import os
import sys
import time
import logging
import datetime
from pathlib import Path
from typing import Optional, Tuple, List, Union
import warnings
warnings.filterwarnings("ignore")

import numpy as np
from PIL import Image, ImageDraw, ImageFont
import imageio
import imageio_ffmpeg

logging.basicConfig(level=logging.INFO, format='%(asctime)s [%(levelname)s] %(name)s: %(message)s')
logger = logging.getLogger("LegionVideo")

# Output directory
OUTPUT_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "outputs")
os.makedirs(OUTPUT_DIR, exist_ok=True)

# Model directories
MODEL_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "models")
T2V_MODEL_DIR = os.path.join(MODEL_DIR, "t2v")
I2V_MODEL_DIR = os.path.join(MODEL_DIR, "i2v")

# Constants
DEFAULT_NEGATIVE_PROMPT = ""


class MockVideoGenerator:
    def __init__(self):
        self.device = "cpu"
        logger.info("MockVideoGenerator initialized - will create test pattern videos")

    def generate_video(self, prompt: str, num_frames: int, width: int, height: int) -> np.ndarray:
        frames = []
        for i in range(num_frames):
            frame = np.zeros((height, width, 3), dtype=np.uint8)
            progress = i / max(num_frames - 1, 1)
            # Moving color bar
            bar_x = int(progress * (width - width // 4))
            frame[:, bar_x:bar_x + width // 4] = [
                int(128 + 127 * np.sin(progress * 4)),
                int(128 + 127 * np.sin(progress * 4 + 2)),
                int(128 + 127 * np.sin(progress * 4 + 4))
            ]
            # Text overlay with prompt
            frame_pil = Image.fromarray(frame)
            draw = ImageDraw.Draw(frame_pil)
            draw.text((10, 10), prompt, fill=(255, 255, 255))
            draw.text((10, height - 30), f"LEGION AI | Frame {i+1}/{num_frames}", fill=(200, 200, 200))
            frames.append(np.array(frame_pil))
        return np.stack(frames)


class LegionVideoGenerator:
    """LEGION Video Generator - High-quality video generation system.

    Features:
    - Text-to-Video generation
    - Image-to-Video generation
    - Temporal enhancement for smooth frame transitions
    - QWatermark system (configurable quality watermark overlay)
    - CPU fallback with mock generation when GPU/model unavailable
    """

    def __init__(self, model_path: Optional[str] = None):
        self.device = self._detect_device()
        self.pipe_t2v = None
        self.pipe_i2v = None
        self.mock_mode = False
        self.mock_gen = None

        logger.info(f"LEGION Video Generator initializing (device: {self.device})")

        # Try loading real models
        if not self._load_models(model_path):
            logger.warning("Real model loading failed - using mock generator fallback")
            self.mock_mode = True
            self.mock_gen = MockVideoGenerator()

        logger.info("LEGION Video Generator initialized successfully")

    def _detect_device(self) -> str:
        try:
            import torch
            if torch.cuda.is_available():
                logger.info(f"GPU detected: {torch.cuda.get_device_name(0)}")
                return "cuda"
        except Exception:
            pass
        logger.info("No GPU detected - using CPU")
        return "cpu"

    def _check_memory_sufficient(self) -> bool:
        try:
            import psutil
            available_gb = psutil.virtual_memory().available / (1024 ** 3)
            logger.info(f"Available system RAM: {available_gb:.1f} GB")
            if available_gb < 20.0:
                logger.warning(
                    f"Insufficient RAM ({available_gb:.1f} GB < 20 GB required) "
                    f"to load 8.3B parameter model - using mock fallback"
                )
                return False
            return True
        except ImportError:
            try:
                with open('/proc/meminfo', 'r') as f:
                    for line in f:
                        if 'MemAvailable' in line:
                            available_kb = int(line.split()[1])
                            available_gb = available_kb / (1024 * 1024)
                            logger.info(f"Available system RAM: {available_gb:.1f} GB")
                            if available_gb < 20.0:
                                logger.warning(
                                    f"Insufficient RAM ({available_gb:.1f} GB < 20 GB) - using mock"
                                )
                                return False
                            return True
            except Exception as e:
                logger.warning(f"Cannot check RAM: {e}")
            logger.warning("Cannot check RAM - defaulting to mock mode on CPU")
            return False

    def _load_models(self, model_path: Optional[str] = None) -> bool:
        try:
            from diffusers import HunyuanVideo15Pipeline
        except ImportError as e:
            logger.warning(f"Required modules not available: {e}")
            return False

        # On CPU, check if we have enough memory first
        if self.device == "cpu":
            if not self._check_memory_sufficient():
                return False

        # Try T2V model from local path only
        t2v_path = model_path or T2V_MODEL_DIR
        try:
            if os.path.exists(os.path.join(t2v_path, "model_index.json")):
                logger.info(f"Loading T2V model from local path: {t2v_path}")
                self.pipe_t2v = HunyuanVideo15Pipeline.from_pretrained(
                    t2v_path,
                    torch_dtype=torch.float32,
                )
            else:
                logger.warning(f"T2V model not found at {t2v_path}")
                return False

            # Enable memory optimizations
            if self.pipe_t2v is not None:
                self.pipe_t2v.enable_model_cpu_offload()
                if hasattr(self.pipe_t2v, 'vae') and hasattr(self.pipe_t2v.vae, 'enable_tiling'):
                    self.pipe_t2v.vae.enable_tiling()
                self.pipe_t2v.enable_attention_slicing()

        except Exception as e:
            logger.warning(f"Could not load T2V model: {e}")

        # Try I2V model from local path only
        try:
            i2v_path = I2V_MODEL_DIR
            if os.path.exists(os.path.join(i2v_path, "model_index.json")):
                logger.info(f"Loading I2V model from local path: {i2v_path}")
                self.pipe_i2v = HunyuanVideo15Pipeline.from_pretrained(
                    i2v_path,
                    torch_dtype=torch.float32,
                )

                # Enable memory optimizations on I2V
                if self.pipe_i2v is not None:
                    self.pipe_i2v.enable_model_cpu_offload()
                    if hasattr(self.pipe_i2v, 'vae') and hasattr(self.pipe_i2v.vae, 'enable_tiling'):
                        self.pipe_i2v.vae.enable_tiling()
                    self.pipe_i2v.enable_attention_slicing()

        except Exception as e:
            logger.warning(f"Could not load I2V model: {e}")

        return self.pipe_t2v is not None or self.pipe_i2v is not None

    def generate_from_text(
        self,
        prompt: str,
        negative_prompt: str = DEFAULT_NEGATIVE_PROMPT,
        num_frames: int = 49,
        width: int = 480,
        height: int = 480,
        num_inference_steps: int = 50,
        guidance_scale: float = 6.0,
        watermark_strength: float = 0.0,
        seed: Optional[int] = None,
    ) -> str:
        """Generate a video from a text prompt.

        Args:
            prompt: Text description of the video to generate
            negative_prompt: Things to avoid in the video
            num_frames: Number of frames to generate (1-129)
            width, height: Video resolution
            num_inference_steps: Diffusion inference steps
            guidance_scale: Classifier-free guidance scale
            watermark_strength: QWatermark opacity (0.0 = none, 1.0 = full)
            seed: Random seed for reproducibility

        Returns:
            Path to the generated MP4 file
        """
        logger.info(f"T2V: '{prompt[:60]}...' ({num_frames}f, {width}x{height}, {num_inference_steps}steps)")

        if self.mock_mode:
            return self._generate_mock_video(prompt, num_frames, width, height, watermark_strength, "t2v")

        if self.pipe_t2v is None:
            raise RuntimeError("T2V pipeline not available")

        try:
            import torch
            generator = None
            if seed is not None:
                generator = torch.Generator(device=self.device).manual_seed(seed)

            output = self.pipe_t2v(
                prompt=prompt,
                negative_prompt=negative_prompt,
                num_frames=num_frames,
                width=width,
                height=height,
                num_inference_steps=num_inference_steps,
                guidance_scale=guidance_scale,
                generator=generator,
            )
            frames = output.frames[0]

            return self._export_video(frames, prompt, watermark_strength, "t2v")
        except Exception as e:
            logger.error(f"T2V generation failed: {e}")
            raise

    def generate_from_image(
        self,
        image_path: str,
        prompt: str = "",
        negative_prompt: str = DEFAULT_NEGATIVE_PROMPT,
        num_frames: int = 49,
        width: int = 480,
        height: int = 480,
        num_inference_steps: int = 50,
        guidance_scale: float = 6.0,
        watermark_strength: float = 0.0,
        seed: Optional[int] = None,
    ) -> str:
        """Generate a video from an input image + text prompt.

        Args:
            image_path: Path to the conditioning image
            prompt: Text description of motion/action
            negative_prompt: Things to avoid
            num_frames, width, height, num_inference_steps, guidance_scale: Generation params
            watermark_strength: QWatermark opacity
            seed: Random seed

        Returns:
            Path to the generated MP4 file
        """
        logger.info(f"I2V from '{image_path}': '{prompt[:60]}...'")

        if self.mock_mode:
            return self._generate_mock_video(prompt, num_frames, width, height, watermark_strength, "i2v")

        from PIL import Image as PILImage

        if not os.path.exists(image_path):
            raise FileNotFoundError(f"Image not found: {image_path}")

        input_image = PILImage.open(image_path).convert("RGB")

        if self.pipe_i2v is not None:
            try:
                import torch
                generator = None
                if seed is not None:
                    generator = torch.Generator(device=self.device).manual_seed(seed)

                output = self.pipe_i2v(
                    image=input_image,
                    prompt=prompt,
                    negative_prompt=negative_prompt,
                    num_frames=num_frames,
                    width=width,
                    height=height,
                    num_inference_steps=num_inference_steps,
                    guidance_scale=guidance_scale,
                    generator=generator,
                )
                frames = output.frames[0]
            except Exception as e:
                logger.error(f"I2V generation failed: {e}")
                raise
        elif self.pipe_t2v is not None:
            # Use T2V pipeline as fallback
            logger.warning("I2V pipeline not available, falling back to T2V with prompt style")
            enhanced_prompt = prompt + ", based on the provided image style"
            try:
                import torch
                generator = None
                if seed is not None:
                    generator = torch.Generator(device=self.device).manual_seed(seed)

                output = self.pipe_t2v(
                    prompt=enhanced_prompt,
                    negative_prompt=negative_prompt,
                    num_frames=num_frames,
                    width=width,
                    height=height,
                    num_inference_steps=num_inference_steps,
                    guidance_scale=guidance_scale,
                    generator=generator,
                )
                frames = output.frames[0]
            except Exception as e:
                logger.error(f"T2V fallback generation failed: {e}")
                raise
        else:
            raise RuntimeError("No video generation pipeline available")

        return self._export_video(frames, prompt, watermark_strength, "i2v")

    def _generate_mock_video(
        self, prompt: str, num_frames: int, width: int, height: int,
        watermark_strength: float, mode: str
    ) -> str:
        logger.info("Using mock generator (model unavailable)")
        frames = self.mock_gen.generate_video(prompt, num_frames, width, height)
        return self._export_video(frames, prompt, watermark_strength, mode)

    def _temporal_enhancement(self, frames: np.ndarray, strength: float = 0.5) -> np.ndarray:
        """Apply temporal smoothing to reduce frame-to-frame artifacts.

        Applies a lightweight Gaussian filter across the temporal dimension
        to smooth out flickering and jitter between consecutive frames.

        Args:
            frames: Video frames as numpy array (T, H, W, C)
            strength: Smoothing intensity (0.0 = none, 1.0 = maximum)

        Returns:
            Temporally smoothed frames
        """
        if not isinstance(frames, np.ndarray):
            return frames

        T, H, W, C = frames.shape
        if T < 3:
            return frames  # Not enough frames to smooth

        # Apply lightweight temporal smoothing
        kernel_size = max(3, int(5 * strength))
        if kernel_size % 2 == 0:
            kernel_size += 1

        # Simple temporal blur: average adjacent frames
        smoothed = frames.copy()
        half_k = min(kernel_size // 2, T // 2)

        for t in range(1, T - 1):
            left = max(0, t - half_k)
            right = min(T, t + half_k + 1)
            smoothed[t] = np.mean(frames[left:right], axis=0)

        return smoothed

    def _export_video(
        self, frames, prompt: str, watermark_strength: float, mode: str
    ) -> str:
        # Apply temporal enhancement
        frames = self._temporal_enhancement(frames)

        # Apply QWatermark
        if watermark_strength > 0:
            frames = self.apply_qwatermark(frames, strength=watermark_strength)

        # Generate filename
        timestamp = datetime.datetime.now().strftime("%Y%m%d_%H%M%S")
        safe_prompt = "".join(c if c.isalnum() or c in " _-" else "_" for c in prompt[:30])
        filename = f"legion_{mode}_{timestamp}_{safe_prompt}.mp4"
        output_path = os.path.join(OUTPUT_DIR, filename)

        # Export frames to MP4
        if isinstance(frames, np.ndarray):
            if frames.dtype != np.uint8:
                frames = (np.clip(frames, 0, 1) * 255).astype(np.uint8)
            imageio.mimsave(output_path, frames, fps=8, codec='libx264',
                            quality=8, pixelformat='yuv420p')
        else:
            frame_list = []
            for f in frames:
                if hasattr(f, 'mode'):
                    frame_list.append(np.array(f.convert("RGB")))
                else:
                    frame_list.append(np.array(f))
            imageio.mimsave(output_path, frame_list, fps=8, codec='libx264',
                            quality=8, pixelformat='yuv420p')

        file_size = os.path.getsize(output_path)
        logger.info(f"Video exported: {output_path} ({file_size / 1024:.1f} KB)")
        return output_path

    def apply_qwatermark(
        self,
        frames,
        strength: float = 0.3,
        text: str = "LEGION",
        position: str = "bottom-right",
        font_size: int = 36,
        opacity: float = 0.3,
    ) -> np.ndarray:
        """Apply LEGION QWatermark to video frames.

        The QWatermark is a semi-transparent quality assurance marker
        that indicates the video was generated by the LEGION system.

        Args:
            frames: Video frames (numpy array or list of PIL Images)
            strength: Overall watermark intensity (0.0-1.0)
            text: Watermark text
            position: Position on frame
            font_size: Font size for watermark text
            opacity: Text opacity (0.0-1.0)

        Returns:
            Watermarked frames as numpy array
        """
        opacity = opacity * strength

        if isinstance(frames, np.ndarray):
            pil_frames = [Image.fromarray(f) for f in frames]
        else:
            pil_frames = [Image.fromarray(np.array(f)) for f in frames]

        watermarked = []
        for frame in pil_frames:
            frame = frame.convert("RGBA")
            overlay = Image.new("RGBA", frame.size, (0, 0, 0, 0))
            draw = ImageDraw.Draw(overlay)

            try:
                font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf", font_size)
            except (IOError, OSError):
                try:
                    font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", font_size)
                except (IOError, OSError):
                    font = ImageFont.load_default()

            bbox = draw.textbbox((0, 0), text, font=font)
            text_w = bbox[2] - bbox[0]
            text_h = bbox[3] - bbox[1]

            padding = 10
            margin = 15
            w, h = frame.size

            pos_map = {
                "top-left": (margin, margin),
                "top-right": (w - text_w - margin, margin),
                "bottom-left": (margin, h - text_h - margin),
                "center": ((w - text_w) // 2, (h - text_h) // 2),
                "bottom-right": (w - text_w - margin, h - text_h - margin),
            }
            x, y = pos_map.get(position, pos_map["bottom-right"])

            alpha_bg = int(40 * strength)
            draw.rectangle(
                [x - padding, y - padding, x + text_w + padding, y + text_h + padding],
                fill=(0, 0, 0, alpha_bg)
            )

            alpha_text = int(255 * opacity)
            draw.text((x, y), text, font=font, fill=(255, 255, 255, alpha_text))

            badge_text = "LEGION AI"
            try:
                small_font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", 12)
            except:
                small_font = ImageFont.load_default()
            bbox_badge = draw.textbbox((0, 0), badge_text, font=small_font)
            badge_w = bbox_badge[2] - bbox_badge[0]
            badge_h = bbox_badge[3] - bbox_badge[1]

            draw.rectangle([5, 5, 5 + badge_w + 8, 5 + badge_h + 4], fill=(0, 0, 0, alpha_bg))
            draw.text((9, 7), badge_text, font=small_font, fill=(200, 200, 200, alpha_text))

            watermarked_frame = Image.alpha_composite(frame, overlay)
            watermarked.append(np.array(watermarked_frame.convert("RGB")))

        return np.stack(watermarked)