#include "pom.hpp"

#include <pom.h>
#include <cstring>
#include <cstdlib>
#include <string>
#include <istream>
#include <iostream>

namespace pom {

Configuration::~Configuration() {
	pom_conf_free(static_cast<pom_conf *>(C));
}

Configuration::Configuration(): C(nullptr) {}

Error::~Error() { if (m_is_original) free(C); }

Error::Error(void *C_error): C(C_error), m_is_original(true) {
	const pom_error *next = pom_error_next(static_cast<const pom_error *>(C));
	if (next)
		m_next = std::unique_ptr<Error>(new Error(static_cast<const void *>(next)));
}

// const_cast here to avoid creating a separate ConstError type
Error::Error(const void *C_error): C(const_cast<void *>(C_error)), m_is_original(false) {
	const pom_error *next = pom_error_next(static_cast<const pom_error *>(C));
	if (next)
		m_next = std::unique_ptr<Error>(new Error(static_cast<const void *>(next)));
}

std::string_view Error::file() const noexcept {
	return pom_error_file(static_cast<const pom_error *>(C));
}

uint64_t Error::line() const noexcept {
	return pom_error_line(static_cast<const pom_error *>(C));
}

std::string_view Error::message() const noexcept {
	return pom_error_message(static_cast<const pom_error *>(C));
}

const char *Error::what() const noexcept {
	return m_is_original ? pom_error_to_string(static_cast<pom_error *>(C))
		: pom_error_message(static_cast<const pom_error *>(C));
}

std::string_view Error::to_string() noexcept {
	return what();
}

std::ostream &operator<<(std::ostream &o, Error &e) {
	return o << e.to_string();
}

Configuration Configuration::section(std::string_view name) const {
	if (!C) return {};
	std::string name_str(name);
	const pom_conf *C_section = pom_conf_section(
		static_cast<const pom_conf *>(C), name_str.c_str());
	pom_conf *C_section_copy = pom_conf_copy(C_section);
	return Configuration(static_cast<void *>(C_section_copy));
}

static void *allocator_calloc(void *udata, size_t n, size_t sz) {
	return static_cast<Allocator *>(udata)->calloc(n, sz);
}

static void *allocator_realloc(void *udata, void *ptr, size_t sz) {
	return static_cast<Allocator *>(udata)->realloc(ptr, sz);
}

static void allocator_free(void *udata, void *ptr) {
	return static_cast<Allocator *>(udata)->free(ptr);
}

void Settings::set_error_language(std::string_view lang) {
	size_t len = std::min(sizeof m_error_lang - 1, lang.size());
	memcpy(m_error_lang, lang.data(), len);
	m_error_lang[len] = 0;
}

void Settings::to_C(void *C) const {
	pom_settings &C_settings = *static_cast<pom_settings *>(C);
	strcpy(C_settings.error_lang, m_error_lang);
	if (m_allocator) {
		C_settings.allocator_udata = m_allocator.get();
		C_settings.calloc = allocator_calloc;
		C_settings.realloc = allocator_realloc;
		C_settings.free = allocator_free;
	}
}

static size_t readable_read(void *udata, char *buf, size_t count) {
	return static_cast<Reader *>(udata)->read(buf, count);
}

void Configuration::load(std::string_view filename, Reader &source, const Settings *settings) {
	pom_settings C_settings = {};
	if (settings) {
		settings->to_C(static_cast<void *>(&C_settings));
	}
	pom_error *error;
	std::string filename_str(filename);
	C = pom_load(&C_settings, filename_str.c_str(), readable_read, &source, &error);
	if (error) {
		throw Error(static_cast<void *>(error));
	}
}

Configuration::Configuration(std::string_view filename, Reader &source, const Settings *settings) {
	load(filename, source, settings);
}

Configuration::Configuration(std::string_view path, const Settings *settings) {
	pom_settings C_settings = {};
	if (settings) {
		settings->to_C(static_cast<void *>(&C_settings));
	}
	pom_error *error;
	std::string path_str(path);
	C = pom_load_path(&C_settings, path_str.c_str(), &error);
	if (error) {
		throw Error(static_cast<void *>(error));
	}
}

class StringViewReader: public Reader {
public:
	explicit StringViewReader(std::string_view v): string(v) {}
	virtual size_t read(char *buf, size_t count) {
		count = std::min(count, string.size());
		memcpy(buf, string.data(), count);
		return count;
	}
private:
	std::string_view string;
};

Configuration::Configuration(std::string_view filename, std::string_view string, const Settings *settings) {
	StringViewReader reader(string);
	load(filename, reader, settings);
}

class IStreamReader: public Reader {
public:
	explicit IStreamReader(std::istream &stream): ifstream(stream) {}
	virtual size_t read(char *buf, size_t count) {
		ifstream.read(buf, count);
		return ifstream.gcount();
	}
private:
	std::istream &ifstream;
};


Configuration::Configuration(std::string_view filename, std::istream &stream, const Settings *settings) {
	IStreamReader reader(stream);
	load(filename, reader, settings);
}

void Configuration::merge(const Configuration &other) {
	if (!other.C) return;
	if (!C) {
		C = pom_conf_copy(static_cast<const pom_conf *>(other.C));
		return;
	}
	pom_conf_merge(static_cast<pom_conf *>(C), static_cast<const pom_conf *>(other.C));
}

std::optional<std::string> Configuration::get(std::string_view key) const {
	if (!C) return {};
	std::string key_str(key);
	const char *value = pom_conf_get(static_cast<const pom_conf *>(C), key_str.c_str());
	if (!value)
		return {};
	else
		return value;
}

std::string Configuration::get_or_default(std::string_view key, std::string_view dflt) const {
	auto value = get(key);
	if (value.has_value())
		return value.value();
	else
		return std::string(dflt);
}

std::vector<std::string> Configuration::unread_keys() const {
	if (!C) return {};
	std::vector<std::string> unread;
	pom_unread_key_iter *iter = nullptr;
	const char *key;
	while ((key = pom_conf_next_unread_key(static_cast<const pom_conf *>(C), &iter))) {
		unread.push_back(key);
	}
	return unread;
}

std::vector<std::string> Configuration::keys() const {
	if (!C) return {};
	std::vector<std::string> keys;
	pom_key_iter *iter = nullptr;
	const char *key;
	while ((key = pom_conf_next_key(static_cast<const pom_conf *>(C), &iter))) {
		keys.push_back(key);
	}
	return keys;
}

class ItemImpl: public Item {
public:
	ItemImpl(const pom_item *C) {
		m_key = C->key;
		m_value = C->value;
		m_file = C->file;
		m_line = C->line;
	}
	virtual ~ItemImpl() {}
	virtual std::string_view key() const noexcept override { return m_key; }
	virtual std::string_view value() const noexcept override { return m_value; }
	virtual std::string_view file() const noexcept override { return m_file; }
	virtual uint64_t line() const noexcept override { return m_line; }
	std::string m_key, m_value, m_file;
	uint64_t m_line;
};

std::vector<std::shared_ptr<Item>> Configuration::items() const {
	if (!C) return {};
	std::vector<std::shared_ptr<Item>> items;
	pom_item_iter *iter = nullptr;
	const pom_item *item;
	while ((item = pom_conf_next_item(static_cast<const pom_conf *>(C), &iter))) {
		items.push_back(std::shared_ptr<Item>(new ItemImpl(item)));
	}
	return items;
}

std::optional<int64_t> Configuration::get_int(std::string_view key) const {
	if (!C) return {};
	std::string key_str(key);
	if (!pom_conf_has(static_cast<const pom_conf *>(C), key_str.c_str())) {
		return {};
	}
	int64_t value;
	pom_error *error = pom_conf_get_int(static_cast<const pom_conf *>(C), key_str.c_str(), &value);
	if (error)
		throw Error(error);
	return value;
}

int64_t Configuration::get_int_or_default(std::string_view key, int64_t dflt) const {
	return get_int(key).value_or(dflt);
}

std::optional<uint64_t> Configuration::get_uint(std::string_view key) const {
	if (!C) return {};
	std::string key_str(key);
	if (!pom_conf_has(static_cast<const pom_conf *>(C), key_str.c_str())) {
		return {};
	}
	uint64_t value;
	pom_error *error = pom_conf_get_uint(static_cast<const pom_conf *>(C), key_str.c_str(), &value);
	if (error)
		throw Error(error);
	return value;
}

uint64_t Configuration::get_uint_or_default(std::string_view key, uint64_t dflt) const {
	return get_uint(key).value_or(dflt);
}

std::optional<double> Configuration::get_float(std::string_view key) const {
	if (!C) return {};
	std::string key_str(key);
	if (!pom_conf_has(static_cast<const pom_conf *>(C), key_str.c_str())) {
		return {};
	}
	double value;
	pom_error *error = pom_conf_get_float(static_cast<const pom_conf *>(C), key_str.c_str(), &value);
	if (error)
		throw Error(error);
	return value;
}

double Configuration::get_float_or_default(std::string_view key, double dflt) const {
	return get_float(key).value_or(dflt);
}

std::optional<bool> Configuration::get_bool(std::string_view key) const {
	if (!C) return {};
	std::string key_str(key);
	if (!pom_conf_has(static_cast<const pom_conf *>(C), key_str.c_str())) {
		return {};
	}
	bool value;
	pom_error *error = pom_conf_get_bool(static_cast<const pom_conf *>(C), key_str.c_str(), &value);
	if (error)
		throw Error(error);
	return value;
}

bool Configuration::get_bool_or_default(std::string_view key, bool dflt) const {
	return get_bool(key).value_or(dflt);
}

std::optional<std::vector<std::string>> Configuration::get_list(std::string_view key) const {
	if (!C) return {};
	std::string key_str(key);
	char **list = pom_conf_get_list(static_cast<const pom_conf *>(C), key_str.c_str());
	std::vector<std::string> vec;
	for (size_t i = 0; list[i]; i++)
		vec.emplace_back(list[i]);
	free(list);
	return vec;
}

std::vector<std::string> Configuration::get_list_or_default(std::string_view key, const std::vector<std::string> &dflt) const {
	auto list = get_list(key);
	if (list.has_value())
		return list.value();
	else
		return dflt;
}

Configuration &Configuration::operator=(const Configuration &other) {
	pom_conf_free(static_cast<pom_conf *>(C));
	C = static_cast<void *>(pom_conf_copy(static_cast<const pom_conf *>(other.C)));
	return *this;
}

std::ostream &operator<<(std::ostream &o, const Configuration &conf) {
	for (auto item: conf.items())
		o << item->key() << ": " << item->value() << "\n";
	return o;
}

std::optional<Location> Configuration::location(std::string_view key) const {
	if (!C) return {};
	const char *file;
	uint64_t line;
	std::string key_str(key);
	if (pom_conf_location(static_cast<const pom_conf *>(C), key_str.c_str(), &file, &line))
		return Location(file, line);
	else
		return {};
}

std::ostream &operator<<(std::ostream &o, const Location &location) {
	return o << location.file() << ":" << location.line();
}

} // namespace pom