package main

import (
	"context"
	"encoding/json"
	"errors"
	"testing"

	"git.novox.be/novox/mesh-sdk/go/delivery"
	"github.com/novox/mesh-host/internal/liveness"
)

// 1957/AC2 and AC4 (unit; ADR 0568 §2, §4): the judge's look acts on a resource that goes down, once per edge. A repeated
// statement acts nothing, the edge clears when the resource is healthy again, and a resource held, restarting, starting or
// missing (the other path's) is no edge.
func testOnlyAResourceNewlyDownIsAnEdge(t *testing.T) {
	state := func(id, s, reason string, missing bool) liveness.State {
		return liveness.State{Resource: liveness.Resource{Module: "dnsmasq", ID: id}, State: s, Reason: reason, Missing: missing}
	}
	down := state("dnsmasq.unit", liveness.Unhealthy, liveness.ReasonDown, false)
	steps := []struct {
		name string
		st   []liveness.State
		want []string
	}{
		{"down: an edge", []liveness.State{down}, []string{"dnsmasq"}},
		{"said again while down: none", []liveness.State{down}, nil},
		{"healthy again: clears", []liveness.State{state("dnsmasq.unit", liveness.Healthy, "", false)}, nil},
		{"down again: an edge", []liveness.State{down}, []string{"dnsmasq"}},
		{"held by a window: none", []liveness.State{state("dnsmasq.unit", liveness.Held, "", false)}, nil},
		{"restarting: none", []liveness.State{state("dnsmasq.unit", liveness.Unhealthy, liveness.ReasonRestarting, false)}, nil},
		{"starting: none", []liveness.State{state("dnsmasq.unit", liveness.Starting, "", false)}, nil},
		{"missing: the other path's", []liveness.State{state("dnsmasq.unit", liveness.Unhealthy, liveness.ReasonDown, true)}, nil},
	}
	var last map[string]bool
	for _, s := range steps {
		var got []string
		got, last = newlyInactive(last, liveness.Statement{Resources: s.st})
		if len(got) != len(s.want) || (len(got) == 1 && got[0] != s.want[0]) {
			t.Fatalf("%s: acted on %v, want %v", s.name, got, s.want)
		}
	}
}

type fakeRuntime struct {
	units      map[string]liveness.Observed
	containers map[string]liveness.Observed
	err        error
}

func (f fakeRuntime) Containers(_ context.Context, _ []string) (map[string]liveness.Observed, error) {
	return f.containers, f.err
}
func (f fakeRuntime) Units(_ context.Context, _, _ string, _ []string) (map[string]liveness.Observed, error) {
	return f.units, f.err
}

// 1957/AC1 (unit; ADR 0568 §1): the machine's facts say a declared-running resource is not active when its unit is stopped
// or unknown to the manager; everything up, a restart in progress, a read that failed and a container held by a
// maintenance window are not.
func testTheMachineShowsAResourceNotActive(t *testing.T) {
	svc := []byte(`{"id":"dnsmasq.unit","type":"service","unit":"dnsmasq.service","state":"running","module":"dnsmasq"}`)
	ctr := []byte(`{"id":"dnsmasq.box","type":"container","name":"box","image":"x@sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","module":"dnsmasq"}`)
	up := liveness.Observed{Found: true, Running: true}
	for _, c := range []struct {
		name string
		rt   fakeRuntime
		held map[string]bool
		want bool
	}{
		{"all up", fakeRuntime{units: map[string]liveness.Observed{"dnsmasq.service": up}, containers: map[string]liveness.Observed{"box": up}}, nil, false},
		{"unit inactive", fakeRuntime{units: map[string]liveness.Observed{"dnsmasq.service": {Found: true}}, containers: map[string]liveness.Observed{"box": up}}, nil, true},
		{"unit unknown to the manager", fakeRuntime{containers: map[string]liveness.Observed{"box": up}}, nil, true},
		{"unit restarting", fakeRuntime{units: map[string]liveness.Observed{"dnsmasq.service": {Found: true, Restarting: true}}, containers: map[string]liveness.Observed{"box": up}}, nil, false},
		{"container not running", fakeRuntime{units: map[string]liveness.Observed{"dnsmasq.service": up}, containers: map[string]liveness.Observed{"box": {Found: true}}}, nil, true},
		{"container held by a window", fakeRuntime{units: map[string]liveness.Observed{"dnsmasq.service": up}, containers: map[string]liveness.Observed{"box": {Found: true}}}, map[string]bool{"box": true}, false},
		{"unread", fakeRuntime{err: errors.New("the service manager could not be read")}, nil, false},
	} {
		t.Run(c.name, func(t *testing.T) {
			d, err := declarationOf(delivery.Composed{Node: "n1", Module: "dnsmasq", Resources: []json.RawMessage{svc, ctr}})
			if err != nil {
				t.Fatal(err)
			}
			if got := anyInactive(context.Background(), c.rt, liveness.LongRunning(d, nil), c.held); got != c.want {
				t.Fatalf("inactive = %v, want %v", got, c.want)
			}
		})
	}
}