//! Camera and input state management

/// GPU-compatible camera uniform data
#[repr(C)]
#[derive(Copy, Clone, Debug, bytemuck::Pod, bytemuck::Zeroable)]
pub struct CameraUniform {
    /// x: scale_x, y: scale_y, z: translate_x, w: translate_y
    pub params: [f32; 4],
    /// x: is_dark (1.0 for dark, 0.0 for light), y,z,w: padding
    pub theme: [f32; 4],
}

/// Camera state for 2D map view
pub struct Camera {
    pub x: f32,
    pub y: f32,
    pub zoom: f32,
    pub aspect: f32,
}

impl Camera {
    pub fn to_uniform(&self, is_dark: bool) -> CameraUniform {
        // Simple 2D orthographic projection-like transform
        // We want to map world coordinates to clip space [-1, 1]
        // zoom controls how much of the world we see.
        // aspect ratio correction is needed for non-square windows.
        
        // Scale:
        // If zoom is 1.0, we see 2.0 units of world height (from -1 to 1).
        // scale_y = zoom
        // scale_x = zoom / aspect
        
        CameraUniform {
            params: [
                self.zoom / self.aspect, // scale_x
                -self.zoom,              // scale_y (flipped for North-Up)
                -self.x * (self.zoom / self.aspect), // translate_x
                self.y * self.zoom,      // translate_y (flipped sign)
            ],
            theme: [
                if is_dark { 1.0 } else { 0.0 },
                0.0, 0.0, 0.0
            ],
        }
    }
}

/// Mouse/touch input state for drag operations
pub struct InputState {
    pub is_dragging: bool,
    pub last_cursor: Option<(f64, f64)>,
}