import tailwindcss from '@tailwindcss/vite';
import { sveltekit } from '@sveltejs/kit/vite';
import { readFileSync, writeFileSync, existsSync, readdirSync, copyFileSync } from 'fs';
import { dirname, resolve } from 'path';
import { fileURLToPath } from 'url';

import { defineConfig, searchForWorkspaceRoot } from 'vite';
import devtoolsJson from 'vite-plugin-devtools-json';
import { storybookTest } from '@storybook/addon-vitest/vitest-plugin';

const __dirname = dirname(fileURLToPath(import.meta.url));

const GUIDE_FOR_FRONTEND = `
<!--
  This is a single file build of the frontend.
  It is automatically generated by the build process.
  Do not edit this file directly.
  To make changes, refer to the "Web UI" section in the README.
-->
`.trim();

/**
 * the maximum size of an embedded asset in bytes,
 * e.g. maximum size of embedded font (see node_modules/katex/dist/fonts/*.woff2)
 */
const MAX_ASSET_SIZE = 32000;

/** public/index.html minified flag */
const ENABLE_JS_MINIFICATION = true;

function llamaCppBuildPlugin() {
	return {
		name: 'llamacpp:build',
		apply: 'build' as const,
		closeBundle() {
			// Ensure the SvelteKit adapter has finished writing to ../public
			setTimeout(() => {
				try {
					const indexPath = resolve('../public/index.html');

					if (!existsSync(indexPath)) {
						return;
					}

					let content = readFileSync(indexPath, 'utf-8');

					const faviconPath = resolve('static/favicon.svg');
					if (existsSync(faviconPath)) {
						const faviconContent = readFileSync(faviconPath, 'utf-8');
						const faviconBase64 = Buffer.from(faviconContent).toString('base64');
						const faviconDataUrl = `data:image/svg+xml;base64,${faviconBase64}`;

						content = content.replace(/href="[^"]*favicon\.svg"/g, `href="${faviconDataUrl}"`);

						console.log('✓ Inlined favicon.svg as base64 data URL');
					}

					content = content.replace(/\r/g, '');
					content = GUIDE_FOR_FRONTEND + '\n' + content;
					content = content.replace(/\/_app\/immutable\/bundle\.[^"]+\.js/g, './bundle.js');
					content = content.replace(
						/\/_app\/immutable\/assets\/bundle\.[^"]+\.css/g,
						'./bundle.css'
					);

					writeFileSync(indexPath, content, 'utf-8');
					console.log('✓ Updated index.html');

					// Copy bundle.*.js -> ../public/bundle.js
					const immutableDir = resolve('../public/_app/immutable');
					const bundleDir = resolve('../public/_app/immutable/assets');
					if (existsSync(immutableDir)) {
						const jsFiles = readdirSync(immutableDir).filter((f) => f.match(/^bundle\..+\.js$/));
						if (jsFiles.length > 0) {
							copyFileSync(resolve(immutableDir, jsFiles[0]), resolve('../public/bundle.js'));
							console.log(`✓ Copied ${jsFiles[0]} -> bundle.js`);
						}
					}
					// Copy bundle.*.css -> ../public/bundle.css
					if (existsSync(bundleDir)) {
						const cssFiles = readdirSync(bundleDir).filter((f) => f.match(/^bundle\..+\.css$/));
						if (cssFiles.length > 0) {
							copyFileSync(resolve(bundleDir, cssFiles[0]), resolve('../public/bundle.css'));
							console.log(`✓ Copied ${cssFiles[0]} -> bundle.css`);
						}
					}
				} catch (error) {
					console.error('Failed to update index.html:', error);
				}
			}, 100);
		}
	};
}

export default defineConfig({
	resolve: {
		alias: {
			'katex-fonts': resolve('node_modules/katex/dist/fonts')
		}
	},
	build: {
		assetsInlineLimit: MAX_ASSET_SIZE,
		chunkSizeWarningLimit: 3072,
		minify: ENABLE_JS_MINIFICATION
	},
	css: {
		preprocessorOptions: {
			scss: {
				additionalData: `
					$use-woff2: true;
					$use-woff: false;
					$use-ttf: false;
				`
			}
		}
	},
	plugins: [tailwindcss(), sveltekit(), devtoolsJson(), llamaCppBuildPlugin()],
	test: {
		projects: [
			{
				extends: './vite.config.ts',
				test: {
					name: 'client',
					environment: 'browser',
					browser: {
						enabled: true,
						provider: 'playwright',
						instances: [{ browser: 'chromium' }]
					},
					include: ['tests/client/**/*.svelte.{test,spec}.{js,ts}'],
					setupFiles: ['./vitest-setup-client.ts']
				}
			},
			{
				extends: './vite.config.ts',
				test: {
					name: 'unit',
					environment: 'node',
					include: ['tests/unit/**/*.{test,spec}.{js,ts}']
				}
			},
			{
				extends: './vite.config.ts',
				test: {
					name: 'ui',
					environment: 'browser',
					browser: {
						enabled: true,
						provider: 'playwright',
						instances: [{ browser: 'chromium', headless: true }]
					},
					include: ['tests/stories/**/*.stories.{js,ts,svelte}'],
					setupFiles: ['./.storybook/vitest.setup.ts']
				},
				plugins: [
					storybookTest({
						storybookScript: 'pnpm run storybook --no-open'
					})
				]
			}
		]
	},

	server: {
		proxy: {
			'/v1': 'http://localhost:8080',
			'/props': 'http://localhost:8080',
			'/models': 'http://localhost:8080',
			'/cors-proxy': 'http://localhost:8080'
		},
		headers: {
			'Cross-Origin-Embedder-Policy': 'require-corp',
			'Cross-Origin-Opener-Policy': 'same-origin'
		},
		fs: {
			allow: [searchForWorkspaceRoot(process.cwd()), resolve(__dirname, 'tests')]
		}
	}
});