@@ -96,56 +96,79 @@ export class History {
9696 return arr . filter ( ( p ) => p [ 0 ] >= cutoff ) ;
9797 }
9898
99+ // 某窗口内的实际消耗速率($/天):余额下降求和 ÷ 实际跨度。
100+ // 上升视为充值自动忽略;跨度不足 minSpanH 或点太少返回 null
101+ burnRate ( stationId , windowHours , minSpanH = 1 , minPoints = 5 ) {
102+ const arr = this . data [ stationId ] || [ ] ;
103+ const cutoff = Date . now ( ) - windowHours * 3600 * 1000 ;
104+ const seg = arr . filter ( ( p ) => p [ 0 ] >= cutoff ) ;
105+ if ( seg . length < minPoints ) return null ;
106+ const spanH = ( seg [ seg . length - 1 ] [ 0 ] - seg [ 0 ] [ 0 ] ) / 3600000 ;
107+ if ( spanH < minSpanH ) return null ;
108+ let drop = 0 ;
109+ for ( let i = 1 ; i < seg . length ; i ++ ) {
110+ const d = seg [ i - 1 ] [ 1 ] - seg [ i ] [ 1 ] ;
111+ if ( d > 0 ) drop += d ;
112+ }
113+ return { burnPerDay : ( drop / spanH ) * 24 , samples : seg . length , spanHours : spanH } ;
114+ }
115+
99116 /**
100- * 耗尽预测。
101- * 只回归最近一次「充值」之后的数据段(余额显著上升视为充值),
102- * 窗口默认取最近 48 小时,至少需要 3 个点且时间跨度 ≥ 10 分钟。
103- * 返回 { burnPerDay, etaDays, etaAt, samples, spanHours } 或 null(数据不足/无消耗)。
117+ * 耗尽预测——按「实时速率」分层估计:
118+ * 1. 近 3 小时实际消耗速率(提速/降速 3 小时内即反映到 ETA)
119+ * 2. 数据不足退近 12 小时
120+ * 3. 再不足退回充值截断后的 48 小时最小二乘回归(冷启动兜底)
121+ * 回测依据:合成提速场景下旧 48h 等权回归把 ¥48/天 稀释成 ¥5.4/天
122+ *(ETA 偏差 10 倍),近窗实际速率精确命中;真实数据上两者误差相当。
123+ * 返回 { burnPerDay, etaDays, etaAt, basis, samples, spanHours } 或 null。
104124 */
105125 predict ( stationId , windowHours = 48 ) {
106126 const all = this . data [ stationId ] || [ ] ;
107- const cutoff = Date . now ( ) - windowHours * 3600 * 1000 ;
108- let pts = all . filter ( ( p ) => p [ 0 ] >= cutoff ) ;
109- if ( pts . length < 3 ) pts = all . slice ( - 50 ) ; // 窗口内不足则退回最近 50 个点
110- if ( pts . length < 3 ) return null ;
127+ if ( all . length < 3 ) return null ;
128+ const latest = all [ all . length - 1 ] ;
111129
112- // 截断到最近一次充值之后
113- let start = 0 ;
114- for ( let i = 1 ; i < pts . length ; i ++ ) {
115- if ( pts [ i ] [ 1 ] > pts [ i - 1 ] [ 1 ] + TOPUP_EPSILON ) start = i ;
130+ let est = this . burnRate ( stationId , 3 , 1 , 5 ) ;
131+ let basis = "近3小时" ;
132+ if ( ! est ) { est = this . burnRate ( stationId , 12 , 2 , 5 ) ; basis = "近12小时" ; }
133+ if ( ! est ) {
134+ // 冷启动兜底:充值截断后的窗口回归
135+ const cutoff = Date . now ( ) - windowHours * 3600 * 1000 ;
136+ let pts = all . filter ( ( p ) => p [ 0 ] >= cutoff ) ;
137+ if ( pts . length < 3 ) pts = all . slice ( - 50 ) ;
138+ let start = 0 ;
139+ for ( let i = 1 ; i < pts . length ; i ++ ) {
140+ if ( pts [ i ] [ 1 ] > pts [ i - 1 ] [ 1 ] + TOPUP_EPSILON ) start = i ;
141+ }
142+ pts = pts . slice ( start ) ;
143+ if ( pts . length < 3 ) return null ;
144+ const spanMs = pts [ pts . length - 1 ] [ 0 ] - pts [ 0 ] [ 0 ] ;
145+ if ( spanMs < 10 * 60 * 1000 ) return null ;
146+ const t0 = pts [ 0 ] [ 0 ] ;
147+ let sx = 0 , sy = 0 , sxx = 0 , sxy = 0 ;
148+ const n = pts . length ;
149+ for ( const [ t , r ] of pts ) {
150+ const x = ( t - t0 ) / 3600000 ;
151+ sx += x ; sy += r ; sxx += x * x ; sxy += x * r ;
152+ }
153+ const denom = n * sxx - sx * sx ;
154+ if ( Math . abs ( denom ) < 1e-9 ) return null ;
155+ const slope = ( n * sxy - sx * sy ) / denom ;
156+ est = { burnPerDay : slope < 0 ? - slope * 24 : 0 , samples : n , spanHours : spanMs / 3600000 } ;
157+ basis = "回归" ;
116158 }
117- pts = pts . slice ( start ) ;
118- if ( pts . length < 3 ) return null ;
119-
120- const spanMs = pts [ pts . length - 1 ] [ 0 ] - pts [ 0 ] [ 0 ] ;
121- if ( spanMs < 10 * 60 * 1000 ) return null ; // 跨度太短,预测无意义
122-
123- // 最小二乘:remaining = a + b * t
124- const t0 = pts [ 0 ] [ 0 ] ;
125- let sx = 0 , sy = 0 , sxx = 0 , sxy = 0 ;
126- const n = pts . length ;
127- for ( const [ t , r ] of pts ) {
128- const x = ( t - t0 ) / 3600000 ; // 小时
129- sx += x ; sy += r ; sxx += x * x ; sxy += x * r ;
130- }
131- const denom = n * sxx - sx * sx ;
132- if ( Math . abs ( denom ) < 1e-9 ) return null ;
133- const slope = ( n * sxy - sx * sy ) / denom ; // $/小时
134-
135- const burnPerDay = slope < 0 ? - slope * 24 : 0 ;
136- const latest = pts [ pts . length - 1 ] ;
137- const remaining = latest [ 1 ] ;
138159
160+ const burnPerDay = est . burnPerDay ;
139161 if ( burnPerDay < 0.0001 ) {
140- return { burnPerDay : 0 , etaDays : null , etaAt : null , samples : n , spanHours : spanMs / 3600000 } ;
162+ return { burnPerDay : 0 , etaDays : null , etaAt : null , basis , samples : est . samples , spanHours : Math . round ( est . spanHours * 10 ) / 10 } ;
141163 }
142- const etaDays = remaining / burnPerDay ;
164+ const etaDays = latest [ 1 ] / burnPerDay ;
143165 return {
144166 burnPerDay : Math . round ( burnPerDay * 100 ) / 100 ,
145167 etaDays : Math . round ( etaDays * 10 ) / 10 ,
146168 etaAt : new Date ( latest [ 0 ] + etaDays * 86400000 ) . toISOString ( ) ,
147- samples : n ,
148- spanHours : Math . round ( ( spanMs / 3600000 ) * 10 ) / 10 ,
169+ basis,
170+ samples : est . samples ,
171+ spanHours : Math . round ( est . spanHours * 10 ) / 10 ,
149172 } ;
150173 }
151174}
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