const path = require('path');
const fs = require('fs');
const linter = require('./linter');
const prompt = require('./prompt');
const os = require('os')

const it_root_questions = [
    { question: 'Service name', name: 'name', validator: linter.regex.NAME_REGEX, error: "Name must only contain lowercase letters, numbers or '-_'!" },
    { question: 'Service description', name: 'description', validator: linter.regex.DESCRIPTION_REGEX, error: "Description must be a descriptive sentence starting with a uppercase letter and ending with a '.'!" },
    { question: 'Template', name: 'template', default: defaultTemplatePath},
    { question: 'Output', name: 'output', default: results => defaultOutputPath(results.name) },
    { question: 'Namespace', name: 'namespace' },
    { question: 'Base URL', name: 'base_url'}
];

function userTemplatePath(name) {
    let templatePath = path.join(os.homedir(), '.api', 'templates', name)
    if(fs.existsSync(templatePath)) {
        return templatePath;
    }
    return false;
}

function defaultTemplatePath() {
    return userTemplatePath('default.json') ||  path.join(__dirname, '..', 'templates', 'default.json')
}

function defaultOutputPath(name) {
    return path.join(process.cwd(), `${name}.json`)
}


function doInteractiveGeneration(args) {
    prompt.start([
        ...it_root_questions
    ], results => {
        generateTemplate(results);
    });

}

function doSilentGeneration(args) {
    let config = {};
    config.template = args.template || defaultTemplatePath();
    config.name = args.name;
    config.description = args.description;
    config.output = args.output || defaultOutputPath(args.name) 
    config.namespace = args.namespace || undefined
    config.base_url = args.base_url || undefined
    config.info = userTemplatePath('info.json') || undefined

    generateTemplate(config);
}

function generateTemplate(config) {
    console.log(`Generate Service Spec for service '${config.name}' to ${config.output}`)
    let template = require(config.template);

    template.name = config.name
    template.description = config.description
    template.namespace = config.namespace
    template.base_url = config.base_url

    if(config.info) {
        template.info = require(config.info)
    }

    let messages = linter.lint(template);
    if(messages.length) {
        console.error("Failed to generate service spec:");
        messages.forEach(message => console.log(`\t${message}`));
        process.exit(-1)
    }

    let output = JSON.stringify(template, null, '\t');
    fs.writeFileSync(config.output, output);
}


module.exports = function(args) {
    if(args.silent) {
        return doSilentGeneration(args);
    }
    return doInteractiveGeneration(args);

}