from fastapi import FastAPI, File, UploadFile, Form, HTTPException
from fastapi.responses import PlainTextResponse, FileResponse, HTMLResponse
from fastapi.requests import Request
from fastapi.staticfiles import StaticFiles
from fastapi.middleware.cors import CORSMiddleware
from typing import Optional
from starlette.exceptions import HTTPException as StarletteHTTPException

# Import your custom AI service
from services.client import generate_code_comments_and_docs

# ✅ Initialize FastAPI app
app = FastAPI()

# Add CORS middleware to allow cross-origin requests if needed
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# ✅ Mount the static folder so FastAPI can serve HTML, CSS, and JS files
app.mount("/static", StaticFiles(directory="static"), name="static")


# ✅ Serve the main frontend page
@app.get("/", response_class=HTMLResponse)
async def serve_index():
    return FileResponse("static/index.html")


# ✅ Main API route to handle code generation
@app.post("/generate-docs")
async def generate_docs(
    file: Optional[UploadFile] = File(None),
    code: Optional[str] = Form(None)
):
    try:
        # Check if neither file nor code was provided
        if not file and not code:
            raise HTTPException(status_code=400, detail="You must provide either a file or raw code.")

        # If raw text code is provided
        elif code:
            response = generate_code_comments_and_docs(code)
            return response
        
        # If a file is uploaded
        elif file:
            content = await file.read()
            code = content.decode("utf-8")
            response = generate_code_comments_and_docs(code)
            return response
        
        else:
            raise Exception("Invalid data")

    except Exception as ex:
        return PlainTextResponse(f"❌ Server error: {str(ex)}", status_code=500)


# ✅ Custom 404 Error Handler to serve your not-found.html
@app.exception_handler(StarletteHTTPException)
async def custom_404_handler(request: Request, exc: StarletteHTTPException):
    if exc.status_code == 404:
        return FileResponse("static/not-found.html")
    return PlainTextResponse(str(exc.detail), status_code=exc.status_code)