import { fileURLToPath, URL } from 'node:url';

import { defineConfig, type Plugin } from 'vite';
import { crx } from '@crxjs/vite-plugin';
import { nodePolyfills } from 'vite-plugin-node-polyfills';
import manifest from './manifest.json';

/**
 * Plan 04-02 CSP hardening (RESEARCH §Q1, Option β — refined #3).
 *
 * Surgically excises the `new Function("" + I)` CSP-unsafe literal from JSZip's
 * pre-bundled `dist/jszip.min.js` after Vite has rolled it into the SW chunk.
 *
 * Context: JSZip's `package.json` `"browser"` field maps `./lib/index` →
 * `./dist/jszip.min.js`, a pre-bundled CJS distribution that ships its own
 * internal CommonJS module registry (including the `setimmediate` polyfill in
 * slot 54). The pre-bundled form bypasses BOTH:
 *   - `vite-plugin-node-polyfills` `exclude: ['setimmediate']` (which only
 *     filters `node-stdlib-browser`-aliased polyfills);
 *   - Our `resolve.alias.setimmediate` (which only intercepts bare-specifier
 *     `require("setimmediate")` calls, not jszip's internal `r("setimmediate")`
 *     against its own slot table).
 *
 * Alternative considered (Option α — force JSZip's unbundled `lib/index.js`
 * entry via `resolve.alias.jszip`): tested empirically 2026-05-21 against the
 * UAT harness; broke A30+ assertions because JSZip's async-write pipeline
 * (readable-stream-browser) was not transitively wired correctly through Vite's
 * resolver. Reverted.
 *
 * The runtime IS already CSP-safe under the current bundle: the SW chunk's
 * top-of-module `queueMicrotask`-based polyfill prelude lands BEFORE JSZip is
 * imported, so the setimmediate IIFE's `if(!s.setImmediate){...}` guard skips
 * the offending body at runtime. The `new Function` literal becomes statically
 * present but runtime-unreachable. This plugin removes the static literal so
 * the build-gate `tests/build/no-new-function-in-sw-chunk.test.ts` passes
 * AND no future static-analysis auditor (or tightened MV3 CSP) flags it.
 *
 * Replacement: `(I=new Function(""+I))` → `(I=function(){})` — a no-op IIFE.
 * Since the parent `typeof I!="function"&&` guard predicates the assignment on
 * I being a non-function, and our prelude ensures the entire IIFE body never
 * executes, the replacement is observably equivalent in our codepath.
 *
 * Why not the empty arrow `()=>{}`: keeps the same `function` keyword family
 * as the surrounding code (mangler-friendly + bytecount-parity).
 *
 * Scope: applies ONLY to chunks with `setImmediate`-pattern content (a guarded
 * check before the substring replacement avoids touching unrelated chunks).
 *
 * References:
 *   - .planning/phases/04-harden-clean-up-optional/04-RESEARCH.md §Q1
 *   - .planning/phases/04-harden-clean-up-optional/04-02-PLAN.md threat model
 *     T-04-02-01 (Elevation of Privilege — `new Function` literal)
 *   - node_modules/jszip/lib/utils.js:7 (the upstream `require("setimmediate")` site)
 *   - node_modules/setimmediate/setImmediate.js (the upstream polyfill source)
 */
function stripSetimmediateNewFunction(): Plugin {
  // Exact substring from `setimmediate` package's setImmediate.js, present
  // verbatim in JSZip's pre-bundled output. The replacement is byte-shorter
  // (no `new Function("" + I)` constructor invocation); we accept the size
  // delta in favor of pinning a unique substring for the find-and-replace.
  // If this string changes in a future JSZip / setimmediate upgrade, the
  // build-gate test catches the regression (count goes back to 1).
  const NEEDLE = '(I=new Function(""+I))';
  const REPLACEMENT = '(I=function(){})';

  return {
    name: 'plan-04-02-strip-setimmediate-new-function',
    enforce: 'post',
    generateBundle(_options, bundle) {
      for (const fileName of Object.keys(bundle)) {
        const chunk = bundle[fileName];
        if (chunk.type !== 'chunk') continue;
        if (!chunk.code.includes(NEEDLE)) continue;
        chunk.code = chunk.code.split(NEEDLE).join(REPLACEMENT);
      }
    },
  };
}

export default defineConfig({
  plugins: [
    crx({
      manifest,
      contentScripts: {
        injectCss: false,
      },
    }),
    nodePolyfills({
      include: ['buffer'],
      // Plan 04-02 CSP hardening (RESEARCH §Q1 + Plan 01-12 deferred-items flip):
      // exclude the transitive `setimmediate` polyfill that vite-plugin-node-polyfills
      // bundles alongside `buffer`. NOTE: this only filters node-stdlib-browser-aliased
      // polyfills; JSZip's direct `require("setimmediate")` in its pre-bundled
      // dist/jszip.min.js bypasses this exclusion. See stripSetimmediateNewFunction()
      // plugin below for the post-bundle excision of the JSZip-side literal.
      exclude: ['setimmediate'],
      globals: {
        Buffer: true,
        global: false,
        process: false,
      },
      protocolImports: false,
    }),
    // Plan 04-02 Wave 1 — post-bundle excision of the JSZip-internal
    // setimmediate polyfill's `new Function("" + I)` literal. See the plugin
    // definition + multi-paragraph rationale above (file top).
    stripSetimmediateNewFunction(),
  ],
  resolve: {
    alias: {
      ebml: 'ebml/lib/ebml.js',
      // Plan 04-02 CSP hardening (RESEARCH §Q1, refined): redirect the
      // upstream `setimmediate` npm package (which contains a CSP-unsafe
      // `new Function("" + I)` fallback for the never-called string-form
      // `setImmediate(string)`) to a local stub that installs a safe
      // `queueMicrotask`-based polyfill. JSZip's `require("setimmediate")`
      // at `node_modules/jszip/lib/utils.js:7` bypasses
      // vite-plugin-node-polyfills' `exclude` option, so the alias is the
      // canonical interception point. See src/shared/setimmediate-stub.ts
      // for the polyfill source + threat-mitigation rationale (T-04-02-01).
      // Pinned by tests/build/no-new-function-in-sw-chunk.test.ts (1 → 0).
      setimmediate: fileURLToPath(new URL('./src/shared/setimmediate-stub.ts', import.meta.url)),
    },
  },
  // `define` text-replaces token symbols at bundle time. We declare
  // __MOKOSH_UAT__ as `false` in the production config so the gated
  // hook-import branches in src/background/index.ts + src/offscreen/
  // recorder.ts are static dead branches that Rollup tree-shakes. The
  // test-only build (vite.test.config.ts) overrides this to `true`. We
  // chose a dedicated token rather than gating on import.meta.env.MODE
  // because vitest also uses MODE='test' by default — gating on MODE
  // would activate the hooks during unit tests and overwrite the
  // vi.fn() chrome.* mocks the existing 83-test baseline relies on.
  // Reference: https://vite.dev/config/shared-options.html#define
  define: {
    __MOKOSH_UAT__: 'false',
    // Plan 01-12 Wave 5 (RESEARCH §12 + D-09 spirit-satisfaction):
    // Defensive token reserved for any future inline smoke-mode check.
    // Currently the smoke harness lives entirely in `smoke.sh` outside
    // Vite's input set — verified by `grep -rn 'smoke\|SMOKE\|data:text/html' src/`
    // returning empty. Activated by setting the env var `VITE_DEV=1`
    // before invoking `vite` / `vite build`; defaults to `false` so the
    // gated branch (if any future plan adds one) is statically tree-
    // shaken out of production. See scripts/README.md for the wider
    // dev-script isolation invariant.
    __VITE_DEV__: JSON.stringify(process.env.VITE_DEV === '1'),
  },
  build: {
    // Plan 01-11: bump from default ES2020 to ES2022 so gated top-level
    // await (`if (__MOKOSH_UAT__) { await import(...); }` in
    // src/background/index.ts + src/offscreen/recorder.ts) compiles.
    // The extension targets MV3 (Chrome ≥88); top-level await landed in
    // Chrome 89 / Edge 89 / Firefox 89 / Safari 15 per MDN — comfortably
    // inside the MV3 compatibility envelope.
    // Reference: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Operators/await#browser_compatibility
    // Reference: https://vite.dev/config/build-options.html#build-target
    target: 'es2022',
    rollupOptions: {
      input: {
        offscreen: 'src/offscreen/index.html',
        // Plan 01-10 D-17-onboarding: welcome page bundled into both
        // production and test builds. The page is reached via
        // chrome.runtime.getURL('src/welcome/welcome.html') from the
        // SW's openWelcomeIfFirstInstall helper; it requires the
        // manifest's web_accessible_resources block to be navigable.
        welcome: 'src/welcome/welcome.html',
      },
    },
  },
});