import os
from PIL import Image

class ImageHandler:
	def __init__(self, base_dir: str):
		"""
		Initialize the ImageHandler.

		:param base_dir: Base directory for storing and retrieving images.
		"""
		self.base_dir = base_dir

	def get_image_path(self, filename: str) -> str:
		"""
		Construct the full path for a given image file.

		:param filename: Relative filename of the image.
		:return: Full path to the image.
		"""
		return os.path.join(self.base_dir, filename)

	def get_resized_image_path(self, filename: str, width: int, height: int) -> str:
		"""
		Construct the path for a resized image.

		:param filename: Original image filename.
		:param width: Desired width.
		:param height: Desired height.
		:return: Path to the resized image.
		"""
		return os.path.join(self.base_dir, f"resized_{width}x{height}_{filename}")

	def resize_and_save(self, original_path: str, resized_path: str, width: int, height: int):
		"""
		Resize and save the image if it doesn't already exist.

		:param original_path: Path to the original image file.
		:param resized_path: Path to save the resized image.
		:param width: Desired width.
		:param height: Desired height.
		"""
		if not os.path.exists(resized_path):
			with Image.open(original_path) as img:
				img_resized = img.resize((width, height))
				img_resized.save(resized_path, format="JPEG")

	def generate_image_tag(self, src: str, width: int, height: int, css_class: str = "", alt: str = "") -> str:
		"""
		Generate an HTML <img> tag and ensure the image exists with the specified dimensions.

		:param src: Relative path to the original image.
		:param width: Desired width of the image.
		:param height: Desired height of the image.
		:param css_class: Optional CSS class to add to the <img> tag.
		:param alt: Alternative text for the image.
		:return: HTML <img> tag.
		"""
		original_path = self.get_image_path(src)
		if not os.path.isfile(original_path):
			raise FileNotFoundError(f"Image not found: {src}")

		# Construct resized image path
		resized_filename = f"resized_{width}x{height}_{os.path.basename(src)}"
		resized_path = self.get_resized_image_path(src, width, height)

		# Resize and save the image if necessary
		self.resize_and_save(original_path, resized_path, width, height)

		# Return the <img> tag
		class_attr = f' class="{css_class}"' if css_class else ""
		alt_attr = f' alt="{alt}"' if alt else ""
		return f'<img src="/{resized_path}" width="{width}" height="{height}"{alt_attr}{class_attr}>'
