package engineclient

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"galaxy/model/rest"

	"github.com/google/uuid"
)

func newTestClient(t *testing.T, srv *httptest.Server) *Client {
	t.Helper()
	cli, err := NewClientWithHTTP(Config{CallTimeout: 2 * time.Second, ProbeTimeout: 1 * time.Second}, srv.Client())
	if err != nil {
		t.Fatalf("NewClientWithHTTP: %v", err)
	}
	return cli
}

func TestClientInitSuccess(t *testing.T) {
	wantID := uuid.New()
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != pathAdminInit {
			t.Fatalf("unexpected path: %s", r.URL.Path)
		}
		if r.Method != http.MethodPost {
			t.Fatalf("unexpected method: %s", r.Method)
		}
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(rest.StateResponse{ID: wantID, Turn: 1, Players: []rest.PlayerState{{ID: uuid.New(), RaceName: "alpha"}}})
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	got, err := cli.Init(context.Background(), srv.URL, rest.InitRequest{Races: []rest.InitRace{{RaceName: "alpha"}}})
	if err != nil {
		t.Fatalf("Init returned error: %v", err)
	}
	if got.ID != wantID {
		t.Fatalf("ID = %s, want %s", got.ID, wantID)
	}
	if got.Turn != 1 {
		t.Fatalf("Turn = %d, want 1", got.Turn)
	}
}

func TestClientInitValidationError(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, `{"reason":"races empty"}`, http.StatusBadRequest)
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	_, err := cli.Init(context.Background(), srv.URL, rest.InitRequest{Races: []rest.InitRace{{RaceName: "x"}}})
	if !errors.Is(err, ErrEngineValidation) {
		t.Fatalf("expected ErrEngineValidation, got %v", err)
	}
}

func TestClientInitUnreachableOn5xx(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "boom", http.StatusInternalServerError)
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	_, err := cli.Init(context.Background(), srv.URL, rest.InitRequest{Races: []rest.InitRace{{RaceName: "x"}}})
	if !errors.Is(err, ErrEngineUnreachable) {
		t.Fatalf("expected ErrEngineUnreachable, got %v", err)
	}
}

func TestClientInitProtocolViolation(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte("not-json"))
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	_, err := cli.Init(context.Background(), srv.URL, rest.InitRequest{Races: []rest.InitRace{{RaceName: "x"}}})
	if !errors.Is(err, ErrEngineProtocolViolation) {
		t.Fatalf("expected ErrEngineProtocolViolation, got %v", err)
	}
}

func TestClientStatusOK(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != pathAdminStatus || r.Method != http.MethodGet {
			t.Fatalf("unexpected request: %s %s", r.Method, r.URL.Path)
		}
		_ = json.NewEncoder(w).Encode(rest.StateResponse{Turn: 5})
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	got, err := cli.Status(context.Background(), srv.URL)
	if err != nil {
		t.Fatalf("Status: %v", err)
	}
	if got.Turn != 5 {
		t.Fatalf("Turn = %d, want 5", got.Turn)
	}
}

func TestClientTurnOK(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != pathAdminTurn || r.Method != http.MethodPut {
			t.Fatalf("unexpected request: %s %s", r.Method, r.URL.Path)
		}
		_ = json.NewEncoder(w).Encode(rest.StateResponse{Turn: 6, Finished: true})
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	got, err := cli.Turn(context.Background(), srv.URL)
	if err != nil {
		t.Fatalf("Turn: %v", err)
	}
	if !got.Finished {
		t.Fatalf("expected finished=true")
	}
}

func TestClientBanishRace(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != pathAdminRaceBanish || r.Method != http.MethodPost {
			t.Fatalf("unexpected request: %s %s", r.Method, r.URL.Path)
		}
		var got rest.BanishRequest
		_ = json.NewDecoder(r.Body).Decode(&got)
		if got.RaceName != "loser" {
			t.Fatalf("got race name %q", got.RaceName)
		}
		w.WriteHeader(http.StatusNoContent)
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	if err := cli.BanishRace(context.Background(), srv.URL, "loser"); err != nil {
		t.Fatalf("BanishRace: %v", err)
	}
}

func TestClientCommandsForwardsBody(t *testing.T) {
	want := json.RawMessage(`{"actor":"alpha","cmd":[{"@type":"raceQuit"}]}`)
	gotResp := json.RawMessage(`{"applied":true}`)
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != pathPlayerCommand || r.Method != http.MethodPut {
			t.Fatalf("unexpected request: %s %s", r.Method, r.URL.Path)
		}
		_, _ = w.Write(gotResp)
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	resp, err := cli.ExecuteCommands(context.Background(), srv.URL, want)
	if err != nil {
		t.Fatalf("ExecuteCommands: %v", err)
	}
	if string(resp) != string(gotResp) {
		t.Fatalf("response = %s, want %s", string(resp), string(gotResp))
	}
}

func TestClientReportsForwardsQuery(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != pathPlayerReport {
			t.Fatalf("unexpected path: %s", r.URL.Path)
		}
		if r.URL.Query().Get("player") != "alpha" {
			t.Fatalf("player = %q", r.URL.Query().Get("player"))
		}
		if r.URL.Query().Get("turn") != "3" {
			t.Fatalf("turn = %q", r.URL.Query().Get("turn"))
		}
		_, _ = w.Write([]byte(`{"turn":3}`))
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	body, err := cli.GetReport(context.Background(), srv.URL, "alpha", 3)
	if err != nil {
		t.Fatalf("GetReport: %v", err)
	}
	if !strings.Contains(string(body), `"turn":3`) {
		t.Fatalf("body = %s", body)
	}
}

func TestClientGetOrderForwardsQuery(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != pathPlayerOrder {
			t.Fatalf("unexpected path: %s", r.URL.Path)
		}
		if r.Method != http.MethodGet {
			t.Fatalf("unexpected method: %s", r.Method)
		}
		if r.URL.Query().Get("player") != "alpha" {
			t.Fatalf("player = %q", r.URL.Query().Get("player"))
		}
		if r.URL.Query().Get("turn") != "3" {
			t.Fatalf("turn = %q", r.URL.Query().Get("turn"))
		}
		_, _ = w.Write([]byte(`{"game_id":"abc","updatedAt":99,"cmd":[]}`))
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	body, status, err := cli.GetOrder(context.Background(), srv.URL, "alpha", 3)
	if err != nil {
		t.Fatalf("GetOrder: %v", err)
	}
	if status != http.StatusOK {
		t.Fatalf("status = %d", status)
	}
	if !strings.Contains(string(body), `"updatedAt":99`) {
		t.Fatalf("body = %s", body)
	}
}

func TestClientGetOrderNoContent(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusNoContent)
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	body, status, err := cli.GetOrder(context.Background(), srv.URL, "alpha", 3)
	if err != nil {
		t.Fatalf("GetOrder: %v", err)
	}
	if status != http.StatusNoContent {
		t.Fatalf("status = %d", status)
	}
	if body != nil {
		t.Fatalf("expected nil body on 204, got %s", body)
	}
}

func TestClientGetOrderRejectsBadInput(t *testing.T) {
	cli := newTestClient(t, httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		t.Fatal("server must not be hit on bad input")
	})))
	if _, _, err := cli.GetOrder(context.Background(), "http://example.com", "", 0); err == nil {
		t.Fatal("expected error on empty race name")
	}
	if _, _, err := cli.GetOrder(context.Background(), "http://example.com", "alpha", -1); err == nil {
		t.Fatal("expected error on negative turn")
	}
}

func TestClientFetchBattleForwardsPath(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodGet {
			t.Fatalf("unexpected method: %s", r.Method)
		}
		want := pathPlayerBattle + "/3/" + "11111111-1111-1111-1111-111111111111"
		if r.URL.Path != want {
			t.Fatalf("path = %q, want %q", r.URL.Path, want)
		}
		_, _ = w.Write([]byte(`{"id":"11111111-1111-1111-1111-111111111111","planet":4}`))
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	body, status, err := cli.FetchBattle(context.Background(), srv.URL, 3, "11111111-1111-1111-1111-111111111111")
	if err != nil {
		t.Fatalf("FetchBattle: %v", err)
	}
	if status != http.StatusOK {
		t.Fatalf("status = %d", status)
	}
	if !strings.Contains(string(body), `"planet":4`) {
		t.Fatalf("body = %s", body)
	}
}

func TestClientFetchBattleNotFound(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusNotFound)
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	body, status, err := cli.FetchBattle(context.Background(), srv.URL, 0, "11111111-1111-1111-1111-111111111111")
	if err != nil {
		t.Fatalf("FetchBattle: %v", err)
	}
	if status != http.StatusNotFound {
		t.Fatalf("status = %d", status)
	}
	if body != nil {
		t.Fatalf("expected nil body on 404, got %s", body)
	}
}

func TestClientFetchBattleRejectsBadInput(t *testing.T) {
	cli := newTestClient(t, httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		t.Fatal("server must not be hit on bad input")
	})))
	if _, _, err := cli.FetchBattle(context.Background(), "http://example.com", -1, "11111111-1111-1111-1111-111111111111"); err == nil {
		t.Fatal("expected error on negative turn")
	}
	if _, _, err := cli.FetchBattle(context.Background(), "http://example.com", 0, ""); err == nil {
		t.Fatal("expected error on empty battle id")
	}
}

func TestClientHealthzSuccess(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != pathHealthz {
			t.Fatalf("unexpected path: %s", r.URL.Path)
		}
		_, _ = w.Write([]byte(`{"status":"ok"}`))
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	if err := cli.Healthz(context.Background(), srv.URL); err != nil {
		t.Fatalf("Healthz: %v", err)
	}
}

func TestClientHealthzFailure(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "down", http.StatusServiceUnavailable)
	}))
	t.Cleanup(srv.Close)

	cli := newTestClient(t, srv)
	if err := cli.Healthz(context.Background(), srv.URL); !errors.Is(err, ErrEngineUnreachable) {
		t.Fatalf("expected ErrEngineUnreachable, got %v", err)
	}
}

func TestClientRejectsInvalidBaseURL(t *testing.T) {
	cli, err := NewClientWithHTTP(Config{CallTimeout: time.Second, ProbeTimeout: time.Second}, http.DefaultClient)
	if err != nil {
		t.Fatalf("NewClientWithHTTP: %v", err)
	}
	if _, err := cli.Status(context.Background(), ""); err == nil {
		t.Fatalf("expected error on empty base URL")
	}
	if _, err := cli.Status(context.Background(), "ftp://example.test"); err == nil {
		t.Fatalf("expected error on non-http base URL")
	}
}
