package fizzbuzz

import (
	"encoding/json"
	"io/ioutil"
	"net/http"
	"net/http/httptest"
	"reflect"
	"strings"
	"testing"
)

func TestServer(t *testing.T) {
	restAPI := &Server{}
	tserver := httptest.NewServer(restAPI.Routes())
	defer tserver.Close()

	t.Run("invalid URLs", func(t *testing.T) {
		tcases := []struct {
			urlParams   string
			errCode     int
			errContains string
		}{
			{urlParams: "?limit=toto", errCode: 400, errContains: "invalid integer 'toto'"},
			{urlParams: "?int1=tata", errCode: 400, errContains: "int1"},
			{urlParams: "?int2=titi", errCode: 400, errContains: "int2"},
			{urlParams: "/notFoundPath", errCode: 404, errContains: "not found"},
		}
		for i, tcase := range tcases {
			resp, err := http.Get(tserver.URL + tcase.urlParams)
			if err != nil {
				t.Fatalf("%d: %s", i+1, err)
			}
			assertStatus(i, t, resp, tcase.errCode)
			if got, want := readErrorFromResponse(t, resp), tcase.errContains; !strings.Contains(got, want) {
				t.Fatalf("%d: expect errors contains %s, got %s", i+1, want, got)
			}
		}
	})
	t.Run("valid URLs", func(t *testing.T) {
		emptyList := []string{}
		tcases := []struct {
			urlParams string
			expectOut []string
		}{
			// Invalid cases
			{urlParams: "", expectOut: emptyList},
			{urlParams: "?", expectOut: emptyList},
			{urlParams: "?limit=0", expectOut: emptyList},
			{urlParams: "?string1=aa&string2=bb&int1=2&int2=3&limit=0", expectOut: emptyList},
			// Valid case
			{
				urlParams: "?string1=aa&string2=bb&int1=3&int2=2&limit=12",
				expectOut: []string{"1", "bb", "aa", "bb", "5", "aabb", "7", "bb", "aa", "bb", "11", "aabb"},
			},
		}
		for i, tcase := range tcases {
			resp, err := http.Get(tserver.URL + tcase.urlParams)
			if err != nil {
				t.Fatalf("%d: %s", i+1, err)
			}
			assertStatus(i, t, resp, 200)
			if got, want := readListFromResponse(t, resp), tcase.expectOut; !reflect.DeepEqual(got, want) {
				t.Fatalf("%d: got %#v, want %#v", i+1, got, want)
			}
		}
	})

}

func assertStatus(i int, t *testing.T, resp *http.Response, expect int) {
	t.Helper()
	if got, want := resp.StatusCode, expect; got != want {
		t.Fatalf("%d, got %d, want %d", i+1, got, want)
	}
}

func readListFromResponse(t *testing.T, resp *http.Response) []string {
	t.Helper()
	defer resp.Body.Close()
	var list []string
	bytes, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		t.Fatal(err)
	}
	if len(bytes) == 0 {
		return list
	}
	if err = json.Unmarshal(bytes, &list); err != nil {
		t.Fatalf("error while unmarshalling %s: %s", string(bytes), err)
	}
	return list
}

func readErrorFromResponse(t *testing.T, resp *http.Response) string {
	t.Helper()
	defer resp.Body.Close()
	bytes, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		t.Fatal(err)
	}
	return string(bytes)
}