const _ = require("lodash");

const prettier = require("prettier");

const { config } = require("./config");

const ts = require("typescript");

class LanguageServiceHost {

constructor(fileName, content) {

const tsconfig = ts.findConfigFile(fileName, ts.sys.fileExists);

Object.assign(this, {

fileName,

content,

compilerOptions: tsconfig

? ts.convertCompilerOptionsFromJson(

ts.readConfigFile(tsconfig, ts.sys.readFile).config.compilerOptions,

).options

: ts.getDefaultCompilerOptions(),

});

}

getNewLine() {

return "\n";

}

getScriptFileNames() {

return [this.fileName];

}

getCompilationSettings() {

return this.compilerOptions;

}

getDefaultLibFileName() {

return ts.getDefaultLibFileName(this.getCompilationSettings());

}

getCurrentDirectory() {

return process.cwd();

}

getScriptVersion() {

return ts.version;

}

getScriptSnapshot() {

return ts.ScriptSnapshot.fromString(this.content);

}

}

const removeUnusedImports = (content) => {

const tempFileName = "file.ts";

const host = new LanguageServiceHost(tempFileName, content);

const languageService = ts.createLanguageService(host);

const fileTextChanges = languageService.organizeImports(

{ type: "file", fileName: tempFileName },

{ newLineCharacter: ts.sys.newLine },

)[0];

if (fileTextChanges && fileTextChanges.textChanges.length) {

return _.reduceRight(

fileTextChanges.textChanges,

(content, { span, newText }) =>

`${content.slice(0, span.start)}${newText}${content.slice(span.start + span.length)}`,

content,

);

}

return content;

};

const prettierFormat = (content) => {

return prettier.format(content, config.prettierOptions);

};

const formatters = [removeUnusedImports, prettierFormat];

module.exports = (content) =>

formatters.reduce((fixedContent, formatter) => formatter(fixedContent), content);