package utils

import "github.com/gogf/gf/v2/util/gconv"

// MergeNode 按模板节点的元数据把用户数据节点合并为模板可解析的节点：
//   - 用户节点无 type 键 → 套上模板类型包装（标量取用户值，空则回落模板 value/defaultValue）
//   - 用户节点有 type 键 → 递归合并子节点（子节点缺 type 时同样补模板类型，避免模板包装泄漏）
//   - 对象：模板 attrs 缺省字段补进用户容器（保留模板默认值）
//   - 数组：用户 enumValues/attrs 元素逐个与模板元素原型合并（模板未提供的槽位克隆原型）
func MergeNode(user, tmpl any) any {
	tmplMap, ok := tmpl.(map[string]any)
	if !ok {
		return user
	}
	fieldType, _ := tmplMap["type"].(string)

	// 用户节点已带 type：按用户类型递归合并子节点；标量叶子已完备，直接返回
	if userMap, ok := user.(map[string]any); ok {
		if ut, isTpl := userMap["type"]; isTpl {
			switch gconv.String(ut) {
			case TypeObject:
				return mergeObject(userMap, tmplMap)
			case TypeArray:
				return mergeArray(userMap, tmplMap)
			default:
				return userMap
			}
		}
	}

	switch fieldType {
	case TypeString, TypeBool, TypeNumber, TypeNumberInt, TypeNumberFloat:
		return wrapScalarNode(tmplMap, user)
	case TypeObject:
		return mergeObject(user, tmplMap)
	case TypeArray:
		return mergeArray(user, tmplMap)
	default:
		return user
	}
}

// wrapScalarNode 把用户标量值包装为 {type, value} 节点；用户值为空时回落模板 value/defaultValue
func wrapScalarNode(tmplMap map[string]any, user any) map[string]any {
	val := user
	if m, ok := user.(map[string]any); ok {
		if v, has := m["value"]; has {
			val = v
		} else {
			val = nil
		}
	}
	node := map[string]any{"type": normalizeScalarType(gconv.String(tmplMap["type"]))}
	if hasUsableValue(val) {
		node["value"] = val
	} else if v, has := tmplMap["value"]; has {
		node["value"] = v
	} else if d, has := tmplMap["defaultValue"]; has {
		node["value"] = d
	}
	return node
}

// normalizeScalarType integer/float 统一为 number（resolveField 只分发 string/boolean/number）
func normalizeScalarType(t string) string {
	if t == TypeNumberInt || t == TypeNumberFloat {
		return TypeNumber
	}
	return t
}

// mergeObject 合并对象节点：模板 attrs 缺省字段补进用户容器（模板默认值保留）
func mergeObject(user any, tmplMap map[string]any) map[string]any {
	tmplAttrs, _ := tmplMap["attrs"].(map[string]any)
	node := map[string]any{"type": TypeObject}
	if tmplAttrs == nil {
		node["attrs"] = user
		return node
	}
	var container map[string]any
	switch u := user.(type) {
	case map[string]any:
		if a, has := u["attrs"]; has {
			if am, ok := a.(map[string]any); ok {
				container = copyMap(am)
			} else {
				container = map[string]any{}
			}
		} else if v, has := u["value"]; has {
			if vm, ok := v.(map[string]any); ok {
				container = copyMap(vm)
			} else {
				container = map[string]any{}
			}
		} else {
			container = copyMap(u)
		}
	default:
		container = map[string]any{}
	}
	for k, subTmpl := range tmplAttrs {
		if _, has := container[k]; !has {
			container[k] = DeepCopyNode(subTmpl)
		} else {
			container[k] = MergeNode(container[k], subTmpl)
		}
	}
	node["attrs"] = container
	return node
}

// mergeArray 合并数组节点：用户 enumValues/attrs 元素逐个与模板元素原型合并。
// 用户未填的槽位（sjson null 填充）用模板对应槽位原型补位，保留下标不塌缩。
func mergeArray(user any, tmplMap map[string]any) map[string]any {
	proto := arrayElementTemplate(tmplMap)
	tmplSlots, _ := tmplMap["enumValues"].([]any) // 模板各槽位原型，按下标一一对应
	node := map[string]any{"type": TypeArray}
	slotProto := func(i int) any {
		if i < len(tmplSlots) {
			return tmplSlots[i]
		}
		return proto
	}
	switch u := user.(type) {
	case map[string]any:
		if evs, ok := u["enumValues"].([]any); ok {
			out := make([]any, len(evs))
			for i, ev := range evs {
				if ev == nil {
					// 保留 null 槽位以维持下标；解析阶段 resolveArray 会丢弃空元素，
					// 避免用模板原型填充 null 而物化出"幽灵"元素（用户未填的数组槽位）
					out[i] = nil
					continue
				}
				out[i] = mergeArrayElement(ev, slotProto(i))
			}
			node["enumValues"] = out
		} else if a, ok := u["attrs"].([]any); ok {
			out := make([]any, len(a))
			for i, item := range a {
				out[i] = mergeArrayElement(item, proto)
			}
			node["attrs"] = out
		} else if v, has := u["value"]; has {
			node["value"] = v
		} else if len(u) > 0 {
			node["attrs"] = []any{mergeArrayElement(u, proto)}
		}
	case []any:
		if isSchemaElementList(u) {
			out := make([]any, len(u))
			for i, item := range u {
				out[i] = mergeArrayElement(item, proto)
			}
			node["attrs"] = out
		} else {
			node["value"] = u
		}
	default:
		node["value"] = user
	}
	return node
}

// mergeArrayElement 合并单个数组元素：元素缺 type 时按槽位原型补默认字段。
// slotProto 可为 nil（模板未提供槽位原型时）→ 原样返回用户元素
func mergeArrayElement(ev any, slotProto any) any {
	if ev == nil {
		return ev
	}
	proto, _ := slotProto.(map[string]any)
	if proto == nil {
		return ev
	}
	evMap, ok := ev.(map[string]any)
	if !ok {
		return ev
	}
	if _, isTpl := evMap["type"]; isTpl {
		return ev
	}
	// 元素原型自身是包装节点（嵌套对象/数组）→ 按模板类型合并
	if t, has := proto["type"].(string); has && t != "" {
		return MergeNode(ev, proto)
	}
	protoAttrs, _ := proto["attrs"].(map[string]any)
	var container map[string]any
	if a, has := evMap["attrs"]; has {
		if am, ok := a.(map[string]any); ok {
			container = copyMap(am)
		} else {
			container = map[string]any{}
		}
	} else {
		container = copyMap(evMap)
	}
	for k, subTmpl := range protoAttrs {
		if _, has := container[k]; !has {
			container[k] = DeepCopyNode(subTmpl)
		} else {
			container[k] = MergeNode(container[k], subTmpl)
		}
	}
	return map[string]any{"attrs": container}
}

// isSchemaElementList 判断 []any 是否为 schema 元素列表（元素均为 map，且带 type 或 attrs 包装）
func isSchemaElementList(list []any) bool {
	if len(list) == 0 {
		return false
	}
	for _, item := range list {
		m, ok := item.(map[string]any)
		if !ok {
			return false
		}
		if _, hasType := m["type"]; !hasType {
			if _, hasAttrs := m["attrs"]; !hasAttrs {
				return false
			}
		}
	}
	return true
}

// DeepCopyNode 深拷贝任意嵌套节点（模板节点整体拷贝进 src 时使用，避免共享引用被后续回填修改）
func DeepCopyNode(v any) any {
	switch val := v.(type) {
	case map[string]any:
		out := make(map[string]any, len(val))
		for k, sub := range val {
			out[k] = DeepCopyNode(sub)
		}
		return out
	case []any:
		out := make([]any, len(val))
		for i, sub := range val {
			out[i] = DeepCopyNode(sub)
		}
		return out
	default:
		return v
	}
}

// hasUsableValue 值是否可写入节点 value；0/false 视为有效值
func hasUsableValue(v any) bool {
	switch val := v.(type) {
	case nil:
		return false
	case string:
		return val != ""
	case []any:
		return len(val) > 0
	case map[string]any:
		return len(val) > 0
	default:
		return true
	}
}