#!/usr/bin/env bash
set -u

DURATION_SECONDS="${DURATION_SECONDS:-900}"
INTERVAL_SECONDS="${INTERVAL_SECONDS:-5}"
CONNECT_TIMEOUT_SECONDS="${CONNECT_TIMEOUT_SECONDS:-3}"
TCP_PROBE_PYTHON="${TCP_PROBE_PYTHON:-python3}"
RUN_ID="${RUN_ID:-$(date -u '+%Y%m%dT%H%M%SZ')}"
ARTIFACT_DIR="${ARTIFACT_DIR:-/tmp/awoooi-full-host-reboot-drill/${RUN_ID}}"

HOST_SPECS=(
  "99|192.168.0.99|22"
  "110|192.168.0.110|22"
  "111|192.168.0.111|22"
  "112|192.168.0.112|22"
  "120|192.168.0.120|22"
  "121|192.168.0.121|22"
  "188|192.168.0.188|22"
)
ROUTE_SPECS=(
  "awoooi-api|https://awoooi.wooo.work/api/v1/health"
  "awoooi-web|https://awoooi.wooo.work/"
  "stock|https://stock.wooo.work/api/v1/system/freshness"
  "momo|https://mo.wooo.work/health"
  "gitea|https://gitea.wooo.work/"
  "harbor|https://harbor.wooo.work/"
)

usage() {
  printf '%s\n' "usage: $0 [--duration SECONDS] [--interval SECONDS] [--artifact-dir DIR]"
}

is_positive_integer() {
  [[ "$1" =~ ^[1-9][0-9]*$ ]]
}

while [[ $# -gt 0 ]]; do
  case "$1" in
    --duration)
      shift
      DURATION_SECONDS="${1:-}"
      ;;
    --interval)
      shift
      INTERVAL_SECONDS="${1:-}"
      ;;
    --artifact-dir)
      shift
      ARTIFACT_DIR="${1:-}"
      ;;
    --help|-h)
      usage
      exit 0
      ;;
    *)
      printf 'error=unknown_argument:%s\n' "$1" >&2
      usage >&2
      exit 64
      ;;
  esac
  shift
done

if ! is_positive_integer "$DURATION_SECONDS" || ! is_positive_integer "$INTERVAL_SECONDS"; then
  printf '%s\n' "error=duration_and_interval_must_be_positive_integers" >&2
  exit 64
fi

if ! command -v "$TCP_PROBE_PYTHON" >/dev/null 2>&1; then
  printf 'error=tcp_probe_python_not_found:%s\n' "$TCP_PROBE_PYTHON" >&2
  exit 69
fi

mkdir -p "$ARTIFACT_DIR/state"
SAMPLES_TSV="$ARTIFACT_DIR/samples.tsv"
EVENTS_TSV="$ARTIFACT_DIR/events.tsv"
SUMMARY_TXT="$ARTIFACT_DIR/summary.txt"
printf 'observed_at\tkind\ttarget\tstate\tdetail\n' >"$SAMPLES_TSV"
printf 'observed_at\tkind\ttarget\tprevious_state\tstate\tdetail\n' >"$EVENTS_TSV"

sanitize_name() {
  printf '%s' "$1" | tr -c 'A-Za-z0-9._-' '_'
}

probe_host() {
  local observed_at="$1" alias="$2" address="$3" port="$4" output="$5"
  if "$TCP_PROBE_PYTHON" - "$address" "$port" "$CONNECT_TIMEOUT_SECONDS" >/dev/null 2>&1 <<'PY'; then
import socket
import sys

address = sys.argv[1]
port = int(sys.argv[2])
timeout_seconds = float(sys.argv[3])
with socket.create_connection((address, port), timeout=timeout_seconds):
    pass
PY
    printf '%s\thost\t%s\tup\ttcp_%s_open\n' "$observed_at" "$alias" "$port" >"$output"
  else
    printf '%s\thost\t%s\tdown\ttcp_%s_closed_or_unreachable\n' "$observed_at" "$alias" "$port" >"$output"
  fi
}

probe_route() {
  local observed_at="$1" name="$2" url="$3" output="$4"
  local code="000"
  code="$(curl --silent --show-error --location --max-time "$CONNECT_TIMEOUT_SECONDS" --output /dev/null --write-out '%{http_code}' "$url" 2>/dev/null || true)"
  case "$code" in
    2??|3??|401)
      printf '%s\troute\t%s\tup\thttp_%s\n' "$observed_at" "$name" "$code" >"$output"
      ;;
    *)
      printf '%s\troute\t%s\tdown\thttp_%s\n' "$observed_at" "$name" "${code:-000}" >"$output"
      ;;
  esac
}

record_transition() {
  local observed_at="$1" kind="$2" target="$3" state="$4" detail="$5"
  local state_file="$ARTIFACT_DIR/state/$(sanitize_name "${kind}-${target}").state"
  local previous="unknown"
  if [[ -f "$state_file" ]]; then
    previous="$(<"$state_file")"
  fi
  if [[ "$state" != "$previous" ]]; then
    printf '%s\t%s\t%s\t%s\t%s\t%s\n' "$observed_at" "$kind" "$target" "$previous" "$state" "$detail" >>"$EVENTS_TSV"
    printf '%s' "$state" >"$state_file"
  fi
}

START_EPOCH="$(date +%s)"
DEADLINE_EPOCH="$((START_EPOCH + DURATION_SECONDS))"

while [[ "$(date +%s)" -lt "$DEADLINE_EPOCH" ]]; do
  observed_at="$(date -u '+%Y-%m-%dT%H:%M:%SZ')"
  sample_dir="$ARTIFACT_DIR/sample-$(date +%s)-$$"
  mkdir -p "$sample_dir"

  for spec in "${HOST_SPECS[@]}"; do
    IFS='|' read -r alias address port <<<"$spec"
    probe_host "$observed_at" "$alias" "$address" "$port" "$sample_dir/host-$alias.tsv" &
  done
  for spec in "${ROUTE_SPECS[@]}"; do
    IFS='|' read -r name url <<<"$spec"
    probe_route "$observed_at" "$name" "$url" "$sample_dir/route-$name.tsv" &
  done
  wait

  for sample in "$sample_dir"/*.tsv; do
    IFS=$'\t' read -r timestamp kind target state detail <"$sample"
    printf '%s\t%s\t%s\t%s\t%s\n' "$timestamp" "$kind" "$target" "$state" "$detail" >>"$SAMPLES_TSV"
    record_transition "$timestamp" "$kind" "$target" "$state" "$detail"
  done
  rm -rf "$sample_dir"
  sleep "$INTERVAL_SECONDS"
done

host_down_samples="$(awk -F '\t' '$2=="host" && $4=="down" {count++} END {print count+0}' "$SAMPLES_TSV")"
route_down_samples="$(awk -F '\t' '$2=="route" && $4=="down" {count++} END {print count+0}' "$SAMPLES_TSV")"
down_transitions="$(awk -F '\t' '$5=="down" {count++} END {print count+0}' "$EVENTS_TSV")"
recovery_transitions="$(awk -F '\t' '$4=="down" && $5=="up" {count++} END {print count+0}' "$EVENTS_TSV")"
first_down_at="$(awk -F '\t' '$5=="down" {print $1; exit}' "$EVENTS_TSV")"
last_recovered_at="$(awk -F '\t' '$4=="down" && $5=="up" {value=$1} END {print value}' "$EVENTS_TSV")"

{
  printf 'schema_version=full_host_reboot_drill_observer_v1\n'
  printf 'run_id=%s\n' "$RUN_ID"
  printf 'duration_seconds=%s\n' "$DURATION_SECONDS"
  printf 'interval_seconds=%s\n' "$INTERVAL_SECONDS"
  printf 'host_count=%s\n' "${#HOST_SPECS[@]}"
  printf 'route_count=%s\n' "${#ROUTE_SPECS[@]}"
  printf 'host_down_samples=%s\n' "$host_down_samples"
  printf 'route_down_samples=%s\n' "$route_down_samples"
  printf 'down_transitions=%s\n' "$down_transitions"
  printf 'recovery_transitions=%s\n' "$recovery_transitions"
  printf 'first_down_at=%s\n' "${first_down_at:-none}"
  printf 'last_recovered_at=%s\n' "${last_recovered_at:-none}"
  printf 'samples=%s\n' "$SAMPLES_TSV"
  printf 'events=%s\n' "$EVENTS_TSV"
  printf 'secret_value_read=false\n'
  printf 'remote_write_performed=false\n'
  printf 'reboot_command_executed=false\n'
} >"$SUMMARY_TXT"

cat "$SUMMARY_TXT"