package noop

import (
	"context"
	"encoding/json"
	"fmt"

	"gitea.maximumdirect.net/eric/notarius/internal/core/artifacts"
	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
)

const Key = "noop"

var _ contracts.Normalizer = (*Normalizer)(nil)

type Normalizer struct{}

func New() *Normalizer {
	return &Normalizer{}
}

func (n *Normalizer) Key() string {
	return Key
}

func (n *Normalizer) Normalize(ctx context.Context, req contracts.NormalizeRequest) (contracts.NormalizeResult, error) {
	if n == nil {
		return contracts.NormalizeResult{}, normalizerErrorf("normalizer must not be nil")
	}
	if ctx == nil {
		return contracts.NormalizeResult{}, normalizerErrorf("context must not be nil")
	}
	if err := ctx.Err(); err != nil {
		return contracts.NormalizeResult{}, normalizerErrorf("context error before normalize: %w", err)
	}
	return contracts.NormalizeResult{Candidates: cloneCandidates(req.Candidates)}, nil
}

func ModuleSpec() pipeline.ModuleSpec {
	return pipeline.ModuleSpec{
		Key:      Key,
		Stage:    pipeline.StageNormalize,
		Requires: []string{"merged"},
		Provides: []string{"normalized"},
	}
}

func Register(registry *pipeline.NormalizerRegistry) error {
	return registry.RegisterWithSpec(ModuleSpec(), func() (contracts.Normalizer, error) {
		return New(), nil
	})
}

func cloneCandidates(candidates []artifacts.ArtifactCandidate) []artifacts.ArtifactCandidate {
	if len(candidates) == 0 {
		return nil
	}

	out := make([]artifacts.ArtifactCandidate, 0, len(candidates))
	for _, candidate := range candidates {
		out = append(out, artifacts.ArtifactCandidate{
			Index:         candidate.Index,
			ExtractorKey:  candidate.ExtractorKey,
			ArtifactType:  candidate.ArtifactType,
			SchemaVersion: candidate.SchemaVersion,
			Payload:       append(json.RawMessage(nil), candidate.Payload...),
			SourceRefs:    append([]source.SourceRef(nil), candidate.SourceRefs...),
			Metadata:      cloneMetadata(candidate.Metadata),
		})
	}
	return out
}

func cloneMetadata(metadata map[string]any) map[string]any {
	if len(metadata) == 0 {
		return nil
	}
	out := make(map[string]any, len(metadata))
	for key, value := range metadata {
		out[key] = value
	}
	return out
}

func normalizerErrorf(format string, args ...any) error {
	return fmt.Errorf("noop normalizer: "+format, args...)
}