/**
 * Optional Discord bot initd unit (`bare-os-discord`).
 * Registered only when the guest VFS has ~/.discord/.env with DISCORD_TOKEN=.
 * Hidden from systemctl when that file is missing.
 */
import {
  findBareServiceDefinition,
  registerBareService,
  startBareService,
  stopBareService,
  unregisterBareService
} from '../initd/bare-initd.js'
import { appendVarLog, BARE_OS_VAR_LOG_DIR } from '../vfs/bare-os-var-log.js'
import {
  normalizeDiscordToken,
  parseDotEnvText
} from './bare-discord-js-loader.js'
// Static CJS import so bare-pack rewrites the binding into app.bundle.
// Runtime require of a sibling path is MODULE_NOT_FOUND under bare:/app.bundle/.
import discordCommandsNs from './bare-os-discord-commands-guest.cjs'

const discordCommands =
  discordCommandsNs &&
  (discordCommandsNs.dispatchInteraction || discordCommandsNs.buildSlashCommands)
    ? discordCommandsNs
    : discordCommandsNs && discordCommandsNs.default
      ? discordCommandsNs.default
      : discordCommandsNs

export const BARE_OS_DISCORD_SERVICE_ENV = '~/.discord/.env'
export const BARE_OS_DISCORD_LOG = `${BARE_OS_VAR_LOG_DIR}/discord.log`
export const BARE_OS_DISCORD_UNIT = 'bare-os-discord'
/** Extra guest files scanned for DISCORD_ID_WHITELIST / guild / user-install. */
export const BARE_OS_DISCORD_EXTRA_ENV_FILES = [
  '~/.discord/.env',
  '~/.discord.env',
  '~/discord.env',
  '~/.env',
  './.env'
]

/** @type {import('discord.js').Client | null} */
let discordServiceClient = null
/** Live session ctx (updated after login so commands are not stuck on guest). */
let discordServiceCtx = null

export function bindBareOsDiscordSessionCtx(ctx) {
  if (ctx) discordServiceCtx = ctx
  return discordServiceCtx
}

/** @param {Record<string, string | undefined>} env */
export function bareOsDiscordInitdEnabled(env) {
  const v = env && (env.BARE_OS_DISCORD_INITD || env.BARE_OS_DISCORD)
  if (v === '0' || v === 'false') return false
  return true
}

function discordVfsText(ctx, buf) {
  if (!buf) return ''
  if (typeof ctx.b4a?.toString === 'function') return ctx.b4a.toString(buf)
  return Buffer.from(buf).toString('utf8')
}

async function readBareOsDiscordDotEnvFile(ctx, path) {
  const vfs = ctx && ctx.vfs
  if (!vfs || typeof vfs.readFile !== 'function') return null
  let buf
  try {
    buf = await vfs.readFile(path)
  } catch {
    return null
  }
  if (!buf) return null
  return parseDotEnvText(discordVfsText(ctx, buf))
}

function discordSessionEnvMaps(ctx) {
  if (!ctx.env || typeof ctx.env !== 'object') ctx.env = {}
  const maps = [ctx.env]
  if (ctx.vfs && ctx.vfs.env && typeof ctx.vfs.env === 'object' && ctx.vfs.env !== ctx.env) {
    maps.push(ctx.vfs.env)
  }
  return maps
}

/**
 * Copy non-empty Discord extras onto both `ctx.env` and `ctx.vfs.env`.
 * Session values win; empty strings do not block a file value.
 */
export function applyDiscordExtrasToSession(ctx, parsed) {
  if (!parsed || !ctx) return
  const maps = discordSessionEnvMaps(ctx)
  const pairs = [
    ['DISCORD_GUILD_ID', parsed.DISCORD_GUILD_ID],
    [
      'DISCORD_ID_WHITELIST',
      parsed.DISCORD_ID_WHITELIST || parsed.BARE_OS_DISCORD_ID_WHITELIST
    ],
    [
      'DISCORD_USER_INSTALL',
      parsed.DISCORD_USER_INSTALL || parsed.BARE_OS_DISCORD_USER_INSTALL
    ]
  ]
  for (const [key, raw] of pairs) {
    const v = raw == null ? '' : String(raw).trim()
    if (!v) continue
    for (const env of maps) {
      if (!String(env[key] || '').trim()) env[key] = v
    }
  }
}

function discordSessionWhitelist(ctx) {
  const maps = []
  if (ctx && ctx.env && typeof ctx.env === 'object') maps.push(ctx.env)
  if (ctx && ctx.vfs && ctx.vfs.env && typeof ctx.vfs.env === 'object') {
    maps.push(ctx.vfs.env)
  }
  for (const env of maps) {
    const v = String(
      env.DISCORD_ID_WHITELIST || env.BARE_OS_DISCORD_ID_WHITELIST || ''
    ).trim()
    if (v) return v
  }
  return ''
}

export async function readBareOsDiscordServiceEnv(ctx) {
  const parsed = await readBareOsDiscordDotEnvFile(ctx, BARE_OS_DISCORD_SERVICE_ENV)
  if (!parsed) return null
  const token = normalizeDiscordToken(
    parsed.DISCORD_TOKEN || parsed.BOT_TOKEN || ''
  )
  if (!token) return null
  return {
    token,
    guildId: String(parsed.DISCORD_GUILD_ID || '').trim(),
    whitelist: String(
      parsed.DISCORD_ID_WHITELIST || parsed.BARE_OS_DISCORD_ID_WHITELIST || ''
    ).trim(),
    userInstall: String(
      parsed.DISCORD_USER_INSTALL || parsed.BARE_OS_DISCORD_USER_INSTALL || ''
    ).trim()
  }
}

/**
 * Load token from ~/.discord/.env, then fill whitelist / guild / user-install
 * from that file, sibling env files (~/.env, …), and both session env maps.
 */
export async function hydrateBareOsDiscordSessionEnv(ctx) {
  const creds = await readBareOsDiscordServiceEnv(ctx)
  if (creds) applyDiscordExtrasToSession(ctx, creds)
  const seen = Object.create(null)
  for (const path of BARE_OS_DISCORD_EXTRA_ENV_FILES) {
    if (!path || seen[path]) continue
    seen[path] = true
    const parsed = await readBareOsDiscordDotEnvFile(ctx, path)
    if (parsed) applyDiscordExtrasToSession(ctx, parsed)
  }
  if (creds) {
    const wl = discordSessionWhitelist(ctx)
    if (wl) creds.whitelist = wl
    const guild = String(
      (ctx.env && ctx.env.DISCORD_GUILD_ID) || creds.guildId || ''
    ).trim()
    if (guild) creds.guildId = guild
    const ui = String(
      (ctx.env && ctx.env.DISCORD_USER_INSTALL) || creds.userInstall || ''
    ).trim()
    if (ui) creds.userInstall = ui
  }
  return creds
}

function discordServiceLog(ctx, line) {
  try {
    ctx.console?.log?.('[bare-os-discord] ' + line)
  } catch {
    /* ignore */
  }
  void appendVarLog(ctx, BARE_OS_DISCORD_LOG, 'discord', line)
}

async function startBareOsDiscord(ctx) {
  const creds = await hydrateBareOsDiscordSessionEnv(ctx)
  if (!creds) {
    throw new Error('missing ' + BARE_OS_DISCORD_SERVICE_ENV + ' (DISCORD_TOKEN=)')
  }
  const dj = ctx.bare && ctx.bare.discordJS
  if (!dj || typeof dj.Client !== 'function') {
    throw new Error('ctx.bare.discordJS is unavailable')
  }
  discordServiceCtx = ctx
  if (discordServiceClient) return
  applyDiscordExtrasToSession(ctx, creds)

  const osName =
    (typeof process !== 'undefined' && process.platform) || 'darwin'
  const client = new dj.Client({
    intents: [dj.GatewayIntentBits.Guilds],
    ws: {
      identifyProperties: {
        os: osName,
        browser: 'bare-os',
        device: 'bare-os'
      }
    }
  })
  if (dj.Events && dj.Events.Error) {
    client.on(dj.Events.Error, function (err) {
      discordServiceLog(ctx, 'client error: ' + ((err && err.message) || err))
    })
  }
  if (dj.Events && dj.Events.InteractionCreate) {
    client.on(dj.Events.InteractionCreate, async function (interaction) {
      const live = discordServiceCtx || ctx
      if (
        discordCommands &&
        typeof discordCommands.syncSessionIdentity === 'function'
      ) {
        discordCommands.syncSessionIdentity(live)
      }
      const dispatch =
        discordCommands &&
        (discordCommands.dispatchInteraction ||
          (discordCommands.default &&
            discordCommands.default.dispatchInteraction))
      if (typeof dispatch === 'function') {
        await dispatch(live, interaction)
        return
      }
      if (
        !interaction.isChatInputCommand ||
        !interaction.isChatInputCommand()
      ) {
        return
      }
      if (interaction.commandName !== 'ping') return
      const uid =
        interaction.user && interaction.user.id ? String(interaction.user.id) : ''
      const allowed =
        discordCommands && typeof discordCommands.userAllowed === 'function'
          ? discordCommands.userAllowed(live, uid, interaction)
          : true
      if (!allowed) {
        try {
          await interaction.reply({
            content:
              'Access denied. Your Discord user id is not on DISCORD_ID_WHITELIST.',
            flags: 64
          })
        } catch (err) {
          discordServiceLog(
            ctx,
            'deny failed: ' + ((err && err.message) || err)
          )
        }
        return
      }
      try {
        await interaction.reply({ content: 'pong' })
      } catch (err) {
        discordServiceLog(
          ctx,
          '/ping failed: ' + ((err && err.message) || err)
        )
      }
    })
  }
  await client.login(creds.token)
  discordServiceClient = client
  const tag =
    client.user && client.user.tag ? client.user.tag : String(client.user)
  discordServiceLog(ctx, 'logged in as ' + tag)
  if (typeof dj.REST === 'function' && dj.Routes) {
    try {
      const rest = new dj.REST().setToken(creds.token)
      const build =
        discordCommands &&
        (discordCommands.buildSlashCommands ||
          (discordCommands.default &&
            discordCommands.default.buildSlashCommands))
      const body =
        typeof build === 'function'
          ? await Promise.resolve(build(dj, ctx))
          : [
              new dj.SlashCommandBuilder()
                .setName('ping')
                .setDescription('Replies with pong.')
                .toJSON()
            ]
      const setReg =
        discordCommands &&
        (discordCommands.setPluginRegistrar ||
          (discordCommands.default && discordCommands.default.setPluginRegistrar))
      const userInstallOn =
        discordCommands &&
        typeof discordCommands.userInstallEnabled === 'function'
          ? discordCommands.userInstallEnabled(ctx)
          : true
      async function registerBody(next) {
        if (
          userInstallOn &&
          discordCommands &&
          typeof discordCommands.enableUserInstallApp === 'function'
        ) {
          try {
            await discordCommands.enableUserInstallApp(rest, dj.Routes)
          } catch (err) {
            discordServiceLog(
              ctx,
              'user-install app config failed: ' +
                ((err && err.message) || err) +
                ' (enable User Install under Developer Portal → Installation)'
            )
          }
        }
        if (
          discordCommands &&
          typeof discordCommands.putSlashCommands === 'function'
        ) {
          const put = await discordCommands.putSlashCommands(
            rest,
            dj.Routes,
            client.user.id,
            next,
            { guildId: creds.guildId, userInstall: userInstallOn }
          )
          if (put.global) {
            discordServiceLog(
              ctx,
              'registered ' +
                next.length +
                ' global commands' +
                (userInstallOn ? ' (user-install + guild)' : '')
            )
          }
          if (put.guild) {
            discordServiceLog(
              ctx,
              'registered ' +
                next.length +
                ' commands for guild ' +
                creds.guildId
            )
          }
          return
        }
        if (creds.guildId) {
          await rest.put(
            dj.Routes.applicationGuildCommands(client.user.id, creds.guildId),
            { body: next }
          )
        } else {
          await rest.put(dj.Routes.applicationCommands(client.user.id), {
            body: next
          })
        }
      }
      if (typeof setReg === 'function') {
        setReg(async function () {
          const next = await Promise.resolve(build(dj, ctx))
          await registerBody(next)
        })
      }
      await registerBody(body)
      if (userInstallOn) {
        const url =
          discordCommands &&
          typeof discordCommands.userInstallAuthorizeUrl === 'function'
            ? discordCommands.userInstallAuthorizeUrl(client.user.id)
            : ''
        if (url) {
          discordServiceLog(ctx, 'add to your Discord profile: ' + url)
        }
        const wlN =
          discordCommands &&
          typeof discordCommands.whitelistCount === 'function'
            ? discordCommands.whitelistCount(ctx)
            : 0
        if (wlN) {
          discordServiceLog(
            ctx,
            'DISCORD_ID_WHITELIST active (' + wlN + ' user id(s))'
          )
        } else {
          discordServiceLog(
            ctx,
            'user-install is on and DISCORD_ID_WHITELIST is empty — user-install / DM commands are denied'
          )
        }
      }
    } catch (err) {
      discordServiceLog(
        ctx,
        'slash register failed: ' + ((err && err.message) || err)
      )
    }
  }
}

async function stopBareOsDiscord(_ctx) {
  const c = discordServiceClient
  discordServiceClient = null
  discordServiceCtx = null
  if (!c) return
  await Promise.resolve(c.destroy()).catch(function () {})
}

/**
 * Register or drop the unit from systemctl based on ~/.discord/.env.
 * @param {Record<string, unknown>} ctx
 */
export async function syncBareOsDiscordInitd(ctx) {
  const env =
    ctx && ctx.env && typeof ctx.env === 'object'
      ? /** @type {Record<string, string | undefined>} */ (ctx.env)
      : {}
  const want =
    bareOsDiscordInitdEnabled(env) && (await readBareOsDiscordServiceEnv(ctx))
  const have = Boolean(findBareServiceDefinition(BARE_OS_DISCORD_UNIT))
  if (!want) {
    if (have) {
      try {
        await stopBareService(ctx, BARE_OS_DISCORD_UNIT)
      } catch {
        /* may already be inactive */
      }
      unregisterBareService(BARE_OS_DISCORD_UNIT)
    }
    return false
  }
  registerBareService({
    name: BARE_OS_DISCORD_UNIT,
    description:
      'Bare OS Discord bot (/bare /sys /svc /fs /net …); requires ~/.discord/.env',
    logPath: BARE_OS_DISCORD_LOG,
    start: startBareOsDiscord,
    stop: stopBareOsDiscord
  })
  return true
}

/**
 * After identity unlock: show+start the unit only when ~/.discord/.env exists.
 * @param {Record<string, unknown>} ctx
 */
export async function maybeStartBareOsDiscordAfterIdentity(ctx) {
  bindBareOsDiscordSessionCtx(ctx)
  const shown = await syncBareOsDiscordInitd(ctx)
  if (!shown) return
  try {
    await startBareService(ctx, BARE_OS_DISCORD_UNIT)
  } catch (e) {
    const msg = (e && /** @type {{ message?: string }} */ (e).message) || String(e)
    discordServiceLog(ctx, 'start failed: ' + msg)
  }
}

/** Drop the unit on logout so it does not appear for the next session. */
export async function stopBareOsDiscordInitd(ctx) {
  if (!findBareServiceDefinition(BARE_OS_DISCORD_UNIT)) return
  try {
    await stopBareService(ctx, BARE_OS_DISCORD_UNIT)
  } catch {
    /* ignore */
  }
  unregisterBareService(BARE_OS_DISCORD_UNIT)
}