import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";

/** The three immutable share envelopes accepted by the main conversation. */
export type ShareKind = "single" | "all" | "refined";
export type ShareTarget = Readonly<{ question: string; answer: string; entryId?: string; attemptId?: string }>;
export type ShareDraft = Readonly<{ kind: ShareKind; header: string; targets: readonly ShareTarget[]; body: string }>;

const headers: Record<ShareKind, string> = {
  single: "[/btw note: the user asked this as a side question and chose to share the answer with you]",
  all: "[/btw note: the user asked these side questions and chose to share the answers with you]",
  refined: "[/btw note: the user asked a side question and chose to share a refined summary with you]",
};

export function createShareDraft(kind: "single", target: ShareTarget): ShareDraft;
export function createShareDraft(kind: "all", targets: readonly ShareTarget[]): ShareDraft;
export function createShareDraft(kind: "refined", body: string, target?: ShareTarget): ShareDraft;
export function createShareDraft(kind: ShareKind, value: ShareTarget | readonly ShareTarget[] | string, target?: ShareTarget): ShareDraft {
  const supplied = kind === "refined" ? (target ? [target] : []) : (Array.isArray(value) ? value : [value as ShareTarget]);
  const targets = supplied.map((item) => Object.freeze({ ...item }));
  const body = kind === "refined"
    ? String(value).trim()
    : targets.map(({ question, answer }) => `Q: ${question}\nA: ${answer}`).join("\n\n");
  return Object.freeze({ kind, header: headers[kind], targets: Object.freeze(targets), body });
}

export const shareHeader = (kind: ShareKind): string => headers[kind];
export const singleShareDraft = (target: ShareTarget): ShareDraft => createShareDraft("single", target);
export const allShareDraft = (targets: readonly ShareTarget[]): ShareDraft => createShareDraft("all", targets);
export const refinedShareDraft = (body: string, target?: ShareTarget): ShareDraft => createShareDraft("refined", body, target);
export const renderShareDraft = (draft: ShareDraft): string => `${draft.header}\n${draft.body}`;

/** The self-describing note appended to the main conversation when one answer is shared. */
export function buildPromoteNote(question: string, answer: string): string {
  return renderShareDraft(createShareDraft("single", { question, answer }));
}

/** Whole-thread variant: every shared Q/A of the thread in one note. */
export function buildMultiPromoteNote(pairs: { question: string; answer: string }[]): string {
  return renderShareDraft(createShareDraft("all", pairs));
}

/** Refined variant: a shadow-pass rewrite of the Q/A instead of the raw text. */
export function buildRefinedPromoteNote(summary: string): string {
  return renderShareDraft(createShareDraft("refined", summary));
}

/** Queue the note as one user-visible message to the main session. */
export function sendPromote(pi: ExtensionAPI, note: string): void {
  pi.sendMessage(
    { customType: "btw-promote", content: note, display: true },
    { triggerTurn: false, deliverAs: "nextTurn" },
  );
}