112 lines
3.8 KiB
JavaScript
112 lines
3.8 KiB
JavaScript
const cloud = require('wx-server-sdk')
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cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
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const db = cloud.database()
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const _ = db.command
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async function fetchUsers(ids) {
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if (!ids.length) return []
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const out = []
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for (let i = 0; i < ids.length; i += 100) {
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const chunk = ids.slice(i, i + 100)
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const res = await db.collection('users').where({ _id: _.in(chunk) }).limit(100).get()
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out.push(...res.data)
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}
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return out
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}
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function hashId(id) {
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let h = 5381
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for (let i = 0; i < id.length; i++) {
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h = ((h << 5) + h) ^ id.charCodeAt(i)
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h = h >>> 0 // keep as unsigned 32-bit
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}
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return h
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}
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// Generate a stable map pin position from pet id (fallback abstract layer)
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function stablePin(id) {
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const h = hashId(id)
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const left = 10 + (h % 70)
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const top = 15 + ((h >> 8) % 55)
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return { left, top }
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}
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// Scatter a pet deterministically within roughly ±0.9km of the user, so on a
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// real map markers cluster nearby (stable per pet id across requests).
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function syntheticCoord(id, userLoc) {
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const h = hashId(id)
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const dLat = ((h % 1600) - 800) / 100000 // ±0.008° ≈ ±0.9km
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const dLng = (((h >> 8) % 1600) - 800) / 100000
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return { latitude: userLoc.latitude + dLat, longitude: userLoc.longitude + dLng }
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}
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// Rough distance text from coordinate delta (fallback when no real distance)
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function distanceText(petLoc, userLoc) {
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if (!petLoc || !userLoc) return null
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const R = 6371000
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const dLat = ((petLoc.latitude - userLoc.latitude) * Math.PI) / 180
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const dLon = ((petLoc.longitude - userLoc.longitude) * Math.PI) / 180
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const a =
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Math.sin(dLat / 2) ** 2 +
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Math.cos((userLoc.latitude * Math.PI) / 180) *
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Math.cos((petLoc.latitude * Math.PI) / 180) *
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Math.sin(dLon / 2) ** 2
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const meters = Math.round(R * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a)))
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if (meters < 1000) return `${meters}m`
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return `${(meters / 1000).toFixed(1)}km`
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}
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exports.main = async event => {
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const { OPENID } = cloud.getWXContext()
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const filter = event.filters?.type || 'all'
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const userLoc = event.location || null
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const query = {}
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if (filter === 'dog' || filter === 'cat') query.species = filter
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if (filter === 'online') query.online = true
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let meId = ''
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let followingSet = new Set()
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let followerSet = new Set()
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if (OPENID) {
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const meRes = await db.collection('users').where({ openid: OPENID }).limit(1).get()
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const me = meRes.data[0]
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if (me) {
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meId = me._id
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const [followingRes, followerRes] = await Promise.all([
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db.collection('follows').where({ followerId: meId }).limit(500).get(),
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db.collection('follows').where({ followeeId: meId }).limit(500).get()
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])
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followingSet = new Set(followingRes.data.map(f => f.followeeId))
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followerSet = new Set(followerRes.data.map(f => f.followerId))
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}
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}
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const res = await db.collection('pets').where(query).limit(50).get()
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const ownerIds = [...new Set(res.data.map(pet => pet.ownerId).filter(Boolean))]
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const owners = await fetchUsers(ownerIds)
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const ownerMap = new Map(owners.map(owner => [owner._id, owner]))
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const list = res.data.map(pet => {
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const realCoord = pet.location && typeof pet.location.latitude === 'number' ? pet.location : null
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const coord = realCoord || (userLoc ? syntheticCoord(pet._id, userLoc) : null)
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const owner = ownerMap.get(pet.ownerId)
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const isFollowing = followingSet.has(pet.ownerId)
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const isFollowedBy = followerSet.has(pet.ownerId)
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return {
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...pet,
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ownerName: owner?.nickname || '',
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isMine: Boolean(meId && pet.ownerId === meId),
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isFollowing,
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isFriend: isFollowing && isFollowedBy,
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latitude: coord ? coord.latitude : undefined,
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longitude: coord ? coord.longitude : undefined,
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distanceText: distanceText(coord, userLoc) || pet.distanceText || null,
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pin: stablePin(pet._id)
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}
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})
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return { list }
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}
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