#!/usr/bin/env bash
# dt — gestionnaire de sessions claude-dans-dtach (1 session = 1 claude = 1 socket)
# Sockets dans ~/.dtach/. La creation se fait via l'alias `cc` (voir plus bas),
# pas ici : dt ne gere que listing / rattachement / kill.
#
#   dt ls            lister (nom, age, dossier, commande)
#   dt at <nom>      rattacher une session
#   dt kill <nom>    tuer une session
#   dt --raw         listing TSV (pour fzf)
#   dt sock <nom>    imprime le chemin du socket (utilitaire interne)
#
# Detacher une session attachee : Ctrl-\
#
# CREATION (a mettre dans ~/.bashrc) :
#   dtach_claude() { dtach -c "$HOME/.dtach/${1:-claude-$(date +%H%M%S)}" -e '^\' claude; }
#   alias cc='dtach_claude'
#   # usage : cd ~/projets/seo && cc seo
set -uo pipefail

DTDIR="${DTACH_DIR:-$HOME/.dtach}"
mkdir -p "$DTDIR"
now=$(date +%s)

# PID(s) du process dtach pour ce socket, via la cmdline (ss ne liste pas les
# sockets dtach de maniere fiable selon la version). Matche -c/-n/-A/-N.
_pids_for_socket() {
  local sock="$1"
  pgrep -f -- "dtach -[cnAN] $sock" 2>/dev/null | sort -u
}

_cwd_of() { readlink -f "/proc/$1/cwd" 2>/dev/null; }

# Heure de demarrage REELLE du process (fiable, immuable), en epoch.
_starttime_of() {
  local ls; ls=$(ps -o lstart= -p "$1" 2>/dev/null) || return
  [ -n "$ls" ] && date -d "$ls" +%s 2>/dev/null
}

_age() {
  local epoch="${1:-$now}"
  # garde-fou : si epoch n'est pas numerique, age=0
  [[ "$epoch" =~ ^[0-9]+$ ]] || epoch="$now"
  local age="$(( now - epoch ))"
  (( age < 0 )) && age=0
  if   (( age<60 ));   then echo "${age}s"
  elif (( age<3600 )); then echo "$(( age/60 ))m"
  elif (( age<86400));then echo "$(( age/3600 ))h$(( (age%3600)/60 ))m"
  else                      echo "$(( age/86400 ))j$(( (age%86400)/3600 ))h"; fi
}

# Une ligne TSV par session vivante. Nettoie les sockets morts au passage.
emit_raw() {
  shopt -s nullglob
  local sock name pids master cwd start
  for sock in "$DTDIR"/*; do
    [ -S "$sock" ] || continue
    name=$(basename "$sock")
    pids=$(_pids_for_socket "$sock")
    if [ -z "$pids" ]; then rm -f "$sock"; continue; fi   # orphelin -> menage
    master=$(echo "$pids" | head -1)
    cwd=$(_cwd_of "$master");        cwd="${cwd:-?}"
    start=$(_starttime_of "$master"); start="${start:-$now}"
    # colonnes : NOM(cache pour fzf) TAB DOSSIER TAB AGE
    printf '%s\t%s\t%s\n' "$name" "${cwd/#$HOME/\~}" "$(_age "$start")"
  done
}

cmd_at() {
  local name="${1:?nom requis}"; local sock="$DTDIR/$name"
  [ -S "$sock" ] || { echo "Session '$name' introuvable."; return 1; }
  exec dtach -a "$sock" -e '^\'
}

cmd_kill() {
  local name="${1:?nom requis}"; local sock="$DTDIR/$name"
  [ -S "$sock" ] || { echo "Session '$name' introuvable."; return 1; }
  local master; master=$(_pids_for_socket "$sock" | head -1)
  [ -n "$master" ] && kill "$master" 2>/dev/null
  rm -f "$sock"
  echo "Session '$name' tuee."
}

cmd_sock() { echo "$DTDIR/${1:?nom requis}"; }

cmd_ls() {
  local rows; rows=$(emit_raw)
  if [ -z "$rows" ]; then echo "Aucune session dtach."; return 0; fi
  printf '\n  \033[1;36mSessions claude\033[0m\n\n'
  printf '  \033[2m%-40s %s\033[0m\n' DOSSIER AGE
  printf '%s\n' "$rows" | while IFS=$'\t' read -r name cwd age; do
    printf '  \033[34m%-40s\033[0m \033[33m%s\033[0m\n' "$cwd" "$age"
  done
  printf '\n'
}

case "${1:-}" in
  ls)    shift; cmd_ls "$@" ;;
  at)    shift; cmd_at "$@" ;;
  kill)  shift; cmd_kill "$@" ;;
  sock)  shift; cmd_sock "$@" ;;
  --raw) emit_raw ;;
  ""|-h|--help) sed -n '2,18p' "$0" | sed 's/^# \?//' ;;
  *) echo "Commande inconnue: $1"; sed -n '2,18p' "$0" | sed 's/^# \?//'; exit 1 ;;
esac