/**
 * Sandbox image build and status support.
 *
 * The image is built on demand via /sandbox-build from a bundled Dockerfile.
 * No automatic build during install; publishing a prebuilt OCI image can be
 * added later without redesigning the extension.
 */

import path from "node:path";
import { fileURLToPath } from "node:url";
import { checkDockerAvailable, dockerCommand, imageExists } from "./docker.ts";
import { IMAGE_TAG } from "./types.ts";

/** Resolve the bundled Dockerfile directory (image/ next to this package). */
export function resolveDockerfileDir(): string {
	const thisFile = fileURLToPath(import.meta.url);
	// .../extensions/docker-sandbox/image.ts -> package root image/
	return path.resolve(path.dirname(thisFile), "..", "..", "image");
}

/** Build (or rebuild) the sandbox image from the bundled Dockerfile. */
export async function buildSandboxImage(
	options: { tag?: string; signal?: AbortSignal; onStatus?: (line: string) => void },
): Promise<{ tag: string }> {
	const tag = options.tag ?? IMAGE_TAG;
	const dockerfileDir = resolveDockerfileDir();
	const args = ["build", "-t", tag, dockerfileDir];
	await dockerCommand(args, { signal: options.signal, timeoutMs: 600_000 });
	options.onStatus?.(`Built ${tag}`);
	return { tag };
}

/** Full status report for /sandbox-status. */
export interface SandboxStatus {
	cliAvailable: boolean;
	daemonAvailable: boolean;
	dockerVersion?: string;
	imageExists: boolean;
	imageTag: string;
	ready: boolean;
}

/** Produce a status report and a remediation message when not ready. */
export async function getSandboxStatus(): Promise<SandboxStatus> {
	const docker = await checkDockerAvailable();
	const image = docker.daemon ? await imageExists(IMAGE_TAG) : false;
	const ready = docker.cli && docker.daemon && image;
	return {
		cliAvailable: docker.cli,
		daemonAvailable: docker.daemon,
		dockerVersion: docker.version,
		imageExists: image,
		imageTag: IMAGE_TAG,
		ready,
	};
}

/** Build a human-readable status block for /sandbox-status. */
export function formatStatus(status: SandboxStatus): string {
	const lines: string[] = [];
	lines.push(`Docker CLI: ${status.cliAvailable ? "OK" : "MISSING"}`);
	lines.push(`Docker daemon: ${status.daemonAvailable ? "OK" : "NOT REACHABLE"}`);
	if (status.dockerVersion) lines.push(`Docker server version: ${status.dockerVersion}`);
	lines.push(`Sandbox image (${status.imageTag}): ${status.imageExists ? "present" : "missing"}`);

	if (!status.ready) {
		lines.push("");
		lines.push("Not ready. To fix:");
		if (!status.cliAvailable) {
			lines.push("  - Install Docker CLI and make sure `docker` is on PATH.");
		}
		if (status.cliAvailable && !status.daemonAvailable) {
			lines.push("  - Start the Docker daemon (Docker Desktop / dockerd) and check permissions.");
		}
		if (status.daemonAvailable && !status.imageExists) {
			lines.push(`  - Run /sandbox-build to build the ${status.imageTag} image.`);
		}
	}
	return lines.join("\n");
}