use crate::build;
use crate::config::{Channel, ConfigInfo};
use crate::utils::{
    get_toolchain, git_clone, git_clone_root_dir, remove_file, run_command, run_command_with_env,
    run_command_with_output_and_env, rustc_version_info, split_args, walk_dir,
};

use std::collections::{BTreeSet, HashMap};
use std::ffi::OsStr;
use std::fs::{create_dir_all, remove_dir_all, File};
use std::io::{BufRead, BufReader};
use std::path::{Path, PathBuf};
use std::str::FromStr;

type Env = HashMap<String, String>;
type Runner = fn(&Env, &TestArg) -> Result<(), String>;
type Runners = HashMap<&'static str, (&'static str, Runner)>;

fn get_runners() -> Runners {
    let mut runners = HashMap::new();

    runners.insert(
        "--test-rustc",
        ("Run all rustc tests", test_rustc as Runner),
    );
    runners.insert(
        "--test-successful-rustc",
        ("Run successful rustc tests", test_successful_rustc),
    );
    runners.insert(
        "--test-failing-rustc",
        ("Run failing rustc tests", test_failing_rustc),
    );
    runners.insert(
        "--projects",
        ("Run the tests of popular crates", test_projects),
    );
    runners.insert("--test-libcore", ("Run libcore tests", test_libcore));
    runners.insert("--clean", ("Empty cargo target directory", clean));
    runners.insert("--build-sysroot", ("Build sysroot", build_sysroot));
    runners.insert("--std-tests", ("Run std tests", std_tests));
    runners.insert("--asm-tests", ("Run asm tests", asm_tests));
    runners.insert(
        "--extended-tests",
        ("Run extended sysroot tests", extended_sysroot_tests),
    );
    runners.insert(
        "--extended-rand-tests",
        ("Run extended rand tests", extended_rand_tests),
    );
    runners.insert(
        "--extended-regex-example-tests",
        (
            "Run extended regex example tests",
            extended_regex_example_tests,
        ),
    );
    runners.insert(
        "--extended-regex-tests",
        ("Run extended regex tests", extended_regex_tests),
    );
    runners.insert("--mini-tests", ("Run mini tests", mini_tests));

    runners
}

fn get_number_after_arg(
    args: &mut impl Iterator<Item = String>,
    option: &str,
) -> Result<usize, String> {
    match args.next() {
        Some(nb) if !nb.is_empty() => match usize::from_str(&nb) {
            Ok(nb) => Ok(nb),
            Err(_) => Err(format!(
                "Expected a number after `{}`, found `{}`",
                option, nb
            )),
        },
        _ => Err(format!(
            "Expected a number after `{}`, found nothing",
            option
        )),
    }
}

fn show_usage() {
    println!(
        r#"
`test` command help:

    --release              : Build codegen in release mode
    --sysroot-panic-abort  : Build the sysroot without unwinding support.
    --features [arg]       : Add a new feature [arg]
    --use-system-gcc       : Use system installed libgccjit
    --build-only           : Only build rustc_codegen_gcc then exits
    --nb-parts             : Used to split rustc_tests (for CI needs)
    --current-part         : Used with `--nb-parts`, allows you to specify which parts to test"#
    );
    ConfigInfo::show_usage();
    for (option, (doc, _)) in get_runners() {
        // FIXME: Instead of using the hard-coded `23` value, better to compute it instead.
        let needed_spaces = 23_usize.saturating_sub(option.len());
        let spaces: String = std::iter::repeat(' ').take(needed_spaces).collect();
        println!("    {}{}: {}", option, spaces, doc);
    }
    println!("    --help                 : Show this help");
}

#[derive(Default, Debug)]
struct TestArg {
    build_only: bool,
    use_system_gcc: bool,
    runners: BTreeSet<String>,
    flags: Vec<String>,
    nb_parts: Option<usize>,
    current_part: Option<usize>,
    sysroot_panic_abort: bool,
    config_info: ConfigInfo,
}

impl TestArg {
    fn new() -> Result<Option<Self>, String> {
        let mut test_arg = Self::default();

        // We skip binary name and the `test` command.
        let mut args = std::env::args().skip(2);
        let runners = get_runners();

        while let Some(arg) = args.next() {
            match arg.as_str() {
                "--features" => match args.next() {
                    Some(feature) if !feature.is_empty() => {
                        test_arg
                            .flags
                            .extend_from_slice(&["--features".into(), feature]);
                    }
                    _ => {
                        return Err("Expected an argument after `--features`, found nothing".into())
                    }
                },
                "--use-system-gcc" => {
                    println!("Using system GCC");
                    test_arg.use_system_gcc = true;
                }
                "--build-only" => test_arg.build_only = true,
                "--nb-parts" => {
                    test_arg.nb_parts = Some(get_number_after_arg(&mut args, "--nb-parts")?);
                }
                "--current-part" => {
                    test_arg.current_part =
                        Some(get_number_after_arg(&mut args, "--current-part")?);
                }
                "--sysroot-panic-abort" => {
                    test_arg.sysroot_panic_abort = true;
                }
                "--help" => {
                    show_usage();
                    return Ok(None);
                }
                x if runners.contains_key(x) => {
                    test_arg.runners.insert(x.into());
                }
                arg => {
                    if !test_arg.config_info.parse_argument(arg, &mut args)? {
                        return Err(format!("Unknown option {}", arg));
                    }
                }
            }
        }
        match (test_arg.current_part, test_arg.nb_parts) {
            (Some(_), Some(_)) | (None, None) => {}
            _ => {
                return Err(
                    "If either `--current-part` or `--nb-parts` is specified, the other one \
                            needs to be specified as well!"
                        .to_string(),
                );
            }
        }
        if test_arg.config_info.no_default_features {
            test_arg.flags.push("--no-default-features".into());
        }
        Ok(Some(test_arg))
    }

    pub fn is_using_gcc_master_branch(&self) -> bool {
        !self.config_info.no_default_features
    }
}

fn build_if_no_backend(env: &Env, args: &TestArg) -> Result<(), String> {
    if args.config_info.backend.is_some() {
        return Ok(());
    }
    let mut command: Vec<&dyn AsRef<OsStr>> = vec![&"cargo", &"rustc"];
    let mut tmp_env;
    let env = if args.config_info.channel == Channel::Release {
        tmp_env = env.clone();
        tmp_env.insert("CARGO_INCREMENTAL".to_string(), "1".to_string());
        command.push(&"--release");
        &tmp_env
    } else {
        &env
    };
    for flag in args.flags.iter() {
        command.push(flag);
    }
    run_command_with_output_and_env(&command, None, Some(env))
}

fn clean(_env: &Env, args: &TestArg) -> Result<(), String> {
    let _ = std::fs::remove_dir_all(&args.config_info.cargo_target_dir);
    let path = Path::new(&args.config_info.cargo_target_dir).join("gccjit");
    std::fs::create_dir_all(&path)
        .map_err(|error| format!("failed to create folder `{}`: {:?}", path.display(), error))
}

fn mini_tests(env: &Env, args: &TestArg) -> Result<(), String> {
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[BUILD] mini_core");
    let crate_types = if args.config_info.host_triple != args.config_info.target_triple {
        "lib"
    } else {
        "lib,dylib"
    }
    .to_string();
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/mini_core.rs",
        &"--crate-name",
        &"mini_core",
        &"--crate-type",
        &crate_types,
        &"--target",
        &args.config_info.target_triple,
    ]);
    run_command_with_output_and_env(&command, None, Some(&env))?;

    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[BUILD] example");
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/example.rs",
        &"--crate-type",
        &"lib",
        &"--target",
        &args.config_info.target_triple,
    ]);
    run_command_with_output_and_env(&command, None, Some(&env))?;

    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[AOT] mini_core_hello_world");
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/mini_core_hello_world.rs",
        &"--crate-name",
        &"mini_core_hello_world",
        &"--crate-type",
        &"bin",
        &"-g",
        &"--target",
        &args.config_info.target_triple,
    ]);
    run_command_with_output_and_env(&command, None, Some(&env))?;

    let command: &[&dyn AsRef<OsStr>] = &[
        &Path::new(&args.config_info.cargo_target_dir).join("mini_core_hello_world"),
        &"abc",
        &"bcd",
    ];
    maybe_run_command_in_vm(&command, env, args)?;
    Ok(())
}

fn build_sysroot(env: &Env, args: &TestArg) -> Result<(), String> {
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[BUILD] sysroot");
    build::build_sysroot(env, &args.config_info)?;
    Ok(())
}

// TODO(GuillaumeGomez): when rewriting in Rust, refactor with the code in tests/lang_tests_common.rs if possible.
fn maybe_run_command_in_vm(
    command: &[&dyn AsRef<OsStr>],
    env: &Env,
    args: &TestArg,
) -> Result<(), String> {
    if !args.config_info.run_in_vm {
        run_command_with_output_and_env(command, None, Some(env))?;
        return Ok(());
    }
    let vm_parent_dir = match env.get("CG_GCC_VM_DIR") {
        Some(dir) if !dir.is_empty() => PathBuf::from(dir.clone()),
        _ => std::env::current_dir().unwrap(),
    };
    let vm_dir = "vm";
    let exe_to_run = command.first().unwrap();
    let exe = Path::new(&exe_to_run);
    let exe_filename = exe.file_name().unwrap();
    let vm_home_dir = vm_parent_dir.join(vm_dir).join("home");
    let vm_exe_path = vm_home_dir.join(exe_filename);
    let inside_vm_exe_path = Path::new("/home").join(exe_filename);

    let sudo_command: &[&dyn AsRef<OsStr>] = &[&"sudo", &"cp", &exe, &vm_exe_path];
    run_command_with_env(sudo_command, None, Some(env))?;

    let mut vm_command: Vec<&dyn AsRef<OsStr>> = vec![
        &"sudo",
        &"chroot",
        &vm_dir,
        &"qemu-m68k-static",
        &inside_vm_exe_path,
    ];
    vm_command.extend_from_slice(command);
    run_command_with_output_and_env(&vm_command, Some(&vm_parent_dir), Some(env))?;
    Ok(())
}

fn std_tests(env: &Env, args: &TestArg) -> Result<(), String> {
    let cargo_target_dir = Path::new(&args.config_info.cargo_target_dir);
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[AOT] arbitrary_self_types_pointers_and_wrappers");
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/arbitrary_self_types_pointers_and_wrappers.rs",
        &"--crate-name",
        &"arbitrary_self_types_pointers_and_wrappers",
        &"--crate-type",
        &"bin",
        &"--target",
        &args.config_info.target_triple,
    ]);
    run_command_with_env(&command, None, Some(env))?;
    maybe_run_command_in_vm(
        &[&cargo_target_dir.join("arbitrary_self_types_pointers_and_wrappers")],
        env,
        args,
    )?;

    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[AOT] alloc_system");
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/alloc_system.rs",
        &"--crate-type",
        &"lib",
        &"--target",
        &args.config_info.target_triple,
    ]);
    if args.is_using_gcc_master_branch() {
        command.extend_from_slice(&[&"--cfg", &"feature=\"master\""]);
    }
    run_command_with_env(&command, None, Some(env))?;

    // FIXME: doesn't work on m68k.
    if args.config_info.host_triple == args.config_info.target_triple {
        // FIXME: create a function "display_if_not_quiet" or something along the line.
        println!("[AOT] alloc_example");
        let mut command = args.config_info.rustc_command_vec();
        command.extend_from_slice(&[
            &"example/alloc_example.rs",
            &"--crate-type",
            &"bin",
            &"--target",
            &args.config_info.target_triple,
        ]);
        run_command_with_env(&command, None, Some(env))?;
        maybe_run_command_in_vm(&[&cargo_target_dir.join("alloc_example")], env, args)?;
    }

    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[AOT] dst_field_align");
    // FIXME(antoyo): Re-add -Zmir-opt-level=2 once rust-lang/rust#67529 is fixed.
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/dst-field-align.rs",
        &"--crate-name",
        &"dst_field_align",
        &"--crate-type",
        &"bin",
        &"--target",
        &args.config_info.target_triple,
    ]);
    run_command_with_env(&command, None, Some(env))?;
    maybe_run_command_in_vm(&[&cargo_target_dir.join("dst_field_align")], env, args)?;

    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[AOT] std_example");
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/std_example.rs",
        &"--crate-type",
        &"bin",
        &"--target",
        &args.config_info.target_triple,
    ]);
    if args.is_using_gcc_master_branch() {
        command.extend_from_slice(&[&"--cfg", &"feature=\"master\""]);
    }
    run_command_with_env(&command, None, Some(env))?;
    maybe_run_command_in_vm(
        &[
            &cargo_target_dir.join("std_example"),
            &"--target",
            &args.config_info.target_triple,
        ],
        env,
        args,
    )?;

    let test_flags = if let Some(test_flags) = env.get("TEST_FLAGS") {
        split_args(test_flags)?
    } else {
        Vec::new()
    };
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[AOT] subslice-patterns-const-eval");
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/subslice-patterns-const-eval.rs",
        &"--crate-type",
        &"bin",
        &"--target",
        &args.config_info.target_triple,
    ]);
    for test_flag in &test_flags {
        command.push(test_flag);
    }
    run_command_with_env(&command, None, Some(env))?;
    maybe_run_command_in_vm(
        &[&cargo_target_dir.join("subslice-patterns-const-eval")],
        env,
        args,
    )?;

    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[AOT] track-caller-attribute");
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/track-caller-attribute.rs",
        &"--crate-type",
        &"bin",
        &"--target",
        &args.config_info.target_triple,
    ]);
    for test_flag in &test_flags {
        command.push(test_flag);
    }
    run_command_with_env(&command, None, Some(env))?;
    maybe_run_command_in_vm(
        &[&cargo_target_dir.join("track-caller-attribute")],
        env,
        args,
    )?;

    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[AOT] mod_bench");
    let mut command = args.config_info.rustc_command_vec();
    command.extend_from_slice(&[
        &"example/mod_bench.rs",
        &"--crate-type",
        &"bin",
        &"--target",
        &args.config_info.target_triple,
    ]);
    run_command_with_env(&command, None, Some(env))?;
    // FIXME: the compiled binary is not run.

    Ok(())
}

fn setup_rustc(env: &mut Env, args: &TestArg) -> Result<PathBuf, String> {
    let toolchain = format!(
        "+{channel}-{host}",
        channel = get_toolchain()?, // May also include date
        host = args.config_info.host_triple
    );
    let rust_dir_path = Path::new(crate::BUILD_DIR).join("rust");
    // If the repository was already cloned, command will fail, so doesn't matter.
    let _ = git_clone(
        "https://github.com/rust-lang/rust.git",
        Some(&rust_dir_path),
        false,
    );
    let rust_dir: Option<&Path> = Some(&rust_dir_path);
    run_command(&[&"git", &"checkout", &"--", &"tests/"], rust_dir)?;
    run_command_with_output_and_env(&[&"git", &"fetch"], rust_dir, Some(env))?;
    let rustc_commit = match rustc_version_info(env.get("RUSTC").map(|s| s.as_str()))?.commit_hash {
        Some(commit_hash) => commit_hash,
        None => return Err("Couldn't retrieve rustc commit hash".to_string()),
    };
    if rustc_commit != "unknown" {
        run_command_with_output_and_env(
            &[&"git", &"checkout", &rustc_commit],
            rust_dir,
            Some(env),
        )?;
    } else {
        run_command_with_output_and_env(&[&"git", &"checkout"], rust_dir, Some(env))?;
    }
    let cargo = String::from_utf8(
        run_command_with_env(&[&"rustup", &"which", &"cargo"], rust_dir, Some(env))?.stdout,
    )
    .map_err(|error| format!("Failed to retrieve cargo path: {:?}", error))
    .and_then(|cargo| {
        let cargo = cargo.trim().to_owned();
        if cargo.is_empty() {
            Err(format!("`cargo` path is empty"))
        } else {
            Ok(cargo)
        }
    })?;
    let rustc = String::from_utf8(
        run_command_with_env(
            &[&"rustup", &toolchain, &"which", &"rustc"],
            rust_dir,
            Some(env),
        )?
        .stdout,
    )
    .map_err(|error| format!("Failed to retrieve rustc path: {:?}", error))
    .and_then(|rustc| {
        let rustc = rustc.trim().to_owned();
        if rustc.is_empty() {
            Err(format!("`rustc` path is empty"))
        } else {
            Ok(rustc)
        }
    })?;
    let llvm_filecheck = match run_command_with_env(
        &[
            &"bash",
            &"-c",
            &"which FileCheck-10 || \
          which FileCheck-11 || \
          which FileCheck-12 || \
          which FileCheck-13 || \
          which FileCheck-14",
        ],
        rust_dir,
        Some(env),
    ) {
        Ok(cmd) => String::from_utf8_lossy(&cmd.stdout).to_string(),
        Err(_) => {
            eprintln!("Failed to retrieve LLVM FileCheck, ignoring...");
            String::new()
        }
    };
    let file_path = rust_dir_path.join("config.toml");
    std::fs::write(
        &file_path,
        &format!(
            r#"change-id = 115898

[rust]
codegen-backends = []
deny-warnings = false
verbose-tests = true

[build]
cargo = "{cargo}"
local-rebuild = true
rustc = "{rustc}"

[target.x86_64-unknown-linux-gnu]
llvm-filecheck = "{llvm_filecheck}"

[llvm]
download-ci-llvm = false
"#,
            cargo = cargo,
            rustc = rustc,
            llvm_filecheck = llvm_filecheck.trim(),
        ),
    )
    .map_err(|error| {
        format!(
            "Failed to write into `{}`: {:?}",
            file_path.display(),
            error
        )
    })?;
    Ok(rust_dir_path)
}

fn asm_tests(env: &Env, args: &TestArg) -> Result<(), String> {
    let mut env = env.clone();
    let rust_dir = setup_rustc(&mut env, args)?;
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[TEST] rustc asm test suite");

    env.insert("COMPILETEST_FORCE_STAGE0".to_string(), "1".to_string());

    let extra = if args.is_using_gcc_master_branch() {
        ""
    } else {
        " -Csymbol-mangling-version=v0"
    };

    let rustc_args = &format!(
        r#"-Zpanic-abort-tests \
            -Zcodegen-backend="{pwd}/target/{channel}/librustc_codegen_gcc.{dylib_ext}" \
            --sysroot "{pwd}/build_sysroot/sysroot" -Cpanic=abort{extra}"#,
        pwd = std::env::current_dir()
            .map_err(|error| format!("`current_dir` failed: {:?}", error))?
            .display(),
        channel = args.config_info.channel.as_str(),
        dylib_ext = args.config_info.dylib_ext,
        extra = extra,
    );

    run_command_with_env(
        &[
            &"./x.py",
            &"test",
            &"--run",
            &"always",
            &"--stage",
            &"0",
            &"tests/assembly/asm",
            &"--rustc-args",
            &rustc_args,
        ],
        Some(&rust_dir),
        Some(&env),
    )?;
    Ok(())
}

fn run_cargo_command(
    command: &[&dyn AsRef<OsStr>],
    cwd: Option<&Path>,
    env: &Env,
    args: &TestArg,
) -> Result<(), String> {
    run_cargo_command_with_callback(command, cwd, env, args, |cargo_command, cwd, env| {
        run_command_with_output_and_env(cargo_command, cwd, Some(env))?;
        Ok(())
    })
}

fn run_cargo_command_with_callback<F>(
    command: &[&dyn AsRef<OsStr>],
    cwd: Option<&Path>,
    env: &Env,
    args: &TestArg,
    callback: F,
) -> Result<(), String>
where
    F: Fn(&[&dyn AsRef<OsStr>], Option<&Path>, &Env) -> Result<(), String>,
{
    let toolchain = get_toolchain()?;
    let toolchain_arg = format!("+{}", toolchain);
    let rustc_version = String::from_utf8(
        run_command_with_env(&[&args.config_info.rustc_command[0], &"-V"], cwd, Some(env))?.stdout,
    )
    .map_err(|error| format!("Failed to retrieve rustc version: {:?}", error))?;
    let rustc_toolchain_version = String::from_utf8(
        run_command_with_env(
            &[&args.config_info.rustc_command[0], &toolchain_arg, &"-V"],
            cwd,
            Some(env),
        )?
        .stdout,
    )
    .map_err(|error| format!("Failed to retrieve rustc +toolchain version: {:?}", error))?;

    if rustc_version != rustc_toolchain_version {
        eprintln!(
            "rustc_codegen_gcc is built for `{}` but the default rustc version is `{}`.",
            rustc_toolchain_version, rustc_version,
        );
        eprintln!("Using `{}`.", rustc_toolchain_version);
    }
    let mut env = env.clone();
    let rustflags = env.get("RUSTFLAGS").cloned().unwrap_or_default();
    env.insert("RUSTDOCFLAGS".to_string(), rustflags);
    let mut cargo_command: Vec<&dyn AsRef<OsStr>> = vec![&"cargo", &toolchain_arg];
    cargo_command.extend_from_slice(&command);
    callback(&cargo_command, cwd, &env)
}

// FIXME(antoyo): linker gives multiple definitions error on Linux
// echo "[BUILD] sysroot in release mode"
// ./build_sysroot/build_sysroot.sh --release

fn test_projects(env: &Env, args: &TestArg) -> Result<(), String> {
    let projects = [
        //"https://gitlab.gnome.org/GNOME/librsvg", // FIXME: doesn't compile in the CI since the
        // version of cairo and other libraries is too old.
        "https://github.com/rust-random/getrandom",
        "https://github.com/BurntSushi/memchr",
        "https://github.com/dtolnay/itoa",
        "https://github.com/rust-lang/cfg-if",
        "https://github.com/rust-lang-nursery/lazy-static.rs",
        //"https://github.com/marshallpierce/rust-base64", // FIXME: one test is OOM-killed.
        // TODO: ignore the base64 test that is OOM-killed.
        "https://github.com/time-rs/time",
        "https://github.com/rust-lang/log",
        "https://github.com/bitflags/bitflags",
        //"https://github.com/serde-rs/serde", // FIXME: one test fails.
        //"https://github.com/rayon-rs/rayon", // TODO: very slow, only run on master?
        //"https://github.com/rust-lang/cargo", // TODO: very slow, only run on master?
    ];

    let run_tests = |projects_path, iter: &mut dyn Iterator<Item = &&str>| -> Result<(), String> {
        for project in iter {
            let clone_result = git_clone_root_dir(project, projects_path, true)?;
            let repo_path = Path::new(&clone_result.repo_dir);
            run_cargo_command(&[&"build", &"--release"], Some(repo_path), env, args)?;
            run_cargo_command(&[&"test"], Some(repo_path), env, args)?;
        }

        Ok(())
    };

    let projects_path = Path::new("projects");
    create_dir_all(projects_path)
        .map_err(|err| format!("Failed to create directory `projects`: {}", err))?;

    let nb_parts = args.nb_parts.unwrap_or(0);
    if nb_parts > 0 {
        // We increment the number of tests by one because if this is an odd number, we would skip
        // one test.
        let count = projects.len() / nb_parts + 1;
        let current_part = args.current_part.unwrap();
        let start = current_part * count;
        // We remove the projects we don't want to test.
        run_tests(projects_path, &mut projects.iter().skip(start).take(count))?;
    } else {
        run_tests(projects_path, &mut projects.iter())?;
    }

    Ok(())
}

fn test_libcore(env: &Env, args: &TestArg) -> Result<(), String> {
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[TEST] libcore");
    let path = Path::new("build_sysroot/sysroot_src/library/core/tests");
    let _ = remove_dir_all(path.join("target"));
    run_cargo_command(&[&"test"], Some(path), env, args)?;
    Ok(())
}

// echo "[BENCH COMPILE] mod_bench"
//
// COMPILE_MOD_BENCH_INLINE="$RUSTC example/mod_bench.rs --crate-type bin -Zmir-opt-level=3 -O --crate-name mod_bench_inline"
// COMPILE_MOD_BENCH_LLVM_0="rustc example/mod_bench.rs --crate-type bin -Copt-level=0 -o $cargo_target_dir/mod_bench_llvm_0 -Cpanic=abort"
// COMPILE_MOD_BENCH_LLVM_1="rustc example/mod_bench.rs --crate-type bin -Copt-level=1 -o $cargo_target_dir/mod_bench_llvm_1 -Cpanic=abort"
// COMPILE_MOD_BENCH_LLVM_2="rustc example/mod_bench.rs --crate-type bin -Copt-level=2 -o $cargo_target_dir/mod_bench_llvm_2 -Cpanic=abort"
// COMPILE_MOD_BENCH_LLVM_3="rustc example/mod_bench.rs --crate-type bin -Copt-level=3 -o $cargo_target_dir/mod_bench_llvm_3 -Cpanic=abort"
//
// Use 100 runs, because a single compilations doesn't take more than ~150ms, so it isn't very slow
// hyperfine --runs ${COMPILE_RUNS:-100} "$COMPILE_MOD_BENCH_INLINE" "$COMPILE_MOD_BENCH_LLVM_0" "$COMPILE_MOD_BENCH_LLVM_1" "$COMPILE_MOD_BENCH_LLVM_2" "$COMPILE_MOD_BENCH_LLVM_3"
// echo "[BENCH RUN] mod_bench"
// hyperfine --runs ${RUN_RUNS:-10} $cargo_target_dir/mod_bench{,_inline} $cargo_target_dir/mod_bench_llvm_*

fn extended_rand_tests(env: &Env, args: &TestArg) -> Result<(), String> {
    if !args.is_using_gcc_master_branch() {
        println!("Not using GCC master branch. Skipping `extended_rand_tests`.");
        return Ok(());
    }
    let mut env = env.clone();
    // newer aho_corasick versions throw a deprecation warning
    let rustflags = format!(
        "{} --cap-lints warn",
        env.get("RUSTFLAGS").cloned().unwrap_or_default()
    );
    env.insert("RUSTFLAGS".to_string(), rustflags);

    let path = Path::new(crate::BUILD_DIR).join("rand");
    run_cargo_command(&[&"clean"], Some(&path), &env, args)?;
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[TEST] rust-random/rand");
    run_cargo_command(&[&"test", &"--workspace"], Some(&path), &env, args)?;
    Ok(())
}

fn extended_regex_example_tests(env: &Env, args: &TestArg) -> Result<(), String> {
    if !args.is_using_gcc_master_branch() {
        println!("Not using GCC master branch. Skipping `extended_regex_example_tests`.");
        return Ok(());
    }
    let path = Path::new(crate::BUILD_DIR).join("regex");
    run_cargo_command(&[&"clean"], Some(&path), env, args)?;
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[TEST] rust-lang/regex example shootout-regex-dna");
    let mut env = env.clone();
    // newer aho_corasick versions throw a deprecation warning
    let rustflags = format!(
        "{} --cap-lints warn",
        env.get("RUSTFLAGS").cloned().unwrap_or_default()
    );
    env.insert("RUSTFLAGS".to_string(), rustflags);
    // Make sure `[codegen mono items] start` doesn't poison the diff
    run_cargo_command(
        &[&"build", &"--example", &"shootout-regex-dna"],
        Some(&path),
        &env,
        args,
    )?;

    run_cargo_command_with_callback(
        &[&"run", &"--example", &"shootout-regex-dna"],
        Some(&path),
        &env,
        args,
        |cargo_command, cwd, env| {
            // FIXME: rewrite this with `child.stdin.write_all()` because
            // `examples/regexdna-input.txt` is very small.
            let mut command: Vec<&dyn AsRef<OsStr>> = vec![&"bash", &"-c"];
            let cargo_args = cargo_command
                .iter()
                .map(|s| s.as_ref().to_str().unwrap())
                .collect::<Vec<_>>();
            let bash_command = format!(
                "cat examples/regexdna-input.txt | {} | grep -v 'Spawned thread' > res.txt",
                cargo_args.join(" "),
            );
            command.push(&bash_command);
            run_command_with_output_and_env(&command, cwd, Some(env))?;
            run_command_with_output_and_env(
                &[&"diff", &"-u", &"res.txt", &"examples/regexdna-output.txt"],
                cwd,
                Some(env),
            )?;
            Ok(())
        },
    )?;

    Ok(())
}

fn extended_regex_tests(env: &Env, args: &TestArg) -> Result<(), String> {
    if !args.is_using_gcc_master_branch() {
        println!("Not using GCC master branch. Skipping `extended_regex_tests`.");
        return Ok(());
    }
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[TEST] rust-lang/regex tests");
    let mut env = env.clone();
    // newer aho_corasick versions throw a deprecation warning
    let rustflags = format!(
        "{} --cap-lints warn",
        env.get("RUSTFLAGS").cloned().unwrap_or_default()
    );
    env.insert("RUSTFLAGS".to_string(), rustflags);
    let path = Path::new(crate::BUILD_DIR).join("regex");
    run_cargo_command(
        &[
            &"test",
            &"--tests",
            &"--",
            // FIXME: try removing `--exclude-should-panic` argument
            &"--exclude-should-panic",
            &"--test-threads",
            &"1",
            &"-Zunstable-options",
            &"-q",
        ],
        Some(&path),
        &env,
        args,
    )?;
    Ok(())
}

fn extended_sysroot_tests(env: &Env, args: &TestArg) -> Result<(), String> {
    // pushd simple-raytracer
    // echo "[BENCH COMPILE] ebobby/simple-raytracer"
    // hyperfine --runs "${RUN_RUNS:-10}" --warmup 1 --prepare "cargo clean" \
    // "RUSTC=rustc RUSTFLAGS='' cargo build" \
    // "../y.sh cargo build"

    // echo "[BENCH RUN] ebobby/simple-raytracer"
    // cp ./target/debug/main ./raytracer_cg_gcc
    // hyperfine --runs "${RUN_RUNS:-10}" ./raytracer_cg_llvm ./raytracer_cg_gcc
    // popd
    extended_rand_tests(env, args)?;
    extended_regex_example_tests(env, args)?;
    extended_regex_tests(env, args)?;

    Ok(())
}

fn should_not_remove_test(file: &str) -> bool {
    // contains //~ERROR, but shouldn't be removed
    [
        "issues/auxiliary/issue-3136-a.rs",
        "type-alias-impl-trait/auxiliary/cross_crate_ice.rs",
        "type-alias-impl-trait/auxiliary/cross_crate_ice2.rs",
        "macros/rfc-2011-nicer-assert-messages/auxiliary/common.rs",
        "imports/ambiguous-1.rs",
        "imports/ambiguous-4-extern.rs",
        "entry-point/auxiliary/bad_main_functions.rs",
    ]
    .iter()
    .any(|to_ignore| file.ends_with(to_ignore))
}

fn should_remove_test(file_path: &Path) -> Result<bool, String> {
    // Tests generating errors.
    let file = File::open(file_path)
        .map_err(|error| format!("Failed to read `{}`: {:?}", file_path.display(), error))?;
    for line in BufReader::new(file).lines().filter_map(|line| line.ok()) {
        let line = line.trim();
        if line.is_empty() {
            continue;
        }
        if [
            "//@ error-pattern:",
            "//@ build-fail",
            "//@ run-fail",
            "-Cllvm-args",
            "//~",
            "thread",
        ]
        .iter()
        .any(|check| line.contains(check))
        {
            return Ok(true);
        }
        if line.contains("//[") && line.contains("]~") {
            return Ok(true);
        }
    }
    if file_path
        .display()
        .to_string()
        .contains("ambiguous-4-extern.rs")
    {
        eprintln!("nothing found for {file_path:?}");
    }
    Ok(false)
}

fn test_rustc_inner<F>(env: &Env, args: &TestArg, prepare_files_callback: F) -> Result<(), String>
where
    F: Fn(&Path) -> Result<bool, String>,
{
    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[TEST] rust-lang/rust");
    let mut env = env.clone();
    let rust_path = setup_rustc(&mut env, args)?;

    walk_dir(
        rust_path.join("tests/ui"),
        |dir| {
            let dir_name = dir.file_name().and_then(|name| name.to_str()).unwrap_or("");
            if [
                "abi",
                "extern",
                "unsized-locals",
                "proc-macro",
                "threads-sendsync",
                "borrowck",
                "test-attrs",
            ]
            .iter()
            .any(|name| *name == dir_name)
            {
                std::fs::remove_dir_all(dir).map_err(|error| {
                    format!("Failed to remove folder `{}`: {:?}", dir.display(), error)
                })?;
            }
            Ok(())
        },
        |_| Ok(()),
    )?;

    // These two functions are used to remove files that are known to not be working currently
    // with the GCC backend to reduce noise.
    fn dir_handling(dir: &Path) -> Result<(), String> {
        if dir
            .file_name()
            .map(|name| name == "auxiliary")
            .unwrap_or(true)
        {
            return Ok(());
        }
        walk_dir(dir, dir_handling, file_handling)
    }
    fn file_handling(file_path: &Path) -> Result<(), String> {
        if !file_path
            .extension()
            .map(|extension| extension == "rs")
            .unwrap_or(false)
        {
            return Ok(());
        }
        let path_str = file_path.display().to_string().replace("\\", "/");
        if should_not_remove_test(&path_str) {
            return Ok(());
        } else if should_remove_test(file_path)? {
            return remove_file(&file_path);
        }
        Ok(())
    }

    remove_file(&rust_path.join("tests/ui/consts/const_cmp_type_id.rs"))?;
    remove_file(&rust_path.join("tests/ui/consts/issue-73976-monomorphic.rs"))?;
    // this test is oom-killed in the CI.
    remove_file(&rust_path.join("tests/ui/consts/issue-miri-1910.rs"))?;
    // Tests generating errors.
    remove_file(&rust_path.join("tests/ui/consts/issue-94675.rs"))?;
    remove_file(&rust_path.join("tests/ui/mir/mir_heavy_promoted.rs"))?;
    remove_file(&rust_path.join("tests/ui/rfcs/rfc-2632-const-trait-impl/const-drop-fail.rs"))?;
    remove_file(&rust_path.join("tests/ui/rfcs/rfc-2632-const-trait-impl/const-drop.rs"))?;

    walk_dir(rust_path.join("tests/ui"), dir_handling, file_handling)?;

    if !prepare_files_callback(&rust_path)? {
        // FIXME: create a function "display_if_not_quiet" or something along the line.
        println!("Keeping all UI tests");
    }

    let nb_parts = args.nb_parts.unwrap_or(0);
    if nb_parts > 0 {
        let current_part = args.current_part.unwrap();
        // FIXME: create a function "display_if_not_quiet" or something along the line.
        println!(
            "Splitting ui_test into {} parts (and running part {})",
            nb_parts, current_part
        );
        let out = String::from_utf8(
            run_command(
                &[
                    &"find",
                    &"tests/ui",
                    &"-type",
                    &"f",
                    &"-name",
                    &"*.rs",
                    &"-not",
                    &"-path",
                    &"*/auxiliary/*",
                ],
                Some(&rust_path),
            )?
            .stdout,
        )
        .map_err(|error| format!("Failed to retrieve output of find command: {:?}", error))?;
        let mut files = out
            .split('\n')
            .map(|line| line.trim())
            .filter(|line| !line.is_empty())
            .collect::<Vec<_>>();
        // To ensure it'll be always the same sub files, we sort the content.
        files.sort();
        // We increment the number of tests by one because if this is an odd number, we would skip
        // one test.
        let count = files.len() / nb_parts + 1;
        let start = current_part * count;
        // We remove the files we don't want to test.
        for path in files.iter().skip(start).take(count) {
            remove_file(&rust_path.join(path))?;
        }
    }

    // FIXME: create a function "display_if_not_quiet" or something along the line.
    println!("[TEST] rustc test suite");
    env.insert("COMPILETEST_FORCE_STAGE0".to_string(), "1".to_string());

    let extra = if args.is_using_gcc_master_branch() {
        ""
    } else {
        " -Csymbol-mangling-version=v0"
    };

    let rustc_args = format!(
        "{} -Zcodegen-backend={} --sysroot {}{}",
        env.get("TEST_FLAGS").unwrap_or(&String::new()),
        args.config_info.cg_backend_path,
        args.config_info.sysroot_path,
        extra,
    );

    env.get_mut("RUSTFLAGS").unwrap().clear();
    run_command_with_output_and_env(
        &[
            &"./x.py",
            &"test",
            &"--run",
            &"always",
            &"--stage",
            &"0",
            &"tests/ui",
            &"--rustc-args",
            &rustc_args,
        ],
        Some(&rust_path),
        Some(&env),
    )?;
    Ok(())
}

fn test_rustc(env: &Env, args: &TestArg) -> Result<(), String> {
    test_rustc_inner(env, args, |_| Ok(false))
}

fn test_failing_rustc(env: &Env, args: &TestArg) -> Result<(), String> {
    test_rustc_inner(env, args, |rust_path| {
        // Removing all tests.
        run_command(
            &[
                &"find",
                &"tests/ui",
                &"-type",
                &"f",
                &"-name",
                &"*.rs",
                &"-not",
                &"-path",
                &"*/auxiliary/*",
                &"-delete",
            ],
            Some(rust_path),
        )?;
        // Putting back only the failing ones.
        let path = "tests/failing-ui-tests.txt";
        if let Ok(files) = std::fs::read_to_string(path) {
            for file in files
                .split('\n')
                .map(|line| line.trim())
                .filter(|line| !line.is_empty())
            {
                run_command(&[&"git", &"checkout", &"--", &file], Some(&rust_path))?;
            }
        } else {
            println!(
                "Failed to read `{}`, not putting back failing ui tests",
                path
            );
        }
        Ok(true)
    })
}

fn test_successful_rustc(env: &Env, args: &TestArg) -> Result<(), String> {
    test_rustc_inner(env, args, |rust_path| {
        // Removing the failing tests.
        let path = "tests/failing-ui-tests.txt";
        if let Ok(files) = std::fs::read_to_string(path) {
            for file in files
                .split('\n')
                .map(|line| line.trim())
                .filter(|line| !line.is_empty())
            {
                let path = rust_path.join(file);
                remove_file(&path)?;
            }
        } else {
            println!(
                "Failed to read `{}`, not putting back failing ui tests",
                path
            );
        }
        Ok(true)
    })
}

fn run_all(env: &Env, args: &TestArg) -> Result<(), String> {
    clean(env, args)?;
    mini_tests(env, args)?;
    build_sysroot(env, args)?;
    std_tests(env, args)?;
    // asm_tests(env, args)?;
    test_libcore(env, args)?;
    extended_sysroot_tests(env, args)?;
    test_rustc(env, args)?;
    Ok(())
}

pub fn run() -> Result<(), String> {
    let mut args = match TestArg::new()? {
        Some(args) => args,
        None => return Ok(()),
    };
    let mut env: HashMap<String, String> = std::env::vars().collect();

    if !args.use_system_gcc {
        args.config_info.setup_gcc_path()?;
        env.insert(
            "LIBRARY_PATH".to_string(),
            args.config_info.gcc_path.clone(),
        );
        env.insert(
            "LD_LIBRARY_PATH".to_string(),
            args.config_info.gcc_path.clone(),
        );
    }

    build_if_no_backend(&env, &args)?;
    if args.build_only {
        println!("Since it's build only, exiting...");
        return Ok(());
    }

    args.config_info.setup(&mut env, args.use_system_gcc)?;

    if args.runners.is_empty() {
        run_all(&env, &args)?;
    } else {
        let runners = get_runners();
        for runner in args.runners.iter() {
            runners.get(runner.as_str()).unwrap().1(&env, &args)?;
        }
    }

    Ok(())
}