import re
import os
import shutil

def filename2Wikilink( s ):
    return '{' + s.replace('_',' ').replace('.gmo','') + '}'

def wikilink2Filename( s, ext='.gmi' ):
    return s.strip("{}").replace(' ','_') + ext

os.chdir('src/')

incoming = {}

for filename in os.listdir():
    if filename.endswith('.gmo'):
        # copy to tmp 
        shutil.copy(filename, '../tmp/'+filename)

#        if filename != 'pages.gmo' and filename != 'index.gmo':
        if filename != 'pages.gmo':
            # convert filename to wikilink
            wikilink=filename2Wikilink(filename)
            if wikilink not in incoming:
                incoming[wikilink] = set()

            # open file and search for all outgoing links
            file = open(filename)
            pre_mode = False
            for line in file:
                if re.match("```",line) != None: # toggle preformatted mode
                    pre_mode = not pre_mode
                if pre_mode: # skip preformatted mode
                    continue
                m=re.search("\{.+\}",line)
                if m:
                    match = m.group(0) # get matched string
                    if match not in incoming: # create a new set for that page
                        incoming[match] = set()
                    # add this file
                    incoming[match].add(wikilink)
            file.close()

os.chdir('../tmp/')

# remove incoming links for:
# incoming.pop('{pages}')
incoming.pop('{home}')
#incoming.pop('{license}')

for key,links in incoming.items():
    # get filename for key
    filename = wikilink2Filename(key,'.gmo')
#    print(key)

    # open file in append mode
    file = open(filename, 'a') 

    if len(links):
        # write incoming links
#        print( '{} incoming links\n'.format( len(links) ) )
        file.write("\n\n# incoming links\n")
        for link in links:
            gemlink = '=> ./{} {}'.format(wikilink2Filename(link), link) 
#            print(gemlink)
            file.write(gemlink+"\n")
    else:
        print( '{}: orphan\n'.format(key) )
        file.write("\n\nno incoming links\n")
    file.close()