/**
 * Canvas editor for Scenar Creator v3.
 * Renders schedule blocks on a time-grid canvas with drag & drop via interact.js.
 */

const Canvas = {
    GRID_MINUTES: 15,
    PX_PER_SLOT: 30, // 30px per 15 min
    START_HOUR: 7,
    END_HOUR: 23,

    get pxPerMinute() {
        return this.PX_PER_SLOT / this.GRID_MINUTES;
    },

    get totalSlots() {
        return ((this.END_HOUR - this.START_HOUR) * 60) / this.GRID_MINUTES;
    },

    get totalHeight() {
        return this.totalSlots * this.PX_PER_SLOT;
    },

    minutesToPx(minutes) {
        return (minutes - this.START_HOUR * 60) * this.pxPerMinute;
    },

    pxToMinutes(px) {
        return Math.round(px / this.pxPerMinute + this.START_HOUR * 60);
    },

    snapMinutes(minutes) {
        return Math.round(minutes / this.GRID_MINUTES) * this.GRID_MINUTES;
    },

    formatTime(totalMinutes) {
        const h = Math.floor(totalMinutes / 60);
        const m = totalMinutes % 60;
        return `${String(h).padStart(2, '0')}:${String(m).padStart(2, '0')}`;
    },

    parseTime(str) {
        const [h, m] = str.split(':').map(Number);
        return h * 60 + m;
    },

    isLightColor(hex) {
        const h = hex.replace('#', '');
        const r = parseInt(h.substring(0, 2), 16);
        const g = parseInt(h.substring(2, 4), 16);
        const b = parseInt(h.substring(4, 6), 16);
        return (0.299 * r + 0.587 * g + 0.114 * b) / 255 > 0.6;
    },

    renderTimeAxis() {
        const axis = document.getElementById('timeAxis');
        axis.innerHTML = '';
        axis.style.height = this.totalHeight + 'px';

        for (let slot = 0; slot <= this.totalSlots; slot++) {
            const minutes = this.START_HOUR * 60 + slot * this.GRID_MINUTES;
            const isHour = minutes % 60 === 0;
            const isHalf = minutes % 30 === 0;

            if (isHour || isHalf) {
                const label = document.createElement('div');
                label.className = 'time-label';
                label.style.top = (slot * this.PX_PER_SLOT) + 'px';
                label.textContent = this.formatTime(minutes);
                if (!isHour) {
                    label.style.fontSize = '9px';
                    label.style.opacity = '0.6';
                }
                axis.appendChild(label);
            }
        }
    },

    renderDayColumns(dates) {
        const header = document.getElementById('canvasHeader');
        const columns = document.getElementById('dayColumns');
        header.innerHTML = '';
        columns.innerHTML = '';

        if (dates.length === 0) dates = [new Date().toISOString().split('T')[0]];

        dates.forEach(dateStr => {
            // Header
            const dh = document.createElement('div');
            dh.className = 'day-header';
            dh.textContent = dateStr;
            header.appendChild(dh);

            // Column
            const col = document.createElement('div');
            col.className = 'day-column';
            col.dataset.date = dateStr;
            col.style.height = this.totalHeight + 'px';

            // Grid lines
            for (let slot = 0; slot <= this.totalSlots; slot++) {
                const minutes = this.START_HOUR * 60 + slot * this.GRID_MINUTES;
                const line = document.createElement('div');
                line.className = 'grid-line ' + (minutes % 60 === 0 ? 'hour' : 'half');
                line.style.top = (slot * this.PX_PER_SLOT) + 'px';
                col.appendChild(line);
            }

            // Click area for creating blocks
            const clickArea = document.createElement('div');
            clickArea.className = 'day-column-click-area';
            clickArea.addEventListener('click', (e) => {
                if (e.target !== clickArea) return;
                const rect = col.getBoundingClientRect();
                const y = e.clientY - rect.top;
                const minutes = this.snapMinutes(this.pxToMinutes(y));
                const endMinutes = Math.min(minutes + 60, this.END_HOUR * 60);
                App.createBlock(dateStr, this.formatTime(minutes), this.formatTime(endMinutes));
            });
            col.appendChild(clickArea);

            columns.appendChild(col);
        });
    },

    renderBlocks(blocks, programTypes) {
        // Remove existing blocks
        document.querySelectorAll('.schedule-block').forEach(el => el.remove());

        const typeMap = {};
        programTypes.forEach(pt => { typeMap[pt.id] = pt; });

        blocks.forEach(block => {
            const col = document.querySelector(`.day-column[data-date="${block.date}"]`);
            if (!col) return;

            const pt = typeMap[block.type_id] || { color: '#94a3b8', name: '?' };
            const startMin = this.parseTime(block.start);
            const endMin = this.parseTime(block.end);
            const top = this.minutesToPx(startMin);
            const height = (endMin - startMin) * this.pxPerMinute;
            const isLight = this.isLightColor(pt.color);

            const el = document.createElement('div');
            el.className = 'schedule-block' + (isLight ? ' light-bg' : '');
            el.dataset.blockId = block.id;
            el.style.top = top + 'px';
            el.style.height = Math.max(height, 20) + 'px';
            el.style.backgroundColor = pt.color;

            el.innerHTML = `
                <div class="block-color-bar" style="background:${this.darkenColor(pt.color)}"></div>
                <div class="block-title">${this.escapeHtml(block.title)}</div>
                <div class="block-time">${block.start} – ${block.end}</div>
                ${block.responsible ? `<div class="block-responsible">${this.escapeHtml(block.responsible)}</div>` : ''}
                <div class="resize-handle"></div>
            `;

            // Click to edit
            el.addEventListener('click', (e) => {
                if (e.target.classList.contains('resize-handle')) return;
                App.editBlock(block.id);
            });

            col.appendChild(el);
        });

        this.initInteract();
    },

    initInteract() {
        if (typeof interact === 'undefined') return;

        interact('.schedule-block').draggable({
            inertia: false,
            modifiers: [
                interact.modifiers.snap({
                    targets: [interact.snappers.grid({
                        x: 1, y: this.PX_PER_SLOT
                    })],
                    range: Infinity,
                    relativePoint: { x: 0, y: 0 }
                }),
                interact.modifiers.restrict({
                    restriction: 'parent',
                    elementRect: { top: 0, left: 0, bottom: 1, right: 1 }
                })
            ],
            listeners: {
                start: (event) => {
                    event.target.style.zIndex = 50;
                    event.target.style.opacity = '0.9';
                },
                move: (event) => {
                    const target = event.target;
                    const y = (parseFloat(target.dataset.dragY) || 0) + event.dy;
                    target.dataset.dragY = y;
                    const currentTop = parseFloat(target.style.top) || 0;
                    const newTop = currentTop + event.dy;
                    target.style.top = newTop + 'px';
                },
                end: (event) => {
                    const target = event.target;
                    target.style.zIndex = '';
                    target.style.opacity = '';
                    target.dataset.dragY = 0;

                    const blockId = target.dataset.blockId;
                    const newTop = parseFloat(target.style.top);
                    const height = parseFloat(target.style.height);

                    const startMin = Canvas.snapMinutes(Canvas.pxToMinutes(newTop));
                    const endMin = Canvas.snapMinutes(Canvas.pxToMinutes(newTop + height));

                    App.updateBlockTime(blockId, Canvas.formatTime(startMin), Canvas.formatTime(endMin));
                }
            }
        }).resizable({
            edges: { bottom: '.resize-handle' },
            modifiers: [
                interact.modifiers.snap({
                    targets: [interact.snappers.grid({
                        x: 1, y: this.PX_PER_SLOT
                    })],
                    range: Infinity,
                    relativePoint: { x: 0, y: 0 },
                    offset: 'self'
                }),
                interact.modifiers.restrictSize({
                    min: { width: 0, height: this.PX_PER_SLOT }
                })
            ],
            listeners: {
                move: (event) => {
                    const target = event.target;
                    target.style.height = event.rect.height + 'px';
                },
                end: (event) => {
                    const target = event.target;
                    const blockId = target.dataset.blockId;
                    const top = parseFloat(target.style.top);
                    const height = parseFloat(target.style.height);

                    const startMin = Canvas.snapMinutes(Canvas.pxToMinutes(top));
                    const endMin = Canvas.snapMinutes(Canvas.pxToMinutes(top + height));

                    App.updateBlockTime(blockId, Canvas.formatTime(startMin), Canvas.formatTime(endMin));
                }
            }
        });
    },

    darkenColor(hex) {
        const h = hex.replace('#', '');
        const r = Math.max(0, parseInt(h.substring(0, 2), 16) - 30);
        const g = Math.max(0, parseInt(h.substring(2, 4), 16) - 30);
        const b = Math.max(0, parseInt(h.substring(4, 6), 16) - 30);
        return `rgb(${r},${g},${b})`;
    },

    escapeHtml(str) {
        if (!str) return '';
        const d = document.createElement('div');
        d.textContent = str;
        return d.innerHTML;
    }
};