/**
 * Tests for CSS build script (scripts/build-css.js)
 * Tests minification logic and build output.
 */

const fs = require('fs-extra');
const path = require('path');
const { execSync } = require('child_process');

const rootDir = path.resolve(__dirname, '..');
const stylesDir = path.join(rootDir, 'src', 'styles');
const outputFile = path.join(rootDir, 'style.css');

describe('CSS Build Script', () => {
    let originalContent;

    beforeAll(async () => {
        // Save original style.css for restoration
        if (await fs.pathExists(outputFile)) {
            originalContent = await fs.readFile(outputFile, 'utf-8');
        }
    });

    afterAll(async () => {
        // Restore original style.css
        if (originalContent) {
            await fs.writeFile(outputFile, originalContent, 'utf-8');
        }
    });

    test('styles directory contains CSS files', async () => {
        const files = await fs.readdir(stylesDir);
        const cssFiles = files.filter(f => f.endsWith('.css'));
        expect(cssFiles.length).toBeGreaterThan(0);
        expect(cssFiles).toContain('_variables.css');
        expect(cssFiles).toContain('_08_themes.css');
    });

    test('build:css produces readable output with comments', () => {
        const result = execSync('node scripts/build-css.js', { cwd: rootDir, encoding: 'utf-8' });

        expect(result).toContain('Building CSS from src/styles/');

        const content = fs.readFileSync(outputFile, 'utf-8');
        // Readable build should contain section comments
        expect(content).toContain('/* ============================================ */');
        expect(content).toContain('/* _variables.css */');
    });

    test('build:css --minify produces minified output', () => {
        const result = execSync('node scripts/build-css.js --minify', { cwd: rootDir, encoding: 'utf-8' });

        expect(result).toContain('minified');
        expect(result).toContain('Minification:');

        const content = fs.readFileSync(outputFile, 'utf-8');
        // Minified build should NOT contain section comments
        expect(content).not.toContain('/* ============================================ */');
        // Should not have multiple consecutive spaces (except in strings)
        expect(content).not.toMatch(/[^\S\r\n]{2,}/);
        // Should not have newlines between rules
        const lines = content.split('\n');
        expect(lines.length).toBeLessThan(1000); // Original is ~12000 lines
    });

    test('minified output is smaller than readable output', () => {
        // Build readable
        execSync('node scripts/build-css.js', { cwd: rootDir, encoding: 'utf-8' });
        const readableStats = fs.statSync(outputFile);
        const readableSize = readableStats.size;

        // Build minified
        execSync('node scripts/build-css.js --minify', { cwd: rootDir, encoding: 'utf-8' });
        const minifiedStats = fs.statSync(outputFile);
        const minifiedSize = minifiedStats.size;

        expect(minifiedSize).toBeLessThan(readableSize);
        // Expect at least 30% reduction (comments + whitespace)
        const reduction = ((readableSize - minifiedSize) / readableSize) * 100;
        expect(reduction).toBeGreaterThan(30);

        // Restore readable version for other tests
        execSync('node scripts/build-css.js', { cwd: rootDir, encoding: 'utf-8' });
    });

    test('minified output preserves CSS custom properties', () => {
        execSync('node scripts/build-css.js --minify', { cwd: rootDir, encoding: 'utf-8' });

        const content = fs.readFileSync(outputFile, 'utf-8');
        // CSS variables should be preserved
        expect(content).toContain('--rpg-bg');
        expect(content).toContain('--rpg-accent');
        expect(content).toContain('--rpg-text');
        expect(content).toContain('--rpg-highlight');
        expect(content).toContain('--rpg-border');
        expect(content).toContain('--rpg-shadow');
    });

    test('minified output preserves data URIs', () => {
        execSync('node scripts/build-css.js --minify', { cwd: rootDir, encoding: 'utf-8' });

        const content = fs.readFileSync(outputFile, 'utf-8');
        // Fantasy theme has SVG data URI — should be preserved
        expect(content).toContain('data:image/svg+xml');
    });

    test('minified output preserves data-theme selectors', () => {
        execSync('node scripts/build-css.js --minify', { cwd: rootDir, encoding: 'utf-8' });

        const content = fs.readFileSync(outputFile, 'utf-8');
        expect(content).toContain('[data-theme="sci-fi"]');
        expect(content).toContain('[data-theme="fantasy"]');
        expect(content).toContain('[data-theme="cyberpunk"]');
    });

    test('themes.css uses grouped [data-theme] selectors (no duplication)', async () => {
        const themesContent = await fs.readFile(path.join(stylesDir, '_08_themes.css'), 'utf-8');

        // Should use [data-theme] grouped selectors instead of repeating all 3 themes
        expect(themesContent).toContain('.rpg-panel[data-theme] .rpg-tabs-nav');
        expect(themesContent).toContain('.rpg-panel[data-theme] .rpg-tab-btn');

        // Should NOT have the old pattern of listing all 3 themes for every element
        const oldPattern = /\.rpg-panel\[data-theme="sci-fi"\] \.rpg-tabs-nav,\s*\.rpg-panel\[data-theme="fantasy"\] \.rpg-tabs-nav,\s*\.rpg-panel\[data-theme="cyberpunk"\] \.rpg-tabs-nav/;
        expect(themesContent).not.toMatch(oldPattern);
    });

    test('themes.css defines extended custom properties per theme', async () => {
        const themesContent = await fs.readFile(path.join(stylesDir, '_08_themes.css'), 'utf-8');

        // Extended properties for content box
        expect(themesContent).toContain('--rpg-content-bg');
        expect(themesContent).toContain('--rpg-content-box-shadow');
        expect(themesContent).toContain('--rpg-content-border');

        // Extended properties for headers
        expect(themesContent).toContain('--rpg-header-text-shadow');
        expect(themesContent).toContain('--rpg-header-font-family');

        // Extended properties for dividers
        expect(themesContent).toContain('--rpg-divider-bg');
        expect(themesContent).toContain('--rpg-divider-content');

        // Extended properties for thoughts
        expect(themesContent).toContain('--rpg-thoughts-bg');
    });
});