import fs from 'node:fs'
import path from 'node:path'
import { createRequire } from 'node:module'

const ROOT = process.cwd()
const SOURCE_SCHEMA = path.join(ROOT, 'prisma', 'schema.prisma')
const require = createRequire(import.meta.url)
const clientPackage = require.resolve('@prisma/client/package.json')
const GENERATED_SCHEMA = path.resolve(path.dirname(clientPackage), '..', '..', '.prisma', 'client', 'schema.prisma')

function readSchemaShape(schemaPath) {
  const source = fs.readFileSync(schemaPath, 'utf8')
  const shape = {}
  const declaration = /(?:^|\n)(model|enum)\s+(\w+)\s*\{([\s\S]*?)\n\}/g

  for (const match of source.matchAll(declaration)) {
    const [, kind, name, body] = match
    const members = []

    for (const rawLine of body.split(/\r?\n/)) {
      const line = rawLine.trim()
      if (!line || line.startsWith('//') || line.startsWith('@@')) continue
      const [memberName, memberType] = line.split(/\s+/)
      members.push(kind === 'model' ? `${memberName}:${memberType}` : memberName)
    }

    shape[`${kind}:${name}`] = members.sort()
  }

  return shape
}

if (!fs.existsSync(GENERATED_SCHEMA)) {
  throw new Error(`Prisma Client schema is missing: ${GENERATED_SCHEMA}`)
}

const sourceShape = readSchemaShape(SOURCE_SCHEMA)
const generatedShape = readSchemaShape(GENERATED_SCHEMA)

if (JSON.stringify(sourceShape) !== JSON.stringify(generatedShape)) {
  const sourceKeys = new Set(Object.keys(sourceShape))
  const generatedKeys = new Set(Object.keys(generatedShape))
  const missingDeclarations = [...sourceKeys].filter((key) => !generatedKeys.has(key))
  const staleDeclarations = [...sourceKeys].filter((key) => (
    generatedKeys.has(key)
    && JSON.stringify(sourceShape[key]) !== JSON.stringify(generatedShape[key])
  ))
  throw new Error(
    `Prisma Client does not match prisma/schema.prisma; regenerate it before building. `
      + `Missing declarations: ${missingDeclarations.join(', ') || 'none'}. `
      + `Stale declarations: ${staleDeclarations.join(', ') || 'none'}.`,
  )
}

console.log(`Prisma Client schema verified (${Object.keys(sourceShape).length} declarations)`)