#!/usr/bin/env bash
set -euo pipefail

# Usage: ./gen-client-from-url.sh "vless://uuid@host:443?type=tcp&security=reality&pbk=PUBLIC_KEY&fp=random&sni=yahoo.com&sid=SHORTID&spx=%2F&flow=xtls-rprx-vision#tag" [output.json]
# If output not set, defaults to client.json

URL_INPUT=${1:-}
OUT_FILE=${2:-client.json}
TEMPLATE_DIR="$(cd "$(dirname "$0")" && pwd)"
TEMPLATE_FILE="$TEMPLATE_DIR/client.template.json"

if [[ -z "$URL_INPUT" ]]; then
  echo "Error: provide VLESS reality URL or Subscription URL" >&2
  exit 1
fi

if [[ ! -f "$TEMPLATE_FILE" ]]; then
  echo "Template not found: $TEMPLATE_FILE" >&2
  exit 1
fi

# Detect if input is a subscription link (HTTP/HTTPS)
if [[ "$URL_INPUT" =~ ^http ]]; then
  echo "Detecting subscription link..."
  
  # Build URL with client parameter for APIs that require it
  SUB_URL="$URL_INPUT"
  
  # Try fetching as-is first
  SUB_CONTENT=$(curl -sSL "$SUB_URL")
  
  # If empty, try adding client parameter (some APIs require this)
  if [[ -z "$SUB_CONTENT" ]]; then
    echo "Empty response, trying with client=v2rayng parameter..."
    if [[ "$SUB_URL" == *"?"* ]]; then
      SUB_URL="${URL_INPUT}&client=v2rayng"
    else
      SUB_URL="${URL_INPUT}?client=v2rayng"
    fi
    SUB_CONTENT=$(curl -sSL "$SUB_URL")
  fi
  
  if [[ -z "$SUB_CONTENT" ]]; then
    echo "Error: Failed to download subscription from $SUB_URL" >&2
    exit 1
  fi

  # Check if base64 encoded (simple check: no spaces, looks like b64)
  # Trying to decode. If fails, assume it's plain text lists
  if DECODED=$(echo "$SUB_CONTENT" | base64 -d 2>/dev/null); then
     echo "Decoded base64 subscription."
     RAW_CONFIGS="$DECODED"
  else
     echo "Using plain text subscription."
     RAW_CONFIGS="$SUB_CONTENT"
  fi

  # Find first vless reality link (vless://... + security=reality or just vless://)
  # We try to find one that explicitly has reality, if not, pick ANY vless
  TARGET_URL=$(echo "$RAW_CONFIGS" | grep -o 'vless://[^[:space:]]*' | grep 'security=reality' | head -n 1)

  if [[ -z "$TARGET_URL" ]]; then
    echo "No VLESS Reality link found, trying any VLESS..."
    TARGET_URL=$(echo "$RAW_CONFIGS" | grep -o 'vless://[^[:space:]]*' | head -n 1)
  fi

  if [[ -z "$TARGET_URL" ]]; then
     echo "Error: No VLESS URL found in subscription." >&2
     exit 1
  fi

  echo "Selected URL from subscription: ${TARGET_URL:0:30}..."
  URL_INPUT="$TARGET_URL"
fi

# Strip scheme
URL_NOSCHEME=${URL_INPUT#vless://}

UUID_HOST_PORT=${URL_NOSCHEME%%\?*}
QUERY_AND_TAG=${URL_NOSCHEME#*?}
QUERY=${QUERY_AND_TAG%%#*}
TAG_RAW=${URL_INPUT#*#}
TAG=${TAG_RAW:-reality}

UUID=${UUID_HOST_PORT%%@*}
HOST_PORT=${UUID_HOST_PORT#*@}
HOST=${HOST_PORT%%:*}
PORT=${HOST_PORT##*:}

# Parse query params (portable, no associative arrays)
PBK=""; FINGERPRINT="chrome"; SNI=""; SHORT_ID=""; SPX=""; FLOW=""
OLD_IFS=$IFS
IFS='&'
set +u
for kv in $QUERY; do
  key=${kv%%=*}
  val=${kv#*=}
  case "$key" in
    pbk) PBK=$val ;;
    fp) FINGERPRINT=$val ;;
    sni) SNI=$val ;;
    sid) SHORT_ID=$val ;;
    spx) SPX=$val ;;
    flow) FLOW=$val ;;
  esac
done
set -u
IFS=$OLD_IFS
SNI=${SNI:-$HOST}
# SPX currently not used

if [[ -z "$UUID" || -z "$HOST" || -z "$PORT" || -z "$PBK" || -z "$SHORT_ID" ]]; then
  echo "Missing required fields (uuid/host/port/pbk/sid)" >&2
  exit 1
fi

TMP=$(mktemp)
cp "$TEMPLATE_FILE" "$TMP"

# Perform replacements safely using jq
# Replace simple placeholders
jq \
  --arg uuid "$UUID" \
  --arg server "$HOST" \
  --argjson port "$PORT" \
  --arg tag "$TAG" \
  --arg sni "$SNI" \
  --arg fp "$FINGERPRINT" \
  --arg pk "$PBK" \
  --arg sid "$SHORT_ID" \
  --arg flow "$FLOW" '
  (.outbounds[] | select(.type=="vless")) as $v | (
    .outbounds |= map(if .type=="vless" then (
      .uuid=$uuid
      | .server=$server
      | .server_port=$port
      | .tag=$tag
      | .tls.server_name=$sni
      | .tls.utls.fingerprint=$fp
      | .tls.reality.public_key=$pk
      | .tls.reality.short_id=$sid
      | .flow=$flow
    ) else . end)
    | .route.final=$tag
  )' "$TMP" > "$OUT_FILE"

rm "$TMP"

echo "Generated $OUT_FILE from URL (tag=$TAG)"