import os
import io
import base64
import json
import datetime
from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from google.oauth2.service_account import Credentials
from googleapiclient.discovery import build
from googleapiclient.http import MediaIoBaseUpload
import qrcode

app = FastAPI()

# Allow frontend (your InfinityFree domain) to call API
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # Restrict to your domain in production
    allow_methods=["*"],
    allow_headers=["*"],
)

# Load secrets from environment (set in Hugging Face Secrets)
SHEET_ID = os.getenv("GOOGLE_SHEET_ID")
FOLDER_ID = os.getenv("GOOGLE_DRIVE_FOLDER_ID")
SERVICE_ACCOUNT_INFO = json.loads(os.getenv("GOOGLE_SERVICE_ACCOUNT_JSON"))

def get_services():
    creds = Credentials.from_service_account_info(
        SERVICE_ACCOUNT_INFO,
        scopes=[
            "https://www.googleapis.com/auth/drive.file",
            "https://www.googleapis.com/auth/spreadsheets"
        ]
    )
    drive = build("drive", "v3", credentials=creds)
    sheets = build("sheets", "v4", credentials=creds)
    return drive, sheets

class CertRequest(BaseModel):
    pdfBase64: str      # base64 encoded PDF
    fileName: str       # e.g., "John_Doe_certificate.pdf"
    name: str
    email: str = ""     # optional, for future
    code: str           # 9-character verification code

@app.post("/api/upload-certificate")
async def upload_certificate(req: CertRequest):
    try:
        drive, sheets = get_services()

        # Decode PDF
        pdf_bytes = base64.b64decode(req.pdfBase64)
        media = MediaIoBaseUpload(io.BytesIO(pdf_bytes), mimetype='application/pdf', resumable=False)

        # Upload to Drive
        file = drive.files().create(
            body={'name': req.fileName, 'parents': [FOLDER_ID]},
            media_body=media,
            fields='id,webViewLink'
        ).execute()

        # Make it publicly viewable (anyone with link can view)
        drive.permissions().create(
            fileId=file['id'],
            body={'type': 'anyone', 'role': 'reader'}
        ).execute()

        # Append record to Google Sheet
        now = datetime.datetime.now().isoformat()
        values = [[
            now,
            req.name,
            req.email,
            req.code,
            file['id'],
            file['webViewLink'],
            'active'
        ]]
        sheets.spreadsheets().values().append(
            spreadsheetId=SHEET_ID,
            range='Certificates!A:G',  # Assumes headers in row 1
            valueInputOption='USER_ENTERED',
            body={'values': values}
        ).execute()

        return {"success": True, "fileUrl": file['webViewLink']}

    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

@app.get("/api/verify/{code}")
async def verify(code: str):
    try:
        _, sheets = get_services()
        result = sheets.spreadsheets().values().get(
            spreadsheetId=SHEET_ID,
            range='Certificates!A:G'
        ).execute()
        rows = result.get('values', [])
        # Skip header row
        for row in rows[1:]:
            if len(row) >= 4 and row[3] == code:
                return {
                    "valid": True,
                    "name": row[1],
                    "date": row[0],
                    "fileUrl": row[5]
                }
        return {"valid": False}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

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