#!/usr/bin/env bash

shopt -s nullglob dotglob extglob

###
# logger
###

declare -A levels=(
  [debug]=1 [info]=2
  [warn]=3 [error]=4
)

log() {
  if [[ -v LEVEL ]] && (( levels[$level] <= levels[$LEVEL] )); then
    printf "%s: $1\n" "${LEVEL^^}" "${@:2}" >&"$log"
  fi
}

debug() {
  LEVEL=debug log "$@"
}

info() {
  LEVEL=info log "$@"
}

warn() {
  LEVEL=warn log "$@"
}

error() {
  LEVEL=error log "$@"
}

###
# argument parser for parsing arguments
##

original_args=("$0" "$@")
declare -A opts

while (( $# )); do
  case $1 in
  --*=*)
    key=${1#--} key=${key%%=*}
    opts[$key]=${1#--*=}
    ;;
  --no-*)
    key=${1#--no-}
    opts[$key]=no
    ;;
  --)
    shift
    break
    ;;
  --*)
    key=${1#--}
    opts[$key]=yes
    ;;
  *)
    break
  esac

  shift
done

###
# default config
##

server=${opts[server]:-irc.libera.chat}
tls=${opts[tls]:-no}

if [[ $tls = yes ]]; then
  if ! hash socat 2>/dev/null; then
    printf 'please install socat to use tls with rowbot.\n' >&2
    exit 1
  fi

  if [[ -v opts[client-cert] ]]; then
    client_cert=${opts[client-cert]}
  fi

  port=${opts[port]:-6697}
else
  port=${opts[port]:-6667}
fi

nick=${opts[nick]:-rowbot-dev}
ident=${opts[ident]:-rowbot}
realname=${opts[realname]:-rowbot}
chan=${opts[chan]:-}
trigger=${opts[trigger]:-\`}
fact_root=${opts[fact-root]:-.}
reload=${opts[reload]:-no}
dev=${opts[dev]:-no}

if [[ -v USER ]]; then
  owner=${opts[owner]:-"$USER"}
else
  owner=${opts[owner]:-uplime}
fi

level=${opts[log-level]:-info}

if [[ $reload = yes ]]; then
  log=$LOG_FD
elif [[ ${opts[log]} ]]; then
  exec {log}>"${opts[log]}"
else
  log=1
fi

###
# utilities
###

cleanup() {
  if [[ -v tls_pid || $tls = no ]]; then
    exec {in_sock}>&- {out_sock}>&- {log}>&-
  fi

  if [[ -v tls_pid ]]; then
    kill "$tls_pid"
    rm -rf "$sock_dir"
  fi

  if [[ -v ping_pid ]]; then
    kill "$ping_pid"
  fi
}

trap cleanup EXIT

alarm-handler() {
  ping "row your bot gently down the stream"

  if [[ $keep_trying = yes ]]; then
    info "trying for %s again" "$desired_nick"
    nick "$desired_nick"
  fi
}

trap alarm-handler ALRM

###
# reload code
###

if [[ $reload = yes ]]; then
  in_sock=$IN_SOCK out_sock=$OUT_SOCK
  trigger=$TRIGGER dev=$DEV level=$LOG_LEVEL
  registered=$REGISTERED

  debug "doing a reload. pid is %d" "$$"

  if [[ -v KEEP_TRYING ]]; then
    keep_trying=$KEEP_TRYING desired_nick=$DESIRED
  fi

  if [[ $tls = yes ]]; then
    sock_dir=$SOCK_DIR
    tls_pid=$tls_pid
  fi

  if [[ -v PING_PID ]]; then
    ping_pid=$PING_PID
  fi

  nick=$NICK ident=$IDENT

  if [[ -v HOST ]]; then
    host=$HOST
  fi
fi

###
# net code
###

if [[ $reload = no && $tls = yes ]]; then
  sock_dir=$(mktemp -d)
  mkfifo "$sock_dir"/rb{in,out}

  if [[ -v client_cert ]]; then
    if [[ ! -f $client_cert ]]; then
      error "client certificate not found: %s" "$client_cert"
      exit 1
    fi

    conn_args=OPENSSL:$server:$port,cert=$client_cert
  else
    conn_args=OPENSSL:$server:$port
  fi

  socat "$conn_args" - <"$sock_dir"/rbin >"$sock_dir"/rbout &
  tls_pid=$!
  debug "created tls connection (pid %d)" "$tls_pid"
  exec {out_sock}>"$sock_dir"/rbin {in_sock}<"$sock_dir"/rbout
elif [[ $reload = no ]]; then
  exec {sock}<>/dev/tcp/"$server"/"$port"
  in_sock=$sock out_sock=$sock
  debug "created plaintext connection"
fi

send() {
  local fmt
  printf -v fmt "$1" "${@:2}"
  printf '%s\r\n' "$fmt" >&"$out_sock"
  debug "sending line: %s" "$fmt"
}

recv() {
  declare -n sock_line=$1
  IFS= read -r "$1" <&"$in_sock"
  sock_line=${sock_line%$'\r'}
  debug "received line: %s" "$sock_line"
}

###
# irc recv code
###

on_ERROR() {
  error "${params[0]}"
  exit
}

on_JOIN() {
  info "%s has joined %s" "$from" "${params[0]}"
}

on_MODE() {
  if (( ${#params[@]} == 2 )); then
    info "%s sets mode(s) %s on %s" "$from" "${params[1]}" "${params[0]}"
  elif (( ${#params[@]} > 2 )); then
    info "%s: %s sets mode(s) %s" "${params[0]}" "$from" "${params[*]:1}"
  fi
}

on_NICK() {
  if [[ $from = $nick ]]; then
    nick=${params[0]}
  fi

  info "%s has changed their name to %s" "$from" "${params[0]}"
}

on_NOTICE() {
  info "[%s/%s] %s" "$from" "${params[0]}" "${params[1]}"
}

on_PART() {
  if (( ${#params[@]} > 1 )); then
    info "%s has left %s: %s" "$from" "${params[0]}" "${params[1]}"
  else
    info "%s has left %s" "$from" "${params[0]}"
  fi
}

on_PING() {
  pong "${params[1]}"
  debug "received ping: %s" "${params[0]}"
}

on_PONG() {
  debug "received pong: %s" "${params[1]}"
}

on_PRIVMSG() {
  info "<%s/%s> %s" "$from" "${params[0]}" "${params[1]}"
}

on_QUIT() {
  info "%s has disconnected: %s" "$from" "${params[0]}"
}

on_001() {
  info %s "${params[1]}"

  if [[ $chan ]]; then
    join "$chan"
  fi

  {
    debug "timer pid is %d" "$BASHPID"

    while true; do
      kill -ALRM "$$"
      sleep 10
    done
  } &

  ping_pid=$!
  nick=${params[0]}
  registered=yes
  who "$nick" %%uht,42
}

on_002() {
  info %s "${params[1]}"
}

on_003() {
  info %s "${params[1]}"
}

on_004() {
  debug "%s " "${params[@]:1}"
}

declare -A isupport

on_005() {
  local param key value

  for param in "${params[@]:1:${#params[@]}-2}"; do
    IFS== read -r key value <<< "$param"
    isupport[$key]=$value
    debug "isupport: %s = %s" "$key" "$value"
  done
}

on_250() {
  info %s "${params[1]}"
}

on_251() {
  info %s "${params[1]}"
}

on_252() {
  info "There are %d operators online" "${params[1]}"
}

on_253() {
  info "There are %d unknown connections" "${params[1]}"
}

on_254() {
  info "There are %d channels formed" "${params[1]}"
}

on_255() {
  info %s "${params[1]}"
}

on_265() {
  info %s "${params[3]}"
}

on_266() {
  info %s "${params[3]}"
}

on_315() {
  debug "end of WHO for %s" "${params[1]}"
}

on_332() {
  info "topic for %s is %s" "${params[1]}" "${params[2]}"
}

on_333() {
  local date
  printf -v date '%(%c)T' "${params[3]}"
  info "topic for %s set by %s at %s" "${params[1]}" "${params[2]}" "$date"
}

on_353() {
  info "members of %s: %s" "${params[2]}" "${params[3]}"
}

on_354() {
  if (( ${params[1]} == 42 )); then
    debug "received the identifying who"
    ident=${params[2]} host=${params[3]}
    debug "ident=%s host=%s" "$ident" "$host"
  fi
}

on_366() {
  debug "%s: end of NAMES list" "${params[1]}"
}

on_372() {
  info %s "${params[1]}"
}

on_375() {
  debug %s "${params[1]}"
}

on_376() {
  debug %s "${params[1]}"
}

on_433() {
  info "somebody is already using %s" "${params[1]}"

  if [[ $registered = no ]]; then
    nick "${nick}_"
  fi
}

on_473() {
  error "%s: %s" "${params[1]}" "${params[2]}"
}

###
# irc send code
###

join() {
  send "JOIN %s" "$1"
}

nick() {
  send "NICK %s" "$1"
}

notice() {
  if [[ -v host ]]; then
    local msg_len msg=$2
    (( msg_len = 494 - (${#nick} + ${#ident} + ${#host} + ${#1}) ))
    debug "max message length is %d" "$msg_len"

    while (( ${#msg} > msg_len )); do
      send "NOTICE %s :"$'\xe2\x80\x8b'"%s" "$1" "${msg:0:$msg_len}"
      info "[%s/%s] %s" "$nick" "$1" "${msg:0:$msg_len}"
      msg=${msg:$msg_len}
    done
  fi

  send "NOTICE %s :%s" "$1" "$2"
  info "[%s/%s] %s" "$nick" "$1" "$2"
}

part() {
  if (( $# )); then
    if (( $# > 1 )); then
      send "PART $1 :$2"
    else
      send "PART $1"
    fi
  fi
}

ping() {
  send "PING :%s" "$1"
}

pong() {
  send "PONG %s" "$1"
}

privmsg() {
  if [[ -v host ]]; then
    local msg_len msg=$2
    (( msg_len = 493 - (${#nick} + ${#ident} + ${#host} + ${#1}) ))
    debug "max message length is %d" "$msg_len"

    while (( ${#msg} > msg_len )); do
      send "PRIVMSG %s :"$'\xe2\x80\x8b'"%s" "$1" "${msg:0:$msg_len}"
      info "<%s/%s> %s" "$nick" "$1" "${msg:0:$msg_len}"
      msg=${msg:$msg_len}
    done
  fi

  send "PRIVMSG %s :"$'\xe2\x80\x8b'"%s" "$1" "$msg"
  info "<%s/%s> %s" "$nick" "$1" "$msg"
}

quit() {
  if (( $# )); then
    send "QUIT :%s" "$1"
  else
    send QUIT
  fi
}

user() {
  send "USER %s 0 * :%s" "$ident" "$realname"
}

who() {
  if (( $# > 1 )); then
    send "WHO %s %s" "$1" "$2"
  else
    send "WHO %s" "$1"
  fi
}

###
# app hooks
##

hook_pre_PRIVMSG_CTCP() {
  if [[ ${params[1]} != $'\x01'*$'\x01' ]]; then
    return 0
  fi

  local cmd msg
  cmd=${params[1]#$'\x01'} cmd=${cmd%% *}
  msg=${params[1]#* } msg=${msg%$'\x01'}

  if [[ ${cmd^^} = ACTION ]]; then
    if [[ ${params[0]:0:1} = \# ]]; then
      info "ctcp: %s: %s %s" "${params[0]}" "$from" "$msg"
    else
      info "privately, %s %s" "$from" "$msg"
    fi

    return 1
  elif [[ ${params[0]:0:1} = \# ]]; then
    info "ctcp: %s has requested %s in %s" "$from" "${cmd^^}" "${params[0]}"
    return 1
  fi

  info "ctcp: sending %s to %s" "${cmd^^}" "$from"

  case ${cmd^^} in
  CLIENTINFO)
    notice "$from" $'\x01'"CLIENTINFO ACTION CLIENTINFO PING SOURCE TIME VERSION"$'\x01'
    ;;
  PING)
    local msg
    msg=${params[1]#* } msg=${msg%$'\x01'}
    notice "$from" $'\x01'"PING $msg"$'\x01'
    ;;
  SOURCE)
    notice "$from" $'\x01'"SOURCE https://ahti.space/git/uplime/rowbot"$'\x01'
    ;;
  TIME)
    notice "$from" $'\x01'"TIME time for you to get a watch"$'\x01'
    ;;
  VERSION)
    notice "$from" $'\x01'"VERSION rowbot v2"$'\x01'
  esac

  return 1
}

hook_post_PRIVMSG_factoids() {
  if [[ ${params[0]:0:1} != \# ]]; then
    return 0
  elif [[ ${words[0]} = "$trigger"* ]]; then
    case ${words[0]:${#trigger}} in
    is)
      if (( ${#words[@]} < 3 )); then
        return 0
      fi

      local key val
      key=${params[1]#*"$trigger"is} key=${key# }
      val=${key#* } key=${key%% *}

      info "%s said in %s to remember %s as %s" "$from" "${params[0]}" "$key" "$val"
      privmsg "${params[0]}" "I'm sure I'll remember that."
      mkdir -p "$fact_root"/"${params[0]}"
      printf %s "$val" > "$fact_root"/"${params[0]}"/"$key"
      ;;
    isnt)
      if (( ${#words[@]} < 2 )); then
        return 0
      fi

      local key
      key=${params[1]#*"$trigger"isnt} key=${key# }

      if [[ -f $fact_root/${params[0]}/$key ]]; then
        info "%s said in %s to delete %s" "$from" "${params[0]}" "$key"
        privmsg "${params[0]}" "I forgot what that was anyways."
        rm -f "$fact_root"/"${params[0]}"/"$key"
      fi
      ;;
    ls)
      local facts=( "$fact_root"/"${params[0]}"/* )
      privmsg "${params[0]}" "${facts[*]##*/}"
      ;;
    *)
      local key=${words[0]:${#trigger}}

      if [[ -f $fact_root/${params[0]}/$key ]]; then
        local msg=$(<"$fact_root"/"${params[0]}"/"$key")

        if (( ${#words[@]} > 1 )) && [[ ${words[1]} = \> ]]; then
          local target
          target=${params[1]#*\>} target=${target# } target=${target% }
          privmsg "${params[0]}" "$target: $msg"
        else
          privmsg "${params[0]}" "$from: $msg"
        fi
      fi
    esac
  fi
}

hook_post_PRIVMSG_control_panel() {
  if [[ ${words[0]} = "$trigger"* ]]; then
    if [[ $from != $owner && $dev != yes ]]; then
      return 0
    fi

    local to=${params[0]}

    if [[ ${params[0]:0:1} != \# ]]; then
      to=$from
    fi

    case ${words[0]:${#trigger}} in
    raw)
      local cmd
      cmd=${params[1]#"$trigger"raw} cmd=${cmd# }
      info "%s is executing command: %s" "$from" "$cmd"
      send "$cmd"
      ;;
    join)
      join "${words[1]}"
      privmsg "$to" "joined ${words[1]}"
      ;;
    reload)
      export IN_SOCK=$in_sock OUT_SOCK=$out_sock LOG_FD=$log DEV=$dev
      export RELOAD_TO=$to TRIGGER=$trigger LOG_LEVEL=$level
      export NICK=$nick IDENT=$ident REGISTERED=$registered

      if [[ $keep_trying = yes ]]; then
        export KEEP_TRYING=yes DESIRED=$desired_nick
      fi

      if [[ -v host ]]; then
        export HOST=$host
      fi

      if [[ $tls = yes ]]; then
        export SOCK_DIR=$sock_dir
        export TLS_PID=$tls_pid
      fi

      if [[ -v ping_pid ]]; then
        export PING_pid=$ping_pid
      fi

      privmsg "$to" "reloading..."
      exec "${original_args[@]}" --reload
      ;;
    level)
      level=${words[1]}
      privmsg "$to" "log level is now set to $level"
      ;;
    dev)
      if [[ $dev = yes ]]; then
        dev=no
        privmsg "$to" "developer status disabled"
      else
        dev=yes
        privmsg "$to" "developer status enabled"
      fi
      ;;
    dev\?)
      if [[ $dev = yes ]]; then
        privmsg "$to" "developer status is enabled"
      else
        privmsg "$to" "developer status is disabled"
      fi
      ;;
    trigger)
      if (( ${#words[@]} > 1 )); then
        trigger=${words[1]}
        privmsg "$to" "trigger is now $trigger"
      fi
      ;;
    msg)
      if (( ${words[@]} > 2 )); then
        privmsg "${words[1]}" "${words[*]:2}"
        privmsg "$to" "sent message to ${words[1]}"
      fi
      ;;
    cycle)
      if [[ ${to:0:1} = \# ]]; then
        privmsg "$to" "cycling channel $to"
        part "$to" "be back soon!"
        join "$to"
      fi
    esac
  fi
}

hook_post_433_alternick() {
  if [[ -z $desired_nick && $registered = no ]]; then
    desired_nick=${params[1]}
    keep_trying=yes
  fi
}

hook_post_NICK_alternick() {
  if [[ ${params[0]} = $desired_nick ]]; then
    keep_trying=no
    info "obtained nick %s" "$desired_nick"
  fi
}

###
# driver
###

if [[ $reload = yes ]]; then
  privmsg "$RELOAD_TO" done.
else
  registered=no
  info "rowbot's pid is %d" "$$"
  nick "$nick"
  user "$ident" "$realname"
fi

while recv line; do
  params=( )
  has_words=no
  orig_line=$line

  if [[ ${line:0:1} = : ]]; then
    src=${line%% *} src=${src#:}
    line=${line#:"$src"} line=${line# }
    from=${src%@*} ident=${from#*!}
    from=${from%!*} host=${src#*@}
  fi

  cmd=${line%% *}
  line=${line#"$cmd"}
  line=${line# }

  while [[ $line ]]; do
    if [[ ${line:0:1} = : ]]; then
      params+=("${line:1}")
      line=""
      has_words=yes
    else
      param=${line%% *}
      params+=("$param")
      line=${line#"$param"} line=${line# }
    fi
  done

  if [[ $has_words = yes ]]; then
    read -ra words <<< "${params[@]:(-1)}"
  else
    words=( )
  fi

  skip_handler=0

  while IFS= read -r hook; do
    "$hook"
    (( skip_handler |= $? ))
  done < <(compgen -A function "hook_pre_${cmd^^}_")

  if hash "on_${cmd^^}" 2>/dev/null; then
    if (( ! skip_handler )); then
      "on_${cmd^^}"
    else
      debug "handler for %s was skipped" "${cmd^^}"
    fi
  else
    warn "unhandled line: %s" "$orig_line"
  fi

  while IFS= read -r hook; do
    "$hook"
  done < <(compgen -A function "hook_post_${cmd^^}_")
done