import type { Integration, IntegrationContext } from "../contracts/index.ts";
import { compileCss } from "../views/css/index.ts";

/** The states the utilities know. */
export const STATES = [
	"open",
	"closed",
	"active",
	"disabled",
	"loading",
	"checked",
	"selected",
] as const;

/** The size of the grid that tracks the pointer. */
export interface TrackerOptions {
	/** Columns of the grid. */
	columns?: number;
	/** Rows of the grid. */
	rows?: number;
	/** Extra grid detail, multiplied into each axis. */
	detail?: number;
	/** Enables the CSS grid to receive pointer events. Disabled by default. */
	capture?: boolean;
	/** Stable name for a tracker mounted inside one component. */
	scope?: string;
}

/** The list of a range, used by the loops of the stylesheet. */
function range(count: number): string {
	return Array.from({ length: count }, (_, index) => index + 1).join(" ");
}

/**
 * The stylesheet of the integration.
 *
 * The mouse position is tracked by a grid of cells, the parent hack moves the
 * custom properties of the root element: every cell knows its position, the
 * `:has()` selector of the parent picks the hovered one.
 */
export function reactStylesheet(options: TrackerOptions = {}): string {
	const detail = Math.max(1, options.detail ?? 1);
	const columns = (options.columns ?? 10) * detail;
	const rows = (options.rows ?? 10) * detail;
	const states = STATES.join(" ");

	return `
$columns: ${columns};
$rows: ${rows};

@each $state in ${states} {
	.state-#{$state} {
		--muddle-state: #{$state};
	}

	[data-state="#{$state}"] {
		--muddle-state: #{$state};
	}
}

[data-state] {
	--muddle-state-opacity: 1;
	--muddle-state-visibility: visible;
}

[data-state="closed"] {
	--muddle-state-opacity: 0;
	--muddle-state-visibility: hidden;
}

[data-state="disabled"] {
	--muddle-state-opacity: 0.5;
}

[data-state="loading"] {
	--muddle-state-opacity: 0.7;
}

.state-open {
	--muddle-state-opacity: 1;
	--muddle-state-visibility: visible;
}

.state-closed {
	--muddle-state-opacity: 0;
	--muddle-state-visibility: hidden;
}

.peer:checked ~ [data-state="checked"] {
	display: block;
}

.peer:not(:checked) ~ [data-state="unchecked"] {
	display: none;
}

`;
}

/** CSS for one explicitly mounted tracker. */
export function mouseTrackerCss(options: TrackerOptions = {}): string {
	const detail = Math.max(1, options.detail ?? 1);
	const columns = (options.columns ?? 10) * detail;
	const rows = (options.rows ?? 10) * detail;
	const scope = options.scope ?? "default";
	const selector = `[data-muddle-tracker="${scope}"]`;
	const rules = Array.from({ length: columns * rows }, (_, index) => {
		const x = Math.floor(index / rows) + 1;
		const y = (index % rows) + 1;
		return `${selector}:has(.mouse-tracker__cell:nth-child(${index + 1}):hover) { --muddle-mouse-x: ${x / columns * 100}%; --muddle-mouse-y: ${y / rows * 100}%; }`;
	});
	return `${selector} { position: relative; --muddle-mouse-x: 50%; --muddle-mouse-y: 50%; }\n${selector} > .mouse-tracker { position: absolute; inset: 0; display: grid; grid-template-columns: repeat(${columns}, 1fr); grid-template-rows: repeat(${rows}, 1fr); pointer-events: none; }\n${selector}[data-muddle-capture="true"] > .mouse-tracker .mouse-tracker__cell { pointer-events: auto; }\n${rules.join("\n")}`;
}

/** The compiled stylesheet of the integration. */
export function reactCss(options: TrackerOptions = {}): string {
	return compileCss(reactStylesheet(options));
}

/** The markup of the grid that tracks the pointer. */
export function mouseTrackerMarkup(options: TrackerOptions = {}): string {
	const detail = Math.max(1, options.detail ?? 1);
	const columns = (options.columns ?? 10) * detail;
	const rows = (options.rows ?? 10) * detail;
	const cells = Array.from(
		{ length: columns * rows },
		() => '<div class="mouse-tracker__cell"></div>',
	).join("");
	const scope = options.scope ?? "default";
	return `<div data-muddle-tracker="${scope}" data-muddle-capture="${options.capture === true}"><div class="mouse-tracker" aria-hidden="true">${cells}</div></div>`;
}

/** The markup of a checkbox, the label is the control. */
export function checkboxMarkup(options: {
	name: string;
	label: string;
	value?: string;
	checked?: boolean;
	disabled?: boolean;
	class?: string;
}): string {
	const attributes = [
		`type="checkbox"`,
		`name="${options.name}"`,
		options.value ? `value="${options.value}"` : "",
		options.checked ? "checked" : "",
		options.disabled ? "disabled" : "",
		'class="checkbox__input"',
	]
		.filter((entry) => entry.length > 0)
		.join(" ");
	return `<label class="checkbox${options.class ? ` ${options.class}` : ""}"><input ${attributes}><span class="checkbox__control" aria-hidden="true"></span><span class="checkbox__label">${options.label}</span></label>`;
}

export interface ReactIntegrationOptions extends TrackerOptions {
	/** Route the stylesheet is served at. */
	route?: string;
}

/**
 * Reactivity integration.
 */
export function reactIntegration(
	options: ReactIntegrationOptions = {},
): Integration {
	const route = options.route ?? "/_muddle/react.css";

	return {
		name: "react",
		setup(context: IntegrationContext) {
			context.loader("react", {
				name: "react",
				extensions: [".react.css"],
				load(file) {
					return {
						data: {},
						content: compileCss(`${file.source}\n${reactStylesheet(options)}`),
					};
				},
			});

			context.route("GET", route, () =>
				new Response(reactCss(options), {
					headers: {
						"content-type": "text/css; charset=utf-8",
						"cache-control": "public, max-age=3600",
					},
				}),
			);
		},
	};
}