No fields for transaction Fee

[vlasfama]

Describe the problem you'd like to have solved

Cannot find transaction fee details in API or gRPC Call

Describe the ideal solution

We need to create/add API/fee to calculate the total transaction fee.

[ZigBalthazar]

Hi @nagarajmanjunath , @b00f

Please provide more information and explanations (if possible, provide a scenario as well)
I can do this task

[b00f]

@ZigBalthazar

Thank you for your interest in this issue.

Transaction fees in the Pactus blockchain are calculated using a percentage-based fee model. You can learn more about this model here: https://pactus.org/learn/transaction/fee/. (It is a new idea to manage the transaction pool better).

Currently, when users create transactions with their wallets, the fee is calculated and set automatically). Users are not required to input it manually, even we have an option for manual fee input in the CLI.

For some offline queries, it would be beneficial to have an API that calculates transaction fees based on two parameters:

• Transaction Payload type
• Transactor value

We might have an API similar to: CalculateTransactionFee(payloadType payload.Type, amount int64) int64

[ZigBalthazar]

@b00f
thanks for providing a description, I will do this task and create a PR✌️

[b00f]

An Idea:
To calculate transaction fees, you need to know the consensus parameters such as the Minimum Fee and Maximum Fee.
Who has this knowledge? The State is fully aware of the consensus parameters.
Therefore, the best place for CalculateFee function inside the State.
The State can expose this function to outside world.

So this PR, hits two birds with one stone: make wallet less knowledgeable and add a new API for fee calculation.
Wallet can call the new gRPC API to get the fee.

@ZigBalthazar What is your thought?