const { query } = require('../../utils/db')

// Find the identity row for an external (provider, subject) pair. This is the
// link-only login lookup: no row → no account → login refused.
async function findByProviderSubject(provider, subject) {
  const rows = await query(
    'SELECT * FROM user_identities WHERE provider = ? AND subject = ? LIMIT 1',
    [provider, subject],
  )
  return rows[0] || null
}

// All identities linked to a given internal user (for the Account page).
async function listForUser(userId) {
  return query(
    `SELECT id, provider, subject, email, display_name, avatar_url, created_at
       FROM user_identities WHERE user_id = ? ORDER BY provider, created_at`,
    [userId],
  )
}

async function insert({ userId, provider, subject, email = null, displayName = null, avatarUrl = null }) {
  const res = await query(
    `INSERT INTO user_identities (user_id, provider, subject, email, display_name, avatar_url)
     VALUES (?, ?, ?, ?, ?, ?)`,
    [userId, provider, subject, email, displayName, avatarUrl],
  )
  return res.insertId
}

// Refresh the name and avatar a provider reported at sign-in (Steam, D394). Only
// what the provider sent is written: a lookup that failed leaves the last good
// values in place rather than blanking them.
async function updateProfile(id, { displayName, avatarUrl }) {
  const sets = []
  const vals = []
  if (displayName) { sets.push('display_name = ?'); vals.push(displayName) }
  if (avatarUrl) { sets.push('avatar_url = ?'); vals.push(avatarUrl) }
  if (!sets.length) return 0
  const res = await query(`UPDATE user_identities SET ${sets.join(', ')} WHERE id = ?`, [...vals, id])
  return Number(res.affectedRows || 0)
}

// Remove a user's link to a provider — every identity of it, or, given an
// identity id, that one only (a user may hold several Steam accounts). Returns
// rows deleted.
async function deleteForUserProvider(userId, provider, identityId = null) {
  if (identityId != null) {
    const res = await query(
      'DELETE FROM user_identities WHERE user_id = ? AND provider = ? AND id = ?',
      [userId, provider, identityId],
    )
    return Number(res.affectedRows || 0)
  }
  const res = await query(
    'DELETE FROM user_identities WHERE user_id = ? AND provider = ?',
    [userId, provider],
  )
  return Number(res.affectedRows || 0)
}

module.exports = { findByProviderSubject, listForUser, insert, updateProfile, deleteForUserProvider }