feature(spider/nhentai): add favors login nhentai command

README.md

@@ -70,9 +70,16 @@ favors login yandere -u {username}
 ```
 
 ## Login NHentai
-1. Open nhentai on browser and login.
-2. Use "Get cookies.txt" browser extension download cookie file.
-3. Copy cookie file to {user_home}/.favorites_crawler.
+1. Get User-Agent and Cookie File
+   1. Open nhentai and login.
+   2. Open dev console (F12) and switch to network tab.
+   3. Open any comic.
+   4. Copy user-agent from any request.
+   5. Use "Get cookies.txt" browser extension download cookie file.
+2. Execute command:
+   ```commandline
+   favors login nhentai -u "{User-Agent}" -c "{Cookie File}"
+   ```
 
 ## Login Twitter
 

src/favorites_crawler/commands/login.py

@@ -114,3 +114,35 @@ def login_twitter(
         return
     dump_config(config)
     print("Login successful.")
+
+
+@app.command("nhentai")
+def login_nhentai(
+        user_agent: str = typer.Option(
+            ..., '-u', '--user-agent',
+            help='User Agent'
+        ),
+        cookie_file: str = typer.Option(
+            ..., '-c', '--cookie-file',
+            help='Netscape HTTP Cookie File, you can download it by "Get cookies.txt" browser extension.'
+        )
+):
+    """
+    Login to nhentai.
+
+    1. Open nhentai and login.\n
+    2. Open dev console (F12) and switch to network tab.\n
+    3. Open any comic.\n
+    4. Copy user-agent from any request.\n
+    5. Use "Get cookies.txt" browser extension download cookie file.
+    """
+    config = load_config()
+    nhentai_config = config.setdefault('nhentai', {})
+    try:
+        nhentai_config['USER_AGENT'] = user_agent
+        shutil.copy(cookie_file, DEFAULT_FAVORS_HOME)
+    except Exception as e:
+        print(f"Failed to login: {e!r}")
+        return
+    dump_config(config)
+    print("Login successful.")