use crate::utils::try_hard_link;
use crate::SysrootKind;
use std::env;
use std::fs;
use std::path::Path;
use std::process::{self, Command};

pub(crate) fn build_sysroot(
    channel: &str,
    sysroot_kind: SysrootKind,
    target_dir: &Path,
    cg_clif_dylib: String,
    host_triple: &str,
    target_triple: &str,
) {
    if target_dir.exists() {
        fs::remove_dir_all(target_dir).unwrap();
    }
    fs::create_dir_all(target_dir.join("bin")).unwrap();
    fs::create_dir_all(target_dir.join("lib")).unwrap();

    // Copy the backend
    for file in ["cg_clif", "cg_clif_build_sysroot"] {
        try_hard_link(
            Path::new("target").join(channel).join(file),
            target_dir.join("bin").join(file),
        );
    }

    try_hard_link(
        Path::new("target").join(channel).join(&cg_clif_dylib),
        target_dir.join("lib").join(cg_clif_dylib),
    );

    // Copy supporting files
    try_hard_link("rust-toolchain", target_dir.join("rust-toolchain"));
    try_hard_link("scripts/config.sh", target_dir.join("config.sh"));
    try_hard_link("scripts/cargo.sh", target_dir.join("cargo.sh"));

    let default_sysroot = crate::rustc_info::get_default_sysroot();

    let rustlib = target_dir.join("lib").join("rustlib");
    let host_rustlib_lib = rustlib.join(host_triple).join("lib");
    let target_rustlib_lib = rustlib.join(target_triple).join("lib");
    fs::create_dir_all(&host_rustlib_lib).unwrap();
    fs::create_dir_all(&target_rustlib_lib).unwrap();

    if target_triple == "x86_64-pc-windows-gnu" {
        if !default_sysroot.join("lib").join("rustlib").join(target_triple).join("lib").exists() {
            eprintln!(
                "The x86_64-pc-windows-gnu target needs to be installed first before it is possible \
                to compile a sysroot for it.",
            );
            process::exit(1);
        }
        for file in fs::read_dir(
            default_sysroot.join("lib").join("rustlib").join(target_triple).join("lib"),
        )
        .unwrap()
        {
            let file = file.unwrap().path();
            if file.extension().map_or(true, |ext| ext.to_str().unwrap() != "o") {
                continue; // only copy object files
            }
            try_hard_link(&file, target_rustlib_lib.join(file.file_name().unwrap()));
        }
    }

    match sysroot_kind {
        SysrootKind::None => {} // Nothing to do
        SysrootKind::Llvm => {
            for file in fs::read_dir(
                default_sysroot.join("lib").join("rustlib").join(host_triple).join("lib"),
            )
            .unwrap()
            {
                let file = file.unwrap().path();
                let file_name_str = file.file_name().unwrap().to_str().unwrap();
                if file_name_str.contains("rustc_")
                    || file_name_str.contains("chalk")
                    || file_name_str.contains("tracing")
                    || file_name_str.contains("regex")
                {
                    // These are large crates that are part of the rustc-dev component and are not
                    // necessary to run regular programs.
                    continue;
                }
                try_hard_link(&file, host_rustlib_lib.join(file.file_name().unwrap()));
            }

            if target_triple != host_triple {
                for file in fs::read_dir(
                    default_sysroot.join("lib").join("rustlib").join(target_triple).join("lib"),
                )
                .unwrap()
                {
                    let file = file.unwrap().path();
                    try_hard_link(&file, target_rustlib_lib.join(file.file_name().unwrap()));
                }
            }
        }
        SysrootKind::Clif => {
            let cwd = env::current_dir().unwrap();

            let mut cmd = Command::new(cwd.join("build_sysroot").join("build_sysroot.sh"));
            cmd.current_dir(target_dir).env("TARGET_TRIPLE", target_triple);
            eprintln!("[BUILD] sysroot");
            if !cmd.spawn().unwrap().wait().unwrap().success() {
                process::exit(1);
            }

            if host_triple != target_triple {
                let mut cmd = Command::new(cwd.join("build_sysroot").join("build_sysroot.sh"));
                cmd.current_dir(target_dir).env("TARGET_TRIPLE", host_triple);
                eprintln!("[BUILD] sysroot");
                if !cmd.spawn().unwrap().wait().unwrap().success() {
                    process::exit(1);
                }
            }

            for file in fs::read_dir(host_rustlib_lib).unwrap() {
                let file = file.unwrap().path();
                if file.file_name().unwrap().to_str().unwrap().contains("std-") {
                    try_hard_link(&file, target_dir.join("lib").join(file.file_name().unwrap()));
                }
            }
        }
    }
}