#!/usr/bin/env bash

set -e

projects_dir=$HOME/Projects

list_projects() {
  local projects=() dir relative clone worktree projects_real

  # git reports symlink-resolved paths, which may not match how we spell it.
  projects_real=$(cd "$projects_dir" 2>/dev/null && pwd -P) ||
    projects_real=$projects_dir

  for dir in "$projects_dir"/*/*/; do
    [ -d "$dir" ] || continue
    relative="${dir#$projects_dir/}"
    relative="${relative%/}"

    if [[ "$relative" != *@* ]]; then
      projects+=("$relative")
      continue
    fi

    # `repo@branch` holds the worktrees of the `repo` clone, one level deeper
    # per `/` in the branch name. Asking git beats a scan deep enough to reach
    # them, which walks every working tree under $projects_dir. `worktree list`
    # also names the clone itself, already added above; sort -u collapses it.
    clone="$projects_dir/${relative%%@*}"
    while IFS= read -r worktree; do
      case $worktree in
        "$projects_dir"/*) worktree=${worktree#"$projects_dir"/} ;;
        "$projects_real"/*) worktree=${worktree#"$projects_real"/} ;;
        *) continue ;;
      esac
      # Registered but deleted worktrees linger until `git worktree prune`.
      [ -d "$projects_dir/$worktree" ] || continue
      projects+=("$worktree")
    done < <(git -C "$clone" worktree list --porcelain 2>/dev/null |
      sed -n 's|^worktree ||p')
  done

  printf '%s\n' "${projects[@]}" | sort -u
}

# Second pass: runs inside the popup, on the list the first pass built.
if [[ "${1:-}" == --pick ]]; then
  listfile=$2
  trap 'rm -f "$listfile"' EXIT

  project=$(
    fzf --layout=reverse --info=hidden --border=rounded --cycle < "$listfile"
  ) || exit 0
  [ -n "$project" ] || exit 0

  # In a session for this same project the slug just repeats the session name,
  # so use the branch instead. tmux rewrote `.` and `:` in the session name.
  window_name=$project
  session=$(tmux display -p '#S')
  root=${project%%@*}
  if [ "${root//[.:]/_}" = "$session" ]; then
    branch=$(git -C "$projects_dir/$project" symbolic-ref --short HEAD 2>/dev/null ||
      git -C "$projects_dir/$project" rev-parse --short HEAD 2>/dev/null || true)
    window_name=${branch:-$project}
  fi

  tmux new-window -n "$window_name" -c "$projects_dir/$project"
  ~/.local/share/tmux/layouts/window-auto
  exit
fi

# First pass: size the popup, then re-launch inside it. fzf has no width of its
# own — it fills the popup — so the popup width is what we scale.
listfile=$(mktemp)
list_projects > "$listfile"

longest=0
while IFS= read -r line; do
  if (( ${#line} > longest )); then
    longest=${#line}
  fi
done < "$listfile"

# run-shell owns no client, so resolve the one that triggered us: without -c
# the popup gets no tty and fzf can't draw.
client=$(tmux display -p '#{client_name}')
cols=$(tmux display -p -c "$client" '#{client_width}')

min=60
max=$(( cols * 90 / 100 ))
# 6 = border (2) + pointer gutter (2) + scrollbar (1) + breathing room.
width=$(( longest + 6 ))
(( width < min )) && width=$min
(( width > max )) && width=$max

flags=(-c "$client" -w "$width" -h 10)
if ~/.config/tmux/check-version.sh ">= 3.3"; then
  flags+=(-B)
fi

tmux display-popup "${flags[@]}" -E "'$0' --pick '$listfile'"