#!/usr/bin/env bash
set -euo pipefail
#
# session-status.sh — Check agent session health
#
# Usage:
#   session-status.sh [--project <path>] [--format table|json]
#
# Exit codes:
#   0 = running
#   2 = stale (recently died)
#   3 = dead (no longer running)
#   4 = no session

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/_lib.sh"

# ─── Parse arguments ─────────────────────────────────────────────────────────

PROJECT="."
FORMAT="table"

while [[ $# -gt 0 ]]; do
  case "$1" in
    --project)  PROJECT="$2"; shift 2 ;;
    --format)   FORMAT="$2"; shift 2 ;;
    -h|--help)
      echo "Usage: session-status.sh [--project <path>] [--format table|json]"
      exit 0
      ;;
    *) echo "Unknown option: $1" >&2; exit 1 ;;
  esac
done

_require_jq

# ─── Check session lock ─────────────────────────────────────────────────────

lock_data=""
if ! lock_data="$(session_lock_read "$PROJECT")"; then
  if [[ "$FORMAT" == "json" ]]; then
    echo '{"status":"no-session"}'
  else
    echo -e "${C_DIM}No active session.${C_RESET}"
  fi
  exit 4
fi

# Parse lock
session_id="$(echo "$lock_data" | jq -r '.session_id // "unknown"')"
runtime="$(echo "$lock_data" | jq -r '.runtime // "unknown"')"
pid="$(echo "$lock_data" | jq -r '.pid // 0')"
started_at="$(echo "$lock_data" | jq -r '.started_at // ""')"
milestone_id="$(echo "$lock_data" | jq -r '.milestone_id // ""')"

# ─── Determine status ───────────────────────────────────────────────────────

status="unknown"
exit_code=1

if is_pid_alive "$pid"; then
  status="running"
  exit_code=0
else
  # PID is dead — check how recently
  last_act="$(last_activity_time "$PROJECT")"
  now="$(epoch_now)"
  age=$(( now - last_act ))

  if (( age < STALE_THRESHOLD )); then
    status="stale"
    exit_code=2
  elif (( age < DEAD_THRESHOLD )); then
    status="stale"
    exit_code=2
  else
    status="dead"
    exit_code=3
  fi
fi

# ─── Gather supplementary info ──────────────────────────────────────────────

duration_secs=0
if [[ -n "$started_at" ]]; then
  start_epoch="$(iso_to_epoch "$started_at")"
  now="$(epoch_now)"
  duration_secs=$(( now - start_epoch ))
fi

last_act="$(last_activity_time "$PROJECT")"

# Current milestone from mission.json
current_ms=""
if [[ -f "$(mission_path "$PROJECT")" ]]; then
  current_ms="$(current_milestone_id "$PROJECT")"
  if [[ -n "$current_ms" ]]; then
    ms_name="$(milestone_name "$PROJECT" "$current_ms")"
    [[ -n "$ms_name" ]] && current_ms="$current_ms ($ms_name)"
  fi
fi

# Next task from TASKS.md
next_task="$(find_next_task "$PROJECT")"

# ─── Output ──────────────────────────────────────────────────────────────────

if [[ "$FORMAT" == "json" ]]; then
  jq -n \
    --arg status "$status" \
    --arg session_id "$session_id" \
    --arg runtime "$runtime" \
    --arg pid "$pid" \
    --arg started_at "$started_at" \
    --arg duration "$duration_secs" \
    --arg milestone "$current_ms" \
    --arg next_task "$next_task" \
    --arg last_activity "$last_act" \
    '{
      status: $status,
      session_id: $session_id,
      runtime: $runtime,
      pid: ($pid | tonumber),
      started_at: $started_at,
      duration_seconds: ($duration | tonumber),
      milestone: $milestone,
      next_task: $next_task,
      last_activity_epoch: ($last_activity | tonumber)
    }'
else
  # Color the status
  case "$status" in
    running) status_color="${C_GREEN}RUNNING${C_RESET}" ;;
    stale)   status_color="${C_YELLOW}STALE${C_RESET}" ;;
    dead)    status_color="${C_RED}DEAD${C_RESET}" ;;
    *)       status_color="$status" ;;
  esac

  echo ""
  echo -e "  Session Status: $status_color ($runtime)"
  echo -e "  ${C_CYAN}Session ID:${C_RESET}    $session_id"
  echo -e "  ${C_CYAN}Started:${C_RESET}       $started_at ($(format_duration "$duration_secs"))"
  echo -e "  ${C_CYAN}PID:${C_RESET}           $pid"
  [[ -n "$current_ms" ]] && echo -e "  ${C_CYAN}Milestone:${C_RESET}     $current_ms"
  [[ -n "$next_task" ]] && echo -e "  ${C_CYAN}Next task:${C_RESET}     $next_task"
  echo -e "  ${C_CYAN}Last activity:${C_RESET} $(format_ago "$last_act")"
  echo ""

  if [[ "$status" == "stale" || "$status" == "dead" ]]; then
    echo -e "  ${C_YELLOW}Session is no longer running.${C_RESET}"
    echo "  Recovery: mosaic coord resume"
    echo "  Continue: mosaic coord continue"
    echo ""
  fi
fi

exit "$exit_code"