# Real-router extension: push `bmp server 2` to every lab router pointing
# at the test collector, so real-router BMP output flows into the test
# stack alongside the internal gobgp synthetic feed. Nothing touches
# `bmp server 1` (production).
#
# Two-step safety: first apply is a DRY RUN (prints per-router pending
# diffs, does not commit). Set `confirm_router_push=true` and re-apply
# to actually commit the config on all routers.
#
# Lifecycle:
#   enable_router_bmp=false  -> resource absent, no router-side changes
#   enable=true, confirm=false -> dry-run provisioner (safe; abort at end)
#   enable=true, confirm=true  -> apply provisioner (commits + verifies)
#   flip either back           -> destroy provisioner runs `remove` (idempotent)
#
# The destroy provisioner uses `on_failure = continue` so a partial router
# outage never blocks the VM teardown in scripts/teardown.sh.

variable "enable_router_bmp" {
  description = "Enable the real-router BMP extension (push bmp server 2 to lab routers)."
  type        = bool
  default     = false
}

variable "confirm_router_push" {
  description = "Set to true on second apply to actually commit `bmp server 2` on routers. First apply (false) is a dry-run only."
  type        = bool
  default     = false
}

locals {
  router_bmp_action = var.confirm_router_push ? "apply" : "dry-run"
  router_bmp_script = abspath("${path.module}/../scripts/router_bmp.py")

  # The collector's address on the routers' management path. With DHCP,
  # this only becomes known after the store VM's guest-agent reports.
  router_bmp_target = try(
    proxmox_virtual_environment_vm.store.ipv4_addresses[1][0],
    ""
  )
}

resource "terraform_data" "router_bmp" {
  count = var.enable_router_bmp ? 1 : 0

  # Any change to these values REPLACES the resource -- destroy provisioner
  # runs first (removes any prior state on routers), then create provisioner
  # runs (applies the new state). That gives us clean transitions:
  # dry-run -> apply, or apply -> dry-run.
  triggers_replace = [
    local.router_bmp_action,
    local.router_bmp_target,
    var.router_facing_port,
  ]

  # `input` is available to provisioners as `self.input`.
  input = {
    action      = local.router_bmp_action
    script      = local.router_bmp_script
    target_ip   = local.router_bmp_target
    target_port = tostring(var.router_facing_port)
  }

  # CREATE (or replace): push (or dry-run) `bmp server 2` to all routers.
  provisioner "local-exec" {
    command = "python3 ${self.input.script} ${self.input.action} --target-ip ${self.input.target_ip} --target-port ${self.input.target_port}"
  }

  # DESTROY: remove `bmp server 2` from all routers. Idempotent: routers
  # without the config are no-ops. `on_failure = continue` so a single
  # unreachable router does not block the VM teardown.
  provisioner "local-exec" {
    when       = destroy
    on_failure = continue
    command    = "python3 ${self.input.script} remove --target-ip ${self.input.target_ip} --target-port ${self.input.target_port}"
  }
}

output "router_bmp_status" {
  description = "Real-router BMP extension state."
  value = var.enable_router_bmp ? {
    enabled        = true
    action         = local.router_bmp_action
    confirm_needed = !var.confirm_router_push
    target         = "${local.router_bmp_target}:${var.router_facing_port}"
    hint           = var.confirm_router_push ? "committed on last apply; destroy will remove" : "set confirm_router_push=true and re-apply to commit"
    } : {
    enabled = false
    hint    = "set enable_router_bmp=true (and later confirm_router_push=true) to add bmp server 2 to lab routers"
  }
}