var FILE = require("file"),
    OS = require("os"),
    ObjectiveJ = require("objective-j");

require("objective-j/rhino/regexp-rhino-patch");

ObjectiveJ.Preprocessor.Flags.Preprocess   = 1 << 10;
ObjectiveJ.Preprocessor.Flags.Compress     = 1 << 11;
ObjectiveJ.Preprocessor.Flags.CheckSyntax  = 1 << 12;

var compressors = {
    ss  : { id : "minify/shrinksafe" }
    //,yui : { id : "minify/yuicompressor" }
    // ,cc  : { id : "minify/closure-compiler" }
};
var compressorStats = {};
function compressor(code) {
    var winner, winnerName;
    compressorStats['original'] = (compressorStats['original'] || 0) + code.length;
    for (var name in compressors) {
        var compressor = require(compressors[name].id);
        var result = compressor.compress(code, { charset : "UTF-8", useServer : true });
        compressorStats[name] = (compressorStats[name] || 0) + result.length;
        if (!winner || result < winner.length) {
            winner = result;
            winnerName = name;
        }
    }
    // print("winner="+winnerName+" compressorStats="+JSON.stringify(compressorStats));
    return winner;
}

function compileWithResolvedFlags(aFilePath, objjcFlags, gccFlags)
{
    var shouldObjjPreprocess = objjcFlags & ObjectiveJ.Preprocessor.Flags.Preprocess,
        shouldCheckSyntax = objjcFlags & ObjectiveJ.Preprocessor.Flags.CheckSyntax,
        shouldCompress = objjcFlags & ObjectiveJ.Preprocessor.Flags.Compress,
        fileContents = "";

    if (OS.popen("which gcc").stdout.read().length === 0)
        fileContents = FILE.read(aFilePath, { charset:"UTF-8" });

    else
    {
        // GCC preprocess the file.
        var gcc = OS.popen("gcc -E -x c -P " + (gccFlags ? gccFlags.join(" ") : "") + " " + OS.enquote(aFilePath), { charset:"UTF-8" }),
            chunk = "";

        while (chunk = gcc.stdout.read())
            fileContents += chunk;
    }

    if (!shouldObjjPreprocess)
        return fileContents;

    // Preprocess contents into fragments.
    // FIXME: should calculate relative path, etc.
    try
    {
        var executable = ObjectiveJ.preprocess(fileContents, FILE.basename(aFilePath), objjcFlags);
    }
    catch (anException)
    {print(anException);
        var lines = fileContents.split("\n"),
            PAD = 3,
            lineNumber = anException.lineNumber || anException.line,
            errorInfo = "Syntax error in " + aFilePath +
                        " on preprocessed line number " + lineNumber + "\n\n" +
                        "\t" + lines.slice(Math.max(0, lineNumber - 1 - PAD), lineNumber + PAD).join("\n\t");

        print(errorInfo);

        throw errorInfo;
    }

    if (shouldCompress)
    {
        var code = executable.code();
        code = compressor("function(){" + code + "}");
        // more robust function wrapper stripping
        code = code.replace(/^\s*function\s*\(\s*\)\s*{|}\s*;?\s*$/g, "");
        executable.setCode(code);
    }

    return executable.toMarkedString();
}

function resolveFlags(args)
{
    var filePaths = [],
        outputFilePaths = [],

        index = 0,
        count = args.length,

        gccFlags = [],
        objjcFlags = ObjectiveJ.Preprocessor.Flags.Preprocess | ObjectiveJ.Preprocessor.Flags.CheckSyntax;

    for (; index < count; ++index)
    {
        var argument = args[index];
        
        if (argument === "-o")
        {
            if (++index < count)
                outputFilePaths.push(args[index]);
        }
        
        else if (argument.indexOf("-D") === 0)
            gccFlags.push(argument)
            
        else if (argument.indexOf("-U") === 0)
            gccFlags.push(argument);

        else if (argument === "--include")
        {
            if (++index < count)
            {
                gccFlags.push(argument);
                gccFlags.push(args[index]);
            }
        }

        else if (argument.indexOf("-E") === 0)
            objjcFlags &= ~ObjectiveJ.Preprocessor.Flags.Preprocess;
            
        else if (argument.indexOf("-S") === 0)
            objjcFlags &= ~ObjectiveJ.Preprocessor.Flags.CheckSyntax;
            
        else if (argument.indexOf("-g") === 0)
            objjcFlags |= ObjectiveJ.Preprocessor.Flags.IncludeDebugSymbols;
            
        else if (argument.indexOf("-O") === 0)
            objjcFlags |= ObjectiveJ.Preprocessor.Flags.Compress;

        else
            filePaths.push(argument);
    }

    return { filePaths:filePaths, outputFilePaths:outputFilePaths, objjcFlags:objjcFlags, gccFlags:gccFlags };
}

exports.compile = function(aFilePath, flags)
{
    if (flags.split)
        flags = flags.split(/\s+/);

    var resolvedFlags = resolveFlags(flags);

    return compileWithResolvedFlags(aFilePath, resolvedFlags.objjcFlags, resolvedFlags.gccFlags);
}

exports.main = function(args)
{
    // TODO: args parser
    args.shift();

    var resolved = resolveFlags(args),
        outputFilePaths = resolved.outputFilePaths,
        objjcFlags = resolved.objjcFlags,
        gccFlags = resolved.gccFlags;

    resolved.filePaths.forEach(function(filePath, index)
    {
        print("Statically Compiling " + filePath);

        FILE.write(outputFilePaths[index], compileWithResolvedFlags(filePath, objjcFlags, gccFlags), { charset: "UTF-8" });
    });
}

if (require.main == module.id)
    exports.main(system.args);