package promptkit

import (
	"context"
	"errors"
	"fmt"
	"testing"

	"gitea.maximumdirect.net/eric/promptkit/internal/usecase"
)

func TestMapPublicErrorPreservesGenerationCancellation(t *testing.T) {
	internalErr := fmt.Errorf("%w: %w", usecase.ErrLLMGenerate, context.Canceled)

	err := mapPublicError(internalErr)
	if !errors.Is(err, ErrLLMGenerate) {
		t.Fatalf("mapped error=%v, want ErrLLMGenerate", err)
	}
	if !errors.Is(err, context.Canceled) {
		t.Fatalf("mapped error=%v, want context.Canceled", err)
	}
}

func TestMapPublicErrorTranslatesCapacityError(t *testing.T) {
	internalErr := &usecase.CapacityError{BackendID: "limited"}

	err := mapPublicError(internalErr)
	var publicErr *CapacityError
	if !errors.As(err, &publicErr) || publicErr == nil {
		t.Fatalf("mapped error=%v, want public CapacityError", err)
	}
	if publicErr.BackendID != "limited" {
		t.Fatalf("mapped backend ID=%q, want limited", publicErr.BackendID)
	}
	if !errors.Is(err, ErrCapacityExceeded) {
		t.Fatalf("mapped error=%v, want ErrCapacityExceeded", err)
	}
	if errors.Is(err, ErrInvalidRequest) || errors.Is(err, ErrLLMGenerate) {
		t.Fatalf("mapped capacity error has an unrelated category: %v", err)
	}
	var leakedInternalErr *usecase.CapacityError
	if errors.As(err, &leakedInternalErr) {
		t.Fatalf("mapped error exposes internal CapacityError: %v", err)
	}

	internalErr.BackendID = "changed"
	if publicErr.BackendID != "limited" {
		t.Fatalf("mapped backend ID changed with source error: %q", publicErr.BackendID)
	}
}