import { gettextToI18next } from 'i18next-conv'
import { GettextExtractor, JsExtractors } from 'gettext-extractor';
import { JsParser } from 'gettext-extractor/dist/js/parser';
import { IJsExtractorOptions } from 'gettext-extractor/dist/js/extractors/common';

let extractor = new GettextExtractor();

interface Options {
    pot: Partial<{
        out: string
        callee: { calleeName: string|string[], options: IJsExtractorOptions}[]
    }>
}

export default function GettextLoader(options: Partial<Options> = {}) {
    const pwd = process.cwd();
    let parser: JsParser|undefined = undefined;
    if (options.pot?.out && process.env.NODE_ENV === 'development') {
        let extractorFuncs = options.pot.callee?.map(c => JsExtractors.callExpression(c.calleeName, c.options));
        if (!extractorFuncs || extractorFuncs.length === 0) {
            extractorFuncs = [
                JsExtractors.callExpression(['t'], {
                    arguments: {
                        text: 0,
                        context: 1,
                    }
                })]
        }
        parser = extractor.createJsParser(extractorFuncs);
    }
    return {
        name: 'gettext-loader',
        async transform(source: string, id: string) {
            const poRegEx = /\.po$/;
            const jsRegEx = /\.(js|jsx|ts|tsx)$/;
            if (poRegEx.test(id)) {
                const match = source.match(/Language: (\w+)/)
                const lang = match ? match[1] : 'en';

                return {
                    code: `export default ${await gettextToI18next(lang, source)}`
                }
            } else if (jsRegEx.test(id)) {
                parser?.parseFile(id.replace(pwd, '.'))
            }
            return {};
        },
        async buildEnd() {
            if (parser && options.pot?.out) {
                extractor.savePotFile(options.pot.out)
            }
        }
    }
}