import {
  LNURL_SLUG_PREFIX, fedimintKey, fedimintSlug, lnurlIdentifier, lnurlKey, normalizeMintUrl,
  type FedimintAnnouncement, type FedimintFields, type LnurlAnnouncement, type LnurlFields,
} from '@cashumints/shared';
import { getDb } from './db.ts';
import { log } from './log.ts';

/**
 * URLs already reported as unusable. A rejected value (an onion address, a bare label)
 * recurs in dozens of events per cycle, and logging each occurrence buries the lines
 * that matter.
 *
 * Fedimint invite codes used to be the loudest entry in here, arriving as `u` tags this
 * function could make no sense of. They have their own path now and never reach it.
 */
const reportedSkips = new Set<string>();

export interface MintRow {
  url: string;
  host: string;
  /** 'cashu', 'fedimint' or 'lnurl'. Rows written before the column existed default to 'cashu'. */
  type: string;
  name: string | null;
  description: string | null;
  icon_url: string | null;
  icon_file: string | null;
  pubkey: string | null;
  info_json: string | null;
  /**
   * Type-specific data: `FedimintFields` for a federation, `LnurlFields` for an LNURL
   * mint, null for a Cashu one. Read it back through `parseEcosystem`.
   */
  ecosystem_json: string | null;
  nuts_json: string | null;
  version: string | null;
  status: string;
  consecutive_fails: number;
  last_online: number | null;
  last_probe: number | null;
  first_seen: number;
  updated_at: number;
}

/**
 * Insert a mint if it is new. Never touches an existing row: cached metadata is the
 * whole point of the table, and discovery must not overwrite what a probe learned.
 * Returns the normalized URL when a row was created, null otherwise.
 *
 * Deduped on the slug, not the URL. Real data has `https://mint.minibits.cash/Bitcoin`
 * and `https://mint.minibits.cash/bitcoin` announced as separate mints; they are one
 * mint written two ways, and keying on the URL would split its reviews across two pages.
 * The URL keeps its original path case, because a mint's path is case sensitive over
 * HTTP and the lowercase spelling 404s when probed.
 *
 * ponytail: whichever casing is seen first wins and is the one probed. The seed list
 * pins the working spelling, so in practice the correct one is always inserted first.
 * If that ever stops holding, the upgrade is to probe both casings once and keep the
 * one that answers.
 */
export async function insertMintIfNew(
  rawUrl: string,
  now = Math.floor(Date.now() / 1000),
): Promise<string | null> {
  const normalized = normalizeMintUrl(rawUrl);
  if (!normalized) {
    if (!reportedSkips.has(rawUrl)) {
      reportedSkips.add(rawUrl);
      log.warn('skipped mint url', { url: rawUrl.slice(0, 80) });
    }
    return null;
  }

  const db = await getDb();
  // No conflict target, so this covers both unique keys — url and host — in one clause.
  // (`INSERT OR IGNORE` would too, but only SQLite knows that spelling.)
  const result = await db.run(
    `INSERT INTO mints (url, host, type, status, first_seen, updated_at)
     VALUES (?, ?, 'cashu', 'unknown', ?, ?)
     ON CONFLICT DO NOTHING`,
    normalized.url,
    normalized.host,
    now,
    now,
  );

  if (result.changes > 0) return normalized.url;

  /*
   * The no-op insert is almost always this exact URL already being tracked. The other
   * possibility is a *different* URL whose slug collides (`host/a-b` vs `host/a/b`
   * both slug to `host-a-b`): that mint is silently not tracked and any review of it
   * files under the other one, which is worth a log line the first time it happens.
   */
  const holder = await db.get<{ url: string }>(
    'SELECT url FROM mints WHERE host = ?',
    normalized.host,
  );
  if (holder && holder.url !== normalized.url && !reportedSkips.has(normalized.url)) {
    reportedSkips.add(normalized.url);
    log.warn('slug collision, mint not tracked', {
      url: normalized.url,
      host: normalized.host,
      existing: holder.url,
    });
  }

  return null;
}

/* ---------- fedimint ---------- */

/**
 * Read a row's type-specific column back out.
 *
 * Generic, defaulting to `FedimintFields` so every existing call site reads exactly as
 * it did. The caller already knows the row's `type` — it is what decided to call this
 * at all — so the type argument is a statement of what was stored, not a guess.
 *
 * A column that will not parse degrades to null rather than throwing. Such a row still
 * has a page and still resolves by its key; it simply has no ecosystem-specific fields
 * on it, which is honest and is better than a probe cycle dying on one bad row.
 */
export function parseEcosystem<T = FedimintFields>(
  row: Pick<MintRow, 'ecosystem_json'>,
): T | null {
  if (!row.ecosystem_json) return null;
  try {
    return JSON.parse(row.ecosystem_json) as T;
  } catch {
    return null;
  }
}

/**
 * Insert or refresh a federation from a kind 38173 announcement.
 *
 * Deduped on the federation id, which is the only identity a federation has: the same
 * federation is announced by several people (two different npubs currently announce
 * "Bitcoin Principles" with the same `d`), and every one of those is the same thing to
 * join. One row, keyed on the id, whoever published it.
 *
 * Unlike `insertMintIfNew` this does update an existing row, and it has to: an
 * announcement is the *only* source of a federation's invite codes, modules and name,
 * where a Cashu mint's row is refreshed by probing the mint itself. Older announcements
 * are ignored (`announced_at` goes forwards only) so a replayed event from last year
 * cannot overwrite this week's invite code.
 *
 * The status columns are never touched here. Whether a federation is up is a probe's
 * answer, and an announcement is not evidence of anything being up.
 *
 * Returns the row's key when a row was created, null when one was merely updated.
 */
export async function upsertFedimint(
  announcement: FedimintAnnouncement,
  now = Math.floor(Date.now() / 1000),
): Promise<string | null> {
  const db = await getDb();
  const url = fedimintKey(announcement.federationId);
  const host = fedimintSlug(announcement.federationId);

  const fields: FedimintFields = {
    federation_id: announcement.federationId,
    invite_codes: announcement.inviteCodes,
    modules: announcement.modules,
    network: announcement.network,
    announced_at: announcement.announcedAt,
    announcer_pubkey: announcement.announcerPubkey,
    // Set by the probe, not by an announcement. Carried over below when a row exists.
    status_source: null,
  };

  const existing = await db.get<MintRow>('SELECT * FROM mints WHERE url = ?', url);

  if (!existing) {
    await db.run(
      `INSERT INTO mints (url, host, type, name, description, icon_url, ecosystem_json,
                          status, first_seen, updated_at)
       VALUES (?, ?, 'fedimint', ?, ?, ?, ?, 'announced', ?, ?)
       ON CONFLICT DO NOTHING`,
      url,
      host,
      announcement.name,
      announcement.about,
      announcement.picture,
      JSON.stringify(fields),
      now,
      now,
    );
    return url;
  }

  const previous = parseEcosystem(existing);
  if (previous && (previous.announced_at ?? 0) > announcement.announcedAt) return null;

  await db.run(
    `UPDATE mints SET
       name = COALESCE(?, name),
       description = COALESCE(?, description),
       icon_url = COALESCE(?, icon_url),
       ecosystem_json = ?,
       updated_at = ?
     WHERE url = ?`,
    announcement.name,
    announcement.about,
    announcement.picture,
    JSON.stringify({ ...fields, status_source: previous?.status_source ?? null }),
    now,
    url,
  );

  return null;
}

/**
 * Insert a federation from an invite code alone, with no announcement behind it.
 *
 * For `POST /api/index`: a reader pastes the one thing they have, and there is nothing
 * else to go on. The id comes out of the code itself (`federationIdFromInviteCode`), so
 * the row is keyed exactly as an announced one would be and the two can never become
 * two rows for one federation.
 *
 * `announced` rather than `unknown`, and the distinction is the same one the status
 * carries everywhere else: `unknown` means nothing has checked yet, `announced` means
 * there is nothing this site *can* check. A federation has no public endpoint, so an
 * invite code is exactly as much as anyone will ever be able to confirm from here until
 * the observer lookup covers it.
 *
 * Returns the row key when a row was created, null when one already existed.
 */
export async function insertFedimintFromInvite(
  code: string,
  federationId: string,
  now = Math.floor(Date.now() / 1000),
): Promise<string | null> {
  const db = await getDb();
  const url = fedimintKey(federationId);

  const fields: FedimintFields = {
    federation_id: federationId,
    invite_codes: [code.trim().toLowerCase()],
    // Everything an announcement would have carried. Discovery fills these in when one
    // turns up, and until then the page says only what the code itself proves.
    modules: [],
    network: null,
    announced_at: null,
    announcer_pubkey: null,
    status_source: null,
  };

  const result = await db.run(
    `INSERT INTO mints (url, host, type, ecosystem_json, status, first_seen, updated_at)
     VALUES (?, ?, 'fedimint', ?, 'announced', ?, ?)
     ON CONFLICT DO NOTHING`,
    url,
    fedimintSlug(federationId),
    JSON.stringify(fields),
    now,
    now,
  );

  return result.changes > 0 ? url : null;
}

/** Every federation row, for the probe cycle and for review resolution. */
export async function fedimintRows(): Promise<MintRow[]> {
  const db = await getDb();
  return db.all<MintRow>(`SELECT * FROM mints WHERE type = 'fedimint'`);
}

/* ---------- lnurl ---------- */

/**
 * The routing slug an LNURL mint gets, given what the table already holds.
 *
 * `mints.host` carries a UNIQUE index across every ecosystem, so a Cashu mint and an
 * LNURL mint on one hostname would compete for a single slug and — with the existing
 * insert path — the loser would silently not be tracked at all. That is the one outcome
 * worth writing code to avoid: a mint that exists, is reviewable, and has no page.
 *
 * So the clean slug is used whenever it is free, which is very nearly always, and a
 * colliding row takes `lnurl-` in front instead. Decided once at insert and then stored,
 * never recomputed: a mint that took the prefixed slug keeps it even if the row it
 * collided with later disappears, because its URL is already indexed and linked and a
 * silently moving page is worse than a slightly long one.
 */
async function lnurlSlug(preferred: string, url: string): Promise<string | null> {
  const db = await getDb();

  const takenBy = async (slug: string): Promise<string | null> => {
    const row = await db.get<{ url: string }>('SELECT url FROM mints WHERE host = ?', slug);
    return row && row.url !== url ? row.url : null;
  };

  const clash = await takenBy(preferred);
  if (!clash) return preferred;

  const prefixed = LNURL_SLUG_PREFIX + preferred;
  const secondClash = await takenBy(prefixed);
  if (!secondClash) {
    log.info('lnurl slug taken, using prefixed form', { url, slug: prefixed, existing: clash });
    return prefixed;
  }

  log.warn('lnurl slug collision, mint not tracked', { url, slug: preferred, existing: clash });
  return null;
}

/** The `ecosystem_json` an LNURL row starts life with, before anything has probed it. */
function blankLnurlFields(baseUrl: string, identifier: string): LnurlFields {
  return {
    lnurl_id: identifier,
    base_url: baseUrl,
    features: [],
    network: null,
    announced_at: null,
    announcer_pubkey: null,
    mint_pubkey: null,
    funding_available: null,
    probe_endpoint: null,
    invalid_reason: null,
    min_withdrawable_msat: null,
    max_withdrawable_msat: null,
    min_sendable_msat: null,
    max_sendable_msat: null,
    fee_base_msat: null,
    fee_ppm: null,
    lightning_address: null,
    onion_url: null,
    node_alias: null,
    node_uri: null,
    node_capacity_msat: null,
    node_channels: null,
    node_peers: null,
    observed_features: [],
  };
}

/**
 * Insert an LNURL mint by URL alone, with no announcement behind it.
 *
 * For the seed list and for operators added by hand. `status` starts `unknown` and the
 * very next probe cycle decides it, exactly as a seeded Cashu mint works — nothing here
 * claims the mint is up, and `insertMintIfNew`'s rule that an existing row is never
 * touched applies just as strictly.
 *
 * Returns the row key when a row was created, null otherwise.
 */
export async function insertLnurlIfNew(
  rawUrl: string,
  now = Math.floor(Date.now() / 1000),
): Promise<string | null> {
  const normalized = normalizeMintUrl(rawUrl);
  if (!normalized) {
    if (!reportedSkips.has(rawUrl)) {
      reportedSkips.add(rawUrl);
      log.warn('skipped lnurl url', { url: rawUrl.slice(0, 80) });
    }
    return null;
  }

  const db = await getDb();
  const url = lnurlKey(normalized.url);

  const existing = await db.get<{ url: string }>('SELECT url FROM mints WHERE url = ?', url);
  if (existing) return null;

  const host = await lnurlSlug(normalized.host, url);
  if (host === null) return null;

  const result = await db.run(
    `INSERT INTO mints (url, host, type, ecosystem_json, status, first_seen, updated_at)
     VALUES (?, ?, 'lnurl', ?, 'unknown', ?, ?)
     ON CONFLICT DO NOTHING`,
    url,
    host,
    JSON.stringify(blankLnurlFields(normalized.url, lnurlIdentifier(normalized.url, null))),
    now,
    now,
  );

  return result.changes > 0 ? url : null;
}

/**
 * Insert or refresh an LNURL mint from a kind 38174 announcement.
 *
 * **Deduped on the normalized base URL, not on the `d` tag**, and that is the whole
 * reason this function is not a copy of `upsertFedimint`. An LNURL mint's identifier is
 * its funding node's pubkey when it has one and its host otherwise, so the same mint
 * legitimately appears under two different `d` values across its life — announced by
 * host before a funding source was configured, by pubkey afterwards. Keying rows on `d`
 * would split one mint into two pages with half its reviews on each. The `u` tag is the
 * one value present in every form of the event, so it is the key.
 *
 * Unlike `insertMintIfNew` this does update an existing row, because an announcement is
 * the only source of `features`, the network and the operator's own name for the mint.
 * Older announcements are ignored (`announced_at` goes forwards only) so a replayed
 * event from last year cannot overwrite this week's capability list.
 *
 * Two things are deliberately never written here:
 *
 *   - **The status columns.** Whether a mint is up is a probe's answer. An announcement
 *     is not evidence of anything being up.
 *   - **Anything a probe learned.** `mint_pubkey`, the limits, the address, the node
 *     fields and `funding_available` are all carried over from the existing row
 *     untouched. In particular a `mint_pubkey` already observed is *never* cleared by an
 *     announcement that lacks one: identity is sticky, per the kind document.
 *
 * Returns the row's key when a row was created, null when one was merely updated.
 */
export async function upsertLnurl(
  announcement: LnurlAnnouncement,
  now = Math.floor(Date.now() / 1000),
): Promise<string | null> {
  const db = await getDb();
  const url = lnurlKey(announcement.baseUrl);

  const existing = await db.get<MintRow>('SELECT * FROM mints WHERE url = ?', url);
  const previous = existing ? parseEcosystem<LnurlFields>(existing) : null;

  if (previous && (previous.announced_at ?? 0) > announcement.announcedAt) return null;

  /*
   * The stored pubkey wins over the announcement's.
   *
   * A probe reads `mintPubkey` off the mint itself; an announcement is a stranger's
   * claim about it. Where both exist the observed one is the better evidence, and where
   * only the announcement has one it is still worth keeping, so this prefers the probe
   * and falls back rather than overwriting in either direction.
   */
  const mintPubkey = previous?.mint_pubkey ?? announcement.mintPubkey;

  const fields: LnurlFields = {
    ...(previous ?? blankLnurlFields(announcement.baseUrl, announcement.identifier)),
    lnurl_id: lnurlIdentifier(announcement.baseUrl, mintPubkey),
    base_url: announcement.baseUrl,
    features: announcement.features,
    network: announcement.network,
    announced_at: announcement.announcedAt,
    announcer_pubkey: announcement.announcerPubkey,
    mint_pubkey: mintPubkey,
  };

  if (!existing) {
    const host = await lnurlSlug(announcement.slug, url);
    if (host === null) return null;

    await db.run(
      `INSERT INTO mints (url, host, type, name, description, icon_url, ecosystem_json,
                          status, first_seen, updated_at)
       VALUES (?, ?, 'lnurl', ?, ?, ?, ?, 'unknown', ?, ?)
       ON CONFLICT DO NOTHING`,
      url,
      host,
      announcement.name,
      announcement.about,
      announcement.picture,
      JSON.stringify(fields),
      now,
      now,
    );
    return url;
  }

  await db.run(
    `UPDATE mints SET
       name = COALESCE(?, name),
       description = COALESCE(?, description),
       icon_url = COALESCE(?, icon_url),
       ecosystem_json = ?,
       updated_at = ?
     WHERE url = ?`,
    announcement.name,
    announcement.about,
    announcement.picture,
    JSON.stringify(fields),
    now,
    url,
  );

  return null;
}

/** Every LNURL row, for the probe cycle and for review resolution. */
export async function lnurlRows(): Promise<MintRow[]> {
  const db = await getDb();
  return db.all<MintRow>(`SELECT * FROM mints WHERE type = 'lnurl'`);
}

/** Canonical mint URL for a normalized slug, or null if no such mint is tracked. */
export async function mintUrlByHost(host: string): Promise<string | null> {
  const db = await getDb();
  const row = await db.get<{ url: string }>('SELECT url FROM mints WHERE host = ?', host);
  return row?.url ?? null;
}

export async function allMintRows(): Promise<MintRow[]> {
  const db = await getDb();
  return db.all<MintRow>('SELECT * FROM mints');
}

export async function mintByHost(host: string): Promise<MintRow | undefined> {
  const db = await getDb();
  return db.get<MintRow>('SELECT * FROM mints WHERE host = ?', host);
}

export async function mintByUrl(url: string): Promise<MintRow | undefined> {
  const db = await getDb();
  return db.get<MintRow>('SELECT * FROM mints WHERE url = ?', url);
}

/** Resolve a mint by the pubkey it publishes in /v1/info, for reviews with only a `d` tag. */
export async function mintUrlByPubkey(pubkey: string): Promise<string | null> {
  const db = await getDb();
  const row = await db.get<{ url: string }>('SELECT url FROM mints WHERE pubkey = ? LIMIT 1', pubkey);
  return row?.url ?? null;
}