# app.py (Python_ai)
import difflib
import json
import os
from typing import Dict, Any

from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse
from fastapi.middleware.cors import CORSMiddleware

APP_NAME = "Python_ai"
app = FastAPI(title=APP_NAME)

# Allow CORS just in case you call it directly from the Brain UI
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"], allow_credentials=True,
    allow_methods=[""], allow_headers=[""],
)

def ok(payload: Dict[str, Any] | None = None) -> JSONResponse:
    return JSONResponse({"ok": True, **(payload or {})})

@app.get("/health")
def health():
    return ok()

def make_unified_diff(filename: str, old_text: str, new_text: str) -> str:
    # Ensure both end with newline so ranges are sane
    if not old_text.endswith("\n"): old_text += "\n"
    if not new_text.endswith("\n"): new_text += "\n"
    diff = difflib.unified_diff(
        old_text.splitlines(keepends=True),
        new_text.splitlines(keepends=True),
        fromfile=f"a/{filename}",
        tofile=f"b/{filename}",
        n=3,
    )
    return "".join(diff)

def minimal_fix(view_text: str) -> tuple[str, str, str]:
    """
    Very small heuristic fixer:
    - reslt -> result (common typo)
    - NameError 'bar' if foo returns bar but bar undefined -> return 'result' instead
    Only edits when the change is obvious; otherwise returns original text.
    """
    old = view_text
    new = old

    # Trivial typo fix
    if "reslt" in new:
        new = new.replace("reslt", "result")

    # If there's a pattern like:
    # def foo():\n    return bar\n\nresult = foo()
    # we can't know bar; safer to leave it alone here.
    # Keep this service minimal/fast.

    return old, new, "Fixed trivial misspelling(s) where obvious."

@app.post("/code_help")
async def code_help(req: Request):
    """
    Accepts ANY JSON shape to avoid 422. We only read fields we need.
    Returns a PATCH-first JSON as your 'PythonFixer' contract expects.
    """
    try:
        body = await req.json()
    except Exception:
        body = {}

    # Extract with defaults (never 422)
    utterance = body.get("utterance", "")
    telemetry = body.get("telemetry", {}) or {}
    filename = telemetry.get("file", "main.py")
    viewport = telemetry.get("viewport", {}) or {}
    view_text = viewport.get("text", "")

    # Minimal edit logic
    old_text, new_text, why = minimal_fix(view_text)

    if new_text != old_text:
        patch = make_unified_diff(filename, old_text, new_text)
        resp = {
            "mode": "patch",
            "patch": patch,
            "full_text": "",
            "explanation": why,
            "confidence": 0.96,
            "need": {"function": False, "xrefs": [], "page_ids": []},
        }
    else:
        # Nothing obvious to fix; ask for more context (keeps contract)
        resp = {
            "mode": "ask",
            "patch": "",
            "full_text": "",
            "explanation": "Need more context or a specific error message to propose a safe minimal patch.",
            "confidence": 0.55,
            "need": {"function": False, "xrefs": [], "page_ids": []},
        }

    # Always 200 with the contract object
    return JSONResponse(resp)

# HF entry
if _name_ == "_main_":
    import uvicorn
    uvicorn.run("app:app", host="0.0.0.0", port=int(os.getenv("PORT", "7860")), reload=False)