package session

import (
	"git.yeij.top/AskaEth/Cyrene_v2/internal/capability/restrict"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/channel/adapter"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/user"
)

// ResolveActor 把一条归一化入站消息解析成下游权限决策所用的强类型 actor 元数据。
// 这是 design/11 §0 的结构化主人识别规则（裁决 06.4.2）：**owner 车道只认白名单**，
// 判主依据只有结构化来源——主人档案的账号白名单（owner.yaml，internal/user）与每渠道
// 账号配置的 adminIds[]（channels.json，design/08 §1.1）。
//
// **适配器上报的角色标记一律不得单独判主**：平台消息里的 role 字段（OneBot 的群主
// owner / 群管理员 admin，或私聊帧里伪造的 role=owner）只能当作非主人侧提示，命中
// owner 也会被降级为 RoleMember。判主永远不看消息正文——正文声称「我是主人」同样无效。
func ResolveActor(msg adapter.UnifiedMessage, owner *user.OwnerProfile) adapter.Actor {
	actor := adapter.Actor{
		Role:        msg.Sender.Role,
		UserID:      firstNonEmpty(msg.Sender.UserID, msg.SenderID),
		DisplayName: firstNonEmpty(msg.Sender.DisplayName, msg.SenderName),
		IsGroup:     msg.Sender.IsGroup || msg.IsGroup(),
		GroupID:     firstNonEmpty(msg.Sender.GroupID, msg.GroupID),
		GroupName:   firstNonEmpty(msg.Sender.GroupName, msg.GroupName),
	}

	// 白名单命中即主人；未命中则不管适配器上报了什么角色，都留在非主人车道
	// （owner.IsOwner 对 nil 档案安全返回 false）。
	if owner.IsOwner(msg.Platform, msg.SenderID) {
		actor.Role = adapter.RoleOwner
		return actor.Resolve()
	}
	actor.Role = nonOwnerRole(actor.Role)
	return actor.Resolve()
}

// nonOwnerRole 把适配器上报的角色收口到非主人车道：owner（群主 / 群管理员 / 伪造
// 字段）一律降级为 RoleMember；member / system / unknown 原样保留；非法值保守回落
// RoleMember，避免留下含糊角色。
func nonOwnerRole(role adapter.Role) adapter.Role {
	switch role {
	case adapter.RoleOwner:
		return adapter.RoleMember
	case adapter.RoleMember, adapter.RoleSystem, adapter.RoleUnknown:
		return role
	default:
		return adapter.RoleMember
	}
}

// EnvFor maps a resolved actor to the restrict.ActorEnv used to gate tools.
// Group chats always map to group_member (isolated, restricted) even when the
// owner is the speaker (design/02 §3: owner group speech stays in the isolated
// group context). A non-group owner maps to owner (full access); a non-group
// non-owner maps to stranger.
func EnvFor(actor adapter.Actor) restrict.ActorEnv {
	if actor.IsGroup {
		return restrict.ActorGroupMember
	}
	if actor.IsOwner() {
		return restrict.ActorOwner
	}
	return restrict.ActorStranger
}

// IdentifyContext 仅凭消息自带的渠道元数据推断 restrict.ActorEnv：群聊一律
// group_member，其余一律 stranger。它拿不到白名单，因此**不能授予 owner 车道**——
// 适配器上报的 role=owner 在此被降级为 member（裁决 06.4.2，owner 只认白名单）。
// 真正的判主走 ResolveActor(msg, owner) + EnvFor。
func IdentifyContext(msg adapter.UnifiedMessage) restrict.ActorEnv {
	actor := msg.Sender.Resolve()
	if msg.IsGroup() {
		actor.IsGroup = true
	}
	actor.Role = nonOwnerRole(actor.Role)
	return EnvFor(actor)
}

// Env returns the restrict actor environment for the session. It mirrors
// EnvFor: group chats are group_member regardless of membership, owner private
// is owner, and anything else is stranger.
func (s Session) Env() restrict.ActorEnv {
	if s.IsGroup {
		return restrict.ActorGroupMember
	}
	if s.Owner {
		return restrict.ActorOwner
	}
	return restrict.ActorStranger
}

// firstNonEmpty returns a when a is non-empty, otherwise b.
func firstNonEmpty(a, b string) string {
	if a != "" {
		return a
	}
	return b
}