/* -----------------------------------------------------------------------------
Copyright 2019-2021 Kevin P. Barry

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
----------------------------------------------------------------------------- */

// Author: Kevin P. Barry [ta0kira@gmail.com]

define AutoReadIterator {
  @value ReadAt<#x> container
  @value Int position

  from (container) {
    return fromOffset<#y>(container,0)
  }

  fromOffset (container,position) {
    Int position2 <- position
    if (position < 0) {
      position2 <- -1
    }
    if (position >= container.size() || container.size() == 0) {
      position2 <- container.size()
    }
    return AutoReadIterator<#y>{ container, position }
  }

  readCurrent () {
    if (pastForwardEnd() || pastReverseEnd()) {
      \ LazyStream<Formatted>.new()
          .append("Position ")
          .append(position)
          .append(" is out of bounds")
          .writeTo(SimpleOutput.error())
    }
    return container.readAt(position)
  }

  forward () {
    return fromOffset<#x>(container,position+1)
  }

  pastForwardEnd () {
    return position >= container.size()
  }

  reverse () {
    return fromOffset<#x>(container,position-1)
  }

  pastReverseEnd () {
    return position < 0 || container.size() == 0
  }
}

define AutoWriteIterator {
  @value WriteAt<#x> container
  @value Int position

  from (container) {
    return fromOffset<#y>(container,0)
  }

  fromOffset (container,position) {
    Int position2 <- position
    if (position < 0) {
      position2 <- -1
    }
    if (position >= container.size() || container.size() == 0) {
      position2 <- container.size()
    }
    return AutoWriteIterator<#y>{ container, position }
  }

  writeCurrent (x) {
    if (pastForwardEnd() || pastReverseEnd()) {
      \ LazyStream<Formatted>.new()
          .append("Position ")
          .append(position)
          .append(" is out of bounds")
          .writeTo(SimpleOutput.error())
    }
    \ container.writeAt(position,x)
    return self
  }

  forward () {
    return fromOffset<#x>(container,position+1)
  }

  pastForwardEnd () {
    return position >= container.size()
  }

  reverse () {
    return fromOffset<#x>(container,position-1)
  }

  pastReverseEnd () {
    return position < 0 || container.size() == 0
  }
}

define AutoIterator {
  @value [ReadAt<#x>&WriteAt<#x>] container
  @value Int position

  from (container) {
    return fromOffset<#y>(container,0)
  }

  fromOffset (container,position) {
    Int position2 <- position
    if (position < 0) {
      position2 <- -1
    }
    if (position >= container.size() || container.size() == 0) {
      position2 <- container.size()
    }
    return AutoIterator<#y>{ container, position }
  }

  readCurrent () {
    if (pastForwardEnd() || pastReverseEnd()) {
      \ LazyStream<Formatted>.new()
          .append("Position ")
          .append(position)
          .append(" is out of bounds")
          .writeTo(SimpleOutput.error())
    }
    return container.readAt(position)
  }

  writeCurrent (x) {
    if (pastForwardEnd() || pastReverseEnd()) {
      \ LazyStream<Formatted>.new()
          .append("Position ")
          .append(position)
          .append(" is out of bounds")
          .writeTo(SimpleOutput.error())
    }
    \ container.writeAt(position,x)
    return self
  }

  forward () {
    return fromOffset<#x>(container,position+1)
  }

  pastForwardEnd () {
    return position >= container.size()
  }

  reverse () {
    return fromOffset<#x>(container,position-1)
  }

  pastReverseEnd () {
    return position < 0 || container.size() == 0
  }
}