import os
import shutil
from fastapi import FastAPI, Request, File, UploadFile, Form
from fastapi.responses import HTMLResponse, RedirectResponse
from fastapi.templating import Jinja2Templates
from fastapi.staticfiles import StaticFiles

# =====================================================================
# MODIFICATION: ROOT PATH FOR NGINX
# Why: When Nginx routes traffic from yourdomain.com/patch-manager/ 
# to this sidecar, FastAPI needs to know its "base" URL is no longer "/".
# If we don't set this, the app will try to load CSS and submit forms 
# to the wrong root URL, resulting in 404 errors.
# =====================================================================
app = FastAPI(root_path="/patch-manager")

app.mount("/static", StaticFiles(directory="static"), name="static")
templates = Jinja2Templates(directory="templates")

OVERLAY_DIR = "/srv"

@app.get("/", response_class=HTMLResponse)
async def index(request: Request):
    files = []
    if os.path.exists(OVERLAY_DIR):
        for root, dirs, filenames in os.walk(OVERLAY_DIR):
            for filename in filenames:
                rel_path = os.path.relpath(os.path.join(root, filename), OVERLAY_DIR)
                files.append(rel_path)
    return templates.TemplateResponse("index.html", {"request": request, "files": sorted(files)})

@app.post("/upload")
async def upload_file(file: UploadFile = File(...), target_path: str = Form("")):
    save_dir = os.path.join(OVERLAY_DIR, target_path.strip("/"))
    os.makedirs(save_dir, exist_ok=True)
    file_location = os.path.join(save_dir, file.filename)
    with open(file_location, "wb+") as file_object:
        shutil.copyfileobj(file.file, file_object)
    
    # Notice we redirect to "/" here. Because we set root_path="/patch-manager",
    # FastAPI automatically translates this redirect to "/patch-manager/"!
    return RedirectResponse(url="/", status_code=303)

@app.post("/delete")
async def delete_file(filepath: str = Form(...)):
    target = os.path.join(OVERLAY_DIR, filepath)
    if os.path.exists(target):
        os.remove(target)
        target_dir = os.path.dirname(target)
        if not os.listdir(target_dir) and target_dir != OVERLAY_DIR:
            os.rmdir(target_dir)
    return RedirectResponse(url="/", status_code=303)

@app.get("/edit", response_class=HTMLResponse)
async def edit_file(request: Request, filepath: str):
    target = os.path.join(OVERLAY_DIR, filepath)
    content = ""
    if os.path.exists(target):
        with open(target, "r", encoding="utf-8", errors="ignore") as f:
            content = f.read()
    return templates.TemplateResponse("edit.html", {"request": request, "filepath": filepath, "content": content})

@app.post("/edit")
async def save_file(filepath: str = Form(...), content: str = Form(...)):
    target = os.path.join(OVERLAY_DIR, filepath)
    if os.path.exists(target):
        with open(target, "w", encoding="utf-8") as f:
            f.write(content)
    return RedirectResponse(url="/", status_code=303)