#!/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
runtime_cmd="$(coord_launch_command)"
run_cmd="$(coord_run_command)"

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

lock_data=""
if ! lock_data="$(session_lock_read "$PROJECT")"; then
  # No active session — but check if a mission exists
  mp="$(mission_path "$PROJECT")"
  if [[ -f "$mp" ]]; then
    m_status="$(jq -r '.status // "inactive"' "$mp")"
    m_name="$(jq -r '.name // "unnamed"' "$mp")"
    m_id="$(jq -r '.mission_id // ""' "$mp")"
    m_total="$(jq '.milestones | length' "$mp")"
    m_done="$(jq '[.milestones[] | select(.status == "completed")] | length' "$mp")"
    m_current="$(jq -r '[.milestones[] | select(.status == "active" or .status == "pending")][0].name // "none"' "$mp")"

    # Task counts if TASKS.md exists
    task_json="$(count_tasks_md "$PROJECT")"
    t_total="$(echo "$task_json" | jq '.total')"
    t_done="$(echo "$task_json" | jq '.done')"
    t_pending="$(echo "$task_json" | jq '.pending')"
    t_inprog="$(echo "$task_json" | jq '.in_progress')"

    if [[ "$FORMAT" == "json" ]]; then
      jq -n \
        --arg status "no-session" \
        --arg mission_status "$m_status" \
        --arg mission_name "$m_name" \
        --arg mission_id "$m_id" \
        --argjson milestones_total "$m_total" \
        --argjson milestones_done "$m_done" \
        --argjson tasks_total "$t_total" \
        --argjson tasks_done "$t_done" \
        '{
          status: $status,
          mission: {
            status: $mission_status,
            name: $mission_name,
            id: $mission_id,
            milestones_total: $milestones_total,
            milestones_done: $milestones_done,
            tasks_total: $tasks_total,
            tasks_done: $tasks_done
          }
        }'
    else
      echo ""
      echo -e "  ${C_DIM}No active agent session.${C_RESET}"
      echo ""

      # Mission info
      case "$m_status" in
        active)    ms_color="${C_GREEN}ACTIVE${C_RESET}" ;;
        paused)    ms_color="${C_YELLOW}PAUSED${C_RESET}" ;;
        completed) ms_color="${C_CYAN}COMPLETED${C_RESET}" ;;
        *)         ms_color="${C_DIM}${m_status}${C_RESET}" ;;
      esac

      echo -e "  ${C_BOLD}Mission:${C_RESET}       $m_name"
      echo -e "  ${C_CYAN}Status:${C_RESET}        $ms_color"
      echo -e "  ${C_CYAN}ID:${C_RESET}            $m_id"
      echo -e "  ${C_CYAN}Milestones:${C_RESET}    $m_done / $m_total completed"
      [[ "$m_current" != "none" ]] && echo -e "  ${C_CYAN}Current:${C_RESET}       $m_current"

      if (( t_total > 0 )); then
        echo -e "  ${C_CYAN}Tasks:${C_RESET}         $t_done / $t_total done ($t_pending pending, $t_inprog in-progress)"
      fi
      echo ""

      if [[ "$m_status" == "active" || "$m_status" == "paused" ]]; then
        echo -e "  ${C_BOLD}Next steps:${C_RESET}"
        echo "    $run_cmd                 Auto-generate context and launch"
        echo "    mosaic coord continue     Generate continuation prompt"
        echo "    $runtime_cmd              Launch agent session"
      elif [[ "$m_status" == "completed" ]]; then
        echo -e "  ${C_DIM}Mission completed. Start a new one with: mosaic coord init${C_RESET}"
      else
        echo -e "  ${C_DIM}Initialize with: mosaic coord init --name \"Mission Name\"${C_RESET}"
      fi
      echo ""
    fi
  else
    if [[ "$FORMAT" == "json" ]]; then
      echo '{"status":"no-session","mission":null}'
    else
      echo ""
      echo -e "  ${C_DIM}No active session.${C_RESET}"
      echo -e "  ${C_DIM}No mission found.${C_RESET}"
      echo ""
      echo "  Initialize with: mosaic coord init --name \"Mission Name\""
      echo ""
    fi
  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"