module Initial.Cash where

import DA.Assert

template Position
  with
    issuer : Party
    owner : Party
    quantity : Decimal
    obs : [Party]
  where
    signatory [issuer, owner]
    observer obs
    ensure quantity > 0.0

    choice Transfer : ContractId Position
      with
        newOwner : Party
      controller [owner, newOwner]
      do
        create this with 
          owner = newOwner
          obs = []

    choice Propose_Transfer : ContractId TransferProposal
      with
        newOwner : Party
      controller owner
      do
        create TransferProposal with 
          position = this
          newOwner

    choice Split : (ContractId  Position, [ContractId Position])
      with
        splitQuantities : [Decimal]
      controller owner
      do
        remCid <- create this with quantity = this.quantity -  sum splitQuantities
        splitCids <- forA splitQuantities (\splitQuantity -> create this with
            quantity = splitQuantity
          )
        return (remCid, splitCids)

    choice Merge : ContractId Position
      with
        otherCids : [ContractId Position]
      controller owner
      do
        quantities <- forA otherCids (\otherCid -> do
          other <- fetch otherCid
          other === this with 
            quantity = other.quantity
            obs = other.obs
          archive otherCid
          return other.quantity)
        create this with
          quantity = quantity + sum quantities

template TransferProposal
  with
    position : Position
    newOwner : Party
  where
    signatory (signatory position)
    observer newOwner::(observer position)

    choice Accept : ContractId Position
      controller newOwner
      do
        create position with
          owner = newOwner
          obs = []

    choice Cancel : ContractId Position
      controller position.owner
      do
        create position