#include <map>
#include <sstream>
#include <string>
#include <vector>

#include "animia/player.h"
#include "animia/util.h"

namespace animia {

namespace internal::parser {

enum class State {
	ExpectPlayerName,
	ExpectSection,
	ExpectWindow,
	ExpectExecutable,
	ExpectStrategy,
	ExpectType,
	ExpectWindowTitle,
};

size_t GetIndentation(const std::string& line) {
	return line.find_first_not_of('\t');
}

bool HandleIndentation(const size_t current,
                       const std::vector<Player>& players,
                       State& state) {
	// Each state has a definitive expected indentation
	const auto expected = [&state]() -> size_t {
		switch (state) {
			default:
			case State::ExpectPlayerName:
				return 0;
			case State::ExpectSection:
				return 1;
			case State::ExpectWindow:
			case State::ExpectExecutable:
			case State::ExpectStrategy:
			case State::ExpectType:
				return 2;
			case State::ExpectWindowTitle:
				return 3;
		}
	}();

	if (current > expected)
		return false;  // Disallow excessive indentation

	if (current < expected) {
		auto fix_state = [&]() {
			state = !current ? State::ExpectPlayerName : State::ExpectSection;
		};
		switch (state) {
			case State::ExpectWindow:
				if (players.back().windows.empty())
					return false;
				fix_state();
				break;
			case State::ExpectExecutable:
				if (players.back().executables.empty())
					return false;
				fix_state();
				break;
			case State::ExpectStrategy:
				if (players.back().strategies.empty())
					return false;
				fix_state();
				break;
			case State::ExpectType:
				fix_state();
				break;
			case State::ExpectWindowTitle:
				return false;
		}
	}

	return true;
}

bool HandleState(std::string& line, std::vector<Player>& players, State& state) {
	switch (state) {
		case State::ExpectPlayerName:
			players.push_back(Player());
			players.back().name = line;
			state = State::ExpectSection;
			break;

		case State::ExpectSection: {
			static const std::map<std::string, State> sections = {
				{"windows", State::ExpectWindow},
				{"executables", State::ExpectExecutable},
				{"strategies", State::ExpectStrategy},
				{"type", State::ExpectType},
			};
			util::TrimRight(line, ":");
			const auto it = sections.find(line);
			if (it == sections.end())
				return false;
			state = it->second;
			break;
		}

		case State::ExpectWindow:
			players.back().windows.push_back(line);
			break;

		case State::ExpectExecutable:
			players.back().executables.push_back(line);
			break;

		case State::ExpectStrategy: {
			static const std::map<std::string, Strategy> strategies = {
				{"window_title", Strategy::WindowTitle},
				{"open_files", Strategy::OpenFiles},
				{"ui_automation", Strategy::UiAutomation},
			};
			util::TrimRight(line, ":");
			const auto it = strategies.find(line);
			if (it == strategies.end())
				return false;
			const auto strategy = it->second;
			players.back().strategies.push_back(strategy);
			switch (strategy) {
				case Strategy::WindowTitle:
					state = State::ExpectWindowTitle;
					break;
			}
			break;
		}

		case State::ExpectType: {
			static const std::map<std::string, PlayerType> types = {
				{"default", PlayerType::Default},
				{"web_browser", PlayerType::WebBrowser},
			};
			const auto it = types.find(line);
			if (it == types.end())
				return false;
			players.back().type = it->second;
			break;
		}

		case State::ExpectWindowTitle:
			players.back().window_title_format = line;
			state = State::ExpectStrategy;
			break;
	}

	return true;
}

}  // namespace internal::parser

////////////////////////////////////////////////////////////////////////////////

bool ParsePlayersData(const std::string& data, std::vector<Player>& players) {
	if (data.empty())
		return false;

	std::istringstream stream(data);
	std::string line;
	size_t indentation = 0;
	auto state = internal::parser::State::ExpectPlayerName;

	while (std::getline(stream, line, '\n')) {
		if (line.empty())
			continue;  // Ignore empty lines

		indentation = internal::parser::GetIndentation(line);

		internal::util::TrimLeft(line, "\t");
		internal::util::TrimRight(line, "\n\r");

		if (line.empty() || line.front() == '#')
			continue;  // Ignore empty lines and comments

		if (!internal::parser::HandleIndentation(indentation, players, state))
			return false;

		if (!internal::parser::HandleState(line, players, state))
			return false;
	}

	return !players.empty();
}

bool ParsePlayersFile(const std::string& path, std::vector<Player>& players) {
	std::string data;

	if (!internal::util::ReadFile(path, data))
		return false;

	return ParsePlayersData(data, players);
}

}  // namespace animia