import std.stdio;
import std.file;
import std.path;
import std.algorithm;

void check(string msg = "")
{
    if (msg != "")
    {
        throw new Exception(msg);
    }
}

void main()
{
    // Create a new sub-directory in the current working
    // directory.
    mkdir("subdir", 0755);

    // When creating temporary directories, it's good
    // practice to use scope(exit) for their removal.
    // std.file.rmdirRecurse will delete a whole directory tree
    // (similarly to `rm -rf`).
    scope(exit) rmdirRecurse("subdir");

    // Helper function to create a new empty file.
    void createEmptyFile(string name)
    {
        std.file.write(name, "");
    }

    createEmptyFile("subdir/file1");

    // We can create a hierarchy of directories, including
    // parents with mkdirRecurse. This is similar to the
    // command-line `mkdir -p`.
    mkdirRecurse("subdir/parent/child", 0755);

    createEmptyFile("subdir/parent/file2");
    createEmptyFile("subdir/parent/file3");
    createEmptyFile("subdir/parent/child/file4");

    // dirEntries lists directory contents, returning an
    // InputRange of DirEntry objects.
    writeln("Listing subdir/parent");
    foreach (entry; dirEntries("subdir/parent", SpanMode.shallow))
    {
        writeln(" ", entry.name, " ", entry.isDir);
    }

    // chdir lets us change the current working directory,
    // similarly to `cd`.
    chdir("subdir/parent/child");

    // Now we'll see the contents of `subdir/parent/child`
    // when listing the *current* directory.
    writeln("Listing subdir/parent/child");
    foreach (entry; dirEntries(".", SpanMode.shallow))
    {
        writeln(" ", entry.name, " ", entry.isDir);
    }

    // cd back to where we started.
    chdir("../../..");

    // We can also visit a directory *recursively*,
    // including all its sub-directories. walkDir accepts
    // a callback function to handle every file or
    // directory visited.
    writeln("Visiting subdir");
    walkDir("subdir", &visit);
}

// visit is called for every file or directory found
// recursively by walkDir.
void visit(string path)
{
    writeln(" ", path, " ", isDir(path));
}