import type { ActivitySummary } from "@/types/form";

/**
 * CiviCRM activity stage values → Framework Stage rank (1..5). "Inquiry"
 * predates Stage 1 and is conventionally rank 0 (pre-engagement); callers
 * that render stage lanes 1..5 should treat 0 as "no rank in scope".
 */
export const STAGE_RANK: Record<string, number> = {
  Inquiry: 0,
  Organizing: 1,
  Feasibility: 2,
  "Business feasibility": 3,
  "Store Implementation": 4,
  "Stabilize newly opened co-op": 5,
};

/**
 * Build a resolver that returns the co-op's Framework Stage rank at a given
 * point in time, derived from the activity stream. Only activities that
 * carry a non-empty `stage` value are stage transitions; their stage holds
 * from that activity's date forward until the next transition.
 *
 * Returns `null` when the date precedes any known transition (i.e. we have
 * no evidence of which stage the co-op was in at that point) — callers can
 * fall back to a field-section default in that case.
 */
export function buildStageRankAtDate(
  activities: ActivitySummary[]
): (isoDate: string) => number | null {
  const transitions = activities
    .filter(
      (a): a is ActivitySummary & { stage: string } =>
        typeof a.stage === "string" && a.stage.length > 0
    )
    .map((a) => ({ t: new Date(a.date).getTime(), stage: a.stage }))
    .filter((tr) => Number.isFinite(tr.t))
    .sort((a, b) => a.t - b.t);

  return (isoDate: string) => {
    const t = new Date(isoDate).getTime();
    if (!Number.isFinite(t)) return null;
    let last: number | null = null;
    for (const tr of transitions) {
      if (tr.t > t) break;
      const r = STAGE_RANK[tr.stage];
      if (typeof r === "number") last = r;
    }
    return last;
  };
}