package usecase

import (
	"context"
	"fmt"
	"strings"

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

type resolvedPromptDefinition struct {
	definition *domain.PromptDefinition
	hash       string
}

func (r *Runner) resolvePromptDefinition(
	ctx context.Context,
	promptID string,
	promptVersion string,
) (*resolvedPromptDefinition, error) {
	if strings.TrimSpace(promptID) == "" {
		return nil, fmt.Errorf("%w: prompt id is required", ErrInvalidRequest)
	}
	if r == nil || r.promptDefs == nil {
		return nil, fmt.Errorf("%w: prompt repository is not configured", ErrPromptLoad)
	}

	definition, err := r.promptDefs.GetPromptDefinition(ctx, promptID, promptVersion)
	if err != nil {
		return nil, fmt.Errorf("%w: %w", ErrPromptLoad, err)
	}
	if definition == nil {
		return nil, fmt.Errorf("%w: prompt repository returned nil definition", ErrPromptLoad)
	}

	hash, err := hashPromptDefinition(definition)
	if err != nil {
		return nil, fmt.Errorf("%w: failed to hash prompt definition: %v", ErrPromptLoad, err)
	}
	return &resolvedPromptDefinition{definition: definition, hash: hash}, nil
}

// InspectPrompt resolves one explicit prompt without execution work.
func (r *Runner) InspectPrompt(
	ctx context.Context,
	promptID string,
	promptVersion string,
) (*domain.PromptInspection, error) {
	if strings.TrimSpace(promptID) == "" {
		return nil, fmt.Errorf("%w: prompt id is required", ErrInvalidRequest)
	}
	select {
	case <-ctx.Done():
		return nil, fmt.Errorf("%w: %w", ErrPromptLoad, ctx.Err())
	default:
	}

	selection, err := r.resolvePromptDefinition(ctx, promptID, promptVersion)
	if err != nil {
		return nil, err
	}
	inputs := make([]domain.PromptInput, len(selection.definition.Inputs))
	copy(inputs, selection.definition.Inputs)

	return &domain.PromptInspection{
		PromptID:         selection.definition.ID,
		PromptVersion:    selection.definition.Version,
		PromptHash:       selection.hash,
		DefaultProfileID: selection.definition.DefaultProfile,
		Inputs:           inputs,
		OutputContract:   selection.definition.Validation,
	}, nil
}