import { ComponentParser } from 'sveld'
import * as svelte from 'svelte/compiler'
import fs from 'fs/promises'
import path from 'path'
import { preprocess } from '../../src/config/svelte.js'

export default function sveld() {
	return {
		name: 'vite-plugin-sveld',
		async transform(src, id) {
			if (id.endsWith('?raw&sveld')) {
				const raw = JSON.parse(src.split('export default ')[1])

				const data = await parseRaw(raw, id)

				return {
					code: `export default ${JSON.stringify(data)}`,
					map: null,
				}
			}
		},
		// This generates a `COMPONENT_API.json` with sveld in the `/_app` folder on build, which is used by the docs about components (only when built statically)
		async buildStart() {
			const output = {}

			const componentFiles = await fs.readdir(path.resolve('./src/components'))

			for (const fileName of componentFiles.filter((name) => name.endsWith('.svelte'))) {
				const filePath = path.resolve('./src/components', fileName)
				const raw = (await fs.readFile(filePath)).toString()
				output[fileName] = await parseRaw(raw, filePath)
			}

			try {
				await fs.mkdir(path.resolve('./generated'))
			} catch {
				// Do nothing, directory already exists
			}

			await fs.writeFile(path.resolve('./generated/COMPONENT_API.json'), JSON.stringify(output))
		},
	}
}

async function parseRaw(raw, filePath) {
	let { code } = await svelte.preprocess(raw, preprocess, {
		filename: filePath,
	})
	return new ComponentParser({
		verbose: false,
	}).parseSvelteComponent(code, {
		filePath,
		moduleName: filePath,
	})
}