// Shared LOT price-quality indicator, used everywhere price_quality is
// displayed (pricelist detail page, configurator search dropdown, configurator
// table, pricing tab). price_quality is a 0-9 score set by the external pricing
// tool (see bible-local/03-database.md, qt_pricelist_items.price_quality) — QF
// only displays it, never computes it. Single source of the visual scale so
// every view stays consistent.
//
// Two render modes, chosen per client via window.QF_INDICATOR_MODE (injected by
// base.html from app_settings, key indicator_mode):
//   "color" (default) — hue scale, 0 = red, 5 = yellow, 9 = green.
//   "accessible"      — colour-blind-safe 5-step signal-strength meter,
//                       single neutral hue, magnitude encoded by bar count.
// See bible-local/decisions/2026-08-31-accessible-indicator-mode.md.
(function () {
    const RED = [220, 38, 38];
    const YELLOW = [234, 179, 8];
    const GREEN = [22, 163, 74];

    function isAccessible() {
        return window.QF_INDICATOR_MODE === 'accessible';
    }

    function lerp(c1, c2, t) {
        return c1.map((v, i) => Math.round(v + (c2[i] - v) * t));
    }

    // Returns "r, g, b" (no rgb() wrapper) so callers can build rgb()/rgba() themselves.
    function priceQualityRgb(quality) {
        if (typeof quality !== 'number' || Number.isNaN(quality)) return null;
        const q = Math.max(0, Math.min(9, quality));
        const [r, g, b] = q <= 5 ? lerp(RED, YELLOW, q / 5) : lerp(YELLOW, GREEN, (q - 5) / 4);
        return `${r}, ${g}, ${b}`;
    }

    function priceQualityColor(quality) {
        const rgb = priceQualityRgb(quality);
        return rgb ? `rgb(${rgb})` : null;
    }

    // 0-9 score -> 0-4 meter level. 0-1 / 2-3 / 4-5 / 6-7 / 8-9.
    function priceQualityLevel(quality) {
        if (typeof quality !== 'number' || Number.isNaN(quality)) return null;
        const q = Math.max(0, Math.min(9, quality));
        return Math.min(4, Math.floor(q / 2));
    }

    // Monochrome 5-step signal-strength meter. size: undefined | 'sm'.
    function qualityMeterHtml(quality, opts) {
        const level = priceQualityLevel(quality);
        if (level === null) return '';
        const size = opts && opts.size === 'sm' ? ' data-size="sm"' : '';
        const title = `Качество цены: ${quality}/9`;
        let bars = '';
        for (let i = 0; i < 5; i++) {
            bars += `<i class="${i <= level ? 'on' : ''}"></i>`;
        }
        return `<span class="qf-quality-meter"${size} role="img" aria-label="${title}" title="${title}">${bars}</span>`;
    }

    // Small indicator for compact contexts (search dropdown, configurator table cell).
    function qualityDotHtml(quality) {
        if (isAccessible()) return qualityMeterHtml(quality, { size: 'sm' });
        const color = priceQualityColor(quality);
        if (!color) return '';
        return `<span class="inline-block w-2 h-2 rounded-full" style="background-color: ${color}" title="Качество цены: ${quality}/9"></span>`;
    }

    // Indicator for a dedicated "quality" column/cell.
    function qualityBadgeHtml(quality) {
        if (typeof quality !== 'number') return '<span class="text-gray-400">-</span>';
        if (isAccessible()) return qualityMeterHtml(quality, { size: 'sm' });
        const color = priceQualityColor(quality);
        return `<span class="font-semibold" style="color: ${color}" title="Качество цены: ${quality}/9">${quality}</span>`;
    }

    // Light row-tint background for table rows, e.g. the pricing tab. Suppressed
    // in accessible mode — the pricing tab carries its own leading meter column there.
    function qualityRowStyle(quality) {
        if (isAccessible()) return '';
        const rgb = priceQualityRgb(quality);
        return rgb ? `background-color: rgba(${rgb}, 0.10)` : '';
    }

    window.priceQualityColor = priceQualityColor;
    window.priceQualityLevel = priceQualityLevel;
    window.qualityMeterHtml = qualityMeterHtml;
    window.qualityDotHtml = qualityDotHtml;
    window.qualityBadgeHtml = qualityBadgeHtml;
    window.qualityRowStyle = qualityRowStyle;
})();