import os
import uuid
from datetime import datetime
from fastapi import FastAPI, UploadFile, File, Header, HTTPException, status, Form
from fastapi.middleware.cors import CORSMiddleware
from typing import Optional, List
from backend.services.openai_service import extract_receipt_data
from backend.schemas import ExtractionResponse, ClaimRecord, UserAccount, ClaimSubmission
from dotenv import load_dotenv

load_dotenv()

app = FastAPI(title="AI-Assisted Data Entry API")

# Configure CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # Adjust as needed for Angular frontend
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# In-memory database
CLAIMS_DB: List[ClaimRecord] = []
USERS_DB: List[UserAccount] = []

@app.get("/health")
async def health_check():
    return {"status": "healthy"}

@app.get("/api/v1/users", response_model=List[UserAccount])
async def get_users():
    return USERS_DB

@app.post("/api/v1/users", response_model=UserAccount)
async def create_user(user: UserAccount):
    USERS_DB.append(user)
    return user

@app.post("/api/v1/extract", response_model=ExtractionResponse)
async def extract_receipt(
    file: UploadFile = File(...),
    user_name: str = Form("Unknown Employee"),
    department: str = Form("Unknown Department")
):
    if not file.content_type.startswith("image/"):
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="File provided is not an image."
        )
    
    try:
        content = await file.read()
        extraction_result = await extract_receipt_data(content, user_name, department)
        
        if extraction_result is None:
             raise HTTPException(
                status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
                detail="Could not extract data from the provided image."
            )
            
        return extraction_result
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"An error occurred during extraction: {str(e)}"
        )

@app.post("/api/v1/claims", response_model=ClaimRecord)
async def submit_claim(
    submission_data: ClaimSubmission,
    user_id: str = Header(...)
):
    # 1. Find User
    user = next((u for u in USERS_DB if u.id == user_id), None)
    if not user:
        raise HTTPException(status_code=404, detail="User not found")

    # 2. Financial Guard Logic
    spent_amount = submission_data.amount_spent
    remaining = user.medical_allowance
    amount_claimed = min(spent_amount, remaining)

    # 3. Update User Balance
    user.medical_allowance -= amount_claimed

    # 4. Save Claim
    claim = ClaimRecord(
        id=str(uuid.uuid4()),
        timestamp=datetime.now().isoformat(),
        submitted_by=user.name,
        department=user.department,
        amount_spent=spent_amount,
        amount_claimed=amount_claimed,
        provider_name=submission_data.provider_name,
        visit_date=submission_data.visit_date,
        extraction_data=submission_data.extraction_data
    )
    CLAIMS_DB.append(claim)
    return claim

@app.get("/api/v1/claims", response_model=List[ClaimRecord])
async def get_claims():
    return CLAIMS_DB

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)