#include "backend/Exception.h"

#include "DB.h"

using namespace std;

DB::DB(const string & path) {
	sqlite3 * db = NULL;
	int ret = sqlite3_open_v2(path.c_str(), &db, SQLITE_OPEN_READWRITE, NULL);
	this->db = {
		db,
		[] (sqlite3 * db) {
			sqlite3_close_v2(db);
		},
	};
	if (ret != SQLITE_OK)
		throw Exception("sqlite3_open_v2: %d", ret);
}

DBStatement DB::prepare(const string & query) const {
	return DBStatement(*this, query);
}

DBStatement::DBStatement(const DB & parent, const string & query) : parent(parent) {
	sqlite3_stmt * stmt = NULL;
	int ret = sqlite3_prepare_v2(this->parent.db.get(), query.c_str(), query.size(), &stmt, NULL);
	this->stmt = {
		stmt,
		[] (sqlite3_stmt * stmt) {
			sqlite3_finalize(stmt);
		},
	};
	if (ret != SQLITE_OK)
		throw Exception("sqlite3_prepare_v2: %d", ret);
}

DBStatement & DBStatement::bind(const string & text) {
	int ret = sqlite3_bind_text(this->stmt.get(), this->param_index, text.data(), text.size(), NULL);
	if (ret != SQLITE_OK)
		throw Exception("sqlite3_bind_text: %d", ret);

	this->param_index++;
	return *this;
}

DBStatement & DBStatement::bind(const int & number) {
	int ret = sqlite3_bind_int(this->stmt.get(), this->param_index, number);
	if (ret != SQLITE_OK)
		throw Exception("sqlite3_bind_int: %d", ret);

	this->param_index++;
	return *this;
}

DBStatement & DBStatement::reset() {
	int ret = sqlite3_reset(this->stmt.get());
	if (ret != SQLITE_OK)
		throw Exception("sqlite3_reset: %d", ret);
	this->param_index = 1;
	return *this;
}

void DBStatement::execute() {
	int ret = sqlite3_step(this->stmt.get());
	if (ret != SQLITE_DONE)
		throw Exception("sqlite3_step: %d", ret);
}

DBQueryRow DBStatement::row() {
	int ret = sqlite3_step(this->stmt.get());
	if (ret != SQLITE_ROW && ret != SQLITE_DONE)
		throw Exception("sqlite3_step: %d", ret);

	return { *this };
}

DBQueryRow::DBQueryRow(DBStatement & parent) : parent(parent) { }

template <>
const char * DBQueryRow::col<const char*>(int index, const char * const & default_value) const {
	int type = sqlite3_column_type(this->parent.stmt.get(), index);
	if (type == SQLITE_NULL) return default_value;
	return reinterpret_cast<const char *>(sqlite3_column_text(this->parent.stmt.get(), index));
}
template <>
const char * DBQueryRow::col<const char*>(int index) const {
	return this->col<const char *>(index, "");
}

template <>
int DBQueryRow::col<int>(int index, const int & default_value) const {
	int type = sqlite3_column_type(this->parent.stmt.get(), index);
	if (type == SQLITE_NULL) return default_value;
	return sqlite3_column_int(this->parent.stmt.get(), index);
}
template <>
int DBQueryRow::col<int>(int index) const {
	return this->col<int>(index, 0);
}

DBQueryRowRange DBStatement::rows() {
	return { *this };
}

DBQueryRowRange::DBQueryRowIterator & DBQueryRowRange::DBQueryRowIterator::operator ++ () {
	int ret = sqlite3_step(this->parent.parent.stmt.get());
	if (ret == SQLITE_DONE) {
		this->end = true;
		return *this;
	}
	if (ret != SQLITE_ROW)
		throw Exception("sqlite3_step: %d", ret);
	return *this;
}

bool DBQueryRowRange::DBQueryRowIterator::operator != (const DBQueryRowIterator &) const {
	return !this->end;
}

DBQueryRow & DBQueryRowRange::DBQueryRowIterator::operator * () const {
	return this->parent.row;
}

DBQueryRowRange::DBQueryRowIterator DBQueryRowRange::begin() {
	DBQueryRowRange::DBQueryRowIterator it = { *this };
	return ++it;
}

DBQueryRowRange::DBQueryRowIterator DBQueryRowRange::end() {
	return { *this };
}

DBQueryRowRange::DBQueryRowRange(DBStatement & parent) : parent(parent), row(parent) { }

DBQueryRowRange::DBQueryRowIterator::DBQueryRowIterator(DBQueryRowRange & parent) : parent(parent) { }