var path = require('path'),

fs = require('./fs'),
PromiseConstructor,
AbstractFileManager = require("../less/environment/abstract-file-manager.js");

try {

PromiseConstructor = typeof Promise === 'undefined' ? require('promise') : Promise;

} catch(e) { }

var FileManager = function() { };

FileManager.prototype = new AbstractFileManager();

FileManager.prototype.supports = function(filename, currentDirectory, options, environment) {

return true;

}; FileManager.prototype.supportsSync = function(filename, currentDirectory, options, environment) {

return true;

};

FileManager.prototype.loadFile = function(filename, currentDirectory, options, environment, callback) {

var fullFilename,
    data,
    isAbsoluteFilename = this.isPathAbsolute(filename),
    filenamesTried = [];

options = options || {};

if (options.syncImport || !PromiseConstructor) {
    data = this.loadFileSync(filename, currentDirectory, options, environment, 'utf-8');
    callback(data.error, data);
    return;
}

var paths = isAbsoluteFilename ? [""] : [currentDirectory];
if (options.paths) { paths.push.apply(paths, options.paths); }
if (!isAbsoluteFilename && paths.indexOf('.') === -1) { paths.push('.'); }

// promise is guarenteed to be asyncronous
// which helps as it allows the file handle
// to be closed before it continues with the next file
return new PromiseConstructor(function(fulfill, reject) {
    (function tryPathIndex(i) {
        if (i < paths.length) {
            fullFilename = filename;
            if (paths[i]) {
                fullFilename = path.join(paths[i], fullFilename);
            }
            fs.stat(fullFilename, function (err) {
                if (err) {
                    filenamesTried.push(fullFilename);
                    tryPathIndex(i + 1);
                } else {
                    fs.readFile(fullFilename, 'utf-8', function(e, data) {
                        if (e) { reject(e); return; }

                        fulfill({ contents: data, filename: fullFilename});
                    });
                }
            });
        } else {
            reject({ type: 'File', message: "'" + filename + "' wasn't found. Tried - " + filenamesTried.join(",") });
        }
    }(0));
});

};

FileManager.prototype.loadFileSync = function(filename, currentDirectory, options, environment, encoding) {

var fullFilename, paths, filenamesTried = [], isAbsoluteFilename = this.isPathAbsolute(filename) , data;
options = options || {};

paths = isAbsoluteFilename ? [""] : [currentDirectory];
if (options.paths) {
    paths.push.apply(paths, options.paths);
}
if (!isAbsoluteFilename && paths.indexOf('.') === -1) {
    paths.push('.');
}

var err, result;
for (var i = 0; i < paths.length; i++) {
    try {
        fullFilename = filename;
        if (paths[i]) {
            fullFilename = path.join(paths[i], fullFilename);
        }
        filenamesTried.push(fullFilename);
        fs.statSync(fullFilename);
        break;
    } catch (e) {
        fullFilename = null;
    }
}

if (!fullFilename) {
    err = { type: 'File', message: "'" + filename + "' wasn't found. Tried - " + filenamesTried.join(",") };
    result = { error: err };
} else {
    data = fs.readFileSync(fullFilename, encoding);
    result = { contents: data, filename: fullFilename};
}

return result;

};

module.exports = FileManager;