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

var filterErr = function(code, done) {
    return function (e) {
			done(e.code !== code ? e : undefined);
		};
};

var throwErr = function(done) {
    return function (e) {
			if (e)
				throw e;
			
			done();
		};
};
 
// apply function to elements of array. Return first true value to done or undefined.
var mapOr = function(func, array, done) {
    if (array.length) {
		func(array[array.length-1], function (v) {
				if (v) {
					done(v);
				}
				else {
					array.length -= 1;
					mapOr(func, array, done);
				}
			});
    }
    else {
		done();
    }
};

// Make a directory and sub-directories.
var mkPath = function(dirPath, mode, done) {
    fs.mkdir(dirPath, typeof mode === "string" ? parseInt(mode, 8) : mode, function (e) {
	    if (e && e.code === "EEXIST") {
			// Already exists, done.
			done();
	    }
	    else if (e.code === "ENOENT") {
			// Missing sub dir.

			mkPath(path.dirname(dirPath), mode, function(e) {
					if (e) {
						throw e;
					}
					else {
						mkPath(dirPath, mode, done);
					}
				});
	    }
	    else {
			throw e;
	    }
	});
};

// Empty a directory.
var emptyPath = function(dirPath, done) {
    fs.readdir(dirPath, function (err, files) {
	if (err) {
	    done(err);
	}
	else {
	    mapOr(rmPath, files.map(function(f) { return path.join(dirPath, f); }), done);
	}
    });
};

// Remove path recursively.
var rmPath = function(dirPath, done) {
//  console.log("rmPath: %s", dirPath);

    fs.lstat(dirPath, function (err, stats) {
			if (err && err.code == "ENOENT") {
				done();
			}
			if (err) {
				done(err);
			}
			else if (stats.isDirectory()) {
				emptyPath(dirPath, function (e) {
						if (e) {
							done(e);
						}
						else {
//							console.log("rmdir: %s", dirPath); done();
							fs.rmdir(dirPath, done);
						}
					});
			}
			else {
//				console.log("unlink: %s", dirPath); done();
				fs.unlink(dirPath, done);
			}
		});
};

// Create directory if needed and empty if needed.
var resetPath = function(dirPath, mode, done) {
    mkPath(dirPath, mode, function (e) {
			if (e) {
				done(e);
			}
			else {
				emptyPath(dirPath, done);
			}
		});
};

var trace = function(comment, func) {
    return function() {
			console.log("%s: %s", trace, arguments.toString);
			func(arguments);
		};
};

exports.emptyPath   = emptyPath;
exports.mapOr	    = mapOr;
exports.mkPath	    = mkPath;
exports.resetPath   = resetPath;
exports.rmPath	    = rmPath;
exports.trace	    = trace;

// vim:ts=4