use clap::Parser;
use image::{GenericImage, ImageFormat, Pixel};
use serde::{Deserialize, Serialize};

/// Extract Information About An Image or Spritesheet
#[derive(Debug, Clone, Parser, Serialize, Deserialize)]
#[clap(author, version = "0.7.0")]
pub struct Info {
	/// The path to the image file
	#[serde(default)]
	pub input: String,
	/// The output path for a JSON formatted information file. Omit to print to stdout
	#[serde(default)]
	pub output: Option<String>,
	/// The size of each tile in the spritesheet. Assumed to be square tiles
	#[clap(short, long, default_value = None)]
	#[serde(default)]
	pub tile_size: Option<u32>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ImageInfo {
	image_width: u32,
	image_height: u32,
	image_format: String,
	#[serde(skip_serializing_if = "Option::is_none")]
	tile_width: Option<u32>,
	#[serde(skip_serializing_if = "Option::is_none")]
	tile_height: Option<u32>,
	#[serde(skip_serializing_if = "Option::is_none")]
	rows: Option<u32>,
	#[serde(skip_serializing_if = "Option::is_none")]
	columns: Option<u32>,
}

impl Info {
	pub fn run<T: GenericImage>(&self, image: &T) -> anyhow::Result<ImageInfo>
	where
		T::Pixel: 'static,
		<T::Pixel as Pixel>::Subpixel: 'static,
	{
		let format = ImageFormat::from_path(&self.input)?;
		let image_width = image.width();
		let image_height = image.height();

		let mut image_info = ImageInfo {
			image_width,
			image_height,
			image_format: format!("{:?}", format).to_lowercase(),
			tile_width: None,
			tile_height: None,
			rows: None,
			columns: None,
		};

		if let Some(tile_size) = self.tile_size {
			image_info.tile_width = Some(tile_size);
			image_info.tile_height = Some(tile_size);
			image_info.rows = Some(image_info.image_height / tile_size);
			image_info.columns = Some(image_info.image_width / tile_size);
		}

		Ok(image_info)
	}
}