/**
 * Post-import onboarding for a team migrating from GitHub.
 *
 * `POST /import/bulk` cloned repositories and inserted rows, and stopped
 * there. A team that migrated an org therefore landed on a set of bare
 * repositories with no branch protection, no labels, no CODEOWNERS, no gate
 * settings, and no evidence that any of it was worth doing. The platform's
 * entire value proposition — that it finds problems in your code — was
 * something they had to go and discover for themselves, one repo at a time.
 *
 * This runs the work for them at import time and returns a report:
 *
 *   1. bootstrapRepository()      green defaults: gates on, branch
 *                                 protection, labels, CODEOWNERS.
 *   2. runSecretAndSecurityScan() the actual proof — committed secrets and
 *                                 security findings in the code they just
 *                                 brought over.
 *
 * Everything here is best-effort by design. A migration that imported 40
 * repositories must not be reported as a failure because the scanner choked
 * on one of them, so each repo's outcome is captured independently and a
 * thrown error becomes a per-repo `error` field rather than a rejected
 * promise.
 *
 * Concurrency is bounded (DB_FANOUT_LIMIT). Scanning is IO-heavy — a tree
 * walk plus blob reads per repo — and an unbounded Promise.all over a
 * 100-repo org would open 100 concurrent walks against the same disk and
 * connection pool.
 */

import { mapWithConcurrency, DB_FANOUT_LIMIT } from "./concurrency";

/** One repository's post-import outcome. */
export interface MigrationRepoReport {
  owner: string;
  name: string;
  /** Green-default bootstrap applied (settings, protection, labels). */
  bootstrapped: boolean;
  /** Number of branch-protection rules / labels created, for the summary. */
  labelsCreated: number;
  protectionCreated: boolean;
  /** Committed secrets found in the imported code. */
  secretsFound: number;
  /** Security findings (vulnerable patterns) in the imported code. */
  securityIssues: number;
  /** Code files embedded into the semantic index. */
  filesIndexed: number;
  /** Human-readable scan detail, already scrubbed by the scanner. */
  scanDetail: string;
  /** Set when this repo's onboarding failed; the others still ran. */
  error?: string;
}

export interface MigrationReport {
  repos: MigrationRepoReport[];
  /** Totals, precomputed so the view stays markup. */
  totalRepos: number;
  totalSecrets: number;
  totalSecurityIssues: number;
  reposBootstrapped: number;
  /** Total code files embedded — what makes semantic search work at all. */
  totalFilesIndexed: number;
  reposWithFindings: number;
}

/**
 * Bootstrap and scan every freshly imported repository.
 *
 * `repos` is the subset of a bulk import that actually landed — callers pass
 * only successful imports, since there is nothing to scan otherwise.
 */
export async function runMigrationOnboarding(
  repos: Array<{ id: string; owner: string; name: string; defaultBranch?: string | null }>,
  ownerUserId: string
): Promise<MigrationReport> {
  const results = await mapWithConcurrency(
    repos,
    DB_FANOUT_LIMIT,
    async (repo): Promise<MigrationRepoReport> => {
      const base: MigrationRepoReport = {
        owner: repo.owner,
        name: repo.name,
        bootstrapped: false,
        labelsCreated: 0,
        protectionCreated: false,
        secretsFound: 0,
        securityIssues: 0,
        filesIndexed: 0,
        scanDetail: "",
      };

      const branch = repo.defaultBranch || "main";

      // 1. Green defaults. Skips the welcome issue — an imported repo has
      //    real history and real issues; a "welcome" issue on top of 400
      //    migrated ones is noise, not onboarding.
      try {
        const { bootstrapRepository } = await import("./repo-bootstrap");
        const r = await bootstrapRepository({
          repositoryId: repo.id,
          ownerUserId,
          defaultBranch: branch,
          skipWelcomeIssue: true,
        });
        base.bootstrapped = true;
        base.labelsCreated = r.labelsCreated ?? 0;
        base.protectionCreated = r.protectionCreated ?? false;
      } catch (err) {
        base.error = `bootstrap: ${err instanceof Error ? err.message : String(err)}`;
      }

      // 2. The proof. Scan the code they just brought over.
      try {
        const { runSecretAndSecurityScan } = await import("./gate");
        const scan = await runSecretAndSecurityScan(
          repo.owner,
          repo.name,
          `refs/heads/${branch}`,
          branch,
          { scanSecrets: true, scanSecurity: true }
        );
        base.secretsFound = scan.secrets.length;
        base.securityIssues = scan.securityIssues.length;
        base.scanDetail = [scan.secretResult.details, scan.securityResult.details]
          .filter(Boolean)
          .join(" · ");
      } catch (err) {
        const msg = `scan: ${err instanceof Error ? err.message : String(err)}`;
        base.error = base.error ? `${base.error}; ${msg}` : msg;
      }

      // 3. Semantic index. indexChangedFiles() is called only from the git
      //    post-receive hook, and a bulk import CLONES rather than pushes —
      //    so without this every imported repo had an empty index and
      //    semantic search, repo chat and "ask this repo" all returned
      //    nothing. Silently, because an empty index looks exactly like
      //    "no matches".
      try {
        const { indexExistingRepo } = await import("./index-existing-repo");
        const idx = await indexExistingRepo({
          repositoryId: repo.id,
          owner: repo.owner,
          repoName: repo.name,
          ref: branch,
          commitSha: branch,
        });
        base.filesIndexed = idx.indexed;
        if (idx.error) {
          base.error = base.error ? `${base.error}; index: ${idx.error}` : `index: ${idx.error}`;
        }
      } catch (err) {
        const msg = `index: ${err instanceof Error ? err.message : String(err)}`;
        base.error = base.error ? `${base.error}; ${msg}` : msg;
      }

      return base;
    }
  );

  return {
    repos: results,
    totalRepos: results.length,
    totalSecrets: results.reduce((n, r) => n + r.secretsFound, 0),
    totalSecurityIssues: results.reduce((n, r) => n + r.securityIssues, 0),
    totalFilesIndexed: results.reduce((n, r) => n + r.filesIndexed, 0),
    reposBootstrapped: results.filter((r) => r.bootstrapped).length,
    reposWithFindings: results.filter(
      (r) => r.secretsFound > 0 || r.securityIssues > 0
    ).length,
  };
}