#include "UI.hpp"

#include "Model/GlobalStates.hpp"
#include "Model/Project.hpp"
#include "UI/Localization.hpp"
#include "UI/States.hpp"

#include <imgui.h>
#include <imgui_stdlib.h>

namespace {

enum class ActionResult {
	Confirmed,
	Canceled,
	Pending,
};

/// \param list Item list that the item is in.
/// \param item A non-null pointer to the currently being edited item. It should not change until this function returns a non-\c ActionResult::Pending value.
template <class T>
ActionResult ItemEditor(ItemList<T>& list, T* item) {
	constexpr bool kHasDescription = requires(T t) { t.GetDescription(); };
	constexpr bool kHasEmail = requires(T t) { t.GetEmail(); };

	auto ls = LocaleStrings::Instance.get();
	auto& uis = UIState::GetInstance();

	static bool duplicateName = false;

	static std::string name;
	static std::string description;
	static std::string email;
	if (name.empty()) {
		name = item->GetName();
		if constexpr (kHasDescription) description = item->GetDescription();
		if constexpr (kHasEmail) email = item->GetEmail();
	}

	auto ClearStates = [&]() {
		duplicateName = false;
		name = {};
		description = {};
	};

	if (ImGui::InputText(ls->ItemNameColumn.Get(), &name)) {
		duplicateName = name != item->GetName() && list.Find(name) != nullptr;
	}
	if constexpr (kHasDescription) ImGui::InputText(ls->ItemDescriptionColumn.Get(), &description);
	if constexpr (kHasEmail) ImGui::InputText(ls->ItemEmailColumn.Get(), &email);

	if (name.empty()) {
		ImGui::ErrorMessage("%s", ls->EmptyItemNameError.Get());
	}
	if (duplicateName) {
		ImGui::ErrorMessage("%s", ls->DuplicateItemNameError.Get());
	}

	// Return Value
	auto rv = ActionResult::Pending;

	if (ImGui::Button(ls->DialogConfirm.Get(), name.empty() || duplicateName)) {
		if (item->GetName() != name) {
			item->SetName(std::move(name));
		}
		if constexpr (kHasDescription)
			if (item->GetDescription() != description) {
				item->SetDescription(std::move(description));
			}
		if constexpr (kHasEmail)
			if (item->GetEmail() != email) {
				item->SetEmail(std::move(email));
			}

		ImGui::CloseCurrentPopup();
		ClearStates();
		rv = ActionResult::Confirmed;
	}

	ImGui::SameLine();
	if (ImGui::Button(ls->DialogCancel.Get())) {
		ImGui::CloseCurrentPopup();
		ClearStates();
		rv = ActionResult::Canceled;
	}

	return rv;
}

template <class T>
void ItemListEntries(ItemList<T>& list, int& selectedIdx) {
	constexpr bool kHasDescription = requires(T t) { t.GetDescription(); };
	constexpr bool kHasEmail = requires(T t) { t.GetEmail(); };
	constexpr int kColumns = 1 /* Name column */ + kHasDescription + kHasEmail;

	auto ls = LocaleStrings::Instance.get();
	auto& uis = UIState::GetInstance();

	if (ImGui::BeginTable("", kColumns, ImGuiTableFlags_Borders)) {

		ImGui::TableSetupColumn(ls->ItemNameColumn.Get());
		if constexpr (kHasDescription) ImGui::TableSetupColumn(ls->ItemDescriptionColumn.Get());
		if constexpr (kHasEmail) ImGui::TableSetupColumn(ls->ItemEmailColumn.Get());
		ImGui::TableHeadersRow();

		size_t idx = 0;
		for (auto& entry : list) {
			if (entry.IsInvalid()) {
				continue;
			}

			ImGui::TableNextRow();

			// Field: name
			ImGui::TableNextColumn();
			if (ImGui::Selectable(entry.GetName().c_str(), selectedIdx == idx, ImGuiSelectableFlags_SpanAllColumns)) {
				selectedIdx = idx;
			}

			// Field: description
			if constexpr (kHasDescription) {
				ImGui::TableNextColumn();
				ImGui::Text("%s", entry.GetDescription().c_str());
			}

			// Field: email
			if constexpr (kHasEmail) {
				ImGui::TableNextColumn();
				ImGui::Text("%s", entry.GetEmail().c_str());
			}

			idx++;
		}
		ImGui::EndTable();
	}
}

template <class T>
void ItemListEditor(ItemList<T>& list) {
	auto ls = LocaleStrings::Instance.get();

	bool opened = true;
	static int selectedIdx = -1;
	static T* editingItem = nullptr;

	if (ImGui::Button(ls->AddItem.Get())) {
		ImGui::SetNextWindowCentered();
		ImGui::OpenPopup(ls->AddItemDialogTitle.Get());

		editingItem = &list.Insert("");
	}
	if (ImGui::BeginPopupModal(ls->AddItemDialogTitle.Get(), &opened, ImGuiWindowFlags_AlwaysAutoResize)) {
		switch (ItemEditor(list, editingItem)) {
			case ActionResult::Confirmed:
				editingItem = nullptr;
				break;
			case ActionResult::Canceled:
				list.Remove(editingItem->GetId());
				editingItem = nullptr;
				break;
			default:
				break;
		}
		ImGui::EndPopup();
	}

	ImGui::SameLine();
	if (ImGui::Button(ls->EditItem.Get(), selectedIdx == -1)) {
		ImGui::SetNextWindowCentered();
		ImGui::OpenPopup(ls->EditItemDialogTitle.Get());

		editingItem = list.Find(selectedIdx);
	}
	if (ImGui::BeginPopupModal(ls->EditItemDialogTitle.Get(), &opened, ImGuiWindowFlags_AlwaysAutoResize)) {
		if (ItemEditor(list, editingItem) != ActionResult::Pending) {
			editingItem = nullptr;
		}
		ImGui::EndPopup();
	}

	ImGui::SameLine();
	if (ImGui::Button(ls->DeleteItem.Get(), selectedIdx == -1)) {
		ImGui::SetNextWindowCentered();
		ImGui::OpenPopup(ls->DeleteItemDialogTitle.Get());

		list.Remove(selectedIdx);
	}
	if (ImGui::BeginPopupModal(ls->DeleteItemDialogTitle.Get(), &opened, ImGuiWindowFlags_AlwaysAutoResize)) {
		ImGui::Text("%s", ls->DeleteItemDialogMessage.Get());

		if (ImGui::Button(ls->DialogConfirm.Get())) {
			ImGui::CloseCurrentPopup();
		}

		ImGui::SameLine();
		if (ImGui::Button(ls->DialogCancel.Get())) {
			ImGui::CloseCurrentPopup();
		}

		ImGui::EndPopup();
	}

	ItemListEntries<T>(list, selectedIdx);
}
} // namespace

void UI::ItemsTab() {
	auto ls = LocaleStrings::Instance.get();
	auto& uis = UIState::GetInstance();

	constexpr float kAmount = 16.0f;
	int id = 0;
	if (ImGui::CollapsingHeader(ls->ProductCategoryName.Get())) {
		ImGui::PushID(id++);
		ImGui::Indent(kAmount);
		ItemListEditor(uis.CurrentProject->Products);
		ImGui::Unindent(kAmount);
		ImGui::PopID();
	}
	if (ImGui::CollapsingHeader(ls->FactoryCategoryName.Get())) {
		ImGui::PushID(id++);
		ImGui::Indent(kAmount);
		ItemListEditor(uis.CurrentProject->Factories);
		ImGui::Unindent(kAmount);
		ImGui::PopID();
	}
	if (ImGui::CollapsingHeader(ls->CustomerCategoryName.Get())) {
		ImGui::PushID(id++);
		ImGui::Indent(kAmount);
		ItemListEditor(uis.CurrentProject->Customers);
		ImGui::Unindent(kAmount);
		ImGui::PopID();
	}
}