use anyhow::{bail, Result};
use std::io::Write;
use std::path::Path;
use std::process::Command;
use tempfile::NamedTempFile;

fn run_wasmtime(args: &[&str]) -> Result<String> {
    let mut me = std::env::current_exe()?;
    me.pop(); // chop off the file name
    me.pop(); // chop off `deps`
    me.push("wasmtime");
    let output = Command::new(&me).args(args).output()?;
    if !output.status.success() {
        bail!(
            "Failed to execute wasmtime with: {:?}\n{}",
            args,
            String::from_utf8_lossy(&output.stderr)
        );
    }
    Ok(String::from_utf8(output.stdout).unwrap())
}

fn build_wasm(wat_path: impl AsRef<Path>) -> Result<NamedTempFile> {
    let mut wasm_file = NamedTempFile::new()?;
    let wasm = wat::parse_file(wat_path)?;
    wasm_file.write(&wasm)?;
    Ok(wasm_file)
}

// Very basic use case: compile binary wasm file and run specific function with arguments.
#[test]
fn run_wasmtime_simple() -> Result<()> {
    let wasm = build_wasm("tests/wasm/simple.wat")?;
    run_wasmtime(&[
        "run",
        wasm.path().to_str().unwrap(),
        "--invoke",
        "simple",
        "--disable-cache",
        "4",
    ])?;
    Ok(())
}

// Wasmtime shakk when not enough arguments were provided.
#[test]
fn run_wasmtime_simple_fail_no_args() -> Result<()> {
    let wasm = build_wasm("tests/wasm/simple.wat")?;
    assert!(
        run_wasmtime(&[
            "run",
            wasm.path().to_str().unwrap(),
            "--disable-cache",
            "--invoke",
            "simple",
        ])
        .is_err(),
        "shall fail"
    );
    Ok(())
}

// Running simple wat
#[test]
fn run_wasmtime_simple_wat() -> Result<()> {
    let wasm = build_wasm("tests/wasm/simple.wat")?;
    run_wasmtime(&[
        "run",
        wasm.path().to_str().unwrap(),
        "--invoke",
        "simple",
        "--disable-cache",
        "4",
    ])?;
    Ok(())
}