const std = @import("std");
const matrix = @import("matrix.zig");
const sdl = @import("sdl.zig");

const Cube = struct {
    points: [8][3]f32,
};

pub fn draw_cube(instance: sdl.instance, cube: Cube) void {
    var c = cube.points;
    sdl.draw_color(instance, 255, 255, 255, 0);
    sdl.draw_line(instance, &c[0], &c[1]);
    sdl.draw_line(instance, &c[0], &c[2]);
    sdl.draw_line(instance, &c[0], &c[4]);

    sdl.draw_line(instance, &c[7], &c[6]);
    sdl.draw_line(instance, &c[7], &c[5]);
    sdl.draw_line(instance, &c[7], &c[3]);

    sdl.draw_line(instance, &c[2], &c[3]);
    sdl.draw_line(instance, &c[4], &c[5]);
    sdl.draw_line(instance, &c[1], &c[5]);

    sdl.draw_line(instance, &c[6], &c[2]);
    sdl.draw_line(instance, &c[3], &c[1]);
    sdl.draw_line(instance, &c[4], &c[6]);
}

pub fn get_shifted_cube(cube: Cube, x: f32, y: f32, z: f32) Cube {
    var shifted_cube = Cube{ .points = undefined };
    for (cube.points) |point, i| {
        shifted_cube.points[i][0] = point[0] + x;
        shifted_cube.points[i][1] = point[1] + y;
        shifted_cube.points[i][2] = point[2] + z;
    }

    return shifted_cube;
}

pub fn get_centered_cube(cube: Cube, offset: f32) Cube {
    var centered_cube = Cube{ .points = undefined };
    for (cube.points) |point, i| {
        for (point) |dimension, j| {
            centered_cube.points[i][j] = dimension + offset;
        }
    }
    return centered_cube;
}

pub fn get_projected_cube(cube: Cube, alpha: f32, beta: f32) Cube {
    var projected_cube = Cube{ .points = undefined };

    var ax = [_]f32{
        1, 0,            0,
        0, @cos(alpha),  @sin(alpha),
        0, -@sin(alpha), @cos(alpha),
    };
    var a = matrix.new(3, 3, &ax);

    var bx = [_]f32{
        @cos(beta), 0, -@sin(beta),
        0,          1, 0,
        @sin(beta), 0, @cos(beta),
    };
    var b = matrix.new(3, 3, &bx);

    var cx = [_]f32{
        1, 0, 0,
        0, 1, 0,
        0, 0, 0,
    };
    var c = matrix.new(3, 3, &cx);

    for (cube.points) |point, i| {
        var p = point;
        var x = matrix.multiply(c, matrix.multiply(matrix.multiply(a, b), matrix.new(3, 1, &p))).x.items;
        projected_cube.points[i][0] = x[0];
        projected_cube.points[i][1] = x[1];
    }

    return projected_cube;
}

pub fn get_scaled_cube(cube: Cube, scale: f32) Cube {
    var scaled_cube = Cube{ .points = undefined };
    for (cube.points) |point, i| {
        for (point) |dimension, j| {
            scaled_cube.points[i][j] = dimension * scale;
        }
    }
    return scaled_cube;
}

pub fn main() anyerror!void {
    var instance = sdl.init();

    const unit_cube = Cube{
        .points = [8][3]f32{
            [3]f32{ 01, 01, 01 },
            [3]f32{ 01, 01, -1 },
            [3]f32{ 01, -1, 01 },
            [3]f32{ 01, -1, -1 },
            [3]f32{ -1, 01, 01 },
            [3]f32{ -1, 01, -1 },
            [3]f32{ -1, -1, 01 },
            [3]f32{ -1, -1, -1 },
        },
    };

    var beta: f32 = 0;
    var alpha: f32 = 0;
    while (true) {
        var event = sdl.get_event();
        if (event.mode == sdl.modes.quit) {
            break;
        } else if (event.mode == sdl.modes.key) {
            switch (event.key) {
                sdl.keys.q => break,
                else => continue,
            }
        }

        sdl.draw_color(instance, 0, 0, 0, 0);
        sdl.clear(instance);

        var cube = get_projected_cube(unit_cube, alpha, beta);
        cube = get_scaled_cube(cube, 50);
        cube = get_centered_cube(cube, 250);
        draw_cube(instance, cube);

        cube = get_projected_cube(unit_cube, alpha + 90, beta + 90);
        cube = get_scaled_cube(cube, 25);
        cube = get_centered_cube(cube, 250);
        draw_cube(instance, cube);

        cube = get_shifted_cube(unit_cube, 5, 0, 0);
        cube = get_projected_cube(cube, alpha, beta);
        cube = get_scaled_cube(cube, 25);
        cube = get_centered_cube(cube, 250);
        draw_cube(instance, cube);

        cube = get_shifted_cube(unit_cube, -5, 0, 0);
        cube = get_projected_cube(cube, alpha, beta);
        cube = get_scaled_cube(cube, 25);
        cube = get_centered_cube(cube, 250);
        draw_cube(instance, cube);

        beta += 0.01;
        alpha += 0.01;

        sdl.present(instance);
        sdl.delay(10);
    }

    sdl.quit(instance);
}