const std = @import("std");
const sokol = @import("sokol");

const sg = sokol.gfx;

const shader = @import("shaders/triangle2.glsl.zig");

var pass_action: sg.PassAction = .{};

const state = struct {
    var bind: sg.Bindings = .{};
    var pip: sg.Pipeline = .{};
    var vsParams: shader.FsParams = .{ .offset = .{ 0, 0, 0 } };
    var indexCount: u16 = 0;
};

export fn init() void {
    sg.setup(.{
        .logger = .{ .func = sokol.log.func },
        .environment = sokol.glue.environment(),
    });

    sokol.time.setup();

    std.log.info("Vertex buffers len: {}", .{state.bind.vertex_buffers.len});

    var triangleVerts = [_]f32{
        // positions     colors
        0.0,  0.5,  0.5, 1.0, 0.0, 0.0, 1.0,
        0.5,  -0.5, 0.5, 0.0, 1.0, 0.0, 1.0,
        -0.5, -0.5, 0.5, 0.0, 0.0, 1.0, 1.0,
        0.7,  0.5,  0.5, 0.0, 1.0, 0.0, 1.0,
    };

    state.bind.vertex_buffers[0] = sg.makeBuffer(.{
        .data = sg.asRange(&triangleVerts),
    });

    const indexBuffer = [_]u16{
        0, 1, 2,
        0, 3, 1,
    };

    state.indexCount = indexBuffer.len;

    state.bind.index_buffer = sg.makeBuffer(.{
        .type = .INDEXBUFFER,
        .data = sg.asRange(&indexBuffer),
    });

    var pip_desc: sg.PipelineDesc = .{
        .index_type = .UINT16,
        .shader = sg.makeShader(shader.triangleShaderDesc(sg.queryBackend())),
    };

    pip_desc.layout.attrs[0].format = .FLOAT3;
    pip_desc.layout.attrs[1].format = .FLOAT4;

    state.pip = sg.makePipeline(pip_desc);

    pass_action.colors[0] = .{
        .load_action = .CLEAR,
        .clear_value = .{ .r = 0, .g = 1, .b = 0, .a = 1 },
    };

    std.log.info("Backend: {}\n", .{sg.queryBackend()});
}

fn timef() f32 {
    return @floatCast(sokol.time.sec(sokol.time.now()));
}

export fn frame() void {
    const col = &pass_action.colors[0].clear_value;
    col.g = @abs(@sin(timef()));
    col.r = @abs(@cos(timef()));

    sg.beginPass(.{ .action = pass_action, .swapchain = sokol.glue.swapchain() });
    sg.applyPipeline(state.pip);
    state.vsParams.offset[0] = col.r;
    sg.applyUniforms(.FS, shader.SLOT_fs_params, sg.asRange(&state.vsParams));
    sg.applyBindings(state.bind);
    sg.draw(0, state.indexCount, 1);
    sg.endPass();

    sg.commit();
}

export fn cleanup() void {}

pub fn main() !void {
    sokol.app.run(.{
        .init_cb = init,
        .frame_cb = frame,
        .cleanup_cb = cleanup,
        .width = 800,
        .height = 600,
        .icon = .{ .sokol_default = true },
        .window_title = "sokol hello",
        .logger = .{ .func = sokol.log.func },
    });
}