use std::fs::File;
use std::io::prelude::*;
use std::io::{Seek, Write};
use std::iter::Iterator;
use std::path::Path;
use walkdir::{DirEntry, WalkDir};
use zip::result::ZipError;
use zip::write::FileOptions;

fn zip_dir<T>(
    it: &mut dyn Iterator<Item = DirEntry>,
    prefix: &str,
    writer: T,
) -> zip::result::ZipResult<()>
where
    T: Write + Seek,
{
    let mut zip = zip::ZipWriter::new(writer);
    let mut options = FileOptions::default()
        .compression_method(zip::CompressionMethod::Zstd)
        .unix_permissions(0o755);
    if let Ok(v) = std::env::var("COMPRESS") {
        if v == "1" {
            options = options.compression_level(Some(22));
        }
    }

    let mut buffer = Vec::new();
    for entry in it {
        let path = entry.path();
        let name = path.strip_prefix(Path::new(prefix)).unwrap();

        // Write file or directory explicitly
        // Some unzip tools unzip files with directory paths correctly, some do not!
        if path.is_file() {
            println!("adding file {path:?} as {name:?} ...");
            #[allow(deprecated)]
            zip.start_file_from_path(name, options)?;
            let mut f = File::open(path)?;

            f.read_to_end(&mut buffer)?;
            zip.write_all(&buffer)?;
            buffer.clear();
        } else if !name.as_os_str().is_empty() {
            // Only if not root! Avoids path spec / warning
            // and mapname conversion failed error on unzip
            println!("adding dir {path:?} as {name:?} ...");
            #[allow(deprecated)]
            zip.add_directory_from_path(name, options)?;
        }
    }
    zip.finish()?;
    Result::Ok(())
}

fn main() -> Result<(), ZipError> {
    let _ = std::fs::remove_dir_all("target/out");
    let walkdir = WalkDir::new("assets");
    let it = walkdir.into_iter();
    println!("cargo:rerun-if-changed=assets/");
    println!("cargo:rerun-if-changed=build.rs");
    zip_dir(
        &mut it.filter_map(|e| e.ok()),
        "assets",
        File::create(std::env::var("OUT_DIR").unwrap() + "/asset").unwrap(),
    )
}