import { readFile, writeFile } from 'fs/promises'

import { glob } from 'glob'

import path from 'path'

import { fileExists } from './fileExists.js'

function handleTsExamples(content: string): string {

//regex link: https://regexr.com/8f0bu

const ExampleBlockRegex = /```[tj]s file=['"]\.?\/?(\w*)\.(\w*)['"]\s*\n```/g

//the first capture group is the example file name without the extension or path, the second is the extension

const replacementString = `\nimport $1 from "./$1.$2?raw"\n\n<LiveExample src={$1} />`

return content.replace(ExampleBlockRegex, replacementString)

}

async function handleHTMLExamples(

content: string,

fileDir: string,

): Promise<string> {

const htmlCodeFenceRegex = /```html\n([\s\S]*?)\n```/g

const matches = Array.from(content.matchAll(htmlCodeFenceRegex))

const replacements = await Promise.all(

matches.map(async (match, index) => {

const htmlContent = match[1]

const exampleName = `Example${index + 1}`

const htmlFilePath = path.join(fileDir, `${exampleName}.html`)

await writeFile(htmlFilePath, htmlContent)

return {

original: match[0],

replacement: `\nimport ${exampleName} from './${exampleName}.html?raw'\n\n<LiveExample html={${exampleName}} />`,

}

}),

)

return replacements.reduce(

(result, { original, replacement }) =>

result.replace(original, replacement),

content,

)

}

function removeNoLiveTags(content: string): string {

return content.replace(/```no[lL]ive/g, '```')

}

function removeExistingImports(content: string): string {

// Remove imports that are absolute and not CSS

const importRegex = /^import {?[\w\s,\n]*}? from ['"](?!\.\.?\/)(?!.*\.css['"])[^'"]*['"];?\n/gm

return content.replace(importRegex, '')

}

function convertCommentsToMDX(content: string): string {

return content.replace(

/<!--([\s\S]*?)-->/g,

(_, comment) => `{/*${comment}*/}`,

)

}

async function processFile(file: string): Promise<void> {

const exists = await fileExists(file)

// if the file is already an mdx file or doesn't exist we don't need to do anything

if (file.endsWith('.mdx') || !exists) {

return

}

const fileContent = await readFile(file, 'utf-8')

const fileDir = path.dirname(file)

const transformations = [

removeNoLiveTags,

removeExistingImports,

(content: string) => handleHTMLExamples(content, fileDir),

handleTsExamples,

convertCommentsToMDX,

]

const processedContent = await transformations.reduce(

async (contentPromise, transform) => {

const content = await contentPromise

return transform(content)

},

Promise.resolve(fileContent),

)

await writeFile(file + 'x', processedContent)

}

export async function convertToMDX(globPath: string): Promise<void> {

const files = await glob(globPath)

await Promise.all(files.map(processFile))

}