package normalize

import (
	"context"
	"fmt"

	"gitea.maximumdirect.net/ejr/feedkit/event"
)

// Processor applies ordered normalization rules to pipeline events.
//
// Selection rule:
//   - iterate in Normalizers order
//   - the first Normalizer whose Match returns true is applied
//
// If no normalizer matches, the default behavior is pass-through.
type Processor struct {
	Normalizers []Normalizer

	// If true, events that do not match any normalizer cause an error.
	// Default is false (pass-through).
	RequireMatch bool
}

// NewProcessor constructs a normalization processor from an ordered normalizer list.
func NewProcessor(normalizers []Normalizer, requireMatch bool) Processor {
	return Processor{
		Normalizers:  append([]Normalizer(nil), normalizers...),
		RequireMatch: requireMatch,
	}
}

// Process implements processors.Processor.
func (p Processor) Process(ctx context.Context, in event.Event) (*event.Event, error) {
	for _, n := range p.Normalizers {
		if n == nil {
			continue
		}
		if !n.Match(in) {
			continue
		}

		out, err := n.Normalize(ctx, in)
		if err != nil {
			return nil, fmt.Errorf("normalize: normalizer failed: %w", err)
		}
		return out, nil
	}

	if p.RequireMatch {
		return nil, fmt.Errorf("normalize: no normalizer matched event (id=%s kind=%s source=%s schema=%q)",
			in.ID, in.Kind, in.Source, in.Schema)
	}

	out := in
	return &out, nil
}