package docgov

import (
	"sort"

	"chat-agent-system/internal/workflowdef"
)

// collapseWorkflowDocuments 把同一发布键的旧键行与新键行收成一行。
// 发布键优先；都是发布键时保留已脱离模板的那条；再按 doc_id 稳定选取。
func collapseWorkflowDocuments(docs []WorkflowDocumentSummary) []WorkflowDocumentSummary {
	if len(docs) < 2 {
		return docs
	}
	best := make(map[string]WorkflowDocumentSummary, len(docs))
	for _, doc := range docs {
		canon := workflowdef.CanonicalTaskKey(doc.TaskKey)
		if canon == "" {
			continue
		}
		prev, ok := best[canon]
		if !ok {
			best[canon] = doc
			continue
		}
		best[canon] = preferWorkflowDocument(prev, doc)
	}
	out := make([]WorkflowDocumentSummary, 0, len(best))
	for _, doc := range best {
		out = append(out, doc)
	}
	sort.Slice(out, func(i, j int) bool {
		if out[i].TaskKey == out[j].TaskKey {
			return out[i].DocID < out[j].DocID
		}
		return out[i].TaskKey < out[j].TaskKey
	})
	return out
}

func preferWorkflowDocument(current, candidate WorkflowDocumentSummary) WorkflowDocumentSummary {
	currentPublished := current.TaskKey == workflowdef.CanonicalTaskKey(current.TaskKey)
	candidatePublished := candidate.TaskKey == workflowdef.CanonicalTaskKey(candidate.TaskKey)
	if currentPublished != candidatePublished {
		if candidatePublished {
			return candidate
		}
		return current
	}
	if current.IsTemplateOnly != candidate.IsTemplateOnly {
		if candidate.IsTemplateOnly {
			return current
		}
		return candidate
	}
	if candidate.DocID < current.DocID {
		return candidate
	}
	return current
}