from fastapi import FastAPI, File, UploadFile, Depends, HTTPException, Security
from fastapi.responses import FileResponse, PlainTextResponse
from fastapi.security import APIKeyHeader
from sqlalchemy import exists
import hashlib
from . import db
from dotenv import load_dotenv
import os

load_dotenv()

FILES_DIR = os.getenv("FILES_DIR")
API_KEY = os.getenv("API_KEY")
api_key_header = APIKeyHeader(name="X-API-Key")

def verify_api_key(api_key: str = Security(api_key_header)):
    if api_key != API_KEY:
        raise HTTPException(status_code=403, detail="Forbidden")
    return api_key

def compute_hash(data: bytes, algorithm="sha256") -> str:
    h = hashlib.new(algorithm)
    h.update(data)
    return h.hexdigest()

app = FastAPI()


@app.get("/")
async def root():
    return {"message": "hiii from sfs"}

@app.post("/file")
async def save_file(file: UploadFile = File(...), api_key: str = Depends(verify_api_key)):
    contents = await file.read()
    
    hash = compute_hash(contents)

    existed_url = db.file_exists(file.size, hash)

    if not existed_url:
        file_url = db.add_file(file.filename, file.content_type, file.size, hash)
    
        try:
            with open(f"{FILES_DIR}/{file_url}", "wb") as f:
                f.write(contents)
            return {"status": "saved", "filename": file_url}
        except Exception as e:
            db.remove_file(file_url)
            return {"status": "error", "message": f"Could not save file {file_url}: {e}"}
    else:
        return {"status": "file_exists", "filename": existed_url}

@app.get("/file/{filename}")
async def get_file(filename: str, raw: bool = False, api_key: str = Depends(verify_api_key)):
    file_path = os.path.join(FILES_DIR, filename)

    if not os.path.exists(file_path):
        raise HTTPException(status_code=404, detail="File not found")
    if raw:
        with open(file_path, "r", encoding="utf-8", errors="ignore") as f:
            return PlainTextResponse(f.read())

    return FileResponse(file_path, filename=filename)


@app.delete("/file/{filename}")
async def delete_file(filename: str, api_key: str = Depends(verify_api_key)):
    if db.remove_file(filename):
        file_path = f"{FILES_DIR}/{filename}"
        if os.path.exists(file_path):
            os.remove(file_path)
        return {"status": "deleted"}
    return {"status": "error", "message": "no file like that"}

@app.get("/files/")
async def get_list_of_files(api_key: str = Depends(verify_api_key)):
    files = db.get_all_files()
    return [
        {
            "id": f.id,
            "name": f.name,
            "content_type": f.content_type,
            "size": f.size,
            "hash": f.hash,
        }
        for f in files
    ]

@app.get("/healthchecker")
async def healthchecker(api_key: str = Depends(verify_api_key)):
    return {"message": "Howdy :3"}