const fs = require('fs')
const path = require('path')

function loadJsonConfig(filePath) {
  try {
    const txt = fs.readFileSync(filePath, 'utf8')
    const obj = JSON.parse(txt)
    Object.keys(obj).forEach(k => {
      if (process.env[k] === undefined) process.env[k] = String(obj[k])
    })
    console.log('Loaded config from', filePath)
    return true
  } catch (e) {
    return false
  }
}

function loadDotEnv(filePath) {
  try {
    const txt = fs.readFileSync(filePath, 'utf8')
    const lines = txt.split(/\r?\n/)
    for (const line of lines) {
      const l = line.trim()
      if (!l || l.startsWith('#')) continue
      const idx = l.indexOf('=')
      if (idx === -1) continue
      const key = l.slice(0, idx).trim()
      let val = l.slice(idx + 1).trim()
      if ((val.startsWith('"') && val.endsWith('"')) || (val.startsWith("'") && val.endsWith("'"))) {
        val = val.slice(1, -1)
      }
      if (process.env[key] === undefined) process.env[key] = val
    }
    console.log('Loaded .env from', filePath)
    return true
  } catch (e) {
    return false
  }
}

// Precedence (higher wins because we only fill undefined keys):
// 1) real environment variables
// 2) CONFIG_FILE / CONFIG_PATH (explicit)
// 3) .env (local secrets)
// 4) config.json (repo/local config)
// 5) config.json.example (defaults)
const explicitPath = process.env.CONFIG_FILE || process.env.CONFIG_PATH
const candidates = [
  explicitPath ? path.resolve(explicitPath) : null,
  path.join(__dirname, '.env'),
  path.join(__dirname, 'config.json'),
  path.join(__dirname, 'config.json.example')
].filter(Boolean)

let loadedAny = false
for (const p of candidates) {
  if (!fs.existsSync(p)) continue
  const ok = p.endsWith('.env') ? loadDotEnv(p)
    : p.endsWith('.json') ? loadJsonConfig(p)
    : false
  if (ok) loadedAny = true
}

if (!loadedAny) {
  // no config found; silent
}

module.exports = {}