use assert_cmd::cargo::CommandCargoExt as _;
use std::process::{Command, Stdio};

const NULL: &str = "/dev/null";
const TRICKY: &str = "testdata/tricky";
const A: &str = "testdata/a";
const B: &str = "testdata/b";
const ANCESTOR: &str = "testdata/ancestor";
const EXPECTED2: &str = "testdata/expected2";
const EXPECTED3: &str = "testdata/expected3";

fn merge_then_diff(args: &[&str], expected: &str) -> Result<(), Box<dyn std::error::Error>> {
    let mut merge = Command::cargo_bin("zsh_history")?
        .args(args)
        .stdout(Stdio::piped())
        .spawn()?;

    let binary_stdout = merge.stdout.take().expect("Failed to capture stdout");

    let mut diff = Command::new("diff")
        .args(&["-u", expected, "-"])
        .stdin(Stdio::from(binary_stdout))
        .stdout(Stdio::inherit())
        .stderr(Stdio::inherit())
        .spawn()?;

    let binary_status = merge.wait()?;
    if !binary_status.success() {
        return Err(format!("Merge failed with status {:?}", binary_status).into());
    }

    let diff_status = diff.wait()?;
    if !diff_status.success() {
        return Err(format!(
            "Merging {} produced unexpected result (see diff above).",
            args.join(" ")
        )
        .into());
    }

    Ok(())
}

#[test]
fn test_pass_through() -> Result<(), Box<dyn std::error::Error>> {
    for file in [NULL, TRICKY] {
        merge_then_diff(&["merge", file, NULL], file)?;
        merge_then_diff(&["merge", NULL, file], file)?;
        merge_then_diff(&["merge", file, file], file)?;
    }
    Ok(())
}

#[test]
fn test_merge() -> Result<(), Box<dyn std::error::Error>> {
    merge_then_diff(&["merge", A, B], EXPECTED2)
}

#[test]
fn test_merge_with_ancestor() -> Result<(), Box<dyn std::error::Error>> {
    merge_then_diff(&["merge", A, B, ANCESTOR], EXPECTED3)
}