#!/usr/bin/env bash
set -euo pipefail

source "$(dirname "${BASH_SOURCE[0]}")/worktree-common.sh"

port_in_use() {
  lsof -nP -iTCP:"$1" -sTCP:LISTEN &>/dev/null
}

if [[ -z "${WM_SLOT:-}" ]]; then
  # Scan .env.local files of existing worktrees to find which slots are claimed,
  # then pick the lowest free slot. This avoids collisions when worktrees are
  # removed and new ones created (position-based indexing would re-use slots
  # still held by surviving worktrees).
  used_slots=()
  current_dir="$(pwd)"
  while IFS= read -r wt_path; do
    [[ "$wt_path" == "$current_dir" ]] && continue
    if [[ -f "$wt_path/.env.local" ]]; then
      bp=$(grep '^BACKEND_PORT=' "$wt_path/.env.local" | cut -d= -f2 || true)
      if [[ -n "$bp" && "$bp" -gt 8000 ]]; then
        used_slots+=("$(( (bp - 8000) / 10 ))")
      fi
    fi
  done < <(git worktree list --porcelain | sed -n 's/^worktree //p')

  # Find lowest available slot (slot 0 = 8000/3000 is reserved for main)
  WM_SLOT=1
  while [[ " ${used_slots[*]:-} " == *" $WM_SLOT "* ]]; do
    ((WM_SLOT++))
  done
  echo "Auto-assigned slot $WM_SLOT (used: ${used_slots[*]:-none})"
fi

# Slot-based: predictable ports for SSH forwarding
# Slot 0 = 8000/3000, slot 1 = 8010/3010, slot 2 = 8020/3020, etc.
backend_port=$((8000 + WM_SLOT * 10))
frontend_port=$((3000 + WM_SLOT * 10))

if port_in_use "$backend_port" || port_in_use "$frontend_port"; then
  echo "WARNING: Slot $WM_SLOT ports ($backend_port/$frontend_port) already in use" >&2
fi

# Generate .env.local with port overrides
cat > .env.local <<EOF
BACKEND_PORT=$backend_port
FRONTEND_PORT=$frontend_port
REMOTE=http://localhost:$backend_port
EOF

if [[ -n "${CARGO_FEATURES:-}" ]]; then
  echo "CARGO_FEATURES=$CARGO_FEATURES" >> .env.local
fi

echo "Created .env.local with ports: backend=$backend_port, frontend=$frontend_port"
wm_shared_post_create "$(pwd)"