package main

import (
	"testing"

	"github.com/novox/mesh-controller/internal/inventory"
)

// The holder of the build seat follows the controller that defines its worker (novox/hq issue 206).
// On 2026-10-03 a plan put the build machine in tier 0 and the controller in tier 1; the new build
// machine could not bind the worker the old controller had defined, and nothing could build the
// controller that would have redefined it. The built-by edge from the controller to its build
// machine yields to that order: the controller is built by whichever build machine is running.
func TestTheBuildSeatsHolderFollowsTheControllerThatDefinesItsWorker(t *testing.T) {
	edges := []inventory.Edge{
		{From: "build-agent", To: "mesh-controller", Kind: inventory.EdgePackages},
		{From: "build-agent", To: "mesh-controller", Kind: inventory.EdgeWorkerOf},
		{From: "mesh-controller", To: "build-agent", Kind: inventory.EdgeBuiltBy},
		{From: "route-proxy", To: "mesh-controller", Kind: inventory.EdgePackages},
		{From: "route-proxy", To: "build-agent", Kind: inventory.EdgeBuiltBy},
	}
	// A packages edge recorded before novox/hq ADR 0267 widens nothing: the controller moved alone moves
	// alone, and a change to a package all three build from moves all three, each by its own build source.
	if alone := reachableFrom([]string{"mesh-controller"}, edges); len(alone) != 1 {
		t.Fatalf("the controller alone, whatever packages its repository: %v", alone)
	}
	set := reachableFrom([]string{"mesh-controller", "build-agent", "route-proxy"}, edges)
	tiers := tiersOf(set, edges)
	pos := map[string]int{}
	for i, tier := range tiers {
		for _, m := range tier {
			pos[m] = i
		}
	}
	if pos["mesh-controller"] != 0 {
		t.Fatalf("the controller first, built by the build machine that is running: %v", tiers)
	}
	if pos["build-agent"] <= pos["mesh-controller"] {
		t.Fatalf("the build machine after the controller that defines its worker: %v", tiers)
	}
	// Built-by orders nothing (novox/hq ADR 0360 §3): whichever builder runs builds the proxy, beside the controller.
	if pos["route-proxy"] != 0 {
		t.Fatalf("what the builder builds waits for a new one: %v", tiers)
	}
	if hasCycle(tiers, edges) {
		t.Fatalf("no cycle here: %v", tiers)
	}
}