const Gfx = @import("./graphics.zig");

const Math = @import("lib").Math;
const Vec2 = Math.Vec2;
const Vec4 = Math.Vec4;
const rgb = Math.rgb;

const Lib = @import("lib");
const Frame = Lib.Frame;

const ScreenScalar = @This();

// TODO: Implement a fractional pixel perfect scalar
// Based on this video: https://www.youtube.com/watch?v=d6tp43wZqps
// And this blog: https://colececil.dev/blog/2017/scaling-pixel-art-without-destroying-it/

translation: Vec2,
scale: f32,

pub fn init(window_size: Vec2, canvas_size: Vec2) ScreenScalar {
    // TODO: Render to a lower resolution instead of scaling.
    // To avoid pixel bleeding in spritesheet artifacts
    const scale = @floor(@min(
        window_size.x / canvas_size.x,
        window_size.y / canvas_size.y,
    ));

    var translation: Vec2 = Vec2.sub(window_size, canvas_size.multiplyScalar(scale)).multiplyScalar(0.5);
    translation.x = @round(translation.x);
    translation.y = @round(translation.y);

    return ScreenScalar{
        .translation = translation,
        .scale = scale
    };
}

pub fn push(self: ScreenScalar, frame: *Frame) void {
    const scale = self.scale;
    const translation = self.translation;

    frame.pushTransform(translation, .init(scale, scale));
}

pub fn pop(self: ScreenScalar, frame: *Frame, color: Vec4) void {
    const translation = self.translation;

    frame.popTransform();

    frame.drawRectangle(.{
        .rect = .{
            .pos = .init(0, 0),
            .size = .init(frame.screen_size.x, translation.y),
        },
        .color = color
    });

    frame.drawRectangle(.{
        .rect = .{
            .pos = .init(0, frame.screen_size.y - translation.y),
            .size = .init(frame.screen_size.x, translation.y),
        },
        .color = color
    });

    frame.drawRectangle(.{
        .rect = .{
            .pos = .init(0, 0),
            .size = .init(translation.x, frame.screen_size.y),
        },
        .color = color
    });

    frame.drawRectangle(.{
        .rect = .{
            .pos = .init(frame.screen_size.x - translation.x, 0),
            .size = .init(translation.x, frame.screen_size.y),
        },
        .color = color
    });
}