use std::process::Command;
use tempfile::TempDir;

fn arc_cmd() -> Command {
    let mut cmd = Command::new(env!("CARGO_BIN_EXE_arc"));
    cmd.env("NO_COLOR", "1");
    cmd
}

fn init_repo() -> TempDir {
    let dir = TempDir::new().unwrap();
    arc_cmd()
        .arg("init")
        .current_dir(dir.path())
        .output()
        .expect("failed to init");
    dir
}

fn commit_file(dir: &TempDir, name: &str, content: &str, msg: &str) -> String {
    std::fs::write(dir.path().join(name), content).unwrap();
    let output = arc_cmd()
        .args(["commit", msg])
        .current_dir(dir.path())
        .output()
        .expect("failed to commit");
    assert!(output.status.success());
    String::from_utf8_lossy(&output.stdout)
        .trim()
        .strip_prefix("✓ committed ")
        .unwrap()
        .to_string()
}

#[test]
fn merge_diverged_branches() {
    let dir = init_repo();
    commit_file(&dir, "base.txt", "base\n", "base commit");

    arc_cmd()
        .args(["mark", "add", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    commit_file(&dir, "main-file.txt", "main\n", "main change");

    arc_cmd()
        .args(["switch", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    commit_file(&dir, "feature-file.txt", "feature\n", "feature change");

    arc_cmd()
        .args(["switch", "main"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    let output = arc_cmd()
        .args(["merge", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    assert!(output.status.success());
    let stdout = String::from_utf8_lossy(&output.stdout);
    assert!(stdout.contains("merged feature"));

    assert!(dir.path().join("base.txt").exists());
    assert!(dir.path().join("main-file.txt").exists());
    assert!(dir.path().join("feature-file.txt").exists());
}

#[test]
fn merge_creates_commit_with_two_parents() {
    let dir = init_repo();
    commit_file(&dir, "base.txt", "base\n", "base");

    arc_cmd()
        .args(["mark", "add", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    commit_file(&dir, "a.txt", "main\n", "main work");

    arc_cmd()
        .args(["switch", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    commit_file(&dir, "b.txt", "feature\n", "feature work");

    arc_cmd()
        .args(["switch", "main"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    let output = arc_cmd()
        .args(["merge", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    assert!(output.status.success());
    let stdout = String::from_utf8_lossy(&output.stdout);
    let merged_line = stdout.trim();
    assert!(merged_line.contains("merged"));

    let show_output = arc_cmd()
        .args(["show", "HEAD"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    let show_stdout = String::from_utf8_lossy(&show_output.stdout);
    assert!(show_stdout.contains("parent"));
}

#[test]
fn merge_fails_with_dirty_worktree() {
    let dir = init_repo();
    commit_file(&dir, "a.txt", "a\n", "first");

    arc_cmd()
        .args(["mark", "add", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    commit_file(&dir, "b.txt", "b\n", "main work");

    arc_cmd()
        .args(["switch", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    commit_file(&dir, "c.txt", "c\n", "feature work");

    arc_cmd()
        .args(["switch", "main"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    std::fs::write(dir.path().join("dirty.txt"), "dirty\n").unwrap();

    let output = arc_cmd()
        .args(["merge", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    assert!(!output.status.success());
    let stderr = String::from_utf8_lossy(&output.stderr);
    assert!(stderr.contains("uncommitted changes"));
}

#[test]
fn merge_same_file_no_conflict() {
    let dir = init_repo();
    std::fs::write(dir.path().join("a.txt"), "line1\nline2\nline3\n").unwrap();
    arc_cmd()
        .args(["commit", "base"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    arc_cmd()
        .args(["mark", "add", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    std::fs::write(dir.path().join("a.txt"), "line1\nline2\nline3\nmain-line\n").unwrap();
    arc_cmd()
        .args(["commit", "main edit"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    arc_cmd()
        .args(["switch", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    std::fs::write(
        dir.path().join("a.txt"),
        "feature-line\nline1\nline2\nline3\n",
    )
    .unwrap();
    arc_cmd()
        .args(["commit", "feature edit"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    arc_cmd()
        .args(["switch", "main"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    let output = arc_cmd()
        .args(["merge", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    assert!(output.status.success());
}

#[test]
fn merge_conflict_reports_error() {
    let dir = init_repo();
    commit_file(&dir, "a.txt", "original\n", "base");

    arc_cmd()
        .args(["mark", "add", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    std::fs::write(dir.path().join("a.txt"), "main version\n").unwrap();
    arc_cmd()
        .args(["commit", "main change"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    arc_cmd()
        .args(["switch", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    std::fs::write(dir.path().join("a.txt"), "feature version\n").unwrap();
    arc_cmd()
        .args(["commit", "feature change"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    arc_cmd()
        .args(["switch", "main"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    let output = arc_cmd()
        .args(["merge", "feature"])
        .current_dir(dir.path())
        .output()
        .expect("failed");

    assert!(!output.status.success());
    let stderr = String::from_utf8_lossy(&output.stderr);
    assert!(stderr.contains("conflict"));
}