const fs = require("fs");
const path = require("path");

function resolveProjectRoot() {
  const envRoot = process.env.SGCLAW_PROJECT_ROOT;
  if (envRoot && fs.existsSync(envRoot)) {
    return path.resolve(envRoot);
  }

  const configPath = resolveConfigPath();
  if (configPath && fs.existsSync(configPath)) {
    return path.dirname(configPath);
  }

  return path.resolve(__dirname);
}

function resolveConfigPath() {
  const envPath = process.env.SGCLAW_CONFIG_PATH;
  if (envPath && fs.existsSync(envPath)) {
    return path.resolve(envPath);
  }

  const candidates = [
    path.resolve(__dirname, "..", "..", "sgclaw_config.json"),
    path.resolve(__dirname, "..", "sgclaw_config.json"),
    path.resolve(__dirname, "sgclaw_config.json"),
  ];

  for (const p of candidates) {
    if (fs.existsSync(p)) return p;
  }

  return null;
}

function loadConfig() {
  const configPath = resolveConfigPath();
  if (!configPath) {
    throw new Error(
      "sgclaw_config.json not found. Set SGCLAW_CONFIG_PATH or place it in the project root."
    );
  }

  const raw = fs.readFileSync(configPath, "utf-8");
  const config = JSON.parse(raw);

  const apiKey = config.apiKey || "";
  const baseUrl = config.baseUrl || "";
  const model = config.model || "";

  if (!apiKey) throw new Error("sgclaw_config.json: 'apiKey' is required");
  if (!baseUrl) throw new Error("sgclaw_config.json: 'baseUrl' is required");
  if (!model) throw new Error("sgclaw_config.json: 'model' is required");

  return {
    apiKey,
    baseUrl: normalizeBaseUrl(baseUrl),
    model,
    projectRoot: resolveProjectRoot(),
    configPath,
  };
}

function normalizeBaseUrl(url) {
  url = url.replace(/\/+$/, "");
  if (!url.endsWith("/v1")) url = url + "/v1";
  return url;
}

function getDefaults() {
  const config = loadConfig();
  const projectRoot = config.projectRoot;

  return {
    outputRoot: path.join(projectRoot, "examples", "generated_scene_platform"),
    lessonsPath: path.join(
      projectRoot,
      "docs",
      "superpowers",
      "references",
      "tq-lineloss-lessons-learned.toml"
    ),
    llmBaseUrl: config.baseUrl,
    llmModel: config.model,
  };
}

module.exports = { loadConfig, getDefaults, resolveProjectRoot, resolveConfigPath };