import os
import subprocess
import sys
import math

# Disable torch.compile / dynamo before any torch import
os.environ["TORCH_COMPILE_DISABLE"] = "1"
os.environ["TORCHDYNAMO_DISABLE"] = "1"

# Install xformers for memory-efficient attention
subprocess.run(
    [sys.executable, "-m", "pip", "install", "xformers==0.0.32.post2", "--no-build-isolation"],
    check=False
)

# Clone LTX-2 repo and install packages
LTX_REPO_URL = "https://github.com/Lightricks/LTX-2.git"
LTX_REPO_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "LTX-2")

if not os.path.exists(LTX_REPO_DIR):
    print(f"Cloning {LTX_REPO_URL}...")
    subprocess.run(["git", "clone", "--depth", "1", LTX_REPO_URL, LTX_REPO_DIR], check=True)

print("Installing ltx-core and ltx-pipelines from cloned repo...")
subprocess.run(
    [
        sys.executable, "-m", "pip", "install", "--force-reinstall", "--no-deps", "-e",
        os.path.join(LTX_REPO_DIR, "packages", "ltx-core"),
        "-e", os.path.join(LTX_REPO_DIR, "packages", "ltx-pipelines")
    ],
    check=True,
)

sys.path.insert(0, os.path.join(LTX_REPO_DIR, "packages", "ltx-pipelines", "src"))
sys.path.insert(0, os.path.join(LTX_REPO_DIR, "packages", "ltx-core", "src"))

import logging
import random
import tempfile
from pathlib import Path

import torch
torch._dynamo.config.suppress_errors = True
torch._dynamo.config.disable = True

import spaces
import gradio as gr
import numpy as np
from huggingface_hub import hf_hub_download, snapshot_download

from ltx_core.model.video_vae import TilingConfig, get_video_chunks_number
from ltx_core.quantization import QuantizationPolicy
from ltx_pipelines.distilled import DistilledPipeline
from ltx_pipelines.utils.args import ImageConditioningInput
from ltx_pipelines.utils.media_io import encode_video

# Force-patch xformers attention into the LTX attention module.
from ltx_core.model.transformer import attention as _attn_mod
print(f"[ATTN] Before patch: memory_efficient_attention={_attn_mod.memory_efficient_attention}")
try:
    from xformers.ops import memory_efficient_attention as _mea
    _attn_mod.memory_efficient_attention = _mea
    print(f"[ATTN] After patch: memory_efficient_attention={_attn_mod.memory_efficient_attention}")
except Exception as e:
    print(f"[ATTN] xformers patch FAILED: {type(e).__name__}: {e}")

logging.getLogger().setLevel(logging.INFO)

MAX_SEED = np.iinfo(np.int32).max
DEFAULT_FRAME_RATE = 24.0

# LTX-2.3 官方单次最长 20 秒
MAX_DURATION_SECONDS = 20.0

# 为了降低 20 秒长视频时的失败率，做一个长视频阈值
LONG_VIDEO_THRESHOLD = 10.0

# Resolution presets: (width, height)
RESOLUTIONS = {
    "high": {
        "16:9": (1536, 1024),
        "9:16": (1024, 1536),
        "1:1": (1024, 1024),
    },
    "low": {
        "16:9": (768, 512),
        "9:16": (512, 768),
        "1:1": (768, 768),
    },
}

# Model repos
LTX_MODEL_REPO = "Lightricks/LTX-2.3"
GEMMA_REPO = "google/gemma-3-12b-it-qat-q4_0-unquantized"

print("=" * 80)
print("Downloading LTX-2.3 distilled model + Gemma...")
print("=" * 80)

checkpoint_path = hf_hub_download(
    repo_id=LTX_MODEL_REPO,
    filename="ltx-2.3-22b-distilled.safetensors"
)
spatial_upsampler_path = hf_hub_download(
    repo_id=LTX_MODEL_REPO,
    filename="ltx-2.3-spatial-upscaler-x2-1.0.safetensors"
)
gemma_root = snapshot_download(repo_id=GEMMA_REPO)

print(f"Checkpoint: {checkpoint_path}")
print(f"Spatial upsampler: {spatial_upsampler_path}")
print(f"Gemma root: {gemma_root}")

# Initialize pipeline WITH text encoder
pipeline = DistilledPipeline(
    distilled_checkpoint_path=checkpoint_path,
    spatial_upsampler_path=spatial_upsampler_path,
    gemma_root=gemma_root,
    loras=[],
    quantization=QuantizationPolicy.fp8_cast(),
)

# Preload all models for ZeroGPU tensor packing.
print("Preloading all models (including Gemma)...")
ledger = pipeline.model_ledger
_transformer = ledger.transformer()
_video_encoder = ledger.video_encoder()
_video_decoder = ledger.video_decoder()
_audio_decoder = ledger.audio_decoder()
_vocoder = ledger.vocoder()
_spatial_upsampler = ledger.spatial_upsampler()
_text_encoder = ledger.text_encoder()
_embeddings_processor = ledger.gemma_embeddings_processor()

ledger.transformer = lambda: _transformer
ledger.video_encoder = lambda: _video_encoder
ledger.video_decoder = lambda: _video_decoder
ledger.audio_decoder = lambda: _audio_decoder
ledger.vocoder = lambda: _vocoder
ledger.spatial_upsampler = lambda: _spatial_upsampler
ledger.text_encoder = lambda: _text_encoder
ledger.gemma_embeddings_processor = lambda: _embeddings_processor
print("All models preloaded (including Gemma text encoder)!")

print("=" * 80)
print("Pipeline ready!")
print("=" * 80)


def log_memory(tag: str):
    """打印显存信息，便于排查长视频生成问题。"""
    if torch.cuda.is_available():
        allocated = torch.cuda.memory_allocated() / 1024**3
        peak = torch.cuda.max_memory_allocated() / 1024**3
        free, total = torch.cuda.mem_get_info()
        print(
            f"[VRAM {tag}] "
            f"allocated={allocated:.2f}GB "
            f"peak={peak:.2f}GB "
            f"free={free / 1024**3:.2f}GB "
            f"total={total / 1024**3:.2f}GB"
        )


def detect_aspect_ratio(image) -> str:
    """根据输入图像自动匹配最接近的宽高比。"""
    if image is None:
        return "16:9"

    if hasattr(image, "size"):
        w, h = image.size
    elif hasattr(image, "shape"):
        h, w = image.shape[:2]
    else:
        return "16:9"

    ratio = w / h
    candidates = {
        "16:9": 16 / 9,
        "9:16": 9 / 16,
        "1:1": 1.0,
    }
    return min(candidates, key=lambda k: abs(ratio - candidates[k]))


def get_resolution_by_state(image, high_res: bool, duration: float):
    """
    根据图片比例、分辨率开关、时长，返回最终建议分辨率。
    为了让 20 秒视频更稳定，长视频强制降到 low preset。
    """
    aspect = detect_aspect_ratio(image)

    # 10秒以上统一走 low，显著降低 OOM 和超时概率
    if duration > LONG_VIDEO_THRESHOLD:
        tier = "low"
    else:
        tier = "high" if high_res else "low"

    w, h = RESOLUTIONS[tier][aspect]
    return w, h, tier, aspect


def on_image_upload(image, high_res, duration):
    """上传图片后，自动设置分辨率。"""
    w, h, tier, aspect = get_resolution_by_state(image, bool(high_res), float(duration))
    tip = f"已自动匹配比例 {aspect}，当前使用 {tier} 分辨率：{w}×{h}"
    return gr.update(value=w), gr.update(value=h), gr.update(value=tip)


def on_highres_toggle(image, high_res, duration):
    """切换高分辨率开关时，联动分辨率。"""
    w, h, tier, aspect = get_resolution_by_state(image, bool(high_res), float(duration))
    if float(duration) > LONG_VIDEO_THRESHOLD and bool(high_res):
        tip = f"当前时长 {duration:.1f}s，已为稳定性自动降为 low 分辨率：{w}×{h}"
    else:
        tip = f"已自动匹配比例 {aspect}，当前使用 {tier} 分辨率：{w}×{h}"
    return gr.update(value=w), gr.update(value=h), gr.update(value=tip)


def on_duration_change(image, high_res, duration):
    """切换时长时，也同步调整分辨率策略。"""
    w, h, tier, aspect = get_resolution_by_state(image, bool(high_res), float(duration))
    if float(duration) > LONG_VIDEO_THRESHOLD:
        tip = (
            f"当前时长 {duration:.1f}s，已自动切换到 low 分辨率 {w}×{h}，"
            f"以降低显存占用和超时风险。"
        )
    else:
        tip = f"当前时长 {duration:.1f}s，比例 {aspect}，使用 {tier} 分辨率：{w}×{h}"
    return gr.update(value=w), gr.update(value=h), gr.update(value=tip)


def clamp_int(v, min_v, max_v):
    """整数安全钳制。"""
    return max(min_v, min(int(v), max_v))


def align_num_frames(duration: float, frame_rate: float) -> int:
    """
    将帧数对齐到 LTX 常用的 8n+1 形式。
    例如：
    20秒 * 24fps = 480 帧
    对齐后为 481 帧
    """
    raw_frames = int(duration * frame_rate) + 1
    aligned_frames = ((raw_frames - 1 + 7) // 8) * 8 + 1
    return aligned_frames


# 20 秒视频推理时间明显更长，因此把 GPU duration 提高
@spaces.GPU(duration=240)
@torch.inference_mode()
def generate_video(
    input_image,
    prompt: str,
    duration: float,
    enhance_prompt: bool = True,
    seed: int = 42,
    randomize_seed: bool = True,
    height: int = 1024,
    width: int = 1536,
    high_res: bool = True,
    progress=gr.Progress(track_tqdm=True),
):
    current_seed = random.randint(0, MAX_SEED) if randomize_seed else int(seed)

    try:
        torch.cuda.reset_peak_memory_stats()
        log_memory("start")

        # ---------- 参数安全限制 ----------
        duration = max(1.0, min(float(duration), MAX_DURATION_SECONDS))
        frame_rate = DEFAULT_FRAME_RATE
        num_frames = align_num_frames(duration, frame_rate)

        # 宽高做整数与边界保护
        width = clamp_int(width, 256, 2048)
        height = clamp_int(height, 256, 2048)

        # 长视频时自动降级分辨率，提高成功率
        safe_w, safe_h, safe_tier, safe_aspect = get_resolution_by_state(input_image, bool(high_res), duration)
        if duration > LONG_VIDEO_THRESHOLD:
            if width != safe_w or height != safe_h:
                print(
                    f"[SAFE] Long video detected ({duration:.1f}s). "
                    f"Override resolution from {width}x{height} to {safe_w}x{safe_h}"
                )
            width, height = safe_w, safe_h

        print(
            f"Generating: {height}x{width}, "
            f"{num_frames} frames ({duration:.1f}s), "
            f"seed={current_seed}, high_res={high_res}, safe_tier={safe_tier}"
        )

        images = []
        if input_image is not None:
            output_dir = Path("outputs")
            output_dir.mkdir(exist_ok=True)
            temp_image_path = output_dir / f"temp_input_{current_seed}.jpg"

            if hasattr(input_image, "save"):
                input_image.save(temp_image_path)
            else:
                temp_image_path = Path(input_image)

            images = [
                ImageConditioningInput(
                    path=str(temp_image_path),
                    frame_idx=0,
                    strength=1.0
                )
            ]

        tiling_config = TilingConfig.default()
        video_chunks_number = get_video_chunks_number(num_frames, tiling_config)

        log_memory("before pipeline call")

        video, audio = pipeline(
            prompt=prompt,
            seed=current_seed,
            height=int(height),
            width=int(width),
            num_frames=num_frames,
            frame_rate=frame_rate,
            images=images,
            tiling_config=tiling_config,
            enhance_prompt=bool(enhance_prompt),
        )

        log_memory("after pipeline call")

        output_path = tempfile.mktemp(suffix=".mp4")
        encode_video(
            video=video,
            fps=frame_rate,
            audio=audio,
            output_path=output_path,
            video_chunks_number=video_chunks_number,
        )

        log_memory("after encode_video")
        return str(output_path), current_seed, (
            f"生成成功：{duration:.1f} 秒，{num_frames} 帧，输出分辨率 {width}×{height}"
        )

    except Exception as e:
        import traceback
        log_memory("on error")
        err = f"{type(e).__name__}: {str(e)}"
        print(f"Error: {err}\n{traceback.format_exc()}")

        user_msg = (
            "生成失败。\n"
            f"错误：{err}\n\n"
            "建议：\n"
            "1. 20秒视频请优先使用低分辨率\n"
            "2. 先关闭 High Resolution\n"
            "3. 输入图尽量简单，减少复杂运动\n"
            "4. 如在 ZeroGPU / Hugging Face Space 上运行，长视频可能仍会因排队或时限失败"
        )
        return None, current_seed, user_msg


with gr.Blocks(title="LTX-2.3 Distilled") as demo:
    gr.Markdown("# LTX-2.3 Distilled (22B): Fast Audio-Video Generation")
    gr.Markdown(
        "Fast and high quality video + audio generation  \n"
        "[[model]](https://huggingface.co/Lightricks/LTX-2.3) "
        "[[code]](https://github.com/Lightricks/LTX-2)"
    )
    gr.Markdown(
        "说明：已支持最长 20 秒视频。为提高成功率，超过 10 秒时会自动切换为低分辨率。"
    )

    with gr.Row():
        with gr.Column():
            input_image = gr.Image(label="Input Image (Optional)", type="pil")

            prompt = gr.Textbox(
                label="Prompt",
                info="for best results - make it as elaborate as possible",
                value="Make this image come alive with cinematic motion, smooth animation",
                lines=3,
                placeholder="Describe the motion and animation you want...",
            )

            with gr.Row():
                duration = gr.Slider(
                    label="Duration (seconds)",
                    minimum=1.0,
                    maximum=20.0,   # 改为 20 秒
                    value=3.0,
                    step=0.1
                )
                with gr.Column():
                    enhance_prompt = gr.Checkbox(label="Enhance Prompt", value=False)
                    high_res = gr.Checkbox(label="High Resolution", value=True)

            generate_btn = gr.Button("Generate Video", variant="primary", size="lg")

            with gr.Accordion("Advanced Settings", open=False):
                seed = gr.Slider(label="Seed", minimum=0, maximum=MAX_SEED, value=10, step=1)
                randomize_seed = gr.Checkbox(label="Randomize Seed", value=True)

                with gr.Row():
                    width = gr.Number(label="Width", value=1536, precision=0)
                    height = gr.Number(label="Height", value=1024, precision=0)

            status_text = gr.Textbox(
                label="Status",
                value="就绪",
                interactive=False,
                lines=4
            )

        with gr.Column():
            output_video = gr.Video(label="Generated Video", autoplay=True)

    # 上传图片时自动调整
    input_image.change(
        fn=on_image_upload,
        inputs=[input_image, high_res, duration],
        outputs=[width, height, status_text],
    )

    # 切换高分辨率时自动调整
    high_res.change(
        fn=on_highres_toggle,
        inputs=[input_image, high_res, duration],
        outputs=[width, height, status_text],
    )

    # 切换时长时自动调整
    duration.change(
        fn=on_duration_change,
        inputs=[input_image, high_res, duration],
        outputs=[width, height, status_text],
    )

    generate_btn.click(
        fn=generate_video,
        inputs=[
            input_image,
            prompt,
            duration,
            enhance_prompt,
            seed,
            randomize_seed,
            height,
            width,
            high_res,
        ],
        outputs=[output_video, seed, status_text],
    )

css = """
.fillable {max-width: 1200px !important;}
"""

if __name__ == "__main__":
    demo.launch(theme=gr.themes.Citrus(), css=css)