#!/bin/bash
# Launch tmux session with an LLM in fzf-selected project directories

SESSION="ai"

# Switch to or attach to the session
attach_session() {
  if [ -n "$TMUX" ]; then
    tmux switch-client -t "$SESSION"
  else
    tmux attach-session -t "$SESSION"
  fi
}

# Attach directly to existing session
if [ "$1" = "--attach" ]; then
  if ! tmux has-session -t "$SESSION" 2>/dev/null; then
    echo "No $SESSION session to attach to." >&2
    exit 1
  fi
  attach_session
  exit 0
fi

# Dependency checks
for cmd in fzf tmux claude; do
  if ! command -v "$cmd" &>/dev/null; then
    echo "Error: $cmd is not installed" >&2
    exit 1
  fi
done

# Claude command — separated for safe editing
AI_CMD="claude"
AI_INSTRUCTIONS='Read docs/protocols.org and follow all instructions.'

# Create a window in the session and launch claude; prints window ID
create_window() {
  local dir="$1" name="$2" wid
  wid=$(tmux new-window -t "$SESSION" -n "$name" -c "$dir" -P -F '#{window_id}')
  sleep 0.1
  tmux send-keys -t "$wid" "$AI_CMD \"$AI_INSTRUCTIONS\"" Enter
  echo "$wid"
}

# Read fzf selections into the 'selected' array
read_selections() {
  selected=()
  while IFS= read -r line; do
    selected+=("$line")
  done <<<"$1"
}

# Build candidate directory list
build_candidates() {
  candidates=()
  [ -d "$HOME/.emacs.d" ] && candidates+=("~/.emacs.d")
  if [ -d "$HOME/code" ]; then
    while IFS= read -r d; do
      candidates+=("~/${d#"$HOME"/}")
    done < <(find "$HOME/code" -maxdepth 1 -mindepth 1 -type d | sort)
  fi
  if [ -d "$HOME/projects" ]; then
    while IFS= read -r d; do
      candidates+=("~/${d#"$HOME"/}")
    done < <(find "$HOME/projects" -maxdepth 1 -mindepth 1 -type d | sort)
  fi
}

# Sort windows alphabetically by name, shells last
sort_windows() {
  local windows shells projects
  windows=$(tmux list-windows -t "$SESSION" -F '#{window_name}'$'\t''#{window_id}')
  shells=$(echo "$windows" | grep -iE '^(bash|zsh|fish|sh)'$'\t' | sort -t$'\t' -k1,1f)
  projects=$(echo "$windows" | grep -viE '^(bash|zsh|fish|sh)'$'\t' | sort -t$'\t' -k1,1f)
  local all
  all=$(printf '%s\n' "$shells" "$projects" | sed '/^$/d')

  # Move all to high temp indices to avoid collisions
  local i=900
  while IFS=$'\t' read -r _name wid; do
    tmux move-window -s "$wid" -t "$SESSION:$i"
    ((i++))
  done <<<"$all"

  # Place shells at 0, projects from 1
  i=0
  if [ -n "$shells" ]; then
    while IFS=$'\t' read -r _name wid; do
      tmux move-window -s "$wid" -t "$SESSION:$i"
      ((i++))
    done <<<"$shells"
  fi
  i=1
  if [ -n "$projects" ]; then
    while IFS=$'\t' read -r _name wid; do
      tmux move-window -s "$wid" -t "$SESSION:$i"
      ((i++))
    done <<<"$projects"
  fi
}

# If session exists, add new windows to it
if tmux has-session -t "$SESSION" 2>/dev/null; then
  # Get existing window names to filter duplicates
  existing=$(tmux list-windows -t "$SESSION" -F '#{window_name}')

  build_candidates

  # Filter out candidates that already have a window open
  filtered=()
  for c in "${candidates[@]}"; do
    name="$(basename "${c/#\~/$HOME}")"
    if ! echo "$existing" | grep -qxF "$name"; then
      filtered+=("$c")
    fi
  done

  if [ ${#filtered[@]} -eq 0 ]; then
    echo "All projects already have windows open."
  else
    selections=$(printf '%s\n' "${filtered[@]}" | fzf --multi --height=70% --reverse)

    if [ -n "$selections" ]; then
      read_selections "$selections"

      first_wid=""
      for entry in "${selected[@]}"; do
        dir="${entry/#\~/$HOME}"
        name="$(basename "$dir")"
        wid=$(create_window "$dir" "$name")
        [ -z "$first_wid" ] && first_wid="$wid"
      done

      sort_windows
      tmux select-window -t "$first_wid"
    fi
  fi

  attach_session
  exit 0
fi

# New session: select projects and create session
build_candidates

selections=$(printf '%s\n' "${candidates[@]}" | fzf --multi --height=70% --reverse)
[ -z "$selections" ] && exit 0

read_selections "$selections"

# Create session with first selection
first="${selected[0]}"
dir="${first/#\~/$HOME}"
name="$(basename "$dir")"
first_wid=$(tmux new-session -d -s "$SESSION" -n "$name" -c "$dir" -P -F '#{window_id}')
tmux send-keys -t "$first_wid" "$AI_CMD \"$AI_INSTRUCTIONS\"" Enter

# Create remaining windows
for entry in "${selected[@]:1}"; do
  dir="${entry/#\~/$HOME}"
  name="$(basename "$dir")"
  create_window "$dir" "$name" > /dev/null
done

# Sort windows and select first
sort_windows
tmux select-window -t "$SESSION:1"
attach_session