use std::path::Path;

use cmd_lib::*;
use eyre::{Result, WrapErr};
use paste::paste;

use super::*;
use cmake::Options;

fn config_llvm(global_cfg: &Global, llvm_cfg: &LlvmBuilder) -> Result<()> {
    // To reduce the need to clean CMakeCache.txt, all cmake vars for LLVM
    // are explicitly given defaults if they are optional in the cfg gile.
    let mut cmake_options = Options::new();
    let llvm_linker = llvm_cfg.llvm.linker.as_deref().unwrap_or(Path::new("ld"));
    let launcher = global_cfg.sccache.as_deref().unwrap_or(Path::new(""));
    let archs = llvm_cfg.archs.as_ref().map(|l| (l, ";"));
    let exp_archs = llvm_cfg.experimental_archs.as_ref().map(|l| (l, ";"));

    cmake_options.add("CMAKE_BUILD_TYPE", "RelWithDebInfo");
    cmake_options.add("CMAKE_INSTALL_PREFIX", &*global_cfg.prefix);
    cmake_options.add("LLVM_USE_LINKER", llvm_linker);
    cmake_options.add("CMAKE_C_COMPILER_LAUNCHER", launcher);
    cmake_options.add("CMAKE_CXX_COMPILER_LAUNCHER", launcher);
    cmake_options.add_or("LLVM_TARGETS_TO_BUILD", "all", archs);
    cmake_options.add_or("LLVM_EXPERIMENTAL_TARGETS_TO_BUILD", "", exp_archs);
    cmake_options.add("BUILD_SHARED_LIBS", llvm_cfg.llvm.shared);
    cmake_options.add("LLVM_ENABLE_ASSERTIONS", llvm_cfg.llvm.assertions);

    do_config(
        "llvm",
        cmake_options.collect()?,
        collect_path(&[&global_cfg.llvm_root.try_to_str()?, "llvm"]),
    )?;

    Ok(())
}

fn config_clang(global_cfg: &Global, llvm_cfg: &LlvmBuilder) -> Result<()> {
    let llvm_dir = if llvm_cfg.install {
        None
    } else {
        Some(collect_path(&[
            env::current_dir()?.try_to_str()?,
            "build-llvm",
            "lib",
            "cmake",
            "llvm",
        ]))
    };

    let mut cmake_options = Options::new();
    let llvm_dir = llvm_dir.as_deref().unwrap_or(Path::new(""));
    let llvm_linker = llvm_cfg.llvm.linker.as_deref().unwrap_or(Path::new("ld"));
    let launcher = global_cfg.sccache.as_deref().unwrap_or(Path::new(""));

    cmake_options.add("CMAKE_BUILD_TYPE", "Release");
    cmake_options.add("CMAKE_INSTALL_PREFIX", &*global_cfg.prefix);
    cmake_options.add("LLVM_DIR", llvm_dir);
    cmake_options.add("LLVM_USE_LINKER", llvm_linker);
    cmake_options.add("CMAKE_C_COMPILER_LAUNCHER", launcher);
    cmake_options.add("CMAKE_CXX_COMPILER_LAUNCHER", launcher);

    do_config(
        "clang",
        cmake_options.collect()?,
        collect_path(&[&global_cfg.llvm_root.try_to_str()?, "clang"]),
    )?;

    Ok(())
}

fn config_lld(global_cfg: &Global, llvm_cfg: &LlvmBuilder) -> Result<()> {
    let llvm_dir = if llvm_cfg.install {
        None
    } else {
        Some(collect_path(&[
            env::current_dir()?.try_to_str()?,
            "build-llvm",
            "lib",
            "cmake",
            "llvm",
        ]))
    };

    let mut cmake_options = Options::new();
    let llvm_dir = llvm_dir.as_deref().unwrap_or(Path::new(""));
    let llvm_linker = llvm_cfg.llvm.linker.as_deref().unwrap_or(Path::new("ld"));
    let launcher = global_cfg.sccache.as_deref().unwrap_or(Path::new(""));

    cmake_options.add("CMAKE_BUILD_TYPE", "Release");
    cmake_options.add("CMAKE_INSTALL_PREFIX", &*global_cfg.prefix);
    cmake_options.add("LLVM_DIR", llvm_dir);
    cmake_options.add("LLVM_USE_LINKER", llvm_linker);
    cmake_options.add("CMAKE_C_COMPILER_LAUNCHER", launcher);
    cmake_options.add("CMAKE_CXX_COMPILER_LAUNCHER", launcher);

    do_config(
        "lld",
        cmake_options.collect()?,
        collect_path(&[&global_cfg.llvm_root.try_to_str()?, "lld"]),
    )?;

    Ok(())
}

fn do_config(t: &str, cmake_options: Vec<OsString>, src_root: PathBuf) -> Result<()> {
    run_cmd!(
        mkdir -p build-$t;
        cd build-$t;
        cmake -G "Ninja" $[cmake_options] $src_root;
    )
    .wrap_err("could not build toolchain")
}

fn do_build(t: &str, _global_cfg: &Global, llvm_cfg: &LlvmBuilder, _mode: &BuildMode) -> Result<()> {
    run_cmd!(
        cd build-$t;
        ninja -j8;
    )?;

    if llvm_cfg.install {
        run_cmd!(
            cd build-$t;
            ninja install;
        )?;
    }

    Ok(())
}

macro_rules! build_function {
    ($t:ident) => {
        paste! {
            pub fn [<build_ $t>](global_cfg: &Global, llvm_cfg: &LlvmBuilder, mode: &BuildMode) -> Result<()> {
                if !mode.no_config {
                    [<config_ $t>](global_cfg, llvm_cfg)?;
                }

                if !mode.no_build {
                    do_build(stringify!($t), global_cfg, llvm_cfg, mode)?;
                }

                Ok(())
            }
        }
    }
}

use build_function;

build_function!(llvm);
build_function!(clang);
build_function!(lld);