package httpapi

import (
	"context"
	"errors"
	"knowledge-governance/internal/governance"
	"knowledge-governance/internal/librarysnapshot"
)

type librarySourceCandidateStore interface {
	LibrarySourceCandidate(context.Context, string, string) (governance.LibraryVersion, bool, error)
}

func configuredLibrarySource(config Config, scope string) governance.LibrarySourceIdentity {
	kb := config.LibrarySourceInternalKB
	if scope == "external" {
		kb = config.LibrarySourceExternalKB
	}
	return governance.LibrarySourceIdentity{Project: config.LibrarySourceProject, App: config.LibrarySourceApp, Scope: scope, TenantID: config.LibrarySourceTenantID, KnowledgeBaseID: kb}
}

func currentSourceCandidate(ctx context.Context, config Config, scope string) (*librarySnapshotView, error) {
	source := configuredLibrarySource(config, scope)
	id, err := source.ID()
	if err != nil {
		return nil, err
	}
	store, ok := config.Store.(librarySourceCandidateStore)
	if !ok {
		return nil, errors.New("source candidate exact query unavailable")
	}
	candidate, found, err := store.LibrarySourceCandidate(ctx, scope, id)
	if err != nil {
		return nil, err
	}
	if !found {
		return nil, errors.New("当前来源没有已绑定封存；旧快照须以原捕获证据核验关联，不能继承其他来源")
	}
	if candidate.Kind != governance.LibraryVersionTestSealed || candidate.Scope != scope || candidate.Evidence["source_id"] != id {
		return nil, errors.New("candidate source binding mismatch")
	}
	archive, err := librarysnapshot.Open(config.LibraryArchiveRoot, 256*1024*1024)
	if err != nil {
		return nil, err
	}
	defer archive.Close()
	manifest, err := archive.Load(candidate.SnapshotID)
	if err != nil {
		return nil, err
	}
	if manifest.Scope != scope || manifest.TenantID != source.TenantID || manifest.KnowledgeBaseID != source.KnowledgeBaseID {
		return nil, errors.New("candidate manifest differs from configured source")
	}
	view := librarySnapshotViewOfNoUsage(candidate.SnapshotID, manifest)
	view.SourceID = id
	view.SourceIdentity = &source
	return &view, nil
}