use std::{
    env, fs,
    io::{self, Write},
    path::{Path, PathBuf},
    process,
    sync::{Arc, Mutex, OnceLock},
    thread,
};

use filesorters::Config;

static CONFIG: OnceLock<Config> = OnceLock::new();

const VERSION: &str = env!("CARGO_PKG_VERSION");

fn main() {
    let config_path = get_config_path();

    let args: Vec<String> = env::args().collect();

    if args.len() > 1
        && (args.contains(&"-v".to_string()) || args.contains(&"--version".to_string()))
    {
        println!("Filesorters version {}", VERSION);
        return;
    }

    if args.len() > 1
        && (args.contains(&"-c".to_string()) || args.contains(&"--config".to_string()))
    {
        println!("Config location: {}", config_path.display());
        return;
    }

    if args.len() > 1 && (args.contains(&"-h".to_string()) || args.contains(&"--help".to_string()))
    {
        print!(
            "Options: 
-h, --help - show this help message
-v, --version - show the version
-c, --config-path - config file location
"
        );
        return;
    }

    if !config_path.exists() {
        println!("Config file does not exist, creating...");
        filesorters::Config::create(&config_path).unwrap();
    }

    match filesorters::Config::parse(config_path.clone()) {
        Ok(parsed_config) => {
            CONFIG.set(parsed_config).unwrap();
        }
        Err(err) => {
            eprintln!("Error reading config: {}", err);
            process::exit(1);
        }
    }

    if cfg!(debug_assertions) {
        println!("config:{:#?}", CONFIG.get().unwrap())
    }

    {
        let mut counter = 1;
        for alias in CONFIG.get().unwrap().sources.keys() {
            println!("{}: {}", counter, alias);
            counter += 1;
        }
    }

    if CONFIG.get().unwrap().sources.is_empty() {
        println!(
            "No sources found, please specify them in {}",
            config_path.display()
        );
        process::exit(1);
    }

    let mut actual_selection: Vec<String> = Vec::new();

    loop {
        print!("Enter: ");
        io::stdout().flush().unwrap();
        let mut selected = String::new();
        io::stdin()
            .read_line(&mut selected)
            .expect("Failed to read line");

        let parsed_selection: Vec<usize> = selected
            .split(" ")
            .filter(|y| !y.is_empty())
            .map(|y| y.replace("\n", ""))
            .map(|y| y.replace("\r", ""))
            .flat_map(|x| x.parse::<usize>())
            .collect();

        if parsed_selection.is_empty() {
            println!("Invalid selection");
            continue;
        }
        if parsed_selection.len() > CONFIG.get().unwrap().sources.keys().len() {
            println!("Too many selections made");
            continue;
        }
        if parsed_selection
            .iter()
            .any(|x| *x > CONFIG.get().unwrap().sources.keys().len())
        {
            println!("Invalid selection");
            continue;
        }

        for selection in parsed_selection {
            actual_selection.push(
                CONFIG
                    .get()
                    .unwrap()
                    .sources
                    .keys()
                    .nth(selection - 1)
                    .unwrap()
                    .to_string(),
            );
        }

        break;
    }

    println!("Selected: {}", actual_selection.join(", "));

    let recursive: bool;

    loop {
        print!("Recursive (yes/no): ");
        io::stdout().flush().unwrap();
        let mut selected = String::new();
        io::stdin()
            .read_line(&mut selected)
            .expect("Failed to read line");

        if selected.trim().starts_with('y') {
            recursive = true;
            break;
        } else if selected.trim().starts_with('n') {
            recursive = false;
            break;
        }

        println!("Invalid answer");
    }

    let mut thread_pool: Vec<thread::JoinHandle<()>> = Vec::new();

    let total_files_sorted: Arc<Mutex<usize>> = Arc::new(Mutex::new(0));

    for selection in actual_selection {
        if cfg!(debug_assertions) {
            println!("spawned a thread with selection: {}", selection);
        }

        let tfs = Arc::clone(&total_files_sorted);
        let thread = thread::spawn(move || match sort_files(selection, recursive) {
            Ok(files_sorted) => {
                let mut num = tfs.lock().unwrap();
                *num += files_sorted
            }
            Err(err) => eprintln!("Error sorting files: {}", err),
        });

        thread_pool.push(thread);
    }

    for thread in thread_pool {
        thread.join().unwrap();
    }

    if *total_files_sorted.lock().unwrap() == 0 {
        println!("No sortable files found!");
    } else {
        println!("Sorted files: {}", total_files_sorted.lock().unwrap());
    }
}

fn sort_files(selection: String, recursive: bool) -> Result<usize, Box<dyn std::error::Error>> {
    let search_path = CONFIG
        .get()
        .and_then(|config| config.sources.get(&selection))
        .cloned()
        .unwrap();

    let file_types = [
        (
            "Picture",
            filesorters::PICTURE_EXTENTIONS.to_vec(),
            CONFIG.get().unwrap().pictures_dir.clone(),
        ),
        (
            "Book",
            filesorters::BOOK_EXTENTIONS.to_vec(),
            CONFIG.get().unwrap().books_dir.clone(),
        ),
        (
            "Video",
            filesorters::VIDEO_EXTENTIONS.to_vec(),
            CONFIG.get().unwrap().video_dir.clone(),
        ),
        (
            "Music",
            filesorters::SOUND_EXTENTIONS.to_vec(),
            CONFIG.get().unwrap().music_dir.clone(),
        ),
    ];

    fn process_directory(
        path: &std::path::Path,
        file_types: &[(&str, Vec<&str>, Option<std::path::PathBuf>)],
        recursive: bool,
    ) -> Result<usize, Box<dyn std::error::Error>> {
        let mut files_sorted: usize = 0;
        for entry in fs::read_dir(path)?.flatten() {
            let metadata = entry.metadata()?;

            if metadata.is_file() {
                if let Some(extension) = entry.path().extension().and_then(|e| e.to_str()) {
                    let file_path = entry.path();

                    for (_label, valid_extensions, target_dir_option) in file_types {
                        if let Some(target_dir) = target_dir_option {
                            if cfg!(debug_assertions) {
                                println!("{} - {}", file_path.display(), &extension);
                            }
                            if valid_extensions.contains(&extension) {
                                move_file_to_directory(&file_path, target_dir);
                                files_sorted += 1;
                            }
                        }
                    }
                }
            } else if metadata.is_dir() && recursive {
                // Recurse into the directory
                files_sorted += process_directory(&entry.path(), file_types, recursive)?;
            }
        }

        Ok(files_sorted)
    }

    process_directory(&search_path, &file_types, recursive)
}

fn move_file_to_directory(path: &Path, dir: &Path) {
    if !path.exists() {
        eprintln!("Source file does not exist");
        return;
    }

    if !dir.exists() {
        match fs::create_dir_all(dir) {
            Ok(_) => {}
            Err(err) => eprintln!(
                "Error creating destination directory({}): {}",
                dir.display(),
                err
            ),
        }
        return;
    }

    let destination = dir.join(path.file_name().unwrap_or_default());

    if cfg!(debug_assertions) {
        println!(
            "{} - {} - {}",
            path.display(),
            dir.display(),
            destination.display()
        );
    }

    match fs::rename(path, &destination) {
        Ok(()) => {}
        Err(err) => eprintln!("Error moving file: {}", err),
    }
}

#[inline]
fn get_config_path() -> PathBuf {
    if cfg!(target_os = "windows") {
        let username = env::var("USERNAME").unwrap_or_else(|_| "Default".to_string());
        PathBuf::from(format!(
            "C:\\Users\\{}\\AppData\\Local\\filesorters.toml",
            username
        ))
    } else {
        let xdg_config_home = env::var("XDG_CONFIG_HOME").ok();
        let home = env::var("HOME").ok();
        let user = env::var("USER").unwrap_or_else(|_| "default".to_string());

        xdg_config_home
            .map(|x| PathBuf::from(format!("{}/filesorters.toml", x)))
            .or_else(|| home.map(|h| PathBuf::from(format!("{}/.config/filesorters.toml", h))))
            .unwrap_or_else(|| PathBuf::from(format!("/home/{}/.config/filesorters.toml", user)))
    }
}