package openstack

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

	"github.com/gophercloud/gophercloud/v2"
)

// TestClientListFreeFloatingIPsAgainstFakeNeutron drives the real Client
// against an httptest server: marker pagination, the `fields` projection, a
// transient 503 that is retried and an empty port_id meaning "free".
func TestClientListFreeFloatingIPsAgainstFakeNeutron(t *testing.T) {
	const total = 5
	var requests int
	failedOnce := false
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requests++
		q := r.URL.Query()
		if got := q["fields"]; len(got) != 4 {
			t.Errorf("expected 4 fields params, got %v", got)
		}
		if q.Get("limit") != "2" {
			t.Errorf("expected limit=2, got %q", q.Get("limit"))
		}
		if q.Get("marker") == "id-1" && !failedOnce {
			failedOnce = true
			http.Error(w, "busy", http.StatusServiceUnavailable)
			return
		}
		start := 0
		if m := q.Get("marker"); m != "" {
			fmt.Sscanf(m, "id-%d", &start)
			start++
		}
		type fip struct {
			ID       string  `json:"id"`
			Addr     string  `json:"floating_ip_address"`
			PortID   *string `json:"port_id"`
			TenantID string  `json:"tenant_id"`
		}
		var items []fip
		for i := start; i < total && len(items) < 2; i++ {
			f := fip{ID: fmt.Sprintf("id-%d", i), Addr: fmt.Sprintf("203.0.113.%d", i+1), TenantID: "p"}
			if i == 1 {
				p := "port-1"
				f.PortID = &p
			}
			items = append(items, f)
		}
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(map[string]any{"floatingips": items})
	}))
	defer srv.Close()

	c := &Client{
		networking: &gophercloud.ServiceClient{
			ProviderClient: &gophercloud.ProviderClient{HTTPClient: *srv.Client()},
			Endpoint:       srv.URL + "/",
			ResourceBase:   srv.URL + "/v2.0/",
		},
		retry: pageRetry{Retries: 3, Sleep: func(context.Context, time.Duration) error { return nil }},
	}
	var all []FloatingIP
	pages, err := c.ListFreeFloatingIPs(context.Background(), 2, func(p []FloatingIP) error {
		all = append(all, p...)
		return nil
	})
	if err != nil {
		t.Fatalf("list: %v", err)
	}
	if pages != 3 || len(all) != total {
		t.Fatalf("expected 3 pages / 5 fips, got %d / %d", pages, len(all))
	}
	if all[1].PortID != "port-1" || all[0].PortID != "" || all[4].Address != "203.0.113.5" {
		t.Fatalf("unexpected mapping: %+v", all)
	}
	if requests != 4 { // 3 pages + 1 retried 503
		t.Fatalf("expected 4 requests, got %d", requests)
	}
}