from fastapi import FastAPI, Request, BackgroundTasks
from fastapi.staticfiles import StaticFiles
import json
from processing_logic import run_email_processing

from fastapi.responses import FileResponse

app = FastAPI()

# Mount the 'web' directory to serve static files (CSS, JS)
app.mount("/static", StaticFiles(directory="web"), name="static")

@app.get("/")
def read_root():
    """Serves the main index.html file."""
    return FileResponse('web/index.html')

@app.get("/api/rules")
def get_rules():
    """Reads and returns the current rules from rules.json."""
    try:
        with open('rules.json', 'r', encoding='utf-8') as f:
            return json.load(f)
    except FileNotFoundError:
        return {"error": "rules.json not found"}
    except json.JSONDecodeError:
        return {"error": "Could not parse rules.json"}

@app.post("/api/rules")
async def save_rules(request: Request):
    """Receives new rules as JSON and overwrites rules.json."""
    try:
        new_rules = await request.json()
        with open('rules.json', 'w', encoding='utf-8') as f:
            json.dump(new_rules, f, indent=2, ensure_ascii=False)
        return {"message": "Rules saved successfully."}
    except json.JSONDecodeError:
        return {"error": "Invalid JSON format received."}
    except Exception as e:
        return {"error": f"An error occurred: {e}"}

@app.post("/api/run-processing")
async def trigger_processing(background_tasks: BackgroundTasks):
    """Triggers the email processing task in the background."""
    background_tasks.add_task(run_email_processing)
    return {"message": "Email processing task has been started in the background."}


if __name__ == "__main__":
    import uvicorn
    # This is for local development. For production, you'd run uvicorn directly.
    uvicorn.run(app, host="0.0.0.0", port=8000)