//! P4 exit: the real console agent builds Rust and Node projects, then inspects undo history.
use anyhow::{Context, ensure};
use sausage::world::World;
use sausage_vfs::journal::Entry;
use std::{
    fs,
    io::Write,
    path::{Path, PathBuf},
    process::{Child, Command, Stdio},
    time::{Duration, Instant},
};

fn checked(command: &mut Command) -> anyhow::Result<()> {
    ensure!(command.status()?.success(), "command failed: {command:?}");
    Ok(())
}
fn prepare(dir: &Path) -> anyhow::Result<PathBuf> {
    let source = Path::new(env!("CARGO_MANIFEST_DIR")).join("..");
    let userland = source.join("userland");
    let target = PathBuf::from(std::env::var("CARGO_TARGET_DIR")?);
    let bundle = Path::new(env!("CARGO_TARGET_TMPDIR")).join("p4-bundle");
    let revision = Command::new("git")
        .current_dir(&source)
        .args(["rev-parse", "HEAD"])
        .output()?;
    ensure!(revision.status.success(), "fixture revision");
    if fs::read(bundle.join("revision")).ok().as_deref() != Some(revision.stdout.as_slice()) {
        if !userland.join("cwd-init/init.o").exists() {
            crate::common::cwd_init();
        }
        checked(Command::new("cargo").current_dir(&userland).args([
            "build",
            "--release",
            "--locked",
            "-p",
            "git",
            "-p",
            "world-cargo",
            "-p",
            "box-cli",
            "-p",
            "undo",
            "-p",
            "sausage-coreutils",
        ]))?;
        ensure!(
            crate::common::build_brush()?.success(),
            "shell build failed"
        );
        fs::create_dir_all(bundle.join("bin"))?;
        fs::create_dir_all(bundle.join("src"))?;
        for (binary, name) in [
            ("brush", "sh"),
            ("brush", "bash"),
            ("git", "git"),
            ("cargo", "cargo"),
            ("box", "box"),
            ("undo", "undo"),
            ("cat", "cat"),
            ("mkdir", "mkdir"),
        ] {
            fs::copy(
                target.join(format!("wasm32-wasip2/release/{binary}.wasm")),
                bundle.join(format!("bin/{name}.wasm")),
            )?;
        }
        fs::write(bundle.join("revision"), revision.stdout)?;
    }
    World::open_with_userland(dir, Some(&bundle))?;
    let repo = dir.join("world/src/sausage");
    fs::create_dir_all(repo.join("extensions/p4"))?;
    fs::write(
        repo.join("extensions/p4/server.ts"),
        include_str!("../../js/p4-test-bundle.js"),
    )?;
    for args in [
        vec!["init", "-b", "main"],
        vec!["add", "."],
        vec!["commit", "--no-gpg-sign", "-m", "P4 fixture"],
    ] {
        checked(
            Command::new("git")
                .current_dir(&repo)
                .args(args)
                .env("GIT_AUTHOR_NAME", "P4 test")
                .env("GIT_AUTHOR_EMAIL", "p4@example.com")
                .env("GIT_COMMITTER_NAME", "P4 test")
                .env("GIT_COMMITTER_EMAIL", "p4@example.com"),
        )?;
    }
    Ok(bundle)
}
struct Running(Child);
impl Drop for Running {
    fn drop(&mut self) {
        let _ = self.0.kill();
        let _ = self.0.wait();
    }
}
fn round(dir: &Path, bundle: &Path, number: usize) -> anyhow::Result<()> {
    let stdout = dir.join(format!("round-{number}.stdout"));
    let stderr = dir.join(format!("round-{number}.stderr"));
    let mut child = Running(
        Command::new(env!("CARGO_BIN_EXE_sausage"))
            .arg("run")
            .arg(dir)
            .arg("--userland")
            .arg(bundle)
            .args(["--api-listen", "127.0.0.1:0"])
            .env("PI_PROXY_BASE_URL", "https://proxy.invalid")
            .env("PI_PROXY_API_KEY", "faux-token")
            .env_remove("CREDENTIALS_DIRECTORY")
            .stdin(Stdio::piped())
            .stdout(fs::File::create(&stdout)?)
            .stderr(fs::File::create(&stderr)?)
            .spawn()?,
    );
    writeln!(
        child.0.stdin.take().context("console stdin")?,
        "P4 start {number}"
    )?;
    let deadline = Instant::now() + Duration::from_secs(600);
    loop {
        if fs::read_to_string(&stdout)?.contains(&format!("P4_COMPLETE_{number}")) {
            break;
        }
        if let Some(status) = child.0.try_wait()? {
            anyhow::bail!("console exited: {status}");
        }
        ensure!(
            Instant::now() < deadline,
            "P4 round {number} exceeded its deadline"
        );
        std::thread::yield_now();
    }
    checked(Command::new("kill").args(["-TERM", &child.0.id().to_string()]))?;
    let deadline = Instant::now() + Duration::from_secs(20);
    loop {
        if let Some(status) = child.0.try_wait()? {
            ensure!(status.success(), "console shutdown: {status}");
            break;
        }
        ensure!(
            Instant::now() < deadline,
            "console shutdown exceeded its deadline"
        );
        std::thread::yield_now();
    }
    Ok(())
}
fn boxes_removed(dir: &Path, bundle: &Path) -> anyhow::Result<()> {
    let path = dir.join("world/tmp/p4-box-id");
    if !path.exists() {
        return Ok(());
    }
    let id = fs::read_to_string(path)?;
    let id = id.trim();
    ensure!(
        id.starts_with("tc-") && id.chars().all(|c| c.is_ascii_alphanumeric() || c == '-'),
        "invalid box ID"
    );
    // The agent's EXIT trap is primary cleanup. Recover its box even if the console fails.
    let output = Command::new(env!("CARGO_BIN_EXE_sausage"))
        .arg("sh")
        .arg(dir)
        .arg("--userland")
        .arg(bundle)
        .arg("-c")
        .arg("box ls")
        .env_remove("CREDENTIALS_DIRECTORY")
        .output()?;
    ensure!(
        output.status.success(),
        "box ls: {}",
        String::from_utf8_lossy(&output.stderr)
    );
    if String::from_utf8_lossy(&output.stdout).contains(id) {
        checked(
            Command::new(env!("CARGO_BIN_EXE_sausage"))
                .arg("sh")
                .arg(dir)
                .arg("--userland")
                .arg(bundle)
                .arg("-c")
                .arg(format!("box rm {id}"))
                .env_remove("CREDENTIALS_DIRECTORY"),
        )?;
        anyhow::bail!("Agent left {id} active. Test cleanup removed it");
    }
    println!("P4 box absent from service inventory: {id}");
    Ok(())
}
fn cache_hits(dir: &Path) -> anyhow::Result<u64> {
    let workspace = fs::read_dir(dir.join("host/builds"))?
        .next()
        .context("builder workspace")??
        .path();
    let output = Command::new("kache")
        .arg("stats")
        .env("KACHE_CACHE_DIR", workspace.join("kache"))
        .output()?;
    ensure!(
        output.status.success(),
        "kache: {}",
        String::from_utf8_lossy(&output.stderr)
    );
    let text = String::from_utf8(output.stdout)?;
    println!("P4 PRIVATE CACHE:\n{text}");
    let words: Vec<_> = text.split_whitespace().collect();
    words
        .windows(2)
        .find_map(|pair| {
            if pair[1] == "of" {
                pair[0].replace(',', "").parse().ok()
            } else {
                None
            }
        })
        .context("cache hit count")
}
#[test]
fn agent_builds_rust_and_node_twice() -> anyhow::Result<()> {
    let dir = tempfile::tempdir()?;
    let bundle = prepare(dir.path())?;
    let mut first_hits = 0;
    for number in 1..=2 {
        let outcome = round(dir.path(), &bundle, number);
        let cleanup = boxes_removed(dir.path(), &bundle);
        if outcome.is_err() {
            for stream in ["stdout", "stderr"] {
                eprintln!(
                    "P4 round {number} {stream}:\n{}",
                    fs::read_to_string(dir.path().join(format!("round-{number}.{stream}")))?
                );
            }
        }
        outcome?;
        cleanup?;
        let world = dir.path().join("world");
        ensure!(
            world
                .join("src/demo-cli/target/wasm32-wasip2/release/demo-cli.wasm")
                .is_file(),
            "missing world artifact"
        );
        ensure!(
            fs::read_to_string(world.join("src/demo-cli/Cargo.toml"))?.contains("serde_json"),
            "cargo add did not reach world"
        );
        ensure!(
            fs::read_to_string(world.join("src/demo-node/result.txt"))? == "P4 npm test passed\n",
            "Node result missing"
        );
        let entries: Vec<Entry> =
            serde_json::from_slice(&fs::read(world.join("tmp/p4-undo.json"))?)?;
        for (phase, path) in [
            (0, "/src/demo-cli/Cargo.toml"),
            (1, "/src/demo-cli/src/main.rs"),
        ] {
            let tag = format!("p4-{number}-{phase}");
            ensure!(
                entries.iter().any(|entry| entry.tag == tag
                    && entry.program == "bash"
                    && entry.changed_paths.iter().any(|p| p == path)),
                "undo lost {tag}: {path}"
            );
        }
        let hits = cache_hits(dir.path())?;
        if number == 1 {
            first_hits = hits;
        } else {
            ensure!(
                hits > first_hits,
                "second run missed kache: {first_hits} -> {hits}"
            );
            println!("P4 CACHE SECOND RUN: {first_hits} -> {hits} hits");
        }
    }
    Ok(())
}