package api

import (
	"context"
	"os"
	"path/filepath"
	"testing"
)

// fakeDocker puts a `docker` on PATH whose `image inspect` answers with the given RepoDigests.
func fakeDocker(t *testing.T, digests string) {
	t.Helper()
	dir := t.TempDir()
	script := "#!/bin/sh\necho '" + digests + "'\n"
	if err := os.WriteFile(filepath.Join(dir, "docker"), []byte(script), 0o755); err != nil {
		t.Fatal(err)
	}
	t.Setenv("PATH", dir)
}

// An update pulls the newer image: the cached registry answer must not keep calling it behind.
func TestSettledSeesAPulledImage(t *testing.T) {
	cached := []imageCheck{
		{Image: "nginx:alpine", State: "update", remote: "sha256:new"},
		{Image: "redis:7", State: "current", remote: "sha256:r"},
		{Image: "local/thing", State: "unknown"},
	}
	fakeDocker(t, `["nginx@sha256:new"]`)
	got := settled(context.Background(), cached)
	if got[0].State != "current" {
		t.Fatalf("pulled image still marked %q", got[0].State)
	}
	if got[1].State != "current" || got[2].State != "unknown" {
		t.Fatalf("others changed: %+v", got)
	}
	if cached[0].State != "update" {
		t.Fatal("settled wrote through to the cache")
	}
}

func TestSettledKeepsAnImageStillBehind(t *testing.T) {
	fakeDocker(t, `["nginx@sha256:old"]`)
	got := settled(context.Background(), []imageCheck{{Image: "nginx:alpine", State: "update", remote: "sha256:new"}})
	if got[0].State != "update" {
		t.Fatalf("image not yet pulled marked %q", got[0].State)
	}
}