package appbackup

import "testing"

// TestDeriveStackName_KnownCrossRef asserts M19: deriveStackName cross-references the deployed-stack set
// so a stack whose slug ends in a DB-role token (e.g. `my-cache`) is NOT misattributed by pure
// suffix-stripping. The `my-cache` case fails on the pre-fix code (which stripped it to `my`).
func TestDeriveStackName_KnownCrossRef(t *testing.T) {
	known := map[string]bool{"romm": true, "my-cache": true, "paperless-ngx": true}

	cases := []struct {
		container string
		want      string
		note      string
	}{
		{"romm-postgres", "romm", "role suffix of a real stack → strip"},
		{"my-cache", "my-cache", "container name IS a real stack → do NOT strip to 'my'"}, // pre-fix: "my"
		{"my-cache-postgres", "my-cache", "strip role, result is a known stack"},          // pre-fix: "my-cache" (ok) — but via prefix here
		{"paperless-ngx-postgres", "paperless-ngx", "multi-hyphen stack, role suffix"},
		{"romm_postgres", "romm", "underscore-separated compose name → longest known prefix"},
		{"romm-1", "romm", "compose numeric suffix → longest known prefix"},
	}
	for _, c := range cases {
		if got := deriveStackName(c.container, known); got != c.want {
			t.Errorf("deriveStackName(%q, known) = %q, want %q (%s)", c.container, got, c.want, c.note)
		}
	}
}

// TestDeriveStackName_LegacyFallback asserts the nil/empty-known fast path preserves the old behaviour
// (pure suffix-strip), so callers without a stack list (e.g. appexport) don't regress.
func TestDeriveStackName_LegacyFallback(t *testing.T) {
	cases := []struct {
		container string
		want      string
	}{
		{"romm-postgres", "romm"},
		{"paperless-ngx-postgres", "paperless-ngx"},
		{"my-cache", "my"},        // legacy strips the role-token suffix
		{"unknown-db", "unknown"}, // legacy strip
		{"standalone", "standalone"},
	}
	for _, c := range cases {
		if got := deriveStackName(c.container, nil); got != c.want {
			t.Errorf("deriveStackName(%q, nil) = %q, want %q (legacy)", c.container, got, c.want)
		}
		// empty (non-nil) map must behave identically to nil
		if got := deriveStackName(c.container, map[string]bool{}); got != c.want {
			t.Errorf("deriveStackName(%q, {}) = %q, want %q (legacy)", c.container, got, c.want)
		}
	}
}

// TestDeriveStackName_UnknownContainerFallsBack asserts that when the container matches no known stack at
// all, the result falls back to the suffix-strip candidate (no spurious prefix match).
func TestDeriveStackName_UnknownContainerFallsBack(t *testing.T) {
	known := map[string]bool{"romm": true}
	if got := deriveStackName("grafana-db", known); got != "grafana" {
		t.Fatalf("deriveStackName(grafana-db, {romm}) = %q, want grafana (fallback strip)", got)
	}
	// must NOT match "romm" as a prefix of an unrelated name
	if got := deriveStackName("rommother-db", known); got != "rommother" {
		t.Fatalf("deriveStackName(rommother-db) = %q, want rommother (no false prefix match)", got)
	}
}
