package notification_test

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

	"github.com/nomadcode/nomadcode-core/internal/adapters/mattermost"
	"github.com/nomadcode/nomadcode-core/internal/notification"
)

type recordingSink struct {
	events []notification.TaskEvent
	err    error
}

func (s *recordingSink) HandleTaskEvent(_ context.Context, event notification.TaskEvent) error {
	s.events = append(s.events, event)
	return s.err
}

type logRecord struct {
	msg  string
	args map[string]any
}

type spyHandler struct {
	records []logRecord
}

type mattermostPostBody struct {
	ChannelID string `json:"channel_id"`
	Message   string `json:"message"`
}

func (h *spyHandler) Enabled(ctx context.Context, level slog.Level) bool {
	return true
}

func (h *spyHandler) Handle(ctx context.Context, r slog.Record) error {
	args := make(map[string]any)
	r.Attrs(func(a slog.Attr) bool {
		args[a.Key] = a.Value.Any()
		return true
	})
	h.records = append(h.records, logRecord{
		msg:  r.Message,
		args: args,
	})
	return nil
}

func (h *spyHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
	return h
}

func (h *spyHandler) WithGroup(name string) slog.Handler {
	return h
}

func TestNotifyTaskCompletedUsesTaskEventCompleted(t *testing.T) {
	spy := &spyHandler{}
	logger := slog.New(spy)

	service := notification.NewService(nil, logger)

	err := service.NotifyTaskCompleted(context.Background(), notification.TaskNotification{
		TaskID:  "task-123",
		Title:   "Test Task",
		Status:  "completed",
		Message: "Finished successfully",
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	if len(spy.records) == 0 {
		t.Fatal("expected log records, got none")
	}

	found := false
	for _, rec := range spy.records {
		if rec.msg == "task event notification requested" {
			found = true
			if rec.args["type"] != notification.TaskEventCompleted {
				t.Errorf("expected event type %s, got %v", notification.TaskEventCompleted, rec.args["type"])
			}
			if rec.args["task_id"] != "task-123" {
				t.Errorf("expected task_id task-123, got %v", rec.args["task_id"])
			}
		}
	}
	if !found {
		t.Error("expected 'task event notification requested' log message, not found")
	}
}

func TestNotifyTaskEventFansOutToSinksForRunningAndFailed(t *testing.T) {
	logger := slog.New(&spyHandler{})
	sink := &recordingSink{}
	service := notification.NewService(nil, logger, sink)

	now := time.Now().UTC()
	events := []notification.TaskEvent{
		{
			Type:       notification.TaskEventRunning,
			TaskID:     "task-1",
			Status:     "running",
			Attempt:    1,
			Reason:     "first-try",
			OccurredAt: now,
		},
		{
			Type:       notification.TaskEventFailed,
			TaskID:     "task-2",
			Status:     "failed",
			Attempt:    2,
			Reason:     "execution-error",
			OccurredAt: now,
		},
		{
			Type:       notification.TaskEventCompleted,
			TaskID:     "task-3",
			Status:     "completed",
			Attempt:    3,
			Reason:     "success-after-retries",
			OccurredAt: now,
		},
	}
	for _, e := range events {
		if err := service.NotifyTaskEvent(context.Background(), e); err != nil {
			t.Fatalf("unexpected error for %s: %v", e.Type, err)
		}
	}

	if len(sink.events) != 3 {
		t.Fatalf("expected sink to receive 3 events, got %d", len(sink.events))
	}
	if sink.events[0].Type != notification.TaskEventRunning || sink.events[1].Type != notification.TaskEventFailed {
		t.Errorf("sink did not receive non-completed events: %+v", sink.events)
	}
	if sink.events[2].Type != notification.TaskEventCompleted {
		t.Errorf("sink did not receive completed event: %+v", sink.events)
	}

	// Assert additive fields are preserved and fanned out
	for i, e := range events {
		got := sink.events[i]
		if got.Attempt != e.Attempt {
			t.Errorf("event %d: expected attempt %d, got %d", i, e.Attempt, got.Attempt)
		}
		if got.Reason != e.Reason {
			t.Errorf("event %d: expected reason %q, got %q", i, e.Reason, got.Reason)
		}
		if !got.OccurredAt.Equal(e.OccurredAt) {
			t.Errorf("event %d: expected occurred_at %v, got %v", i, e.OccurredAt, got.OccurredAt)
		}
	}
}

func TestNotifyTaskEventReturnsSinkErrors(t *testing.T) {
	logger := slog.New(&spyHandler{})
	sinkErr := errors.New("sink boom")
	sink := &recordingSink{err: sinkErr}
	service := notification.NewService(nil, logger, sink)

	err := service.NotifyTaskEvent(context.Background(), notification.TaskEvent{
		Type:   notification.TaskEventRunning,
		TaskID: "task-1",
		Status: "running",
	})
	if err == nil {
		t.Fatal("expected sink error to be returned")
	}
	if !errors.Is(err, sinkErr) {
		t.Errorf("expected joined error to wrap sink error, got %v", err)
	}
}

func TestNotifyTaskEventAllowsFailedWithoutMattermost(t *testing.T) {
	spy := &spyHandler{}
	logger := slog.New(spy)

	service := notification.NewService(nil, logger)

	err := service.NotifyTaskEvent(context.Background(), notification.TaskEvent{
		Type:    notification.TaskEventFailed,
		TaskID:  "task-456",
		Title:   "Failed Task",
		Status:  "failed",
		Message: "Something went wrong",
	})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	found := false
	for _, rec := range spy.records {
		if rec.msg == "task event notification requested" {
			found = true
			if rec.args["type"] != notification.TaskEventFailed {
				t.Errorf("expected event type %s, got %v", notification.TaskEventFailed, rec.args["type"])
			}
			if rec.args["task_id"] != "task-456" {
				t.Errorf("expected task_id task-456, got %v", rec.args["task_id"])
			}
		}
	}
	if !found {
		t.Error("expected 'task event notification requested' log message, not found")
	}
}

func TestNotifyTaskEventSendsMattermostOnlyForCompleted(t *testing.T) {
	var posts []mattermostPostBody
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/api/v4/posts" {
			t.Fatalf("path: got %s, want /api/v4/posts", r.URL.Path)
		}
		if got := r.Header.Get("Authorization"); got != "Bearer test-token" {
			t.Fatalf("authorization: got %q", got)
		}

		var body mattermostPostBody
		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
			t.Fatalf("decode request: %v", err)
		}
		posts = append(posts, body)
		w.WriteHeader(http.StatusCreated)
	}))
	defer server.Close()

	mattermostClient := mattermost.NewClientWithHTTPClient(mattermost.Config{
		BaseURL:   server.URL,
		Token:     "test-token",
		ChannelID: "task-channel",
	}, server.Client(), nil)
	service := notification.NewService(mattermostClient, nil)

	events := []notification.TaskEvent{
		{
			Type:    notification.TaskEventRunning,
			TaskID:  "task-running",
			Title:   "Running Task",
			Status:  "running",
			Message: "started",
		},
		{
			Type:    notification.TaskEventFailed,
			TaskID:  "task-failed",
			Title:   "Failed Task",
			Status:  "failed",
			Message: "failed",
		},
		{
			Type:    notification.TaskEventCompleted,
			TaskID:  "task-completed",
			Title:   "Completed Task",
			Status:  "completed",
			Message: "done",
		},
	}

	for _, event := range events {
		if err := service.NotifyTaskEvent(context.Background(), event); err != nil {
			t.Fatalf("NotifyTaskEvent(%s) returned error: %v", event.Type, err)
		}
	}

	if len(posts) != 1 {
		t.Fatalf("posts: got %d, want 1", len(posts))
	}
	if posts[0].ChannelID != "task-channel" {
		t.Fatalf("channel_id: got %q, want task-channel", posts[0].ChannelID)
	}
	for _, want := range []string{"Completed Task", "task-completed", "completed", "done"} {
		if !strings.Contains(posts[0].Message, want) {
			t.Fatalf("message %q does not contain %q", posts[0].Message, want)
		}
	}
}

func TestNotifyTaskEventReturnsMattermostError(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "mattermost unavailable", http.StatusBadGateway)
	}))
	defer server.Close()

	mattermostClient := mattermost.NewClientWithHTTPClient(mattermost.Config{
		BaseURL:   server.URL,
		Token:     "test-token",
		ChannelID: "task-channel",
	}, server.Client(), nil)
	service := notification.NewService(mattermostClient, nil)

	err := service.NotifyTaskEvent(context.Background(), notification.TaskEvent{
		Type:    notification.TaskEventCompleted,
		TaskID:  "task-completed",
		Title:   "Completed Task",
		Status:  "completed",
		Message: "done",
	})
	if err == nil {
		t.Fatal("expected error")
	}
	errText := err.Error()
	if !strings.Contains(errText, "status 502") || !strings.Contains(errText, "mattermost unavailable") {
		t.Fatalf("unexpected error: %v", err)
	}
}