Implement adding to the playback queue from lua

7 files changed, 174 insertions, 28 deletions

diff --git a/src/database/database.cpp b/src/database/database.cpp
index dad983d0..76d3a2ab 100644
--- a/src/database/database.cpp
+++ b/src/database/database.cpp
@@ -874,6 +874,12 @@ Iterator::Iterator(std::weak_ptr<Database> db, const IndexInfo& idx)
 Iterator::Iterator(std::weak_ptr<Database> db, const Continuation& c)
     : db_(db), pos_mutex_(), current_pos_(c), prev_pos_() {}
 
+Iterator::Iterator(const Iterator& other)
+    : db_(other.db_),
+      pos_mutex_(),
+      current_pos_(other.current_pos_),
+      prev_pos_(other.prev_pos_) {}
+
 auto Iterator::Next(Callback cb) -> void {
   auto db = db_.lock();
   if (!db) {
@@ -899,6 +905,31 @@ auto Iterator::Next(Callback cb) -> void {
   });
 }
 
+auto Iterator::NextSync() -> std::optional<IndexRecord> {
+  auto db = db_.lock();
+  if (!db) {
+    return {};
+  }
+  return db->worker_task_
+      ->Dispatch<std::optional<IndexRecord>>(
+          [=]() -> std::optional<IndexRecord> {
+            std::lock_guard lock{pos_mutex_};
+            if (!current_pos_) {
+              return {};
+            }
+            std::unique_ptr<Result<IndexRecord>> res{
+                db->dbGetPage<IndexRecord>(*current_pos_)};
+            prev_pos_ = current_pos_;
+            current_pos_ = res->next_page();
+            if (!res || res->values().empty() || !res->values()[0]) {
+              ESP_LOGI(kTag, "dropping empty result");
+              return {};
+            }
+            return *res->values()[0];
+          })
+      .get();
+}
+
 auto Iterator::Prev(Callback cb) -> void {
   auto db = db_.lock();
   if (!db) {
diff --git a/src/database/include/database.hpp b/src/database/include/database.hpp
index e18701eb..36f734b8 100644
--- a/src/database/include/database.hpp
+++ b/src/database/include/database.hpp
@@ -193,12 +193,18 @@ class Iterator {
  public:
   Iterator(std::weak_ptr<Database>, const IndexInfo&);
   Iterator(std::weak_ptr<Database>, const Continuation&);
+  Iterator(const Iterator &);
+
+  auto database() const { return db_; }
 
   using Callback = std::function<void(std::optional<IndexRecord>)>;
 
   auto Next(Callback) -> void;
+  auto NextSync() -> std::optional<IndexRecord>;
+
   auto Prev(Callback) -> void;
 
+
  private:
   auto InvokeNull(Callback) -> void;
 
diff --git a/src/lua/include/lua_database.hpp b/src/lua/include/lua_database.hpp
index e47ace08..b0d2acbd 100644
--- a/src/lua/include/lua_database.hpp
+++ b/src/lua/include/lua_database.hpp
@@ -8,8 +8,12 @@
 
 #include "lua.hpp"
 
+#include "database.hpp"
+
 namespace lua {
 
+auto db_check_iterator(lua_State*, int stack_pos) -> database::Iterator*;
+
 auto RegisterDatabaseModule(lua_State*) -> void;
 
 }  // namespace lua
diff --git a/src/lua/lua_database.cpp b/src/lua/lua_database.cpp
index 4a7c82a5..d41f4794 100644
--- a/src/lua/lua_database.cpp
+++ b/src/lua/lua_database.cpp
@@ -32,7 +32,7 @@ namespace lua {
 
 static constexpr char kDbIndexMetatable[] = "db_index";
 static constexpr char kDbRecordMetatable[] = "db_record";
-static constexpr char kDbIteratorMetatable[] = "db_record";
+static constexpr char kDbIteratorMetatable[] = "db_iterator";
 
 static auto indexes(lua_State* state) -> int {
   Bridge* instance = Bridge::Get(state);
@@ -94,13 +94,37 @@ static auto push_lua_record(lua_State* L, const database::IndexRecord& r)
   std::memcpy(record->text, text.data(), text.size());
 }
 
+auto db_check_iterator(lua_State* L, int stack_pos) -> database::Iterator* {
+  database::Iterator* it = *reinterpret_cast<database::Iterator**>(
+      luaL_checkudata(L, stack_pos, kDbIteratorMetatable));
+  return it;
+}
+
+static auto push_iterator(lua_State* state,
+                          std::variant<database::Iterator*,
+                                       database::Continuation,
+                                       database::IndexInfo> val) -> void {
+  Bridge* instance = Bridge::Get(state);
+  database::Iterator** data = reinterpret_cast<database::Iterator**>(
+      lua_newuserdata(state, sizeof(uintptr_t)));
+  std::visit(
+      [&](auto&& arg) {
+        using T = std::decay_t<decltype(arg)>;
+        if constexpr (std::is_same_v<T, database::Iterator*>) {
+          *data = new database::Iterator(*arg);
+        } else {
+          *data = new database::Iterator(instance->services().database(), arg);
+        }
+      },
+      val);
+  luaL_setmetatable(state, kDbIteratorMetatable);
+}
+
 static auto db_iterate(lua_State* state) -> int {
-  luaL_checktype(state, 1, LUA_TFUNCTION);
+  database::Iterator* it = db_check_iterator(state, 1);
+  luaL_checktype(state, 2, LUA_TFUNCTION);
   int callback_ref = luaL_ref(state, LUA_REGISTRYINDEX);
 
-  database::Iterator* it = *reinterpret_cast<database::Iterator**>(
-      lua_touserdata(state, lua_upvalueindex(1)));
-
   it->Next([=](std::optional<database::IndexRecord> res) {
     events::Ui().RunOnTask([=]() {
       lua_rawgeti(state, LUA_REGISTRYINDEX, callback_ref);
@@ -116,29 +140,22 @@ static auto db_iterate(lua_State* state) -> int {
   return 0;
 }
 
+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 db_iterator_gc(lua_State* state) -> int {
-  database::Iterator** it = reinterpret_cast<database::Iterator**>(
-      luaL_checkudata(state, 1, kDbIteratorMetatable));
-  if (it != NULL) {
-    delete *it;
-  }
+  database::Iterator* it = db_check_iterator(state, 1);
+  delete it;
   return 0;
 }
 
-static auto push_iterator(
-    lua_State* state,
-    std::variant<database::Continuation, database::IndexInfo> val) -> void {
-  Bridge* instance = Bridge::Get(state);
-  database::Iterator** data = reinterpret_cast<database::Iterator**>(
-      lua_newuserdata(state, sizeof(uintptr_t)));
-  std::visit(
-      [&](auto&& arg) {
-        *data = new database::Iterator(instance->services().database(), arg);
-      },
-      val);
-  luaL_setmetatable(state, kDbIteratorMetatable);
-  lua_pushcclosure(state, db_iterate, 1);
-}
+static const struct luaL_Reg kDbIteratorFuncs[] = {{"next", db_iterate},
+                                                   {"clone", db_iterator_clone},
+                                                   {"__gc", db_iterator_gc},
+                                                   {NULL, NULL}};
 
 static auto record_text(lua_State* state) -> int {
   LuaRecord* data = reinterpret_cast<LuaRecord*>(
@@ -219,9 +236,10 @@ static auto lua_database(lua_State* state) -> int {
   luaL_setfuncs(state, kDbIndexFuncs, 0);
 
   luaL_newmetatable(state, kDbIteratorMetatable);
-  lua_pushliteral(state, "__gc");
-  lua_pushcfunction(state, db_iterator_gc);
-  lua_settable(state, -3);
+  lua_pushliteral(state, "__index");
+  lua_pushvalue(state, -2);
+  lua_settable(state, -3);  // metatable.__index = metatable
+  luaL_setfuncs(state, kDbIteratorFuncs, 0);
 
   luaL_newmetatable(state, kDbRecordMetatable);
   lua_pushliteral(state, "__index");
diff --git a/src/lua/lua_queue.cpp b/src/lua/lua_queue.cpp
index 500940a2..929a7159 100644
--- a/src/lua/lua_queue.cpp
+++ b/src/lua/lua_queue.cpp
@@ -21,6 +21,7 @@
 #include "index.hpp"
 #include "property.hpp"
 #include "service_locator.hpp"
+#include "source.hpp"
 #include "ui_events.hpp"
 
 namespace lua {
@@ -28,10 +29,28 @@ namespace lua {
 [[maybe_unused]] static constexpr char kTag[] = "lua_queue";
 
 static auto queue_add(lua_State* state) -> int {
+  Bridge* instance = Bridge::Get(state);
+
+  if (lua_isinteger(state, 1)) {
+    instance->services().track_queue().AddLast(luaL_checkinteger(state, 1));
+  } else {
+    database::Iterator* it = db_check_iterator(state, 1);
+    instance->services().track_queue().IncludeLast(
+        std::make_shared<playlist::IteratorSource>(*it));
+  }
+
+  return 0;
+}
+
+static auto queue_clear(lua_State* state) -> int {
+  Bridge* instance = Bridge::Get(state);
+  instance->services().track_queue().Clear();
   return 0;
 }
 
-static const struct luaL_Reg kQueueFuncs[] = {{"add", queue_add}, {NULL, NULL}};
+static const struct luaL_Reg kQueueFuncs[] = {{"add", queue_add},
+                                              {"clear", queue_clear},
+                                              {NULL, NULL}};
 
 static auto lua_queue(lua_State* state) -> int {
   luaL_newlib(state, kQueueFuncs);
diff --git a/src/playlist/include/source.hpp b/src/playlist/include/source.hpp
index aa15e7df..ce12faf3 100644
--- a/src/playlist/include/source.hpp
+++ b/src/playlist/include/source.hpp
@@ -9,6 +9,7 @@
 #include <deque>
 #include <memory>
 #include <mutex>
+#include <stack>
 #include <variant>
 #include <vector>
 
@@ -73,6 +74,24 @@ class IResetableSource : public ISource {
   virtual auto Reset() -> void = 0;
 };
 
+class IteratorSource : public IResetableSource {
+ public:
+  IteratorSource(const database::Iterator&);
+
+  auto Current() -> std::optional<database::TrackId> override;
+  auto Advance() -> std::optional<database::TrackId> override;
+  auto Peek(std::size_t n, std::vector<database::TrackId>*)
+      -> std::size_t override;
+
+  auto Previous() -> std::optional<database::TrackId> override;
+  auto Reset() -> void override;
+
+ private:
+  const database::Iterator& start_;
+  std::optional<database::TrackId> current_;
+  std::stack<database::Iterator, std::vector<database::Iterator>> next_;
+};
+
 auto CreateSourceFromResults(
     std::weak_ptr<database::Database>,
     std::shared_ptr<database::Result<database::IndexRecord>>)
diff --git a/src/playlist/source.cpp b/src/playlist/source.cpp
index 7a062bc7..2540c3fb 100644
--- a/src/playlist/source.cpp
+++ b/src/playlist/source.cpp
@@ -22,6 +22,55 @@
 
 namespace playlist {
 
+[[maybe_unused]] static constexpr char kTag[] = "queue_src";
+
+IteratorSource::IteratorSource(const database::Iterator& it)
+    : start_(it), current_(), next_() {
+  Reset();
+  Advance();
+}
+
+auto IteratorSource::Current() -> std::optional<database::TrackId> {
+  return current_;
+}
+
+auto IteratorSource::Advance() -> std::optional<database::TrackId> {
+  ESP_LOGI(kTag, "advancing");
+  while (!next_.empty()) {
+    auto next = next_.top().NextSync();
+    if (!next) {
+      ESP_LOGI(kTag, "top was empty");
+      next_.pop();
+      continue;
+    }
+    if (next->track()) {
+      ESP_LOGI(kTag, "top held track %lu", next->track().value_or(0));
+      current_ = next->track();
+      return current_;
+    }
+    ESP_LOGI(kTag, "top held records");
+    next_.push(database::Iterator(start_.database(), next->Expand(1).value()));
+  }
+  ESP_LOGI(kTag, "exhausted");
+  return {};
+}
+
+auto IteratorSource::Peek(std::size_t n, std::vector<database::TrackId>*)
+    -> std::size_t {
+  return 0;
+}
+
+auto IteratorSource::Previous() -> std::optional<database::TrackId> {
+  return {};
+}
+
+auto IteratorSource::Reset() -> void {
+  while (!next_.empty()) {
+    next_.pop();
+  }
+  next_.push(start_);
+}
+
 auto CreateSourceFromResults(
     std::weak_ptr<database::Database> db,
     std::shared_ptr<database::Result<database::IndexRecord>> results)