const { 
    readJSON, exists
} = require("fs-extra");
const { 
    resolve, join , dirname 
} = require("path");

const getLibDir = (appPath, libname) => {
    try {
        const componentsFile = require.resolve(
            join(libname, "components.json"),
            { paths: [appPath]});
        return dirname(componentsFile);
    } catch(e) {
        console.log(e);
    }
}

const getComponentsFilepath = libPath => 
    resolve(libPath, "components.json");

module.exports.componentsFilepath = (appPath, libname) => 
    getComponentsFilepath(getLibDir(appPath, libname));

module.exports.componentLibraryInfo = async (appPath, libname) => {

    const libDir = getLibDir(appPath, libname);
    const componentsPath = getComponentsFilepath(libDir);
    
    if(!await exists(componentsPath)) {
        const e = new Error(`could not find components definition file at ${componentsPath}`);
        e.statusCode = 404;
        throw e;
    }

    try {
        const components = await readJSON(componentsPath);
        const namespacedComponents = {_lib:components._lib};
        for(let cname in components) {
            if(cname === "_lib") continue;
            const namespacedName = `${libname}/${cname}`;
            components[cname].name = namespacedName;
            namespacedComponents[namespacedName] = components[cname];
        }
        return ({
            components: namespacedComponents,
            libDir,
            componentsPath
        });
    } catch(e) {
        const err = `could not parse JSON - ${componentsPath} : ${e.message}`;
        throw new Error(err);
    }
}