import { NEWSLETTER_KIND, NEWSLETTER_TAG } from '@/lib/types';

/**
 * The subset of a static newsletter issue we need to turn it into a NIP-23
 * long-form article (kind 30023). Kept structural (not importing the page) to
 * avoid a page → lib → page import cycle.
 */
export interface StaticIssueLike {
  number: number;
  date: string; // ISO "YYYY-MM-DD"
  vibe: string;
  updates: { title: string; tag: string; body: string }[];
  spotOfTheWeek?: {
    title: string;
    location: string;
    why: string;
    mapperName?: string;
    image?: string;
    href?: string;
  };
  communityNote: string;
}

/** Stable addressable identifier for a backfilled archive issue. */
export function issueSlug(number: number): string {
  return `issue-${number}`;
}

/** Human title for an issue, e.g. "SkateSpots Drop #005". */
export function issueTitle(number: number): string {
  return `SkateSpots Drop #${String(number).padStart(3, '0')}`;
}

/** Render a static issue's structured sections into a Markdown article body. */
export function issueToMarkdown(issue: StaticIssueLike): string {
  const lines: string[] = [];

  lines.push(`_${issue.vibe}_`);
  lines.push('');

  lines.push('## What shipped');
  lines.push('');
  for (const u of issue.updates) {
    lines.push(`### ${u.title}`);
    lines.push(`**${u.tag}**`);
    lines.push('');
    lines.push(u.body);
    lines.push('');
  }

  if (issue.spotOfTheWeek) {
    const s = issue.spotOfTheWeek;
    lines.push('## Spot of the Week');
    lines.push('');
    lines.push(`**${s.title}** — ${s.location}`);
    lines.push('');
    lines.push(s.why);
    if (s.mapperName) {
      lines.push('');
      lines.push(`_Mapped by ${s.mapperName}_`);
    }
    lines.push('');
  }

  lines.push('## Community');
  lines.push('');
  lines.push(issue.communityNote);
  lines.push('');
  lines.push('---');
  lines.push('');
  lines.push('Read every drop at https://skate-spots.org/#/newsletter');

  return lines.join('\n');
}

/** A one-line summary for the article's NIP-23 `summary` tag. */
export function issueSummary(issue: StaticIssueLike): string {
  return issue.vibe.length > 180 ? `${issue.vibe.slice(0, 177)}…` : issue.vibe;
}

/** Build the full (unsigned) kind-30023 event template for a static issue. */
export function buildIssueArticle(issue: StaticIssueLike) {
  const publishedAt = Math.floor(new Date(issue.date + 'T12:00:00Z').getTime() / 1000);
  const image = issue.spotOfTheWeek?.image;
  return {
    kind: NEWSLETTER_KIND,
    content: issueToMarkdown(issue),
    tags: [
      ['d', issueSlug(issue.number)],
      ['title', issueTitle(issue.number)],
      ['summary', issueSummary(issue)],
      ...(image ? [['image', image]] : []),
      ['published_at', String(Number.isFinite(publishedAt) ? publishedAt : Math.floor(Date.now() / 1000))],
      ['t', NEWSLETTER_TAG],
      ['t', 'skatespots'],
      ['t', 'newsletter'],
      ['t', 'skateboarding'],
      ['alt', `SkateSpots newsletter issue: ${issueTitle(issue.number)}`],
    ] as string[][],
  };
}