import { existsSync } from "node:fs";
import { join } from "node:path";
import { Database } from "bun:sqlite";

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

const GMAIL_SETTINGS_BASIC_SCOPE =
  "https://www.googleapis.com/auth/gmail.settings.basic";

/**
 * Backfill the `gmail.settings.basic` scope for existing Google provider rows.
 *
 * The scope was added to PROVIDER_SEED_DATA in #25970. This migration ensures
 * existing workspace rows that were created before the seed update also include
 * the scope.
 *
 * This migration reads the current `defaultScopes` JSON array for the `google`
 * provider and appends the scope if it is not already present.
 */
export const backfillGoogleGmailSettingsScopeMigration: WorkspaceMigration = {
  id: "041-backfill-google-gmail-settings-scope",
  description:
    "Backfill gmail.settings.basic scope for existing Google provider rows",
  run(workspaceDir: string): void {
    const dbPath = join(workspaceDir, "data", "db", "assistant.db");
    if (!existsSync(dbPath)) {
      return;
    } // DB not created yet — nothing to backfill.

    let db: Database;
    try {
      db = new Database(dbPath);
    } catch {
      // Cannot open DB — nothing to backfill.
      return;
    }

    try {
      let row: { defaultScopes: string } | null;
      try {
        row =
          (db
            .query(
              `SELECT defaultScopes FROM oauth_providers WHERE provider = 'google'`,
            )
            .get() as { defaultScopes: string }) ?? null;
      } catch {
        // DB not initialized yet — nothing to backfill.
        return;
      }

      if (!row) {
        return;
      } // No google provider row — seed will create it fresh.

      let scopes: string[];
      try {
        const parsed = JSON.parse(row.defaultScopes);
        scopes = Array.isArray(parsed) ? parsed : [];
      } catch {
        scopes = [];
      }

      if (scopes.includes(GMAIL_SETTINGS_BASIC_SCOPE)) {
        return;
      } // Already present.

      scopes.push(GMAIL_SETTINGS_BASIC_SCOPE);

      db.query(
        `UPDATE oauth_providers SET defaultScopes = ?, updatedAt = ? WHERE provider = 'google'`,
      ).run(JSON.stringify(scopes), new Date().toISOString());
    } finally {
      db.close();
    }
  },
  down(_workspaceDir: string): void {
    // Forward-only: removing the scope would break Gmail settings functionality
    // for users who have already started using it.
  },
};