import { execSync } from "node:child_process";
import { mkdtempSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import type { PayloadEvent } from "../external.ts";
import { checkoutPrBranch } from "../mcp/checkout.ts";
import type { ToolState } from "../mcp/server.ts";
import { log } from "./cli.ts";
import type { OctokitWithPlugins } from "./github.ts";
import { isInsideDocker } from "./globals.ts";
import { $ } from "./shell.ts";

export interface SetupOptions {
  tempDir: string;
}

/**
 * Create a shared temp directory for the action
 */
export function createTempDirectory(): string {
  const sharedTempDir = mkdtempSync(join(tmpdir(), "pullfrog-"));
  process.env.PULLFROG_TEMP_DIR = sharedTempDir;
  log.info(`» created temp dir at ${sharedTempDir}`);
  return sharedTempDir;
}

/**
 * Setup the test repository for running actions
 */
export function setupTestRepo(options: SetupOptions): void {
  const tempDir = options.tempDir;
  const repo = process.env.GITHUB_REPOSITORY;
  if (!repo) throw new Error("GITHUB_REPOSITORY is required");
  log.info(`» cloning ${repo} into ${tempDir}...`);

  // use https with token in ci or when running inside docker
  if (process.env.CI || isInsideDocker) {
    const token = process.env.GITHUB_TOKEN ?? process.env.GH_TOKEN;
    if (!token) {
      throw new Error("GITHUB_TOKEN or GH_TOKEN is required for https clone in ci or docker");
    }
    $("git", ["clone", `https://x-access-token:${token}@github.com/${repo}.git`, tempDir]);
  } else {
    $("git", ["clone", `git@github.com:${repo}.git`, tempDir]);
  }
}

export interface GitContext {
  gitToken: string;
  owner: string;
  name: string;
  octokit: OctokitWithPlugins;
  toolState: ToolState;
  // restricted bash mode: disables git hooks to prevent token exfiltration
  restricted: boolean;
  postCheckoutScript: string | null;
}

export interface SetupGitParams extends GitContext {
  event: PayloadEvent;
}

/**
 * setup git configuration and authentication for the repository.
 * - configures git identity (user.email, user.name)
 * - sets up authentication via gitToken (minimal contents:write)
 * - for PR events, checks out the PR branch using shared helper
 *
 * gitToken is a minimal-permission token (contents:write only) used for git operations.
 * it is assumed to be potentially exfiltratable, so it has limited scope.
 */
export async function setupGit(params: SetupGitParams): Promise<void> {
  const repoDir = process.cwd();

  // 1. configure git identity
  log.info("» setting up git configuration...");
  try {
    // check current config - only set defaults if not configured or using generic bot
    let currentEmail = "";
    try {
      currentEmail = execSync("git config user.email", {
        cwd: repoDir,
        stdio: "pipe",
        encoding: "utf-8",
      }).trim();
    } catch {
      // not configured
    }

    const shouldSetDefaults =
      !currentEmail || currentEmail === "github-actions[bot]@users.noreply.github.com";

    if (shouldSetDefaults) {
      execSync('git config --local user.email "226033991+pullfrog[bot]@users.noreply.github.com"', {
        cwd: repoDir,
        stdio: "pipe",
      });
      execSync('git config --local user.name "pullfrog[bot]"', {
        cwd: repoDir,
        stdio: "pipe",
      });
      log.debug("» git user configured (using defaults)");
    } else {
      log.debug(`» git user already configured (${currentEmail}), skipping`);
    }

    // disable git hooks for predictability - prevents pre-commit hooks
    // from blocking commits or causing unexpected side effects
    execSync("git config --local core.hooksPath /dev/null", {
      cwd: repoDir,
      stdio: "pipe",
    });
    log.debug("» git hooks disabled");
  } catch (error) {
    // If git config fails, log warning but don't fail the action
    // This can happen if we're not in a git repo or git isn't available
    log.warning(
      `Failed to set git config: ${error instanceof Error ? error.message : String(error)}`
    );
  }

  // 2. setup authentication
  log.info("» setting up git authentication...");

  // remove existing git auth headers that actions/checkout might have set
  try {
    execSync("git config --local --unset-all http.https://github.com/.extraheader", {
      cwd: repoDir,
      stdio: "pipe",
    });
    log.info("» removed existing authentication headers");
  } catch {
    log.debug("» no existing authentication headers to remove");
  }

  // SECURITY: set origin URL without token - auth is injected via GIT_CONFIG_PARAMETERS
  // in $git() calls. this prevents token leakage to git hooks and subprocesses.
  const originUrl = `https://github.com/${params.owner}/${params.name}.git`;
  $("git", ["remote", "set-url", "origin", originUrl], { cwd: repoDir });

  // initialize pushUrl to base repo - may be updated by checkout_pr for fork PRs
  params.toolState.pushUrl = originUrl;

  // disable credential helpers to prevent prompts and ensure clean auth state
  $("git", ["config", "--local", "credential.helper", ""], { cwd: repoDir });

  // non-PR events: stay on default branch
  if (params.event.is_pr !== true || !params.event.issue_number) {
    log.info("» git authentication configured");
    return;
  }

  // PR event: checkout PR branch using shared helper
  const prNumber = params.event.issue_number;

  // use shared checkout helper (handles fork remotes, push config, post-checkout hook)
  // this updates toolState.pushUrl for fork PRs and sets toolState.issueNumber
  await checkoutPrBranch(prNumber, params);
}