Update 'README.md'

README.md

@@ -1,2 +1,79 @@
 # gpt-migrate
 
+gpt 不同语言代码迁移，比如java项目转python项目
+
+
+## Develop
+
+```
+python main.py --sourcedir /path/to/my-python-app --sourceentry app.py --targetdir /path/to/my-nodejs-app --targetlang nodejs
+```
+--sourcedir 指定原项目目录，--targetlang指定目标语言，如nodejs
+
+## 原理分析
+
+1、检测 sourcedir 是什么语言的代码：
+```
+    detected_language = detect_language(sourcedir) if not sourcelang else sourcelang
+
+```
+在 config.py 中，定义了常见的编程语言，detect_language 函数遍历 sourcedir 目录，找出后缀最多的文件的后缀，然后再确定是哪种编程语言。
+
+2、创建环境
+
+```
+        create_environment(globals)
+
+    docker_prompt_template = prompt_constructor(HIERARCHY, GUIDELINES, WRITE_CODE, CREATE_DOCKER, SINGLEFILE)
+```
+其实就是拼接 prompt , 替换 targetlang，targetdir 等几个变量：
+
+```
+    llm_write_file(prompt,
+                    target_path="Dockerfile",
+                    waiting_message="Creating your environment...",
+                    success_message=f"Created Docker environment for {globals.targetlang} project in directory '{globals.targetdir}'.",
+                    globals=globals)
+```
+prompt 模板在 gpt_migrate/prompts 目录中。注意，llm_write_file 函数写Dockerfile，怎么写呢？上面只是拼接了模板的 prompt而已，那这些 prompt 其实是调用openai来生成的：
+
+```
+
+        file_name,language,file_content = globals.ai.write_code(prompt)[0]
+        
+        
+            
+    def write_code(self, prompt):
+        message=[{"role": "user", "content": str(prompt)}] 
+        response = openai.ChatCompletion.create(
+            messages=message,
+            stream=False,
+            model=self.model_name,
+            max_tokens=self.max_tokens,
+            temperature=self.temperature
+        )
+
+```
+
+
+3、代码迁移，如java代码迁移到python语言：
+
+```
+        def migrate(sourcefile, globals, parent_file=None):
+            # recursively work through each of the files in the source directory, starting with the entrypoint.
+            internal_deps_list, external_deps_list = get_dependencies(sourcefile=sourcefile,globals=globals)
+            for dependency in internal_deps_list:
+                migrate(dependency, globals, parent_file=sourcefile)
+            file_name = write_migration(sourcefile, external_deps_list, target_deps_per_file.get(sourcefile), globals)
+            target_deps_per_file[parent_file].append(file_name)
+
+        migrate(sourceentry, globals)
+```
+
+仔细看发现 migrate 采用了递归，
+
+```
+    external_deps_prompt_template = prompt_constructor(HIERARCHY, GUIDELINES, GET_EXTERNAL_DEPS)
+
+```
+这里 prompt 发生了变化，GET_EXTERNAL_DEPS