/**
 * Deterministic weighted subscores for an (org, grant) pair — Stage 2 of
 * the scoring engine (docs/plan.md). Pure functions over plain inputs;
 * the match workflow supplies the embedding similarity, everything else
 * derives from columns.
 *
 * `subscores` records each component so weights can be re-tuned from
 * review/booking data without re-deriving inputs.
 *
 *   mission fit       30  embedding cosine similarity, scaled
 *   funder precedent  25  historical giving into the org's state (990-PF)
 *   capacity fit      15  award ceiling vs org revenue (sweet spot 10–75%)
 *   competition       15  state/NH-restricted pools beat national ones
 *   effort            10  LOI/short-form beat full federal
 *   runway             5  3–10 weeks to deadline is ideal
 */

export interface MatchSubscores {
  readonly missionFit: number;
  readonly capacityFit: number;
  readonly competition: number;
  readonly effort: number;
  readonly runway: number;
  readonly funderPrecedent: number;
}

export interface ScoreMatchInput {
  /** Cosine similarity in [-1, 1] between org mission and grant synopsis. */
  readonly similarity: number;
  readonly orgTotalRevenue: number | null;
  readonly awardCeiling: number | null;
  readonly geographicScope: string | null;
  readonly applicationEffortEstimate:
    | 'loi_only'
    | 'short_form'
    | 'full_federal'
    | 'unknown';
  readonly closeDate: Date | null;
  readonly now: Date;
  /**
   * Historical grants this funder has paid to recipients in the org's
   * state (990-PF index for foundations; USASpending PEER award count for
   * federal programs — recipients name-matched to primary-ICP NH orgs).
   * Null = no precedent data — scores 0, not neutral: the plan weights
   * precedent as the strongest single predictor, and absence of evidence
   * should rank below presence.
   */
  readonly funderStateGrantCount: number | null;
  /** Grant source (`grants.source`) — drives the source-aware fit floor. */
  readonly grantSource: string;
}

export const ACHIEVABLE_MAX_SCORE = 100;
/**
 * "Easy win" threshold. With the 990-PF precedent subscore live the scale
 * is the plan's full 0–100; the plan's >=75 easy-win bar applies, plus its
 * precedent floor (see scoreMatch). Thresholds re-tune on review and
 * demo-booking data.
 */
export const EASY_WIN_THRESHOLD = 65;
export const EASY_WIN_MIN_PRECEDENT = 12;

/**
 * Mission-fit floor (federal RFPs only): below 12/30 (≈ cosine 0.57) the
 * match is stored but NOT review-viable — non-mission subscores sum to 50,
 * so without a floor a boys' camp scores 60 on an NIH obesity-research
 * center grant purely on precedent + capacity. Foundation-synthesized
 * grants are exempt: their synopses are generic by construction ("grants
 * for NH nonprofits"), so embedding fit carries no signal there and the
 * precedent evidence IS the case for the match.
 */
export const MISSION_FIT_VIABLE_MIN = 12;
const FIT_FLOOR_SOURCES: ReadonlySet<string> = new Set(['grants_gov']);

/** Similarity below this scores 0 fit; above the ceiling scores full fit. */
const SIMILARITY_FLOOR = 0.45;
const SIMILARITY_CEILING = 0.75;

export function missionFitSubscore(similarity: number): number {
  const clamped = Math.min(
    Math.max(similarity, SIMILARITY_FLOOR),
    SIMILARITY_CEILING,
  );
  return Math.round(
    ((clamped - SIMILARITY_FLOOR) / (SIMILARITY_CEILING - SIMILARITY_FLOOR)) * 30,
  );
}

/**
 * Sweet spot: award is 10–75% of annual revenue (docs/plan.md). A grant
 * dwarfing the org's budget is a capacity red flag to federal funders; a
 * tiny one isn't worth the email. Unknown revenue scores a neutral 7.
 */
export function capacityFitSubscore(
  awardCeiling: number | null,
  orgTotalRevenue: number | null,
): number {
  if (awardCeiling == null || orgTotalRevenue == null || orgTotalRevenue <= 0) {
    return awardCeiling == null ? 0 : 7;
  }
  const ratio = awardCeiling / orgTotalRevenue;
  if (ratio >= 0.1 && ratio <= 0.75) return 15;
  if (ratio >= 0.05 && ratio < 0.1) return 10;
  if (ratio > 0.75 && ratio <= 1.5) return 8;
  if (ratio < 0.05) return 4;
  return 2; // > 150% of revenue: real capacity red flag.
}

const STATE_RESTRICTED_PATTERN =
  /new hampshire|\bnh\b|state of|statewide|county|municipal/i;
const REGIONAL_PATTERN = /new england|northeast|regional/i;

/**
 * Competition proxy until expected-applicant-pool modeling exists:
 * geographically restricted pools are dramatically less competitive than
 * national ones. Null scope (typical for federal) = national = low score.
 */
export function competitionSubscore(geographicScope: string | null): number {
  if (geographicScope == null || geographicScope.trim() === '') return 3;
  if (STATE_RESTRICTED_PATTERN.test(geographicScope)) return 15;
  if (REGIONAL_PATTERN.test(geographicScope)) return 10;
  return 3;
}

export function effortSubscore(
  estimate: ScoreMatchInput['applicationEffortEstimate'],
): number {
  switch (estimate) {
    case 'loi_only':
      return 10;
    case 'short_form':
      return 8;
    case 'unknown':
      return 4;
    case 'full_federal':
      return 2;
  }
}

/**
 * Funder precedent (25): "a foundation that gave to three NH orgs like
 * this one is a near-certain match for a fourth" — the plan's strongest
 * single predictor. v1 measures repeated giving into the org's state;
 * NTEE-level matching arrives when recipient orgs get resolved to EINs.
 */
export function funderPrecedentSubscore(
  funderStateGrantCount: number | null,
): number {
  if (funderStateGrantCount == null || funderStateGrantCount <= 0) return 0;
  if (funderStateGrantCount >= 10) return 25;
  if (funderStateGrantCount >= 5) return 20;
  if (funderStateGrantCount >= 3) return 15;
  return 8;
}

const MS_PER_WEEK = 7 * 24 * 60 * 60 * 1000;

/** 3–10 weeks out is ideal: urgent enough to act on, long enough to apply. */
export function runwaySubscore(closeDate: Date | null, now: Date): number {
  if (closeDate == null) return 2; // rolling/unknown deadline: usable, not urgent.
  const weeks = (closeDate.getTime() - now.getTime()) / MS_PER_WEEK;
  if (weeks < 3) return 0;
  if (weeks <= 10) return 5;
  if (weeks <= 20) return 3;
  return 1;
}

export interface ScoredMatch {
  readonly totalScore: number;
  readonly subscores: MatchSubscores;
  readonly easyWin: boolean;
  /**
   * False when mission fit is below the source-aware floor — the match is
   * recorded (audit trail, re-scoring continuity) but hidden from the
   * pending review queue. The LLM match judge may later override in
   * either direction.
   */
  readonly fitViable: boolean;
}

export function scoreMatch(input: ScoreMatchInput): ScoredMatch {
  const subscores: MatchSubscores = {
    missionFit: missionFitSubscore(input.similarity),
    capacityFit: capacityFitSubscore(input.awardCeiling, input.orgTotalRevenue),
    competition: competitionSubscore(input.geographicScope),
    effort: effortSubscore(input.applicationEffortEstimate),
    runway: runwaySubscore(input.closeDate, input.now),
    funderPrecedent: funderPrecedentSubscore(input.funderStateGrantCount),
  };

  const totalScore =
    subscores.missionFit +
    subscores.capacityFit +
    subscores.competition +
    subscores.effort +
    subscores.runway +
    subscores.funderPrecedent;

  const fitViable =
    !FIT_FLOOR_SOURCES.has(input.grantSource) ||
    subscores.missionFit >= MISSION_FIT_VIABLE_MIN;

  return {
    totalScore,
    subscores,
    easyWin:
      fitViable &&
      totalScore >= EASY_WIN_THRESHOLD &&
      subscores.funderPrecedent >= EASY_WIN_MIN_PRECEDENT,
    fitViable,
  };
}