// ABOUTME: Current user detection and avatar loading for the power menu.
// ABOUTME: Retrieves user info from the system (pwd, AccountsService, ~/.face).

use nix::unistd::{getuid, User as NixUser};
use std::path::{Path, PathBuf};

const DEFAULT_ACCOUNTSSERVICE_DIR: &str = "/var/lib/AccountsService/icons";

/// Represents the current user for the power menu.
#[derive(Debug, Clone)]
pub struct User {
    pub username: String,
    pub display_name: String,
    pub home: PathBuf,
    pub uid: u32,
}

/// Get the currently logged-in user's info from the system.
pub fn get_current_user() -> Option<User> {
    let uid = getuid();
    let nix_user = NixUser::from_uid(uid).ok()??;

    let gecos = nix_user.gecos.to_str().unwrap_or("").to_string();
    // GECOS field may contain comma-separated values; first field is the full name
    let display_name = if !gecos.is_empty() {
        let first = gecos.split(',').next().unwrap_or("");
        if first.is_empty() {
            nix_user.name.clone()
        } else {
            first.to_string()
        }
    } else {
        nix_user.name.clone()
    };

    Some(User {
        username: nix_user.name,
        display_name,
        home: nix_user.dir,
        uid: uid.as_raw(),
    })
}

/// Find the user's avatar image, checking ~/.face then AccountsService.
pub fn get_avatar_path(home: &Path, username: Option<&str>) -> Option<PathBuf> {
    get_avatar_path_with(home, username, Path::new(DEFAULT_ACCOUNTSSERVICE_DIR))
}

/// Find avatar with configurable AccountsService dir (for testing).
pub fn get_avatar_path_with(
    home: &Path,
    username: Option<&str>,
    accountsservice_dir: &Path,
) -> Option<PathBuf> {
    // ~/.face takes priority — canonicalize to resolve symlinks
    let face = home.join(".face");
    if face.exists() {
        if let Ok(canonical) = std::fs::canonicalize(&face) {
            log::debug!("Avatar: using ~/.face ({})", canonical.display());
            return Some(canonical);
        }
        // canonicalize failed (e.g. permissions) — skip rather than return unresolved symlink
        log::warn!("Avatar: ~/.face exists but canonicalize failed, skipping");
    }

    // AccountsService icon — also canonicalize for consistency
    if let Some(name) = username {
        if accountsservice_dir.exists() {
            let icon = accountsservice_dir.join(name);
            if icon.exists() {
                if let Ok(canonical) = std::fs::canonicalize(&icon) {
                    log::debug!("Avatar: using AccountsService icon ({})", canonical.display());
                    return Some(canonical);
                }
                log::warn!("Avatar: AccountsService icon exists but canonicalize failed, skipping");
            }
        }
    }

    None
}

/// Return the GResource path to the default avatar SVG.
pub fn get_default_avatar_path() -> String {
    let prefix = crate::GRESOURCE_PREFIX;
    format!("{prefix}/default-avatar.svg")
}

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

    #[test]
    fn get_current_user_returns_some() {
        let user = get_current_user();
        assert!(user.is_some());
        let user = user.unwrap();
        assert!(!user.username.is_empty());
        assert!(!user.display_name.is_empty());
        assert!(user.home.exists());
    }

    #[test]
    fn returns_face_file_if_exists() {
        let dir = tempfile::tempdir().unwrap();
        let face = dir.path().join(".face");
        fs::write(&face, "fake image").unwrap();
        let path = get_avatar_path_with(dir.path(), None, Path::new("/nonexistent"));
        let expected = fs::canonicalize(&face).unwrap();
        assert_eq!(path, Some(expected));
    }

    #[test]
    fn returns_accountsservice_icon_if_exists() {
        let dir = tempfile::tempdir().unwrap();
        let icons_dir = dir.path().join("icons");
        fs::create_dir(&icons_dir).unwrap();
        let icon = icons_dir.join("testuser");
        fs::write(&icon, "fake image").unwrap();
        let path = get_avatar_path_with(dir.path(), Some("testuser"), &icons_dir);
        let expected = fs::canonicalize(&icon).unwrap();
        assert_eq!(path, Some(expected));
    }

    #[test]
    fn face_file_takes_priority_over_accountsservice() {
        let dir = tempfile::tempdir().unwrap();
        let face = dir.path().join(".face");
        fs::write(&face, "fake image").unwrap();
        let icons_dir = dir.path().join("icons");
        fs::create_dir(&icons_dir).unwrap();
        let icon = icons_dir.join("testuser");
        fs::write(&icon, "fake image").unwrap();
        let path = get_avatar_path_with(dir.path(), Some("testuser"), &icons_dir);
        let expected = fs::canonicalize(&face).unwrap();
        assert_eq!(path, Some(expected));
    }

    #[test]
    fn returns_none_when_no_avatar() {
        let dir = tempfile::tempdir().unwrap();
        let path = get_avatar_path_with(dir.path(), None, Path::new("/nonexistent"));
        assert!(path.is_none());
    }

    #[test]
    fn default_avatar_path_is_gresource() {
        let path = get_default_avatar_path();
        assert!(path.contains("default-avatar.svg"));
        assert!(path.starts_with("/dev/moonarch/moonset"));
    }
}