package response

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

	"github.com/gin-gonic/gin"
)

func init() { gin.SetMode(gin.TestMode) }

func run(handler gin.HandlerFunc) *httptest.ResponseRecorder {
	r := gin.New()
	r.GET("/x", handler)
	rec := httptest.NewRecorder()
	req, _ := http.NewRequest(http.MethodGet, "/x", nil)
	r.ServeHTTP(rec, req)
	return rec
}

func decodeEnv(t *testing.T, rec *httptest.ResponseRecorder) Envelope {
	t.Helper()
	var env Envelope
	if err := json.Unmarshal(rec.Body.Bytes(), &env); err != nil {
		t.Fatalf("decode: %v (body=%s)", err, rec.Body.String())
	}
	return env
}

func TestOK_Wraps200AndMessage(t *testing.T) {
	rec := run(func(c *gin.Context) { OK(c, map[string]int{"n": 7}) })
	if rec.Code != http.StatusOK {
		t.Fatalf("status: %d", rec.Code)
	}
	env := decodeEnv(t, rec)
	if env.Error != nil {
		t.Errorf("error should be nil, got %q", *env.Error)
	}
	if env.Message != "OK" {
		t.Errorf("message: %q", env.Message)
	}
}

func TestErr_SerialisesErrorAndMessage(t *testing.T) {
	rec := run(func(c *gin.Context) { Err(c, http.StatusBadRequest, errors.New("boom")) })
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status: %d", rec.Code)
	}
	env := decodeEnv(t, rec)
	if env.Error == nil || *env.Error != "boom" {
		t.Errorf("error: %v", env.Error)
	}
	if env.Message != "boom" {
		t.Errorf("message: %q", env.Message)
	}
	if env.Data != nil {
		t.Errorf("data should be nil on error, got %v", env.Data)
	}
}

func TestNoContent_NoBody(t *testing.T) {
	rec := run(func(c *gin.Context) { NoContent(c) })
	if rec.Code != http.StatusNoContent {
		t.Fatalf("status: %d", rec.Code)
	}
	if rec.Body.Len() != 0 {
		t.Errorf("204 should have empty body, got %q", rec.Body.String())
	}
}