import { fileURLToPath } from 'node:url'
import { defineConfig } from 'vite'
import type { Plugin } from 'vite'
import react from '@vitejs/plugin-react'

const src = (rel: string): string => fileURLToPath(new URL(rel, import.meta.url))
const STANDALONE_ERROR = 'apps/web is not a standalone application: bare Vite cannot inject window.__DSH_BOOT__. '
  + 'Build with `pnpm run build && pnpm run build:web`, then run `dsh web` (repository checkout: `pnpm run dsh -- web`). '
  + 'For client-plugin HMR, run `pnpm run dsh -- web --dev` together with `pnpm run dev:web`.'

/** Fail before a Vite dev or preview server can expose the boot-manifest-free shell. */
function rejectStandaloneServe(): Plugin {
  return {
    name: 'dsh-reject-standalone-web-serve',
    config(_config, env) {
      if (env.command === 'serve') throw new Error(STANDALONE_ERROR)
    },
  }
}

/**
 * Vendor-chunk membership, by exact npm package name — the heavy render
 * families (math, highlight, markdown) that change only on dependency bumps.
 * Only packages workspace code imports DIRECTLY need listing: their private
 * transitive dependencies (oniguruma machinery, character tables, …) are
 * imported solely by these and rollup's chunk coloring pulls them into
 * vendor automatically. A dependency shared with index-side code falls back
 * to index — a few kB of dilution, never a correctness problem. Anything not
 * listed (react family, the vendored cordis workspace, tiny helpers like
 * anser/clsx, all workspace code) stays in the default `index` chunk, so
 * editing shell code re-hashes only index and returning clients keep the
 * cached vendor chunk.
 *
 * Boundary invariant: every member must be react-free. A package that
 * imports react/jsx-runtime must never be listed — rollup folds a module
 * shared between the entry and a manual chunk into the manual chunk, so one
 * react-importing member would drag the single shared react copy into
 * vendor. The React side of markdown/math rendering is workspace code and
 * rides index.
 */
const VENDOR_PACKAGES: ReadonlySet<string> = new Set([
  // math
  'katex',
  // syntax highlight (@shikijs/langs is handled separately below —
  // lazy grammars must not land here)
  'shiki',
  // markdown parse pipeline (micromark/mdast; the incremental React renderer
  // over it is workspace code)
  'mdast-util-from-markdown',
  'mdast-util-gfm',
  'mdast-util-math',
  'micromark-core-commonmark',
  'micromark-extension-gfm',
  'micromark-extension-math',
  'micromark-factory-space',
  'micromark-util-character',
  'micromark-util-classify-character',
  'micromark-util-sanitize-uri',
  'micromark-util-symbol',
  'micromark-util-types',
])

/**
 * Boot grammars statically imported by ui-primitives' highlight.ts
 * (`@shikijs/langs/typescript` → `dist/typescript.mjs`, etc.). They live in
 * the same package as the lazy read-card grammars, but unlike those they are
 * part of the initial load and belong in the vendor chunk; the lazy ones must
 * stay unassigned so each keeps its own on-demand chunk.
 */
const BOOT_GRAMMAR_FILES: readonly string[] = [
  'dist/typescript.mjs',
  'dist/shellscript.mjs',
  'dist/json.mjs',
]

/** Font asset extensions routed to assets/fonts/ (KaTeX's woff2/woff/ttf faces today). */
const FONT_EXTENSIONS: readonly string[] = ['.woff2', '.woff', '.ttf']

/** npm package name of a resolved module id (the segment after the LAST `node_modules/` — pnpm nests the real package under an inner node_modules). */
function npmPackageOf(id: string): string | undefined {
  const parts = id.split('/node_modules/')
  if (parts.length === 1) return undefined
  const [first, second] = parts[parts.length - 1].split('/')
  if (first.startsWith('.')) return undefined // .pnpm store segment, not a package
  if (first.startsWith('@')) return second === undefined ? undefined : `${first}/${second}`
  return first
}

export default defineConfig({
  plugins: [rejectStandaloneServe(), react()],
  build: {
    sourcemap: true,
    rollupOptions: {
      output: {
        // Output layout: the two main chunks stay at assets/ root; lazy
        // @shikijs/langs grammar chunks group under assets/langs/; fonts
        // (today all KaTeX faces referenced by vendor.css) group under
        // assets/fonts/. Sourcemaps need no arrangement: rollup writes each
        // .map next to its js and references it by bare relative filename.
        chunkFileNames(chunk): string {
          // Grammar chunks are recognized by their member modules, not the
          // facade: shared embedded-grammar chunks (e.g. html+javascript,
          // split out because php/ruby/mdx embed them) have no facade at all.
          // index and vendor are excluded by name — vendor legitimately
          // carries the three boot grammars.
          if (chunk.name === 'index' || chunk.name === 'vendor') return 'assets/[name]-[hash].js'
          const isLangChunk = chunk.moduleIds.some(id => id.includes('/node_modules/@shikijs/langs/'))
          return isLangChunk ? 'assets/langs/[name]-[hash].js' : 'assets/[name]-[hash].js'
        },
        assetFileNames(asset): string {
          const fileName = asset.names[0] ?? ''
          const isFont = FONT_EXTENSIONS.some(ext => fileName.endsWith(ext))
          return isFont ? 'assets/fonts/[name]-[hash][extname]' : 'assets/[name]-[hash][extname]'
        },
        manualChunks(id: string): string | undefined {
          const pkg = npmPackageOf(id)
          if (pkg === undefined) return undefined // workspace + vendored cordis: index
          if (pkg === '@shikijs/langs') {
            return BOOT_GRAMMAR_FILES.some(file => id.endsWith(`/${file}`)) ? 'vendor' : undefined
          }
          return VENDOR_PACKAGES.has(pkg) ? 'vendor' : undefined
        },
      },
    },
  },
  resolve: {
    // Workspace packages resolve to SOURCE: package.json exports point at lib
    // for Node/type consumers, but the browser bundle must compile src directly
    // so CSS rides vite's pipeline instead of the CSS-externalized lib bundle.
    // Only the shell's normal-package surface is aliased — plugin packages are
    // NEVER bundled here (web2 shell self-sufficiency); they arrive as runtime
    // bundles through the client module system. Order matters — subpath
    // aliases must win over bare-name prefixes.
    alias: [
      // Browserization of the vendored cordis Loader: its only node-only
      // import; the two process probes are mapped by `define` below.
      { find: /^node:module$/, replacement: src('./src/node-module-stub.ts') },
      { find: /^@deepseek-ai\/dsh-client-web$/, replacement: src('../../packages/client/web/src/boot.tsx') },
      { find: /^@deepseek-ai\/dsh-client-web-react$/, replacement: src('../../packages/client/web-react/src/index.ts') },
      { find: /^@deepseek-ai\/dsh-client-ui-slots$/, replacement: src('../../packages/client/ui-slots/src/index.ts') },
      { find: /^@deepseek-ai\/dsh-client-ui-primitives$/, replacement: src('../../packages/client/ui-primitives/src/index.ts') },
      { find: /^@deepseek-ai\/dsh-client-schema-form$/, replacement: src('../../packages/client/schema-form/src/index.ts') },
      { find: /^@deepseek-ai\/dsh-client-modules\/client$/, replacement: src('../../packages/client/modules/src/client/index.ts') },
    ],
  },
  define: {
    // vendored loader internal.ts: fromInternal() probes the Node major —
    // "0.0.0" takes neither branch, returning undefined (exactly the empty
    // internal slot the shell boot fills with the client module loader).
    'process.versions.node': '"0.0.0"',
    'process.execArgv': '[]',
    // vendored loader index.ts: envData falls to its default branch.
    'process.env.CORDIS_SHARED': 'undefined',
  },
})