// Copyright (C) 2016 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include <dhcpsrv/pgsql_exchange.h>

#include <boost/lexical_cast.hpp>

#include <iomanip>
#include <sstream>
#include <vector>

namespace isc {
namespace dhcp {

const int PsqlBindArray::TEXT_FMT = 0;
const int PsqlBindArray::BINARY_FMT = 1;
const char* PsqlBindArray::TRUE_STR = "TRUE";
const char* PsqlBindArray::FALSE_STR = "FALSE";

void PsqlBindArray::add(const char* value) {
    values_.push_back(value);
    lengths_.push_back(strlen(value));
    formats_.push_back(TEXT_FMT);
}

void PsqlBindArray::add(const std::string& value) {
    values_.push_back(value.c_str());
    lengths_.push_back(value.size());
    formats_.push_back(TEXT_FMT);
}

void PsqlBindArray::add(const std::vector<uint8_t>& data) {
    values_.push_back(reinterpret_cast<const char*>(&(data[0])));
    lengths_.push_back(data.size());
    formats_.push_back(BINARY_FMT);
}

void PsqlBindArray::add(const uint8_t* data, const size_t len) {
    values_.push_back(reinterpret_cast<const char*>(&(data[0])));
    lengths_.push_back(len);
    formats_.push_back(BINARY_FMT);
}

void PsqlBindArray::add(const bool& value)  {
    add(value ? TRUE_STR : FALSE_STR);
}

void PsqlBindArray::add(const uint8_t& byte) {
    // We static_cast to an unsigned int, otherwise lexcial_cast may to
    // treat byte as a character, which yields "" for unprintable values 
    bindString(boost::lexical_cast<std::string>
                              (static_cast<unsigned int>(byte)));
}

void PsqlBindArray::add(const isc::asiolink::IOAddress& addr) {
    if (addr.isV4()) {
        bindString(boost::lexical_cast<std::string>
                   (static_cast<uint32_t>(addr)));
    } else {
        bindString(addr.toText());
    }
}

// eventually this should replace add(std::string)
void PsqlBindArray::bindString(const std::string& str) {
    bound_strs_.push_back(StringPtr(new std::string(str)));
    PsqlBindArray::add((bound_strs_.back())->c_str());
}

std::string PsqlBindArray::toText() const {
    std::ostringstream stream;
    for (int i = 0; i < values_.size(); ++i) {
        stream << i << " : ";
        if (formats_[i] == TEXT_FMT) {
            stream << "\"" << values_[i] << "\"" << std::endl;
        } else {
            const char *data = values_[i];
            if (lengths_[i] == 0) {
                stream << "empty" << std::endl;
            } else {
                stream << "0x";
                for (int i = 0; i < lengths_[i]; ++i) {
                    stream << std::setfill('0') << std::setw(2)
                           << std::setbase(16)
                           << static_cast<unsigned int>(data[i]);
                }
                stream << std::endl;
            }
        }
    }

    return (stream.str());
}

std::string
PgSqlExchange::convertToDatabaseTime(const time_t input_time) {
    struct tm tinfo;
    char buffer[20];
    localtime_r(&input_time, &tinfo);
    strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", &tinfo);
    return (std::string(buffer));
}

std::string
PgSqlExchange::convertToDatabaseTime(const time_t cltt,
                                     const uint32_t valid_lifetime) {
    // Calculate expiry time. Store it in the 64-bit value so as we can
    // detect overflows.
    int64_t expire_time_64 = static_cast<int64_t>(cltt)
                             + static_cast<int64_t>(valid_lifetime);

    // It has been observed that the PostgreSQL doesn't deal well with the
    // timestamp values beyond the DataSource::MAX_DB_TIME seconds since the
    // beginning of the epoch (around year 2038). The value is often
    // stored in the database but it is invalid when read back (overflow?).
    // Hence, the maximum timestamp value is restricted here.
    if (expire_time_64 > DatabaseConnection::MAX_DB_TIME) {
        isc_throw(isc::BadValue, "Time value is too large: " << expire_time_64);
    }

    return (convertToDatabaseTime(static_cast<time_t>(expire_time_64)));
}

time_t
PgSqlExchange::convertFromDatabaseTime(const std::string& db_time_val) {
    // Convert string time value to time_t
    time_t new_time;
    try  {
        new_time = (boost::lexical_cast<time_t>(db_time_val));
    } catch (const std::exception& ex) {
        isc_throw(BadValue, "Database time value is invalid: " << db_time_val);
    }

    return (new_time);
}

const char*
PgSqlExchange::getRawColumnValue(const PgSqlResult& r, const int row,
                                 const size_t col) const {
    const char* value = PQgetvalue(r, row, col);
    if (!value) {
        isc_throw(DbOperationError, "getRawColumnValue no data for :"
                    << getColumnLabel(col) << " row:" << row);
    }
    return (value);
}

void
PgSqlExchange::getColumnValue(const PgSqlResult& r, const int row,
                              const size_t col, bool &value) const {
    const char* data = getRawColumnValue(r, row, col);
    if (!strlen(data) || *data == 'f') {
        value = false;
    } else if (*data == 't') {
        value = true;
    } else {
        isc_throw(DbOperationError, "Invalid boolean data: " << data
                  << " for: " << getColumnLabel(col) << " row:" << row
                  << " : must be 't' or 'f'");
    }
}

void
PgSqlExchange::getColumnValue(const PgSqlResult& r, const int row,
                              const size_t col, uint8_t &value) const {
    const char* data = getRawColumnValue(r, row, col);
    try {
        // lexically casting as uint8_t doesn't convert from char
        // so we use uint16_t and implicitly convert.
        value = boost::lexical_cast<uint16_t>(data);
    } catch (const std::exception& ex) {
        isc_throw(DbOperationError, "Invalid uint8_t data: " << data
                  << " for: " << getColumnLabel(col) << " row:" << row
                  << " : " << ex.what());
    }
}

void
PgSqlExchange::convertFromBytea(const PgSqlResult& r, const int row,
                                const size_t col, uint8_t* buffer,
                                const size_t buffer_size,
                                size_t &bytes_converted) const {
    // Returns converted bytes in a dynamically allocated buffer, and
    // sets bytes_converted.
    unsigned char* bytes = PQunescapeBytea((const unsigned char*)
                                           (getRawColumnValue(r, row, col)),
                                           &bytes_converted);

    // Unlikely it couldn't allocate it but you never know.
    if (!bytes) {
        isc_throw (DbOperationError, "PQunescapeBytea failed for:"
                   << getColumnLabel(col) << " row:" << row);
    }

    // Make sure it's not larger than expected.
    if (bytes_converted > buffer_size) {
        // Free the allocated buffer first!
        PQfreemem(bytes);
        isc_throw (DbOperationError, "Converted data size: "
                   << bytes_converted << " is too large for: "
                   << getColumnLabel(col) << " row:" << row);
    }

    // Copy from the allocated buffer to caller's buffer the free up
    // the allocated buffer.
    memcpy(buffer, bytes, bytes_converted);
    PQfreemem(bytes);
}

std::string
PgSqlExchange::getColumnLabel(const size_t column) const {
    if (column > column_labels_.size()) {
        std::ostringstream os;
        os << "Unknown column:" << column;
        return (os.str());
    }

    return (column_labels_[column]);
}

}; // end of isc::dhcp namespace
}; // end of isc namespace