// Offline SQL-test helpers. No database access or command-line entry point.
import { readFileSync } from 'node:fs'

export function readInitialization(region = 'CN') {
  const name = region === 'CN' ? '头程数据库统一增量-MySQL8.sql' : '海外区域统一增量-MySQL8.sql'
  return readFileSync(new URL(`../deploy/sql/${name}`, import.meta.url), 'utf8')
}

export function tableDefinitions(sql) {
  const result = new Map()
  let schema
  for (const match of sql.matchAll(/^USE (\w+);|^CREATE TABLE (\w+) \([\s\S]*?^\) ENGINE=[^\n]+;/gm)) {
    if (match[1]) schema = match[1]
    else {
      const key = `${schema}.${match[2]}`
      if (result.has(key)) throw new Error(`Duplicate table definition: ${key}`)
      result.set(key, match[0])
    }
  }
  return result
}

export function table(sql, schema, name) {
  const value = tableDefinitions(sql).get(`${schema}.${name}`)
  if (!value) throw new Error(`Missing table: ${schema}.${name}`)
  return value
}

function splitValues(value) {
  const items = []
  let start = 0, depth = 0, quoted = false
  for (let i = 0; i < value.length; i++) {
    const c = value[i]
    if (quoted && c === '\\') { i++; continue }
    if (c === "'") {
      if (quoted && value[i + 1] === "'") { i++; continue }
      quoted = !quoted
    }
    if (quoted) continue
    if (c === '(') depth++
    if (c === ')') depth--
    if (c === ',' && depth === 0) { items.push(value.slice(start, i).trim()); start = i + 1 }
  }
  if (quoted || depth) throw new Error('Unbalanced SQL seed value')
  items.push(value.slice(start).trim())
  return items.map(item => item === 'NULL' ? null : item.startsWith("'")
    ? item.slice(1, -1).replace(/''/g, "'").replace(/\\([\\'"nrt0])/g, (_, c) => ({ n: '\n', r: '\r', t: '\t', 0: '\0' }[c] ?? c))
    : item)
}

export function seedRows(sql, name) {
  const pattern = new RegExp(`^INSERT INTO ${name} \\(([^\\n]+?)\\) VALUES \\(([^\\n]+)\\);$`, 'gm')
  return [...sql.matchAll(pattern)].map(match => {
    const keys = match[1].split(',').map(key => key.trim())
    const values = splitValues(match[2])
    if (keys.length !== values.length) throw new Error(`Invalid seed columns: ${name}`)
    return Object.fromEntries(keys.map((key, i) => [key, values[i]]))
  })
}

export function roleAuthorities(sql, roleCode) {
  const role = seedRows(sql, 'iam_role').find(row => row.role_code === roleCode)
  if (!role) throw new Error(`Missing role: ${roleCode}`)
  const granted = new Set(seedRows(sql, 'iam_role_permission').filter(row => row.role_id === role.id).map(row => row.permission_id))
  return new Set(seedRows(sql, 'iam_permission').filter(row => granted.has(row.id)).map(row => row.permission_code))
}