package handlers

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

	"veza-backend-api/internal/config"

	"github.com/gin-gonic/gin"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func newWebRTCRouter(cfg *config.Config) *gin.Engine {
	gin.SetMode(gin.TestMode)
	r := gin.New()
	r.GET("/config/webrtc", GetWebRTCConfig(cfg))
	return r
}

func decodeWebRTC(t *testing.T, w *httptest.ResponseRecorder) WebRTCConfigResponse {
	t.Helper()
	var resp WebRTCConfigResponse
	require.NoError(t, json.NewDecoder(w.Body).Decode(&resp))
	return resp
}

func TestGetWebRTCConfig_StunOnlyWhenNoTurn(t *testing.T) {
	cfg := &config.Config{
		WebRTCStunURLs: []string{"stun:stun.example.org:3478"},
	}
	r := newWebRTCRouter(cfg)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/config/webrtc", nil)
	r.ServeHTTP(w, req)

	require.Equal(t, http.StatusOK, w.Code)
	resp := decodeWebRTC(t, w)
	require.Len(t, resp.IceServers, 1)
	assert.Equal(t, []string{"stun:stun.example.org:3478"}, resp.IceServers[0].URLs)
	assert.Empty(t, resp.IceServers[0].Username)
	assert.Empty(t, resp.IceServers[0].Credential)
}

func TestGetWebRTCConfig_EmitsTurnBlockWhenFullyConfigured(t *testing.T) {
	cfg := &config.Config{
		WebRTCStunURLs:       []string{"stun:stun.example.org:3478"},
		WebRTCTurnURLs:       []string{"turn:turn.veza.local:3478", "turns:turn.veza.local:5349"},
		WebRTCTurnUsername:   "vezauser",
		WebRTCTurnCredential: "shhhhh",
	}
	r := newWebRTCRouter(cfg)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/config/webrtc", nil)
	r.ServeHTTP(w, req)

	require.Equal(t, http.StatusOK, w.Code)
	resp := decodeWebRTC(t, w)
	require.Len(t, resp.IceServers, 2)

	assert.Equal(t, []string{"stun:stun.example.org:3478"}, resp.IceServers[0].URLs)
	assert.Equal(t, []string{"turn:turn.veza.local:3478", "turns:turn.veza.local:5349"}, resp.IceServers[1].URLs)
	assert.Equal(t, "vezauser", resp.IceServers[1].Username)
	assert.Equal(t, "shhhhh", resp.IceServers[1].Credential)
}

func TestGetWebRTCConfig_OmitsTurnBlockWhenHalfConfigured(t *testing.T) {
	// Half-configured TURN (URLs but no creds) is worse than missing —
	// the browser would surface auth failures instead of falling back
	// cleanly. The handler omits the block in that case.
	cases := map[string]*config.Config{
		"missing username": {
			WebRTCStunURLs:       []string{"stun:s.test:3478"},
			WebRTCTurnURLs:       []string{"turn:t.test:3478"},
			WebRTCTurnCredential: "creds",
		},
		"missing credential": {
			WebRTCStunURLs:     []string{"stun:s.test:3478"},
			WebRTCTurnURLs:     []string{"turn:t.test:3478"},
			WebRTCTurnUsername: "user",
		},
		"missing urls": {
			WebRTCStunURLs:       []string{"stun:s.test:3478"},
			WebRTCTurnUsername:   "user",
			WebRTCTurnCredential: "creds",
		},
	}
	for name, cfg := range cases {
		t.Run(name, func(t *testing.T) {
			r := newWebRTCRouter(cfg)
			w := httptest.NewRecorder()
			req := httptest.NewRequest(http.MethodGet, "/config/webrtc", nil)
			r.ServeHTTP(w, req)

			require.Equal(t, http.StatusOK, w.Code)
			resp := decodeWebRTC(t, w)
			assert.Len(t, resp.IceServers, 1, "only the STUN entry should be present when TURN is partial")
			assert.Equal(t, []string{"stun:s.test:3478"}, resp.IceServers[0].URLs)
		})
	}
}

func TestGetWebRTCConfig_EmptyConfigReturnsEmptyIceServers(t *testing.T) {
	cfg := &config.Config{} // no STUN, no TURN
	r := newWebRTCRouter(cfg)
	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/config/webrtc", nil)
	r.ServeHTTP(w, req)

	require.Equal(t, http.StatusOK, w.Code)
	resp := decodeWebRTC(t, w)
	assert.Empty(t, resp.IceServers)
}