1 files changed, 155 insertions, 0 deletions
diff --git a/src/lua/lua_filesystem.cpp b/src/lua/lua_filesystem.cpp
new file mode 100644
index 00000000..5c690c16
--- /dev/null
+++ b/src/lua/lua_filesystem.cpp
@@ -0,0 +1,155 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "lua_filesystem.hpp"
+#include <string>
+#include <cstring>
+#include "lauxlib.h"
+
+namespace lua {
+
+[[maybe_unused]] static constexpr char kTag[] = "lua_fs";
+
+static constexpr char kFileEntryMetatable[] = "fs_file_entry";
+static constexpr char kFileIteratorMetatable[] = "fs_iterator";
+
+// Todo: Use std::pmr::string for paths/dirs
+struct LuaFileEntry {
+  bool isHidden;
+  bool isDirectory;
+  bool isTrack;
+  size_t path_size;
+  char path[];
+};
+
+static_assert(std::is_trivially_destructible<LuaFileEntry>());
+static_assert(std::is_trivially_copy_assignable<LuaFileEntry>());
+
+static auto push_lua_file_entry(lua_State* L, const database::FileEntry& r) -> void {
+  // Create and init the userdata.
+  LuaFileEntry* file_entry = reinterpret_cast<LuaFileEntry*>(
+      lua_newuserdata(L, sizeof(LuaFileEntry) + r.filepath.size()));
+  luaL_setmetatable(L, kFileEntryMetatable);
+
+  // Init all the fields
+  *file_entry = {
+      .isHidden = r.isHidden,
+      .isDirectory = r.isDirectory,
+      .isTrack = r.isTrack,
+      .path_size = r.filepath.size(),
+  };
+
+  // Copy the string data across.
+  std::memcpy(file_entry->path, r.filepath.data(), r.filepath.size());
+}
+
+auto check_file_iterator(lua_State* L, int stack_pos) -> database::FileIterator* {
+  database::FileIterator* it = *reinterpret_cast<database::FileIterator**>(
+      luaL_checkudata(L, stack_pos, kFileIteratorMetatable));
+  return it;
+}
+
+static auto push_iterator(lua_State* state, const database::FileIterator& it)
+    -> void {
+  database::FileIterator** data = reinterpret_cast<database::FileIterator**>(
+      lua_newuserdata(state, sizeof(uintptr_t)));
+  *data = new database::FileIterator(it); // TODO...
+  luaL_setmetatable(state, kFileIteratorMetatable);
+}
+
+static auto fs_iterate_prev(lua_State* state) -> int {
+  database::FileIterator* it = check_file_iterator(state, 1);
+  it->prev();
+  std::optional<database::FileEntry> res = it->value();
+
+  if (res) {
+    push_lua_file_entry(state, *res);
+  } else {
+    lua_pushnil(state);
+  }
+
+  return 1;
+}
+
+static auto fs_iterate(lua_State* state) -> int {
+  database::FileIterator* it = check_file_iterator(state, 1);
+  it->next();
+  std::optional<database::FileEntry> res = it->value();
+
+  if (res) {
+    push_lua_file_entry(state, *res);
+  } else {
+    lua_pushnil(state);
+  }
+
+  return 1;
+}
+
+// static auto db_iterator_clone(lua_State* state) -> int {
+//   database::Iterator* it = db_check_iterator(state, 1);
+//   push_iterator(state, *it);
+//   return 1;
+// }
+
+static auto fs_iterator_gc(lua_State* state) -> int {
+  database::FileIterator* it = check_file_iterator(state, 1);
+  delete it;
+  return 0;
+}
+
+static const struct luaL_Reg kFileIteratorFuncs[] = {{"next", fs_iterate},
+                                                   {"prev", fs_iterate_prev},
+                                                  //  {"clone", db_iterator_clone},
+                                                   {"__call", fs_iterate},
+                                                   {"__gc", fs_iterator_gc},
+                                                   {NULL, NULL}};
+
+static auto file_entry_path(lua_State* state) -> int {
+  LuaFileEntry* data = reinterpret_cast<LuaFileEntry*>(
+      luaL_checkudata(state, 1, kFileEntryMetatable));
+  lua_pushlstring(state, data->path, data->path_size);
+  return 1;
+}
+
+static const struct luaL_Reg kFileEntryFuncs[] = {{"filepath", file_entry_path},
+                                                 {"__tostring", file_entry_path},
+                                                 {NULL, NULL}};
+
+static auto fs_new_iterator(lua_State* state) -> int {
+  // Takes a filepath as a string and returns a new FileIterator
+  // on that directory
+  std::string filepath = luaL_checkstring(state, -1);
+  database::FileIterator iter(filepath);
+   push_iterator(state, iter);
+  return 1;
+}
+
+static const struct luaL_Reg kDatabaseFuncs[] = {{"iterator", fs_new_iterator},
+                                                 {NULL, NULL}};
+
+static auto lua_filesystem(lua_State* state) -> int {
+  luaL_newmetatable(state, kFileIteratorMetatable);
+  lua_pushliteral(state, "__index");
+  lua_pushvalue(state, -2);
+  lua_settable(state, -3);  // metatable.__index = metatable
+  luaL_setfuncs(state, kFileIteratorFuncs, 0);
+
+  luaL_newmetatable(state, kFileEntryMetatable);
+  lua_pushliteral(state, "__index");
+  lua_pushvalue(state, -2);
+  lua_settable(state, -3);  // metatable.__index = metatable
+  luaL_setfuncs(state, kFileEntryFuncs, 0);
+
+  luaL_newlib(state, kDatabaseFuncs);
+  return 1;
+}
+
+auto RegisterFileSystemModule(lua_State* s) -> void {
+  luaL_requiref(s, "filesystem", lua_filesystem, true);
+  lua_pop(s, 1);
+}
+
+}  // namespace lua