import { existsSync, readFileSync } from "node:fs";
import { homedir } from "node:os";
import { join } from "node:path";
import { claudeDesktopConfigLibraryDir, resolveConfigLibraryDir } from "./desktop-3p-paths";

export interface Desktop3pConfigLibraryOptions {
  env?: NodeJS.ProcessEnv;
  platform?: NodeJS.Platform;
  homeDir?: string;
}

/**
 * Resolve the config library from the same user-data root Claude Desktop uses. Keeping this in one
 * helper prevents the writer and dashboard status probe from agreeing on a path Desktop never reads.
 *
 * The resolution itself lives in `./desktop-3p-paths`, which ports Claude Desktop's own `GE()`
 * branch for branch — including the `-3p` suffix the app appends to its userData root. Dropping
 * that suffix points us at a directory Desktop never reads (GitHub #539).
 */
export function resolveDesktop3pConfigLibraryPath(
  options: Desktop3pConfigLibraryOptions = {},
): string {
  if (options.env === undefined && options.platform === undefined && options.homeDir === undefined) {
    return claudeDesktopConfigLibraryDir();
  }
  return resolveConfigLibraryDir({
    env: options.env ?? process.env,
    platform: options.platform ?? process.platform,
    home: options.homeDir ?? homedir(),
  });
}

export interface Desktop3pMetadataEntry {
  id: string;
  name: string;
  [key: string]: unknown;
}

export interface Desktop3pMetadata {
  appliedId?: string;
  entries: Desktop3pMetadataEntry[];
  [key: string]: unknown;
}

export function parseMetadata(path: string): Desktop3pMetadata {
  if (!existsSync(path)) return { entries: [] };
  const parsed = JSON.parse(readFileSync(path, "utf8")) as Partial<Desktop3pMetadata>;
  if (!Array.isArray(parsed.entries)) throw new Error("Claude Desktop 3P _meta.json has no entries array");
  return { ...parsed, entries: parsed.entries };
}

export const SAFE_DESKTOP_PROFILE_ID = /^[A-Za-z0-9][A-Za-z0-9_-]{0,127}$/;

export function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}

export function isOwnedDesktopEntry(entry: Desktop3pMetadataEntry | undefined): boolean {
  return entry?.name === "opencodex" || entry?.name === "opencodex-standard";
}

/** A gateway row is removable; the selected standard row must always remain. */
export function isOwnedDesktopGatewayEntry(entry: Desktop3pMetadataEntry | undefined): boolean {
  return entry?.name === "opencodex";
}

export function profilePath(libraryPath: string, id: string): string {
  if (!SAFE_DESKTOP_PROFILE_ID.test(id)) throw new Error("desktop_profile_id_unsafe");
  return join(libraryPath, `${id}.json`);
}

export const OPENCODEX_DESKTOP_PROFILE_KEYS = new Set([
  "inferenceProvider",
  "inferenceCredentialKind",
  "inferenceGatewayBaseUrl",
  "inferenceGatewayApiKey",
  "modelDiscoveryEnabled",
  "inferenceModels",
]);

export function readDesktopProfileForeignKeys(path: string): Record<string, unknown> {
  if (!existsSync(path)) return {};
  const parsed = JSON.parse(readFileSync(path, "utf8")) as unknown;
  if (!isRecord(parsed)) throw new Error("Claude Desktop 3P profile is not a JSON object");
  return Object.fromEntries(
    Object.entries(parsed).filter(([key]) => !OPENCODEX_DESKTOP_PROFILE_KEYS.has(key)),
  );
}