use std::path::{Path, PathBuf};
use std::process;

fn get_home() -> PathBuf {
    dirs::home_dir()
        .unwrap_or(PathBuf::from("/"))
}

#[cfg(target_os = "macos")]
fn get_home_search() -> PathBuf {
    let mut path = get_home();
    path.push("/Library/Frameworks/AtomicRuntime.framework");
    path
}

#[cfg(target_os = "linux")]
fn get_home_search() -> PathBuf {
    let mut path = get_home();
    path.push("/.local/share/atomic-runtime");
    path
}

#[cfg(target_os = "windows")]
fn get_home_search() -> PathBuf {
    let mut path = get_home();
    path.push("\\AppData\\Local\\Atomic Runtime");
    path
}

#[cfg(target_os = "macos")]
fn get_search_paths() -> [PathBuf; 5] {
    [
        PathBuf::from("/Library/Frameworks/AtomicRuntime.framework"),
        PathBuf::from("/System/Library/Frameworks/AtomicRuntime.framework"),
        PathBuf::from("/usr/local/lib/atomic-runtime"),
        PathBuf::from("/opt/atomic-runtime"),
        get_home_search()
    ]
}

#[cfg(target_os = "linux")]
fn get_search_paths() -> [PathBuf; 8] {
    [
        PathBuf::from("/usr/local/lib/atomic-runtime"),
        PathBuf::from("/usr/local/lib64/atomic-runtime"),
        PathBuf::from("/usr/lib/atomic-runtime"),
        PathBuf::from("/usr/lib64/atomic-runtime"),
        PathBuf::from("/lib/atomic-runtime"),
        PathBuf::from("/lib64/atomic-runtime"),
        PathBuf::from("/opt/atomic-runtime"),
        get_home_search()
    ]
}

#[cfg(target_os = "windows")]
fn get_search_paths() -> [PathBuf; 29] {
    [
        PathBuf::from("C:\\Program Files\\Common Files\\Equestria.dev\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files\\Common Files\\Equestria.dev\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files (x86)\\Common Files\\Equestria.dev\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files (x86)\\Common Files\\Equestria.dev\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files (Arm)\\Common Files\\Equestria.dev\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files (Arm)\\Common Files\\Equestria.dev\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files\\Common Files\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files\\Common Files\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files (x86)\\Common Files\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files (x86)\\Common Files\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files (Arm)\\Common Files\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files (Arm)\\Common Files\\Atomic Runtime"),
        PathBuf::from("C:\\Windows\\AtomicRuntime"),
        PathBuf::from("C:\\Windows\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files\\Equestria.dev\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files\\Equestria.dev\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files (x86)\\Equestria.dev\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files (x86)\\Equestria.dev\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files (Arm)\\Equestria.dev\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files (Arm)\\Equestria.dev\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files (x86)\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files (x86)\\Atomic Runtime"),
        PathBuf::from("C:\\Program Files (Arm)\\AtomicRuntime"),
        PathBuf::from("C:\\Program Files (Arm)\\Atomic Runtime"),
        PathBuf::from("C:\\ProgramData\\AtomicRuntime"),
        PathBuf::from("C:\\ProgramData\\Atomic Runtime"),
        get_home_search()
    ]
}

fn show_system_info() {
    println!("atomic-launcher: Starting atomic-launcher on {} ({})", std::env::consts::OS, std::env::consts::ARCH);
}

// TODO: Rename these to "Atomic"

#[cfg(target_os = "macos")]
const BINARY_PATH: &str = "Contents/MacOS/Electron";

#[cfg(target_os = "linux")]
const BINARY_PATH: &str = "electron";

#[cfg(target_os = "windows")]
const BINARY_PATH: &str = "electron.exe";

#[cfg(target_os = "macos")]
const APP_DATA_PATH: &str = "../Resources/app";

#[cfg(any(target_os = "linux", target_os = "windows"))]
const APP_DATA_PATH: &str = "./resources/app";

fn main() {
    show_system_info();
    println!("atomic-launcher: Compiled against rustc {}", rustc_version_runtime::version());

    let exec_path = std::env::current_exe().ok();
    let work_dir = exec_path.as_ref().and_then(|p| p.parent())
        .unwrap_or(Path::new("/"));

    println!("atomic-launcher: Current directory: {}", work_dir
        .to_str()
        .unwrap_or("/"));

    let mut found_app = false;
    let mut app_path = PathBuf::from(work_dir);
    app_path.push(APP_DATA_PATH);

    if app_path.exists() {
        found_app = true;
    } else {
        println!("atomic-launcher: Warning: Could not find Electron-compatible app. Looked in {}. The default atomic-runtime application will be opened instead.", app_path
            .to_str()
            .unwrap_or("/"));
    }

    let runtime_search_paths = get_search_paths();

    println!("atomic-launcher: Looking for atomic-runtime in: {}", runtime_search_paths
        .iter()
        .map(|i| i
            .to_str()
            .unwrap_or("/"))
        .collect::<Vec<&str>>()
        .join(", ")
        .as_str());
    let mut valid_path: Option<PathBuf> = None;

    for path in runtime_search_paths {
        let path_str = path.to_str().unwrap_or("/");
        if path.as_path().exists() && Path::new(&format!("{}/{}", path_str, BINARY_PATH)).exists() {
            valid_path = Some(path);
            break;
        }
    }

    if let Some(path) = valid_path {
        println!("atomic-launcher: Found atomic-runtime at {}", Path::new(&format!("{}/{}", path
            .to_str()
            .unwrap_or(""), BINARY_PATH))
            .to_str()
            .unwrap_or(""));
        let mut cmd = process::Command::new(Path::new(&format!("{}/{}", path
            .to_str()
            .unwrap_or(""), BINARY_PATH)));
        println!("atomic-launcher: Executing: {:?}", cmd);

        if found_app {
            cmd.arg(app_path);
        }

        if let Ok(mut app) = cmd.spawn() {
            process::exit(app.wait()
                .unwrap_or_default()
                .code()
                .unwrap_or(255));
        } else {
            eprintln!("atomic-launcher: Application failed to start.");
            process::exit(3);
        }

    } else {
        eprintln!("atomic-launcher: Could not find a valid atomic-runtime path. Aborting.");
        process::exit(2);
    }
}