'use strict';

(function() {
    const overlay    = document.getElementById('crop-modal-overlay');
    const BELEG_ID   = overlay.dataset.belegId;
    const FILE_URL   = '/belege/' + BELEG_ID + '/file';
    const canvas     = document.getElementById('crop-canvas');
    const confirmBtn = document.getElementById('crop-confirm-btn');
    const sizeHint   = document.getElementById('crop-size-hint');
    const ctx        = canvas.getContext('2d');

    let img = null;
    let scaleX = 1, scaleY = 1;
    let sel = null;       // {x,y,w,h} in Canvas-Koordinaten
    let dragging = false;
    let startX = 0, startY = 0;

    const spinner = document.getElementById('crop-spinner');

    window.openCropModal = function() {
        overlay.style.display = 'flex';
        if (img) { drawCanvas(); return; }

        spinner.style.display = 'flex';
        img = new Image();
        img.onload = function() {
            // Canvas auf max. 90vw / 72vh skalieren
            const maxW = Math.min(window.innerWidth  * 0.90, 1200);
            const maxH = Math.min(window.innerHeight * 0.72, 900);
            const ratio = Math.min(maxW / img.naturalWidth, maxH / img.naturalHeight, 1);
            canvas.width  = Math.round(img.naturalWidth  * ratio);
            canvas.height = Math.round(img.naturalHeight * ratio);
            scaleX = img.naturalWidth  / canvas.width;
            scaleY = img.naturalHeight / canvas.height;
            sel = null;
            spinner.style.display = 'none';
            drawCanvas();
        };
        img.src = FILE_URL + '?nocache=' + Date.now();
    };

    window.closeCropModal = function() {
        overlay.style.display = 'none';
    };

    function drawCanvas() {
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
        if (!sel || sel.w === 0 || sel.h === 0) return;

        // Abdunkeln außerhalb der Auswahl
        ctx.fillStyle = 'rgba(0,0,0,0.45)';
        ctx.fillRect(0, 0, canvas.width, canvas.height);

        // Ausschnitt freistellen
        ctx.drawImage(img,
            sel.x * scaleX, sel.y * scaleY, sel.w * scaleX, sel.h * scaleY,
            sel.x, sel.y, sel.w, sel.h);

        // Rahmen
        ctx.strokeStyle = '#fff';
        ctx.lineWidth   = 1.5;
        ctx.setLineDash([5, 3]);
        ctx.strokeRect(sel.x + 0.5, sel.y + 0.5, sel.w, sel.h);
        ctx.setLineDash([]);

        const realW = Math.round(sel.w * scaleX);
        const realH = Math.round(sel.h * scaleY);
        sizeHint.textContent = realW + ' × ' + realH + ' px';
        confirmBtn.disabled  = (realW < 10 || realH < 10);
    }

    function canvasPos(e) {
        const r = canvas.getBoundingClientRect();
        const cx = e.touches ? e.touches[0].clientX : e.clientX;
        const cy = e.touches ? e.touches[0].clientY : e.clientY;
        return {
            x: Math.max(0, Math.min(canvas.width,  Math.round(cx - r.left))),
            y: Math.max(0, Math.min(canvas.height, Math.round(cy - r.top))),
        };
    }

    canvas.addEventListener('mousedown',  startDrag);
    canvas.addEventListener('touchstart', startDrag, {passive: true});

    function startDrag(e) {
        const p = canvasPos(e);
        startX  = p.x; startY = p.y;
        sel     = {x: p.x, y: p.y, w: 0, h: 0};
        dragging = true;
        confirmBtn.disabled = true;
        sizeHint.textContent = '';
    }

    window.addEventListener('mousemove',  moveDrag);
    window.addEventListener('touchmove',  moveDrag, {passive: true});

    function moveDrag(e) {
        if (!dragging) return;
        const p = canvasPos(e);
        sel = {
            x: Math.min(startX, p.x),
            y: Math.min(startY, p.y),
            w: Math.abs(p.x - startX),
            h: Math.abs(p.y - startY),
        };
        drawCanvas();
    }

    window.addEventListener('mouseup',  endDrag);
    window.addEventListener('touchend', endDrag);

    function endDrag() { dragging = false; }

    window.confirmCrop = async function() {
        if (!sel || sel.w < 1 || sel.h < 1) return;
        confirmBtn.disabled = true;
        confirmBtn.textContent = 'Wird gespeichert…';

        const payload = {
            x: Math.round(sel.x * scaleX),
            y: Math.round(sel.y * scaleY),
            w: Math.round(sel.w * scaleX),
            h: Math.round(sel.h * scaleY),
        };

        try {
            const res = await fetch('/belege/' + BELEG_ID + '/crop', {
                method: 'POST',
                headers: {'Content-Type': 'application/json'},
                body: JSON.stringify(payload),
            });
            const data = await res.json();
            if (!res.ok) throw new Error(data.error || 'Unbekannter Fehler');
            location.reload();
        } catch (err) {
            alert('Fehler beim Zuschneiden: ' + err.message);
            confirmBtn.disabled  = false;
            confirmBtn.textContent = 'Zuschnitt übernehmen';
        }
    };

    // ESC schließt Modal
    document.addEventListener('keydown', function(e) {
        if (e.key === 'Escape' && overlay.style.display !== 'none') closeCropModal();
    });

    // Klick auf Overlay-Hintergrund schließt
    overlay.addEventListener('click', function(e) {
        if (e.target === overlay) closeCropModal();
    });

    confirmBtn.addEventListener('click', function () { confirmCrop(); });
    const cancelBtn = document.getElementById('crop-cancel-btn');
    if (cancelBtn) cancelBtn.addEventListener('click', function () { closeCropModal(); });
}());