package backup

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

func writeKeptUnit(t *testing.T, unitDir, hdd string, withData bool, at time.Time) {
	t.Helper()
	if err := os.MkdirAll(filepath.Join(unitDir, "compose"), 0o755); err != nil {
		t.Fatal(err)
	}
	man := RecoveryManifest{SchemaVersion: 2, AppName: "nextcloud"}
	if withData {
		man.DBDumps = []string{"nextcloud-mariadb.sql"}
	}
	b, _ := json.Marshal(man)
	if err := os.WriteFile(UnitManifestFile(unitDir), b, 0o644); err != nil {
		t.Fatal(err)
	}
	_ = os.Chtimes(UnitManifestFile(unitDir), at, at)
	if hdd != "" {
		if err := os.WriteFile(filepath.Join(unitDir, "compose", "app.yaml"), []byte("env:\n  HDD_PATH: "+hdd+"\n"), 0o600); err != nil {
			t.Fatal(err)
		}
	}
}

// `09` §3 decision 36 — „use my kept data" loads only a copy that (1) holds the app's data and (2) was
// taken of THIS drive's install; the newest such copy on any local tier wins.
// COMPANION RED-PROOF: drop the HDD_PATH comparison in KeptCopyAt → a unit taken of ANOTHER drive is
// offered and the first assertion fails.
func TestKept_DBCopyIsTheNewestUsableForThisDrive(t *testing.T) {
	m, sett, drive := r690Manager(t)
	_ = sett
	unit := RecoveryUnitPath(m.namespaceRoot(drive), "nextcloud")

	writeKeptUnit(t, unit, "/mnt/felhom-drives/other", true, time.Now().Add(-time.Hour))
	if c, ok := m.KeptDBCopy("nextcloud", drive); ok {
		t.Fatalf("a unit taken of another drive was offered: %+v", c)
	}
	writeKeptUnit(t, unit, drive, false, time.Now().Add(-time.Hour))
	if c, ok := m.KeptDBCopy("nextcloud", drive); ok {
		t.Fatalf("a unit holding no data was offered: %+v", c)
	}
	writeKeptUnit(t, unit, drive, true, time.Now().Add(-time.Hour))
	c, ok := m.KeptDBCopy("nextcloud", drive)
	if !ok || c.UnitDir != unit || c.Tier != 1 {
		t.Fatalf("own unit not offered: %+v ok=%v", c, ok)
	}
	// An INSTALLED app's unit is its live backup, never a kept-data offer.
	if c, ok := m.KeptDBCopy("still-here", drive); ok {
		t.Fatalf("an installed app's unit was offered: %+v", c)
	}
	// The start-fresh hook names the unit only on the same drive.
	if got := m.RemovedUnitOnDrive("nextcloud", drive); got != unit {
		t.Fatalf("RemovedUnitOnDrive = %q, want %q", got, unit)
	}
	if got := m.RemovedUnitOnDrive("nextcloud", "/elsewhere"); got != "" {
		t.Fatalf("RemovedUnitOnDrive named a unit on another drive: %q", got)
	}
}