import type { CoreCommandPayload } from "../core-commands.js";
import type { PublicCommandPayload } from "../host/sdk-types.js";

type HostOwnedPublicCommandPayload = Extract<
	PublicCommandPayload,
	{ kind: "setContainer" | "setDefaultContainerPolicy" }
>;

export type CoreTranslatablePublicCommandPayload = Exclude<
	PublicCommandPayload,
	HostOwnedPublicCommandPayload
>;

const unreachablePublicCommand = (command: never): never => {
	throw new Error(`Unsupported public command kind: ${String(command)}`);
};

/**
 * Translate a parsed public command into the payload accepted by core.
 *
 * Host-owned container commands intentionally return null because they are
 * handled by the host adapter rather than forwarded to core.
 */
export function toCoreCommandPayload(
	command: CoreTranslatablePublicCommandPayload,
): CoreCommandPayload;
export function toCoreCommandPayload(
	command: PublicCommandPayload,
): CoreCommandPayload | null;
export function toCoreCommandPayload(
	command: PublicCommandPayload,
): CoreCommandPayload | null {
	switch (command.kind) {
		case "open": {
			const { container: _container, ...coreCommand } = command;
			return coreCommand;
		}
		case "prefetch":
		case "prerender":
		case "identify":
		case "track":
		case "configure":
		case "init":
		case "close":
		case "reset":
		case "instanceFeedback.capture":
		case "instanceFeedback.listMine":
			return command;
		case "updateHostContext":
			return {
				kind: "hostContextUpdated",
				context: command.context,
			};
		case "emitHostSignal":
			return {
				kind: "hostSignal",
				name: command.name,
				data: command.data,
			};
		case "setContainer":
		case "setDefaultContainerPolicy":
			return null;
		default:
			return unreachablePublicCommand(command);
	}
}