/**
 * lib/appsettings.ts — Resolve the generated SmartStack app's DB connection string
 * from appsettings*.json, for skill CLIs (run via `npx tsx`, with no access to the
 * CLI's own `src/lib`). Mirrors the proven parse logic of `src/lib/appsettings.ts`.
 */
import { existsSync, readFileSync } from 'node:fs'
import { join } from 'node:path'

export interface ParsedConnection {
  server: string
  database: string
  useWindowsAuth: boolean
  user: string | null
  password: string | null
  trustServerCertificate: boolean
  raw: string
}

function readJsonSafe(filePath: string): Record<string, any> | null {
  try {
    if (!existsSync(filePath)) return null
    return JSON.parse(readFileSync(filePath, 'utf-8')) as Record<string, any>
  } catch {
    return null
  }
}

/**
 * Resolve `ConnectionStrings:DefaultConnection` from an API folder, preferring the
 * gitignored `appsettings.Local.json` (where `ss dev` writes the real credentials),
 * then `appsettings.Development.json`, then the base `appsettings.json`.
 */
export function resolveConnectionString(apiDir: string): { value: string | null; source: string | null } {
  const candidates = ['appsettings.Local.json', 'appsettings.Development.json', 'appsettings.json']
  for (const file of candidates) {
    const json = readJsonSafe(join(apiDir, file))
    const cs = json?.ConnectionStrings?.DefaultConnection
    if (typeof cs === 'string' && cs.length > 0) return { value: cs, source: file }
  }
  return { value: null, source: null }
}

/** Parse a SQL Server connection string into its components. */
export function parseConnectionString(connStr: string): ParsedConnection {
  const parts: Record<string, string> = {}
  for (const segment of connStr.split(';')) {
    const eq = segment.indexOf('=')
    if (eq < 0) continue
    const key = segment.slice(0, eq).trim().toLowerCase()
    const value = segment.slice(eq + 1).trim()
    if (key && value) parts[key] = value
  }
  const integrated = (parts['integrated security'] ?? parts['trusted_connection'] ?? '').toLowerCase()
  const trust = (parts['trustservercertificate'] ?? '').toLowerCase()
  return {
    server: parts['server'] ?? parts['data source'] ?? 'localhost',
    database: parts['database'] ?? parts['initial catalog'] ?? 'SmartStack',
    useWindowsAuth: integrated === 'true' || integrated === 'sspi' || integrated === 'yes',
    user: parts['user id'] ?? parts['uid'] ?? null,
    password: parts['password'] ?? parts['pwd'] ?? null,
    trustServerCertificate: trust === 'true' || trust === 'yes',
    raw: connStr,
  }
}