import type { ReactNode } from "react";
import {
	createCorrelationId,
	fail,
	type HousekeepingResult,
} from "../../../foundation/contracts";
import { HousekeepingPageShell } from "../../../foundation/page/housekeeping-page-shell";
import { HousekeepingPageState } from "../../../foundation/page/housekeeping-page-state";
import type { HousekeepingPageInput } from "../../../route-handlers";
import {
	type SystemConfigurationQueryData,
	type SystemConfigurationQueryInput,
	type SystemSettingRow,
	systemConfigurationQuery,
} from "../queries/configuration";

interface SystemConfigurationPageProps {
	readonly result?: HousekeepingResult<SystemConfigurationQueryData>;
}

function pageState(
	kind: "loading" | "empty" | "error",
	title: string,
	description: string,
) {
	return (
		<div data-housekeeping-state={kind}>
			<HousekeepingPageState
				state={kind}
				title={title}
				description={description}
			/>
		</div>
	);
}

function forbiddenState() {
	return (
		<section
			role="alert"
			data-housekeeping-state="forbidden"
			className="rounded-lg border border-[var(--admin-error)] bg-[var(--admin-surface)] p-4"
		>
			<h2 className="font-medium text-[var(--admin-text)]">Access denied</h2>
			<p className="mt-1 text-sm text-[var(--admin-text-muted)]">
				Your account cannot view system configuration.
			</p>
		</section>
	);
}

function settingList(title: string, rows: readonly SystemSettingRow[]) {
	return (
		<section className="rounded-lg border border-[var(--admin-border)] bg-[var(--admin-surface)] p-4">
			<h2 className="font-medium text-[var(--admin-text)]">{title}</h2>
			<dl className="mt-3 divide-y divide-[var(--admin-border)]">
				{rows.map((row) => (
					<div
						key={row.key}
						className="grid gap-1 py-2 text-sm md:grid-cols-[minmax(12rem,1fr)_2fr]"
					>
						<dt className="font-medium text-[var(--admin-text)]">{row.key}</dt>
						<dd className="break-words text-[var(--admin-text-muted)]">
							{row.value}
						</dd>
					</div>
				))}
			</dl>
		</section>
	);
}

function configurationContent(data: SystemConfigurationQueryData) {
	return data.kind === "settings" ? (
		settingList("Website settings", data.settings)
	) : (
		<div className="grid gap-4 xl:grid-cols-2">
			{settingList("Emulator settings", data.settings)}
			<div className="space-y-2">
				{settingList("Emulator texts", data.texts)}
				<p className="text-xs text-[var(--admin-text-muted)]">
					Showing {data.texts.length} of {data.textsTotal} text entries.
				</p>
			</div>
		</div>
	);
}

export function SystemConfigurationPage({
	result,
}: SystemConfigurationPageProps) {
	let body: ReactNode;
	if (!result) {
		body = pageState(
			"loading",
			"Loading configuration",
			"Reading CMS and emulator settings.",
		);
	} else if (!result.ok) {
		body =
			result.error.code === "FORBIDDEN"
				? forbiddenState()
				: pageState(
						"error",
						"Configuration unavailable",
						`Request ${result.correlationId} could not be completed.`,
					);
	} else {
		const data = result.data;
		const empty =
			data.kind === "settings"
				? data.settings.length === 0
				: data.settings.length === 0 && data.texts.length === 0;
		if (empty && data.partialDependencies.length === 0) {
			body = pageState(
				"empty",
				"No configuration entries",
				"The selected configuration source returned no entries.",
			);
		} else {
			body = (
				<div
					data-housekeeping-state={
						data.partialDependencies.length > 0 ? "partial" : "ready"
					}
					className="space-y-4"
				>
					{data.partialDependencies.length > 0 ? (
						<HousekeepingPageState
							state="partial"
							partialLabel="Partial data"
							title="Some configuration data is unavailable"
							description={`Unavailable: ${data.partialDependencies.join(", ")}`}
						/>
					) : null}
					{configurationContent(data)}
				</div>
			);
		}
	}

	return (
		<HousekeepingPageShell
			title="System configuration"
			description="Review CMS and emulator configuration sources."
		>
			{body}
		</HousekeepingPageShell>
	);
}

export async function renderSystemConfigurationPage(
	input: HousekeepingPageInput,
) {
	const queryInput: SystemConfigurationQueryInput | null =
		input.match.routeId === "system.configuration.settings"
			? { routeId: "system.configuration.settings" }
			: input.match.routeId === "system.configuration.emulator"
				? { routeId: "system.configuration.emulator" }
				: null;
	const result = queryInput
		? await systemConfigurationQuery.run(input.context, queryInput)
		: fail("NOT_FOUND", "errors.housekeeping.notFound", createCorrelationId());
	return <SystemConfigurationPage result={result} />;
}