use std::ffi::OsStr;
use std::path::PathBuf;

use zagan_bet::client::paths::{data_dir_from, database_path, parse_args, APP_DIR, DATABASE_FILE};

fn args(values: &[&str]) -> Result<zagan_bet::client::paths::ClientArgs, String> {
    parse_args(values.iter().map(|value| value.to_string()))
}

#[test]
fn the_data_directory_follows_the_xdg_spec() {
    let xdg = OsStr::new("/home/user/.local/share");
    let home = OsStr::new("/home/user");
    assert_eq!(
        data_dir_from(Some(xdg), Some(home), None),
        PathBuf::from("/home/user/.local/share").join(APP_DIR)
    );

    // A relative XDG_DATA_HOME is invalid and must be ignored.
    assert_eq!(
        data_dir_from(Some(OsStr::new("relative/path")), Some(home), None),
        PathBuf::from("/home/user/.local/share").join(APP_DIR)
    );

    // No XDG: HOME/.local/share.
    assert_eq!(
        data_dir_from(None, Some(home), None),
        PathBuf::from("/home/user/.local/share").join(APP_DIR)
    );

    // Windows: APPDATA wins over HOME when XDG is unset.
    assert_eq!(
        data_dir_from(None, Some(home), Some(OsStr::new("/home/user/AppData/Roaming"))),
        PathBuf::from("/home/user/AppData/Roaming").join(APP_DIR)
    );

    // No usable home at all: stay relative rather than guessing.
    assert_eq!(
        data_dir_from(Some(OsStr::new("")), Some(OsStr::new("")), Some(OsStr::new(""))),
        PathBuf::from(APP_DIR)
    );
}

#[test]
fn the_database_lives_inside_the_data_directory() {
    assert_eq!(
        database_path(&PathBuf::from("/tmp/zagan")),
        PathBuf::from("/tmp/zagan").join(DATABASE_FILE)
    );
}

#[test]
fn dash_d_sets_the_data_directory() {
    let parsed = args(&["-d", "/tmp/zagan-data"]).unwrap();
    assert_eq!(
        parsed.data_dir,
        Some(PathBuf::from("/tmp/zagan-data"))
    );
    assert!(!parsed.unsafe_mode);
    assert!(!parsed.help);

    let parsed = args(&["--data-dir", "/var/lib/zagan"]).unwrap();
    assert_eq!(parsed.data_dir, Some(PathBuf::from("/var/lib/zagan")));

    let parsed = args(&["--data-dir=/var/lib/zagan"]).unwrap();
    assert_eq!(parsed.data_dir, Some(PathBuf::from("/var/lib/zagan")));
}

#[test]
fn flags_can_be_combined() {
    let parsed = args(&["--unsafe", "-d", "/tmp/x"]).unwrap();
    assert!(parsed.unsafe_mode);
    assert_eq!(parsed.data_dir, Some(PathBuf::from("/tmp/x")));
}

#[test]
fn bad_arguments_are_rejected_with_usage() {
    let error = args(&["-d"]).unwrap_err();
    assert!(error.contains("needs a directory"), "{error}");
    assert!(error.contains("usage:"), "{error}");

    let error = args(&["--data-dir="]).unwrap_err();
    assert!(error.contains("needs a directory"), "{error}");

    let error = args(&["--nope"]).unwrap_err();
    assert!(error.contains("unknown argument: --nope"), "{error}");
}

#[test]
fn help_is_a_flag_not_an_error() {
    let parsed = args(&["-h"]).unwrap();
    assert!(parsed.help);
    let parsed = args(&["--help"]).unwrap();
    assert!(parsed.help);
}