import { homedir } from "node:os";
import { resolve } from "node:path";
import { configLoader } from "../../src/shared/config";
import type { WorkspaceRootEntry } from "../../src/shared/config/types";

/** A workspace root with its path resolved to an absolute path. */
export interface WorkspaceRoot {
  path: string;
  alias?: string;
}

export function resolveTilde(path: string, cwd: string): string {
  return path.startsWith("~/") || path.startsWith("~\\")
    ? resolve(homedir(), path.slice(2))
    : resolve(cwd, path);
}

/** Resolve configured root entries to absolute paths, dropping duplicates. */
export function resolveRoots(
  entries: readonly WorkspaceRootEntry[],
  cwd: string,
): WorkspaceRoot[] {
  const seen = new Set<string>();
  const roots: WorkspaceRoot[] = [];
  for (const entry of entries) {
    const path = resolveTilde(entry.path, cwd);
    if (seen.has(path)) continue;
    seen.add(path);
    roots.push({ path, ...(entry.alias ? { alias: entry.alias } : {}) });
  }
  return roots;
}

export function formatWorkspaceRoots(roots: readonly WorkspaceRoot[]): string {
  if (roots.length === 0) return "";
  const lines = roots.map(
    (r) => `- ${r.path}${r.alias ? ` (${r.alias})` : ""}`,
  );
  return `\n\n## Workspace Roots\nIn addition to the current directory, these directories are also part of your workspace:\n${lines.join("\n")}`;
}

/**
 * Persist a root to the project guardrails config
 * (.pi/extensions/guardrails.json), mirroring how path-access persists
 * "always" grants.
 */
export async function persistRoot(entry: WorkspaceRootEntry): Promise<void> {
  const raw = (configLoader.getRawConfig("local") ?? {}) as Record<
    string,
    unknown
  >;
  const workspaceRoots = (raw.workspaceRoots ?? {}) as Record<string, unknown>;
  const existing = Array.isArray(workspaceRoots.roots)
    ? workspaceRoots.roots.filter(
        (item): item is WorkspaceRootEntry =>
          typeof item === "object" &&
          item !== null &&
          typeof (item as { path?: unknown }).path === "string",
      )
    : [];

  if (existing.some((item) => item.path === entry.path)) return;

  await configLoader.save("local", {
    ...raw,
    workspaceRoots: {
      ...workspaceRoots,
      roots: [...existing, entry],
    },
  });
}