99 lines
2.9 KiB
Swift
99 lines
2.9 KiB
Swift
//
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// HeuristicRanker.swift
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// iris
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//
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// Created by Codex.
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//
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import Foundation
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struct UserContext: Equatable {
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var isMoving: Bool
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var city: String
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init(isMoving: Bool, city: String = "London") {
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self.isMoving = isMoving
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self.city = city
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}
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}
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final class HeuristicRanker {
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private let nowProvider: () -> Int
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private let lastShownAtProvider: (String) -> Int?
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init(now: @escaping () -> Int = { Int(Date().timeIntervalSince1970) },
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lastShownAt: @escaping (String) -> Int? = { _ in nil }) {
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self.nowProvider = now
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self.lastShownAtProvider = lastShownAt
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}
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struct Ranked: Equatable {
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let item: FeedItem
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let confidence: Double
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let isEligibleForRightNow: Bool
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}
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struct WinnerSelection: Equatable {
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let item: FeedItem
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let priority: Double
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}
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func pickWinner(from items: [Ranked], now: Int? = nil, context: UserContext) -> WinnerSelection? {
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let currentTime = now ?? nowProvider()
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let valid = items
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.filter { $0.item.ttlSec > 0 }
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.filter { $0.confidence >= 0.0 }
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.filter { $0.isEligibleForRightNow }
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guard !valid.isEmpty else { return nil }
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var best: (item: FeedItem, score: Double, confidence: Double)?
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for proposed in valid {
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let baseWeight = baseWeight(for: proposed.item.type)
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var score = baseWeight * min(max(proposed.confidence, 0.0), 1.0)
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if let shownAt = lastShownAtProvider(proposed.item.id),
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currentTime - shownAt <= 2 * 60 * 60 {
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score -= 0.4
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}
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if best == nil || score > best!.score {
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best = (proposed.item, score, proposed.confidence)
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}
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}
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guard let best else {
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return nil
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}
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let priority = min(max(best.score, 0.0), 1.0)
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let item = FeedItem(
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id: best.item.id,
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type: best.item.type,
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title: best.item.title.truncated(maxLength: TextConstraints.titleMax),
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subtitle: best.item.subtitle.truncated(maxLength: TextConstraints.subtitleMax),
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priority: priority,
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ttlSec: max(1, best.item.ttlSec),
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condition: best.item.condition,
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startsAt: best.item.startsAt,
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poiType: best.item.poiType,
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bucket: .rightNow,
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actions: ["DISMISS"]
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)
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return WinnerSelection(item: item, priority: priority)
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}
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private func baseWeight(for type: FeedItemType) -> Double {
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switch type {
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case .weatherWarning: return 1.0
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case .weatherAlert: return 0.9
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case .calendarEvent: return 0.8
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case .transit: return 0.75
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case .poiNearby: return 0.6
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case .info: return 0.4
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case .nowPlaying: return 0.25
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case .currentWeather: return 0.0
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case .allQuiet: return 0.0
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}
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}
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}
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