dirs-lite 1.0.2

use std::env;
use std::path::PathBuf;

const CONFIG_DIR: &str = ".config";
const DATA_DIR: &str = ".local/share";
const CACHE_DIR: &str = ".cache";

/// Returns the path to the user's config directory.
///
/// The returned value depends on the operating system and is either a `Some`, containing a value from the following table, or a `None`.
///
/// |Platform | Value                                 | Example                                  |
/// | ------- | ------------------------------------- | ---------------------------------------- |
/// | Linux   | `$XDG_CONFIG_HOME` or `$HOME`/.config | /home/alice/.config                      |
/// | macOS   | `$HOME`/Library/Application Support   | /Users/Alice/Library/Application Support |
/// | Windows | `%APPDATA%`\Roaming                 | C:\Users\Alice\AppData\Roaming           |
///
/// NOTE: if the feature `favor-xdg-style` is enabled, `$HOME/.config` is favorized.
pub fn config_dir() -> Option<PathBuf> {
    if cfg!(target_os = "linux") {
        // Linux: Use $HOME/.config
        env::var_os("XDG_CONFIG_HOME")
            .filter(|s| !s.is_empty())
            .map(PathBuf::from)
            .or_else(|| {
                std::env::home_dir().map(|mut base| {
                    base.push(CONFIG_DIR);
                    base
                })
            })
    } else if cfg!(target_os = "macos") {
        // macOS: Use $HOME/Library/Application Support
        //  or $HOME/.config if favor-xdg-style is enabled
        std::env::home_dir().map(|mut home| {
            if cfg!(feature = "favor-xdg-style") {
                home.push(CONFIG_DIR);
                return home;
            }
            home.push("Library");
            home.push("Application Support");
            home
        })
    } else if cfg!(target_os = "windows") {
        // Windows: Use %APPDATA%
        env::var_os("APPDATA")
            .filter(|s| !s.is_empty())
            .map(PathBuf::from)
    } else {
        // Unsupported platform
        None
    }
}

/// Returns the path to the user's data directory.
///
/// The returned value depends on the operating system and is either a `Some`, containing a value from the following table, or a `None`.
///
/// |Platform | Value                                 | Example                                  |
/// | ------- | ------------------------------------- | ---------------------------------------- |
/// | Linux   | `$XDG_DATA_HOME` or `$HOME`/.local/share | /home/alice/.local/share              |
/// | macOS   | `$HOME`/Library/Application Support   | /Users/Alice/Library/Application Support |
/// | Windows | `%LOCALAPPDATA%`                      | C:\Users\Alice\AppData\Local             |
///
/// NOTE: if the feature `favor-xdg-style` is enabled, `$HOME/.local/share` is favorized on macOS.
pub fn data_dir() -> Option<PathBuf> {
    if cfg!(target_os = "linux") {
        // Linux: Use $XDG_DATA_HOME or $HOME/.local/share
        env::var_os("XDG_DATA_HOME")
            .filter(|s| !s.is_empty())
            .map(PathBuf::from)
            .or_else(|| {
                std::env::home_dir().map(|mut home| {
                    home.push(DATA_DIR);
                    home
                })
            })
    } else if cfg!(target_os = "macos") {
        // macOS: Use $HOME/Library/Application Support
        //  or $HOME/.local/share if favor-xdg-style is enabled
        std::env::home_dir().map(|mut home| {
            if cfg!(feature = "favor-xdg-style") {
                home.push(DATA_DIR);
                return home;
            }
            home.push("Library");
            home.push("Application Support");
            home
        })
    } else if cfg!(target_os = "windows") {
        // Windows: Use %LOCALAPPDATA%
        env::var_os("LOCALAPPDATA")
            .filter(|s| !s.is_empty())
            .map(PathBuf::from)
    } else {
        // Unsupported platform
        None
    }
}

/// Returns the path to the user's cache directory.
///
/// The returned value depends on the operating system and is either a `Some`, containing a value from the following table, or a `None`.
///
/// |Platform | Value                                 | Example                                  |
/// | ------- | ------------------------------------- | ---------------------------------------- |
/// | Linux   | `$XDG_CACHE_HOME` or `$HOME`/.cache   | /home/alice/.cache                       |
/// | macOS   | `$HOME`/Library/Caches                | /Users/Alice/Library/Caches              |
/// | Windows | `%LOCALAPPDATA%`                      | C:\Users\Alice\AppData\Local             |
///
/// NOTE: if the feature `favor-xdg-style` is enabled, `$HOME/.cache` is favorized on macOS.
pub fn cache_dir() -> Option<PathBuf> {
    if cfg!(target_os = "linux") {
        // Linux: Use $XDG_CACHE_HOME or $HOME/.cache
        env::var_os("XDG_CACHE_HOME")
            .filter(|s| !s.is_empty())
            .map(PathBuf::from)
            .or_else(|| {
                std::env::home_dir().map(|mut home| {
                    home.push(CACHE_DIR);
                    home
                })
            })
    } else if cfg!(target_os = "macos") {
        // macOS: Use $HOME/Library/Caches
        //  or $HOME/.cache if favor-xdg-style is enabled
        std::env::home_dir().map(|mut home| {
            if cfg!(feature = "favor-xdg-style") {
                home.push(CACHE_DIR);
                return home;
            }
            home.push("Library");
            home.push("Caches");
            home
        })
    } else if cfg!(target_os = "windows") {
        // Windows: Use %LOCALAPPDATA%
        env::var_os("LOCALAPPDATA")
            .filter(|s| !s.is_empty())
            .map(PathBuf::from)
    } else {
        // Unsupported platform
        None
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    unsafe fn set_var(key: &str, value: &str) {
        unsafe { env::set_var(key, value) };
    }

    unsafe fn remove_var(key: &str) {
        unsafe { env::remove_var(key) };
    }

    fn restore_var(key: &str, original: Option<String>) {
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe {
            match original {
                Some(val) => set_var(key, &val),
                None => remove_var(key),
            }
        }
    }

    #[cfg(any(target_os = "linux", target_os = "macos"))]
    fn restore_var_os(key: &str, original: Option<std::ffi::OsString>) {
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe {
            match original {
                Some(val) => env::set_var(key, val),
                None => env::remove_var(key),
            }
        }
    }

    #[test]
    fn config_dir_returns_some() {
        let result = config_dir();
        assert!(
            result.is_some(),
            "config_dir should return Some on supported platforms"
        );
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_uses_xdg_config_home_when_set() {
        let original = env::var("XDG_CONFIG_HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("XDG_CONFIG_HOME", "/custom/.config") };

        let result = config_dir();
        assert_eq!(result, Some(PathBuf::from("/custom/.config")));

        restore_var("XDG_CONFIG_HOME", original);
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_falls_back_to_home_when_xdg_unset() {
        let original_xdg = env::var("XDG_CONFIG_HOME").ok();
        let original_home = env::var("HOME").ok();

        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe {
            remove_var("XDG_CONFIG_HOME");
            set_var("HOME", "/home/testuser");
        }

        let result = config_dir();
        assert_eq!(result, Some(PathBuf::from("/home/testuser/.config")));

        restore_var("XDG_CONFIG_HOME", original_xdg);
        restore_var("HOME", original_home);
    }

    #[test]
    #[cfg(all(target_os = "macos", not(feature = "favor-xdg-style")))]
    fn macos_config_dir_uses_library_application_support() {
        let original = env::var("HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("HOME", "/Users/testuser") };

        let result = config_dir();
        assert_eq!(
            result,
            Some(PathBuf::from("/Users/testuser/Library/Application Support"))
        );

        restore_var("HOME", original);
    }

    #[test]
    #[cfg(all(target_os = "macos", feature = "favor-xdg-style"))]
    fn macos_config_dir_uses_xdg_style() {
        let original = env::var("HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("HOME", "/Users/testuser") };

        let result = config_dir();
        assert_eq!(result, Some(PathBuf::from("/Users/testuser/.config")));

        restore_var("HOME", original);
    }

    #[test]
    #[cfg(target_os = "windows")]
    fn windows_uses_appdata() {
        let original = env::var("APPDATA").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("APPDATA", "C:\\Users\\testuser\\AppData\\Roaming") };

        let result = config_dir();
        assert_eq!(
            result,
            Some(PathBuf::from("C:\\Users\\testuser\\AppData\\Roaming"))
        );

        restore_var("APPDATA", original);
    }

    #[test]
    fn config_dir_path_is_absolute() {
        let result = config_dir();
        if let Some(path) = result {
            assert!(
                path.is_absolute(),
                "config_dir should return an absolute path"
            );
        }
    }

    #[test]
    fn data_dir_returns_some() {
        let result = data_dir();
        assert!(
            result.is_some(),
            "data_dir should return Some on supported platforms"
        );
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_data_dir_uses_xdg_data_home_when_set() {
        let original = env::var("XDG_DATA_HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("XDG_DATA_HOME", "/custom/data") };

        let result = data_dir();
        assert_eq!(result, Some(PathBuf::from("/custom/data")));

        restore_var("XDG_DATA_HOME", original);
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_data_dir_falls_back_to_home_when_xdg_unset() {
        let original_xdg = env::var("XDG_DATA_HOME").ok();
        let original_home = env::var("HOME").ok();

        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe {
            remove_var("XDG_DATA_HOME");
            set_var("HOME", "/home/testuser");
        }

        let result = data_dir();
        assert_eq!(result, Some(PathBuf::from("/home/testuser/.local/share")));

        restore_var("XDG_DATA_HOME", original_xdg);
        restore_var("HOME", original_home);
    }

    #[test]
    #[cfg(all(target_os = "macos", not(feature = "favor-xdg-style")))]
    fn macos_data_dir_uses_library_application_support() {
        let original = env::var("HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("HOME", "/Users/testuser") };

        let result = data_dir();
        assert_eq!(
            result,
            Some(PathBuf::from("/Users/testuser/Library/Application Support"))
        );

        restore_var("HOME", original);
    }

    #[test]
    #[cfg(all(target_os = "macos", feature = "favor-xdg-style"))]
    fn macos_data_dir_uses_xdg_style() {
        let original = env::var("HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("HOME", "/Users/testuser") };

        let result = data_dir();
        assert_eq!(result, Some(PathBuf::from("/Users/testuser/.local/share")));

        restore_var("HOME", original);
    }

    #[test]
    #[cfg(target_os = "windows")]
    fn windows_data_dir_uses_localappdata() {
        let original = env::var("LOCALAPPDATA").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("LOCALAPPDATA", "C:\\Users\\runneradmin\\AppData\\Local") };

        let result = data_dir();
        assert_eq!(
            result,
            Some(PathBuf::from("C:\\Users\\runneradmin\\AppData\\Local"))
        );

        restore_var("LOCALAPPDATA", original);
    }

    #[test]
    fn data_dir_path_is_absolute() {
        let result = data_dir();
        if let Some(path) = result {
            assert!(
                path.is_absolute(),
                "data_dir should return an absolute path"
            );
        }
    }

    #[test]
    fn cache_dir_returns_some() {
        let result = cache_dir();
        assert!(
            result.is_some(),
            "cache_dir should return Some on supported platforms"
        );
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_cache_dir_uses_xdg_cache_home_when_set() {
        let original = env::var("XDG_CACHE_HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("XDG_CACHE_HOME", "/custom/cache") };

        let result = cache_dir();
        assert_eq!(result, Some(PathBuf::from("/custom/cache")));

        restore_var("XDG_CACHE_HOME", original);
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_cache_dir_falls_back_to_home_when_xdg_unset() {
        let original_xdg = env::var("XDG_CACHE_HOME").ok();
        let original_home = env::var("HOME").ok();

        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe {
            remove_var("XDG_CACHE_HOME");
            set_var("HOME", "/home/testuser");
        }

        let result = cache_dir();
        assert_eq!(result, Some(PathBuf::from("/home/testuser/.cache")));

        restore_var("XDG_CACHE_HOME", original_xdg);
        restore_var("HOME", original_home);
    }

    #[test]
    #[cfg(all(target_os = "macos", not(feature = "favor-xdg-style")))]
    fn macos_cache_dir_uses_library_caches() {
        let original = env::var("HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("HOME", "/Users/testuser") };

        let result = cache_dir();
        assert_eq!(
            result,
            Some(PathBuf::from("/Users/testuser/Library/Caches"))
        );

        restore_var("HOME", original);
    }

    #[test]
    #[cfg(all(target_os = "macos", feature = "favor-xdg-style"))]
    fn macos_cache_dir_uses_xdg_style() {
        let original = env::var("HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("HOME", "/Users/testuser") };

        let result = cache_dir();
        assert_eq!(result, Some(PathBuf::from("/Users/testuser/.cache")));

        restore_var("HOME", original);
    }

    #[test]
    #[cfg(target_os = "windows")]
    fn windows_cache_dir_uses_localappdata() {
        let original = env::var("LOCALAPPDATA").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { set_var("LOCALAPPDATA", "C:\\Users\\testuser\\AppData\\Local") };

        let result = cache_dir();
        assert_eq!(
            result,
            Some(PathBuf::from("C:\\Users\\testuser\\AppData\\Local"))
        );

        restore_var("LOCALAPPDATA", original);
    }

    #[test]
    fn cache_dir_path_is_absolute() {
        let result = cache_dir();
        if let Some(path) = result {
            assert!(
                path.is_absolute(),
                "cache_dir should return an absolute path"
            );
        }
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_config_dir_handles_non_utf8_xdg() {
        use std::ffi::OsStr;
        use std::os::unix::ffi::OsStrExt;

        let original = env::var_os("XDG_CONFIG_HOME");
        let non_utf8 = OsStr::from_bytes(b"/tmp/\xff\xfe");
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { env::set_var("XDG_CONFIG_HOME", non_utf8) };

        let result = config_dir();
        let expected = PathBuf::from(non_utf8);
        assert_eq!(result, Some(expected));

        restore_var_os("XDG_CONFIG_HOME", original);
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_data_dir_handles_non_utf8_xdg() {
        use std::ffi::OsStr;
        use std::os::unix::ffi::OsStrExt;

        let original = env::var_os("XDG_DATA_HOME");
        let non_utf8 = OsStr::from_bytes(b"/tmp/\xff\xfe/data");
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { env::set_var("XDG_DATA_HOME", non_utf8) };

        let result = data_dir();
        assert_eq!(result, Some(PathBuf::from(non_utf8)));

        restore_var_os("XDG_DATA_HOME", original);
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_cache_dir_handles_non_utf8_xdg() {
        use std::ffi::OsStr;
        use std::os::unix::ffi::OsStrExt;

        let original = env::var_os("XDG_CACHE_HOME");
        let non_utf8 = OsStr::from_bytes(b"/tmp/\xff\xfe/cache");
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { env::set_var("XDG_CACHE_HOME", non_utf8) };

        let result = cache_dir();
        assert_eq!(result, Some(PathBuf::from(non_utf8)));

        restore_var_os("XDG_CACHE_HOME", original);
    }

    #[test]
    #[cfg(all(target_os = "macos", not(feature = "favor-xdg-style")))]
    fn macos_config_dir_handles_non_utf8_home() {
        use std::ffi::OsStr;
        use std::os::unix::ffi::OsStrExt;

        let original = env::var_os("HOME");
        let non_utf8_home = OsStr::from_bytes(b"/Users/\xff\xfe");
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { env::set_var("HOME", non_utf8_home) };

        let result = config_dir();
        let mut expected = PathBuf::from(non_utf8_home);
        expected.push("Library");
        expected.push("Application Support");
        assert_eq!(result, Some(expected));

        restore_var_os("HOME", original);
    }

    #[test]
    #[cfg(all(target_os = "macos", not(feature = "favor-xdg-style")))]
    fn macos_data_dir_handles_non_utf8_home() {
        use std::ffi::OsStr;
        use std::os::unix::ffi::OsStrExt;

        let original = env::var_os("HOME");
        let non_utf8_home = OsStr::from_bytes(b"/Users/\xff\xfe");
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { env::set_var("HOME", non_utf8_home) };

        let result = data_dir();
        let mut expected = PathBuf::from(non_utf8_home);
        expected.push("Library");
        expected.push("Application Support");
        assert_eq!(result, Some(expected));

        restore_var_os("HOME", original);
    }

    #[test]
    #[cfg(all(target_os = "macos", not(feature = "favor-xdg-style")))]
    fn macos_cache_dir_handles_non_utf8_home() {
        use std::ffi::OsStr;
        use std::os::unix::ffi::OsStrExt;

        let original = env::var_os("HOME");
        let non_utf8_home = OsStr::from_bytes(b"/Users/\xff\xfe");
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe { env::set_var("HOME", non_utf8_home) };

        let result = cache_dir();
        let mut expected = PathBuf::from(non_utf8_home);
        expected.push("Library");
        expected.push("Caches");
        assert_eq!(result, Some(expected));

        restore_var_os("HOME", original);
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_config_dir_ignores_empty_xdg() {
        let original_xdg = env::var("XDG_CONFIG_HOME").ok();
        let original_home = env::var("HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe {
            set_var("XDG_CONFIG_HOME", "");
            set_var("HOME", "/home/testuser");
        }

        let result = config_dir();
        assert_eq!(result, Some(PathBuf::from("/home/testuser/.config")));

        restore_var("XDG_CONFIG_HOME", original_xdg);
        restore_var("HOME", original_home);
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_data_dir_ignores_empty_xdg() {
        let original_xdg = env::var("XDG_DATA_HOME").ok();
        let original_home = env::var("HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe {
            set_var("XDG_DATA_HOME", "");
            set_var("HOME", "/home/testuser");
        }

        let result = data_dir();
        assert_eq!(result, Some(PathBuf::from("/home/testuser/.local/share")));

        restore_var("XDG_DATA_HOME", original_xdg);
        restore_var("HOME", original_home);
    }

    #[test]
    #[cfg(target_os = "linux")]
    fn linux_cache_dir_ignores_empty_xdg() {
        let original_xdg = env::var("XDG_CACHE_HOME").ok();
        let original_home = env::var("HOME").ok();
        // SAFETY: Tests run single-threaded with --test-threads=1
        unsafe {
            set_var("XDG_CACHE_HOME", "");
            set_var("HOME", "/home/testuser");
        }

        let result = cache_dir();
        assert_eq!(result, Some(PathBuf::from("/home/testuser/.cache")));

        restore_var("XDG_CACHE_HOME", original_xdg);
        restore_var("HOME", original_home);
    }
}