#!/usr/bin/env bun

import fs from "fs"
import path from "path"
import { fileURLToPath } from "url"

const __filename = fileURLToPath(import.meta.url)
const __dirname = path.dirname(__filename)
const cliDir = path.resolve(__dirname, "..")
const repoRoot = path.resolve(cliDir, "../..")
const distDir = path.resolve(repoRoot, "frontend/workspace/dist")
const outFile = path.resolve(cliDir, "src/web/assets.generated.ts")

if (!fs.existsSync(distDir)) {
  throw new Error(
    `frontend/workspace/dist not found at ${distDir} — run \`cd frontend/workspace && bun run build\` first`,
  )
}

function walk(dir: string, out: string[] = []): string[] {
  for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
    const full = path.join(dir, entry.name)
    if (entry.isDirectory()) walk(full, out)
    else if (entry.isFile()) out.push(full)
  }
  return out
}

const files = walk(distDir).sort()
const outDir = path.dirname(outFile)
fs.mkdirSync(outDir, { recursive: true })

const lines: string[] = [
  "// AUTO-GENERATED by script/generate-web-assets.ts — do not edit by hand.",
  "// Regenerated by `backend/cli/script/build.ts` after every vite build of frontend/workspace.",
  "// @ts-nocheck",
  "",
]

const entries: string[] = []
files.forEach((absPath, i) => {
  const rel = path.relative(distDir, absPath).replaceAll("\\", "/")
  const ident = `_${i}`
  const importRel = path.relative(outDir, absPath).replaceAll("\\", "/")
  const importSpec = importRel.startsWith(".") ? importRel : `./${importRel}`
  lines.push(`import ${ident} from "${importSpec}" with { type: "file" }`)
  entries.push(`  "/${rel}": ${ident},`)
})

lines.push("")
lines.push('// Each value is the runtime path injected by Bun\'s `with { type: "file" }` loader.')
lines.push("// Typed loosely because tsgo doesn't model that loader's return type uniformly.")
lines.push("export const WEB_ASSETS: Record<string, string> = {")
for (const e of entries) lines.push(e.replace(",", " as unknown as string,"))
lines.push("}")
lines.push("")
lines.push('export const WEB_INDEX: string | undefined = WEB_ASSETS["/index.html"]')
lines.push("")

fs.writeFileSync(outFile, lines.join("\n"))
console.log(`generate-web-assets: wrote ${files.length} entries → ${path.relative(repoRoot, outFile)}`)