#!/usr/bin/env bash
# Preflight: RPC reachability and eth_chainId for XDC Zero second pair (parent ↔ Chain 138).
# Optional: ETHEREUM_MAINNET_RPC (or other vars) for quick public mainnet access checks.
#
# Usage:
#   bash scripts/verify/xdc-zero-chain138-preflight.sh
#   XDC mainnet: set XDC_PARENTNET_URL or rely on fallbacks (erpc.xinfin.network, Ankr, rpc.xinfin.network).
#   Apothem: XDC_PARENTNET_URL=https://rpc.apothem.network bash scripts/verify/xdc-zero-chain138-preflight.sh
#
# Loads repo dotenv via scripts/lib/load-project-env.sh when sourced from repo root.

# Avoid nounset while sourcing dotenv (some .env lines reference optional vars).
set -eo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
# shellcheck source=/dev/null
source "${PROJECT_ROOT}/scripts/lib/load-project-env.sh"

_rpc_chain_id() {
  local url="$1"
  local name="$2"
  if [[ -z "$url" || "$url" == "devnet" || "$url" == "testnet" ]]; then
    echo "SKIP $name: empty or alias URL ($url) — resolve to HTTPS RPC for this check."
    return 0
  fi
  local out
  if ! out="$(curl -sS --connect-timeout 8 --max-time 20 -X POST "$url" \
    -H 'Content-Type: application/json' \
    -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}' 2>/dev/null)"; then
    echo "FAIL $name: no HTTP response from $url"
    return 1
  fi
  local hex
  hex="$(printf '%s' "$out" | sed -n 's/.*"result":"\([^"]*\)".*/\1/p')"
  if [[ -z "$hex" ]]; then
    echo "FAIL $name: bad JSON or error from $url — $out"
    return 1
  fi
  echo "OK   $name ($url) eth_chainId=$hex"
}

_balance_eth() {
  local url="$1"
  local addr="$2"
  local out
  if ! out="$(curl -sS --connect-timeout 8 --max-time 20 -X POST "$url" \
    -H 'Content-Type: application/json' \
    -d "{\"jsonrpc\":\"2.0\",\"method\":\"eth_getBalance\",\"params\":[\"${addr}\",\"latest\"],\"id\":1}" 2>/dev/null)"; then
    echo ""
    return 1
  fi
  local hex
  hex="$(printf '%s' "$out" | sed -n 's/.*"result":"\([^"]*\)".*/\1/p')"
  [[ -n "$hex" ]] || return 1
  cast to-unit "$hex" ether 2>/dev/null || printf '%s' "$hex"
}

# Echo chainId hex or empty if URL is not a working JSON-RPC endpoint.
_eth_chain_id_hex() {
  local url="$1"
  local out hex
  if ! out="$(curl -sS --connect-timeout 8 --max-time 20 -X POST "$url" \
    -H 'Content-Type: application/json' \
    -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}' 2>/dev/null)"; then
    return 1
  fi
  hex="$(printf '%s' "$out" | sed -n 's/.*"result":"\([^"]*\)".*/\1/p')"
  [[ -n "$hex" ]] || return 1
  printf '%s' "$hex"
}

# Pick first working XDC parent RPC; sets global PARENT to the URL that answered.
_resolve_xdc_parent_rpc() {
  local primary="${XDC_PARENTNET_URL:-}"
  [[ -z "$primary" ]] && primary="${PARENTNET_URL:-}"
  local fallbacks=(
    "https://erpc.xinfin.network"
    "https://rpc.ankr.com/xdc"
    "https://rpc.xinfin.network"
  )
  local candidates=()
  [[ -n "$primary" ]] && candidates+=("$primary")
  candidates+=("${fallbacks[@]}")
  local seen="|" u hex
  for u in "${candidates[@]}"; do
    [[ -z "$u" || "$u" == "devnet" || "$u" == "testnet" ]] && continue
    case "$seen" in *"|$u|"*) continue;; esac
    seen="${seen}${u}|"
    if hex="$(_eth_chain_id_hex "$u")"; then
      echo "OK   XDC parent ($u) eth_chainId=$hex"
      PARENT="$u"
      return 0
    fi
  done
  echo "FAIL XDC parent: no working RPC (tried ${#candidates[@]} candidate URLs; set XDC_PARENTNET_URL to a healthy endpoint)"
  return 1
}

echo "=== XDC Zero Chain 138 pair — RPC preflight ==="

fail=0
PARENT=""
if [[ -n "${XDC_PARENTNET_URL:-${PARENTNET_URL:-}}" ]]; then
  echo "INFO XDC parent: trying XDC_PARENTNET_URL / PARENTNET_URL first, then public fallbacks if needed"
else
  echo "INFO XDC_PARENTNET_URL and PARENTNET_URL unset — trying public XDC mainnet RPC fallbacks"
fi
_resolve_xdc_parent_rpc || fail=1

PEER_OPERATOR="${XDC_ZERO_PEER_RPC_URL:-${RPC_URL_138:-${CHAIN138_RPC_URL:-${CHAIN138_RPC:-}}}}"
PEER_SERVICE="${CHAIN138_PUBLIC_RPC_URL:-${SUBNET_URL:-${RPC_URL_138_PUBLIC:-}}}"

if [[ -n "$PEER_OPERATOR" ]]; then
  _rpc_chain_id "$PEER_OPERATOR" "Chain138 operator RPC_URL_138" || fail=1
else
  echo "WARN RPC_URL_138 (or CHAIN138_RPC_URL) unset — set for Chain 138 checks."
fi

if [[ -n "$PEER_SERVICE" ]]; then
  _rpc_chain_id "$PEER_SERVICE" "Chain138 service CHAIN138_PUBLIC_RPC_URL / SUBNET_URL / RPC_URL_138_PUBLIC" || fail=1
else
  echo "WARN CHAIN138_PUBLIC_RPC_URL, SUBNET_URL, and RPC_URL_138_PUBLIC unset — set one for relayer/service checks."
fi

if [[ -n "${ETHEREUM_MAINNET_RPC:-}" ]]; then
  _rpc_chain_id "$ETHEREUM_MAINNET_RPC" "ETHEREUM_MAINNET_RPC (optional)" || fail=1
fi

if [[ -n "${BSC_RPC_URL:-}" ]]; then
  _rpc_chain_id "$BSC_RPC_URL" "BSC_RPC_URL (optional)" || fail=1
fi

if [[ "$fail" -ne 0 ]]; then
  echo "=== Preflight finished with failures ==="
  exit 1
fi

if [[ -n "${PRIVATE_KEY:-}" ]]; then
  DEPLOYER_ADDR="$(cast wallet address --private-key "$PRIVATE_KEY" 2>/dev/null || true)"
  if [[ -n "$DEPLOYER_ADDR" ]]; then
    echo ""
    echo "Deployer readiness"
    echo "  deployer_address: $DEPLOYER_ADDR"
    if [[ -n "$PARENT" ]]; then
      parent_bal="$(_balance_eth "$PARENT" "$DEPLOYER_ADDR" || true)"
      if [[ -n "$parent_bal" ]]; then
        echo "  parent_balance:   $parent_bal"
        if [[ "$parent_bal" == "0.000000000000000000" || "$parent_bal" == "0" || "$parent_bal" == "0x0" ]]; then
          echo "  note:             deployer has no native gas on parent; parent Endpoint/CSC deploy and registerChain are blocked until funded."
        fi
      fi
    fi
    if [[ -n "$PEER_OPERATOR" ]]; then
      peer_bal="$(_balance_eth "$PEER_OPERATOR" "$DEPLOYER_ADDR" || true)"
      [[ -n "$peer_bal" ]] && echo "  chain138_balance: $peer_bal"
    fi
  fi
fi

echo "=== Preflight finished ==="
echo "Next: deploy Endpoint/CSC per docs/03-deployment/CHAIN138_XDC_ZERO_BRIDGE_RUNBOOK.md"