//! Coordinate transformation module for Wayland output transforms.
//!
//! Historically exposed a family of `Rect`/`screen_to_frame`/`fit_inside_bounds`
//! helpers for ROI-based capture clipping. Those were never wired into the
//! capture pipeline (we capture full frames and let FFmpeg's filter graph handle
//! any scaling/rotation); they have been removed. Only `Transform` and the
//! `transpose_if_transform_transposed` helper remain — both are actively used by
//! `state.rs` and `avhw.rs`.

/// Wayland output transform enum, matching `wl_output::Transform`.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Transform {
    Normal,
    Normal90,
    Normal180,
    Normal270,
    Flipped,
    Flipped90,
    Flipped180,
    Flipped270,
}

/// Swap width and height for 90° or 270° rotations.
///
/// After a quarter-turn rotation the output dimensions are transposed
/// relative to the input. This helper returns `(h, w)` for those cases
/// and `(w, h)` unchanged otherwise.
pub fn transpose_if_transform_transposed(transform: Transform, w: i32, h: i32) -> (i32, i32) {
    match transform {
        Transform::Normal90
        | Transform::Normal270
        | Transform::Flipped90
        | Transform::Flipped270 => (h, w),
        _ => (w, h),
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    // ── transpose_if_transform_transposed ─────────────────────────

    #[test]
    fn transpose_normal_no_swap() {
        assert_eq!(
            transpose_if_transform_transposed(Transform::Normal, 1920, 1080),
            (1920, 1080)
        );
    }

    #[test]
    fn transpose_90_swaps() {
        assert_eq!(
            transpose_if_transform_transposed(Transform::Normal90, 1920, 1080),
            (1080, 1920)
        );
    }

    #[test]
    fn transpose_180_no_swap() {
        assert_eq!(
            transpose_if_transform_transposed(Transform::Normal180, 1920, 1080),
            (1920, 1080)
        );
    }

    #[test]
    fn transpose_270_swaps() {
        assert_eq!(
            transpose_if_transform_transposed(Transform::Normal270, 1920, 1080),
            (1080, 1920)
        );
    }

    #[test]
    fn transpose_flipped_no_swap() {
        assert_eq!(
            transpose_if_transform_transposed(Transform::Flipped, 1920, 1080),
            (1920, 1080)
        );
    }

    #[test]
    fn transpose_flipped90_swaps() {
        assert_eq!(
            transpose_if_transform_transposed(Transform::Flipped90, 1920, 1080),
            (1080, 1920)
        );
    }

    #[test]
    fn transpose_flipped180_no_swap() {
        assert_eq!(
            transpose_if_transform_transposed(Transform::Flipped180, 1920, 1080),
            (1920, 1080)
        );
    }

    #[test]
    fn transpose_flipped270_swaps() {
        assert_eq!(
            transpose_if_transform_transposed(Transform::Flipped270, 1920, 1080),
            (1080, 1920)
        );
    }
}