use log::debug;

use crate::{
    basic_types::{ModdedInstance, RootConfig},
    utils::walk_files_recursive,
};
use std::io::Write;
use std::{fs, io, os::unix, path::Path};

pub fn link_instance_to_target(
    root_config: &RootConfig,
    instance: &ModdedInstance,
    target: impl AsRef<Path>,
) -> Result<(), io::Error> {
    debug!("Linking instance to {}", target.as_ref().to_string_lossy());
    for installed_mod in &instance.mods {
        let mod_config = root_config.get_mod_by_id(&installed_mod.mod_id()).unwrap();
        let mod_source_root = root_config.get_mod_location(&mod_config);

        for (src, dst) in installed_mod.files() {
            let link_target = mod_source_root.join(src);
            let link_name = target.as_ref().join(dst);
            link_file(&link_target, &link_name)?;
        }
    }

    Ok(())
}

pub fn link_game_to_target(
    game_dir: impl AsRef<Path>,
    target: impl AsRef<Path>,
) -> Result<(), io::Error> {
    debug!("Linking install to {}", target.as_ref().to_string_lossy());
    walk_files_recursive(&game_dir)?.try_for_each(|file| {
        let link_target = file.path();
        let link_name = target
            .as_ref()
            .join(file.path().strip_prefix(&game_dir).unwrap());
        link_file(&link_target, &link_name)
    })
}

fn link_file(target: &Path, link_name: &Path) -> Result<(), io::Error> {
    if let Some(parent) = link_name.parent() {
        fs::create_dir_all(parent)?;
    }

    create_symlink_for_file(target, link_name)?;
    Ok(())
}

pub fn create_plugins_txt(
    instance: &ModdedInstance,
    target: impl AsRef<Path>,
) -> Result<(), io::Error> {
    debug!("Generating plugins.txt");
    let mut file = fs::File::create(target.as_ref().join("plugins.txt"))?;

    writeln!(file, "# Auto generated. DO NOT EDIT MANUALLY!")?;

    for plugin in instance.load_order() {
        writeln!(file, "*{}", plugin)?;
    }

    Ok(())
}

fn create_symlink_for_file(target: &Path, link_name: &Path) -> io::Result<()> {
    let absolute_path = fs::canonicalize(target)?;

    #[cfg(unix)]
    {
        unix::fs::symlink(absolute_path, link_name)
    }

    #[cfg(windows)]
    {
        std::os::windows::fs::symlink_file(target, link_name)
    }
}