package server

import (
	"bytes"
	"encoding/json"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"path/filepath"
	"testing"

	"github.com/wzray/dns/internal/resolv"
)

func newTestServer(t *testing.T) (*Server, string) {
	t.Helper()
	path := filepath.Join(t.TempDir(), "resolv.conf")
	mgr := resolv.New(path)
	log := slog.New(slog.NewTextHandler(io.Discard, nil))
	return New(mgr, log), path
}

func do(t *testing.T, h http.Handler, method, target string, body any) *httptest.ResponseRecorder {
	t.Helper()
	var rdr io.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			t.Fatalf("marshal: %v", err)
		}
		rdr = bytes.NewReader(b)
	}
	req := httptest.NewRequest(method, target, rdr)
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	return rec
}

func TestServer_AddListRemove(t *testing.T) {
	s, _ := newTestServer(t)
	h := s.Handler()

	rec := do(t, h, "GET", "/dns", nil)
	if rec.Code != http.StatusOK {
		t.Fatalf("list: status %d", rec.Code)
	}
	var lr listResponse
	if err := json.Unmarshal(rec.Body.Bytes(), &lr); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if len(lr.Servers) != 0 {
		t.Fatalf("want empty, got %v", lr.Servers)
	}

	rec = do(t, h, "POST", "/dns", addRequest{Address: "1.1.1.1"})
	if rec.Code != http.StatusCreated {
		t.Fatalf("add: status %d body %s", rec.Code, rec.Body.String())
	}

	rec = do(t, h, "POST", "/dns", addRequest{Address: "1.1.1.1"})
	if rec.Code != http.StatusConflict {
		t.Fatalf("dup: status %d", rec.Code)
	}

	rec = do(t, h, "POST", "/dns", addRequest{Address: "not-an-ip"})
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("invalid: status %d", rec.Code)
	}

	rec = do(t, h, "DELETE", "/dns/1.1.1.1", nil)
	if rec.Code != http.StatusNoContent {
		t.Fatalf("remove: status %d", rec.Code)
	}

	rec = do(t, h, "DELETE", "/dns/1.1.1.1", nil)
	if rec.Code != http.StatusNotFound {
		t.Fatalf("remove missing: status %d", rec.Code)
	}
}

func TestServer_BadJSON(t *testing.T) {
	s, _ := newTestServer(t)
	h := s.Handler()
	req := httptest.NewRequest("POST", "/dns", bytes.NewReader([]byte("{not json")))
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status %d", rec.Code)
	}
}

func TestServer_HealthAndUnknownRoute(t *testing.T) {
	s, _ := newTestServer(t)
	h := s.Handler()

	if rec := do(t, h, "GET", "/health", nil); rec.Code != http.StatusOK {
		t.Fatalf("health status %d", rec.Code)
	}
	if rec := do(t, h, "GET", "/unknown", nil); rec.Code != http.StatusNotFound {
		t.Fatalf("unknown route status %d", rec.Code)
	}
}