/**
 * @fileoverview Main CLI object.
 * @author Nicholas C. Zakas
 */

"use strict";

/*
 * The CLI object should *not* call process.exit() directly. It should only return
 * exit codes. This allows other programs to use the CLI object and still control
 * when the program exits.
 */

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

var fs = require("fs"),
    path = require("path"),

    debug = require("debug"),

    options = require("./options"),
    CLIEngine = require("./cli-engine"),
    mkdirp = require("mkdirp");

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

debug = debug("eslint:cli");

/**
 * Translates the CLI options into the options expected by the CLIEngine.
 * @param {Object} cliOptions The CLI options to translate.
 * @returns {CLIEngineOptions} The options object for the CLIEngine.
 * @private
 */
function translateOptions(cliOptions) {
    return {
        envs: cliOptions.env,
        extensions: cliOptions.ext,
        rules: cliOptions.rule,
        plugins: cliOptions.plugin,
        globals: cliOptions.global,
        ignore: cliOptions.ignore,
        ignorePath: cliOptions.ignorePath,
        ignorePattern: cliOptions.ignorePattern,
        configFile: cliOptions.config,
        rulePaths: cliOptions.rulesdir,
        reset: cliOptions.reset,
        useEslintrc: cliOptions.eslintrc
    };
}

/**
 * Outputs the results of the linting.
 * @param {CLIEngine} engine The CLIEngine to use.
 * @param {LintResult[]} results The results to print.
 * @param {string} format The name of the formatter to use or the path to the formatter.
 * @param {string} outputFile The path for the output file.
 * @returns {boolean} True if the printing succeeds, false if not.
 * @private
 */
function printResults(engine, results, format, outputFile) {
    var formatter,
        output,
        filePath;

    formatter = engine.getFormatter(format);
    if (!formatter) {
        console.error("Could not find formatter '%s'.", format);
        return false;
    }

    output = formatter(results);

    if (output) {
        if (outputFile) {
            filePath = path.resolve(process.cwd(), outputFile);

            if (fs.existsSync(filePath) && fs.statSync(filePath).isDirectory()) {
                console.error("Cannot write to output file path, it is a directory: %s", outputFile);
                return false;
            }

            try {
                mkdirp.sync(path.dirname(filePath));
                fs.writeFileSync(filePath, output);
            } catch (ex) {
                console.error("There was a problem writing the output file:\n%s", ex);
                return false;
            }
        } else {
            console.log(output);
        }
    }

    return true;

}

/**
 * Checks if the given message is an error message.
 * @param {object} message The message to check.
 * @returns {boolean} Whether or not the message is an error message.
 */
function isErrorMessage(message) {
    return message.severity === 2;
}

/**
 * Returns results that only contains errors.
 * @param {LintResult[]} results The results to filter.
 * @returns {LintResult[]} The filtered results.
 */
function getErrorResults(results) {
    var filtered = [];

    results.forEach(function (result) {
        var filteredMessages = result.messages.filter(isErrorMessage);

        if (filteredMessages.length > 0) {
            filtered.push({
                filePath: result.filePath,
                messages: filteredMessages
            });
        }
    });

    return filtered;
}

//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------

/**
 * Encapsulates all CLI behavior for eslint. Makes it easier to test as well as
 * for other Node.js programs to effectively run the CLI.
 */
var cli = {

    /**
     * Executes the CLI based on an array of arguments that is passed in.
     * @param {string|Array|Object} args The arguments to process.
     * @param {string} [text] The text to lint (used for TTY).
     * @returns {int} The exit code for the operation.
     */
    execute: function(args, text) {

        var currentOptions,
            files,
            result,
            engine;

        try {
            currentOptions = options.parse(args);
        } catch (error) {
            console.error(error.message);
            return 1;
        }

        files = currentOptions._;

        if (currentOptions.version) { // version from package.json

            console.log("v" + require("../package.json").version);

        } else if (currentOptions.help || (!files.length && !text)) {

            console.log(options.generateHelp());

        } else {

            engine = new CLIEngine(translateOptions(currentOptions));
            debug("Running on " + (text ? "text" : "files"));

            result = text ? engine.executeOnText(text, currentOptions.stdinFilename) : engine.executeOnFiles(files);
            if (currentOptions.quiet) {
                result.results = getErrorResults(result.results);
            }

            if (printResults(engine, result.results, currentOptions.format, currentOptions.outputFile)) {
                return result.errorCount ? 1 : 0;
            } else {
                return 1;
            }

        }

        return 0;
    }
};

module.exports = cli;