//! Conversions for the internal Image type used by zbar.

use super::sys;

/// The internal image type used by zbar.
pub struct Image {
    pub(crate) inner: *mut sys::zbar_image_s,
    /// Set to store the data of inner, as it will otherwise be freed when the data is dropped.
    inner_data: Option<Vec<u8>>,
}

impl Image {
    /// Link: [`sys::zbar_image_create`]
    pub(crate) fn alloc() -> Self {
        Self {
            inner: unsafe { sys::zbar_image_create() },
            inner_data: None,
        }
    }

    /// Link: [`sys::zbar_image_set_format`]
    ///
    /// A FourCC code can be given in the format:
    ///
    /// ```rust,ignore
    /// self.set_format(b"Y800")
    /// ```
    pub(crate) fn set_format(&mut self, fourcc: &[u8; 4]) {
        let fourcc: u64 = fourcc[0] as u64
            | ((fourcc[1] as u64) << 8)
            | ((fourcc[2] as u64) << 16)
            | ((fourcc[3] as u64) << 24);
        unsafe { sys::zbar_image_set_format(self.inner, fourcc) }
    }

    /// Link: [`sys::zbar_image_set_size`]
    fn set_size(&mut self, width: u32, height: u32) {
        unsafe { sys::zbar_image_set_size(self.inner, width, height) }
    }

    /// Link: [`sys::zbar_image_set_data`]
    ///
    /// Accepts raw data in the configured format. See: [`Image::set_format`]
    fn set_data(&mut self, data: Vec<u8>) {
        unsafe {
            sys::zbar_image_set_data(
                self.inner,
                data.as_ptr().cast(),
                data.len() as u64,
                None,
            )
        }
        // keep data in self to avoid use after free when data goes out of scope
        let _ = self.inner_data.insert(data);
    }
}

#[cfg(feature = "image")]
mod impls {
    use super::*;
    use image::{DynamicImage, GenericImageView};

    impl From<DynamicImage> for Image {
        fn from(value: DynamicImage) -> Self {
            let mut image = Self::alloc();
            let (width, height) = value.dimensions();
            image.set_size(width, height);
            image.set_format(b"Y800");
            image.set_data(value.to_luma8().into_raw());
            image
        }
    }
}

impl Drop for Image {
    fn drop(&mut self) {
        unsafe { sys::zbar_image_destroy(self.inner) }
    }
}