import * as vscode from "vscode";

export const globalMap: Map<string, string> = new Map();

export async function loadMappingJson(uri: vscode.Uri): Promise<void> {
  const bytes = await vscode.workspace.fs.readFile(uri);
  const text = new TextDecoder('utf-8').decode(bytes);

  let raw: unknown;
  try {
    raw = JSON.parse(text);
  } catch (err: any) {
    throw new Error(`Failed to parse JSON: ${err?.message ?? String(err)}`);
  }

  if (typeof raw !== 'object' || raw === null || Array.isArray(raw)) {
    throw new Error(`Expected a JSON object at top level (key → value mapping).`);
  }

  const obj = raw as Record<string, unknown>;

  globalMap.clear();

  for (const [key, value] of Object.entries(obj)) {
    if (typeof value !== 'string') {
      console.warn(`⚠️ Skipping key '${key}' because its value is not a string.`);
      continue;
    }
    globalMap.set(key, value);
  }

  console.log(`✅ Loaded ${globalMap.size} valid mappings from ${uri.fsPath}`);
}