package services

// Unit tests for the extractor-version (ev) mechanism (faceted plan
// Phase 10): the wire normalization (absent = v1-or-unknown = 1) and the
// per-scan catch-up budget. The full scan-state machine (ev mismatch →
// re-extract once → stable) lives in cmd/server/tests
// (TestExtractorVersionReextract) because the store paths need a real DB.

import (
	"testing"
)

func TestManifestEvNormalization(t *testing.T) {
	if got := manifestEv(nil); got != 1 {
		t.Errorf("nil manifest rides v1: got %d, want 1", got)
	}
	cases := []struct {
		raw  string
		want int
	}{
		{`{"v":1}`, 1},          // old shape: ev absent → v1-or-unknown
		{`{"v":1,"ev":0}`, 1},   // explicitly unset → same
		{`{"v":1,"ev":1}`, 1},   // baseline parser stamp
		{`{"v":1,"ev":2}`, 2},   // post-bump stamp
		{`{"v":1,"entries":[],"ev":3}`, 3}, // sidecar-less ev home
	}
	for _, tc := range cases {
		m := decodeSidecarManifest([]byte(tc.raw))
		if m == nil {
			t.Fatalf("%s must decode", tc.raw)
		}
		if got := manifestEv(m); got != tc.want {
			t.Errorf("manifestEv(%s) = %d, want %d", tc.raw, got, tc.want)
		}
	}
}

func TestEvBudgetTake(t *testing.T) {
	scanner := &MediaScanner{}
	scanner.evBudgetRemaining.Store(2)
	if !scanner.evBudgetTake() {
		t.Error("budget 2: first take must pass")
	}
	if !scanner.evBudgetTake() {
		t.Error("budget 1: second take must pass")
	}
	if scanner.evBudgetTake() {
		t.Error("budget 0: third take must fail")
	}
	if got := scanner.evBudgetRemaining.Load(); got != 0 {
		t.Errorf("budget must land at exactly 0, got %d", got)
	}
}

func TestEvBudgetTake_FailsFastAtZero(t *testing.T) {
	scanner := &MediaScanner{}
	scanner.evBudgetRemaining.Store(0)
	// Repeated takes at 0 must fail WITHOUT driving the counter negative
	// (the CAS loop only fires when cur > 0).
	for i := 0; i < 5; i++ {
		if scanner.evBudgetTake() {
			t.Fatalf("take %d must fail at budget 0", i+1)
		}
	}
	if got := scanner.evBudgetRemaining.Load(); got != 0 {
		t.Errorf("budget must stay 0, got %d", got)
	}
}