package projectinstance

import (
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"sort"
)

func computePlanHash(plan WorkflowPlan) (string, error) {
	normalized := normalizePlan(plan)
	raw, err := json.Marshal(normalized)
	if err != nil {
		return "", err
	}
	sum := sha256.Sum256(raw)
	return hex.EncodeToString(sum[:]), nil
}

func normalizePlan(plan WorkflowPlan) WorkflowPlan {
	out := plan
	sort.Slice(out.Stages, func(i, j int) bool {
		return out.Stages[i].StageKey < out.Stages[j].StageKey
	})
	for i := range out.Stages {
		sort.Slice(out.Stages[i].DocTasks, func(a, b int) bool {
			return out.Stages[i].DocTasks[a].TaskKey < out.Stages[i].DocTasks[b].TaskKey
		})
	}
	return out
}