const std = @import("std");
const Builder = std.build.Builder;

pub fn build(b: *Builder) void {
    const mode = b.standardReleaseOptions();

    const test_step = b.step("test", "Test");
    test_step.dependOn(b.getInstallStep());

    const lib = b.addSharedLibrary("lib", "lib.zig", .unversioned);
    lib.setBuildMode(mode);
    lib.setTarget(.{ .cpu_arch = .wasm32, .os_tag = .freestanding });
    lib.use_llvm = false;
    lib.use_stage1 = false;
    lib.use_lld = false;
    lib.strip = false;
    lib.stack_size = std.wasm.page_size * 2; // set an explicit stack size
    lib.install();

    const check_lib = lib.checkObject(.wasm);

    // ensure global exists and its initial value is equal to explitic stack size
    check_lib.checkStart("Section global");
    check_lib.checkNext("entries 1");
    check_lib.checkNext("type i32"); // on wasm32 the stack pointer must be i32
    check_lib.checkNext("mutable true"); // must be able to mutate the stack pointer
    check_lib.checkNext("i32.const {stack_pointer}");
    check_lib.checkComputeCompare("stack_pointer", .{ .op = .eq, .value = .{ .literal = lib.stack_size.? } });

    // validate memory section starts after virtual stack
    check_lib.checkNext("Section data");
    check_lib.checkNext("i32.const {data_start}");
    check_lib.checkComputeCompare("data_start", .{ .op = .eq, .value = .{ .variable = "stack_pointer" } });

    // validate the name of the stack pointer
    check_lib.checkStart("Section custom");
    check_lib.checkNext("type global");
    check_lib.checkNext("names 1");
    check_lib.checkNext("index 0");
    check_lib.checkNext("name __stack_pointer");
    test_step.dependOn(&check_lib.step);
}