progress_taskbar.h

/**
 * Part of WinLamb - Win32 API Lambda Library
 * https://github.com/rodrigocfd/winlamb
 * Copyright 2017-present Rodrigo Cesar de Freitas Dias
 * This library is released under the MIT License
 */

#pragma once
#include <stdexcept>
#include "com.h"
#include "wnd.h"
#include <ShObjIdl.h>

namespace wl {

// Allows to show a progress bar in the taskbar button of the window, in green, yellow or red.
class progress_taskbar final {
private:
	HWND                    _hWnd = nullptr;
	com::lib                _comLib{com::lib::init::LATER};
	com::ptr<ITaskbarList3> _bar;

public:
	progress_taskbar() = default;
	progress_taskbar(progress_taskbar&&) = default;
	progress_taskbar& operator=(progress_taskbar&&) = default; // movable only

	progress_taskbar& init(HWND hOwner) {
		if (this->_bar) {
			throw std::logic_error("Trying to init a progress taskbar twice.");
		} else {
			this->_hWnd = hOwner;
			this->_comLib.initialize();
			this->_bar.co_create_instance(CLSID_TaskbarList);
		}
		return *this;
	}

	progress_taskbar& init(const wnd* owner) {
		return this->init(owner->hwnd());
	}

	// Value is 0-100.
	progress_taskbar& set_pos(size_t percent, size_t total) noexcept {
		this->_bar->SetProgressValue(this->_hWnd, static_cast<ULONGLONG>(percent),
			static_cast<ULONGLONG>(total));
		return *this;
	}

	// Value is 0-100.
	progress_taskbar& set_pos(double percent) noexcept {
		return this->set_pos(static_cast<size_t>(percent + 0.5), 100);
	}

	progress_taskbar& set_waiting(bool isWaiting) noexcept {
		return this->_set_state(isWaiting ? TBPF_INDETERMINATE : TBPF_NORMAL);
	}

	progress_taskbar& set_pause(bool isPaused) noexcept {
		return this->_set_state(isPaused ? TBPF_PAUSED : TBPF_NORMAL);
	}

	progress_taskbar& set_error(bool hasError) noexcept {
		return this->_set_state(hasError ? TBPF_ERROR : TBPF_NORMAL);
	}

	// Removes the status from the taskbar button.
	progress_taskbar& clear() noexcept {
		return this->_set_state(TBPF_NOPROGRESS);
	}

private:
	progress_taskbar& _set_state(TBPFLAG state) noexcept {
		// Apparently this doesn't work within WM_CREATE processing.
		this->_bar->SetProgressState(this->_hWnd, state);
		return *this;
	}
};

}//namespace wl