"""视角变换服务 — 调用 Zero123++ 等模型，将单张图片转为多视角图片。"""

import base64
import logging
import mimetypes
import os
import uuid
from pathlib import Path
from typing import Any

import httpx
from PIL import Image

from app.config import get_view_transform_model_config
from app.services.image_gen import _make_replicate_client, GENERATED_DIR, to_data_uri

logger = logging.getLogger(__name__)

_replicate_client = _make_replicate_client()


def _split_grid_image(
    image_path: Path,
    cols: int,
    rows: int,
    view_labels: list[dict[str, int]],
) -> list[dict[str, Any]]:
    """将 Zero123++ 输出的 grid 拼接图切分为独立的视角图片。

    返回格式：[{"url": "/generated/xxx.png", "azimuth": 30, "elevation": 30}, ...]
    Grid 布局从左到右、从上到下依次对应 view_labels 中的视角。
    """
    img = Image.open(image_path)
    w, h = img.size
    cell_w = w // cols
    cell_h = h // rows

    results: list[dict[str, Any]] = []
    for idx, view in enumerate(view_labels):
        row_idx = idx // cols
        col_idx = idx % cols
        left = col_idx * cell_w
        upper = row_idx * cell_h
        right = left + cell_w
        lower = upper + cell_h

        cropped = img.crop((left, upper, right, lower))
        filename = f"view_{uuid.uuid4().hex[:8]}_az{view['azimuth']}_el{view['elevation']}.png"
        filepath = GENERATED_DIR / filename
        cropped.save(filepath, "PNG")

        results.append({
            "url": f"/generated/{filename}",
            "azimuth": view["azimuth"],
            "elevation": view["elevation"],
        })

    return results


async def _download_to_local(url: str) -> Path:
    """下载远程图片到本地 generated/ 目录，返回本地路径。"""
    filename = f"grid_{uuid.uuid4().hex}.png"
    filepath = GENERATED_DIR / filename
    proxy = os.environ.get("HTTPS_PROXY") or os.environ.get("HTTP_PROXY")
    async with httpx.AsyncClient(proxy=proxy, timeout=httpx.Timeout(120.0)) as client:
        resp = await client.get(url, follow_redirects=True)
        resp.raise_for_status()
        filepath.write_bytes(resp.content)
    return filepath


async def transform_view(
    image_path: str,
    model_id: str | None = None,
) -> dict[str, Any]:
    """调用视角变换模型，返回多视角图片列表。

    Args:
        image_path: 输入图片路径（本地路径、data URI 或 URL）
        model_id: 视角变换模型 ID，默认 zero123plus

    Returns:
        {
            "success": bool,
            "images": [{"url": str, "azimuth": int, "elevation": int}, ...],
            "grid_image": str,  # 原始拼接图的本地 URL
            "model_name": str,
            "error": str | None,
        }
    """
    config = get_view_transform_model_config(model_id)
    model_name = config["name"]
    replicate_model_id = config["model_id"]
    grid_layout = config["grid_layout"]
    output_views = config["output_views"]

    GENERATED_DIR.mkdir(parents=True, exist_ok=True)

    try:
        image_uri = to_data_uri(image_path)
        input_params = {"image": image_uri}

        logger.info("调用 %s 进行视角变换...", model_name)
        output = await _replicate_client.async_run(
            replicate_model_id, input=input_params, wait=False
        )

        # Zero123++ 返回单张 grid 拼接图
        items = output if isinstance(output, list) else [output]
        if not items:
            return {
                "success": False,
                "images": [],
                "grid_image": None,
                "model_name": model_name,
                "error": "模型未返回任何输出",
            }

        grid_url = str(items[0])
        if not (grid_url.startswith("http://") or grid_url.startswith("https://")):
            return {
                "success": False,
                "images": [],
                "grid_image": None,
                "model_name": model_name,
                "error": f"模型返回非图片内容: {grid_url[:200]}",
            }

        grid_local_path = await _download_to_local(grid_url)
        grid_local_url = f"/generated/{grid_local_path.name}"

        view_images = _split_grid_image(
            grid_local_path,
            cols=grid_layout["cols"],
            rows=grid_layout["rows"],
            view_labels=output_views,
        )

        return {
            "success": True,
            "images": view_images,
            "grid_image": grid_local_url,
            "model_name": model_name,
            "error": None,
        }

    except Exception as e:
        detail = str(e) or f"{type(e).__name__}: {repr(e)}"
        logger.error("视角变换失败: %s", detail, exc_info=True)
        return {
            "success": False,
            "images": [],
            "grid_image": None,
            "model_name": model_name,
            "error": detail,
        }