package health

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"testing"
)

func TestHealthzAlwaysOK(t *testing.T) {
	h := New()
	rr := httptest.NewRecorder()
	h.Healthz(rr, httptest.NewRequestWithContext(t.Context(), "GET", "/healthz", http.NoBody))

	if rr.Code != 200 {
		t.Errorf("status = %d", rr.Code)
	}
	if rr.Body.String() != "ok" {
		t.Errorf("body = %q", rr.Body.String())
	}
}

func TestReadyzNoCheckersIsOK(t *testing.T) {
	h := New()
	rr := httptest.NewRecorder()
	h.Readyz(rr, httptest.NewRequestWithContext(t.Context(), "GET", "/readyz", http.NoBody))

	if rr.Code != 200 {
		t.Errorf("status = %d", rr.Code)
	}

	var body map[string]string
	if err := json.Unmarshal(rr.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if len(body) != 0 {
		t.Errorf("expected empty results, got %v", body)
	}
}

func TestReadyzAllPass(t *testing.T) {
	h := New()
	h.Register("db", CheckerFunc(func(_ context.Context) error { return nil }))
	h.Register("cache", CheckerFunc(func(_ context.Context) error { return nil }))

	rr := httptest.NewRecorder()
	h.Readyz(rr, httptest.NewRequestWithContext(t.Context(), "GET", "/readyz", http.NoBody))

	if rr.Code != 200 {
		t.Errorf("status = %d", rr.Code)
	}
	var body map[string]string
	if err := json.Unmarshal(rr.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if body["db"] != "ok" || body["cache"] != "ok" {
		t.Errorf("body = %v", body)
	}
}

func TestReadyzOneFails(t *testing.T) {
	h := New()
	h.Register("db", CheckerFunc(func(_ context.Context) error { return nil }))
	h.Register("upstream", CheckerFunc(func(_ context.Context) error { return errors.New("dns fail") }))

	rr := httptest.NewRecorder()
	h.Readyz(rr, httptest.NewRequestWithContext(t.Context(), "GET", "/readyz", http.NoBody))

	if rr.Code != 503 {
		t.Errorf("status = %d, want 503", rr.Code)
	}
	var body map[string]string
	if err := json.Unmarshal(rr.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if body["db"] != "ok" {
		t.Errorf("db = %q", body["db"])
	}
	if body["upstream"] != "dns fail" {
		t.Errorf("upstream = %q", body["upstream"])
	}
}

func TestRegisterReplaces(t *testing.T) {
	h := New()
	h.Register("svc", CheckerFunc(func(_ context.Context) error { return errors.New("first") }))
	h.Register("svc", CheckerFunc(func(_ context.Context) error { return nil }))

	rr := httptest.NewRecorder()
	h.Readyz(rr, httptest.NewRequestWithContext(t.Context(), "GET", "/readyz", http.NoBody))
	if rr.Code != 200 {
		t.Errorf("status = %d, want 200 after replace", rr.Code)
	}
}