resource "aws_internet_gateway" "this" {
  count = var.create_vpc ? 1 : 0

  vpc_id = aws_vpc.this[0].id

  tags = merge(
    local.common_tags,
    {
      Name = "${var.name}-igw"
    }
  )
}

resource "aws_eip" "nat" {
  for_each = var.create_vpc ? (var.single_nat_gateway ? { shared = local.azs[0] } : { for az in local.azs : az => az }) : {}

  domain = "vpc"

  tags = merge(
    local.common_tags,
    {
      Name = "${var.name}-nat-eip-${each.key}"
    }
  )
}

resource "aws_nat_gateway" "this" {
  for_each = var.create_vpc ? (var.single_nat_gateway ? { shared = local.azs[0] } : { for az in local.azs : az => az }) : {}

  allocation_id = aws_eip.nat[each.key].id
  subnet_id     = aws_subnet.public[each.value].id

  tags = merge(
    local.common_tags,
    {
      Name = "${var.name}-nat-${each.key}"
    }
  )

  depends_on = [aws_internet_gateway.this]
}

resource "aws_route_table" "public" {
  count = var.create_vpc ? 1 : 0

  vpc_id = aws_vpc.this[0].id

  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = aws_internet_gateway.this[0].id
  }

  tags = merge(
    local.common_tags,
    {
      Name = "${var.name}-public-rt"
    }
  )
}

resource "aws_route_table_association" "public" {
  for_each = var.create_vpc ? aws_subnet.public : {}

  subnet_id      = each.value.id
  route_table_id = aws_route_table.public[0].id
}

resource "aws_route_table" "private" {
  for_each = var.create_vpc ? aws_subnet.private : {}

  vpc_id = aws_vpc.this[0].id

  route {
    cidr_block     = "0.0.0.0/0"
    nat_gateway_id = aws_nat_gateway.this[var.single_nat_gateway ? "shared" : each.key].id
  }

  tags = merge(
    local.common_tags,
    {
      Name = "${var.name}-private-rt-${each.key}"
    }
  )
}

resource "aws_route_table_association" "private" {
  for_each = var.create_vpc ? aws_subnet.private : {}

  subnet_id      = each.value.id
  route_table_id = aws_route_table.private[each.key].id
}