc?.getAllElements?.() ?? [];

  return (
    <div className="layout-bar" data-testid="layout-bar">
      <div className="layout-bar-header">
        <span className="layout-bar-title">{t('layouts.title')}</span>
        <button
          type="button"
          className="layout-bar-add"
          title={t('layouts.add')}
          onClick={handleAdd}
          disabled={!bridge || !doc}
        >+</button>
        <button
          type="button"
          className="layout-bar-print screen-only"
          title={t('layouts.print')}
          onClick={handlePrint}
        >🖨</button>
      </div>
      {layouts.length === 0 ? (
        <div className="layout-bar-empty">{t('layouts.empty')}</div>
      ) : (
        <div className="layout-bar-list">
          {layouts.map((l) => {
            const rects = computeMinimapRects(elements, l.viewport, WIDGET_W, WIDGET_H);
            return (
              <div key={l.id} className="layout-bar-item">
                <button
                  type="button"
                  className="layout-bar-entry"
                  data-testid={`layout-entry-${l.id}`}
                  title={t('layouts.zoomto', l.name)}
                  onClick={() => handleZoomTo(l)}
                >
                  <svg
                    data-testid={`layout-minimap-${l.id}`}
                    width={WIDGET_W}
                    height={WIDGET_H}
                    viewBox={`0 0 ${WIDGET_W} ${WIDGET_H}`}
                    className="layout-minimap"
                  >
                    <rect
                      x={rects.model.x} y={rects.model.y}
                      width={rects.model.w} height={rects.model.h}
                      fill="rgba(255,255,255,0.05)" stroke="rgba(255,255,255,0.25)" strokeWidth="1"
                    />
                    <rect
                      x={rects.view.x} y={rects.view.y}
                      width={Math.max(2, rects.view.w)} height={Math.max(2, rects.view.h)}
                      fill="rgba(74,144,217,0.25)" stroke="#4a90d9" strokeWidth="1"
                    />
                  </svg>
                  <span className="layout-bar-name">{l.name}</span>
                </button>
                <button
                  type="button"
                  className="layout-bar-tb"
                  title={t('layouts.titleblock', l.name)}
                  onClick={() => {
                    if (!doc) return;
                    insertTitleBlockForLayout(doc as never, l.id, {
                      project: l.name,
                      date: new Date().toISOString().slice(0, 10),
                      scale: `1:${Math.max(1, Math.round(1 / (l.viewport.scale || 1)))}`,
                      author: 'WebCAD',
                    });
                    reload();
                  }}
                >🏷</button>
                <button
                  type="button"
                  className="layout-bar-del"
                  title={t('layouts.delete', l.name)}
                  onClick={() => handleDelete(l.id)}
                >🗑</button>
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
};

export default LayoutBar;