// SQL for the two tables the access resolver reads: forum grants (path 3) and
// staff leadership overrides (§2.5.1).
//
// Kept separate from teams.db.js on purpose. The four authority paths are four
// tables answering four questions, and the single most important structural rule
// in TEAMS.md is that no resolver reads another path's table — a file boundary is
// a cheap way to make crossing one visible in a diff.

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

// ── team_forum_grants (path 3) ─────────────────────────────────────────────

const GRANT_COLUMNS = `
  id, team_id, user_id, username, granted_by, granted_username, granted_at, reason,
  revoked_by, revoked_username, revoked_at, revoke_reason`

/** The caller's ACTIVE grant on a team, or undefined. At most one, by the unique key. */
async function activeGrant(teamId, userId) {
  const rows = await query(
    `SELECT ${GRANT_COLUMNS} FROM team_forum_grants
     WHERE team_id = ? AND user_id = ? AND revoked_at IS NULL`,
    [teamId, userId],
  )
  return rows[0]
}

/** The whole ledger for a team, revoked rows included — the admin grant view. */
async function grantLedger(teamId) {
  return query(
    `SELECT ${GRANT_COLUMNS} FROM team_forum_grants WHERE team_id = ? ORDER BY granted_at DESC, id DESC`,
    [teamId],
  )
}

/** Active grants only, for the "Forum guests" list and the per-team cap. */
async function activeGrants(teamId) {
  return query(
    `SELECT ${GRANT_COLUMNS} FROM team_forum_grants WHERE team_id = ? AND revoked_at IS NULL
     ORDER BY granted_at`,
    [teamId],
  )
}

/** How many active grants a team currently holds — the §2.5 per-Team cap reads this. */
async function activeGrantCount(teamId) {
  const rows = await query(
    'SELECT COUNT(*) AS n FROM team_forum_grants WHERE team_id = ? AND revoked_at IS NULL',
    [teamId],
  )
  return Number(rows[0]?.n || 0)
}

/**
 * Issue a grant.
 *
 * Writes nothing but this table — that is the non-contamination invariant, and it
 * is a property of this function being the ONLY writer on the grant path rather
 * than of anyone remembering it at the call site. The username snapshots are
 * taken here so the ledger still reads after either account is deleted (§2.10).
 */
async function insertGrant({ teamId, userId, username, grantedBy, grantedUsername, reason }) {
  const res = await query(
    `INSERT INTO team_forum_grants (team_id, user_id, username, granted_by, granted_username, reason)
     VALUES (?, ?, ?, ?, ?, ?)`,
    [teamId, userId, username, grantedBy, grantedUsername, reason ?? null],
  )
  return res.insertId
}

/**
 * Revoke the active grant, if there is one.
 *
 * An UPDATE of the existing row rather than a delete: the table is a ledger as
 * well as the current state, and `revoked_at` is what moves a row out of the
 * unique key (the generated `active_marker` goes NULL) while keeping the history.
 */
async function revokeGrant({ teamId, userId, revokedBy, revokedUsername, reason }) {
  const res = await query(
    `UPDATE team_forum_grants
        SET revoked_at = NOW(), revoked_by = ?, revoked_username = ?, revoke_reason = ?
      WHERE team_id = ? AND user_id = ? AND revoked_at IS NULL`,
    [revokedBy, revokedUsername, reason ?? null, teamId, userId],
  )
  return res.affectedRows > 0
}

// ── team_leader_overrides (§2.5.1) ─────────────────────────────────────────

const OVERRIDE_COLUMNS = 'team_id, member_key, effect, actor_user_id, actor_username, reason, created_at'

async function overridesForTeam(teamId) {
  return query(`SELECT ${OVERRIDE_COLUMNS} FROM team_leader_overrides WHERE team_id = ? ORDER BY member_key`,
    [teamId])
}

async function overrideFor(teamId, memberKey) {
  const rows = await query(
    `SELECT ${OVERRIDE_COLUMNS} FROM team_leader_overrides WHERE team_id = ? AND member_key = ?`,
    [teamId, memberKey],
  )
  return rows[0]
}

/**
 * Set or replace one override.
 *
 * The projection is never touched by this — `team_members.is_leader` keeps saying
 * what the game says and this keeps saying what staff decided, which is the entire
 * point (§2.5.1). An override applied INTO the projection would be clobbered by
 * the next sync, fifteen minutes later.
 */
async function setOverride({ teamId, memberKey, effect, actorUserId, actorUsername, reason }) {
  await query(
    `INSERT INTO team_leader_overrides (team_id, member_key, effect, actor_user_id, actor_username, reason)
     VALUES (?, ?, ?, ?, ?, ?)
     ON DUPLICATE KEY UPDATE
       effect = VALUES(effect), actor_user_id = VALUES(actor_user_id),
       actor_username = VALUES(actor_username), reason = VALUES(reason), created_at = NOW()`,
    [teamId, memberKey, effect, actorUserId, actorUsername, reason],
  )
}

async function clearOverride(teamId, memberKey) {
  const res = await query('DELETE FROM team_leader_overrides WHERE team_id = ? AND member_key = ?',
    [teamId, memberKey])
  return res.affectedRows > 0
}

module.exports = {
  activeGrant,
  grantLedger,
  activeGrants,
  activeGrantCount,
  insertGrant,
  revokeGrant,
  overridesForTeam,
  overrideFor,
  setOverride,
  clearOverride,
}