use std::fs::{copy, create_dir_all, read_dir};
use std::io::Result;
use std::path::Path;

/// Recursively copies the contents of a directory.
pub fn recursively_copy(source: &Path, target: &Path) -> Result<()> {
    let entries = read_dir(source)?;
    for entry in entries {
        let entry = entry?;
        let entry_type = entry.file_type()?;
        let entry_name = entry.file_name();
        let entry_source = entry.path();
        let entry_target = target.join(entry_name);

        if entry_type.is_dir() {
            create_dir_all(&entry_target)?;
            recursively_copy(&entry_source, &entry_target)?;
        } else {
            copy(&entry_source, &entry_target)?;
        }
    }

    Ok(())
}

#[cfg(test)]
mod tests {
    use std::fs::create_dir_all;

    use super::*;

    use test_utilities::*;

    #[test]
    fn test_recursively_copies_directories() {
        let test_dir = setup_test_dir();
        let source_dir = test_dir.join("source");
        let target_dir = test_dir.join("target");
        let nested_dir = source_dir.join("nested");
        let hidden_dir = source_dir.join(".hidden");
        create_dir_all(&target_dir).expect("Could not create target test directory");
        create_dir_all(&nested_dir).expect("Could not create nested test directory");
        create_dir_all(&hidden_dir).expect("Could not create hidden test directory");
        create_test_file(&source_dir.join("image.png"), "A beautiful pencil");
        create_test_file(&nested_dir.join("hello.txt"), "I am here");
        create_test_file(&nested_dir.join(".hidden"), "I am not here?");
        create_test_file(&hidden_dir.join("in_plain_sight.mkv"), "Almost");
        create_test_file(&hidden_dir.join(".hidden"), "I'm double hidden");

        recursively_copy(&source_dir, &target_dir).expect("Copy failed on test directory");

        assert_file_contents(&target_dir.join("image.png"), "A beautiful pencil");
        assert_file_contents(&target_dir.join("nested/hello.txt"), "I am here");
        assert_file_contents(&target_dir.join("nested/.hidden"), "I am not here?");
        assert_file_contents(&target_dir.join(".hidden/in_plain_sight.mkv"), "Almost");
        assert_file_contents(&target_dir.join(".hidden/.hidden"), "I'm double hidden");
        cleanup_test_dir(&test_dir);
    }

    #[test]
    fn test_empty_directory() {
        let test_dir = setup_test_dir();
        let source_dir = test_dir.join("source");
        let target_dir = test_dir.join("target");
        create_dir_all(&source_dir).expect("Could not create source test directory");
        create_dir_all(&target_dir).expect("Could not create target test directory");

        recursively_copy(&source_dir, &target_dir).expect("Copy failed on empty test directory");

        assert_eq!(target_dir.read_dir().unwrap().count(), 0);
        cleanup_test_dir(&test_dir);
    }
}