/**
 * 腾讯 IM SDK 封装
 * 负责初始化、登录、收发消息
 */
import TencentCloudChat from '@tencentcloud/chat'
import request from './request'

let chat = null
let isReady = false
let onMessageCallback = null

/**
 * 获取 IM 实例（单例）
 */
export function getChatInstance() {
	return chat
}

/**
 * 初始化并登录 IM
 * @returns {Promise<{sdkAppId, userId}>}
 */
export async function initIM() {
	// 从后端获取 UserSig
	const res = await request({ url: '/api/im/usersig' })
	const { sdkAppId, userId, userSig } = res

	// 创建 SDK 实例
	if (!chat) {
		chat = TencentCloudChat.create({ SDKAppID: sdkAppId })
		chat.setLogLevel(1) // Release 级别日志

		// 监听 SDK 就绪
		chat.on(TencentCloudChat.EVENT.SDK_READY, () => {
			console.log('[IM] SDK 就绪')
			isReady = true
		})

		// 监听新消息
		chat.on(TencentCloudChat.EVENT.MESSAGE_RECEIVED, (event) => {
			const msgList = event.data
			if (onMessageCallback) {
				onMessageCallback(msgList)
			}
		})

		// 监听被踢下线
		chat.on(TencentCloudChat.EVENT.KICKED_OUT, () => {
			console.log('[IM] 被踢下线')
			isReady = false
		})
	}

	// 登录
	await chat.login({ userID: userId, userSig })
	console.log('[IM] 登录成功:', userId)
	return { sdkAppId, userId }
}

/**
 * 登出 IM
 */
export async function logoutIM() {
	if (chat) {
		await chat.logout()
		isReady = false
		console.log('[IM] 已登出')
	}
}

/**
 * 设置新消息回调
 * @param {Function} callback - 接收消息列表的回调
 */
export function onNewMessage(callback) {
	onMessageCallback = callback
}

/**
 * 移除新消息回调
 */
export function offNewMessage() {
	onMessageCallback = null
}

/**
 * 获取会话 ID（C2C 单聊）
 * @param {string} targetUserId - 对方用户 ID（如 user_123）
 */
export function getConversationId(targetUserId) {
	return `C2C${targetUserId}`
}

/**
 * 获取会话列表（用于消息页展示聊天记录）
 * @returns {Promise<Array>} 会话列表
 */
export async function getConversationList() {
	if (!chat || !isReady) return []
	try {
		const res = await chat.getConversationList()
		const list = res.data.conversationList || []
		// 只返回 C2C 单聊会话
		return list
			.filter(c => c.type === TencentCloudChat.TYPES.CONV_C2C)
			.map(c => {
				const lastMsg = c.lastMessage
				let lastMessageText = ''
				if (lastMsg) {
					if (lastMsg.type === TencentCloudChat.TYPES.MSG_TEXT) {
						lastMessageText = lastMsg.payload?.text || ''
					} else if (lastMsg.type === TencentCloudChat.TYPES.MSG_IMAGE) {
						lastMessageText = '[图片]'
					} else if (lastMsg.type === TencentCloudChat.TYPES.MSG_CUSTOM) {
						lastMessageText = lastMsg.payload?.description || '[自定义消息]'
					} else {
						lastMessageText = '[消息]'
					}
				}
				return {
					conversationID: c.conversationID,
					targetUserId: c.userProfile?.userID || c.conversationID.replace('C2C', ''),
					nickname: c.userProfile?.nick || c.conversationID.replace('C2C', ''),
					avatarUrl: c.userProfile?.avatar || '',
					lastMessage: lastMessageText,
					lastMessageTime: lastMsg ? lastMsg.lastTime * 1000 : 0,
					unreadCount: c.unreadCount || 0
				}
			})
			.sort((a, b) => b.lastMessageTime - a.lastMessageTime)
	} catch (e) {
		console.error('[IM] 获取会话列表失败:', e)
		return []
	}
}

/**
 * 拉取历史消息
 * @param {string} targetUserId - 对方用户 ID
 * @param {string} [nextReqMessageID] - 分页标记
 * @returns {Promise<{messageList, isCompleted, nextReqMessageID}>}
 */
export async function getMessageList(targetUserId, nextReqMessageID) {
	const conversationID = getConversationId(targetUserId)
	const res = await chat.getMessageList({
		conversationID,
		nextReqMessageID,
		count: 20
	})
	return {
		messageList: res.data.messageList || [],
		isCompleted: res.data.isCompleted,
		nextReqMessageID: res.data.nextReqMessageID
	}
}

/**
 * 发送文本消息
 * @param {string} targetUserId - 对方用户 ID
 * @param {string} text - 文本内容
 */
export async function sendTextMessage(targetUserId, text) {
	const message = chat.createTextMessage({
		to: targetUserId,
		conversationType: TencentCloudChat.TYPES.CONV_C2C,
		payload: { text }
	})
	const res = await chat.sendMessage(message)
	return res.data.message
}

/**
 * 发送图片消息
 * @param {string} targetUserId - 对方用户 ID
 * @param {string} filePath - 本地图片路径
 */
export async function sendImageMessage(targetUserId, filePath) {
	const message = chat.createImageMessage({
		to: targetUserId,
		conversationType: TencentCloudChat.TYPES.CONV_C2C,
		payload: { file: { tempFilePaths: [filePath] } }
	})
	const res = await chat.sendMessage(message)
	return res.data.message
}

/**
 * 发送自定义消息（改价申请等）
 * @param {string} targetUserId - 对方用户 ID
 * @param {Object} customData - 自定义数据
 */
export async function sendCustomMessage(targetUserId, customData) {
	const message = chat.createCustomMessage({
		to: targetUserId,
		conversationType: TencentCloudChat.TYPES.CONV_C2C,
		payload: {
			data: JSON.stringify(customData),
			description: customData.description || '',
			extension: customData.extension || ''
		}
	})
	const res = await chat.sendMessage(message)
	return res.data.message
}

/**
 * 将 IM 消息转换为聊天页展示格式
 * @param {Object} msg - IM SDK 消息对象
 * @param {string} currentImUserId - 当前用户 IM ID
 * @returns {Object} 聊天页消息格式
 */
export function formatIMMessage(msg, currentImUserId) {
	const isSelf = msg.from === currentImUserId
	const avatar = msg.avatar || '/static/logo.png'

	// 文本消息
	if (msg.type === TencentCloudChat.TYPES.MSG_TEXT) {
		return {
			id: msg.ID,
			type: 'text',
			content: msg.payload.text,
			isSelf,
			avatar,
			time: msg.time * 1000
		}
	}

	// 图片消息
	if (msg.type === TencentCloudChat.TYPES.MSG_IMAGE) {
		const imageInfo = msg.payload.imageInfoArray?.[1] || msg.payload.imageInfoArray?.[0]
		return {
			id: msg.ID,
			type: 'image',
			content: imageInfo?.url || '',
			isSelf,
			avatar,
			time: msg.time * 1000
		}
	}

	// 自定义消息（改价等）
	if (msg.type === TencentCloudChat.TYPES.MSG_CUSTOM) {
		try {
			const data = JSON.parse(msg.payload.data)
			if (data.bizType === 'price-change') {
				return {
					id: msg.ID,
					type: 'price-change',
					isSelf,
					priceChangeId: data.priceChangeId,
					changeTypeLabel: data.changeTypeLabel,
					originalPrice: data.originalPrice,
					newPrice: data.newPrice,
					difference: data.difference,
					status: data.status,
					time: msg.time * 1000
				}
			}
		} catch (e) {
			// 解析失败当普通文本处理
		}
		return {
			id: msg.ID,
			type: 'text',
			content: msg.payload.description || '[自定义消息]',
			isSelf,
			avatar,
			time: msg.time * 1000
		}
	}

	// 其他类型
	return {
		id: msg.ID,
		type: 'text',
		content: '[暂不支持的消息类型]',
		isSelf,
		avatar,
		time: msg.time * 1000
	}
}