package main

import (
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

// A load generator must never report a fast failure page as good throughput.
func TestExchangeRejectsInvalidResponses(t *testing.T) {
	for _, tt := range []struct {
		name      string
		status    int
		body      string
		requestID string
		truncated bool
		wantOK    bool
	}{
		{"valid", 200, expectedBody, "perfCheck", false, true},
		{"overload", 503, "server busy", "perfCheck", false, false},
		{"wrongPayload", 200, `{"data":"wrong"}`, "perfCheck", false, false},
		{"missingRequestId", 200, expectedBody, "", false, false},
		{"truncated", 200, expectedBody, "perfCheck", true, false},
	} {
		t.Run(tt.name, func(t *testing.T) {
			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				if r.Header.Get("X-Request-ID") != "perfCheck" {
					t.Error("client did not send fixed requestId")
				}
				w.Header().Set("X-Request-ID", tt.requestID)
				if tt.truncated {
					w.Header().Set("Content-Length", "4096")
				}
				w.WriteHeader(tt.status)
				_, _ = w.Write([]byte(tt.body))
			}))
			defer server.Close()
			err := exchange(server.Client(), strings.TrimPrefix(server.URL, "http://"))
			if (err == nil) != tt.wantOK {
				t.Fatalf("valid=%v, error=%v", tt.wantOK, err)
			}
		})
	}
}

func TestExchangeModeTLS(t *testing.T) {
	server := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("X-Request-ID", "perfCheck")
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte(expectedBody))
	}))
	defer server.Close()
	if err := exchangeMode(server.Client(), strings.TrimPrefix(server.URL, "https://"), true); err != nil {
		t.Fatal(err)
	}
}

func TestPercentileBounds(t *testing.T) {
	var h histogram
	// Known ranks, including a tail much slower than the median.
	for i := 1; i <= 100; i++ {
		h.add(time.Duration(i) * time.Millisecond)
	}
	for _, p := range []uint64{50, 95, 99} {
		value := h.percentile(100, p)
		if value < float64(p) || value > float64(p)*1.0625 {
			t.Fatalf("p%d=%gms outside advertised bucket rounding", p, value)
		}
	}
	if value := h.percentile(0, 95); value != 0 {
		t.Fatalf("empty histogram returned %g", value)
	}
}