"""Gradio demo: PCB defect + golden reference -> enriched image (A11_CA prebackbone)."""

from __future__ import annotations

import os
import socket
from pathlib import Path

# HF Spaces: SSR needs Node and often serves unstyled HTML when it fails.
os.environ.setdefault("GRADIO_SSR_MODE", "false")

_ROOT = Path(__file__).resolve().parent


def _is_hf_space() -> bool:
    return bool(os.environ.get("SPACE_ID") or os.environ.get("SYSTEM") == "spaces")


def _configure_runtime() -> None:
    os.environ.setdefault(
        "PREBACKBONE_ONLY_WEIGHTS",
        str(_ROOT / "weights" / "prebackbone_a11_ca.pt"),
    )
    if _is_hf_space():
        os.environ.setdefault("PRELOAD_MODEL", "1")


_configure_runtime()

import gradio_patch

gradio_patch.apply()

import gradio as gr
import numpy as np
from PIL import Image

from prebackbone_infer import enrich_pair, get_enricher

TITLE = "RefDiffNet — PCB Reference–Defect Enrichment"
DESCRIPTION = """
Upload a **defect PCB image** and its **golden reference** (same H×W, pre-aligned — e.g. `*_input.jpg` / `*_reference.jpg` from training).
The RefDiffNet prebackbone outputs an **enriched** image: `enriched = defect + α · gate · delta`
"""


def run_demo(defect_path: str | None, reference_path: str | None):
    if not defect_path or not reference_path:
        raise gr.Error("Please upload both defect and reference images.")

    defect_rgb, ref_rgb, enriched_rgb = enrich_pair(defect_path, reference_path)
    defect_rgb = np.array(defect_rgb, dtype=np.uint8, copy=True)
    ref_rgb = np.array(ref_rgb, dtype=np.uint8, copy=True)
    enriched_rgb = np.array(enriched_rgb, dtype=np.uint8, copy=True)

    h = max(defect_rgb.shape[0], ref_rgb.shape[0], enriched_rgb.shape[0])

    def _pad(im: np.ndarray) -> np.ndarray:
        if im.shape[0] == h:
            return im
        pad = h - im.shape[0]
        return np.pad(im, ((0, pad), (0, 0), (0, 0)), mode="constant", constant_values=114)

    row = np.concatenate([_pad(defect_rgb), _pad(ref_rgb), _pad(enriched_rgb)], axis=1)
    return Image.fromarray(enriched_rgb), Image.fromarray(row)


def _example_pairs() -> list[list[str]]:
    """All *_input / *_reference pairs bundled in examples/ (from yolo26 prebackbone_samples)."""
    pairs: list[list[str]] = []
    ex_dir = _ROOT / "examples"
    if not ex_dir.is_dir():
        return pairs
    for inp in sorted(ex_dir.glob("*_input.jpg")):
        ref = inp.with_name(inp.name.replace("_input.", "_reference."))
        if ref.is_file():
            pairs.append([str(inp), str(ref)])
    return pairs


def _preload_model() -> None:
    try:
        get_enricher()
        print("[RefDiffNet] Prebackbone loaded.")
    except FileNotFoundError as e:
        print(f"[RefDiffNet] WARN: {e}")


def build_demo() -> gr.Interface:
    return gr.Interface(
        fn=run_demo,
        inputs=[
            gr.Image(type="filepath", label="Defect image (input)", height=320),
            gr.Image(type="filepath", label="Golden reference", height=320),
        ],
        outputs=[
            gr.Image(type="pil", label="Enriched output", height=360),
            gr.Image(type="pil", label="Defect | Reference | Enriched", height=360),
        ],
        title=TITLE,
        description=DESCRIPTION.strip(),
        examples=_example_pairs() or None,
        examples_per_page=6,
        cache_examples=False,
        flagging_mode="never",
        theme=gr.themes.Soft(),
    )


demo = build_demo()


def _local_launch_kwargs() -> dict:
    server_name = os.environ.get("GRADIO_SERVER_NAME", "127.0.0.1")
    preferred_port = int(os.environ.get("PORT", os.environ.get("GRADIO_SERVER_PORT", "7860")))
    bind_host = "127.0.0.1" if server_name in ("127.0.0.1", "localhost") else server_name
    server_port = preferred_port
    if server_name in ("127.0.0.1", "localhost"):
        for port in range(preferred_port, preferred_port + 20):
            with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
                sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
                try:
                    sock.bind((bind_host, port))
                    server_port = port
                    break
                except OSError:
                    continue
    share = os.environ.get("GRADIO_SHARE", "").lower() in ("1", "true", "yes")
    return {
        "server_name": server_name,
        "server_port": server_port,
        "share": share,
    }


def _launch() -> None:
    """Launch with SSR off (required for themed UI on HF Spaces)."""
    kwargs: dict = {"show_error": True, "ssr_mode": False}
    if _is_hf_space():
        demo.launch(**kwargs)
    else:
        demo.launch(
            **_local_launch_kwargs(),
            inbrowser=False,
            prevent_thread_lock=False,
            **kwargs,
        )


if __name__ == "__main__":
    print(f"[RefDiffNet] gradio {getattr(gr, '__version__', 'unknown')} ssr_mode=False")
    if os.environ.get("PRELOAD_MODEL", "0").lower() in ("1", "true", "yes"):
        _preload_model()
    _launch()