import { useState, type FormEvent } from "react";
import * as stylex from "@stylexjs/stylex";
import { ApiError } from "@/lib/api";
import InlineError from "@/lib/InlineError";
import type { Blocklist, BlocklistInput } from "@/lib/types";
import { styles as shared } from "@/ui/styles";
import { READ_ONLY_HINT } from "@/features/settings/authority";

const styles = stylex.create({
	form: {
		display: "flex",
		flexDirection: "column",
		gap: "0.75rem",
		marginTop: "1rem",
		maxWidth: "36rem",
	},
	heading: {
		fontSize: "1.125rem",
		lineHeight: "1.75rem",
		fontWeight: 500,
	},
	fieldLabel: {
		display: "block",
		fontSize: "0.875rem",
		lineHeight: "1.25rem",
		fontWeight: 500,
	},
	checkboxLabel: {
		display: "flex",
		alignItems: "center",
		gap: "0.5rem",
		fontSize: "0.875rem",
		lineHeight: "1.25rem",
		fontWeight: 500,
	},
	buttonRow: {
		display: "flex",
		alignItems: "center",
		gap: "0.5rem",
	},
	cancel: {
		fontWeight: 500,
	},
});

/**
 * Drops the rejection the page already renders inline below the form. Anything
 * else is a bug in this component and must reach the console instead of dying
 * silently in the submit handler.
 */
export function swallowMutationError(error: unknown): void {
	if (error instanceof ApiError) return;
	throw error;
}

interface BlocklistFormProps {
	initial?: Blocklist;
	busy: boolean;
	/** File authority: the server answers 403, so the submit stays down. */
	readOnly: boolean;
	error: Error | null;
	onSubmit: (input: BlocklistInput) => Promise<void>;
	onCancel?: () => void;
}

export default function BlocklistForm({ initial, busy, readOnly, error, onSubmit, onCancel }: BlocklistFormProps) {
	const [url, setUrl] = useState(initial?.url ?? "");
	const [name, setName] = useState(initial?.name ?? "");
	const [enabled, setEnabled] = useState(initial?.enabled ?? true);

	async function handleSubmit(event: FormEvent<HTMLFormElement>) {
		event.preventDefault();
		try {
			await onSubmit({ url: url.trim(), name: name.trim(), enabled });
		} catch (error) {
			swallowMutationError(error);
			return;
		}
		if (initial === undefined) {
			setUrl("");
			setName("");
			setEnabled(true);
		}
	}

	return (
		<form onSubmit={handleSubmit} {...stylex.props(styles.form)}>
			<h2 {...stylex.props(styles.heading)}>{initial === undefined ? "Add source" : `Edit ${initial.name}`}</h2>
			<div>
				<label htmlFor="blocklist-url" {...stylex.props(styles.fieldLabel)}>
					URL
				</label>
				<input
					id="blocklist-url"
					type="url"
					required
					value={url}
					onChange={(event) => setUrl(event.target.value)}
					{...stylex.props(shared.input, shared.focusRing)}
				/>
			</div>
			<div>
				<label htmlFor="blocklist-name" {...stylex.props(styles.fieldLabel)}>
					Name
				</label>
				<input
					id="blocklist-name"
					type="text"
					required
					value={name}
					onChange={(event) => setName(event.target.value)}
					{...stylex.props(shared.input, shared.focusRing)}
				/>
			</div>
			<label {...stylex.props(styles.checkboxLabel)}>
				<input
					type="checkbox"
					checked={enabled}
					onChange={(event) => setEnabled(event.target.checked)}
					{...stylex.props(shared.focusRing)}
				/>
				Enabled
			</label>
			<div {...stylex.props(styles.buttonRow)}>
				<button
					type="submit"
					disabled={busy || readOnly}
					title={readOnly ? READ_ONLY_HINT : undefined}
					{...stylex.props(shared.primaryButton, shared.focusRing)}
				>
					{initial === undefined ? "Add source" : "Save changes"}
				</button>
				{onCancel !== undefined && (
					<button
						type="button"
						onClick={onCancel}
						{...stylex.props(shared.button, styles.cancel, shared.focusRing)}
					>
						Cancel
					</button>
				)}
			</div>
			<InlineError error={error} />
		</form>
	);
}
