package bootstrap

import (
	"context"
	"errors"
	"strings"
	"testing"
	"time"

	"github.com/novox/mesh-host/internal/declaration"
)

// Retirement is destruction by omission, which is the host's ordinary behaviour: it owns what it
// applied and removes what it owns and is no longer declared. These tests defend the bundle
// surgery that expresses it, because a bundle that came out of it unparseable would be found by
// the apply — after the file on the machine had already been replaced.

func produced(t *testing.T) []byte {
	t.Helper()
	out, err := Rewrite(theRealBundle(t), held)
	if err != nil {
		t.Fatal(err)
	}
	return out.Bundle
}

// The temporary control plane leaves the bundle, everything else stays, and what is left parses.
func TestTheTemporaryControlPlaneLeavesTheBundleAndNothingElseDoes(t *testing.T) {
	before, err := declaration.ParseFileTrusted(produced(t))
	if err != nil {
		t.Fatal(err)
	}
	shorter, err := removeResource(produced(t), ControlPlaneID)
	if err != nil {
		t.Fatal(err)
	}
	after, err := declaration.ParseFileTrusted(shorter)
	if err != nil {
		t.Fatalf("the bundle without the control plane does not parse: %v\n%s", err, shorter)
	}
	if len(after.Resources) != len(before.Resources)-1 {
		t.Fatalf("the bundle went from %d resources to %d, and one was removed",
			len(before.Resources), len(after.Resources))
	}
	if _, err := controlPlaneIn(after); err == nil {
		t.Error("the bundle still declares a control plane")
	}
	// The store and the broker are still exactly what they were. A retirement that took the
	// substrate with it would leave the machine with a module and nothing under it.
	for id, name := range containerNames(before) {
		if id == ControlPlaneID {
			continue
		}
		if containerNames(after)[id] != name {
			t.Errorf("%s was lost or renamed by the retirement", id)
		}
	}
}

// **A `//` inside a string is not a comment.** The substrate's own bundle carries
// `postgres://…` several times, and a scanner that read the rest of those lines as a comment
// would lose braces and cut the wrong thing out — silently, because what it produced would still
// look like a file.
func TestASchemeInsideAStringIsNotReadAsAComment(t *testing.T) {
	shorter, err := removeResource(produced(t), ControlPlaneID)
	if err != nil {
		t.Fatal(err)
	}
	after, err := declaration.ParseFileTrusted(shorter)
	if err != nil {
		t.Fatal(err)
	}
	// The migration action, which is the resource holding the most `://` of anything here, is
	// still whole.
	found := false
	for _, r := range after.Resources {
		if r.Identity() == "context-schemas" {
			found = true
		}
	}
	if !found {
		t.Error("the resource full of connection strings did not survive the removal")
	}
}

// Removing the FIRST element takes the comma after it rather than the comma before it, because
// there is no comma before it. Getting this wrong produces a leading comma, which is JSON nothing
// parses — and the file would already have been written.
func TestRemovingTheFirstResourceLeavesAValidList(t *testing.T) {
	shorter, err := removeResource(produced(t), "container-runtime")
	if err != nil {
		t.Fatal(err)
	}
	after, err := declaration.ParseFileTrusted(shorter)
	if err != nil {
		t.Fatalf("removing the first resource broke the bundle: %v\n%s", err, shorter)
	}
	for _, r := range after.Resources {
		if r.Identity() == "container-runtime" {
			t.Error("the first resource is still there")
		}
	}
}

// A bundle that declares no such resource is refused rather than silently returned unchanged. A
// removal that removed nothing and reported success would leave the apply below with nothing to
// do and the installer claiming a pivot it did not finish.
func TestRemovingSomethingThatIsNotThereIsRefused(t *testing.T) {
	if _, err := removeResource(produced(t), "nothing-of-the-sort"); err == nil {
		t.Fatal("a bundle was reported to have had a resource removed that it never declared")
	}
}

// A re-run after the retirement finds a bundle with no control plane in it and says so, rather
// than failing. This is the idempotence of the last step, and it is the one a person is most
// likely to exercise: the pivot ends here, so a re-run to check ends here too.
func TestRetiringABundleThatAlreadyHasNoControlPlaneIsAlreadyDone(t *testing.T) {
	shorter, err := removeResource(produced(t), ControlPlaneID)
	if err != nil {
		t.Fatal(err)
	}
	var said []string
	out, err := RetireTheTemporaryControlPlane(context.Background(), Options{},
		nil, shorter, nil, func(line string) { said = append(said, line) })
	if err != nil {
		t.Fatal(err)
	}
	if !out.Already {
		t.Error("a bundle with no control plane in it was not reported as already retired")
	}
	if !strings.Contains(strings.Join(said, "\n"), "already dropped") {
		t.Errorf("the run does not say it was already done: %v", said)
	}
}

// A container the runtime still knows about after the apply is a pivot that did not finish. Two
// control planes on one mesh are both correct and neither is wrong — but the temporary one was
// supposed to go, and saying it went when it did not is the fault this project keeps naming.
func TestAContainerStillThereAfterRemovalIsNotGone(t *testing.T) {
	previous := answerEvery
	answerEvery = time.Millisecond
	defer func() { answerEvery = previous }()

	stillThere := &asked{answer: func(_ string, _ []string) (string, error) {
		return "true running\n", nil
	}}
	gone, err := isGone(context.Background(), stillThere.run, time.Second, 0, "temp-mesh-control")
	if err != nil {
		t.Fatal(err)
	}
	if gone {
		t.Error("a container the runtime still describes was reported gone")
	}

	removed := &asked{answer: func(_ string, _ []string) (string, error) {
		return "", errors.New("No such object: temp-mesh-control")
	}}
	gone, err = isGone(context.Background(), removed.run, time.Second, 0, "temp-mesh-control")
	if err != nil {
		t.Fatal(err)
	}
	if !gone {
		t.Error("a container the runtime does not know about was not reported gone")
	}
}