#!/usr/bin/env bash

set -e

projects_dir=$HOME/Projects

# Print the sorted, de-duplicated list of selectable projects.
list_projects() {
  local projects=() dir relative clone worktree projects_real

  # git reports symlink-resolved paths, which need not spell $projects_dir the
  # way we do, so keep the resolved form around to match them against too.
  projects_real=$(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%/}"

    # All depth-2 directories without @ are included unconditionally
    if [[ "$relative" != *@* ]]; then
      projects+=("$relative")
      continue
    fi

    # A `repo@branch` directory is the parent of the worktrees hanging off the
    # `repo` clone, nested one level deeper per `/` in the branch name. Ask
    # that clone which worktrees it has instead of scanning: git already knows,
    # whereas a scan deep enough to reach them has to walk every working tree
    # under $projects_dir to find a handful of entries. Submodules aren't
    # worktrees, so they never turn up and need no filtering out. `git worktree
    # list` also names the clone itself, which the branch above already added —
    # the final sort -u collapses the pair.
    clone="$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. Read the list the first pass already
# built (so the directory scan only happens once) and open the selection.
if [[ "${1:-}" == --pick ]]; then
  listfile=$2
  trap 'rm -f "$listfile"' EXIT

  # Cancelling fzf (Esc/^C) exits non-zero; treat it as "no selection" and
  # leave quietly, rather than letting the status propagate out of the popup
  # and print '...project.sh returned 130' in the parent pane.
  project=$(
    fzf --layout=reverse --info=hidden --border=rounded --cycle < "$listfile"
  ) || exit 0
  [ -n "$project" ] || exit 0

  # Inside a session for this same project, e.g. one created by `session -p`,
  # the slug only repeats the session name, so name the window after the branch
  # checked out there instead — a worktree's whole identity. Everything up to
  # the `@` is the clone the worktrees hang off, and tmux rewrote `.` and `:` in
  # the session name, so match both before comparing.
  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: scan once, size a popup to fit the longest project name, then
# re-launch ourselves 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"

# We're launched from run-shell, which owns no client, so resolve the client
# that triggered us. It both anchors the popup (-c, without which the popup
# gets no tty and fzf can't draw) and gives the terminal width for the cap.
client=$(tmux display -p '#{client_name}')
cols=$(tmux display -p -c "$client" '#{client_width}')

# Clamp between the original fixed width and 90% of the terminal. In between,
# pad for fzf's chrome: rounded border (2) + pointer gutter (2) + scrollbar (1)
# + a column of breathing room.
min=60
max=$(( cols * 90 / 100 ))
width=$(( longest + 6 ))
(( width < min )) && width=$min
(( width > max )) && width=$max

flags=(-c "$client" -w "$width" -h 10)
# Match the borderless popup the keybinding used on tmux >= 3.3.
if ~/.config/tmux/check-version.sh ">= 3.3"; then
  flags+=(-B)
fi

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