use std::fs;
use std::io;
use std::path::Path;
use rayon::prelude::*;
use std::os::unix::fs::MetadataExt;

use super::get_var_path;
use crate::utils::parser;

pub fn delete(repo: &str, pkgname: &str) {
    let base_dir = Path::new("/pkg").join(repo);
    let pkg_dir = base_dir.join(pkgname);

    if pkg_dir.exists() {
        match fs::remove_dir_all(&pkg_dir) {
            Ok(()) => { println!("removed: {}", pkg_dir.display()) }
            Err(e) => { eprintln!("Can't remove {}: {}", pkg_dir.display(), e)}
        }

    } else {
        eprintln!("{} not installed in {}", pkgname, repo)
    }

    let subdirs = ["bin", "lib", "libexec", "include", "share"];
    for subdir in &subdirs {
        let dir_path = base_dir.join(subdir);
        if dir_path.exists() {
            match remove_unused_files(&dir_path) {
                Ok(()) => {}
                Err(_) => {}
            }
        }
    }
}


pub fn delete_recursive(repo: &str, pkgname: &str) {
    let base_dir = Path::new("/pkg").join(repo);
    let pkg_dir = base_dir.join(pkgname);

    if pkg_dir.exists() {
        let var_path = get_var_path();
        let pkg_md_path = var_path.join(format!("{}/{}.md", repo, pkgname));

        match parser::get_deps(&pkg_md_path) {
            Ok(deps) => {
                for dependency in deps.lines() {
                    let dependency = dependency.trim();
                    if !dependency.is_empty() {
                        let pkg_dir = Path::new("/pkg").join(repo).join(dependency);
                        if pkg_dir.exists() {
                            if !parser::get_use_status(repo, dependency) {
                                delete(repo, &dependency.to_string())
                            }
                        }
                    }
                }
            }
            Err(e) => {
                eprintln!("Failed to parse dependencies: {}", e)
            }
        }

        match fs::remove_dir_all(&pkg_dir) {
            Ok(()) => { println!("removed: {}", pkg_dir.display()) }
            Err(e) => { eprintln!("Can't remove {}: {}", pkg_dir.display(), e)}
        }

    } else {
        eprintln!("{} not installed in {}", pkgname, repo)
    }

    let subdirs = ["lib", "include", "bin"];
    for subdir in &subdirs {
        let dir_path = base_dir.join(subdir);
        if dir_path.exists() {
            match remove_unused_files(&dir_path) {
                Ok(()) => {}
                Err(_) => {}
            }
            match remove_unused_dirs_and_symlink(&dir_path) {
                Ok(()) => {}
                Err(_) => {}
            }
        }
    }
}


fn remove_unused_files(path: &Path) -> io::Result<()> {
    let metadata = fs::symlink_metadata(path)?;

    if metadata.file_type().is_file() {
        if get_nlink(path)? == 1 {
            fs::remove_file(path)?
        }
    } else if metadata.file_type().is_dir() {
        let entries: Vec<_> = fs::read_dir(path)?.collect::<io::Result<Vec<_>>>()?;
        entries.par_iter().try_for_each(|entry| {
            remove_unused_files(&entry.path())
        })?;
    } 

    Ok(())
}

fn remove_unused_dirs_and_symlink(path: &Path) -> io::Result<()> {
    let metadata = fs::symlink_metadata(path)?;

    if metadata.file_type().is_dir() {
        let entries: Vec<_> = fs::read_dir(path)?.collect::<io::Result<Vec<_>>>()?;
        entries.par_iter().try_for_each(|entry| {
            remove_unused_dirs_and_symlink(&entry.path())
        })?;

        if fs::read_dir(path)?.next().is_none() {
            fs::remove_dir(path)?
        }

    } else if metadata.file_type().is_symlink() {
        if let Err(_) = fs::metadata(path) {
            fs::remove_file(path)?
        }
    } 

    Ok(())
}


fn get_nlink(path: &Path) -> io::Result<u64> {
    Ok(fs::metadata(path)?.nlink())
}