// NEVER convert to top-level imports - breaks browser/Vite builds (web-ui)
let _existsSync: typeof import("node:fs").existsSync | null = null;
let _homedir: typeof import("node:os").homedir | null = null;
let _join: typeof import("node:path").join | null = null;

type DynamicImport = (specifier: string) => Promise<unknown>;

const dynamicImport: DynamicImport = (specifier) => import(specifier);
const NODE_FS_SPECIFIER = "node:" + "fs";
const NODE_OS_SPECIFIER = "node:" + "os";
const NODE_PATH_SPECIFIER = "node:" + "path";

// Eagerly load in Node.js/Bun environment only
if (
  typeof process !== "undefined" &&
  (process.versions?.node || process.versions?.bun)
) {
  dynamicImport(NODE_FS_SPECIFIER).then((m) => {
    _existsSync = (m as typeof import("node:fs")).existsSync;
  });
  dynamicImport(NODE_OS_SPECIFIER).then((m) => {
    _homedir = (m as typeof import("node:os")).homedir;
  });
  dynamicImport(NODE_PATH_SPECIFIER).then((m) => {
    _join = (m as typeof import("node:path")).join;
  });
}

import type { KnownProvider } from "./types.js";

let cachedVertexAdcCredentialsExists: boolean | null = null;

function hasVertexAdcCredentials(): boolean {
  if (cachedVertexAdcCredentialsExists === null) {
    // If node modules haven't loaded yet (async import race at startup),
    // return false WITHOUT caching so the next call retries once they're ready.
    // Only cache false permanently in a browser environment where fs is never available.
    if (!_existsSync || !_homedir || !_join) {
      const isNode =
        typeof process !== "undefined" &&
        (process.versions?.node || process.versions?.bun);
      if (!isNode) {
        // Definitively in a browser — safe to cache false permanently
        cachedVertexAdcCredentialsExists = false;
      }
      return false;
    }

    // Check GOOGLE_APPLICATION_CREDENTIALS env var first (standard way)
    const gacPath = process.env.GOOGLE_APPLICATION_CREDENTIALS;
    if (gacPath) {
      cachedVertexAdcCredentialsExists = _existsSync(gacPath);
    } else {
      // Fall back to default ADC path (lazy evaluation)
      cachedVertexAdcCredentialsExists = _existsSync(
        _join(
          _homedir(),
          ".config",
          "gcloud",
          "application_default_credentials.json",
        ),
      );
    }
  }
  return cachedVertexAdcCredentialsExists;
}

/**
 * Get API key for provider from known environment variables, e.g. OPENAI_API_KEY.
 *
 * Will not return API keys for providers that require OAuth tokens.
 */
export function getEnvApiKey(provider: KnownProvider): string | undefined;
export function getEnvApiKey(provider: string): string | undefined;
export function getEnvApiKey(provider: any): string | undefined {
  // Fall back to environment variables
  if (provider === "github-copilot") {
    return (
      process.env.COPILOT_GITHUB_TOKEN ||
      process.env.GH_TOKEN ||
      process.env.GITHUB_TOKEN
    );
  }

  // ANTHROPIC_OAUTH_TOKEN takes precedence over ANTHROPIC_API_KEY
  if (provider === "anthropic") {
    return process.env.ANTHROPIC_OAUTH_TOKEN || process.env.ANTHROPIC_API_KEY;
  }

  // Vertex AI uses Application Default Credentials, not API keys.
  // Auth is configured via `gcloud auth application-default login`.
  if (provider === "google-vertex") {
    const hasCredentials = hasVertexAdcCredentials();
    const hasProject = !!(
      process.env.GOOGLE_CLOUD_PROJECT || process.env.GCLOUD_PROJECT
    );
    const hasLocation = !!process.env.GOOGLE_CLOUD_LOCATION;

    if (hasCredentials && hasProject && hasLocation) {
      return "<authenticated>";
    }
  }

  if (provider === "amazon-bedrock") {
    // Amazon Bedrock supports multiple credential sources:
    // 1. AWS_PROFILE - named profile from ~/.aws/credentials
    // 2. AWS_ACCESS_KEY_ID + AWS_SECRET_ACCESS_KEY - standard IAM keys
    // 3. AWS_BEARER_TOKEN_BEDROCK - Bedrock API keys (bearer token)
    // 4. AWS_CONTAINER_CREDENTIALS_RELATIVE_URI - ECS task roles
    // 5. AWS_CONTAINER_CREDENTIALS_FULL_URI - ECS task roles (full URI)
    // 6. AWS_WEB_IDENTITY_TOKEN_FILE - IRSA (IAM Roles for Service Accounts)
    if (
      process.env.AWS_PROFILE ||
      (process.env.AWS_ACCESS_KEY_ID && process.env.AWS_SECRET_ACCESS_KEY) ||
      process.env.AWS_BEARER_TOKEN_BEDROCK ||
      process.env.AWS_CONTAINER_CREDENTIALS_RELATIVE_URI ||
      process.env.AWS_CONTAINER_CREDENTIALS_FULL_URI ||
      process.env.AWS_WEB_IDENTITY_TOKEN_FILE
    ) {
      return "<authenticated>";
    }
  }

  const envMap: Record<string, string> = {
    openai: "OPENAI_API_KEY",
    "azure-openai-responses": "AZURE_OPENAI_API_KEY",
    google: "GEMINI_API_KEY",
    groq: "GROQ_API_KEY",
    cerebras: "CEREBRAS_API_KEY",
    xai: "XAI_API_KEY",
    openrouter: "OPENROUTER_API_KEY",
    "vercel-ai-gateway": "AI_GATEWAY_API_KEY",
    zai: "ZAI_API_KEY",
    mistral: "MISTRAL_API_KEY",
    minimax: "MINIMAX_API_KEY",
    "minimax-cn": "MINIMAX_CN_API_KEY",
    huggingface: "HF_TOKEN",
    opencode: "OPENCODE_API_KEY",
    "opencode-go": "OPENCODE_API_KEY",
    "kimi-coding": "KIMI_API_KEY",
  };

  const envVar = envMap[provider];
  return envVar ? process.env[envVar] : undefined;
}
