package cqrs_test

import (
	"context"
	"errors"
	"log"
	"reflect"
	"testing"

	"gitstormr.dev/code-raider/gravity-wells/cqrs"
)

type testEvent struct {
	Echo string
}

type testCommand struct {
	Echo string
}

type testQuery struct {
	Echo string
}

type successCommandHandler struct {
	SendEvent bool
}

func (s *successCommandHandler) Handle(
	ctx context.Context, cmd cqrs.Command,
) ([]cqrs.Event, error) {
	command, _ := cmd.(*testCommand)

	log.Printf("Processing command: %s\n", command.Echo)

	if s.SendEvent {
		return []cqrs.Event{testEvent{Echo: command.Echo}}, nil
	} else {
		return nil, nil
	}
}

type successEventHandler struct{}

func (e *successEventHandler) Handle(
	ctx context.Context, evt cqrs.Event,
) error {
	event, _ := evt.(testEvent)
	log.Printf("Processing event: %s\n", event.Echo)
	return nil
}

type failureCommandHandler struct{}

func (e *failureCommandHandler) Handle(
	ctx context.Context, cmd cqrs.Command,
) ([]cqrs.Event, error) {
	return nil, errors.New("failed")
}

type successQueryHandler struct{}

func (e *successQueryHandler) Handle(
	ctx context.Context, query cqrs.Query,
) (interface{}, error) {
	return query, nil
}

type failureQueryHandler struct{}

func (e *failureQueryHandler) Handle(
	ctx context.Context, query cqrs.Query,
) (interface{}, error) {
	return nil, errors.New("failed")
}

type failureEventHandler struct{}

func (e *failureEventHandler) Handle(
	ctx context.Context, evt cqrs.Event,
) error {
	return errors.New("failed")
}

func logTestCommandMiddleware(next cqrs.CommandHandler) cqrs.CommandHandler {
	return cqrs.CommandHandlerFunc(
		func(ctx context.Context, cmd cqrs.Command) ([]cqrs.Event, error) {
			log.Printf("Received command: %s\n", cmd)
			return next.Handle(ctx, cmd)
		},
	)
}

func logTestQueryMiddleware(next cqrs.QueryHandler) cqrs.QueryHandler {
	return cqrs.QueryHandlerFunc(
		func(ctx context.Context, query cqrs.Query) (cqrs.Query, error) {
			log.Printf("Received query: %s\n", query)
			return next.Handle(ctx, query)
		},
	)
}

func logTestEventMiddleware(next cqrs.EventHandler) cqrs.EventHandler {
	return cqrs.EventHandlerFunc(
		func(ctx context.Context, evt cqrs.Event) error {
			log.Printf("Received event: %s\n", evt)
			return next.Handle(ctx, evt)
		},
	)
}

func TestNewRuneBringer(t *testing.T) {
	bus := cqrs.NewSingularity()

	if bus == nil {
		t.Error("RuneBringer should not be nil")
	}

	busType := reflect.TypeOf(bus)

	if busType.Kind() == reflect.Ptr {
		busType = busType.Elem()
	}

	if busType.Name() != "singularity" {
		t.Errorf(
			"RuneBringer should be of type RuneBringer, got %s", busType.Name(),
		)
	}
}

func TestRuneBringer_CommandHandle(t *testing.T) {
	tests := []struct {
		SendEvent bool
	}{
		{true},
		{false},
	}

	for _, tt := range tests {
		bus := cqrs.NewSingularity()
		bus.UseCommandMiddleware(logTestCommandMiddleware)
		bus.UseEventMiddleware(logTestEventMiddleware)
		bus.RegisterCommandHandler(
			&testCommand{}, &successCommandHandler{SendEvent: tt.SendEvent},
		)
		bus.RegisterEventHandler(&testEvent{}, &successEventHandler{})
		events, err := bus.ExecuteCommand(
			context.Background(), &testCommand{Echo: "Hello"},
		)
		if err != nil {
			t.Error("Error should be nil")
		}

		if tt.SendEvent {
			if len(events) == 0 {
				t.Errorf("Expected 1 event, got %d", len(events))
			}
		} else {
			if len(events) != 0 {
				t.Errorf("Expected 0 events, got %d", len(events))
			}
		}
	}
}

func TestRuneBringer_CommandHandleFailure(t *testing.T) {
	bus := cqrs.NewSingularity()
	bus.UseCommandMiddleware(logTestCommandMiddleware)
	bus.RegisterCommandHandler(
		&testCommand{}, &failureCommandHandler{},
	)
	_, err := bus.ExecuteCommand(
		context.Background(), &testCommand{Echo: "Hello"},
	)
	if err == nil {
		t.Error("Error should not be nil")
	}
}

func TestRuneBringer_CommandMissingHandler(t *testing.T) {
	bus := cqrs.NewSingularity()
	bus.UseCommandMiddleware(logTestCommandMiddleware)
	_, err := bus.ExecuteCommand(
		context.Background(), &testCommand{Echo: "Hello"},
	)
	if err == nil {
		t.Error("Error should not be nil")
	}
}

func TestRuneBringer_CommandHandleEventFailure(t *testing.T) {
	tests := []struct {
		SendEvent    bool
		EventHandler cqrs.EventHandler
	}{
		{true, &failureEventHandler{}},
		{true, nil},
		{false, nil},
	}

	for _, tt := range tests {
		bus := cqrs.NewSingularity()
		bus.UseCommandMiddleware(logTestCommandMiddleware)
		bus.RegisterCommandHandler(
			&testCommand{}, &successCommandHandler{SendEvent: tt.SendEvent},
		)

		if tt.EventHandler != nil {
			bus.RegisterEventHandler(&testEvent{}, tt.EventHandler)
		}

		_, err := bus.ExecuteCommand(
			context.Background(), &testCommand{Echo: "Hello"},
		)
		bus.RegisterEventHandler(&testEvent{}, tt.EventHandler)
		if tt.SendEvent && tt.EventHandler != nil {
			if err == nil {
				t.Error("Error should not be nil")
			}
		} else {
			if err != nil {
				t.Error("Error should be nil")
			}
		}
	}
}

func TestRuneBringer_QueryHandle(t *testing.T) {
	bus := cqrs.NewSingularity()
	bus.UseQueryMiddleware(logTestQueryMiddleware)
	bus.RegisterQueryHandler(
		&testQuery{}, &successQueryHandler{},
	)

	result, err := bus.ExecuteQuery(
		context.Background(), &testQuery{Echo: "Hello"},
	)
	if err != nil {
		t.Error("Error should be nil")
	}

	if result == nil {
		t.Error("Result should not be nil")
	}
}

func TestRuneBringer_QueryHandleFailure(t *testing.T) {
	bus := cqrs.NewSingularity()
	bus.UseQueryMiddleware(logTestQueryMiddleware)
	bus.RegisterQueryHandler(
		&testQuery{}, &failureQueryHandler{},
	)

	_, err := bus.ExecuteQuery(
		context.Background(), &testQuery{Echo: "Hello"},
	)
	if err == nil {
		t.Error("Error should not be nil")
	}
}

func TestRuneBringer_QueryMissingHandler(t *testing.T) {
	bus := cqrs.NewSingularity()
	bus.UseQueryMiddleware(logTestQueryMiddleware)

	_, err := bus.ExecuteQuery(
		context.Background(), &testQuery{Echo: "Hello"},
	)
	if err == nil {
		t.Error("Error should not be nil")
	}
}