#!/usb/bin/env python

import os
import dropbox
import shutil
import zipfile

# Create a dropbox app and obtain App Key and Secret Key. Specify a folder
# Create a folder called romsync in your specified Dropbox app folder
# Store Dropbox App Key and Secret Key in system environment variables
app_key = os.getenv('DROPBOX_ROMSYNC_APP_KEY')
app_secret = os.getenv('DROPBOX_ROMSYNC_SECRET_KEY')

DEBUG = 0
CFG_DEFAULT = os.path.join(os.getenv('HOME'), '.romsync')


# A Config object to store and load settings
class Config(object):
    settings = {}
    path = ''

    def __init__(self, path=CFG_DEFAULT):
        self.path = path
        self.load()

    # Return value of setting
    def get(self, key):
        return self.settings[key]

    # Update the cursor
    def set_cursor(self, cursor):
        self.settings['cursor'] = cursor

    # Write settings to config
    def save(self):
        open(self.path, 'w').close()  # Flush config before writing
        with open(self.path, 'w') as cfg:
            for key in self.settings:
                cfg.write(key + '=' + self.settings[key] + '\n')

    # Load settings from config
    # return: True if config exists, False otherwise
    def load(self):
        if os.path.isfile(self.path):
            with open(self.path, 'r') as cfg:
                for line in cfg:
                    key = line.replace(" ", "").split('=')[0]
                    value = line.replace(" ", "").split('=')[1].rstrip()
                    self.settings[key] = value
            return True
        else:
            with open(self.path, 'w') as cfg:
                # Generate authorization code
                flow = dropbox.client.DropboxOAuth2FlowNoRedirect(app_key, app_secret)
                authorize_url = flow.start()

                print('1. Go to: ' + authorize_url)
                print('2. Click "Allow" (you might have to log in first)')
                print('3. Copy the authorization code.')
                code = raw_input('Enter the authorization code here: ').strip()
                local_path = raw_input('Enter your local roms directory: ')

                access_token, user_id = flow.finish(code)

                # Write default settings to config 
                cfg.write('access_token=' + access_token + '\n')
                cfg.write('db_roms=/romsync\n')
                cfg.write('local_roms=' + local_path + '\n')
                cfg.write('cursor= ' + '\n')

                return False


# Download/remove files and directories
# return: dictionary of modified files
def delta_sync(client, delta, config):
    dirs = []
    files = []

    file_change = {'added': [], 'removed': []}
    entries = delta['entries']
    local_path = config.get('local_roms')
    db_path = config.get('db_roms')

    for e in entries:
        path = e[0].replace(db_path, local_path)
        if e[1] is None:
            try:
                if e[1]['is_dir']:
                    if len(path) > 0:
                        os.makedirs(path)
                else:
                    out = open(path, 'wb')
                    with client.get_file(e[1]['path']) as rom:
                        out.write(rom.read())
                    file_change['added'].append(path.replace(local_path, ''))
                    if out.endswith('.zip'):
                        z = zipfile.ZipFile(out)
                        z.extractall(path)
                        z.close()
                        del z
                        os.unlink(out)
                        print out.name + " extracted and deleted"
            except:
                if DEBUG:
                    print(path, ' already exists')
        else:
            try:
                if os.path.isdir(path):
                    shutil.rmtree(path)
                    for child in os.listdir(path):
                        file_change['removed'].append(child)
                else:
                    os.remove(path)
                    file_change['removed'].append(path.replace(local_path, ''))
            except:
                if DEBUG:
                    print(path, ' does not exist')

    return file_change


def main():
    config = Config()
    config_exists = config.load()

    # Get client
    client = dropbox.client.DropboxClient(config.get('access_token'))
    delta = client.delta(path_prefix=config.get('db_roms'), cursor=config.get('cursor'))
    if DEBUG:
        print(delta)

    # Sync files
    # Report added and removed files
    if len(delta['entries']) > 0:
        print('Syncing roms...')

        file_change = delta_sync(client, delta, config)
        added = len(file_change['added'])
        removed = len(file_change['removed'])

        if added > 0:
            print('\n' + 'Fetched %s rom(s)' % str(added))
            for entry in file_change['added']:
                rom = entry.split(os.sep)
                print(rom[0] + ' - ' + rom[1])
        if removed > 0:
            print('\n' + 'Removed %s rom(s)' % str(removed))
            for entry in file_change['removed']:
                print(entry)
        print('')
    else:
        print('No need to sync')

    # Update config with new cursor
    config.set_cursor(delta['cursor'])
    config.save()


if __name__ == "__main__":
    main()