"""
VM Bench — Proxmox Image Conversion Frontend

FastAPI web application serving as the user GUI.
Runs in the vm-bench LXC on port 5000.
Communicates with the backend at http://10.2.0.2:9000.

Routes:
  GET  /                       New session form
  POST /session/start           Upload + analyse source image
  POST /session/confirm         Submit conversion job
  GET  /session/status/{id}     Poll job status (JSON)
  POST /session/cleanup/{id}    Clean up / reuse staging files
"""

from __future__ import annotations

import os
import shutil
import subprocess
import uuid
from pathlib import Path
from typing import Optional

from fastapi import FastAPI, Form, Request, UploadFile, File
from fastapi.responses import HTMLResponse, JSONResponse
from fastapi.staticfiles import StaticFiles

from jinja2 import Environment, FileSystemLoader

from api_client import ApiClient, ApiError, BACKEND_URL

# ---------------------------------------------------------------------------
# App setup
# ---------------------------------------------------------------------------
app = FastAPI(title="VM Bench — Frontend", version="1.0.0")

BASE = Path(__file__).parent
app.mount("/static", StaticFiles(directory=str(BASE / "static")), name="static")

_jinja = Environment(loader=FileSystemLoader(str(BASE / "templates")), autoescape=True)
STAGING = Path("/mnt/converter/in")

api = ApiClient()

# Config
VM_ID_MIN = 21000
VM_ID_MAX = 21100
DEFAULT_STORAGE = "local-lvm"

def _validate_vmid(vmid: int) -> Optional[str]:
    if not (VM_ID_MIN <= vmid <= VM_ID_MAX):
        return f"VM ID must be between {VM_ID_MIN} and {VM_ID_MAX}."
    return None

def render(name: str, status: int = 200, **ctx) -> HTMLResponse:
    tpl = _jinja.get_template(name)
    return HTMLResponse(tpl.render(**ctx), status_code=status)


# ---------------------------------------------------------------------------
# Routes
# ---------------------------------------------------------------------------

@app.get("/", response_class=HTMLResponse)
async def index(request: Request, vmid: Optional[int] = None, source: Optional[str] = None):
    """Landing page — new session form. Optionally pre-fills vmid + source for reuse."""
    return render("index.html", request=request, backend_url=BACKEND_URL,
                  prefill_vmid=vmid or "", prefill_source=source or "")


@app.post("/session/start", response_class=HTMLResponse)
async def start_session(
    request: Request,
    vmid: int = Form(...),
    source_type: str = Form("upload"),
    source_file: Optional[UploadFile] = File(None),
    source_url: Optional[str] = Form(None),
):
    """Upload or download source file, then call backend /analyze."""
    filename = None
    error = None

    # Validate VM ID range
    err = _validate_vmid(vmid)
    if err:
        return render("_analysis.html", request=request, error=err)

    # --- Get the file into /mnt/converter/in/ ---
    if source_type == "upload":
        if not source_file or not source_file.filename:
            error = "No file uploaded."
        else:
            filename = source_file.filename
            dest = STAGING / filename
            try:
                with dest.open("wb") as f:
                    shutil.copyfileobj(source_file.file, f)
            except Exception as exc:
                error = f"Upload failed: {exc}"
    else:
        url = (source_url or "").strip()
        if not url:
            error = "No URL provided."
        else:
            filename = Path(url).name or f"download_{uuid.uuid4().hex[:8]}"
            dest = STAGING / filename
            try:
                result = subprocess.run(
                    ["wget", "-q", "--show-progress", "-O", str(dest), url],
                    capture_output=True, text=True, timeout=1800,
                )
                if result.returncode != 0:
                    error = f"Download failed: {result.stderr.strip()[:300]}"
            except subprocess.TimeoutExpired:
                error = "Download timed out (30 min limit)."
            except Exception as exc:
                error = f"Download failed: {exc}"

    if error:
        return render("_analysis.html", request=request, error=error)

    # --- Call backend /analyze ---
    try:
        analysis = api.analyze(vmid=vmid, filename=filename)
    except ApiError as exc:
        return render("_analysis.html", request=request,
                      error=f"Backend analysis failed: {exc.detail}")

    vm_name = (analysis.get("os_type") or "vm") + f"-{vmid}"

    return render("_analysis.html", request=request,
                  vmid=vmid, source_filename=filename,
                  vm_name=vm_name, analysis=analysis)


@app.post("/session/confirm", response_class=HTMLResponse)
async def confirm_session(
    request: Request,
    vmid: int = Form(...),
    source_filename: str = Form(...),
    disk_format: str = Form(...),
    vm_name: str = Form(...),
    cpu_cores: int = Form(2),
    ram_mb: int = Form(4096),
    target_storage: str = Form("local-lvm"),
    target_disk_size_gb: Optional[int] = Form(None),
    auto_detect_boot: str = Form("true"),
    boot_type: str = Form("uefi"),
):
    """Build the job payload and submit to the backend."""
    # Validate VM ID range
    err = _validate_vmid(vmid)
    if err:
        return render("_analysis.html", request=request, error=err)

    payload = {
        "vmid": vmid,
        "vm_name": vm_name,
        "cpu_cores": cpu_cores,
        "ram_mb": ram_mb,
        "target_storage": target_storage,
        "auto_detect_boot": auto_detect_boot == "true",
        "boot_type": boot_type,
        "boot_disk": {
            "disk_type": "image_file",
            "source_filename": source_filename,
            "format": disk_format,
        },
    }
    if target_disk_size_gb is not None:
        payload["target_disk_size_gb"] = target_disk_size_gb

    try:
        job = api.create_job(payload)
    except ApiError as exc:
        return render("_analysis.html", request=request,
                      error=f"Job submission failed: {exc.detail}")

    return render("polling.html", request=request,
                  job_id=job["job_id"], vmid=vmid,
                  vm_name=vm_name, source_filename=source_filename)


@app.get("/session/status/{job_id}")
async def session_status(job_id: str):
    """Poll backend for job status (returns JSON for AJAX polling)."""
    try:
        return api.get_job(job_id)
    except ApiError as exc:
        return JSONResponse({"error": exc.detail, "status": "error"}, status_code=502)


@app.post("/session/cleanup/{job_id}")
async def session_cleanup(job_id: str, request: Request):
    """Forward cleanup request to backend."""
    try:
        body = await request.json()
        delete = body.get("delete_staging_files", False)
        return api.cleanup_job(job_id, delete)
    except ApiError as exc:
        return JSONResponse({"error": exc.detail}, status_code=502)


# ---------------------------------------------------------------------------
# Run
# ---------------------------------------------------------------------------
if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=5000)