package pipeline

import (
	"context"
	"net/http"
	"net/http/httptest"
	"sync/atomic"
	"testing"

	"evobgp/internal/store"
)

func TestCDNRefreshSameSetDoesNotRewriteOrRevise(t *testing.T) {
	t.Setenv("EVOBGP_CDN_ALLOW_PRIVATE", "1")
	m := store.NewMemory()
	m.SeedDemo()
	tenant, _, _, _, _ := m.DemoIDs()
	disabled := false
	for _, mod := range m.ListModules(tenant) {
		if mod == nil {
			continue
		}
		if _, err := m.UpdateModule(tenant, mod.ID, &store.ModulePatch{Enabled: &disabled}); err != nil {
			t.Fatal(err)
		}
	}

	var body atomic.Value
	body.Store("203.0.113.0/24\n198.51.100.0/24\n")
	srv := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = w.Write([]byte(body.Load().(string)))
	}))
	defer srv.Close()

	mod, err := m.CreateModule(tenant, &store.Module{Type: "CDN_CIDRS", Name: "cdn-order", Enabled: true})
	if err != nil {
		t.Fatal(err)
	}
	if _, err := m.CreateCDNSource(tenant, mod.ID, &store.CDNSource{SourceKind: "plain", URL: srv.URL}); err != nil {
		t.Fatal(err)
	}
	ctx := context.Background()
	if err := RefreshModuleIngest(ctx, m, srv.Client(), tenant, mod.ID); err != nil {
		t.Fatal(err)
	}
	snap1, ok, err := m.GetModulePrefixSnapshot(ctx, tenant, mod.ID)
	if err != nil || !ok || snap1 == nil {
		t.Fatalf("snapshot: ok=%v err=%v", ok, err)
	}
	gen1, err := m.GetRenderGeneration(ctx, tenant)
	if err != nil {
		t.Fatal(err)
	}

	if err := RefreshModuleIngest(ctx, m, srv.Client(), tenant, mod.ID); err != nil {
		t.Fatal(err)
	}
	snapSame, ok, err := m.GetModulePrefixSnapshot(ctx, tenant, mod.ID)
	if err != nil || !ok || snapSame == nil {
		t.Fatal(err)
	}
	genSame, err := m.GetRenderGeneration(ctx, tenant)
	if err != nil {
		t.Fatal(err)
	}
	if snapSame.Version != snap1.Version || !snapSame.CollectedAt.Equal(snap1.CollectedAt) || genSame != gen1 {
		t.Fatalf("unchanged CDN rewritten: version %d->%d gen %d->%d", snap1.Version, snapSame.Version, gen1, genSame)
	}

	body.Store("198.51.100.0/24\n203.0.113.0/24\n")
	if err := RefreshModuleIngest(ctx, m, srv.Client(), tenant, mod.ID); err != nil {
		t.Fatal(err)
	}
	snap2, ok, err := m.GetModulePrefixSnapshot(ctx, tenant, mod.ID)
	if err != nil || !ok || snap2 == nil {
		t.Fatal(err)
	}
	gen2, err := m.GetRenderGeneration(ctx, tenant)
	if err != nil {
		t.Fatal(err)
	}
	if snap2.Version != snap1.Version || !snap2.CollectedAt.Equal(snap1.CollectedAt) || gen2 != gen1 {
		t.Fatalf("reordered CDN rewritten: version %d->%d gen %d->%d", snap1.Version, snap2.Version, gen1, gen2)
	}
	if len(snap2.Prefixes) != len(snap1.Prefixes) || snap2.Prefixes[0].Prefix != snap1.Prefixes[0].Prefix {
		t.Fatalf("row order changed without a content change: %+v", snap2.Prefixes)
	}

	before, _, _ := m.ListRevisions(tenant, "", "", 50)
	rev1, err := RenderTenantRevision(ctx, m, srv.Client(), tenant, mod.ID)
	if err != nil {
		t.Fatal(err)
	}
	rev2, err := RenderTenantRevision(ctx, m, srv.Client(), tenant, mod.ID)
	if err != nil {
		t.Fatal(err)
	}
	if rev2 != rev1 {
		t.Fatalf("order-stable inputs created another revision: %s vs %s", rev1, rev2)
	}
	mid, _, _ := m.ListRevisions(tenant, "", "", 50)
	if len(mid) != len(before)+1 {
		t.Fatalf("revisions after unchanged renders: before=%d after=%d", len(before), len(mid))
	}

	body.Store("203.0.113.0/24\n192.0.2.0/24\n")
	if err := RefreshModuleIngest(ctx, m, srv.Client(), tenant, mod.ID); err != nil {
		t.Fatal(err)
	}
	rev3, err := RenderTenantRevision(ctx, m, srv.Client(), tenant, mod.ID)
	if err != nil {
		t.Fatal(err)
	}
	if rev3 == rev1 {
		t.Fatal("prefix change did not create a revision")
	}
	after, _, _ := m.ListRevisions(tenant, "", "", 50)
	if len(after) != len(mid)+1 {
		t.Fatalf("prefix change revisions: before=%d after=%d", len(mid), len(after))
	}
}