/**
 * Main application logic for Scenar Creator v3.
 * State management, UI wiring, modal handling.
 */

const App = {
    state: {
        event: { title: '', subtitle: '', date: '', location: '' },
        program_types: [],
        blocks: []
    },

    init() {
        this.bindEvents();
        this.newScenario();
    },

    // --- State ---

    getDocument() {
        this.syncEventFromUI();
        return {
            version: '1.0',
            event: { ...this.state.event },
            program_types: this.state.program_types.map(pt => ({ ...pt })),
            blocks: this.state.blocks.map(b => ({ ...b }))
        };
    },

    loadDocument(doc) {
        this.state.event = { ...doc.event };
        this.state.program_types = (doc.program_types || []).map(pt => ({ ...pt }));
        this.state.blocks = (doc.blocks || []).map(b => ({
            ...b,
            id: b.id || this.uid()
        }));
        this.syncEventToUI();
        this.renderTypes();
        this.renderCanvas();
    },

    newScenario() {
        const today = new Date().toISOString().split('T')[0];
        this.state = {
            event: { title: 'Nová akce', subtitle: '', date: today, location: '' },
            program_types: [
                { id: 'main', name: 'Hlavní program', color: '#3B82F6' },
                { id: 'rest', name: 'Odpočinek', color: '#22C55E' }
            ],
            blocks: []
        };
        this.syncEventToUI();
        this.renderTypes();
        this.renderCanvas();
    },

    // --- Sync sidebar <-> state ---

    syncEventFromUI() {
        this.state.event.title = document.getElementById('eventTitle').value.trim() || 'Nová akce';
        this.state.event.subtitle = document.getElementById('eventSubtitle').value.trim() || null;
        this.state.event.date = document.getElementById('eventDate').value || null;
        this.state.event.location = document.getElementById('eventLocation').value.trim() || null;
    },

    syncEventToUI() {
        document.getElementById('eventTitle').value = this.state.event.title || '';
        document.getElementById('eventSubtitle').value = this.state.event.subtitle || '';
        document.getElementById('eventDate').value = this.state.event.date || '';
        document.getElementById('eventLocation').value = this.state.event.location || '';
    },

    // --- Program types ---

    renderTypes() {
        const container = document.getElementById('programTypesContainer');
        container.innerHTML = '';
        this.state.program_types.forEach((pt, i) => {
            const row = document.createElement('div');
            row.className = 'type-row';
            row.innerHTML = `
                <input type="color" value="${pt.color}" data-idx="${i}">
                <input type="text" value="${pt.name}" placeholder="Název typu" data-idx="${i}">
                <button class="type-remove" data-idx="${i}">&times;</button>
            `;
            // Color change
            row.querySelector('input[type="color"]').addEventListener('change', (e) => {
                this.state.program_types[i].color = e.target.value;
                this.renderCanvas();
            });
            // Name change
            row.querySelector('input[type="text"]').addEventListener('change', (e) => {
                this.state.program_types[i].name = e.target.value.trim();
            });
            // Remove
            row.querySelector('.type-remove').addEventListener('click', () => {
                this.state.program_types.splice(i, 1);
                this.renderTypes();
                this.renderCanvas();
            });
            container.appendChild(row);
        });
    },

    addType() {
        const id = 'type_' + this.uid().substring(0, 6);
        this.state.program_types.push({
            id,
            name: 'Nový typ',
            color: '#' + Math.floor(Math.random() * 16777215).toString(16).padStart(6, '0')
        });
        this.renderTypes();
    },

    // --- Blocks ---

    createBlock(date, start, end) {
        const typeId = this.state.program_types.length > 0 ? this.state.program_types[0].id : 'main';
        const block = {
            id: this.uid(),
            date: date || this.state.event.date || new Date().toISOString().split('T')[0],
            start: start || '09:00',
            end: end || '10:00',
            title: 'Nový blok',
            type_id: typeId,
            responsible: null,
            notes: null
        };
        this.state.blocks.push(block);
        this.renderCanvas();
        this.editBlock(block.id);
    },

    updateBlockTime(blockId, start, end) {
        const block = this.state.blocks.find(b => b.id === blockId);
        if (block) {
            block.start = start;
            block.end = end;
            this.renderCanvas();
        }
    },

    deleteBlock(blockId) {
        this.state.blocks = this.state.blocks.filter(b => b.id !== blockId);
        this.renderCanvas();
    },

    // --- Canvas rendering ---

    renderCanvas() {
        const dates = this.getUniqueDates();
        Canvas.renderTimeAxis();
        Canvas.renderDayColumns(dates);
        Canvas.renderBlocks(this.state.blocks, this.state.program_types);
    },

    getUniqueDates() {
        const dateSet = new Set();
        this.state.blocks.forEach(b => dateSet.add(b.date));
        if (this.state.event.date) dateSet.add(this.state.event.date);
        const dates = Array.from(dateSet).sort();
        return dates.length > 0 ? dates : [new Date().toISOString().split('T')[0]];
    },

    // --- Modal ---

    editBlock(blockId) {
        const block = this.state.blocks.find(b => b.id === blockId);
        if (!block) return;

        document.getElementById('modalBlockId').value = block.id;
        document.getElementById('modalBlockTitle').value = block.title;
        document.getElementById('modalBlockStart').value = block.start;
        document.getElementById('modalBlockEnd').value = block.end;
        document.getElementById('modalBlockResponsible').value = block.responsible || '';
        document.getElementById('modalBlockNotes').value = block.notes || '';

        // Populate type select
        const select = document.getElementById('modalBlockType');
        select.innerHTML = '';
        this.state.program_types.forEach(pt => {
            const opt = document.createElement('option');
            opt.value = pt.id;
            opt.textContent = pt.name;
            if (pt.id === block.type_id) opt.selected = true;
            select.appendChild(opt);
        });

        document.getElementById('blockModal').classList.remove('hidden');
    },

    saveBlockFromModal() {
        const blockId = document.getElementById('modalBlockId').value;
        const block = this.state.blocks.find(b => b.id === blockId);
        if (!block) return;

        block.title = document.getElementById('modalBlockTitle').value.trim() || 'Blok';
        block.type_id = document.getElementById('modalBlockType').value;
        block.start = document.getElementById('modalBlockStart').value;
        block.end = document.getElementById('modalBlockEnd').value;
        block.responsible = document.getElementById('modalBlockResponsible').value.trim() || null;
        block.notes = document.getElementById('modalBlockNotes').value.trim() || null;

        this.closeModal();
        this.renderCanvas();
    },

    closeModal() {
        document.getElementById('blockModal').classList.add('hidden');
    },

    // --- Toast ---

    toast(message, type) {
        const el = document.getElementById('toast');
        el.textContent = message;
        el.className = 'toast ' + (type || 'info');
        setTimeout(() => el.classList.add('hidden'), 3000);
    },

    // --- PDF ---

    async generatePdf() {
        try {
            const doc = this.getDocument();
            if (doc.blocks.length === 0) {
                this.toast('Přidejte alespoň jeden blok', 'error');
                return;
            }
            const blob = await API.postBlob('/api/generate-pdf', doc);
            API.downloadBlob(blob, 'scenar_timetable.pdf');
            this.toast('PDF vygenerován', 'success');
        } catch (err) {
            this.toast('Chyba: ' + err.message, 'error');
        }
    },

    // --- Utility ---

    uid() {
        return 'xxxx-xxxx-xxxx'.replace(/x/g, () =>
            Math.floor(Math.random() * 16).toString(16)
        );
    },

    // --- Event binding ---

    bindEvents() {
        // Tabs
        document.querySelectorAll('.tab').forEach(tab => {
            tab.addEventListener('click', () => {
                document.querySelectorAll('.tab').forEach(t => t.classList.remove('active'));
                document.querySelectorAll('.tab-content').forEach(c => c.classList.add('hidden'));
                tab.classList.add('active');
                document.getElementById('tab-' + tab.dataset.tab).classList.remove('hidden');
            });
        });

        // Header buttons
        document.getElementById('newScenarioBtn').addEventListener('click', () => this.newScenario());
        document.getElementById('exportJsonBtn').addEventListener('click', () => exportJson());
        document.getElementById('generatePdfBtn').addEventListener('click', () => this.generatePdf());

        // Import JSON
        document.getElementById('importJsonInput').addEventListener('change', (e) => {
            if (e.target.files[0]) importJson(e.target.files[0]);
            e.target.value = '';
        });

        // Sidebar
        document.getElementById('addTypeBtn').addEventListener('click', () => this.addType());
        document.getElementById('addBlockBtn').addEventListener('click', () => this.createBlock());

        // Modal
        document.getElementById('modalSaveBtn').addEventListener('click', () => this.saveBlockFromModal());
        document.getElementById('modalClose').addEventListener('click', () => this.closeModal());
        document.getElementById('modalDeleteBtn').addEventListener('click', () => {
            const blockId = document.getElementById('modalBlockId').value;
            this.closeModal();
            this.deleteBlock(blockId);
        });

        // Close modal on overlay click
        document.getElementById('blockModal').addEventListener('click', (e) => {
            if (e.target.classList.contains('modal-overlay')) this.closeModal();
        });

        // Drag & drop JSON on canvas
        const canvasWrapper = document.querySelector('.canvas-wrapper');
        if (canvasWrapper) {
            canvasWrapper.addEventListener('dragover', (e) => e.preventDefault());
            canvasWrapper.addEventListener('drop', (e) => {
                e.preventDefault();
                const file = e.dataTransfer.files[0];
                if (file && file.name.endsWith('.json')) {
                    importJson(file);
                }
            });
        }
    }
};

// Boot
document.addEventListener('DOMContentLoaded', () => App.init());