/*
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 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
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 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 */

/**
 * @file
 *   This file implements MechCop TLV helper functions.
 */

#include "meshcop_tlvs.hpp"

#include "common/const_cast.hpp"
#include "common/debug.hpp"
#include "common/num_utils.hpp"
#include "common/numeric_limits.hpp"
#include "common/string.hpp"
#include "meshcop/meshcop.hpp"

namespace ot {
namespace MeshCoP {

NameData NetworkNameTlv::GetNetworkName(void) const
{
    uint8_t len = GetLength();

    if (len > sizeof(mNetworkName))
    {
        len = sizeof(mNetworkName);
    }

    return NameData(mNetworkName, len);
}

void NetworkNameTlv::SetNetworkName(const NameData &aNameData)
{
    uint8_t len;

    len = aNameData.CopyTo(mNetworkName, sizeof(mNetworkName));
    SetLength(len);
}

bool NetworkNameTlv::IsValid(void) const { return IsValidUtf8String(mNetworkName, GetLength()); }

void SteeringDataTlv::CopyTo(SteeringData &aSteeringData) const
{
    aSteeringData.Init(GetSteeringDataLength());
    memcpy(aSteeringData.GetData(), mSteeringData, GetSteeringDataLength());
}

bool SecurityPolicyTlv::IsValid(void) const
{
    return GetLength() >= sizeof(mRotationTime) && GetFlagsLength() >= kThread11FlagsLength;
}

SecurityPolicy SecurityPolicyTlv::GetSecurityPolicy(void) const
{
    SecurityPolicy securityPolicy;
    uint8_t        length = Min(static_cast<uint8_t>(sizeof(mFlags)), GetFlagsLength());

    securityPolicy.mRotationTime = GetRotationTime();
    securityPolicy.SetFlags(mFlags, length);

    return securityPolicy;
}

void SecurityPolicyTlv::SetSecurityPolicy(const SecurityPolicy &aSecurityPolicy)
{
    SetRotationTime(aSecurityPolicy.mRotationTime);
    aSecurityPolicy.GetFlags(mFlags, sizeof(mFlags));
}

const char *StateTlv::StateToString(State aState)
{
    static const char *const kStateStrings[] = {
        "Pending", // (0) kPending,
        "Accept",  // (1) kAccept
        "Reject",  // (2) kReject,
    };

    static_assert(0 == kPending, "kPending value is incorrect");
    static_assert(1 == kAccept, "kAccept value is incorrect");

    return aState == kReject ? kStateStrings[2] : kStateStrings[aState];
}

uint32_t DelayTimerTlv::CalculateRemainingDelay(const Tlv &aDelayTimerTlv, TimeMilli aUpdateTime)
{
    uint32_t delay   = Min(aDelayTimerTlv.ReadValueAs<DelayTimerTlv>(), kMaxDelay);
    uint32_t elapsed = TimerMilli::GetNow() - aUpdateTime;

    if (delay > elapsed)
    {
        delay -= elapsed;
    }
    else
    {
        delay = 0;
    }

    return delay;
}

bool ChannelMaskTlv::IsValid(void) const
{
    uint32_t channelMask;

    return (ReadChannelMask(channelMask) == kErrorNone);
}

Error ChannelMaskTlv::ReadChannelMask(uint32_t &aChannelMask) const
{
    EntriesData entriesData;

    entriesData.Clear();
    entriesData.mData = &mEntriesStart;
    entriesData.mOffsetRange.Init(0, GetLength());

    return entriesData.Parse(aChannelMask);
}

Error ChannelMaskTlv::FindIn(const Message &aMessage, uint32_t &aChannelMask)
{
    Error       error;
    EntriesData entriesData;
    OffsetRange offsetRange;

    entriesData.Clear();
    entriesData.mMessage = &aMessage;

    SuccessOrExit(error = FindTlvValueOffsetRange(aMessage, Tlv::kChannelMask, offsetRange));
    entriesData.mOffsetRange = offsetRange;
    error                    = entriesData.Parse(aChannelMask);

exit:
    return error;
}

Error ChannelMaskTlv::EntriesData::Parse(uint32_t &aChannelMask)
{
    // Validates and parses the Channel Mask TLV entries for each
    // channel page and if successful updates `aChannelMask` to
    // return the combined mask for all channel pages supported by
    // radio. The entries can be either contained in `mMessage`
    // (when `mMessage` is non-null) or be in a buffer `mData`.

    Error        error = kErrorParse;
    Entry        readEntry;
    const Entry *entry;
    uint16_t     size;

    aChannelMask = 0;

    VerifyOrExit(!mOffsetRange.IsEmpty()); // At least one entry.

    while (!mOffsetRange.IsEmpty())
    {
        VerifyOrExit(mOffsetRange.Contains(kEntryHeaderSize));

        if (mMessage != nullptr)
        {
            // We first read the entry's header only and after
            // validating the entry and that the entry's channel page
            // is supported by radio, we read the full `Entry`.

            mMessage->ReadBytes(mOffsetRange.GetOffset(), &readEntry, kEntryHeaderSize);
            entry = &readEntry;
        }
        else
        {
            entry = reinterpret_cast<const Entry *>(&mData[mOffsetRange.GetOffset()]);
        }

        size = kEntryHeaderSize + entry->GetMaskLength();

        VerifyOrExit(mOffsetRange.Contains(size));

        if (Radio::SupportsChannelPage(entry->GetChannelPage()))
        {
            // Currently supported channel pages all use `uint32_t`
            // channel mask.

            VerifyOrExit(entry->GetMaskLength() == kMaskLength);

            if (mMessage != nullptr)
            {
                IgnoreError(mMessage->Read(mOffsetRange, readEntry));
            }

            aChannelMask |= (entry->GetMask() & Radio::ChannelMaskForPage(entry->GetChannelPage()));
        }

        mOffsetRange.AdvanceOffset(size);
    }

    error = kErrorNone;

exit:
    return error;
}

void ChannelMaskTlv::PrepareValue(Value &aValue, uint32_t aChannelMask)
{
    Entry *entry = reinterpret_cast<Entry *>(aValue.mData);

    aValue.mLength = 0;

    for (uint8_t page : Radio::kSupportedChannelPages)
    {
        uint32_t mask = (Radio::ChannelMaskForPage(page) & aChannelMask);

        if (mask != 0)
        {
            entry->SetChannelPage(page);
            entry->SetMaskLength(kMaskLength);
            entry->SetMask(mask);

            aValue.mLength += sizeof(Entry);
            entry++;
        }
    }
}

Error ChannelMaskTlv::AppendTo(Message &aMessage, uint32_t aChannelMask)
{
    Value value;

    PrepareValue(value, aChannelMask);
    return Tlv::Append<ChannelMaskTlv>(aMessage, value.mData, value.mLength);
}

} // namespace MeshCoP
} // namespace ot