#!/usr/bin/env bash
# pi_wake_agent.sh — Reusable multi-agent wake-up timer with self-cron/daemon
set -euo pipefail

# ─── Constants ────────────────────────────────────────────────────────────
SCRIPT_PATH="$(readlink -f "${BASH_SOURCE[0]}")"
LOG_FILE="/tmp/pi_wake_agent.log"
LOG_MAX_SIZE=$((10 * 1024 * 1024))
LOG_MAX_FILES=5
CRON_COMMENT_PREFIX="pi_wake_agent"
AGENT_NICK="pi_nvnemo"
H5I_AGENT="pi_nvnemo"
H5I_BUS_ROOT="/mnt/dolphinng5_predict"
DEFAULT_INTERVAL="1h"
PANE=""
CRON_PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
PYTHON_BIN="/usr/bin/python3"

# ─── Logging ──────────────────────────────────────────────────────────────
log_rotate() {
    [[ -f "$LOG_FILE" ]] || return 0
    local size
    size=$(stat -c%s "$LOG_FILE" 2>/dev/null || echo 0)
    [[ $size -lt $LOG_MAX_SIZE ]] && return 0
    for i in $(seq $((LOG_MAX_FILES - 1)) -1 1); do
        [[ -f "${LOG_FILE}.${i}" ]] && mv "${LOG_FILE}.${i}" "${LOG_FILE}.$((i + 1))"
    done
    mv "$LOG_FILE" "${LOG_FILE}.1"
}

log_write() {
    local level="$1"; shift
    local msg="$*"
    local ts
    ts=$(date '+%Y-%m-%d %H:%M:%S')
    log_rotate
    echo "[$ts] [$level] $msg" >> "$LOG_FILE"
    if [[ "$level" == "ERROR" || "$level" == "WARN" ]]; then
        echo "[$ts] [$level] $msg" >&2
    fi
    return 0
}

log_debug() { [[ ${DEBUG:-0} == "1" ]] && log_write "DEBUG" "$@"; }
log_info()  { log_write "INFO" "$@"; }
log_warn()  { log_write "WARN" "$@"; }
log_error() { log_write "ERROR" "$@"; }

# ─── Interval Parsing ────────────────────────────────────────────────────
parse_interval() {
    local interval="$1"
    local seconds=0
    if [[ "$interval" =~ ^([0-9]+)h$ ]]; then
        seconds=$((BASH_REMATCH[1] * 3600))
    elif [[ "$interval" =~ ^([0-9]+)m$ ]]; then
        seconds=$((BASH_REMATCH[1] * 60))
    elif [[ "$interval" =~ ^([0-9]+)s$ ]]; then
        seconds=$((BASH_REMATCH[1]))
    else
        log_error "Invalid interval format '$interval'. Use like 1h, 30m, 90m, 2h"
        return 1
    fi
    echo "$seconds"
    return 0
}

interval_to_cron() {
    local interval="$1"
    if [[ "$interval" =~ ^([0-9]+)h$ ]]; then
        local hours="${BASH_REMATCH[1]}"
        echo "0 */${hours} * * *"
    elif [[ "$interval" =~ ^([0-9]+)m$ ]]; then
        local mins="${BASH_REMATCH[1]}"
        if (( mins >= 60 )); then
            log_error "For minutes >= 60, use hours (e.g., 1h not 60m)"
            return 1
        fi
        echo "*/${mins} * * * *"
    else
        log_error "Cron only supports minutes/hours intervals"
        return 1
    fi
}

interval_to_human() {
    local interval="$1"
    if [[ "$interval" =~ ^([0-9]+)h$ ]]; then
        echo "${BASH_REMATCH[1]} hour(s)"
    elif [[ "$interval" =~ ^([0-9]+)m$ ]]; then
        echo "${BASH_REMATCH[1]} minute(s)"
    elif [[ "$interval" =~ ^([0-9]+)s$ ]]; then
        echo "${BASH_REMATCH[1]} second(s)"
    else
        echo "$interval"
    fi
}

# ─── Session Parsing ─────────────────────────────────────────────────────
parse_sessions() {
    local raw="${1:-}"
    [[ -z "$raw" ]] && return 0
    IFS=',' read -ra SESSIONS <<< "$raw"
    for i in "${!SESSIONS[@]}"; do
        SESSIONS[i]=$(echo "${SESSIONS[i]}" | xargs)
    done
}

# ─── Cron Management ────────────────────────────────────────────────────
cron_comment() {
    local sessions_str
    sessions_str=$(IFS=,; echo "${SESSIONS[*]}")
    echo "${CRON_COMMENT_PREFIX}:${sessions_str}:${INTERVAL}"
}

install_cron() {
    local cron_sched
    cron_sched=$(interval_to_cron "$INTERVAL") || return 1
    local comment
    comment=$(cron_comment)
    local pane_arg=""
    [[ -n "$PANE" ]] && pane_arg="--pane ${PANE}"
    local cmd="cd ${H5I_BUS_ROOT} && export PATH=${CRON_PATH} && export H5I_AGENT=${H5I_AGENT} && ${PYTHON_BIN} ${SCRIPT_PATH} --run --sessions \"${SESSIONS[*]}\" --msg \"${MESSAGE}\" ${pane_arg}"

    (crontab -l 2>/dev/null | grep -v "${comment}") | crontab -
    (crontab -l 2>/dev/null; echo "${cron_sched} ${cmd} # ${comment}") | crontab -
    
    log_info "Installed cron: ${cron_sched} -> ${SESSIONS[*]} every ${INTERVAL}"
}

remove_cron() {
    local comment
    comment=$(cron_comment)
    (crontab -l 2>/dev/null | grep -v "${comment}") | crontab -
    log_info "Removed cron for ${SESSIONS[*]} (${INTERVAL})"
}

list_cron() {
    echo "=== pi_wake_agent cron entries ==="
    crontab -l 2>/dev/null | grep "${CRON_COMMENT_PREFIX}" || echo "None found"
}

# ─── Zellij Operations ──────────────────────────────────────────────────
zellij_session_exists() {
    local session="$1"
    zellij list-sessions 2>/dev/null | grep -q "^${session} "
}

zellij_write_chars() {
    local session="$1"
    local text="$2"
    zellij --session "$session" action write-chars ${PANE:+--pane-id "$PANE"} "$text" 2>/dev/null || true
}

zellij_write_enter() {
    local session="$1"
    zellij --session "$session" action write ${PANE:+--pane-id "$PANE"} 13 2>/dev/null || true
}

# ─── Wake Action ────────────────────────────────────────────────────────
run_wake() {
    local sessions_str
    sessions_str=$(IFS=,; echo "${SESSIONS[*]}")
    log_info "Waking ${sessions_str} with message: ${MESSAGE}"
    
    for session in "${SESSIONS[@]}"; do
        zellij_write_chars "$session" "[${AGENT_NICK} via zellij] ${MESSAGE} Run: h5i-bus msg inbox"
        for i in 1 2 3 4 5; do
            zellij_write_enter "$session"
            sleep 1
        done
    done
    
    cd "${H5I_BUS_ROOT}" && export H5I_AGENT="${H5I_AGENT}" && h5i msg send Fable "${MESSAGE} (timer wakeup)" 2>/dev/null || true
    
    log_info "Wake sent to ${sessions_str}"
}

# ─── Modes ──────────────────────────────────────────────────────────────
run_once() {
    local interval_seconds
    interval_seconds=$(parse_interval "$INTERVAL") || return 1
    
    log_info "One-shot timer set for ${INTERVAL} ($(interval_to_human "$INTERVAL"))"
    
    (
        sleep "$interval_seconds"
        run_wake
    ) &
    
    local pid=$!
    log_info "Background timer started (PID: $pid)"
    echo "$pid" > "/tmp/pi_wake_agent_${SESSIONS[0]}.pid"
    return 0
}

run_daemon() {
    local interval_seconds
    interval_seconds=$(parse_interval "$INTERVAL") || return 1
    
    log_info "=== DAEMON START ==="
    log_info "Interval: ${INTERVAL} ($(interval_to_human "$INTERVAL"))"
    log_info "Sessions: ${SESSIONS[*]}"
    log_info "Message: ${MESSAGE}"
    
    run_wake
    
    while true; do
        log_debug "Sleeping for ${interval_seconds}s..."
        sleep "$interval_seconds"
        run_wake
    done
}

status() {
    echo "=== pi_wake_agent Status ==="
    echo "Script: ${SCRIPT_PATH}"
    echo "Log: ${LOG_FILE}"
    echo "Log size: $(du -h "$LOG_FILE" 2>/dev/null | cut -f1 || echo 'N/A')"
    echo "Agent: ${AGENT_NICK}"
    echo ""
    list_cron
    echo ""
    echo "=== Active one-shot timers ==="
    local found=0
    for pidfile in /tmp/pi_wake_agent_*.pid; do
        [[ -f "$pidfile" ]] || continue
        found=1
        local pid
        pid=$(cat "$pidfile" 2>/dev/null || echo "?")
        if kill -0 "$pid" 2>/dev/null; then
            echo "  PID $pid (active)"
        else
            echo "  PID $pid (dead, cleaning up)"
            rm -f "$pidfile"
        fi
    done
    [[ $found -eq 0 ]] && echo "  (none)"
}

validate_sessions() {
    log_info "Validating sessions: ${SESSIONS[*]}"
    for session in "${SESSIONS[@]}"; do
        if zellij_session_exists "$session"; then
            log_info "  $session: EXISTS"
        else
            log_warn "  $session: NOT FOUND (may be dead/EXITED)"
        fi
    done
}

# ─── Usage ──────────────────────────────────────────────────────────────
usage() {
    cat <<USAGE
pi_wake_agent.sh — Reusable multi-agent wake-up timer with self-cron/daemon

USAGE:
  pi_wake_agent.sh --install [OPTIONS]    Install recurring cron timer
  pi_wake_agent.sh --once [OPTIONS]       One-shot wake (no cron)
  pi_wake_agent.sh --daemon [OPTIONS]     Run as long-lived daemon (no cron)
  pi_wake_agent.sh --run [OPTIONS]        Internal: run wake action (called by cron)
  pi_wake_agent.sh --remove [OPTIONS]     Remove cron timer
  pi_wake_agent.sh --list                 List active cron timers
  pi_wake_agent.sh --status               Show status (cron + one-shot timers)
  pi_wake_agent.sh --validate [OPTIONS]   Validate sessions exist in zellij

OPTIONS:
  --interval DURATION    Interval (default: 1h). Formats: 30m, 1h, 90m, 2h, etc.
  --session SESSION      Zellij session name (can repeat or comma-separate)
  --sessions "A,B,C"     Comma-separated list of sessions
  --msg "MESSAGE"        Wake message (default: "Operator says CONTINUE. Pi here!")
  --pane PANE            Zjet pane ID to target (focused pane if unset), e.g. terminal_1
  --debug                Enable debug logging
  --help                 Show this help

EXAMPLES:
  # Install recurring 1-hour timer for one session
  pi_wake_agent.sh --install --interval 1h --session cc_UV_dev0_Fb

  # Install 30-minute timer for multiple sessions
  pi_wake_agent.sh --install --interval 30m --sessions "cc_UV_dev0_Fb,cc_UV_dev1_48" --msg "Wake up!"

  # One-shot wake in 2 hours (no cron)
  pi_wake_agent.sh --once --interval 2h --session cc_UV_dev0_Fb --msg "Time's up!"

  # Run as daemon (long-lived process, no cron)
  pi_wake_agent.sh --daemon --interval 1h --session cc_UV_dev0_Fb

  # Remove timer
  pi_wake_agent.sh --remove --session cc_UV_dev0_Fb --interval 1h

  # List all timers
  pi_wake_agent.sh --list

  # Show status
  pi_wake_agent.sh --status

  # Validate sessions
  pi_wake_agent.sh --validate --session cc_UV_dev0_Fb

NOTES:
  - Identifies as ${AGENT_NICK} on h5i bus
  - Sends 5× ENTER keypresses (1s delay) for reliable submission
  - Self-cron: installs/removes own cron entries
  - Structured logging to ${LOG_FILE} (rotated at 10MB, 5 files)
  - Daemon mode runs indefinitely until killed (SIGTERM/SIGINT handled)
  - Cron comments format: ${CRON_COMMENT_PREFIX}:<sessions>:<interval>
USAGE
}

# ─── Main ───────────────────────────────────────────────────────────────
MODE="install"
INTERVAL="${DEFAULT_INTERVAL}"
SESSIONS=()
MESSAGE="Operator says CONTINUE. ${AGENT_NICK} here, saying hi!"
SESSIONS_RAW=""
DEBUG="${DEBUG:-0}"

# Parse arguments
while [[ $# -gt 0 ]]; do
    case "$1" in
        --install) MODE="install"; shift ;;
        --once) MODE="once"; shift ;;
        --daemon) MODE="daemon"; shift ;;
        --run) MODE="run"; shift ;;
        --remove) MODE="remove"; shift ;;
        --list) MODE="list"; shift ;;
        --status) MODE="status"; shift ;;
        --validate) MODE="validate"; shift ;;
        --interval) INTERVAL="$2"; shift 2 ;;
        --session) SESSIONS_RAW="${SESSIONS_RAW:+${SESSIONS_RAW},}$2"; shift 2 ;;
        --sessions) SESSIONS_RAW="$2"; shift 2 ;;
        --msg) MESSAGE="$2"; shift 2 ;;
        --pane) PANE="$2"; shift 2 ;;
        --debug) DEBUG=1; shift ;;
        --help) usage; exit 0 ;;
        *) log_error "Unknown option: $1"; usage; exit 1 ;;
    esac
done

# Parse sessions
parse_sessions "${SESSIONS_RAW}"

# Validate
if [[ ${#SESSIONS[@]} -eq 0 && "$MODE" != "list" && "$MODE" != "status" ]]; then
    log_error "--session or --sessions required"
    usage
    exit 1
fi

# Log startup
log_info "=== pi_wake_agent ${MODE} ==="
log_info "Interval: ${INTERVAL} ($(interval_to_human "$INTERVAL"))"
log_info "Sessions: ${SESSIONS[*]}"
[[ -n "$PANE" ]] && log_info "Pane target: ${PANE}"
[[ -n "$MESSAGE" ]] && log_info "Message: ${MESSAGE}"

# Execute mode
case "$MODE" in
    install) install_cron ;;
    once) run_once ;;
    daemon) run_daemon ;;
    run) run_wake ;;
    remove) remove_cron ;;
    list) list_cron ;;
    status) status ;;
    validate) validate_sessions ;;
    *) log_error "Unknown mode: $MODE"; usage; exit 1 ;;
esac