import { existsSync } from 'node:fs'
import { readFile, writeFile } from 'node:fs/promises'
import { z } from 'zod'

const JOURNAL = './drizzle/meta/_journal.json'
const OUTPUT = './src/server/db/migrations.gen.ts'
const SQL_RELATIVE_FROM_OUTPUT = '../../../drizzle'

const journalEntrySchema = z.object({
  idx: z.number(),
  tag: z.string(),
  when: z.number(),
  breakpoints: z.boolean(),
})
const journalSchema = z.object({ entries: z.array(journalEntrySchema).default([]) })

type JournalEntry = z.infer<typeof journalEntrySchema>

const readJournalEntries = async (): Promise<JournalEntry[]> => {
  if (!existsSync(JOURNAL)) {
    return []
  }
  const raw: unknown = JSON.parse(await readFile(JOURNAL, 'utf-8'))
  return journalSchema.parse(raw).entries.sort((a, b) => a.idx - b.idx)
}

const main = async () => {
  const entries = await readJournalEntries()

  const imports = entries
    .map((e) => `import sql_${e.idx} from '${SQL_RELATIVE_FROM_OUTPUT}/${e.tag}.sql' with { type: 'text' }`)
    .join('\n')

  const arrayBody = entries.length
    ? `[\n${entries.map((e) => `  { tag: '${e.tag}', sql: sql_${e.idx}, when: ${e.when}, breakpoints: ${e.breakpoints} },`).join('\n')}\n]`
    : '[]'

  const out = `// AUTO-GENERATED by \`bun run db:embed\`. Do not edit.
${imports ? `${imports}\n` : ''}
export type EmbeddedMigration = { tag: string; sql: string; when: number; breakpoints: boolean }

export const embeddedMigrations: readonly EmbeddedMigration[] = ${arrayBody}
`

  await writeFile(OUTPUT, out)
  console.log(`✓ ${OUTPUT} (${entries.length} migration${entries.length === 1 ? '' : 's'})`)
}

main().catch((err) => {
  console.error('❌', err instanceof Error ? err.message : err)
  process.exit(1)
})