#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
TIF Image Cropping Utility

This script provides functionality for cropping TIF images by automatically
detecting content areas and removing excess whitespace.
"""

import argparse
import os
from typing import Optional, Tuple

import cv2
import numpy as np


def find_content_area(image_path: str) -> Tuple[int, int, int, int]:
    """
    Find the bounding box of the content area in an image.

    Args:
        image_path: Path to the image file

    Returns:
        Tuple containing (x, y, width, height) of the content area

    Raises:
        FileNotFoundError: If the image cannot be read
    """
    # Read the image
    img = cv2.imread(image_path)
    if img is None:
        raise FileNotFoundError(f"Unable to read image file: {image_path}")

    # Convert to grayscale
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

    # Apply adaptive thresholding for better detection of content
    # This works better for images with varying brightness
    thresh = cv2.adaptiveThreshold(
        gray, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY_INV, 11, 2
    )

    # Alternative method: standard thresholding
    # _, thresh = cv2.threshold(gray, 250, 255, cv2.THRESH_BINARY_INV)

    # Find all non-zero points (colored or non-white pixels)
    points = cv2.findNonZero(thresh)

    # Get the bounding rectangle around the non-zero points
    if points is not None:
        x, y, w, h = cv2.boundingRect(points)
        return x, y, w, h
    else:
        # If no points found, return the whole image
        h, w = img.shape[:2]
        return 0, 0, w, h


def resize_image(
    img: np.ndarray,
    target_dpi: int = 600,
    max_width: int = 2000,
    max_height: int = 2000,
    verbose: bool = False,
) -> np.ndarray:
    """
    Resize an image to meet target DPI and maximum dimensions constraints.

    Args:
        img: Input image as numpy array
        target_dpi: Target DPI (dots per inch) for the image
        max_width: Maximum width in pixels
        max_height: Maximum height in pixels
        verbose: Whether to print detailed information

    Returns:
        Resized image as numpy array
    """
    height, width = img.shape[:2]

    # Calculate if resizing is needed
    if width > max_width or height > max_height:
        # Determine the scaling factor to fit within max dimensions
        scale_factor = min(max_width / width, max_height / height)

        # Calculate new dimensions
        new_width = int(width * scale_factor)
        new_height = int(height * scale_factor)

        if verbose:
            print(f"Resizing image from {width}x{height} to {new_width}x{new_height}")
            print(f"Scale factor: {scale_factor:.2f}")

        # Resize the image
        resized_img = cv2.resize(
            img, (new_width, new_height), interpolation=cv2.INTER_AREA
        )
        return resized_img
    else:
        if verbose:
            print(
                f"No resizing needed, image dimensions {width}x{height} are within limits"
            )
        return img


def crop_tif(
    input_path: str,
    output_path: Optional[str] = None,
    margin: int = 30,
    resize: bool = True,
    target_dpi: int = 600,
    max_width: int = 2000,
    max_height: int = 2000,
    overwrite: bool = False,
    verbose: bool = False,
) -> None:
    """
    Crop a TIF image to its content area with a specified margin and optionally resize it.

    Args:
        input_path: Path to the input TIF image
        output_path: Path to save the cropped image (defaults to input_path if overwrite=True)
        margin: Margin in pixels to add around the content area
        resize: Whether to resize the image to meet target constraints
        target_dpi: Target DPI for the resized image
        max_width: Maximum width in pixels for the resized image
        max_height: Maximum height in pixels for the resized image
        overwrite: Whether to overwrite the input file
        verbose: Whether to print detailed information

    Raises:
        FileNotFoundError: If the input image cannot be read
        ValueError: If output path is not specified and overwrite is False
    """
    # Determine output path
    if output_path is None:
        if overwrite:
            output_path = input_path
        else:
            raise ValueError("output_path must be specified if overwrite=False")

    # Read the image
    img = cv2.imread(input_path)
    if img is None:
        raise FileNotFoundError(f"Unable to read image file: {input_path}")

    original_height, original_width = img.shape[:2]

    if verbose:
        print(f"Original image dimensions: {original_width}x{original_height}")

    # Find the content area
    x, y, w, h = find_content_area(input_path)

    if verbose:
        print(f"Content area detected at: x={x}, y={y}, width={w}, height={h}")

    # Calculate the coordinates with margin, clamping to the image boundaries
    x_start = max(x - margin, 0)
    y_start = max(y - margin, 0)
    x_end = min(x + w + margin, img.shape[1])
    y_end = min(y + h + margin, img.shape[0])

    if verbose:
        print(f"Cropping to: x={x_start}:{x_end}, y={y_start}:{y_end}")
        print(f"New dimensions: {x_end - x_start}x{y_end - y_start}")

    # Crop the image using the bounding rectangle with margin
    cropped_img = img[y_start:y_end, x_start:x_end]

    # Resize the image if requested
    if resize:
        cropped_img = resize_image(
            cropped_img, target_dpi, max_width, max_height, verbose
        )

    # Save the processed image
    cv2.imwrite(output_path, cropped_img)

    # Calculate space saved
    final_height, final_width = cropped_img.shape[:2]
    area_reduction = 1 - (
        (final_width * final_height) / (original_width * original_height)
    )
    area_reduction_pct = area_reduction * 100

    print(f"Image processed: {input_path}")
    print(
        f"Size changed from {original_width}x{original_height} to {final_width}x{final_height}"
    )
    print(f"Saved {area_reduction_pct:.1f}% of the original area")

    if output_path != input_path:
        print(f"Saved to: {output_path}")


def batch_crop_tifs(
    directory: str,
    output_directory: Optional[str] = None,
    margin: int = 30,
    resize: bool = True,
    target_dpi: int = 600,
    max_width: int = 2000,
    max_height: int = 2000,
    recursive: bool = False,
    verbose: bool = False,
) -> None:
    """
    Process all TIF files in a directory.

    Args:
        directory: Directory containing TIF files to process
        output_directory: Directory to save processed files (defaults to same as input)
        margin: Margin to add around the content area
        resize: Whether to resize images to meet target constraints
        target_dpi: Target DPI for resized images
        max_width: Maximum width in pixels for resized images
        max_height: Maximum height in pixels for resized images
        recursive: Whether to process subdirectories
        verbose: Whether to print detailed information
    """
    if not os.path.isdir(directory):
        raise ValueError(f"Directory not found: {directory}")

    # Create output directory if it doesn't exist
    if output_directory and not os.path.exists(output_directory):
        os.makedirs(output_directory)

    # Get the list of TIF files
    files = []
    if recursive:
        for root, _, filenames in os.walk(directory):
            for filename in filenames:
                if filename.lower().endswith((".tif", ".tiff")):
                    files.append(os.path.join(root, filename))
    else:
        files = [
            os.path.join(directory, f)
            for f in os.listdir(directory)
            if f.lower().endswith((".tif", ".tiff"))
        ]

    print(f"Found {len(files)} TIF files to process")

    # Process each file
    for index, file_path in enumerate(files):
        if verbose:
            print(f"\nProcessing [{index + 1}/{len(files)}]: {file_path}")
        else:
            print(
                f"Processing [{index + 1}/{len(files)}]: {os.path.basename(file_path)}"
            )

        # Determine output path
        if output_directory:
            rel_path = os.path.relpath(file_path, directory)
            output_path = os.path.join(output_directory, rel_path)

            # Create subdirectories if needed
            output_subdir = os.path.dirname(output_path)
            if not os.path.exists(output_subdir):
                os.makedirs(output_subdir)
        else:
            output_path = file_path

        # Process the image
        try:
            crop_tif(
                file_path,
                output_path,
                margin,
                resize,
                target_dpi,
                max_width,
                max_height,
                output_path == file_path,
                verbose,
            )
        except Exception as e:
            print(f"Error processing {file_path}: {e}")


def main():
    """Main function to parse arguments and execute the appropriate action."""
    # Set up argument parser
    parser = argparse.ArgumentParser(
        description="Process TIF images: crop to content area, resize, and optimize for publications.",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )

    # Add subparsers for the different modes
    subparsers = parser.add_subparsers(dest="mode", help="Operation mode")

    # Single file mode
    file_parser = subparsers.add_parser("file", help="Process a single file")
    file_parser.add_argument("-i", "--input", required=True, help="Input TIF file path")
    file_parser.add_argument(
        "-o", "--output", help="Output TIF file path (defaults to input if --overwrite)"
    )
    file_parser.add_argument(
        "--overwrite", action="store_true", help="Overwrite the input file"
    )

    # Batch mode
    batch_parser = subparsers.add_parser("batch", help="Process multiple files")
    batch_parser.add_argument(
        "-d", "--directory", required=True, help="Directory containing TIF files"
    )
    batch_parser.add_argument(
        "-o", "--output-directory", help="Output directory for processed files"
    )
    batch_parser.add_argument(
        "-r",
        "--recursive",
        action="store_true",
        help="Process subdirectories recursively",
    )

    # Common arguments
    for subparser in [file_parser, batch_parser]:
        subparser.add_argument(
            "--margin", type=int, default=30, help="Margin size around the content area"
        )
        subparser.add_argument(
            "--no-resize", action="store_true", help="Disable automatic resizing"
        )
        subparser.add_argument(
            "--dpi", type=int, default=600, help="Target DPI for resized images"
        )
        subparser.add_argument(
            "--max-width", type=int, default=2000, help="Maximum width in pixels"
        )
        subparser.add_argument(
            "--max-height", type=int, default=2000, help="Maximum height in pixels"
        )
        subparser.add_argument(
            "-v", "--verbose", action="store_true", help="Enable verbose output"
        )

    # Parse arguments
    args = parser.parse_args()

    # Execute the appropriate action
    if args.mode == "file":
        crop_tif(
            args.input,
            args.output,
            args.margin,
            not args.no_resize,  # Invert --no-resize flag to get resize boolean
            args.dpi,
            args.max_width,
            args.max_height,
            args.overwrite,
            args.verbose,
        )
    elif args.mode == "batch":
        batch_crop_tifs(
            args.directory,
            args.output_directory,
            args.margin,
            not args.no_resize,  # Invert --no-resize flag to get resize boolean
            args.dpi,
            args.max_width,
            args.max_height,
            args.recursive,
            args.verbose,
        )
    else:
        parser.print_help()


if __name__ == "__main__":
    main()