import { siteSettings } from "@/lib/services/site-settings";
import { themePaletteCss } from "@/lib/theme-css";
import {
	FONTS,
	PRESETS,
	THEME_COLOR_KEYS,
	type ThemePalette,
} from "@/lib/theme-presets";

// Injects the DB-driven CSS custom properties into :root / html.dark.
// Readable (WCAG) text colors are derived centrally in themePaletteCss.
export async function ThemeVars() {
	const g = (k: string, d: string) => siteSettings.get(k, d);
	const [
		primary,
		background,
		surface,
		dropdown,
		navbar,
		navbarText,
		text,
		textMuted,
		accent,
		success,
		warning,
		error,
		info,
		buttonColor,
		buttonText,
		buttonSecondary,
		buttonSecondaryText,
		buttonDanger,
		buttonDangerText,
		buttonOutline,
		buttonOutlineText,
		linkColor,
		linkHover,
		borderColor,
		panelBorderColor,
		gradientFrom,
		gradientTo,
		borderRadius,
		fontKey,
		h1,
		h2,
		h3,
		customCss,
		adminCanvas,
		adminSurface,
		adminText,
		adminTextMuted,
		adminBorder,
		adminSidebarBg,
	] = await Promise.all([
		g("color_primary", "#f59e0b"),
		g("color_background", "#f8fafc"),
		g("color_surface", "#ffffff"),
		g("color_dropdown", "#ffffff"),
		g("color_navbar", "#ffffff"),
		g("color_navbar_text", "#1e293b"),
		g("color_text", "#0f172a"),
		g("color_text_muted", "#64748b"),
		g("color_accent", "#10b981"),
		g("color_success", "#16a34a"),
		g("color_warning", "#eab308"),
		g("color_error", "#ef4444"),
		g("color_info", "#0ea5e9"),
		g("button_primary_color", "#f59e0b"),
		g("button_text_color", "#1e293b"),
		g("button_secondary_color", "#22c55e"),
		g("button_secondary_text_color", "#ffffff"),
		g("button_danger_color", "#ef4444"),
		g("button_danger_text_color", "#ffffff"),
		g("button_outline_color", "#eeb425"),
		g("button_outline_text_color", "#1a1a2e"),
		g("link_color", "#eeb425"),
		g("link_hover_color", "#cf9d15"),
		g("border_color", "#eeb425"),
		g("panel_border_color", "#e9b124"),
		g("gradient_from", "#f59e0b"),
		g("gradient_to", "#10b981"),
		g("border_radius", "12"),
		g("font_family", "nunito"),
		g("size_heading_h1", "30"),
		g("size_heading_h2", "22"),
		g("size_heading_h3", "18"),
		g("custom_css", ""),
		g("admin_canvas", ""),
		g("admin_surface", ""),
		g("admin_text", ""),
		g("admin_text_muted", ""),
		g("admin_border", ""),
		g("admin_sidebar_bg", ""),
	]);

	// Only hex/keyword color values are admin-controlled — sanitize defensively.
	const safe = (v: string | null, d: string) =>
		v && /^[#a-zA-Z0-9(),.\s%-]+$/.test(v) ? v : d;
	const px = (v: string | null, d: string) =>
		/^\d{1,3}$/.test(v ?? "") ? (v as string) : d;

	const lightPalette = {
		color_primary: safe(primary, "#f59e0b"),
		color_background: safe(background, "#f8fafc"),
		color_surface: safe(surface, "#ffffff"),
		color_dropdown: safe(dropdown, "#ffffff"),
		color_navbar: safe(navbar, "#ffffff"),
		color_navbar_text: safe(navbarText, "#1e293b"),
		color_text: safe(text, "#0f172a"),
		color_text_muted: safe(textMuted, "#64748b"),
		color_accent: safe(accent, "#10b981"),
		color_success: safe(success, "#16a34a"),
		color_warning: safe(warning, "#eab308"),
		color_error: safe(error, "#ef4444"),
		color_info: safe(info, "#0ea5e9"),
		button_primary_color: safe(buttonColor, "#f59e0b"),
		button_text_color: safe(buttonText, "#1e293b"),
		button_secondary_color: safe(buttonSecondary, "#22c55e"),
		button_secondary_text_color: safe(buttonSecondaryText, "#ffffff"),
		button_danger_color: safe(buttonDanger, "#ef4444"),
		button_danger_text_color: safe(buttonDangerText, "#ffffff"),
		button_outline_color: safe(buttonOutline, "#eeb425"),
		button_outline_text_color: safe(buttonOutlineText, "#1a1a2e"),
		link_color: safe(linkColor, "#eeb425"),
		link_hover_color: safe(linkHover, "#cf9d15"),
		border_color: safe(borderColor, "#eeb425"),
		panel_border_color: safe(panelBorderColor, "#e9b124"),
		gradient_from: safe(gradientFrom, "#f59e0b"),
		gradient_to: safe(gradientTo, "#10b981"),
	} satisfies ThemePalette;

	const adminOverrides = {
		...(adminCanvas ? { canvas: safe(adminCanvas, "#0b0f19") } : {}),
		...(adminSurface ? { surface: safe(adminSurface, "#151b27") } : {}),
		...(adminText ? { text: safe(adminText, "#f8fafc") } : {}),
		...(adminTextMuted ? { muted: safe(adminTextMuted, "#94a3b8") } : {}),
		...(adminBorder ? { border: safe(adminBorder, "#2a3448") } : {}),
		...(adminSidebarBg ? { sidebar: safe(adminSidebarBg, "#080c18") } : {}),
	};

	const font = FONTS[fontKey ?? "nunito"] ?? FONTS.nunito;

	const presetName =
		(await g("theme_preset", "Atom (golden)")) ?? "Atom (golden)";
	const preset = PRESETS[presetName] ?? PRESETS["Atom (golden)"];
	const darkPalette = Object.fromEntries(
		await Promise.all(
			THEME_COLOR_KEYS.map(
				async (key) =>
					[
						key,
						safe(await g(`${key}_dark`, preset.dark[key]), preset.dark[key]),
					] as const,
			),
		),
	) as ThemePalette;

	const typography = [
		`--border-radius:${px(borderRadius, "12")}px`,
		`--font-family:${font.stack}`,
		`--size-heading-h1:${px(h1, "30")}px`,
		`--size-heading-h2:${px(h2, "22")}px`,
		`--size-heading-h3:${px(h3, "18")}px`,
	].join(";");

	const lightCss = themePaletteCss(":root", lightPalette, adminOverrides);
	const darkCss = themePaletteCss("html.dark", darkPalette, adminOverrides);
	// Append typography inside :root block.
	const css = `${lightCss.slice(0, -1)}${typography};}${darkCss}`;

	const googleHref = font.google
		? `https://fonts.googleapis.com/css2?family=${font.google}&display=swap`
		: null;

		return (
			<>
				{googleHref ? <link rel="stylesheet" href={googleHref} /> : null}
				<style dangerouslySetInnerHTML={{ __html: css }} />
				{customCss?.trim() ? (
					// Staff-authored custom CSS (housekeeping → Theme). Trusted input.
					<style dangerouslySetInnerHTML={{ __html: customCss }} />
				) : null}
			</>
		);
}