Refactor: Move backend files to backend/ directory and split .gitignore

backend/src/ea_chatbot/schemas.py

@@ -0,0 +1,83 @@
+from pydantic import BaseModel, Field, computed_field
+from typing import Sequence, Optional
+import re
+
+class TaskPlanContext(BaseModel):
+    '''Background context relevant to the task plan'''
+    initial_context: str = Field(
+        min_length=1,
+        description="Background information about the database/tables and previous conversations relevant to the task.",
+    )
+    assumptions: Sequence[str] = Field(
+        description="Assumptions made while working on the task.",
+    )
+    constraints: Optional[Sequence[str]] = Field(
+        description="Constraints that apply to the task.",
+    )
+
+class TaskPlanResponse(BaseModel):
+    '''Structured plan to achieve the task objective'''
+    goal: str = Field(
+        min_length=1,
+        description="Single-sentence objective the plan must achieve.",
+    )
+    reflection: str = Field(
+        min_length=1,
+        description="High-level natural-language reasoning describing the user's request and the intended solution approach.",
+    )
+    context: TaskPlanContext = Field(
+        description="Background context relevant to the task plan.",
+    )
+    steps: Sequence[str] = Field(
+        min_length=1,
+        description="Ordered list of steps to execute that follow the 'Step <number>: <detail>' pattern.",
+    )
+
+_IM_SEP_TOKEN_PATTERN = re.compile(re.escape("<|im_sep|>"))
+_CODE_BLOCK_PATTERN = re.compile(r"```(?:python\s*)?(.*?)\s*```", re.DOTALL)
+_FORBIDDEN_MODULES = (
+    "subprocess",
+    "sys",
+    "eval",
+    "exec",
+    "socket",
+    "urllib",
+    "shutil",
+    "pickle",
+    "ctypes",
+    "multiprocessing",
+    "tempfile",
+    "glob",
+    "pty",
+    "commands",
+    "cgi",
+    "cgitb",
+    "xml.etree.ElementTree",
+    "builtins",
+)
+_FORBIDDEN_MODULE_PATTERN = re.compile(
+    r"^((?:[^#].*)?\b(" + "|".join(map(re.escape, _FORBIDDEN_MODULES)) + r")\b.*)$",
+    flags=re.MULTILINE,
+)
+
+class CodeGenerationResponse(BaseModel):
+    '''Code generation response structure'''
+    code: str = Field(description="The generated code snippet to accomplish the task")
+    explanation: str = Field(description="Explanation of the generated code and its functionality")
+
+    @computed_field(return_type=str)
+    @property
+    def parsed_code(self) -> str:
+        '''Extracts the code snippet without any surrounding text'''
+        normalised = _IM_SEP_TOKEN_PATTERN.sub("```", self.code).strip()
+        match = _CODE_BLOCK_PATTERN.search(normalised)
+        candidate = match.group(1).strip() if match else normalised
+        sanitised = _FORBIDDEN_MODULE_PATTERN.sub(r"# not allowed \1", candidate)
+        return sanitised.strip()
+    
+class RankResponse(BaseModel):
+    '''Code ranking response structure'''
+    rank: int = Field(
+        ge=1, le=10,
+        description="Rank of the code snippet from 1 (best) to 10 (worst)"
+    )