package upstreamimpl

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

	"git.5iot.com/iotlcm-public/iotlcm-upstream-chan/internal/model"
	"git.5iot.com/iotlcm-public/iotlcm-upstream-chan/internal/model/entity"
)

func TestTibiotRateLimiterSpacesRequestsAndHonorsCancellation(t *testing.T) {
	limiter := newTibiotRateLimiter(25 * time.Millisecond)
	if err := limiter.wait(context.Background()); err != nil {
		t.Fatalf("first wait failed: %v", err)
	}

	started := time.Now()
	if err := limiter.wait(context.Background()); err != nil {
		t.Fatalf("second wait failed: %v", err)
	}
	if elapsed := time.Since(started); elapsed < 20*time.Millisecond {
		t.Fatalf("second slot was granted too early: %s", elapsed)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Millisecond)
	defer cancel()
	reservedBeforeCancel := limiter.next
	if err := limiter.wait(ctx); err == nil {
		t.Fatal("expected cancellation while waiting for a slot")
	}
	if !limiter.next.Equal(reservedBeforeCancel) {
		t.Fatalf("canceled waiter reserved a slot: before=%s after=%s", reservedBeforeCancel, limiter.next)
	}
}

func TestTibiotQuerySimDataUsageRetriesOnceAfterUpstreamFailure(t *testing.T) {
	previousLimiter := tibiotSimDataMarginLimiter
	tibiotSimDataMarginLimiter = newTibiotRateLimiter(time.Millisecond)
	defer func() { tibiotSimDataMarginLimiter = previousLimiter }()

	var calls atomic.Int32
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		var body map[string]any
		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
			t.Fatalf("decode request: %v", err)
		}
		if body["flowUnit"] != "MB" {
			t.Fatalf("flowUnit missing: %#v", body)
		}
		if calls.Add(1) == 1 {
			_, _ = w.Write([]byte(`{"status":10049,"message":"too many requests","data":null}`))
			return
		}
		_, _ = w.Write([]byte(`{"status":0,"message":"ok","data":"2MB"}`))
	}))
	defer server.Close()

	client := NewSimTibiot().NewTemp(context.Background(), &model.SimChannelConfigItemCache{
		Template: &entity.TSimChannelTemplate{
			TempConfig: `{"api":{"baseUrl":"` + server.URL + `"},"http":{"timeout":"2s"}}`,
		},
		Channel: &entity.TSimChannels{ChanConfig: `{"userName":"tester","password":"secret"}`},
	}).(*sSimTibiot)
	items, err := client.QuerySimDataUsage(context.Background(), &model.SimDataUsageInput{
		SimKeys: []*model.SimKey{{ICCID: "8986000000000000000"}},
	})
	if err != nil || len(items) != 1 {
		t.Fatalf("unexpected query result: items=%#v err=%v", items, err)
	}
	if calls.Load() != 2 {
		t.Fatalf("upstream calls = %d, want one retry", calls.Load())
	}
	if items[0].Code != 0 || items[0].ResData.DataUsage != 2 {
		t.Fatalf("unexpected successful retry result: %#v", items[0])
	}

	cachedItems, err := client.QuerySimDataUsage(context.Background(), &model.SimDataUsageInput{
		SimKeys: []*model.SimKey{{ICCID: "8986000000000000000"}},
	})
	if err != nil || len(cachedItems) != 1 {
		t.Fatalf("unexpected cached query result: items=%#v err=%v", cachedItems, err)
	}
	if calls.Load() != 2 {
		t.Fatalf("cached query called upstream again: calls=%d", calls.Load())
	}
	if !cachedItems[0].Cached || cachedItems[0].UpdatedAt == "" {
		t.Fatalf("cached query metadata missing: %#v", cachedItems[0])
	}
}