// ── The `admin.users.detail` slot's handlers ──────────────────────────────
//
// What an operator can see and do about one website user's Rust identity. The
// user id is the PARENT's — `req.params.id` off core's `/admin/users/:id` — and
// every statement here is scoped by it, so a panel opened on one user cannot
// read or write another's rows by editing a path segment.

const core = require('../../core')

const links = require('../../model/links/links.model')
const permissionsDb = require('../../model/permissions/permissions.db')
const permissions = require('../../model/permissions/permissions.model')
const servers = require('../../model/servers/servers.model')

const log = core.logger('admin')

/**
 * GET /admin/users/:id/rust/links
 *
 * The linked Steam accounts and, per server, what this module knows about the
 * player behind them — all-time rather than this wipe's, because an operator
 * looking at a user wants their history and the public leaderboard already
 * answers the other question.
 *
 * **An empty array is an answer.** Most users have no Rust link at all, and the
 * panel renders nothing rather than an error for them.
 */
async function listLinks(req, res) {
  try {
    res.json({ links: await links.forAdmin(req.params.id) })
  } catch (err) {
    log.error('failed to read a user’s Rust links', { error: err.message })
    res.status(500).json({ message: 'Failed to read this user’s Rust accounts' })
  }
}

/**
 * DELETE /admin/users/:id/rust/links/:steamId — staff sever a link (D25).
 *
 * **This is the counterweight to D23.** The site refuses to move a Steam id that
 * another website account already holds, and the player's own way out is
 * `/unlink` in game — which is no way out at all for somebody who has lost access
 * to that Steam account, or to the site account holding it. Staff are that route.
 *
 * Scoped by the parent user id in the statement rather than checked first: the
 * ownership test and the deletion are one operation, and a link that belongs to a
 * different user answers 404 from the page it was not on.
 */
async function removeLink(req, res) {
  const { steamId } = req.params
  const userId = req.params.id

  try {
    const removed = await links.unlinkOwned(steamId, userId)

    if (!removed) return res.status(404).json({ message: 'That account is not linked to this user' })

    // The one write this panel has, so it is the one thing here worth an audit
    // row: after phase 7 a link is what permissions are granted against, and
    // "who severed it" stops being a curiosity.
    await core.activity.log({
      req,
      action: 'rust.account.unlink.staff',
      detail: { steamId, userId: Number(userId) },
    })

    return res.json({ unlinked: true })
  } catch (err) {
    log.error('failed to unlink a Steam account', { error: err.message })
    return res.status(500).json({ message: 'Failed to unlink that account' })
  }
}

/**
 * GET /admin/users/:id/rust/permissions
 *
 * What this person may do in game, and — the part that is easy to leave out —
 * whether any of it reaches anybody. A grant against an account with no linked
 * Steam id is authored, stored, pushed nowhere and looks identical to a working
 * one on every screen that does not say so.
 */
async function listPermissions(req, res) {
  const userId = Number(req.params.id)

  try {
    const [groups, groupPermissions, members, grants, allLinks] = await Promise.all([
      permissionsDb.listGroups(),
      permissionsDb.listGroupPermissions(),
      permissionsDb.listGroupMembers(),
      permissionsDb.listGrants({ userId }),
      permissionsDb.listLinks(),
    ])

    const theirs = new Set(
      members.filter((row) => row.userId === userId).map((row) => row.groupName),
    )

    const carried = new Map()
    for (const row of groupPermissions) {
      if (!carried.has(row.groupName)) carried.set(row.groupName, [])
      carried.get(row.groupName).push(row.permission)
    }

    res.json({
      groups: groups
        .filter((group) => theirs.has(group.name))
        .map((group) => ({
          name: group.name,
          title: group.title,
          scope: group.scope,
          permissions: carried.get(group.name) || [],
        })),
      grants: permissions.collapseGrants(grants).map((grant) => ({
        id: grant.id,
        permission: grant.permission,
        scope: grant.scope,
        source: grant.source,
        note: grant.note,
        grantedAt: grant.grantedAt,
      })),
      reaches: allLinks.filter((link) => link.userId === userId).map((link) => link.steamId),
    })
  } catch (err) {
    log.error('failed to read a user’s Rust permissions', { error: err.message })
    res.status(500).json({ message: 'Failed to read this user’s Rust permissions' })
  }
}

/** POST /admin/users/:id/rust/permissions/grants */
async function addGrant(req, res) {
  const userId = Number(req.params.id)
  const permission = permissions.normaliseName(req.body.permission)
  const scope = String(req.body.scope || permissions.FLEET)

  try {
    if (scope !== permissions.FLEET) {
      const known = await servers.listForAdmin()
      if (!known.some((row) => row.id === scope)) {
        return res.status(400).json({ message: 'That scope names no configured server' })
      }
    }

    const { inserted } = await permissionsDb.insertGrant({
      userId,
      permission,
      scope,
      source: 'admin',
      note: null,
      grantedBy: req.user ? req.user.id : null,
    })

    if (inserted) {
      await permissionsDb.markDirty(scope)
      await core.activity.log({
        req,
        action: 'rust.perm.grant',
        detail: { userId, permission, scope },
      })
    }

    return res.status(inserted ? 201 : 200).json({ granted: inserted })
  } catch (err) {
    log.error('failed to grant a permission', { userId, permission, error: err.message })
    return res.status(400).json({ message: 'That permission could not be granted' })
  }
}

/**
 * DELETE /admin/users/:id/rust/permissions/grants/:grantId
 *
 * **Scoped by the user as well as by the grant**, like every other write in this
 * panel: a grant id belonging to somebody else answers `404` rather than
 * removing a privilege from a person whose page nobody was looking at.
 */
async function removeGrant(req, res) {
  const userId = Number(req.params.id)
  const grantId = Number(req.params.grantId)

  try {
    const grant = await permissionsDb.getGrant(grantId)

    if (!grant || grant.userId !== userId) {
      return res.status(404).json({ message: 'That grant does not belong to this user' })
    }

    await permissionsDb.deleteGrant(grantId)
    await permissionsDb.markDirty(grant.scope)

    await core.activity.log({
      req,
      action: 'rust.perm.revoke',
      detail: { userId, permission: grant.permission, scope: grant.scope },
    })

    return res.status(204).end()
  } catch (err) {
    log.error('failed to remove a grant', { userId, grant: grantId, error: err.message })
    return res.status(500).json({ message: 'Failed to remove that permission' })
  }
}

module.exports = { listLinks, removeLink, listPermissions, addGrant, removeGrant }