"""Run tests in the farm subdirectory.  Requires nose."""

import filecmp, fnmatch, glob, os, shutil, sys
from coverage.files import FileLocator


def test_farm(clean_only=False):
    """A test-generating function for nose to find and run."""
    for fname in glob.glob("test/farm/*/*.py"):
        case = FarmTestCase(fname, clean_only)
        yield (case.execute,)


class FarmTestCase(object):
    def __init__(self, runpy, clean_only=False):
        self.dir, self.runpy = os.path.split(runpy)
        self.clean_only = clean_only

    def cd(self, newdir):
        cwd = os.getcwd()
        os.chdir(newdir)
        return cwd

    def execute(self):
        cwd = self.cd(self.dir)

        # Prepare a dictionary of globals for the run.py files to use.
        fns = "copy run compare clean".split()
        if self.clean_only:
            glo = dict([(fn, self.noop) for fn in fns])
            glo['clean'] = self.clean
        else:
            glo = dict([(fn, getattr(self, fn)) for fn in fns])
        
        execfile(self.runpy, glo)

        self.cd(cwd)

    def fnmatch_list(self, files, filepattern):
        """Filter the list of `files` to only those that match `filepattern`."""
        
        return [f for f in files if fnmatch.fnmatch(f, filepattern)]

    # Functions usable inside farm run.py files
    
    def noop(self, *args, **kwargs):
        """A no-op function to stub out run, copy, etc, when only cleaning."""
        pass
    
    def copy(self, src, dst):
        """Copy a directory."""

        shutil.rmtree(dst, ignore_errors=True)
        shutil.copytree(src, dst)

    def run(self, cmds, rundir="src"):
        """Run a list of commands.
        
        `cmds` is a string, commands separated by newlines.
        `rundir` is the directory in which to run the commands.
        
        """
        cwd = self.cd(rundir)
        for cmd in cmds.split("\n"):
            stdin, stdouterr = os.popen4(cmd)
            output = stdouterr.read()
            print output,
        self.cd(cwd)

    def compare(self, dir1, dir2, filepattern=None):
        dc = filecmp.dircmp(dir1, dir2)
        diff_files = self.fnmatch_list(dc.diff_files, filepattern)
        left_only = self.fnmatch_list(dc.left_only, filepattern)
        right_only = self.fnmatch_list(dc.right_only, filepattern)
        assert not diff_files, "Files differ: %s" % (diff_files)
        assert not left_only, "Files in %s only: %s" % (dir1, left_only)
        assert not right_only, "Files in %s only: %s" % (dir2, right_only)

    def clean(self, cleandir):
        shutil.rmtree(cleandir)


# So that we can run just one farm run.py at a time.
if __name__ == '__main__':
    op = sys.argv[1]
    if op == 'run':
        case = FarmTestCase(sys.argv[2])
        case.execute()
    elif op == 'clean':
        for test in test_farm(clean_only=True):
            test[0](*test[1:])
    else:
        print "Need an operation: run, clean"