package pipeline

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

	"evobgp/internal/store"
)

func TestCollectModulePrefixRows_CDNSendsIfNoneMatch(t *testing.T) {
	t.Setenv("EVOBGP_CDN_ALLOW_PRIVATE", "1")
	m := store.NewMemory()
	m.SeedDemo()
	tenant, _, _, _, _ := m.DemoIDs()

	mod, err := m.CreateModule(tenant, &store.Module{
		Type:    "CDN_CIDRS",
		Name:    "cdn-conditional",
		Enabled: true,
	})
	if err != nil {
		t.Fatal(err)
	}

	var gotIfNoneMatch string
	srv := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotIfNoneMatch = strings.TrimSpace(r.Header.Get("If-None-Match"))
		w.Header().Set("ETag", "etag-new")
		_, _ = w.Write([]byte("198.51.100.0/24\n"))
	}))
	defer srv.Close()

	etag := "etag-old"
	if _, err := m.CreateCDNSource(tenant, mod.ID, &store.CDNSource{
		SourceKind: "txt",
		URL:        srv.URL,
		Etag:       etag,
	}); err != nil {
		t.Fatal(err)
	}

	collected, err := collectModulePrefixRows(context.Background(), m, srv.Client(), tenant, mod, nil)
	if err != nil {
		t.Fatal(err)
	}
	if gotIfNoneMatch != etag {
		t.Fatalf("want If-None-Match %q, got %q", etag, gotIfNoneMatch)
	}
	if len(collected) != 1 || collected[0].Prefix != "198.51.100.0/24" {
		t.Fatalf("unexpected collected rows: %+v", collected)
	}
}

func TestCollectModulePrefixRows_CDN304UsesSnapshot(t *testing.T) {
	t.Setenv("EVOBGP_CDN_ALLOW_PRIVATE", "1")
	m := store.NewMemory()
	m.SeedDemo()
	tenant, _, _, _, _ := m.DemoIDs()

	mod, err := m.CreateModule(tenant, &store.Module{
		Type:    "CDN_CIDRS",
		Name:    "cdn-304",
		Enabled: true,
	})
	if err != nil {
		t.Fatal(err)
	}

	srv := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusNotModified)
	}))
	defer srv.Close()

	etag := "etag-stable"
	src, err := m.CreateCDNSource(tenant, mod.ID, &store.CDNSource{
		SourceKind: "txt",
		URL:        srv.URL,
		Etag:       etag,
	})
	if err != nil {
		t.Fatal(err)
	}
	prior := []store.PrefixRow{{
		Prefix: "203.0.113.0/24",
		Source: cdnSourceKey(src.ID),
	}}
	if err := mergeCDNSourceIntoModuleSnapshot(m, tenant, mod, src.ID, prior); err != nil {
		t.Fatal(err)
	}

	collected, err := collectModulePrefixRows(context.Background(), m, srv.Client(), tenant, mod, prior)
	if err != nil {
		t.Fatal(err)
	}
	if len(collected) != 1 || collected[0].Prefix != "203.0.113.0/24" {
		t.Fatalf("want cached prefix on 304, got %+v", collected)
	}
}

func TestRefreshModuleIngest_CDN304UsesStoredSnapshot(t *testing.T) {
	t.Setenv("EVOBGP_CDN_ALLOW_PRIVATE", "1")
	m := store.NewMemory()
	m.SeedDemo()
	tenant, _, _, _, _ := m.DemoIDs()

	mod, err := m.CreateModule(tenant, &store.Module{
		Type:    "CDN_CIDRS",
		Name:    "cdn-304-ingest",
		Enabled: true,
	})
	if err != nil {
		t.Fatal(err)
	}

	srv := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusNotModified)
	}))
	defer srv.Close()

	etag := "etag-stable"
	src, err := m.CreateCDNSource(tenant, mod.ID, &store.CDNSource{
		SourceKind: "txt",
		URL:        srv.URL,
		Etag:       etag,
	})
	if err != nil {
		t.Fatal(err)
	}
	prior := []store.PrefixRow{{
		Prefix: "203.0.113.0/24",
		Source: cdnSourceKey(src.ID),
	}}
	if err := mergeCDNSourceIntoModuleSnapshot(m, tenant, mod, src.ID, prior); err != nil {
		t.Fatal(err)
	}

	if err := RefreshModuleIngest(context.Background(), m, srv.Client(), tenant, mod.ID); err != nil {
		t.Fatal(err)
	}
}

func TestCollectModulePrefixRows_CDN304RetriesWithoutETag(t *testing.T) {
	t.Setenv("EVOBGP_CDN_ALLOW_PRIVATE", "1")
	m := store.NewMemory()
	m.SeedDemo()
	tenant, _, _, _, _ := m.DemoIDs()

	mod, err := m.CreateModule(tenant, &store.Module{
		Type:    "CDN_CIDRS",
		Name:    "cdn-304-retry",
		Enabled: true,
	})
	if err != nil {
		t.Fatal(err)
	}

	var calls int
	srv := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		calls++
		if calls == 1 {
			if got := strings.TrimSpace(r.Header.Get("If-None-Match")); got != "etag-stable" {
				t.Fatalf("first request want If-None-Match etag-stable, got %q", got)
			}
			w.WriteHeader(http.StatusNotModified)
			return
		}
		if got := strings.TrimSpace(r.Header.Get("If-None-Match")); got != "" {
			t.Fatalf("retry must omit If-None-Match, got %q", got)
		}
		w.Header().Set("ETag", "etag-stable")
		_, _ = w.Write([]byte("198.51.100.0/24\n"))
	}))
	defer srv.Close()

	if _, err := m.CreateCDNSource(tenant, mod.ID, &store.CDNSource{
		SourceKind: "txt",
		URL:        srv.URL,
		Etag:       "etag-stable",
	}); err != nil {
		t.Fatal(err)
	}

	collected, err := collectModulePrefixRows(context.Background(), m, srv.Client(), tenant, mod, nil)
	if err != nil {
		t.Fatal(err)
	}
	if calls != 2 {
		t.Fatalf("want 2 HTTP calls (304 then 200), got %d", calls)
	}
	if len(collected) != 1 || collected[0].Prefix != "198.51.100.0/24" {
		t.Fatalf("unexpected collected rows: %+v", collected)
	}
}

func TestPrefetchCDNSourceETags_SkipsFreshSources(t *testing.T) {
	t.Setenv("EVOBGP_CDN_ALLOW_PRIVATE", "1")
	m := store.NewMemory()
	m.SeedDemo()
	tenant, _, _, _, _ := m.DemoIDs()

	mod, err := m.CreateModule(tenant, &store.Module{
		Type:    "CDN_CIDRS",
		Name:    "cdn-prefetch-due",
		Enabled: true,
	})
	if err != nil {
		t.Fatal(err)
	}

	var hits atomic.Int32
	srv := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		hits.Add(1)
		w.Header().Set("ETag", `"v1"`)
		_, _ = w.Write([]byte("198.51.100.0/24\n"))
	}))
	defer srv.Close()

	// Fresh source: refreshed 30s ago with a 3600s interval — prefetch must skip it.
	freshAt := time.Now().UTC().Add(-30 * time.Second)
	interval := 3600
	if _, err := m.CreateCDNSource(tenant, mod.ID, &store.CDNSource{
		SourceKind:         "txt",
		URL:                srv.URL,
		RefreshIntervalSec: &interval,
		LastRefreshedAt:    &freshAt,
	}); err != nil {
		t.Fatal(err)
	}

	if err := PrefetchCDNSourceETags(context.Background(), m, srv.Client()); err != nil {
		t.Fatal(err)
	}
	if hits.Load() != 0 {
		t.Fatalf("fresh source must be skipped by prefetch, got %d HTTP hits", hits.Load())
	}

	// Stale source: last refresh older than its interval — prefetch must probe it.
	staleAt := time.Now().UTC().Add(-7200 * time.Second)
	if _, err := m.CreateCDNSource(tenant, mod.ID, &store.CDNSource{
		SourceKind:         "txt",
		URL:                srv.URL + "?stale",
		RefreshIntervalSec: &interval,
		LastRefreshedAt:    &staleAt,
	}); err != nil {
		t.Fatal(err)
	}
	if err := PrefetchCDNSourceETags(context.Background(), m, srv.Client()); err != nil {
		t.Fatal(err)
	}
	if hits.Load() == 0 {
		t.Fatal("stale source must be probed by prefetch")
	}
}