import os
from optparse import make_option
from django.core.management.base import BaseCommand, CommandError

class Command(BaseCommand):
    option_list = BaseCommand.option_list + (
        make_option('-m','--method', action='store', dest='method', 
            type='choice', choices=['jsmin', 'jspacker'],
            help='Packing or minimization method (jsmin/jspacker)'),
        make_option('-f','--file', action='append', dest='build_file', default=[],
            help='Build only this output file'),
    )
    help = "Builds minimized/compacted javascript files"
    
    def handle(self, *args, **options):
        from django.conf import settings
        
        try:
            method = getattr(settings, 'JSC_METHOD')
        except AttributeError:
            method = None
        method = options.get('method') or method or 'jsmin'
        build_files = options.get('build_file', [])
        try:
            path = getattr(settings, 'JSC_PATH')
        except AttributeError:
            raise CommandError("Missing JSC_PATH in settings")
        try:
            filesdef = getattr(settings, 'JSC_FILES')
        except AttributeError:
            raise CommandError("Missing JSC_FILES in settings")
        
        all_outfiles = [ outfilename for (outfilename, other) in filesdef ]
        for build_file in build_files:
            if not build_file in all_outfiles:
                raise CommandError("Output file %s not included in JSC_FILES settings" % build_file)
                
        #by default build all files
        if build_files == []:
             build_files = all_outfiles
        
        for outfilename, inputfilenames in filesdef:
            if outfilename in build_files:
                print "Building minimized %s" % outfilename
                build_minimized_file(path, outfilename, inputfilenames, method)

# Minimizes javascript using jsmin.py from http://javascript.crockford.com/jsmin.py.txt
# Packs using http://www.crowproductions.de/repos/main/public/packer/jspacker.py
def build_minimized_file(path, outfilename, inputfilenames, method):
    import jsmin
    import jspacker
    from StringIO import StringIO
    
    data = StringIO()
    for name in inputfilenames:
        try:
            f = file(os.path.join(path,name))
        except IOError:
            raise CommandError("Error reading %s" % os.path.join(path,name))
        data.write(f.read())
        data.write('\n')
    outfile = file(os.path.join(path,outfilename),'w')
    if method == 'jsmin':
        outfile.write(jsmin.jsmin(data.getvalue()))
    else:
        p = jspacker.JavaScriptPacker()
        outfile.write(p.pack(data.getvalue(), compaction=False, encoding=62, fastDecode=True))
    outfile.close()