package usecase

import (
	"context"
	"fmt"
	"strings"

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

// RequirementInspectionRequest selects a captured prompt and supplies the
// context used for dependency classification.
type RequirementInspectionRequest struct {
	PromptID  string
	ProfileID string
	Vars      map[string]string
	SessionID string
}

type requirementSnapshotRepository interface {
	GetRequirementSnapshot(id string) (prompt.RequirementSnapshot, bool)
}

// InspectRequirements discovers prompt inputs and caller variables without
// loading artifacts or performing execution preparation.
func (r *Runner) InspectRequirements(
	ctx context.Context,
	req RequirementInspectionRequest,
) (*domain.RequirementInspection, error) {
	if strings.TrimSpace(req.PromptID) == "" {
		return nil, fmt.Errorf("%w: prompt id is required", ErrInvalidRequest)
	}
	directSessionID, err := domain.NormalizeSessionID(req.SessionID)
	if err != nil {
		return nil, fmt.Errorf("%w: session_id: %v", ErrInvalidRequest, err)
	}
	if err := ctx.Err(); err != nil {
		return nil, fmt.Errorf("%w: %w", ErrPromptLoad, err)
	}

	selection, err := r.resolvePromptInspection(ctx, req.PromptID)
	if err != nil {
		return nil, err
	}
	if err := ctx.Err(); err != nil {
		return nil, fmt.Errorf("%w: %w", ErrProfileLoad, err)
	}
	selectedProfileID := req.ProfileID
	if strings.TrimSpace(selectedProfileID) == "" {
		selectedProfileID = selection.DefaultProfileID
	}
	if strings.TrimSpace(selectedProfileID) == "" {
		return nil, fmt.Errorf("%w: %w: profile id is required either in request or prompt default_profile", ErrInvalidRequest, ErrProfileRequired)
	}
	profileIdentity, err := r.resolveProfileIdentity(ctx, selectedProfileID)
	if err != nil {
		return nil, err
	}
	if err := ctx.Err(); err != nil {
		return nil, fmt.Errorf("%w: %w", ErrPromptLoad, err)
	}

	repository, ok := r.promptDefs.(requirementSnapshotRepository)
	if !ok {
		return nil, fmt.Errorf("%w: prompt repository does not provide captured requirement snapshots", ErrPromptLoad)
	}
	snapshot, ok := repository.GetRequirementSnapshot(selection.PromptID)
	if !ok {
		return nil, fmt.Errorf("%w: captured requirement snapshot is unavailable", ErrPromptLoad)
	}
	definition := &domain.PromptDefinition{ID: selection.PromptID, Version: copyStringPointer(selection.PromptVersion)}
	inspection, err := prompt.AnalyzeRequirements(ctx, definition, snapshot, req.Vars, directSessionID != "")
	if err != nil {
		return nil, fmt.Errorf("%w: %w", ErrPromptLoad, err)
	}
	inspection.ProfileID = profileIdentity
	return &inspection, nil
}