/*
 * Bericht-Editor — PDF.js + Fabric.js + SortableJS
 * Lädt Seiten via /ajax/page_image.php (Bilder direkt, PDFs via PDF.js gerendert),
 * legt Fabric.js-Canvas darüber, speichert Annotationen pro Seite über Ajax.
 *
 * Erwartet im DOM:
 *   #pdf-canvas         — Canvas für die Seitendarstellung
 *   #fabric-canvas      — Overlay-Canvas für Annotationen
 *   #bericht-page-list  — Container für Seiten-Thumbnails (.page-thumb[data-pageid])
 *   #page-note          — Textarea für Seiten-Notiz
 *   .att-check          — Checkboxen der Anhänge-Liste
 *   #btn-add-selected   — Button "Auswahl in Bericht übernehmen"
 *   #btn-save-draft     — Entwurf speichern
 *   #btn-finalize       — Bericht finalisieren
 *   #btn-undo / #btn-redo / #btn-delete-selected
 *   .tool-btn[data-tool]
 *   #tool-color, #tool-stroke
 *   #bericht-extra-upload (file input)
 *
 * Globale Konfiguration: window.BERICHT_CONFIG (vom PHP gesetzt)
 */

(function () {
    'use strict';

    const cfg = window.BERICHT_CONFIG || {};
    if (!cfg.berichtid) { console.warn('Bericht: keine Konfiguration'); return; }

    // PDF.js worker (lokal)
    if (window.pdfjsLib) {
        pdfjsLib.GlobalWorkerOptions.workerSrc = '/bericht/js/lib/pdf.worker.min.js';
    }

    let currentPageId = null;
    let currentPageEl = null;
    let currentPageRotation = 0;          // 0 / 90 / 180 / 270
    let currentPageBuffer = null;         // ArrayBuffer der aktuellen Quelle
    let currentPageMime = '';
    let fabricCanvas = null;
    const pdfCanvas = document.getElementById('pdf-canvas');
    let currentTool = 'select';

    /* ---------- Init ---------- */
    function init() {
        // Fabric initialisieren (wird beim ersten Seitenrendern dimensioniert)
        fabricCanvas = new fabric.Canvas('fabric-canvas', {
            isDrawingMode: false,
            selection: true,
        });
        fabricCanvas.freeDrawingBrush.color = document.getElementById('tool-color').value;
        fabricCanvas.freeDrawingBrush.width = parseInt(document.getElementById('tool-stroke').value, 10);

        // Erste Seite laden (wenn vorhanden)
        const firstThumb = document.querySelector('#bericht-page-list .page-thumb');
        if (firstThumb) loadPage(firstThumb);

        bindThumbs();
        bindToolbar();
        bindAttachments();
        bindExtraUpload();
        bindActions();
        bindSortable();
    }

    /* ---------- Seiten laden ---------- */
    async function loadPage(thumbEl) {
        // vorher: aktuelle Seite speichern
        if (currentPageId) await savePageAnnotations(false);

        currentPageEl = thumbEl;
        currentPageId = parseInt(thumbEl.dataset.pageid, 10);

        document.querySelectorAll('.page-thumb.active').forEach(e => e.classList.remove('active'));
        thumbEl.classList.add('active');

        const url = cfg.urls.page_image + '?pageid=' + currentPageId;
        const resp = await fetch(url);
        const ct = resp.headers.get('Content-Type') || '';
        const buf = await resp.arrayBuffer();

        currentPageBuffer = buf;
        currentPageMime = ct;
        currentPageRotation = 0; // wird gleich aus loadPageMeta überschrieben falls gespeichert

        fabricCanvas.clear();
        document.getElementById('page-note').value = '';

        await loadPageMeta();        // setzt currentPageRotation falls vorhanden
        await rerenderCurrent();     // rendert mit Rotation
    }

    /**
     * Rendert die aktuelle Seite (image oder pdf) aus dem Buffer mit currentPageRotation.
     */
    async function rerenderCurrent() {
        if (!currentPageBuffer) return;
        if (currentPageMime.includes('pdf')) {
            await renderPdf(currentPageBuffer);
        } else if (currentPageMime.includes('image')) {
            await renderImage(currentPageBuffer, currentPageMime);
        }
    }

    /**
     * Liefert die nutzbare Breite des Canvas-Containers (minus Padding).
     * Begrenzt auf 1200px, damit auch auf großen Screens nicht alles riesig wird.
     */
    function getTargetCanvasWidth() {
        const wrap = document.querySelector('.bericht-canvas-wrap');
        if (!wrap) return 800;
        const cs = getComputedStyle(wrap);
        const padX = parseFloat(cs.paddingLeft) + parseFloat(cs.paddingRight);
        const avail = wrap.clientWidth - padX - 4; // 4px Sicherheitsabstand
        return Math.max(300, Math.min(1200, Math.floor(avail)));
    }

    async function renderPdf(arrayBuffer) {
        if (!window.pdfjsLib) { console.error('PDF.js nicht geladen'); return; }
        // Buffer kopieren — pdf.js konsumiert den ArrayBuffer beim ersten Aufruf
        const pdfDoc = await pdfjsLib.getDocument({ data: arrayBuffer.slice(0) }).promise;
        const pageNum = 1;
        const page = await pdfDoc.getPage(pageNum);
        // Bei Rotation müssen wir die orientierte Breite messen, um auf den
        // Container zu passen
        const target = getTargetCanvasWidth();
        const baseViewport = page.getViewport({ scale: 1, rotation: currentPageRotation });
        const scale = target / baseViewport.width;
        const viewport = page.getViewport({ scale: scale, rotation: currentPageRotation });
        pdfCanvas.width = viewport.width;
        pdfCanvas.height = viewport.height;
        const ctx = pdfCanvas.getContext('2d');
        await page.render({ canvasContext: ctx, viewport: viewport }).promise;
        resizeFabricToCanvas();
    }

    async function renderImage(arrayBuffer, mime) {
        const blob = new Blob([arrayBuffer], { type: mime });
        const url = URL.createObjectURL(blob);
        await new Promise((res) => {
            const img = new Image();
            img.onload = () => {
                const target = getTargetCanvasWidth();
                // Bei 90/270° werden Breite und Höhe getauscht
                const rotated = (currentPageRotation === 90 || currentPageRotation === 270);
                const srcW = rotated ? img.height : img.width;
                const srcH = rotated ? img.width  : img.height;
                const ratio = target / srcW;
                pdfCanvas.width  = Math.round(srcW * ratio);
                pdfCanvas.height = Math.round(srcH * ratio);

                const ctx = pdfCanvas.getContext('2d');
                ctx.clearRect(0, 0, pdfCanvas.width, pdfCanvas.height);
                ctx.save();
                ctx.translate(pdfCanvas.width / 2, pdfCanvas.height / 2);
                ctx.rotate(currentPageRotation * Math.PI / 180);
                const dw = img.width  * ratio;
                const dh = img.height * ratio;
                ctx.drawImage(img, -dw / 2, -dh / 2, dw, dh);
                ctx.restore();

                URL.revokeObjectURL(url);
                res();
            };
            img.src = url;
        });
        resizeFabricToCanvas();
    }

    function resizeFabricToCanvas() {
        // Die tatsächlich angezeigte Größe (nicht der Drawing-Buffer) bestimmt
        // die Position des Fabric-Overlays. Wir setzen das Fabric-Canvas auf
        // die Buffer-Größe (für scharfe Annotationen) und positionieren es
        // exakt über dem sichtbaren PDF-Canvas.
        fabricCanvas.setWidth(pdfCanvas.width);
        fabricCanvas.setHeight(pdfCanvas.height);

        // Warten bis der Browser die neue Größe applied hat
        requestAnimationFrame(() => {
            const rect = pdfCanvas.getBoundingClientRect();
            const wrap = pdfCanvas.parentElement;
            const wrapRect = wrap.getBoundingClientRect();
            const fc = document.getElementById('fabric-canvas');
            fc.style.position = 'absolute';
            fc.style.left   = (rect.left - wrapRect.left + wrap.scrollLeft) + 'px';
            fc.style.top    = (rect.top  - wrapRect.top  + wrap.scrollTop)  + 'px';
            fc.style.width  = pdfCanvas.clientWidth  + 'px';
            fc.style.height = pdfCanvas.clientHeight + 'px';
        });
    }

    async function loadPageMeta() {
        try {
            const r = await fetch(cfg.urls.save_annotations.replace('save_annotations', 'page_meta') + '?pageid=' + currentPageId);
            if (!r.ok) return;
            const data = await r.json();
            if (data.fabric_json) {
                fabricCanvas.loadFromJSON(data.fabric_json, () => fabricCanvas.renderAll());
            }
            if (data.note) document.getElementById('page-note').value = data.note;
            if (typeof data.rotation !== 'undefined' && data.rotation !== null) {
                currentPageRotation = parseInt(data.rotation, 10) || 0;
            }
        } catch (e) { /* ok */ }
    }

    /* ---------- Toolbar ---------- */
    function bindToolbar() {
        document.querySelectorAll('.tool-btn').forEach(btn => {
            btn.addEventListener('click', () => {
                document.querySelectorAll('.tool-btn.active').forEach(b => b.classList.remove('active'));
                btn.classList.add('active');
                currentTool = btn.dataset.tool;
                applyTool();
            });
        });

        document.getElementById('tool-color').addEventListener('input', e => {
            fabricCanvas.freeDrawingBrush.color = e.target.value;
            const sel = fabricCanvas.getActiveObject();
            if (sel) {
                sel.set({ stroke: e.target.value });
                if (sel.type === 'i-text' || sel.type === 'text') sel.set({ fill: e.target.value });
                fabricCanvas.requestRenderAll();
            }
        });
        document.getElementById('tool-stroke').addEventListener('input', e => {
            fabricCanvas.freeDrawingBrush.width = parseInt(e.target.value, 10);
            const sel = fabricCanvas.getActiveObject();
            if (sel) { sel.set({ strokeWidth: parseInt(e.target.value, 10) }); fabricCanvas.requestRenderAll(); }
        });

        document.getElementById('btn-undo').addEventListener('click', undo);
        document.getElementById('btn-redo').addEventListener('click', redo);
        document.getElementById('btn-delete-selected').addEventListener('click', () => {
            const sel = fabricCanvas.getActiveObjects();
            sel.forEach(o => fabricCanvas.remove(o));
            fabricCanvas.discardActiveObject();
            fabricCanvas.requestRenderAll();
        });
        // Seitenrotation: rotate-left/right rotieren die SEITE (nicht das Fabric-Objekt)
        document.getElementById('btn-rotate-left').addEventListener('click', () => rotatePage(-90));
        document.getElementById('btn-rotate-right').addEventListener('click', () => rotatePage(90));
    }

    async function rotatePage(deg) {
        currentPageRotation = ((currentPageRotation + deg) % 360 + 360) % 360;
        // Annotationen für die alte Orientierung sind im JSON noch da — wir werfen
        // sie vor dem Re-Render weg, damit sie nicht falsch positioniert sind.
        // (Bewusste Designentscheidung: rotieren vor dem Annotieren.)
        fabricCanvas.clear();
        await rerenderCurrent();
        // Sofort speichern, damit Rotation persistent ist
        await savePageAnnotations(false);
    }

    function applyTool() {
        fabricCanvas.isDrawingMode = (currentTool === 'draw');
        fabricCanvas.selection = (currentTool === 'select');

        // Click-Handler für Shape-Tools
        fabricCanvas.off('mouse:down', shapeDown);
        if (['rect', 'circle', 'arrow', 'text'].includes(currentTool)) {
            fabricCanvas.on('mouse:down', shapeDown);
        }
    }

    function shapeDown(opt) {
        const p = fabricCanvas.getPointer(opt.e);
        const color = document.getElementById('tool-color').value;
        const sw = parseInt(document.getElementById('tool-stroke').value, 10);
        let shape = null;
        if (currentTool === 'rect') {
            shape = new fabric.Rect({ left: p.x, top: p.y, width: 100, height: 60, fill: 'transparent', stroke: color, strokeWidth: sw });
        } else if (currentTool === 'circle') {
            shape = new fabric.Circle({ left: p.x, top: p.y, radius: 40, fill: 'transparent', stroke: color, strokeWidth: sw });
        } else if (currentTool === 'arrow') {
            // Pfeil = Linie mit Pfeilspitze (vereinfacht)
            shape = new fabric.Line([p.x, p.y, p.x + 100, p.y + 50], { stroke: color, strokeWidth: sw });
        } else if (currentTool === 'text') {
            shape = new fabric.IText('Text…', { left: p.x, top: p.y, fontSize: 24, fill: color });
        }
        if (shape) {
            fabricCanvas.add(shape);
            fabricCanvas.setActiveObject(shape);
            // Nach dem Setzen wieder zurück auf Select, damit User direkt verschieben/skalieren kann
            const sb = document.querySelector('.tool-btn[data-tool="select"]');
            if (sb) sb.click();
        }
    }

    /* ---------- Undo/Redo (einfach) ---------- */
    const history = [];
    let histIdx = -1;
    function snapshot() {
        history.length = histIdx + 1;
        history.push(JSON.stringify(fabricCanvas.toJSON()));
        histIdx = history.length - 1;
    }
    function undo() {
        if (histIdx <= 0) return;
        histIdx--;
        fabricCanvas.loadFromJSON(history[histIdx], () => fabricCanvas.renderAll());
    }
    function redo() {
        if (histIdx >= history.length - 1) return;
        histIdx++;
        fabricCanvas.loadFromJSON(history[histIdx], () => fabricCanvas.renderAll());
    }
    setTimeout(() => {
        if (fabricCanvas) {
            fabricCanvas.on('object:added', snapshot);
            fabricCanvas.on('object:modified', snapshot);
            fabricCanvas.on('object:removed', snapshot);
        }
    }, 500);

    function rotateCurrent(deg) {
        const sel = fabricCanvas.getActiveObject();
        if (sel) {
            sel.rotate(((sel.angle || 0) + deg) % 360);
            fabricCanvas.requestRenderAll();
        }
    }

    /* ---------- Speichern ---------- */
    async function savePageAnnotations(showMessage = true) {
        if (!currentPageId) return;
        const fd = new FormData();
        fd.append('token', cfg.token);
        fd.append('pageid', currentPageId);
        fd.append('fabric_json', JSON.stringify(fabricCanvas.toJSON()));
        fd.append('note', document.getElementById('page-note').value || '');
        fd.append('rotation', currentPageRotation);
        const r = await fetch(cfg.urls.save_annotations, { method: 'POST', body: fd });
        const data = await r.json().catch(() => ({}));
        if (showMessage && data.success) toast('Seite gespeichert');
    }

    function bindActions() {
        document.getElementById('btn-save-draft').addEventListener('click', async () => {
            await savePageAnnotations(true);
        });
        document.getElementById('btn-finalize').addEventListener('click', async () => {
            await savePageAnnotations(false);
            const fd = new FormData();
            fd.append('token', cfg.token);
            fd.append('berichtid', cfg.berichtid);
            const r = await fetch(cfg.urls.generate_pdf, { method: 'POST', body: fd });
            const data = await r.json();
            if (data.success) {
                toast('PDF erstellt: ' + data.filename);
                setTimeout(() => location.reload(), 1500);
            } else {
                alert('Fehler: ' + (data.error || 'unbekannt'));
            }
        });
    }

    /* ---------- Anhänge & Thumbs ---------- */
    function bindAttachments() {
        const btn = document.getElementById('btn-add-selected');
        if (!btn) return;
        btn.addEventListener('click', async () => {
            const checks = document.querySelectorAll('.att-check:checked');
            for (const c of checks) {
                const fd = new FormData();
                fd.append('token', cfg.token);
                fd.append('berichtid', cfg.berichtid);
                fd.append('relpath', c.dataset.relpath);
                fd.append('mime', c.dataset.mime);
                await fetch(cfg.urls.add_attachment, { method: 'POST', body: fd });
                c.checked = false;
            }
            location.reload(); // einfacher als Thumbnail-Liste neu zu rendern
        });
    }

    function bindExtraUpload() {
        const inp = document.getElementById('bericht-extra-upload');
        if (!inp) return;
        inp.addEventListener('change', async () => {
            if (!inp.files.length) return;
            const fd = new FormData();
            fd.append('token', cfg.token);
            fd.append('berichtid', cfg.berichtid);
            fd.append('file', inp.files[0]);
            const r = await fetch(cfg.urls.upload_extra, { method: 'POST', body: fd });
            const data = await r.json();
            if (data.success) location.reload();
            else alert('Upload fehlgeschlagen: ' + (data.error || ''));
        });
    }

    function bindThumbs() {
        document.querySelectorAll('.page-thumb').forEach(t => {
            t.addEventListener('click', e => {
                if (e.target.closest('.thumb-del')) return;
                loadPage(t);
            });
            const del = t.querySelector('.thumb-del');
            if (del) del.addEventListener('click', async (e) => {
                e.stopPropagation();
                if (!confirm(cfg.lang.confirm_del)) return;
                const fd = new FormData();
                fd.append('token', cfg.token);
                fd.append('pageid', t.dataset.pageid);
                await fetch(cfg.urls.delete_page, { method: 'POST', body: fd });
                location.reload();
            });
        });
    }

    function bindSortable() {
        const list = document.getElementById('bericht-page-list');
        if (!list || !window.Sortable) return;
        Sortable.create(list, {
            animation: 150,
            onEnd: async () => {
                const ids = Array.from(list.querySelectorAll('.page-thumb')).map(t => t.dataset.pageid);
                const fd = new FormData();
                fd.append('token', cfg.token);
                fd.append('order', JSON.stringify(ids));
                await fetch(cfg.urls.reorder_pages, { method: 'POST', body: fd });
            }
        });
    }

    /* ---------- Helpers ---------- */
    function toast(msg) {
        const t = document.createElement('div');
        t.className = 'bericht-toast';
        t.textContent = msg;
        document.body.appendChild(t);
        setTimeout(() => t.remove(), 2000);
    }

    document.addEventListener('DOMContentLoaded', init);
})();