import { INGREDIENTS, CATEGORY_LABELS } from '../data/catalog.js?v=8';
import {
    KITCHEN_LIST_ID,
    loadShoppingState,
    saveShoppingState,
    addOrMergeShoppingLines,
    removeItemFromList,
    clearCheckedInList,
    loadPantry,
    savePantry,
    computeShortfalls,
    categoryLabel,
} from '../services/pantryShopping.js?v=2';
import { aggregateWeekIngredientNeed } from '../services/planIngredients.js?v=2';
import { loadPlans } from '../services/planStore.js?v=2';
import { startOfWeekMonday } from '../services/dateUtils.js';
import { showAppToast } from '../ui/toast.js';

/* ── helpers ── */

function esc(s) {
    return String(s).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
}

function unitLabel(u) {
    return u === 'szt' ? 'szt.' : u;
}

function formatQty(n) {
    const rounded = Math.round((Number(n) || 0) * 10) / 10;
    return Number.isInteger(rounded) ? String(rounded) : rounded.toFixed(1).replace(/\.0$/, '');
}

const CATEGORY_ICONS = {
    pieczywo: 'fa-bread-slice',
    nabial: 'fa-cheese',
    mieso_ryby: 'fa-drumstick-bite',
    warzywa: 'fa-carrot',
    owoce: 'fa-apple-whole',
    suche: 'fa-wheat-awn',
    przyprawy: 'fa-leaf',
    inne: 'fa-jar',
};

const CATEGORY_ORDER = ['pieczywo', 'nabial', 'mieso_ryby', 'warzywa', 'owoce', 'suche', 'przyprawy', 'inne'];

/* ══════════════════════ HTML SHELL ══════════════════════ */

export function getShoppingListHTML() {
    return `
    <div id="shopping-view" class="hidden flex flex-col h-full absolute inset-0 overflow-hidden z-10" style="background:#2d2e2b !important;">

        <!-- ── header ── -->
        <div class="shrink-0 px-4 pt-5 pb-2">
            <div class="flex items-center justify-between mb-3">
                <h1 class="text-[18px] font-bold" style="color:#f2efe8;">Lista zakupów</h1>
                <button type="button" id="sl-clear-checked" class="text-[11px] font-semibold px-3 py-1.5 rounded-full transition-colors" style="background:#393937; color:#9b978f; border:1px solid #444442;" aria-label="Usuń kupione">
                    Wyczyść kupione
                </button>
            </div>
            <button type="button" id="sl-generate" class="w-full flex items-center justify-center gap-2 py-2.5 rounded-xl text-[13px] font-semibold transition-colors active:scale-[0.98]" style="background:#393937; color:#ddd6ca; border:1px solid #444442;">
                <i class="fas fa-wand-magic-sparkles text-[12px]" style="color:rgb(var(--accent-rgb));"></i>
                Generuj braki z planera
            </button>
        </div>

        <!-- ── scrollable list ── -->
        <div id="sl-scroll" class="flex-1 overflow-y-auto no-scrollbar px-4 pt-2 pb-24" style="background:#2d2e2b !important;">
            <div id="sl-board"></div>
        </div>
    </div>`;
}

/* ══════════════════════ RENDERING ══════════════════════ */

function getKitchenItems() {
    const state = loadShoppingState();
    const list = state.lists.find((l) => l.id === KITCHEN_LIST_ID && l.type === 'kitchen');
    return list ? /** @type {import('../services/pantryShopping.js').KitchenShoppingItem[]} */ (list.items) : [];
}

function groupItemsByCategory(items) {
    /** @type {Map<string, typeof items>} */
    const groups = new Map();
    for (const item of items) {
        const cat = item.category || 'inne';
        if (!groups.has(cat)) groups.set(cat, []);
        groups.get(cat).push(item);
    }
    return CATEGORY_ORDER
        .filter((cat) => groups.has(cat))
        .map((cat) => ({ cat, items: groups.get(cat) }));
}

function itemRowHtml(item) {
    const def = INGREDIENTS[item.ingredientId];
    const icon = def ? (CATEGORY_ICONS[def.category] || 'fa-jar') : 'fa-jar';
    const image = def?.image;
    const checked = item.checked;

    const mediaHtml = image
        ? `<img src="${esc(image)}" alt="" class="w-8 h-8 rounded-lg object-cover shrink-0">`
        : `<div class="w-8 h-8 rounded-lg flex items-center justify-center shrink-0" style="background:#2f2f2d;"><i class="fas ${icon} text-xs" style="color:#8f8b84;"></i></div>`;

    return `
    <div class="sl-row flex items-center gap-3 py-2.5 px-3 rounded-xl mb-1.5 transition-all duration-200 ${checked ? 'sl-checked' : ''}" style="background:${checked ? '#2f2f2d' : '#393937'}; border:1px solid ${checked ? '#3a3a38' : '#444442'};" data-id="${esc(item.id)}">
        <button type="button" class="sl-check shrink-0 w-6 h-6 rounded-full flex items-center justify-center transition-colors" style="background:${checked ? 'rgb(var(--success-rgb))' : 'transparent'}; border:2px solid ${checked ? 'rgb(var(--success-rgb))' : '#6d6c67'};" aria-label="${checked ? 'Oznacz jako niekupione' : 'Oznacz jako kupione'}">
            ${checked ? '<i class="fas fa-check text-[10px]" style="color:#1a1a1a;"></i>' : ''}
        </button>
        ${mediaHtml}
        <div class="flex-1 min-w-0 ${checked ? 'opacity-40' : ''}">
            <span class="block text-[13px] font-medium leading-tight truncate ${checked ? 'line-through' : ''}" style="color:#ddd6ca;">${esc(item.name)}</span>
        </div>
        <span class="text-[13px] font-semibold tabular-nums shrink-0 ${checked ? 'opacity-40 line-through' : ''}" style="color:#b7ada1;">${esc(formatQty(item.amount))} ${esc(unitLabel(item.unit))}</span>
        <button type="button" class="sl-remove shrink-0 w-7 h-7 rounded-full flex items-center justify-center transition-colors" style="background:transparent; color:#6d6c67;" aria-label="Usuń">
            <i class="fas fa-xmark text-xs"></i>
        </button>
    </div>`;
}

function renderBoard() {
    const root = document.getElementById('sl-board');
    if (!root) return;

    const items = getKitchenItems();
    const unchecked = items.filter((i) => !i.checked);
    const checked = items.filter((i) => i.checked);

    if (items.length === 0) {
        root.innerHTML = `
        <div class="flex flex-col items-center justify-center py-16 text-center">
            <div class="w-14 h-14 rounded-2xl flex items-center justify-center mb-4" style="background:#393937;">
                <i class="fas fa-cart-shopping text-xl" style="color:#6d6c67;"></i>
            </div>
            <p class="text-[14px] font-semibold mb-1" style="color:#ddd6ca;">Lista jest pusta</p>
            <p class="text-[12px] max-w-[14rem]" style="color:#9b978f;">Kliknij „Generuj braki z planera" aby dodać składniki na bieżący tydzień.</p>
        </div>`;
        return;
    }

    let html = '';

    // Unchecked items grouped by category
    if (unchecked.length > 0) {
        const groups = groupItemsByCategory(unchecked);
        html += groups.map(({ cat, items: catItems }) => {
            const icon = CATEGORY_ICONS[cat] || 'fa-jar';
            return `
            <section class="mb-4">
                <div class="flex items-center gap-1.5 mb-2 px-1">
                    <i class="fas ${icon} text-[10px]" style="color:#9b978f;"></i>
                    <p class="text-[10px] font-bold uppercase tracking-wider" style="color:#9b978f;">${esc(categoryLabel(cat))}</p>
                    <span class="text-[10px]" style="color:#6d6c67;">${catItems.length}</span>
                </div>
                ${catItems.map((item) => itemRowHtml(item)).join('')}
            </section>`;
        }).join('');
    }

    // Checked items at the bottom
    if (checked.length > 0) {
        html += `
        <section class="mt-4 pt-3" style="border-top:1px solid #3a3a38;">
            <div class="flex items-center gap-1.5 mb-2 px-1">
                <i class="fas fa-check text-[10px]" style="color:#6d6c67;"></i>
                <p class="text-[10px] font-bold uppercase tracking-wider" style="color:#6d6c67;">Kupione</p>
                <span class="text-[10px]" style="color:#6d6c67;">${checked.length}</span>
            </div>
            ${checked.map((item) => itemRowHtml(item)).join('')}
        </section>`;
    }

    root.innerHTML = html;
    bindRowEvents(root);
}

/* ══════════════════════ EVENTS ══════════════════════ */

function bindRowEvents(root) {
    root.querySelectorAll('.sl-row').forEach((row) => {
        const id = row.dataset.id;

        row.querySelector('.sl-check')?.addEventListener('click', () => {
            handleToggle(id);
        });

        row.querySelector('.sl-remove')?.addEventListener('click', () => {
            removeItemFromList(KITCHEN_LIST_ID, id);
            renderBoard();
            updateBadge();
        });
    });
}

function handleToggle(itemId) {
    const state = loadShoppingState();
    const list = state.lists.find((l) => l.id === KITCHEN_LIST_ID);
    if (!list) return;
    const item = list.items.find((i) => i.id === itemId);
    if (!item) return;

    const wasChecked = item.checked;
    item.checked = !wasChecked;
    saveShoppingState(state);

    if (!wasChecked) {
        // Just checked → apply to pantry
        applyItemToPantry(item);
    }

    renderBoard();
    updateBadge();

    if (typeof window.refreshPantry === 'function') window.refreshPantry();
}

function applyItemToPantry(item) {
    const def = INGREDIENTS[item.ingredientId];
    if (!def) return;

    const pantry = loadPantry();

    if (item.productId) {
        let val = pantry[item.ingredientId];
        if (!val || typeof val === 'number') {
            val = { items: [], _total: 0 };
            pantry[item.ingredientId] = val;
        }
        const idx = val.items.findIndex((i) => i.productId === item.productId);
        if (idx >= 0) val.items[idx].qty = Math.round((val.items[idx].qty + item.amount) * 1000) / 1000;
        else val.items.push({ productId: item.productId, qty: Math.round(item.amount * 1000) / 1000 });
        val._total = Math.round(val.items.reduce((s, i) => s + i.qty, 0) * 1000) / 1000;
    } else {
        const cur = typeof pantry[item.ingredientId] === 'number' ? pantry[item.ingredientId] : 0;
        pantry[item.ingredientId] = Math.round((cur + item.amount) * 1000) / 1000;
    }

    savePantry(pantry);
}

function handleGenerate() {
    const plans = loadPlans();
    const weekStart = startOfWeekMonday(new Date());
    const needLines = aggregateWeekIngredientNeed(plans, weekStart);
    const pantry = loadPantry();
    const shortfalls = computeShortfalls(needLines, pantry);

    if (shortfalls.length === 0) {
        showAppToast('Wszystko masz w spiżarni!');
        return;
    }

    const lines = shortfalls.map((s) => ({
        ingredientId: s.ingredientId,
        amount: s.shortfall,
        unit: s.unit,
        name: s.name,
        category: s.category,
        sourceNote: 'Z planera',
    }));

    addOrMergeShoppingLines(lines, KITCHEN_LIST_ID);
    renderBoard();
    updateBadge();
    showAppToast(`Dodano ${shortfalls.length} pozycji z planera`);
}

function handleClearChecked() {
    clearCheckedInList(KITCHEN_LIST_ID);
    renderBoard();
    updateBadge();
}

/* ══════════════════════ BADGE ══════════════════════ */

function updateBadge() {
    const items = getKitchenItems();
    const uncheckedCount = items.filter((i) => !i.checked).length;
    const badge = document.getElementById('nav-shopping-badge');
    if (!badge) return;
    if (uncheckedCount > 0) {
        badge.textContent = String(uncheckedCount > 99 ? '99+' : uncheckedCount);
        badge.classList.remove('hidden');
    } else {
        badge.classList.add('hidden');
    }
}

/* ══════════════════════ PUBLIC API ══════════════════════ */

export function refreshShoppingList() {
    renderBoard();
    updateBadge();
}

export function setupShoppingList() {
    renderBoard();
    updateBadge();

    document.getElementById('sl-generate')?.addEventListener('click', handleGenerate);
    document.getElementById('sl-clear-checked')?.addEventListener('click', handleClearChecked);

    window.refreshShoppingList = refreshShoppingList;
}