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ee888e1 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 | // @ts-check
/**
* EMA-based threat velocity engine for conflict data.
* Pure functions — no Redis, no side effects.
*/
const ALPHA = 0.3;
const MIN_WINDOW = 6; // min points before z-score is meaningful
/**
* @typedef {{ region: string, window: number[], ema: number, mean: number, stddev: number, updatedAt: number }} WindowState
*/
/**
* @param {string} region
* @param {number} count
* @param {WindowState|null} prior - prior WindowState or null
* @returns {WindowState}
*/
export function updateWindow(region, count, prior) {
const prevWindow = Array.isArray(prior?.window) ? prior.window : [];
const window = [...prevWindow, count].slice(-24);
const prevEma = typeof prior?.ema === 'number' ? prior.ema : count;
const ema = ALPHA * count + (1 - ALPHA) * prevEma;
const { mean, stddev } = computeWindowStats(window);
return { region, window, ema, mean, stddev, updatedAt: Date.now() };
}
/** @param {string|undefined} name @returns {string} */
function normalizeCountry(name) {
return (name ?? '').trim().toLowerCase();
}
/**
* @param {number[]} window
* @returns {{ mean: number, stddev: number }}
*/
export function computeWindowStats(window) {
if (window.length === 0) return { mean: 0, stddev: 0 };
const mean = window.reduce((s, v) => s + v, 0) / window.length;
const variance = window.reduce((s, v) => s + (v - mean) ** 2, 0) / window.length;
const stddev = Math.sqrt(variance);
return { mean, stddev };
}
/**
* @param {Map<string,any>} priorWindows
* @param {any[]} acledEvents — each has event_date: 'YYYY-MM-DD'
* @param {any[]} ucdpEvents — each has date_start: 'YYYY-MM-DD' and country/country_name
* @param {number} [nowMs]
* @returns {Map<string, WindowState>}
*/
export function computeEmaWindows(priorWindows, acledEvents, ucdpEvents, nowMs = Date.now()) {
const cutoff = nowMs - 24 * 60 * 60 * 1000;
/** @type {Map<string, number>} */
const counts24h = new Map();
const safeAcled = Array.isArray(acledEvents) ? acledEvents : [];
const safeUcdp = Array.isArray(ucdpEvents) ? ucdpEvents : [];
for (const ev of safeAcled) {
const country = normalizeCountry(ev?.country);
if (!country) continue;
const ts = Date.parse(ev.event_date);
if (Number.isFinite(ts) && ts >= cutoff) {
counts24h.set(country, (counts24h.get(country) ?? 0) + 1);
}
}
for (const ev of safeUcdp) {
const country = normalizeCountry(ev?.country ?? ev?.country_name);
if (!country) continue;
const ts = Date.parse(ev.date_start);
if (Number.isFinite(ts) && ts >= cutoff) {
counts24h.set(country, (counts24h.get(country) ?? 0) + 1);
}
}
const safePrior = priorWindows instanceof Map ? priorWindows : new Map();
const allCountries = new Set([...safePrior.keys(), ...counts24h.keys()]);
/** @type {Map<string, WindowState>} */
const updated = new Map();
for (const country of allCountries) {
const count = counts24h.get(country) ?? 0;
const prior = safePrior.get(country) ?? null;
const ws = updateWindow(country, count, prior);
updated.set(country, ws);
}
return updated;
}
/**
* @param {Map<string, WindowState>} windows
* @returns {Map<string, { risk24h: number, zscore: number, velocitySpike: boolean, region: string }>}
*/
export function computeRisk24h(windows) {
/** @type {Map<string, { risk24h: number, zscore: number, velocitySpike: boolean, region: string }>} */
const result = new Map();
for (const [country, state] of windows) {
if (state.window.length < MIN_WINDOW) {
result.set(country, { risk24h: 0, zscore: 0, velocitySpike: false, region: country });
continue;
}
const zscore = state.stddev > 0 ? (state.ema - state.mean) / state.stddev : 0;
const risk24h = Math.min(100, Math.max(0, Math.round(50 + zscore * 20)));
const velocitySpike = risk24h >= 75;
result.set(country, { risk24h, zscore, velocitySpike, region: country });
}
return result;
}
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