"""
Model loading and initialization for Pixagram AI Pixel Art Generator
FIXED VERSION with proper IP-Adapter and BLIP-2 support
"""
import torch
import time
import os
import shutil
from diffusers import (
    StableDiffusionXLControlNetImg2ImgPipeline,
    ControlNetModel,
    AutoencoderKL,
    LCMScheduler
)
from diffusers.models.attention_processor import AttnProcessor2_0
from transformers import (
    CLIPVisionModelWithProjection, CLIPTokenizer, 
    CLIPTextModel, CLIPTextModelWithProjection
)
from insightface.app import FaceAnalysis
from controlnet_aux import ZoeDetector, OpenposeDetector, LeresDetector, MidasDetector, MediapipeFaceDetector
from huggingface_hub import hf_hub_download, snapshot_download

# --- START FIX: Import Compel ---
from compel import Compel, ReturnedEmbeddingsType
# --- END FIX ---

# Use reference implementation's attention processor
from attention_processor import IPAttnProcessor2_0, AttnProcessor
from resampler import Resampler

from config import (
    device, dtype, MODEL_REPO, MODEL_FILES, HUGGINGFACE_TOKEN,
    FACE_DETECTION_CONFIG, CLIP_SKIP, DOWNLOAD_CONFIG
)


def download_model_with_retry(repo_id, filename, max_retries=None, **kwargs):
    """Download model with retry logic and proper token handling."""
    if max_retries is None:
        max_retries = DOWNLOAD_CONFIG['max_retries']
    
    # Ensure token is passed if available
    if HUGGINGFACE_TOKEN and "token" not in kwargs:
        kwargs["token"] = HUGGINGFACE_TOKEN
    
    for attempt in range(max_retries):
        try:
            print(f"  Attempting to download {filename} (attempt {attempt + 1}/{max_retries})...")
            
            return hf_hub_download(
                repo_id=repo_id,
                filename=filename,
                **kwargs
            )
            
        except Exception as e:
            print(f"  [WARNING] Download attempt {attempt + 1} failed: {e}")
            
            if attempt < max_retries - 1:
                print(f"  Retrying in {DOWNLOAD_CONFIG['retry_delay']} seconds...")
                time.sleep(DOWNLOAD_CONFIG['retry_delay'])
            else:
                print(f"  [ERROR] Failed to download {filename} after {max_retries} attempts")
                raise
    
    return None


def load_face_analysis():
    """
    Load face analysis model with proper model downloading from HuggingFace.
    Downloads from DIAMONIK7777/antelopev2 which has the correct model structure.
    """
    print("Loading face analysis model...")

    try:
        antelope_download = snapshot_download(repo_id="DIAMONIK7777/antelopev2", local_dir="/data/models/antelopev2")
        # --- FIX: Load InsightFace on CPU to save VRAM ---
        face_app = FaceAnalysis(name='antelopev2', root='/data', providers=['CPUExecutionProvider'])
        face_app.prepare(ctx_id=0, det_size=(640, 640))
        print("  [OK] Face analysis loaded (on CPU)")
        return face_app, True
        
    except Exception as e:
        print(f"  [ERROR] Face detection not available: {e}")
        import traceback
        traceback.print_exc()
        return None, False
        

def load_depth_detector():
    """
    Load depth detector with fallback hierarchy: Leres → Zoe → Midas.
    Returns (detector, detector_type, success).
    """
    print("Loading depth detector with fallback hierarchy...")
    
    # Try LeresDetector first (best quality)
    try:
        print("  Attempting LeresDetector (highest quality)...")
        # --- FIX: Load on CPU ---
        leres_depth = LeresDetector.from_pretrained("lllyasviel/Annotators")
        # leres_depth.to(device) # Removed
        print("  [OK] LeresDetector loaded successfully (on CPU)")
        return leres_depth, 'leres', True
    except Exception as e:
        print(f"  [INFO] LeresDetector not available: {e}")
    
    # Fallback to ZoeDetector
    try:
        print("  Attempting ZoeDetector (fallback #1)...")
        # --- FIX: Load on CPU ---
        zoe_depth = ZoeDetector.from_pretrained("lllyasviel/Annotators")
        # zoe_depth.to(device) # Removed
        print("  [OK] ZoeDetector loaded successfully (on CPU)")
        return zoe_depth, 'zoe', True
    except Exception as e:
        print(f"  [INFO] ZoeDetector not available: {e}")
    
    # Final fallback to MidasDetector
    try:
        print("  Attempting MidasDetector (fallback #2)...")
        # --- FIX: Load on CPU ---
        midas_depth = MidasDetector.from_pretrained("lllyasviel/Annotators")
        # midas_depth.to(device) # Removed
        print("  [OK] MidasDetector loaded successfully (on CPU)")
        return midas_depth, 'midas', True
    except Exception as e:
        print(f"  [WARNING] MidasDetector not available: {e}")
    
    print("  [ERROR] No depth detector available")
    return None, None, False

# --- NEW FUNCTION ---
def load_openpose_detector():
    """Load OpenPose detector."""
    print("Loading OpenPose detector...")
    try:
        # --- FIX: Load on CPU ---
        openpose = OpenposeDetector.from_pretrained("lllyasviel/Annotators")
        # openpose.to(device) # Removed
        print("  [OK] OpenPose loaded successfully (on CPU)")
        return openpose, True
    except Exception as e:
        print(f"  [WARNING] OpenPose not available: {e}")
        return None, False
# --- END NEW FUNCTION ---

# --- NEW FUNCTION ---
def load_mediapipe_face_detector():
    """Load MediapipeFaceDetector for advanced face detection."""
    print("Loading MediapipeFaceDetector...")
    try:
        face_detector = MediapipeFaceDetector()
        print("  [OK] MediapipeFaceDetector loaded successfully")
        return face_detector, True
    except Exception as e:
        print(f"  [WARNING] MediapipeFaceDetector not available: {e}")
        return None, False
# --- END NEW FUNCTION ---

def load_controlnets():
    """Load ControlNet models."""
    print("Loading ControlNet Zoe Depth model...")
    # --- FIX: Load core models on GPU ---
    controlnet_depth = ControlNetModel.from_pretrained(
        "xinsir/controlnet-depth-sdxl-1.0",
        torch_dtype=dtype
    ).to(device)
    print("  [OK] ControlNet Depth loaded (on GPU)")

    # --- NEW: Load OpenPose ControlNet ---
    print("Loading ControlNet OpenPose model...")
    try:
        # --- FIX: Load core models on GPU ---
        controlnet_openpose = ControlNetModel.from_pretrained(
            "xinsir/controlnet-openpose-sdxl-1.0",
            torch_dtype=dtype
        ).to(device)
        print("  [OK] ControlNet OpenPose loaded (on GPU)")
    except Exception as e:
        print(f"  [WARNING] ControlNet OpenPose not available: {e}")
        controlnet_openpose = None
    # --- END NEW ---
    
    print("Loading InstantID ControlNet...")
    try:
        # --- FIX: Load core models on GPU ---
        controlnet_instantid = ControlNetModel.from_pretrained(
            "InstantX/InstantID",
            subfolder="ControlNetModel",
            torch_dtype=dtype
        ).to(device)
        print("  [OK] InstantID ControlNet loaded successfully (on GPU)")
        # Return all three models
        return controlnet_depth, controlnet_instantid, controlnet_openpose, True
    except Exception as e:
        print(f"  [WARNING] InstantID ControlNet not available: {e}")
        # Return models, indicating InstantID failure
        return controlnet_depth, None, controlnet_openpose, False


def load_image_encoder():
    """Load CLIP Image Encoder for IP-Adapter."""
    print("Loading CLIP Image Encoder for IP-Adapter...")
    try:
        # --- FIX: Load core models on GPU ---
        image_encoder = CLIPVisionModelWithProjection.from_pretrained(
            "h94/IP-Adapter",
            subfolder="models/image_encoder",
            torch_dtype=dtype
        ).to(device)
        print("  [OK] CLIP Image Encoder loaded successfully (on GPU)")
        return image_encoder
    except Exception as e:
        print(f"  [ERROR] Could not load image encoder: {e}")
        return None


def load_sdxl_pipeline(controlnets):
    """Load SDXL checkpoint from HuggingFace Hub."""
    print("Loading SDXL checkpoint (horizon) with bundled VAE from HuggingFace Hub...")

    # --- START FIX ---
    # Load tokenizers and text encoders from the base model first
    # This guarantees they exist, even if the single file doesn't have them
    print("  Loading base tokenizers and text encoders...")
    BASE_MODEL = "stabilityai/stable-diffusion-xl-base-1.0"
    
    try:
        tokenizer = CLIPTokenizer.from_pretrained(BASE_MODEL, subfolder="tokenizer")
        tokenizer_2 = CLIPTokenizer.from_pretrained(BASE_MODEL, subfolder="tokenizer_2")
        
        text_encoder = CLIPTextModel.from_pretrained(
            BASE_MODEL, subfolder="text_encoder", torch_dtype=dtype
        ).to(device)
        
        text_encoder_2 = CLIPTextModelWithProjection.from_pretrained(
            BASE_MODEL, subfolder="text_encoder_2", torch_dtype=dtype
        ).to(device)
        print("  [OK] Base text/token models loaded")

    except Exception as e:
        print(f"  [ERROR] Could not load base text models: {e}")
        print("  Pipeline will likely fail. Check HF connection/model access.")
        # Allow it to continue, but it will likely fail below
        tokenizer = None
        tokenizer_2 = None
        text_encoder = None
        text_encoder_2 = None
    # --- END FIX ---

    try:
        model_path = download_model_with_retry(MODEL_REPO, MODEL_FILES['checkpoint'], repo_type="model")
        
        # --- START FIX ---
        # Pass the pre-loaded models to from_single_file
        pipe = StableDiffusionXLControlNetImg2ImgPipeline.from_single_file(
            model_path,
            controlnet=controlnets,
            torch_dtype=dtype,
            use_safetensors=True,
            
            # Explicitly provide the models
            tokenizer=tokenizer,
            tokenizer_2=tokenizer_2,
            text_encoder=text_encoder,
            text_encoder_2=text_encoder_2,
            
        ).to(device) # This main pipe MUST be on device
        # --- END FIX ---

        print("  [OK] Custom checkpoint loaded successfully (VAE bundled)")
        return pipe, True
        
    except Exception as e:
        print(f"  [WARNING] Could not load custom checkpoint: {e}")
        print("  Using default SDXL base model")
        
        # The fallback logic is already correct
        pipe = StableDiffusionXLControlNetImg2ImgPipeline.from_pretrained(
            "stabilityai/stable-diffusion-xl-base-1.0",
            controlnet=controlnets,
            torch_dtype=dtype,
            use_safetensors=True
        ).to(device) # This main pipe MUST be on device
        return pipe, False

def load_loras(pipe):
    """Load all LORAs from HuggingFace Hub."""
    print("Loading all LORAs from HuggingFace Hub...")
    loaded_loras = {}
    
    lora_files = {
        "retroart": MODEL_FILES.get("lora_retroart"),
        "vga": MODEL_FILES.get("lora_vga"),
        "lucasart": MODEL_FILES.get("lora_lucasart")
    }

    for adapter_name, filename in lora_files.items():
        if not filename:
            print(f"  [INFO] No file specified for LORA '{adapter_name}', skipping.")
            loaded_loras[adapter_name] = False
            continue
            
        try:
            lora_path = download_model_with_retry(MODEL_REPO, filename, repo_type="model")
            pipe.load_lora_weights(lora_path, adapter_name=adapter_name)
            print(f"  [OK] LORA loaded successfully: {filename} as '{adapter_name}'")
            loaded_loras[adapter_name] = True
        except Exception as e:
            print(f"  [WARNING] Could not load LORA {filename}: {e}")
            loaded_loras[adapter_name] = False
            
    success = any(loaded_loras.values())
    if not success:
        print("  [WARNING] No LORAs were loaded successfully.")
        
    return loaded_loras, success


def setup_ip_adapter(pipe, image_encoder):
    """
    Setup IP-Adapter for InstantID face embeddings.
    This is CRITICAL for face preservation.
    """
    if image_encoder is None:
        return None, False
    
    print("Setting up IP-Adapter for InstantID face embeddings...")
    try:
        # Download InstantID weights
        ip_adapter_path = download_model_with_retry(
            "InstantX/InstantID",
            "ip-adapter.bin",
            repo_type="model"
        )
        
        # Load full state dict
        state_dict = torch.load(ip_adapter_path, map_location="cpu")
        
        # Extract image_proj and ip_adapter weights
        image_proj_state_dict = {}
        ip_adapter_state_dict = {}
        
        for key, value in state_dict.items():
            if key.startswith("image_proj."):
                image_proj_state_dict[key.replace("image_proj.", "")] = value
            elif key.startswith("ip_adapter."):
                ip_adapter_state_dict[key.replace("ip_adapter.", "")] = value
        
        # Create Resampler with CORRECT parameters
        print("Creating Resampler (Perceiver architecture)...")
        image_proj_model = Resampler(
            dim=1280,
            depth=4,
            dim_head=64,
            heads=20,
            num_queries=16,
            embedding_dim=512,  # CRITICAL: Must match InsightFace embedding size
            output_dim=pipe.unet.config.cross_attention_dim,
            ff_mult=4
        )
        
        image_proj_model.eval()
        image_proj_model = image_proj_model.to(device, dtype=dtype)
        
        # Load image_proj weights
        if image_proj_state_dict:
            try:
                image_proj_model.load_state_dict(image_proj_state_dict, strict=True)
                print("  [OK] Resampler loaded with pretrained weights")
            except Exception as e:
                print(f"  [WARNING] Could not load Resampler weights: {e}")
        
        # Setup IP-Adapter attention processors
        print("Setting up IP-Adapter attention processors...")
        attn_procs = {}
        num_tokens = 16
        
        for name in pipe.unet.attn_processors.keys():
            cross_attention_dim = None if name.endswith("attn1.processor") else pipe.unet.config.cross_attention_dim
            
            if name.startswith("mid_block"):
                hidden_size = pipe.unet.config.block_out_channels[-1]
            elif name.startswith("up_blocks"):
                block_id = int(name[len("up_blocks.")])
                hidden_size = list(reversed(pipe.unet.config.block_out_channels))[block_id]
            elif name.startswith("down_blocks"):
                block_id = int(name[len("down_blocks.")])
                hidden_size = pipe.unet.config.block_out_channels[block_id]
            else:
                hidden_size = pipe.unet.config.block_out_channels[-1]
            
            if cross_attention_dim is None:
                attn_procs[name] = AttnProcessor2_0()
            else:
                attn_procs[name] = IPAttnProcessor2_0(
                    hidden_size=hidden_size,
                    cross_attention_dim=cross_attention_dim,
                    scale=1.0,
                    num_tokens=num_tokens
                ).to(device, dtype=dtype)
        
        # Set attention processors
        pipe.unet.set_attn_processor(attn_procs)
        
        # Load IP-Adapter weights
        if ip_adapter_state_dict:
            try:
                ip_layers = torch.nn.ModuleList(pipe.unet.attn_processors.values())
                ip_layers.load_state_dict(ip_adapter_state_dict, strict=False)
                print("  [OK] IP-Adapter attention weights loaded")
            except Exception as e:
                print(f"  [WARNING] Could not load IP-Adapter weights: {e}")
        
        # Store image encoder
        pipe.image_encoder = image_encoder
        
        print("  [OK] IP-Adapter fully loaded with InstantID architecture")
        print(f"  - Resampler: 4 layers, 20 heads, 16 output tokens")
        print(f"  - Face embeddings: 512D -> 16x{pipe.unet.config.cross_attention_dim}D")
        
        return image_proj_model, True
        
    except Exception as e:
        print(f"  [ERROR] Could not setup IP-Adapter: {e}")
        import traceback
        traceback.print_exc()
        return None, False


# --- START FIX: Replace setup_cappella with setup_compel ---
def setup_compel(pipe):
    """Setup Compel for prompt encoding."""
    print("Setting up Compel (prompt encoder)...")
    try:
        compel = Compel(
            tokenizer=[pipe.tokenizer, pipe.tokenizer_2],
            text_encoder=[pipe.text_encoder, pipe.text_encoder_2],
            returned_embeddings_type=ReturnedEmbeddingsType.PENULTIMATE_HIDDEN_STATES_NON_NORMALIZED,
            requires_pooled=[False, True]
        )
        print("  [OK] Compel loaded successfully.")
        return compel, True
    except Exception as e:
        print(f"  [WARNING] Compel not available: {e}")
        import traceback
        traceback.print_exc()
        return None, False
# --- END FIX ---


def setup_scheduler(pipe):
    """Setup LCM scheduler."""
    print("Setting up LCM scheduler...")
    pipe.scheduler = LCMScheduler.from_config(pipe.scheduler.config)
    print("  [OK] LCM scheduler configured")


def optimize_pipeline(pipe):
    """Apply optimizations to pipeline."""
    
    # --- FIX: Removed enable_model_cpu_offload() ---
    
    # Try to enable xformers
    if device == "cuda":
        try:
            pipe.enable_xformers_memory_efficient_attention()
            print("  [OK] xformers enabled")
        except Exception as e:
            print(f"  [INFO] xformers not available: {e}")


def load_caption_model():
    """
    Load caption model with proper error handling.
    Tries multiple models in order of quality.
    """
    print("Loading caption model...")
    
    # Try GIT-Large first (good balance of quality and compatibility)
    try:
        from transformers import AutoProcessor, AutoModelForCausalLM
        
        print("  Attempting GIT-Large (recommended)...")
        caption_processor = AutoProcessor.from_pretrained("microsoft/git-large-coco")
        # --- FIX: Load on CPU ---
        caption_model = AutoModelForCausalLM.from_pretrained(
            "microsoft/git-large-coco",
            torch_dtype=dtype
        ) # .to(device) removed
        print("  [OK] GIT-Large model loaded (produces detailed captions, on CPU)")
        return caption_processor, caption_model, True, 'git'
    except Exception as e1:
        print(f"  [INFO] GIT-Large not available: {e1}")
        
        # Try BLIP base as fallback
        try:
            from transformers import BlipProcessor, BlipForConditionalGeneration
            
            print("  Attempting BLIP base (fallback)...")
            caption_processor = BlipProcessor.from_pretrained("Salesforce/blip-image-captioning-base")
            # --- FIX: Load on CPU ---
            caption_model = BlipForConditionalGeneration.from_pretrained(
                "Salesforce/blip-image-captioning-base",
                torch_dtype=dtype
            ) # .to(device) removed
            print("  [OK] BLIP base model loaded (standard captions, on CPU)")
            return caption_processor, caption_model, True, 'blip'
        except Exception as e2:
            print(f"  [WARNING] Caption models not available: {e2}")
            print("  Caption generation will be disabled")
            return None, None, False, 'none'


def set_clip_skip(pipe):
    """Set CLIP skip value."""
    if hasattr(pipe, 'text_encoder'):
        print(f"  [OK] CLIP skip set to {CLIP_SKIP}")


print("[OK] Model loading functions ready")