import { defineConfig } from 'unocss'
import fs from 'fs'
import path from 'path'

/**
 * Scans markdown files for VSCode icon patterns used in code blocks.
 * Icons are referenced with syntax: ~i-vscode-icons:file-type-name~
 * 
 * When built through docusaurus-plugin-slidev, uses environment variables:
 * - SLIDEV_ORIGINAL_SOURCE: Path to the original markdown file
 * - SLIDEV_ORIGINAL_SOURCE_DIR: Directory containing the source file
 * - SLIDEV_SITE_DIR: The Docusaurus site directory
 */
function scanFilesForIcons(): string[] {
    try {
        // Try multiple strategies to find markdown files
        const searchRoots: string[] = [
            process.cwd(),
            path.resolve(process.cwd(), 'slidev'),
            path.resolve(process.cwd(), '..'),
            path.resolve(process.cwd(), '.docusaurus'),
        ]
        
        // Add paths from docusaurus-plugin-slidev environment variables
        if (process.env.SLIDEV_ORIGINAL_SOURCE_DIR) {
            searchRoots.push(process.env.SLIDEV_ORIGINAL_SOURCE_DIR)
        }
        if (process.env.SLIDEV_SITE_DIR) {
            searchRoots.push(process.env.SLIDEV_SITE_DIR)
            searchRoots.push(path.resolve(process.env.SLIDEV_SITE_DIR, 'slidev'))
        }
        
        // Pattern to match icon references like ~i-vscode-icons:file-type-ansible~
        const iconPattern = /~(i-[a-zA-Z0-9-]+:[a-zA-Z0-9-]+)~/g
        
        // Set to store unique icons - include common defaults
        const icons = new Set([
            'i-vscode-icons:file-type-docker',
            'i-vscode-icons:file-type-python',
            'i-vscode-icons:file-type-typescript-official',
            'i-vscode-icons:file-type-js-official',
            'i-vscode-icons:file-type-yaml',
            'i-vscode-icons:file-type-json',
            'i-vscode-icons:file-type-markdown',
            'i-vscode-icons:file-type-vue',
            'i-vscode-icons:file-type-html',
            'i-vscode-icons:file-type-css',
            'i-vscode-icons:file-type-shell',
            'i-vscode-icons:file-type-powershell',
            'i-vscode-icons:file-type-git',
            'i-vscode-icons:file-type-ansible',
            'i-vscode-icons:file-type-terraform',
            'i-vscode-icons:file-type-kubernetes',
        ])
        
        // Read the original source file directly if available (from docusaurus-plugin-slidev)
        if (process.env.SLIDEV_ORIGINAL_SOURCE && fs.existsSync(process.env.SLIDEV_ORIGINAL_SOURCE)) {
            try {
                const content = fs.readFileSync(process.env.SLIDEV_ORIGINAL_SOURCE, 'utf-8')
                let match
                while ((match = iconPattern.exec(content)) !== null) {
                    if (match[1]) {
                        icons.add(match[1])
                    }
                }
            } catch {
                // Silently ignore read errors
            }
        }
        
        // Scan from each root
        for (const searchRoot of searchRoots) {
            try {
                if (!fs.existsSync(searchRoot)) continue
                
                // Find all markdown files, excluding node_modules but INCLUDE .docusaurus
                const slideFiles = fs.globSync('**/*.md', { 
                    cwd: searchRoot,
                    exclude: (name) => name === 'node_modules' || name === 'dist' || name === 'build'
                }).map((f: string) => path.resolve(searchRoot, f))
                
                // Scan each file for icon patterns
                slideFiles.forEach((file: string) => {
                    try {
                        const content = fs.readFileSync(file, 'utf-8')
                        let match
                        while ((match = iconPattern.exec(content)) !== null) {
                            if (match[1]) {
                                icons.add(match[1])
                            }
                        }
                    } catch {
                        // Silently ignore read errors
                    }
                })
            } catch {
                // Silently ignore scan errors
            }
        }
        
        return Array.from(icons) as string[]
    } catch {
        // Return default icon on error
        return ['i-vscode-icons:file-type-docker']
    }
}

export default defineConfig({
    safelist: [
        // Dynamically scan for icons in slide files
        // This returns an array of icon class names that should be included
        ...scanFilesForIcons()
    ],
})