//
// OMT module for zig
//
// Build required OMT parts and link against our code
//
// I don't know yet how to best create a conditional step to build and install
// the dependencies only if they aren't installed yet. Just putting the installs
// as dependencies runs the omt build scripts on every `zig build`.
//
const std = @import("std");

pub fn build(b: *std.Build) void {
    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});

    const triple = target.result;
    if (triple.os.tag != .linux or triple.cpu.arch != .x86_64) {
        std.log.warn("The build file only supports Linux x86-64 right now.\n", .{});
        std.log.warn(
            "You can extend the build.zig to call the appropriate platform scripts " ++
                "in 3rd/libomtnet/build/ and 3rd/libomt/build and 3rd/libvmx/build/ " ++
                "and modifying the install scripts",
            .{},
        );
        return;
    }

    // This path comes from the libomt build scripts
    const omt_out_path = "3rd/libomt/bin/Release/net8.0/linux-x64/publish/";
    const output_dir_path: std.Build.LazyPath = .{
        .src_path = .{
            .owner = b,
            .sub_path = omt_out_path,
        },
    };
    b.addNamedLazyPath("output_dir", output_dir_path);

    // The output lib and header directories
    const lib_output_path: std.Build.LazyPath = .{
        .cwd_relative = b.getInstallPath(.lib, ""),
    };
    const include_output_path: std.Build.LazyPath = .{
        .cwd_relative = b.getInstallPath(.header, ""),
    };

    std.debug.print("install-path: {s}\n", .{b.getInstallPath(.prefix, "")});
    std.debug.print("lib_output_path: {s}\n", .{lib_output_path.getDisplayName()});
    std.debug.print("include_output_path: {s}\n", .{include_output_path.getDisplayName()});

    // zomt module
    const omt_mod = b.addModule("zomt", .{
        .root_source_file = b.path("src/omt.zig"),
        .target = target,
        .optimize = optimize,
    });

    omt_mod.addLibraryPath(output_dir_path);
    omt_mod.addIncludePath(output_dir_path);
    omt_mod.linkSystemLibrary("omt", .{});

    // Build libomtnet
    const libomtnet_build_script = b.addSystemCommand(&.{"bash"});
    libomtnet_build_script.cwd = b.path("3rd/libomtnet/build");
    libomtnet_build_script.addFileArg(b.path("3rd/libomtnet/build/buildall.sh"));

    // Build libomt
    const libomt_build_script = b.addSystemCommand(&.{"bash"});
    libomt_build_script.cwd = b.path("3rd/libomt/build");
    libomt_build_script.addFileArg(b.path("3rd/libomt/build/buildlinuxx64.sh"));
    libomt_build_script.step.dependOn(&libomtnet_build_script.step);

    // Install libomt
    const install_omt_h = b.addInstallHeaderFile(
        b.path(b.pathJoin(&.{ omt_out_path, "libomt.h" })),
        "libomt.h",
    );
    install_omt_h.step.dependOn(&libomt_build_script.step);

    const install_omt_so = b.addInstallLibFile(
        b.path(b.pathJoin(&.{ omt_out_path, "libomt.so" })),
        "libomt.so",
    );
    install_omt_so.step.dependOn(&libomt_build_script.step);

    // Build libvmx
    const libvmx_build = b.addSystemCommand(&.{"bash"});
    libvmx_build.cwd = b.path("3rd/libvmx/build");
    libvmx_build.addFileArg(b.path("3rd/libvmx/build/buildlinuxx64.sh"));

    // Install libvmx
    const install_vmx_so = b.addInstallLibFile(
        b.path("3rd/libvmx/build/libvmx.so"),
        "libvmx.so",
    );
    install_vmx_so.step.dependOn(&libvmx_build.step);

    // Add object as dependency for module
    const libomtso_path = b.path(b.pathJoin(&.{ omt_out_path, "libomt.so" }));
    // Has no discernable effect atm
    omt_mod.addObjectFile(libomtso_path);

    {
        // Manual build step for libomt dependencies
        const build_omt_step = b.step("omt", "Build libomtnet, libomt and libvmx");
        build_omt_step.dependOn(&install_omt_h.step);
        build_omt_step.dependOn(&install_omt_so.step);
        build_omt_step.dependOn(&install_vmx_so.step);
    }

    // Test executables
    {
        // Define executables
        const sender_exe = b.addExecutable(.{
            .name = "sender",
            .root_module = b.createModule(.{
                .root_source_file = b.path("utils/sender.zig"),
                .target = target,
                .optimize = optimize,
            }),
        });
        sender_exe.root_module.addImport("omt", omt_mod);

        // These cause invocations for every zig build command, even tho it's not
        // usually needed, so prefer to use a manual step
        sender_exe.step.dependOn(&install_omt_h.step);
        sender_exe.step.dependOn(&install_omt_so.step);
        sender_exe.step.dependOn(&install_vmx_so.step);

        sender_exe.root_module.addLibraryPath(lib_output_path);
        sender_exe.root_module.addIncludePath(include_output_path);
        sender_exe.linkSystemLibrary("omt");
        sender_exe.linkLibC();

        b.installArtifact(sender_exe);
    }

    {
        const receiver_exe = b.addExecutable(.{
            .name = "receiver",
            .root_module = b.createModule(.{
                .root_source_file = b.path("utils/receiver.zig"),
                .target = target,
                .optimize = optimize,
            }),
        });
        receiver_exe.root_module.addImport("omt", omt_mod);

        // These cause invocations for every zig build command, even tho it's not
        // usually needed, so prefer to use a manual step
        receiver_exe.step.dependOn(&install_omt_h.step);
        receiver_exe.step.dependOn(&install_omt_so.step);
        receiver_exe.step.dependOn(&install_vmx_so.step);

        receiver_exe.root_module.addLibraryPath(lib_output_path);
        receiver_exe.root_module.addIncludePath(include_output_path);
        receiver_exe.linkSystemLibrary("omt");
        receiver_exe.linkLibC();

        b.installArtifact(receiver_exe);
    }
}