import { defineConfig } from 'vite'
import react from '@vitejs/plugin-react'
import tailwindcss from '@tailwindcss/vite'
import path from 'path'
import fs from 'fs'

// `hgui` symlinks a worktree's node_modules to the main checkout. Vite realpaths
// those before enforcing server.fs.allow, so codicon/font assets resolve outside
// the worktree root and 404. Whitelist the real node_modules locations.
const real = (p: string): string | null => {
  try {
    return fs.realpathSync(p)
  } catch {
    return null
  }
}

const fsAllow = [
  ...new Set(
    [
      path.resolve(__dirname, '../..'),
      real(path.resolve(__dirname, 'node_modules')),
      real(path.resolve(__dirname, '../../node_modules'))
    ].filter((p): p is string => p !== null)
  )
]

// The dev-only render/state churn counters (src/debug) must be imported
// STATICALLY above react-dom — react-dom captures the devtools hook at module
// init, so a dynamic import lands too late and observes zero commits. A static
// side-effect import can't be tree-shaken, so instead the whole graph is
// aliased out of any non-dev build. `command === 'serve'` covers `vite dev`;
// the perf harness opts a production build back in with VITE_PERF_PROBE=1.
const debugEntry = (command: string, env: Record<string, string>) =>
  command === 'serve' || env.VITE_PERF_PROBE === '1'
    ? path.resolve(__dirname, './src/debug/dev-only.ts')
    : path.resolve(__dirname, './src/debug/dev-only.noop.ts')

export default defineConfig(({ command }) => ({
  base: './',
  plugins: [react(), tailwindcss()],
  css: {
    // Pin an explicit (empty) PostCSS config. Tailwind is handled entirely by
    // `@tailwindcss/vite`, so the renderer needs no PostCSS plugins — and
    // without this, Vite's `postcss-load-config` walks UP the filesystem
    // looking for a stray `postcss.config.*` / `tailwind.config.*`. The desktop
    // build runs from inside the user's home tree (e.g.
    // `C:\Users\<name>\AppData\Local\hermes\hermes-agent\apps\desktop`), so an
    // unrelated Tailwind v3 config higher up the tree gets picked up and
    // reprocesses our v4 stylesheet, failing the build with
    // "`@layer base` is used but no matching `@tailwind base` directive is
    // present." Pinning the config makes the build hermetic.
    postcss: { plugins: [] }
  },
  build: {
    // The renderer intentionally ships FEW chunks (not one, not thousands):
    //   · `codeSplitting: false` (the old setup) inlines every `lazy()` /
    //     dynamic import into the entry, so heavyweight lazy-only deps
    //     (mermaid, shiki grammars, katex) are parsed + evaluated on every
    //     cold start even though nothing rendered them. By the time the
    //     bundle hit ~28 MB that eval was ~1s of launch on an M-series.
    //   · Default splitting emits a chunk per shiki grammar/theme — thousands
    //     of files, which electron-builder OOMs scanning (#38888).
    // `advancedChunks` is the middle ground: heavyweight libraries merge into
    // a handful of named vendor chunks loaded on first use, app-level dynamic
    // imports stay lazy, and the file count stays in the tens.
    chunkSizeWarningLimit: 25000,
    rolldownOptions: {
      output: {
        advancedChunks: {
          groups: [
            // Shared foundations FIRST (first match wins): an unmatched
            // module shared by the entry and a heavy chunk gets merged INTO
            // the heavy chunk, and the entry then statically imports 19 MB of
            // shiki just to reach react/hast utils — putting the heavy chunk
            // right back on the boot path.
            { name: 'vendor-react', test: /node_modules[\\/](react|react-dom|scheduler)[\\/]/ },
            {
              name: 'vendor-md',
              test: /node_modules[\\/](property-information|hast-util-[^\\/]+|mdast-util-[^\\/]+|micromark[^\\/]*|unist-util-[^\\/]+|vfile[^\\/]*|unified|stringify-entities|space-separated-tokens|comma-separated-tokens|zwitch|html-void-elements|devlop|style-to-js|style-to-object|clsx)[\\/]/
            },
            // Shared utility packages the entry ALSO uses — kept out of the
            // heavy groups for the same boot-path reason.
            {
              name: 'vendor-util',
              test: /node_modules[\\/](lodash-es|es-toolkit|uuid|dayjs|d3-array|d3-color|d3-force|d3-interpolate|d3-time[^\\/]*|dompurify|stylis)[\\/]/
            },
            // One chunk per heavyweight, lazy-only library family.
            // @streamdown/code lives WITH shiki because it statically imports
            // the full shiki bundle.
            {
              name: 'mermaid',
              test: /node_modules[\\/](mermaid|cytoscape|dagre|khroma|elkjs|d3|d3-[^\\/]+|@mermaid-js)[\\/]/
            },
            {
              name: 'shiki',
              test: /node_modules[\\/](shiki|@shikijs|react-shiki|@streamdown[\\/]code|oniguruma-to-es|oniguruma-parser|regex(-[^\\/]+)?)[\\/]/
            },
            { name: 'katex', test: /node_modules[\\/]katex[\\/]/ }
          ]
        }
      }
    }
  },
  resolve: {
    alias: {
      '@/debug/dev-only': debugEntry(command, process.env as Record<string, string>),
      '@': path.resolve(__dirname, './src'),
      '@hermes/plugin-sdk': path.resolve(__dirname, './src/sdk/index.ts'),
      '@hermes/shared/billing': path.resolve(__dirname, '../shared/src/billing-types.ts'),
      '@hermes/shared': path.resolve(__dirname, '../shared/src'),
      react: path.resolve(__dirname, '../../node_modules/react'),
      'react-dom': path.resolve(__dirname, '../../node_modules/react-dom'),
      'react/jsx-dev-runtime': path.resolve(__dirname, '../../node_modules/react/jsx-dev-runtime.js'),
      'react/jsx-runtime': path.resolve(__dirname, '../../node_modules/react/jsx-runtime.js')
    },
    dedupe: ['react', 'react-dom']
  },
  server: {
    host: '127.0.0.1',
    port: 5174,
    strictPort: true,
    fs: {
      allow: fsAllow
    }
  },
  preview: {
    host: '127.0.0.1',
    port: 4174
  }
}))