package metrics

import (
	"context"
	"io"
	"net"
	"net/http"
	"net/http/httptest"
	"os"
	"testing"

	"music-server/internal/logging"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestMain(m *testing.M) {
	logging.Init("fatal", false)
	os.Exit(m.Run())
}

func TestServerServesRuntimeMetrics(t *testing.T) {
	rec := httptest.NewRecorder()
	NewServer(0).Handler().ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/metrics", nil))

	assert.Equal(t, http.StatusOK, rec.Code)
	assert.Contains(t, rec.Body.String(), "go_goroutines")
	assert.Contains(t, rec.Body.String(), "process_start_time_seconds")
}

func TestServerServesOnlyMetrics(t *testing.T) {
	rec := httptest.NewRecorder()
	NewServer(0).Handler().ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/", nil))
	assert.Equal(t, http.StatusNotFound, rec.Code)
}

func TestServerStartAndShutdown(t *testing.T) {
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	require.NoError(t, err)
	port := ln.Addr().(*net.TCPAddr).Port
	require.NoError(t, ln.Close())

	s := NewServer(port)
	require.NoError(t, s.Start())
	resp, err := http.Get("http://" + ln.Addr().String() + "/metrics")
	require.NoError(t, err)
	body, _ := io.ReadAll(resp.Body)
	resp.Body.Close()
	assert.Contains(t, string(body), "go_goroutines")

	require.NoError(t, s.Shutdown(context.Background()))
	_, err = http.Get("http://" + ln.Addr().String() + "/metrics")
	assert.Error(t, err, "the port is closed after shutdown")
}

func TestServerStartFailsWhenPortIsTaken(t *testing.T) {
	ln, err := net.Listen("tcp", ":0")
	require.NoError(t, err)
	defer ln.Close()

	assert.Error(t, NewServer(ln.Addr().(*net.TCPAddr).Port).Start())
}