var common = require('./common');

var fs = require('fs');

//@

//@ ### grep([options,] regex_filter, file [, file ...])

//@ ### grep([options,] regex_filter, file_array)

//@ Available options:

//@

//@ + `-v`: Inverse the sense of the regex and print the lines not matching the criteria.

//@ + `-l`: Print only filenames of matching files

//@

//@ Examples:

//@

//@ ```javascript

//@ grep('-v', 'GLOBAL_VARIABLE', '*.js');

//@ grep('GLOBAL_VARIABLE', '*.js');

//@ ```

//@

//@ Reads input string from given files and returns a string containing all lines of the

//@ file that match the given `regex_filter`.

function _grep(options, regex, files) {

options = common.parseOptions(options, {

'v': 'inverse',

'l': 'nameOnly'

});

// Check if this is coming from a pipe

var pipe = common.readFromPipe(this);

if (!files && !pipe)

common.error('no paths given', 2);

files = [].slice.call(arguments, 2);

if (pipe)

files.unshift('-');

var grep = [];

files.forEach(function(file) {

if (!fs.existsSync(file) && file !== '-') {

common.error('no such file or directory: ' + file, 2, true);

return;

}

var contents = file === '-' ? pipe : fs.readFileSync(file, 'utf8');

var lines = contents.split(/\r*\n/);

if (options.nameOnly) {

if (contents.match(regex))

grep.push(file);

} else {

lines.forEach(function(line) {

var matched = line.match(regex);

if ((options.inverse && !matched) || (!options.inverse && matched))

grep.push(line);

});

}

});

return new common.ShellString(grep.join('\n')+'\n', common.state.error, common.state.errorCode);

}

module.exports = _grep;