//! Shared fixture copies and builds. A mutex protects cwd-init and the shell build.
use std::{
    hash::{Hash, Hasher},
    os::unix::{ffi::OsStrExt, fs::PermissionsExt},
    path::{Path, PathBuf},
    process::{Command, ExitStatus},
    sync::{Mutex, OnceLock},
};
pub static BUILD: Mutex<()> = Mutex::new(());

pub fn runtime_options() -> sausage::process::RuntimeOptions {
    sausage::process::RuntimeOptions {
        no_builder_sandbox: std::env::var("SAUSAGE_TEST_NO_BUILDER_SANDBOX").as_deref() == Ok("1"),
    }
}

/// Keep the real shared prompt in every roster fixture, with an ephemeral approval port.
pub fn write_config(
    dir: &Path,
    main_agent_name: &str,
    roster: serde_json::Value,
) -> anyhow::Result<()> {
    let mut config: serde_json::Value =
        serde_yaml_ng::from_str(include_str!("../../../config/config.yaml"))?;
    config["main_agent_name"] = serde_json::json!(main_agent_name);
    let folder = dir.join("world/etc/sausage");
    std::fs::create_dir_all(folder.join("roster"))?;
    for entry in roster.as_array().unwrap() {
        let mut fields = entry.as_object().unwrap().clone();
        let name = fields.remove("name").unwrap().as_str().unwrap().to_owned();
        let prompt = fields
            .remove("prompt")
            .unwrap()
            .as_str()
            .unwrap()
            .to_owned();
        std::fs::write(
            folder.join("roster").join(format!("{name}.md")),
            format!(
                "---\n{}---\n\n{prompt}\n",
                serde_yaml_ng::to_string(&fields)?
            ),
        )?;
    }
    std::fs::write(
        folder.join("config.yaml"),
        serde_yaml_ng::to_string(&config)?,
    )?;
    Ok(())
}

pub fn copy_tree(source: &Path, destination: &Path) -> anyhow::Result<()> {
    std::fs::create_dir_all(destination)?;
    for entry in std::fs::read_dir(source)? {
        let entry = entry?;
        let target = destination.join(entry.file_name());
        if entry.file_type()?.is_dir() {
            copy_tree(&entry.path(), &target)?;
        } else {
            std::fs::copy(entry.path(), target)?;
        }
    }
    Ok(())
}

pub fn target_dir() -> PathBuf {
    std::env::var_os("CARGO_TARGET_DIR")
        .map(PathBuf::from)
        .unwrap_or_else(|| {
            Path::new(env!("CARGO_TARGET_TMPDIR"))
                .parent()
                .unwrap()
                .to_owned()
        })
}

/// Fingerprint the snapshot inputs and their current working-tree contents.
pub fn bundle_key(repo: &Path) -> anyhow::Result<String> {
    const INPUTS: &[&str] = &[
        "host",
        "vfs",
        "userland",
        "config",
        "skills",
        "extensions",
        "Cargo.toml",
        "Cargo.lock",
        "flake.nix",
        "flake.lock",
        "README.md",
        "AGENTS.md",
        ".gitignore",
    ];
    let tree = Command::new("git")
        .current_dir(repo)
        .args(["ls-tree", "HEAD", "--"])
        .args(INPUTS)
        .output()?;
    anyhow::ensure!(
        tree.status.success(),
        "git ls-tree: {}",
        String::from_utf8_lossy(&tree.stderr)
    );
    let files = Command::new("git")
        .current_dir(repo)
        .args([
            "ls-files",
            "-z",
            "--cached",
            "--others",
            "--exclude-standard",
            "--",
        ])
        .args(INPUTS)
        .output()?;
    anyhow::ensure!(
        files.status.success(),
        "git ls-files: {}",
        String::from_utf8_lossy(&files.stderr)
    );
    let mut hash = std::collections::hash_map::DefaultHasher::new();
    tree.stdout.hash(&mut hash);
    let mut names: Vec<_> = files
        .stdout
        .split(|byte| *byte == 0)
        .filter(|name| !name.is_empty())
        .collect();
    names.sort_unstable();
    for name in names {
        name.hash(&mut hash);
        let path = repo.join(std::ffi::OsStr::from_bytes(name));
        match std::fs::symlink_metadata(&path) {
            Ok(metadata) => {
                metadata.permissions().mode().hash(&mut hash);
                if metadata.file_type().is_symlink() {
                    std::fs::read_link(path)?.hash(&mut hash);
                } else {
                    std::fs::read(path)?.hash(&mut hash);
                }
            }
            Err(error) if error.kind() == std::io::ErrorKind::NotFound => {
                "deleted".hash(&mut hash);
            }
            Err(error) => return Err(error.into()),
        }
    }
    Ok(format!("{:016x}\n", hash.finish()))
}

pub fn cwd_init() {
    static INIT: OnceLock<()> = OnceLock::new();
    INIT.get_or_init(|| {
        let _guard = BUILD.lock().unwrap();
        let userland = Path::new(env!("CARGO_MANIFEST_DIR")).join("../userland");
        if !userland.join("cwd-init/init.o").is_file() {
            assert!(
                Command::new("nu")
                    .args(["--no-config-file", "cwd-init/build.nu"])
                    .current_dir(userland)
                    .status()
                    .unwrap()
                    .success()
            );
        }
    });
}

pub fn build_brush() -> std::io::Result<ExitStatus> {
    let _guard = BUILD.lock().unwrap();
    Command::new("nu")
        .args(["--no-config-file", "brush/build.nu"])
        .env("CARGO_TARGET_DIR", target_dir())
        .current_dir(Path::new(env!("CARGO_MANIFEST_DIR")).join("../userland"))
        .status()
}

pub fn build_git() -> &'static Path {
    static GIT: OnceLock<PathBuf> = OnceLock::new();
    GIT.get_or_init(|| {
        let userland = Path::new(env!("CARGO_MANIFEST_DIR")).join("../userland");
        let target = target_dir();
        cwd_init();
        assert!(
            Command::new("cargo")
                .args([
                    "build",
                    "--release",
                    "-p",
                    "git",
                    "-p",
                    "sausage-archive-tools",
                    "--manifest-path"
                ])
                .arg(userland.join("../Cargo.toml"))
                .args(["--target", "wasm32-wasip2", "--target-dir"])
                .arg(&target)
                .args(["-j", "2", "--locked"])
                .current_dir(&userland)
                .status()
                .unwrap()
                .success()
        );
        target
    })
}