/**
 * 聊天全局状态：会话列表、各会话消息列表，供 composables 与页面共享
 */
import { reactive } from 'vue'

export const chatStore = reactive({
	// 会话列表（来自 getContacts）
	contacts: [],
	loadingContacts: false,
	/** 最近一次拉取会话列表是否因网络/接口失败（用于空列表时区分「请下拉刷新」与「暂无消息」） */
	contactsFetchFailed: false,

	// 按 contactId 存消息列表
	messages: {},
	// 已加载过历史的 contactId 集合，避免重复拉取
	loadedContactIds: {},
	// 当前正在查看的会话，用于前台/后台消息通知判断
	activeContactId: '',
	// 某会话是否正在加载更多
	loadingMore: {},

	/** 登出 / 清空 token 时重置，避免换账号仍显示上一用户会话与消息 */
	reset() {
		this.contacts = []
		this.loadingContacts = false
		this.contactsFetchFailed = false
		this.messages = {}
		this.loadedContactIds = {}
		this.activeContactId = ''
		this.loadingMore = {}
		this.setTabBarUnreadFromServer(0)
	},

	setContacts(list) {
		this.contacts = list || []
	},

	/** 仅更新某会话在列表中的最后一条预览与时间（WS 收到新消息时本地更新，不整表刷新） */
	updateContactPreview(contactId, { lastMessage, time }) {
		const id = String(contactId)
		const list = this.contacts || []
		const idx = list.findIndex((c) => String(c.user_id || c.id) === id)
		if (idx === -1) return
		const next = list.slice()
		next[idx] = { ...next[idx], lastMessage: lastMessage ?? next[idx].lastMessage, time: time ?? next[idx].time }
		this.contacts = next
	},

	setMessagesForContact(contactId, list, append = false) {
		const id = String(contactId)
		if (!this.messages[id]) this.messages[id] = []
		if (append) {
			this.messages[id].push(...list)
		} else {
			const current = this.messages[id] || []
			const tempMessages = current.filter((m) => m.tempId != null)
			// 合并接口历史与 store 里已有消息（含 WS 推送），避免点进会话时把实时收到的消息冲掉
			const existingStable = current.filter((m) => !m.tempId)
			const apiList = list || []
			const seen = new Set()
			const merged = []
			for (const m of [...apiList, ...existingStable]) {
				const k = String(m.id || m.tempId || '')
				if (seen.has(k)) continue
				seen.add(k)
				merged.push(m)
			}
			merged.sort((a, b) => {
				const ta = (a.createdAt && new Date(a.createdAt).getTime()) || 0
				const tb = (b.createdAt && new Date(b.createdAt).getTime()) || 0
				return ta - tb
			})
			this.messages[id] = [...merged, ...tempMessages]
		}
	},

	prependMessages(contactId, list) {
		const id = String(contactId)
		if (!this.messages[id]) this.messages[id] = []
		const merged = (list || []).concat(this.messages[id])
		// 按 id 去重，保留首次出现（历史在前，避免重复）
		const seen = new Set()
		this.messages[id] = merged.filter((m) => {
			const k = m.id || m.tempId
			if (seen.has(k)) return false
			seen.add(k)
			return true
		})
	},

	appendMessage(contactId, message) {
		const id = String(contactId)
		const prev = this.messages[id] || []
		this.messages[id] = [...prev, message]
	},

	replaceTempMessage(contactId, tempId, serverMessage) {
		const id = String(contactId)
		const list = this.messages[id]
		if (!list || !list.length) return
		const idx = list.findIndex((m) => m.id === tempId || m.tempId === tempId)
		if (idx !== -1) {
			this.messages[id] = [...list.slice(0, idx), serverMessage, ...list.slice(idx + 1)]
		}
	},

	/** 按 id / tempId 移除一条（如再次提醒发送失败时撤回临时消息） */
	removeMessage(contactId, messageId) {
		const id = String(contactId)
		const list = this.messages[id]
		if (!list || !list.length) return
		this.messages[id] = list.filter((m) => m.id !== messageId && m.tempId !== messageId)
	},

	/** 更新某条消息（如 status: 'sending' / 'failed'） */
	updateMessage(contactId, tempIdOrId, updates) {
		const id = String(contactId)
		const list = this.messages[id]
		if (!list || !list.length) return
		const idx = list.findIndex((m) => m.id === tempIdOrId || m.tempId === tempIdOrId)
		if (idx !== -1) {
			const next = list.slice()
			next[idx] = { ...next[idx], ...updates }
			this.messages[id] = next
		}
	},

	markContactLoaded(contactId) {
		this.loadedContactIds[String(contactId)] = true
	},

	hasContactLoaded(contactId) {
		return !!this.loadedContactIds[String(contactId)]
	},

	setActiveContact(contactId) {
		this.activeContactId = contactId ? String(contactId) : ''
	},

	/**
	 * 底部「消息」Tab 角标（index 0），数值来自 GET /messages/unread-count
	 * @param {number|string} n - 未读总数
	 */
	setTabBarUnreadFromServer(n) {
		const total = Math.max(0, Number(n) || 0)
		try {
			if (total <= 0) {
				uni.removeTabBarBadge({ index: 0 })
			} else {
				uni.setTabBarBadge({ index: 0, text: total > 99 ? '99+' : String(total) })
			}
		} catch (e) {
			// 非 Tab 页或未就绪时可能报错，忽略
		}
	}
})