// Investor Flow — Confluence Rack (M22, slice 2)
//
// The aggregator that turns per-slot firing states into a redundancy-aware
// "picture quality" assessment for a symbol. It:
//   • buckets fired slots into bullish vs bearish evidence (exit slots count as
//     bear evidence),
//   • applies redundancy-group discounting so correlated slots are not
//     triple-counted,
//   • labels the overall picture with an evidence-based quality tier,
//   • detects picture *changes* between consecutive evaluations for the
//     confluence-change alert producer.
//
// Pure: consumes slot assessments, emits a labeled evaluation. NO I/O.
// ADR-0007: the output is a description of the picture ("strong-bullish",
// "mixed") — evidence, never a directive to buy or sell.

import { CONFLUENCE_SLOTS, type ConfluenceSlot } from './confluenceSlots.ts';
import { groupWeight, redundancyGroupFor } from './confluenceLibrary.ts';

/** Per-slot assessment fed into a rack evaluation. */
export interface SlotAssessment {
  id: string;
  /** fired = the slot's evidence is present; not-fired = data seen, evidence absent. */
  state: 'fired' | 'not-fired';
  /** Optional 0..1 confidence of the evaluation itself. */
  confidence?: number;
  /** Optional free-text note for explain output. */
  note?: string;
}

/** A symbol's confluence evaluation for one as-of timestamp. */
export interface ConfluenceEvaluation {
  symbol: string;
  /** ISO date (YYYY-MM-DD) the evaluation is for. */
  asOf: string;
  assessments: SlotAssessment[];
  /** Redundancy-discounted bullish evidence weight. */
  bullEvidence: number;
  /** Redundancy-discounted bearish (bear + exit) evidence weight. */
  bearEvidence: number;
  /** Raw counts (before redundancy discounting). */
  bullCount: number;
  bearCount: number;
  /** Slots assessed (with data); sheds light on coverage. */
  assessedCount: number;
  /** Net bullish evidence (bull - bear). Positive = more bullish evidence. */
  netEvidence: number;
  /** Total recognized evidence (bull + bear). */
  totalEvidence: number;
  /** Evidence-based picture label. */
  quality: PictureQuality;
}

/** Evidence-based picture labels, ordered from most to least constructive. */
export type PictureQuality =
  | 'strong-bullish'
  | 'moderate-bullish'
  | 'weak-bullish'
  | 'mixed'
  | 'weak-bearish'
  | 'moderate-bearish'
  | 'strong-bearish'
  | 'sparse';

/** Ordering for change detection / tier comparison. */
export const QUALITY_RANK: Record<PictureQuality, number> = {
  'strong-bullish': 7,
  'moderate-bullish': 6,
  'weak-bullish': 5,
  'mixed': 4,
  'weak-bearish': 3,
  'moderate-bearish': 2,
  'strong-bearish': 1,
  'sparse': 0,
};

/** Minimum total evidence before the picture is meaningful rather than 'sparse'. */
export const MIN_TOTAL_EVIDENCE = 1.0;
/** Evidence ratio that separates "bullish/bearish" from "mixed". */
export const DIRECTION_RATIO = 0.6;
/** Total evidence marking a "strong" vs "moderate" picture. */
export const STRONG_EVIDENCE = 4.0;
/** Total evidence marking a "moderate" vs "weak" picture. */
export const MODERATE_EVIDENCE = 2.0;

/** Which side a slot's firing evidence serves. */
export function slotBody(slot: ConfluenceSlot): 'bull' | 'bear' {
  return slot.body === 'exit' ? 'bear' : slot.body;
}

/** Is `id` a known slot? */
function isKnownSlot(id: string): boolean {
  return CONFLUENCE_SLOTS.some((s) => s.id === id);
}

/**
 * Evaluate a rack: bucket the fired assessments into bull/bear evidence,
 * discount per redundancy group, and label the picture.
 */
export function evaluateRack(
  symbol: string,
  asOf: string,
  assessments: SlotAssessment[],
): ConfluenceEvaluation {
  const slotById = new Map(CONFLUENCE_SLOTS.map((s) => [s.id, s]));

  const firedBull: string[] = [];
  const firedBear: string[] = [];
  let assessedCount = 0;

  for (const a of assessments) {
    if (!isKnownSlot(a.id)) continue;
    assessedCount += 1;
    if (a.state !== 'fired') continue;
    const body = slotBody(slotById.get(a.id)!);
    if (body === 'bull') firedBull.push(a.id);
    else firedBear.push(a.id);
  }

  // Group fired slots by redundancy group; ungrouped slots get singleton buckets.
  const bucket = (id: string): string => {
    const g = redundancyGroupFor(id);
    return g ? `g:${g.slots.join(',')}` : `solo:${id}`;
  };

  const bullGroups = new Map<string, string[]>();
  const bearGroups = new Map<string, string[]>();
  for (const id of firedBull) {
    const key = bucket(id);
    const arr = bullGroups.get(key) ?? [];
    arr.push(id);
    bullGroups.set(key, arr);
  }
  for (const id of firedBear) {
    const key = bucket(id);
    const arr = bearGroups.get(key) ?? [];
    arr.push(id);
    bearGroups.set(key, arr);
  }

  let bullEvidence = 0;
  for (const ids of bullGroups.values()) bullEvidence += groupWeight(ids);
  let bearEvidence = 0;
  for (const ids of bearGroups.values()) bearEvidence += groupWeight(ids);

  const netEvidence = bullEvidence - bearEvidence;
  const totalEvidence = bullEvidence + bearEvidence;
  const quality = labelQuality(bullEvidence, bearEvidence, totalEvidence);

  return {
    symbol,
    asOf,
    assessments,
    bullEvidence,
    bearEvidence,
    bullCount: firedBull.length,
    bearCount: firedBear.length,
    assessedCount,
    netEvidence,
    totalEvidence,
    quality,
  };
}

/** Label the picture from the discounted evidence totals. Pure. */
export function labelQuality(bullEvidence: number, bearEvidence: number, totalEvidence: number): PictureQuality {
  if (totalEvidence < MIN_TOTAL_EVIDENCE) return 'sparse';

  const ratio = bullEvidence / totalEvidence;
  if (ratio >= DIRECTION_RATIO) return magnitudeLabel(bullEvidence, 'bullish');
  if (ratio <= 1 - DIRECTION_RATIO) return magnitudeLabel(bearEvidence, 'bearish');
  return 'mixed';
}

function magnitudeLabel(strongSideEvidence: number, side: 'bullish' | 'bearish'): PictureQuality {
  if (strongSideEvidence >= STRONG_EVIDENCE) return side === 'bullish' ? 'strong-bullish' : 'strong-bearish';
  if (strongSideEvidence >= MODERATE_EVIDENCE) return side === 'bullish' ? 'moderate-bullish' : 'moderate-bearish';
  return side === 'bullish' ? 'weak-bullish' : 'weak-bearish';
}

/** A detected change between two evaluations. */
export interface ConfluenceChange {
  changed: boolean;
  /** Direction of the picture change from the consumer's perspective. */
  changeType: 'improved' | 'deteriorated' | 'unchanged';
  current: PictureQuality;
  previous: PictureQuality | null;
  netEvidenceShift: number;
  /** Slot ids whose firing state flipped between the two evaluations. */
  flippedSlotIds: string[];
}

/** Minimum net-evidence shift that counts as a *noteworthy* change. */
export const MIN_CHANGE_SHIFT = 0.35;

/**
 * Detect whether the picture changed meaningfully between two consecutive
 * evaluations of the same symbol. Used by the confluence-change alert producer.
 * Pure.
 */
export function detectPictureChange(
  previous: ConfluenceEvaluation | null,
  current: ConfluenceEvaluation,
): ConfluenceChange {
  if (previous === null) {
    return { changed: false, changeType: 'unchanged', current: current.quality, previous: null, netEvidenceShift: 0, flippedSlotIds: [] };
  }

  const flippedSlotIds = flippedSlots(previous.assessments, current.assessments);
  const netEvidenceShift = current.netEvidence - previous.netEvidence;

  const rankShift = QUALITY_RANK[current.quality] - QUALITY_RANK[previous.quality];
  if (rankShift > 0 || (rankShift === 0 && netEvidenceShift >= MIN_CHANGE_SHIFT)) {
    return { changed: true, changeType: 'improved', current: current.quality, previous: previous.quality, netEvidenceShift, flippedSlotIds };
  }
  if (rankShift < 0 || (rankShift === 0 && netEvidenceShift <= -MIN_CHANGE_SHIFT)) {
    return { changed: true, changeType: 'deteriorated', current: current.quality, previous: previous.quality, netEvidenceShift, flippedSlotIds };
  }
  return { changed: false, changeType: 'unchanged', current: current.quality, previous: previous.quality, netEvidenceShift, flippedSlotIds };
}

/** Fired-state flips between two assessment sets. Pure. */
export function flippedSlots(prev: SlotAssessment[], curr: SlotAssessment[]): string[] {
  const prevMap = new Map(prev.map((a) => [a.id, a.state]));
  const currMap = new Map(curr.map((a) => [a.id, a.state]));
  const flipped: string[] = [];
  for (const id of prevMap.keys()) {
    if (currMap.has(id) && prevMap.get(id) !== currMap.get(id)) flipped.push(id);
  }
  for (const id of currMap.keys()) {
    if (!prevMap.has(id)) flipped.push(id);
  }
  return flipped;
}

/** Marker re-export so the module documents the exit→bear convention. */
export { isBearEvidence } from './confluenceSlots.ts';