link-tool now could generate configuration

link-tool.py

@@ -2,11 +2,26 @@
 
 import argparse
 import dataclasses
-import os
 import logging
+import os
+import sys
 
+
+from string import Template
 from typing import List, Tuple, Union
 
+
+configuration_template = Template(
+'''
+cwd = $cwd
+
+# Generated by link-tool.py
+#    $link_tool_cmd
+
+$link_rules
+''')
+
+
 logger = logging.getLogger(__name__)
 
 @dataclasses.dataclass(repr=True)
@@ -87,6 +102,38 @@ def make_link(links: List[Link], dry_run=False, overwrite=False):
         if not dry_run:
             os.link(link.src, link.dst)
 
+def generate_configuration(src: str, dst: str, config_path: str):
+    config_path_depth = config_path.strip('/').count('/')
+    cwd = '.' if config_path_depth == 0 else '..' + '/..' * (config_path_depth - 1)
+
+    logger.info('configuration: cwd: {}'.format(cwd))
+
+    link_rules = []
+    for dirname, _, files in os.walk(src):
+        for file in files:
+            link_rules.append(Link(src=os.path.join(dirname, file),
+                                   dst=os.path.join(dst, os.path.basename(file))))
+
+    max_src_file_path_len = max([len(l.src) for l in link_rules])
+    formater = '{:%d} -> {}' % max_src_file_path_len
+    link_rules_str = ''
+    for l in link_rules:
+        link_rules_str += formater.format(l.src, l.dst) + '\n'
+
+    configuration_str = configuration_template.safe_substitute(
+        cwd=cwd,
+        link_rules=link_rules_str,
+        link_tool_cmd="'{}'".format("' '".join(sys.argv)))
+
+    # create parent dir for configuration file
+    configuration_dir = os.path.dirname(config_path)
+    if not os.path.exists(configuration_dir):
+        os.makedirs(configuration_dir)
+
+    # write configuration file
+    with open(config_path, 'w', encoding='utf-8') as f:
+        f.write(configuration_str)
+
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument('-c', '--config', required=True,
@@ -98,26 +145,43 @@ def main():
     parser.add_argument('-v', '--verbose', action='store_true',
                         help='more verbose log')
 
+    parser.add_argument('-g', '--generate', action='store_true',
+                        help='generate configuration with a predefined template, '
+                        'need other arguments. When this argument is used, '
+                        'the generated configuration will be place to the path of --config')
+    parser.add_argument('--src', default=None,
+                        help='src directory, link rule will be generate for '
+                        'every file in this (sub)directory')
+    parser.add_argument('--dst', default=None,
+                        help='dst directory, link rule\'target directory')
+
     args = parser.parse_args()
 
-    config_path = args.config
-    verbose = args.verbose
+    logging.basicConfig(level=logging.DEBUG if args.verbose else logging.INFO)
+
+    if args.generate:
+        if args.src is None or args.dst is None:
+            logger.error('invalid argument, --src or --dst is not specified')
+            exit(1)
+        if '..' in args.config:
+            logger.error('configuration file path must not contain any \'..\'')
+        else:
+            generate_configuration(args.src, args.dst, args.config)
+    else:
         dry_run = args.dry_run
         overwrite = args.overwrite
 
-    logging.basicConfig(level=logging.DEBUG if verbose else logging.INFO)
-
-    config, links = load_config(config_path)
+        config, links = load_config(args.config)
 
         if not config.validate():
             logger.error('invalid configuration, exiting...')
             exit(1)
 
         for link in links:
-        logger.info('loaded link: {}'.format(link))
+            logger.debug('loaded link: {}'.format(link))
 
         assert(config.cwd is not None)
-    config_path_dir = os.path.dirname(config_path)
+        config_path_dir = os.path.dirname(args.config)
         chdir_target = os.path.join(config_path_dir, config.cwd)
         logger.info('changing CWD: {}/{}'.format(config_path_dir, config.cwd))
         logger.info('the CWD realpath: {}'.format(os.path.realpath(chdir_target)))