use crate::backup;
use crate::config::{AlbatrossConfig, WorldConfig, WorldType};
use crate::discord::send_webhook;
use crate::region::Region;
use chrono::{NaiveDateTime, Utc};
use flate2::read::GzDecoder;
use flate2::write::GzEncoder;
use flate2::Compression;
use std::convert::TryFrom;
use std::fs::{
    copy, create_dir, create_dir_all, remove_dir_all, remove_file, rename, DirEntry, File,
};
use std::path::PathBuf;
use std::time::Instant;
use tar::Archive;

/// Backup a file
///
/// # Param
/// * `file_name` - file name
/// * `world_path` - path to the world folder
/// * `backup_path` - path to the backup folder
pub fn backup_file(
    file_name: &str,
    mut world_path: PathBuf,
    mut backup_path: PathBuf,
) -> Result<u64, std::io::Error> {
    world_path.push(file_name);
    backup_path.push(file_name);

    copy(world_path, backup_path)
}

/// Backup a directory
///
/// # Param
/// * `dir_name` - directory name
/// * `world_path` - path to the world folder
/// * `backup_path` - path to the backup folder
pub fn backup_dir(
    dir_name: &str,
    world_path: &PathBuf,
    backup_path: &PathBuf,
) -> Result<u64, std::io::Error> {
    let mut src_dir = world_path.clone();
    src_dir.push(dir_name);
    let mut backup_dir = backup_path.clone();
    backup_dir.push(dir_name);
    create_dir(&backup_dir)?;

    let mut file_count = 0;
    for entry in src_dir.read_dir()? {
        let entry = entry?;
        let mut target = backup_dir.clone();
        target.push(entry.file_name());

        copy(entry.path(), target)?;
        file_count += 1;
    }

    Ok(file_count)
}

/// Backup the regions
///
/// # Param
/// * `dir_name` - name of the backup folder
/// * `save_radius` - block radius to save
/// * `world_path` - path to the world folder
/// * `backup_path` - path to the backup folder
pub fn backup_region(
    dir_name: &str,
    save_radius: u64,
    world_path: &PathBuf,
    backup_path: &PathBuf,
) -> Result<u64, std::io::Error> {
    let mut count: u64 = 0;
    let mut src_dir = world_path.clone();
    src_dir.push(dir_name);
    let mut backup_dir = backup_path.clone();
    backup_dir.push(dir_name);
    create_dir(&backup_dir)?;

    let save_radius = (save_radius as f64 / 512.0).ceil() as i64;

    for entry in src_dir.read_dir()? {
        let entry = entry?;
        let file_name = entry.file_name().to_str().unwrap().to_string();

        if let Ok(region) = Region::try_from(file_name) {
            if region.x.abs() <= save_radius && region.y.abs() <= save_radius {
                let mut target = backup_dir.clone();
                target.push(entry.file_name());

                copy(entry.path(), target)?;
                count += 1;
            }
        }
    }

    Ok(count)
}

/// Backup a world
///
/// # Param
/// * `world_path` - path to the world folder
/// * `backup_path` - path to the backup folder
/// * `world_config` - world config options
pub fn backup_world(
    world_path: PathBuf,
    mut backup_path: PathBuf,
    world_config: &WorldConfig,
) -> Result<u64, std::io::Error> {
    let region_count;
    backup_path.push(&world_config.world_name);
    create_dir(backup_path.as_path())?;

    backup_region("poi", world_config.save_radius, &world_path, &backup_path)?;
    region_count = backup_region(
        "region",
        world_config.save_radius,
        &world_path,
        &backup_path,
    )?;
    Ok(region_count)
}

/// Backup the overworld
///
/// # Param
/// * `world_path` - path to the world folder
/// * `backup_path` - path to the backup folder
/// * `world_config` - world config options
pub fn backup_overworld(
    world_path: PathBuf,
    backup_path: PathBuf,
    world_config: &WorldConfig,
) -> Result<(u64, u64), std::io::Error> {
    backup_dir("data", &world_path, &backup_path)?;
    backup_dir("stats", &world_path, &backup_path)?;

    backup_file("level.dat", world_path.clone(), backup_path.clone())?;
    backup_file("level.dat_old", world_path.clone(), backup_path.clone())?;
    backup_file("session.lock", world_path.clone(), backup_path.clone())?;
    backup_file("uid.dat", world_path.clone(), backup_path.clone())?;

    let player_count = backup_dir("playerdata", &world_path, &backup_path)?;
    let region_count = backup_world(world_path, backup_path, world_config)?;

    Ok((region_count, player_count))
}

/// Backup the nether
///
/// # Param
/// * `world_path` - path to the world folder
/// * `backup_path` - path to the backup folder
/// * `world_config` - world config options
pub fn backup_nether(
    world_path: PathBuf,
    backup_path: PathBuf,
    world_config: &WorldConfig,
) -> Result<u64, std::io::Error> {
    let mut nether_path = world_path;
    nether_path.push("DIM-1");

    backup_world(nether_path, backup_path, world_config)
}

/// Backup the end
///
/// # Param
/// * `world_path` - path to the world folder
/// * `backup_path` - path to the backup folder
/// * `world_config` - world config options
pub fn backup_end(
    world_path: PathBuf,
    backup_path: PathBuf,
    world_config: &WorldConfig,
) -> Result<u64, std::io::Error> {
    let mut end_path = world_path;
    end_path.push("DIM1");

    backup_world(end_path, backup_path, world_config)
}

/// Compress the backup after the files have been copied
///
/// # Param
/// * `tmp_dir`: tmp directory with the backed up files
/// * `output_file`: output archive
pub fn compress_backup(tmp_dir: &PathBuf, output_file: &PathBuf) -> Result<(), std::io::Error> {
    let archive = File::create(output_file)?;
    let enc = GzEncoder::new(archive, Compression::default());
    let mut tar_builder = tar::Builder::new(enc);
    tar_builder.append_dir_all(".", tmp_dir)?;
    Ok(())
}

/// Takes an existing backup and converts it to a singleplayer world
///
/// # Param
/// * config - Albatross config
/// * backup - path of the backup to convert
/// * output - output path
pub fn convert_backup_to_sp(
    config: &AlbatrossConfig,
    backup: &PathBuf,
    output: &PathBuf,
) -> Result<(), std::io::Error> {
    let backup_file = File::open(backup)?;
    let dec = GzDecoder::new(backup_file);
    let mut extract = Archive::new(dec);
    let extract_path = PathBuf::from("tmp");
    extract.unpack(&extract_path)?;

    if let Some(worlds) = &config.world_config {
        for world in worlds {
            let world_type = match world.world_type.clone() {
                Some(world_type) => world_type,
                None => WorldType::OVERWORLD,
            };
            let src = PathBuf::from(&extract_path).join(&world.world_name);
            let dest = PathBuf::from(&extract_path);
            match world_type {
                WorldType::OVERWORLD => {
                    rename(src.clone().join("poi"), dest.clone().join("poi"))?;
                    rename(src.clone().join("region"), dest.clone().join("region"))?;
                }
                WorldType::NETHER => {
                    rename(src, dest.clone().join("DIM-1"))?;
                }
                WorldType::END => {
                    rename(src, dest.clone().join("DIM1"))?;
                }
            }
        }
    }

    compress_backup(&extract_path, output)?;
    remove_dir_all(&extract_path)?;

    Ok(())
}

/// Get the time of the backup from a file name
///
/// # Param
/// * `archive_entry`: archive entry
fn get_time_from_file_name(
    archive_entry: &DirEntry,
) -> Result<Option<NaiveDateTime>, std::io::Error> {
    let file_name = archive_entry.file_name().to_str().unwrap().to_string();
    let name: Vec<&str> = file_name.split("_backup.tar.gz").collect();

    Ok(chrono::NaiveDateTime::parse_from_str(name[0], "%d-%m-%y_%H.%M.%S").ok())
}

/// Removes the old backups from the ouput directory
///
/// # Params
/// * `output_dir` - output directory containing
/// * `keep` - number of backups to keep
fn remove_old_backups(output_dir: &PathBuf, keep: u64) -> Result<usize, std::io::Error> {
    let mut backups = vec![];
    let mut num_of_removed_backups: usize = 0;

    for entry in output_dir.read_dir()? {
        let entry = entry?;

        if let Some(ext) = entry.path().extension() {
            if ext == "gz" {
                backups.push(entry);
            }
        }
    }

    if backups.len() > keep as usize {
        backups.sort_by(|a, b| {
            let a_time = get_time_from_file_name(a).unwrap().unwrap();
            let b_time = get_time_from_file_name(b).unwrap().unwrap();

            b_time.cmp(&a_time)
        });

        num_of_removed_backups = backups.len() - keep as usize;

        for _i in 0..num_of_removed_backups {
            let oldest = backups.pop().unwrap();
            remove_file(oldest.path())?;
        }
    }

    Ok(num_of_removed_backups)
}

/// Backup the configured worlds from a minecraft server
///
/// # Params
/// * `cfg` - config file
pub fn do_backup(cfg: AlbatrossConfig, output: Option<PathBuf>) -> Result<(), std::io::Error> {
    let server_base_dir = cfg.backup.minecraft_dir.clone();
    let worlds = cfg.world_config.clone().expect("No worlds configured");
    let time_str = Utc::now().format("%d-%m-%y_%H.%M.%S").to_string();
    let backup_name = format!("{}_backup.tar.gz", time_str);
    let mut output_archive = match output {
        Some(out_path) => out_path,
        None => cfg.backup.output_dir.clone(),
    };
    output_archive.push(backup_name);
    let mut tmp_dir = cfg.backup.output_dir.clone();
    tmp_dir.push("tmp");
    remove_dir_all(&tmp_dir).ok();

    create_dir_all(tmp_dir.clone()).unwrap();

    send_webhook("**Albatross is swooping in to backup your worlds!**", &cfg);
    let timer = Instant::now();
    for world in worlds {
        let mut world_dir = server_base_dir.clone();
        let world_name = world.world_name.clone();
        let world_type = match world.world_type.clone() {
            Some(world_type) => world_type,
            None => WorldType::OVERWORLD,
        };
        world_dir.push(world_name.clone());

        if world_dir.exists() && world_dir.is_dir() {
            send_webhook(
                format!("Starting backup of **{}**", world_name).as_str(),
                &cfg,
            );
            let webhook_msg = match world_type {
                WorldType::OVERWORLD => {
                    let (region_count, player_count) =
                        backup_overworld(world_dir.clone(), tmp_dir.clone(), &world)?;
                    format!(
                        "{} regions and {} player files backed up.",
                        region_count, player_count
                    )
                }
                WorldType::NETHER => {
                    let region_count = backup_nether(world_dir, tmp_dir.clone(), &world)?;
                    format!("{} regions backed up.", region_count)
                }
                WorldType::END => {
                    let region_count = backup_end(world_dir, tmp_dir.clone(), &world)?;
                    format!("{} regions backed up.", region_count)
                }
            };

            send_webhook(&webhook_msg, &cfg);
        } else {
            send_webhook(format!("Error: {} not found.", world_name).as_str(), &cfg);
            println!("World \"{}\" not found", world_name.clone());
        }
    }

    backup::compress_backup(&tmp_dir, &output_archive)?;

    remove_dir_all(&tmp_dir)?;

    let backups_removed = remove_old_backups(&cfg.backup.output_dir, cfg.backup.backups_to_keep)?;

    if backups_removed > 0 {
        let msg = format!(
            "Albatross mistook **{}** of your old backups for some french fries and ate them!! SKRAWWWW",
            backups_removed
        );
        send_webhook(msg.as_str(), &cfg);
    }

    let secs = timer.elapsed().as_secs();
    send_webhook(
        format!("**Full backup completed in {}s**! *SKREEEEEEEEEE*", secs).as_str(),
        &cfg,
    );
    Ok(())
}