/* Core-side, non-interactive installation-default writer used only through compose exec.
 * It accepts no credentials and writes the same SETTINGS_FILE consumed by session creation. */
import { readFileSync } from "node:fs";
import { loadConfig } from "../config.js";
import {
  captureSettingsSnapshot,
  loadSettings,
  restoreSettingsSnapshot,
  saveSettings,
  type Settings,
  type SettingsSnapshot,
} from "./settings-store.js";

const choice = /^[A-Za-z0-9][A-Za-z0-9._/-]{0,127}$/;

function value(args: string[], flag: string): string {
  const at = args.indexOf(flag);
  if (at < 0 || at + 1 >= args.length || args.filter((part) => part === flag).length !== 1) {
    throw new Error(`missing ${flag}`);
  }
  return args[at + 1];
}

try {
  const args = process.argv.slice(2);
  const cfg = loadConfig(process.env);
  if (args.length === 1 && args[0] === "--snapshot") {
    process.stdout.write(`${JSON.stringify(captureSettingsSnapshot(cfg))}\n`);
  } else if (args.length === 1 && args[0] === "--restore") {
    const parsed = JSON.parse(readFileSync(0, "utf8")) as Partial<SettingsSnapshot>;
    if (Object.keys(parsed).some((key) => key !== "exists" && key !== "rawBase64")) {
      throw new Error("invalid settings snapshot");
    }
    restoreSettingsSnapshot(cfg, parsed as SettingsSnapshot);
  } else {
    if (args.length !== 6) throw new Error("only provider, model, and thinking may be configured");
    const provider = value(args, "--provider");
    const model = value(args, "--model");
    const thinking = value(args, "--thinking");
    if (!choice.test(provider) || !choice.test(model)) throw new Error("invalid provider or model");
    if (!["low", "medium", "high"].includes(thinking)) throw new Error("invalid thinking level");
    const next: Settings = { ...loadSettings(cfg), provider, model, thinking };
    saveSettings(cfg, next);
  }
} catch (error) {
  process.stderr.write(`settings-cli: ${error instanceof Error ? error.message : "invalid configuration"}\n`);
  process.exitCode = 2;
}