use std::fs::OpenOptions;
use std::path::PathBuf;
use std::{ffi::OsString, io};

use musichoard::database::NullDatabase;
use musichoard::library::{ILibrary, NullLibrary};
use musichoard::{Collection, MusicHoardBuilder};
use ratatui::{backend::CrosstermBackend, Terminal};
use structopt::StructOpt;

use musichoard::{
    database::{
        json::{backend::JsonDatabaseFileBackend, JsonDatabase},
        IDatabase,
    },
    library::beets::{
        executor::{ssh::BeetsLibrarySshExecutor, BeetsLibraryProcessExecutor},
        BeetsLibrary,
    },
    NoLibrary,
};

mod tui;
use tui::ui::Ui;
use tui::{event::EventChannel, handler::EventHandler, listener::EventListener, Tui};

#[derive(StructOpt)]
struct Opt {
    #[structopt(long = "ssh", help = "Beets SSH URI")]
    beets_ssh_uri: Option<OsString>,

    #[structopt(long = "beets", help = "Beets config file path")]
    beets_config_file_path: Option<OsString>,

    #[structopt(long = "no-library", help = "Do not connect to the library")]
    no_library: bool,

    #[structopt(
        long = "database",
        help = "Database file path",
        default_value = "database.json"
    )]
    database_file_path: PathBuf,

    #[structopt(long = "no-database", help = "Do not read from/write to the database")]
    no_database: bool,
}

fn with<LIB: ILibrary, DB: IDatabase>(builder: MusicHoardBuilder<LIB, DB>) {
    let music_hoard = builder.build();

    // Initialize the terminal user interface.
    let backend = CrosstermBackend::new(io::stdout());
    let terminal = Terminal::new(backend).expect("failed to initialise terminal");

    let channel = EventChannel::new();
    let listener = EventListener::new(channel.sender());
    let handler = EventHandler::new(channel.receiver());

    let ui = Ui::new(music_hoard).expect("failed to initialise ui");

    // Run the TUI application.
    Tui::run(terminal, ui, handler, listener).expect("failed to run tui");
}

fn with_database<DB: IDatabase>(opt: Opt, builder: MusicHoardBuilder<NoLibrary, DB>) {
    if opt.no_library {
        with(builder.set_library(NullLibrary));
    } else if let Some(uri) = opt.beets_ssh_uri {
        let uri = uri.into_string().expect("invalid SSH URI");
        let beets_config_file_path = opt
            .beets_config_file_path
            .map(|s| s.into_string())
            .transpose()
            .expect("failed to extract beets config file path");
        let lib_exec = BeetsLibrarySshExecutor::new(uri)
            .expect("failed to initialise beets")
            .config(beets_config_file_path);
        with(builder.set_library(BeetsLibrary::new(lib_exec)));
    } else {
        let lib_exec = BeetsLibraryProcessExecutor::default().config(opt.beets_config_file_path);
        with(builder.set_library(BeetsLibrary::new(lib_exec)));
    }
}

fn main() {
    let opt = Opt::from_args();
    let builder = MusicHoardBuilder::default();

    if opt.no_database {
        with_database(opt, builder.set_database(NullDatabase));
    } else {
        // Create an empty database file if it does not exist.
        match OpenOptions::new()
            .write(true)
            .create_new(true)
            .open(&opt.database_file_path)
        {
            Ok(f) => {
                drop(f);
                JsonDatabase::new(JsonDatabaseFileBackend::new(&opt.database_file_path))
                    .save::<Collection>(&vec![])
                    .expect("failed to create empty database");
            }
            Err(e) => match e.kind() {
                io::ErrorKind::AlreadyExists => {}
                _ => panic!("failed to access database file"),
            },
        }

        let db_exec = JsonDatabaseFileBackend::new(&opt.database_file_path);
        with_database(opt, builder.set_database(JsonDatabase::new(db_exec)));
    };
}

#[cfg(test)]
#[macro_use]
mod testlib;

#[cfg(test)]
mod tests {
    use once_cell::sync::Lazy;

    use musichoard::*;

    pub static COLLECTION: Lazy<Vec<Artist>> = Lazy::new(|| collection!());
}