//go:build linux

package instanceexec

import (
	"encoding/json"
	"os"
	"path/filepath"
	"testing"
	"time"

	"github.com/carlosframework/platform/internal/instancectl"
)

func envOf(m map[string]string) func(string) string {
	return func(k string) string { return m[k] }
}

func TestWriteExitRecordWritesTheFourVariables(t *testing.T) {
	run := t.TempDir()
	iid := "h.example.com"
	if err := os.MkdirAll(filepath.Join(run, "instances", iid), 0o700); err != nil {
		t.Fatal(err)
	}
	now := time.Date(2026, 9, 11, 12, 0, 0, 0, time.UTC)
	env := envOf(map[string]string{"INVOCATION_ID": "deadbeefdeadbeefdeadbeefdeadbeef", "SERVICE_RESULT": "exit-code", "EXIT_CODE": "exited", "EXIT_STATUS": "3"})
	if err := writeExitRecord(run, instancectl.RoleRun, iid, env, now); err != nil {
		t.Fatalf("writeExitRecord: %v", err)
	}
	b, err := os.ReadFile(filepath.Join(run, "instances", iid, "exit.run.deadbeefdeadbeefdeadbeefdeadbeef.json"))
	if err != nil {
		t.Fatal(err)
	}
	var rec instancectl.ExitRecord
	if err := json.Unmarshal(b, &rec); err != nil {
		t.Fatal(err)
	}
	if rec.Invocation != "deadbeefdeadbeefdeadbeefdeadbeef" || rec.Result != "exit-code" || rec.Code != "exited" || rec.Status != "3" || !rec.At.Equal(now) {
		t.Errorf("record = %+v", rec)
	}
	// 0600: the record is diagnostic detail about this instance's own exit,
	// not something every reader of the instance directory needs (final
	// review, plan 2, item 6).
	if fi, err := os.Stat(filepath.Join(run, "instances", iid, "exit.run.deadbeefdeadbeefdeadbeefdeadbeef.json")); err != nil || fi.Mode().Perm() != 0o600 {
		t.Errorf("mode = %v, %v, want 0600", fi.Mode(), err)
	}
	// O_EXCL: a second write for the same invocation is refused and the
	// first record stands.
	env2 := envOf(map[string]string{"INVOCATION_ID": "deadbeefdeadbeefdeadbeefdeadbeef", "SERVICE_RESULT": "success", "EXIT_CODE": "exited", "EXIT_STATUS": "0"})
	if err := writeExitRecord(run, instancectl.RoleRun, iid, env2, now); err == nil {
		t.Error("second write for the same invocation succeeded")
	}
	b2, _ := os.ReadFile(filepath.Join(run, "instances", iid, "exit.run.deadbeefdeadbeefdeadbeefdeadbeef.json"))
	if string(b2) != string(b) {
		t.Error("first record was overwritten")
	}
}

func TestWriteExitRecordWithoutInvocationIsANoop(t *testing.T) {
	run := t.TempDir()
	iid := "h.example.com"
	if err := os.MkdirAll(filepath.Join(run, "instances", iid), 0o700); err != nil {
		t.Fatal(err)
	}
	if err := writeExitRecord(run, instancectl.RoleSeed, iid, envOf(nil), time.Now()); err != nil {
		t.Fatalf("no INVOCATION_ID: %v (must not fail the unit's stop)", err)
	}
	entries, _ := os.ReadDir(filepath.Join(run, "instances", iid))
	if len(entries) != 0 {
		t.Errorf("wrote %v without an invocation id", entries)
	}
}

func TestWriteExitRecordRefusesAnInvocationThatIsNotAName(t *testing.T) {
	run := t.TempDir()
	iid := "h.example.com"
	if err := os.MkdirAll(filepath.Join(run, "instances", iid), 0o700); err != nil {
		t.Fatal(err)
	}
	env := envOf(map[string]string{"INVOCATION_ID": "../../etc/x", "SERVICE_RESULT": "success"})
	if err := writeExitRecord(run, instancectl.RoleRun, iid, env, time.Now()); err == nil {
		t.Error("an invocation id with a path separator was accepted")
	}
}

func TestWriteExitRecordKeysAGenerationRecordByGeneration(t *testing.T) {
	run := t.TempDir()
	iid := "h.example.com"
	if err := os.MkdirAll(filepath.Join(run, "instances", iid), 0o700); err != nil {
		t.Fatal(err)
	}
	now := time.Date(2026, 10, 7, 12, 0, 0, 0, time.UTC)
	env := envOf(map[string]string{"INVOCATION_ID": "deadbeefdeadbeefdeadbeefdeadbeef", "SERVICE_RESULT": "success", "EXIT_CODE": "exited", "EXIT_STATUS": "0"})
	if err := writeExitRecord(run, instancectl.RoleRun, instancectl.GenInstance(iid, 7), env, now); err != nil {
		t.Fatalf("writeExitRecord: %v", err)
	}
	if _, err := os.Stat(filepath.Join(run, "instances", iid, "exit.gen.7.deadbeefdeadbeefdeadbeefdeadbeef.json")); err != nil {
		t.Errorf("generation record missing: %v", err)
	}
	if _, err := os.Stat(filepath.Join(run, "instances", iid, "exit.run.deadbeefdeadbeefdeadbeefdeadbeef.json")); !os.IsNotExist(err) {
		t.Errorf("a generation wrote a legacy record: %v", err)
	}
	if err := writeExitRecord(run, instancectl.RoleSidecar, iid+":7", env, now); err == nil {
		t.Error("a sidecar generation was accepted")
	}
}