#!/usr/bin/env python
from __future__ import absolute_import
from __future__ import print_function
from six.moves import input
__doc__ = r"""
Module to diff two images or directories full of images.

Can by used from the command line via:
   python imagediff.py file1 file2
   python imagediff.py dir1 dir2 [dir3]
In the latter case dir1 and dir2 are any two directories and all
images will be compared.  The optional dir3 argument gives the directory
for the resulting diff's and html files.  Default is '_image_diff'.

Command line flags include:
    -v, --verbose = Verbose output   
    -r, --relocatable = Copy original image files to dir3 also
    -h, --help = Display this help
"""

help_message = __doc__

import os, sys, getopt, shutil

def imagediff_file(fname1, fname2, verbose=True):
    
    fname3 = make_imagediff(fname1,fname2,verbose=verbose)
    
    hfile = "imagediff.html"
    html = open(hfile,"w")
    html.write("""
         <html>
         <h2>Comparison of image files</h2>
         Left: %s <br>
         Right: %s
         <p>
         <img src="%s" width=400 border="1"> &nbsp; <img src="%s" width=400 border="1">""" \
      % (fname1,fname2,fname1,fname2))
      
    html.write("""
         <h2>Pixel difference is nonzero where image below is black...</h2>
         <img src="%s" width=400 border="1">""" % fname3)
    html.close()
    print("To view comparision and pixelwise difference, see ", hfile)
    
    
         
def make_imagediff(fname1,fname2,fname3='', verbose=False):
    ext1 = os.path.splitext(fname1)[1]
    ext2 = os.path.splitext(fname2)[1]
    if ext1 != ext2:
        print("*** Error: extensions of fname1 and fname2 must agree")
        return
    if ext1 not in ['.png','.gif','.jpg']:
        print("*** Error: image files not recognized")
        return
    
    if fname3 == '':
        fname3 = "_image_diff" + ext1
    
    os.system("convert %s %s -compose subtract -composite -threshold 0.001 -negate %s" \
         % (fname1, fname2, fname3))
    
    if verbose:     
        print("Created pixelwise difference ", fname3)
    return fname3
    
    
def imagediff_dir(dir1, dir2, dir3="_image_diff", ext='.png', \
                  regression_test_files='all',  \
                  relocatable=False, overwrite=False, verbose=False):
    
    import filecmp,glob
    from numpy import alltrue
    
    if dir1[-1] == '/': dir1 = dir1[:-1]
    if dir2[-1] == '/': dir2 = dir2[:-1]
    dir1 = os.path.abspath(dir1)
    dir2 = os.path.abspath(dir2)
    
    
    files1 = glob.glob("%s/*%s" % (dir1,ext))    
    files1 = [f.replace(dir1+'/','') for f in files1]
    files2 = glob.glob("%s/*%s" % (dir2,ext))
    files2 = [f.replace(dir2+'/','') for f in files2]
    
    files_both = files1 + files2
    files = []
    for f in files_both:
        if f not in files: files.append(f)
    files.sort()
    
    print("Comparing files in the  directory: ", dir1)
    print("               with the directory: ", dir2)

    if os.path.isdir(dir3):
        if (len(os.listdir(dir3)) > 0)  and (not overwrite):
            ans = input("Ok to overwrite files in %s ?  " % dir3)
            if ans.lower() not in ['y','yes']:
                print("*** Aborting")
                return
    else:
        os.system('mkdir -p %s' % dir3)
    startdir = os.getcwd()


    
    
    os.chdir(dir3)
            
    hname = '_ImageDiffIndex.html'
    hfile = open(hname,'w')
    hfile.write("""<html>
            <h1>Figure comparison and pixel diff</h1>
            Comparing files in the directory: &nbsp; dir1 = %s<br>
            &nbsp;&nbsp; with the directory: &nbsp; dir2 = %s<br>
            &nbsp;&nbsp; with the image extension: %s<p>
            &nbsp;<p>
            <h2>Files:</h2>
            """ % (dir1,dir2,ext))
            
    f_equal, f_diff, f_other = filecmp.cmpfiles(dir1,dir2,files,False)

    if relocatable:
        # copy files from dir1 and dir2 into dir3 so the whole thing can
        # be moved elsewhere, e.g. to post on web for discussion of a bug.
        dir1copy = 'dir1'
        dir2copy = 'dir2'
        os.system('mkdir %s' % dir1copy)
        os.system('mkdir %s' % dir2copy)
        for f in files1:
            shutil.copy(os.path.join(dir1,f),dir1copy)
            ## Specific to Clawpack _plots, also want html file:
            fhtml = os.path.splitext(f)[0] + '.html'  
            if os.path.isfile(os.path.join(dir1,fhtml)): 
                shutil.copy(os.path.join(dir1,fhtml),dir1copy)

        for f in files2:
            shutil.copy(os.path.join(dir2,f),dir2copy)
            ## Specific to Clawpack _plots, also want html file:
            fhtml = os.path.splitext(f)[0] + '.html'  
            if os.path.isfile(os.path.join(dir2,fhtml)): 
                shutil.copy(os.path.join(dir2,fhtml),dir2copy)

        dir1 = 'dir1'
        dir2 = 'dir2'

    files_missing1 = []
    files_missing2 = []
    files_differ = []
    
    for f in files:
        fhtml = os.path.splitext(f)[0] + '.html'  ## Specific to Clawpack _plots
        if not os.path.isfile(os.path.join(dir1,fhtml)): fhtml = f
          
        fname1 = os.path.join(dir1,f)
        fname2 = os.path.join(dir2,f)
        fhtml1 = os.path.join(dir1,fhtml)
        fhtml2 = os.path.join(dir2,fhtml)

        if f not in files2:
            files_missing2.append(f)
            hfile.write("""
              <table>
              <tr><td><b>%s</b> only appears in dir1</td></tr>
              <tr>
              <td><a href="%s"><img src="%s" width=350 border="1"></a></td> &nbsp; &nbsp;
              <td><img src="XXmissingXX" width=350 height=250 border="1"></td>
              </tr>
              </table><p>"""  % (f, fhtml1, fname1))
        elif f not in files1:
            files_missing1.append(f)
            hfile.write("""
              <table>
              <tr><td></td><td><b>%s</b> only appears in dir2</td></tr>
              <tr>
              <td><img src="XXmissingXX" width=350 height=250 border="1"></td>&nbsp;&nbsp;
              <td><a href="%s"><img src="%s" width=350 border="1"></a></td> &nbsp; 
              </tr>
              </table><p>"""  % (f, fhtml2, fname2))
            
        elif f in f_equal:
            fname1 = os.path.join(dir1,f)
            hfile.write("""
              <table>
              <tr><td><b>%s</b> are identical in dir1 and dir2</td></tr>
              <tr>
              <td><a href="%s"><img src="%s" width=350 border="1"></a></td> &nbsp;&nbsp; 
              </tr>
              </table><p>"""  % (f, fhtml1, fname1))
            # hfile.write("""
            #               <a href="%s"><img src="%s" width=350 border="1"></a>""" \
            #                 % (fname1,fname1))
        else:
            files_differ.append(f)
            fname3 = f

            fname3 = make_imagediff(fname1,fname2,fname3,verbose=verbose)
            hfile.write("""
              <table>
              <tr><td><b>%s</b> from dir1</td><td><b>%s</b>  from dir2</td>
                  <td>Pixels that differ between the images</td>  </tr>
              <tr>
              <td><a href="%s"><img src="%s" width=350 border="1"></a></td> &nbsp;&nbsp; 
              <td><a href="%s"><img src="%s" width=350 border="1"></a></td> &nbsp;&nbsp; 
              <td><a href="%s"><img src="%s" width=350 border="1"></a></td>  </tr>
              </table><p>""" \
                % (f,f,fhtml1,fname1,fhtml2,fname2,fname3,fname3))

    # Test regression files for return value:
    if regression_test_files=='all':
        regression_test_files = files_both
    regression_ok = alltrue([f in f_equal for f in \
                                regression_test_files])
    if verbose and regression_ok:
        print("Regression files all match")
    elif verbose:
        print("*** Regression files are not all identical")
        print("*** Files missing from dir1:   ",files_missing1)
        print("*** Files missing from dir2:   ",files_missing2)
        print("*** Files that differ:   ",files_differ)
        
    os.chdir(startdir)
    dir3 = os.path.abspath(dir3)
    print("To view diffs, open the file ",os.path.join(dir3,hname))

    return regression_ok
    

class Usage(Exception):
    def __init__(self, msg):
        self.msg = msg


if __name__ == "__main__":    
    # Parse input arguments
    argv = sys.argv
    try:
        try:
            opts, args = getopt.getopt(argv[1:], "hv",["help","verbose","relocatable"])
        except getopt.error as msg:
            raise Usage(msg)

        # Default script parameter values
        verbose = False
        relocatable = False

        # option processing
        for option, value in opts:
            # Script parameters
            if option in ("-v","--verbose"):
                 verbose = True
            if option in ("-r","--relocatable"):
                 relocatable = True
            if option in ("-h","--help"):
                raise Usage(help_message)

        # Run diff
        if os.path.isfile(args[0]) and os.path.isfile(args[1]):
            sys.exit(imagediff_file(args[0],args[1],verbose=verbose))
        elif os.path.isdir(args[0]) and os.path.isdir(args[1]):
            if len(args)==3:
                sys.exit(imagediff_dir(args[0],args[1],args[2],verbose=verbose,\
                     relocatable=relocatable))
            else:
                sys.exit(imagediff_dir(args[0],args[1],verbose=verbose,\
                     relocatable=relocatable))
        else:
              raise Usage("Both paths must either be files or directories.")
        
    except Usage as err:
        print(sys.argv[0].split("/")[-1] + ": " + str(err.msg), file=sys.stderr)
        print("\t for help use --help", file=sys.stderr)
        sys.exit(2)
    
    
        
        
        
