package sop

import (
	"encoding/json"
	"fmt"

	"git.iwork-ai.com/xdc/iqudo-top1/internal/model"
)

var allowedNodeTypes = map[string]bool{"start": true, "message": true, "question": true, "form": true, "choice": true, "condition": true, "knowledge": true, "escalate": true, "finish": true}

func ValidateGraph(startNodeKey string, nodes []model.SOPNode, edges []model.SOPEdge) []string {
	var problems []string
	if startNodeKey == "" {
		problems = append(problems, "未设置开始节点")
	}
	nodeMap := make(map[string]model.SOPNode, len(nodes))
	startCount := 0
	finishCount := 0
	for _, node := range nodes {
		if node.NodeKey == "" {
			problems = append(problems, "存在没有标识的节点")
			continue
		}
		if _, exists := nodeMap[node.NodeKey]; exists {
			problems = append(problems, fmt.Sprintf("节点标识重复：%s", node.NodeKey))
		}
		nodeMap[node.NodeKey] = node
		if !allowedNodeTypes[node.Type] {
			problems = append(problems, fmt.Sprintf("节点 %s 类型不支持", node.Title))
		}
		if node.Type == "start" {
			startCount++
		}
		if node.Type == "finish" || node.Type == "escalate" {
			finishCount++
		}
	}
	if startCount != 1 {
		problems = append(problems, "流程必须且只能包含一个开始节点")
	}
	if finishCount == 0 {
		problems = append(problems, "流程至少需要一个结束或转人工节点")
	}
	if _, exists := nodeMap[startNodeKey]; !exists && startNodeKey != "" {
		problems = append(problems, "开始节点不存在")
	}

	adjacency := make(map[string][]string)
	outgoing := make(map[string]int)
	for _, edge := range edges {
		if _, exists := nodeMap[edge.SourceNodeKey]; !exists {
			problems = append(problems, fmt.Sprintf("连线起点不存在：%s", edge.SourceNodeKey))
		}
		if _, exists := nodeMap[edge.TargetNodeKey]; !exists {
			problems = append(problems, fmt.Sprintf("连线终点不存在：%s", edge.TargetNodeKey))
		}
		if len(edge.Condition) > 0 && !json.Valid(edge.Condition) {
			problems = append(problems, fmt.Sprintf("连线 %s -> %s 的条件不是有效 JSON", edge.SourceNodeKey, edge.TargetNodeKey))
		}
		adjacency[edge.SourceNodeKey] = append(adjacency[edge.SourceNodeKey], edge.TargetNodeKey)
		outgoing[edge.SourceNodeKey]++
	}
	for _, node := range nodes {
		if node.Type != "finish" && node.Type != "escalate" && outgoing[node.NodeKey] == 0 {
			problems = append(problems, fmt.Sprintf("节点“%s”没有下一步", node.Title))
		}
	}

	visited := map[string]bool{}
	var walk func(string)
	walk = func(key string) {
		if visited[key] {
			return
		}
		visited[key] = true
		for _, next := range adjacency[key] {
			walk(next)
		}
	}
	if startNodeKey != "" {
		walk(startNodeKey)
	}
	for key, node := range nodeMap {
		if !visited[key] {
			problems = append(problems, fmt.Sprintf("节点“%s”无法从开始节点到达", node.Title))
		}
	}
	return problems
}