import { existsSync, readFileSync } from "node:fs";
import { resolve } from "node:path";
import { parse as parseDotenv } from "dotenv";
import { defineConfig, type Plugin } from "vite";

function loadExtensionEnv(mode: string): NodeJS.ProcessEnv {
  const fileEnv: Record<string, string> = {};

  for (const fileName of [".env", ".env.local", `.env.${mode}`, `.env.${mode}.local`]) {
    const path = resolve(process.cwd(), fileName);

    if (existsSync(path)) {
      Object.assign(fileEnv, parseDotenv(readFileSync(path)));
    }
  }

  return { ...fileEnv, ...process.env };
}

function getGiteaHostPermissions(baseUrl?: string): string[] {
  const permissions = ["<all_urls>"];

  if (!baseUrl?.trim()) {
    return permissions;
  }

  try {
    const url = new URL(baseUrl);
    return Array.from(new Set([...permissions, `${url.protocol}//${url.host}/*`]));
  } catch {
    console.warn(`VITE_GITEA_BASE_URL is not a valid URL: ${baseUrl}`);
    return permissions;
  }
}

function chromeExtensionManifest(mode: string): Plugin {
  return {
    name: "chrome-extension-manifest",
    generateBundle() {
      const env = loadExtensionEnv(mode);
      const manifest = {
        manifest_version: 3,
        name: "Silma AI Aide",
        version: "0.1.0",
        description: "A Vite-powered side panel for Gitea-backed Silma AI aide workflows.",
        icons: {
          16: "icons/icon-16.png",
          32: "icons/icon-32.png",
          48: "icons/icon-48.png",
          128: "icons/icon-128.png"
        },
        action: {
          default_title: "Silma AI Aide",
          default_icon: {
            16: "icons/icon-16.png",
            32: "icons/icon-32.png",
            48: "icons/icon-48.png",
            128: "icons/icon-128.png"
          }
        },
        background: {
          service_worker: "assets/background.js",
          type: "module"
        },
        side_panel: {
          default_path: "index.html"
        },
        permissions: ["activeTab", "sidePanel", "storage", "tabs"],
        host_permissions: getGiteaHostPermissions(env.VITE_GITEA_BASE_URL)
      };

      this.emitFile({
        type: "asset",
        fileName: "manifest.json",
        source: `${JSON.stringify(manifest, null, 2)}\n`
      });
    }
  };
}

export default defineConfig(({ mode }) => ({
  plugins: [chromeExtensionManifest(mode)],
  build: {
    outDir: "dist",
    emptyOutDir: true,
    rollupOptions: {
      output: {
        entryFileNames: "assets/[name].js",
        chunkFileNames: "assets/[name]-[hash].js",
        assetFileNames: "assets/[name]-[hash][extname]"
      },
      input: {
        background: resolve(__dirname, "src/background.ts"),
        sidePanel: resolve(__dirname, "index.html")
      }
    }
  }
}));