/**
 * Shared HTTP helpers for the Jira / Confluence / GitLab REST API tools.
 *
 * Everything here is pure (no pi API) so it can be unit-tested directly
 * (see test/api.test.ts). URLs come from config/company.json — the single
 * source of truth — and tokens from the environment. Nothing is hardcoded.
 *
 * If a required URL/token is missing the request throws a typed ERR with a
 * clear, human message instead of guessing values.
 *
 * CONFIGURE: edit config/company.json (trackerUrl, docsUrl, gitHost) and set
 *       env vars JIRA_TOKEN / CONFLUENCE_TOKEN / GITLAB_TOKEN.
 */

/** A network/config failure carrying a message fit for the user. */
export class ApiError extends Error {
	status?: number;
	constructor(message: string, status?: number) {
		super(message);
		this.name = "ApiError";
		this.status = status;
	}
}

export interface RequestOptions {
	method?: "GET" | "POST" | "PUT" | "DELETE";
	query?: Record<string, string | number | boolean | undefined>;
	body?: unknown;
	/** Override the injectable fetch (tests). Defaults to global fetch. */
	fetchImpl?: typeof fetch;
	timeoutMs?: number;
}

/** Trim a base URL so it has no trailing slash. */
function base(url: string): string {
	return url.replace(/\/+$/, "");
}

/**
 * Resolve an effective base URL from company.json + an env override.
 * The env var wins when set (and not "TODO"); otherwise the config value
 * (if set and not "TODO") is used. Trailing slashes are trimmed. Returns ""
 * when neither is configured; callers decide whether to throw.
 */
export function resolveBaseUrl(envName: string, cfgValue: string | null | undefined): string {
	const fromCfg = cfgValue && cfgValue !== "TODO" ? cfgValue : "";
	const env = process.env[envName];
	return (env && env !== "TODO" ? env : fromCfg).replace(/\/+$/, "");
}

/** Build a URL with query params; undefined/empty values are dropped. */
export function buildUrl(
	baseUrl: string,
	path: string,
	query?: RequestOptions["query"],
): string {
	const q = Object.entries(query ?? {}).filter(([, v]) => v !== undefined && v !== "");
	const qs = q.length ? "?" + q.map(([k, v]) => `${encodeURIComponent(k)}=${encodeURIComponent(String(v))}`).join("&") : "";
	return `${base(baseUrl)}${path}${qs}`;
}

/**
 * Perform an authenticated JSON request against a corporate API.
 * `baseUrl` and `token` are resolved by the caller per service.
 */
export async function apiRequest(
	baseUrl: string,
	token: string,
	path: string,
	opts: RequestOptions = {},
): Promise<unknown> {
	const { method = "GET", query, body, timeoutMs = 15000 } = opts;
	const fetchImpl = opts.fetchImpl ?? fetch;

	const url = buildUrl(baseUrl, path, query);
	const headers: Record<string, string> = {
		Accept: "application/json",
		Authorization: `Bearer ${token}`,
	};
	if (body !== undefined) headers["Content-Type"] = "application/json";

	let res: Response;
	try {
		res = await fetchImpl(url, {
			method,
			headers,
			body: body !== undefined ? JSON.stringify(body) : undefined,
			signal: AbortSignal.timeout(timeoutMs),
		});
	} catch (err) {
		const msg = err instanceof Error ? err.message : String(err);
		throw new ApiError(`Сетевой сбой при обращении к ${baseUrl}: ${msg}`, 0);
	}

	if (!res.ok) {
		// Try to surface a short API-provided error message.
		let detail = `HTTP ${res.status}`;
		try {
			const data = (await res.json()) as Record<string, unknown>;
			const m = data?.message ?? data?.error_description ?? data?.error;
			if (typeof m === "string") detail += `: ${m}`;
		} catch {
			// non-JSON error body — keep the HTTP status only.
		}
		if (res.status === 401 || res.status === 403) {
			detail += " — проверь токен и права доступа (не логируй сам токен).";
		}
		throw new ApiError(`Запрос к ${baseUrl}${path} вернул ${detail}`, res.status);
	}

	if (res.status === 204) return null;
	return res.json().catch(() => null);
}

/** Resolve a required token from the environment, throwing a helpful error. */
export function requireToken(name: string, hint: string): string {
	const v = process.env[name];
	if (!v || v === "" || v === "TODO") {
		throw new ApiError(
			`Не задан $${name} — ${hint}. Задай его в ~/.config/pi-kit/env.sh (или в окружении) и перезапусти pi.`,
		);
	}
	return v;
}