wedb_standalone 0.1.1

//! 解析态扩展选项解析族（对标 libs/server/SessionParseStateExtensions.cs:SessionParseStateExtensions）
//!
//! C# 以扩展方法挂在 `SessionParseState` 上；Rust 侧以
//! [`SessionParseStateExtensions`] 关联函数承接同一 API 面。枚举 / 数值解析
//! 语义与错误文案逐项对齐 C#（大小写不敏感匹配 + 严格数值解析）。
//!
//! 注：C# `RespCommand` 参数在此以 `&str` 命令名承接（GEOSEARCH 族判定仅比
//! 较命令名；rust resp 命令域的 RespCommand 元数据表由并行域落地）。

use std::str::from_utf8;

use wobject::list::list_object::OperationDirection;

use crate::{
  metrics::{
    info_metrics_type::InfoMetricsType, latency::latency_metrics_type::LatencyMetricsType,
  },
  resp::{
    cmd_strings,
    parser::session_parse_state::{strict_f64, strict_i32, strict_i64},
  },
  session_parse_state::SessionParseState,
  storage::session::objectstore::sorted_set_ops::ZSetAggregate,
};

/// CLIENT 子命令的客户端类型（Garnet.common:ClientType 语义；Invalid 为哨兵）
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ClientType {
  /// 非法（解析失败哨兵，对齐 C# ClientType.Invalid）
  Invalid,
  /// 普通连接
  Normal,
  /// 主节点
  Master,
  /// 副本
  Replica,
  /// 订阅连接
  Pubsub,
  /// 副本（旧称）
  Slave,
}

/// BITFIELD OVERFLOW 行为（Garnet.common:BitFieldOverflow）
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum BitFieldOverflow {
  /// 回绕
  Wrap,
  /// 饱和
  Sat,
  /// 失败（回吐 nil）
  Fail,
}

/// GEOSEARCH 原点种类（Garnet.common:GeoOriginType）
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum GeoOriginType {
  /// 未设置（哨兵 0）
  #[default]
  Undefined,
  /// 以成员为原点
  FromMember,
  /// 以经纬度为原点
  FromLonLat,
}

/// GEOSEARCH 形状种类（Garnet.common:GeoSearchType）
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum GeoSearchType {
  /// 未设置（哨兵 0）
  #[default]
  Undefined,
  /// 圆形（半径）
  ByRadius,
  /// 矩形（宽高）
  ByBox,
}

/// GEOSEARCH 排序方向（Garnet.common:GeoOrder）
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum GeoOrder {
  /// 不排序（默认）
  #[default]
  None,
  /// 由近及远
  Ascending,
  /// 由远及近
  Descending,
}

/// GEO 距离单位（Garnet.common:GeoDistanceUnitType）
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum GeoDistanceUnitType {
  /// 米
  M,
  /// 千米
  Km,
  /// 英里
  Mi,
  /// 英尺
  Ft,
}

/// GEOSEARCH 选项集合（Garnet.common:GeoSearchOptions）
#[derive(Debug, Clone)]
pub struct GeoSearchOptions {
  /// 原点成员（FROMMEMBER）
  pub from_member: Option<Vec<u8>>,
  /// 原点经度
  pub lon: f64,
  /// 原点纬度
  pub lat: f64,
  /// 半径
  pub radius: f64,
  /// 矩形宽
  pub box_width: f64,
  /// 矩形高
  pub box_height: f64,
  /// 距离单位
  pub unit: Option<GeoDistanceUnitType>,
  /// 排序方向
  pub sort: GeoOrder,
  /// COUNT 值
  pub count_value: i32,
  /// COUNT ANY
  pub with_count_any: bool,
  /// WITHCOORD
  pub with_coord: bool,
  /// WITHDIST
  pub with_dist: bool,
  /// WITHHASH
  pub with_hash: bool,
  /// 原点种类
  pub origin: GeoOriginType,
  /// 形状种类
  pub search_type: GeoSearchType,
}

/// 集群管理器种类（Garnet.server:ManagerType）
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ManagerType {
  /// 迁移管理器
  MigrationManager,
  /// 复制管理器
  ReplicationManager,
  /// 服务器监听器
  ServerListener,
}

/// ZADD 修饰选项（Garnet.common:SortedSetAddOption）
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum SortedSetAddOption {
  /// 无
  None,
  /// 仅更新已存在
  Xx,
  /// 仅添加不存在
  Nx,
  /// 仅更新更小
  Lt,
  /// 仅更新更大
  Gt,
  /// 返回变更计数
  Ch,
  /// 类似 INCR
  Incr,
}

/// 过期条件选项（NX/XX/GT/LT；Garnet.common:ExpireOption）
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ExpireOption {
  /// 无条件
  None,
  /// 仅当无 TTL
  Nx,
  /// 仅当有 TTL
  Xx,
  /// 仅当新 TTL 更大
  Gt,
  /// 仅当新 TTL 更小
  Lt,
}

/// SET/EXPIRE 过期形式（Garnet.common:ExpirationOption）
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ExpirationOption {
  /// 无
  None,
  /// 秒相对
  Ex,
  /// 毫秒相对
  Px,
  /// 秒绝对
  Exat,
  /// 毫秒绝对
  Pxat,
  /// 保留 TTL
  Keepttl,
}

/// GEO/BITFIELD 族错误文案（C# CmdStrings 同名常量；cmd_strings 域由并行
/// 代理扩表，此处本地对齐同一字节文本，避免跨域改文件）
const RESP_ERR_NOT_VALID_RADIUS: &str = "ERR need numeric radius";
const RESP_ERR_RADIUS_IS_NEGATIVE: &str = "ERR radius cannot be negative";
const RESP_ERR_NOT_VALID_GEO_DISTANCE_UNIT: &str =
  "ERR unsupported unit provided. please use M, KM, FT, MI";
const RESP_ERR_NOT_VALID_WIDTH: &str = "ERR need numeric width";
const RESP_ERR_NOT_VALID_HEIGHT: &str = "ERR need numeric height";
const RESP_ERR_HEIGHT_OR_WIDTH_NEGATIVE: &str = "ERR height or width cannot be negative";
const RESP_ERR_COUNT_IS_NOT_POSITIVE: &str = "ERR COUNT must be > 0";
const RESP_ERR_TIMEOUT_IS_NEGATIVE: &str = "ERR timeout is negative";
const RESP_ERR_TIMEOUT_IS_OUT_OF_RANGE: &str = "ERR timeout is out of range";

/// 大小写不敏感匹配（C# EqualsUpperCaseSpanIgnoringCase）
#[inline]
fn eq_upper_ignore_case(raw: &[u8], upper: &[u8]) -> bool {
  raw.eq_ignore_ascii_case(upper)
}

/// 解析态字节访问面（避免扩展层直接触碰 ArgSlice 指针）
pub trait SessionParseStateExtensionAccess {
  /// 下标处参数的 UTF-8 视图
  fn ext_string(&self, idx: usize) -> Option<&str>;
  /// 下标处参数字节；越界返回 None
  fn ext_bytes(&self, idx: usize) -> Option<&[u8]>;
}

impl SessionParseStateExtensionAccess for SessionParseState {
  #[inline]
  fn ext_string(&self, idx: usize) -> Option<&str> {
    from_utf8(self.get_arg_slice_by_ref(idx).as_slice()).ok()
  }

  #[inline]
  fn ext_bytes(&self, idx: usize) -> Option<&[u8]> {
    (idx < self.count).then(|| self.get_arg_slice_by_ref(idx).as_slice())
  }
}

/// libs/server/SessionParseStateExtensions.cs:TryGetInfoMetricsType
pub fn try_get_info_metrics_type(
  parse_state: &SessionParseState,
  idx: usize,
) -> Option<InfoMetricsType> {
  let arg = parse_state.ext_bytes(idx)?;
  let value = if eq_upper_ignore_case(arg, b"SERVER") {
    InfoMetricsType::Server
  } else if eq_upper_ignore_case(arg, b"MEMORY") {
    InfoMetricsType::Memory
  } else if eq_upper_ignore_case(arg, b"CLUSTER") {
    InfoMetricsType::Cluster
  } else if eq_upper_ignore_case(arg, b"REPLICATION") {
    InfoMetricsType::Replication
  } else if eq_upper_ignore_case(arg, b"STATS") {
    InfoMetricsType::Stats
  } else if eq_upper_ignore_case(arg, b"STORE") {
    InfoMetricsType::Store
  } else if eq_upper_ignore_case(arg, b"STOREHASHTABLE") {
    InfoMetricsType::StoreHashtable
  } else if eq_upper_ignore_case(arg, b"STOREREVIV") {
    InfoMetricsType::StoreReviv
  } else if eq_upper_ignore_case(arg, b"PERSISTENCE") {
    InfoMetricsType::Persistence
  } else if eq_upper_ignore_case(arg, b"CLIENTS") {
    InfoMetricsType::Clients
  } else if eq_upper_ignore_case(arg, b"KEYSPACE") {
    InfoMetricsType::Keyspace
  } else if eq_upper_ignore_case(arg, b"MODULES") {
    InfoMetricsType::Modules
  } else if eq_upper_ignore_case(arg, b"BPSTATS") {
    InfoMetricsType::BpStats
  } else if eq_upper_ignore_case(arg, b"CINFO") {
    InfoMetricsType::CInfo
  } else if eq_upper_ignore_case(arg, b"HLOGSCAN") {
    InfoMetricsType::HlogScan
  } else if eq_upper_ignore_case(arg, b"COMMANDSTATS") {
    InfoMetricsType::CommandStats
  } else {
    return None;
  };
  Some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetLatencyMetricsType
pub fn try_get_latency_metrics_type(
  parse_state: &SessionParseState,
  idx: usize,
) -> Option<LatencyMetricsType> {
  let arg = parse_state.ext_bytes(idx)?;
  let value = if eq_upper_ignore_case(arg, b"NET_RS_LAT") {
    LatencyMetricsType::NetRsLat
  } else if eq_upper_ignore_case(arg, b"PENDING_LAT") {
    LatencyMetricsType::PendingLat
  } else if eq_upper_ignore_case(arg, b"TX_PROC_LAT") {
    LatencyMetricsType::TxProcLat
  } else if eq_upper_ignore_case(arg, b"NET_RS_BYTES") {
    LatencyMetricsType::NetRsBytes
  } else if eq_upper_ignore_case(arg, b"NET_RS_OPS") {
    LatencyMetricsType::NetRsOps
  } else if eq_upper_ignore_case(arg, b"NET_RS_LAT_ADMIN") {
    LatencyMetricsType::NetRsLatAdmin
  } else {
    return None;
  };
  Some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetClientName
///
/// 33..=126 可打印字符，空串允许（清名语义）；非 UTF-8 视为失败
pub fn try_get_client_name(parse_state: &SessionParseState, idx: usize) -> Option<&str> {
  let name = parse_state.ext_string(idx)?;
  if name.is_empty() {
    return Some(name);
  }
  name
    .bytes()
    .all(|c| (33..=126).contains(&c))
    .then_some(name)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetClientType
pub fn try_get_client_type(parse_state: &SessionParseState, idx: usize) -> Option<ClientType> {
  let arg = parse_state.ext_bytes(idx)?;
  let value = if eq_upper_ignore_case(arg, b"NORMAL") {
    ClientType::Normal
  } else if eq_upper_ignore_case(arg, b"MASTER") {
    ClientType::Master
  } else if eq_upper_ignore_case(arg, b"REPLICA") {
    ClientType::Replica
  } else if eq_upper_ignore_case(arg, b"PUBSUB") {
    ClientType::Pubsub
  } else if eq_upper_ignore_case(arg, b"SLAVE") {
    ClientType::Slave
  } else {
    ClientType::Invalid
  };
  (value != ClientType::Invalid).then_some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetBitFieldOverflow
pub fn try_get_bit_field_overflow(
  parse_state: &SessionParseState,
  idx: usize,
) -> Option<BitFieldOverflow> {
  let arg = parse_state.ext_bytes(idx)?;
  let value = if eq_upper_ignore_case(arg, b"WRAP") {
    BitFieldOverflow::Wrap
  } else if eq_upper_ignore_case(arg, b"SAT") {
    BitFieldOverflow::Sat
  } else if eq_upper_ignore_case(arg, b"FAIL") {
    BitFieldOverflow::Fail
  } else {
    return None;
  };
  Some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetBitfieldEncoding
///
/// 解析 `i<位宽>` / `u<位宽>`：位宽 > 0，有符号 ≤ 64，无符号 < 64；
/// 数值走 C# TryReadInt64Safe 严格口径（可选符号、拒绝前导零、整体消费）
pub fn try_get_bitfield_encoding(
  parse_state: &SessionParseState,
  idx: usize,
) -> Option<(i64, bool)> {
  let raw = parse_state.ext_bytes(idx)?;
  if raw.len() <= 1 {
    return None;
  }
  let is_signed = match raw[0] {
    b'i' => true,
    b'u' => false,
    _ => return None,
  };
  let bit_count = strict_i64(&raw[1..])?;
  (bit_count > 0
    && (if is_signed {
      bit_count <= 64
    } else {
      bit_count < 64
    }))
  .then_some((bit_count, is_signed))
}

/// libs/server/SessionParseStateExtensions.cs:TryGetBitfieldOffset
///
/// `#<n>` 前缀表示按位宽倍乘（multiplyOffset = true），否则为位偏移；
/// 数值同走严格 i64 口径；值须 ≥ 0
pub fn try_get_bitfield_offset(parse_state: &SessionParseState, idx: usize) -> Option<(i64, bool)> {
  let raw = parse_state.ext_bytes(idx)?;
  let (digits, multiply_offset) = match raw {
    [b'#', rest @ ..] if !rest.is_empty() => (rest, true),
    [] => return None,
    _ => (raw, false),
  };
  let offset = strict_i64(digits)?;
  (offset >= 0).then_some((offset, multiply_offset))
}

/// libs/server/SessionParseStateExtensions.cs:TryGetGeoSearchOptions
///
/// GEOSEARCH 族命令选项解析；返回 (选项, 目标键下标（STORE/STOREDIST），错误文案)。
/// `command` 取 GEOSEARCH/GEOSEARCHSTORE/GEORADIUS[RO]/GEORADIUSBYMEMBER[RO] 之一，
/// `count` 为参数总数，`arg(i)` 取第 i 个参数字节。
pub fn try_get_geo_search_options(
  parse_state: &SessionParseState,
  command: &str,
) -> (Option<GeoSearchOptions>, isize, Option<Vec<u8>>) {
  let count = parse_state.count;
  let is_geosearch = command == "GEOSEARCH";
  let is_geosearchstore = command == "GEOSEARCHSTORE";
  let is_by_member = command == "GEORADIUSBYMEMBER" || command == "GEORADIUSBYMEMBER_RO";
  let is_georadius = command == "GEORADIUS" || command == "GEORADIUS_RO";
  let read_only = is_geosearch || command == "GEORADIUS_RO" || command == "GEORADIUSBYMEMBER_RO";
  let supports_store = command == "GEORADIUS" || is_by_member;

  let mut opts = GeoSearchOptions {
    from_member: None,
    lon: 0.0,
    lat: 0.0,
    radius: 0.0,
    box_width: 0.0,
    box_height: 0.0,
    unit: None,
    sort: GeoOrder::None,
    count_value: 0,
    with_count_any: false,
    with_coord: false,
    with_dist: false,
    with_hash: false,
    origin: GeoOriginType::Undefined,
    search_type: GeoSearchType::Undefined,
  };
  let mut dest_idx: isize = if is_geosearchstore { 0 } else { -1 };
  let mut arg_num_error = false;
  let mut store_dist = false;
  let mut token = 0usize;

  let err = |e: &str| -> Option<Vec<u8>> { Some(e.as_bytes().to_vec()) };
  let num_err = || -> Option<Vec<u8>> {
    Some(format!("ERR wrong number of arguments for '{command}' command").into_bytes())
  };

  // GEORADIUS(BYMEMBER)[RO] 的位置参数（原点 + 半径 + 单位）先行读取
  if is_georadius || is_by_member {
    if is_by_member {
      opts.from_member = parse_state.ext_bytes(token).map(Vec::from);
      token += 1;
      opts.origin = GeoOriginType::FromMember;
    } else {
      match try_geo_lon_lat_pair(parse_state, token) {
        Some((lon, lat, None)) => {
          opts.lon = lon;
          opts.lat = lat;
          token += 2;
          opts.origin = GeoOriginType::FromLonLat;
        }
        Some((_, _, e)) => {
          return (
            None,
            dest_idx,
            e.or_else(|| err(cmd_strings::RESP_ERR_NOT_VALID_FLOAT)),
          );
        }
        None => return (None, dest_idx, err(cmd_strings::RESP_ERR_NOT_VALID_FLOAT)),
      }
    }

    // 半径
    let Some(radius) = parse_state.ext_bytes(token).and_then(strict_double) else {
      return (None, dest_idx, err(RESP_ERR_NOT_VALID_RADIUS));
    };
    token += 1;
    if radius < 0.0 {
      return (None, dest_idx, err(RESP_ERR_RADIUS_IS_NEGATIVE));
    }
    opts.radius = radius;
    opts.search_type = GeoSearchType::ByRadius;
    match parse_state.ext_bytes(token).and_then(geo_distance_unit) {
      Some(unit) => opts.unit = Some(unit),
      None => return (None, dest_idx, err(RESP_ERR_NOT_VALID_GEO_DISTANCE_UNIT)),
    }
    token += 1;
  }

  // 逐 token 选项循环
  while token < count {
    let Some(token_bytes) = parse_state.ext_bytes(token) else {
      break;
    };
    token += 1;

    if is_geosearch || is_geosearchstore {
      if eq_upper_ignore_case(token_bytes, b"FROMMEMBER") {
        if opts.origin != GeoOriginType::Undefined {
          return (
            None,
            dest_idx,
            err(cmd_strings::RESP_ERR_GENERIC_SYNTAX_ERROR),
          );
        }
        if count == token {
          arg_num_error = true;
          break;
        }
        opts.from_member = parse_state.ext_bytes(token).map(Vec::from);
        token += 1;
        opts.origin = GeoOriginType::FromMember;
        continue;
      }
      if eq_upper_ignore_case(token_bytes, b"FROMLONLAT") {
        if opts.origin != GeoOriginType::Undefined {
          return (
            None,
            dest_idx,
            err(cmd_strings::RESP_ERR_GENERIC_SYNTAX_ERROR),
          );
        }
        if count - token < 2 {
          arg_num_error = true;
          break;
        }
        match try_geo_lon_lat_pair(parse_state, token) {
          Some((lon, lat, None)) => {
            opts.lon = lon;
            opts.lat = lat;
          }
          Some((_, _, e)) => {
            return (
              None,
              dest_idx,
              e.or_else(|| err(cmd_strings::RESP_ERR_NOT_VALID_FLOAT)),
            );
          }
          None => return (None, dest_idx, err(cmd_strings::RESP_ERR_NOT_VALID_FLOAT)),
        }
        token += 2;
        opts.origin = GeoOriginType::FromLonLat;
        continue;
      }
      if eq_upper_ignore_case(token_bytes, b"BYRADIUS") {
        if opts.search_type != GeoSearchType::Undefined {
          return (
            None,
            dest_idx,
            err(cmd_strings::RESP_ERR_GENERIC_SYNTAX_ERROR),
          );
        }
        if count - token < 2 {
          arg_num_error = true;
          break;
        }
        match parse_state.ext_bytes(token).and_then(strict_double) {
          Some(radius) => opts.radius = radius,
          None => return (None, dest_idx, err(RESP_ERR_NOT_VALID_RADIUS)),
        }
        token += 1;
        if opts.radius < 0.0 {
          return (None, dest_idx, err(RESP_ERR_RADIUS_IS_NEGATIVE));
        }
        opts.search_type = GeoSearchType::ByRadius;
        match parse_state.ext_bytes(token).and_then(geo_distance_unit) {
          Some(unit) => opts.unit = Some(unit),
          None => return (None, dest_idx, err(RESP_ERR_NOT_VALID_GEO_DISTANCE_UNIT)),
        }
        token += 1;
        continue;
      }
      if eq_upper_ignore_case(token_bytes, b"BYBOX") {
        if opts.search_type != GeoSearchType::Undefined {
          return (
            None,
            dest_idx,
            err(cmd_strings::RESP_ERR_GENERIC_SYNTAX_ERROR),
          );
        }
        opts.search_type = GeoSearchType::ByBox;
        if count - token < 3 {
          arg_num_error = true;
          break;
        }
        match parse_state.ext_bytes(token).and_then(strict_double) {
          Some(w) => opts.box_width = w,
          None => return (None, dest_idx, err(RESP_ERR_NOT_VALID_WIDTH)),
        }
        token += 1;
        match parse_state.ext_bytes(token).and_then(strict_double) {
          Some(h) => opts.box_height = h,
          None => return (None, dest_idx, err(RESP_ERR_NOT_VALID_HEIGHT)),
        }
        token += 1;
        if opts.box_width < 0.0 || opts.box_height < 0.0 {
          return (None, dest_idx, err(RESP_ERR_HEIGHT_OR_WIDTH_NEGATIVE));
        }
        match parse_state.ext_bytes(token).and_then(geo_distance_unit) {
          Some(unit) => opts.unit = Some(unit),
          None => return (None, dest_idx, err(RESP_ERR_NOT_VALID_GEO_DISTANCE_UNIT)),
        }
        token += 1;
        continue;
      }
    }

    if eq_upper_ignore_case(token_bytes, b"ASC") {
      opts.sort = GeoOrder::Ascending;
      continue;
    }
    if eq_upper_ignore_case(token_bytes, b"DESC") {
      opts.sort = GeoOrder::Descending;
      continue;
    }
    if eq_upper_ignore_case(token_bytes, b"COUNT") {
      if count == token {
        arg_num_error = true;
        break;
      }
      // C# TryGetInt 严格口径
      let parsed = parse_state.ext_bytes(token).and_then(strict_i32);
      match parsed {
        Some(count_value) => opts.count_value = count_value,
        None => {
          return (
            None,
            dest_idx,
            err(cmd_strings::RESP_ERR_GENERIC_VALUE_IS_NOT_INTEGER),
          );
        }
      }
      token += 1;
      if opts.count_value <= 0 {
        return (None, dest_idx, err(RESP_ERR_COUNT_IS_NOT_POSITIVE));
      }
      if count > token
        && parse_state
          .ext_bytes(token)
          .is_some_and(|p| eq_upper_ignore_case(p, b"ANY"))
      {
        opts.with_count_any = true;
        token += 1;
      }
      continue;
    }

    if !read_only {
      if supports_store && eq_upper_ignore_case(token_bytes, b"STORE") {
        if count == token {
          arg_num_error = true;
          break;
        }
        token += 1;
        dest_idx = token as isize;
        continue;
      }
      if eq_upper_ignore_case(token_bytes, b"STOREDIST") {
        if supports_store {
          if count == token {
            arg_num_error = true;
            break;
          }
          token += 1;
          dest_idx = token as isize;
        }
        store_dist = true;
        continue;
      }
    }

    if eq_upper_ignore_case(token_bytes, b"WITHCOORD") {
      opts.with_coord = true;
      continue;
    }
    if eq_upper_ignore_case(token_bytes, b"WITHDIST") {
      opts.with_dist = true;
      continue;
    }
    if eq_upper_ignore_case(token_bytes, b"WITHHASH") {
      opts.with_hash = true;
      continue;
    }

    return (
      None,
      dest_idx,
      err(cmd_strings::RESP_ERR_GENERIC_SYNTAX_ERROR),
    );
  }

  // 必选项校验：原点与形状缺一即参数错误
  if opts.origin == GeoOriginType::Undefined || opts.search_type == GeoSearchType::Undefined {
    arg_num_error = true;
  }
  if arg_num_error {
    return (None, dest_idx, num_err());
  }
  if dest_idx != -1 {
    if opts.with_dist || opts.with_coord || opts.with_hash {
      return (
        None,
        dest_idx,
        Some(
          format!(
            "ERR STORE option in {command} is not compatible with WITHDIST, WITHHASH and WITHCOORD options"
          )
          .into_bytes(),
        ),
      );
    }
    opts.with_dist = store_dist;
    // 存入 ZSET 的评分须为距离或哈希之一
    if !opts.with_dist && !opts.with_hash {
      opts.with_hash = true;
    }
  }
  (Some(opts), dest_idx, None)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetManagerType
pub fn try_get_manager_type(parse_state: &SessionParseState, idx: usize) -> Option<ManagerType> {
  let arg = parse_state.ext_bytes(idx)?;
  let value = if eq_upper_ignore_case(arg, b"MIGRATIONMANAGER") {
    ManagerType::MigrationManager
  } else if eq_upper_ignore_case(arg, b"REPLICATIONMANAGER") {
    ManagerType::ReplicationManager
  } else if eq_upper_ignore_case(arg, b"SERVERLISTENER") {
    ManagerType::ServerListener
  } else {
    return None;
  };
  Some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetOperationDirection
pub fn try_get_operation_direction(
  parse_state: &SessionParseState,
  idx: usize,
) -> Option<OperationDirection> {
  let arg = parse_state.ext_bytes(idx)?;
  let value = if eq_upper_ignore_case(arg, b"LEFT") {
    OperationDirection::Left
  } else if eq_upper_ignore_case(arg, b"RIGHT") {
    OperationDirection::Right
  } else {
    return None;
  };
  Some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetSortedSetAddOption
pub fn try_get_sorted_set_add_option(
  parse_state: &SessionParseState,
  idx: usize,
) -> Option<SortedSetAddOption> {
  let arg = parse_state.ext_bytes(idx)?;
  let value = if eq_upper_ignore_case(arg, b"XX") {
    SortedSetAddOption::Xx
  } else if eq_upper_ignore_case(arg, b"NX") {
    SortedSetAddOption::Nx
  } else if eq_upper_ignore_case(arg, b"LT") {
    SortedSetAddOption::Lt
  } else if eq_upper_ignore_case(arg, b"GT") {
    SortedSetAddOption::Gt
  } else if eq_upper_ignore_case(arg, b"CH") {
    SortedSetAddOption::Ch
  } else if eq_upper_ignore_case(arg, b"INCR") {
    SortedSetAddOption::Incr
  } else {
    return None;
  };
  Some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetExpireOption
pub fn try_get_expire_option(parse_state: &SessionParseState, idx: usize) -> Option<ExpireOption> {
  let arg = parse_state.ext_bytes(idx)?;
  if eq_upper_ignore_case(arg, b"NX") {
    Some(ExpireOption::Nx)
  } else if eq_upper_ignore_case(arg, b"XX") {
    Some(ExpireOption::Xx)
  } else if eq_upper_ignore_case(arg, b"GT") {
    Some(ExpireOption::Gt)
  } else if eq_upper_ignore_case(arg, b"LT") {
    Some(ExpireOption::Lt)
  } else {
    None
  }
}

/// libs/server/SessionParseStateExtensions.cs:TryGetSortedSetAggregateType
pub fn try_get_sorted_set_aggregate_type(
  parse_state: &SessionParseState,
  idx: usize,
) -> Option<ZSetAggregate> {
  let arg = parse_state.ext_bytes(idx)?;
  let value = if eq_upper_ignore_case(arg, b"SUM") {
    ZSetAggregate::Sum
  } else if eq_upper_ignore_case(arg, b"MIN") {
    ZSetAggregate::Min
  } else if eq_upper_ignore_case(arg, b"MAX") {
    ZSetAggregate::Max
  } else {
    return None;
  };
  Some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetExpirationOption
pub fn try_get_expiration_option(
  parse_state: &SessionParseState,
  idx: usize,
) -> Option<ExpirationOption> {
  let token = parse_state.ext_bytes(idx)?;
  expiration_option_from_token(token)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetExpirationOptionWithToken
pub fn expiration_option_from_token(token: &[u8]) -> Option<ExpirationOption> {
  let value = if eq_upper_ignore_case(token, b"EX") {
    ExpirationOption::Ex
  } else if eq_upper_ignore_case(token, b"PX") {
    ExpirationOption::Px
  } else if eq_upper_ignore_case(token, b"EXAT") {
    ExpirationOption::Exat
  } else if eq_upper_ignore_case(token, b"PXAT") {
    ExpirationOption::Pxat
  } else if eq_upper_ignore_case(token, b"KEEPTTL") {
    ExpirationOption::Keepttl
  } else {
    return None;
  };
  Some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetGeoDistanceUnit
pub fn geo_distance_unit(raw: &[u8]) -> Option<GeoDistanceUnitType> {
  let value = if eq_upper_ignore_case(raw, b"M") {
    GeoDistanceUnitType::M
  } else if eq_upper_ignore_case(raw, b"KM") {
    GeoDistanceUnitType::Km
  } else if eq_upper_ignore_case(raw, b"MI") {
    GeoDistanceUnitType::Mi
  } else if eq_upper_ignore_case(raw, b"FT") {
    GeoDistanceUnitType::Ft
  } else {
    return None;
  };
  Some(value)
}

/// libs/server/SessionParseStateExtensions.cs:TryGetGeoLonLat
///
/// 经纬度对解析 + 值域校验（C# GeoHash.Longitude/Latitude 边界）；
/// 返回 (经度, 纬度, 错误文案)
pub fn try_get_geo_lon_lat(
  parse_state: &SessionParseState,
  idx: usize,
) -> (Option<f64>, Option<f64>, Option<Vec<u8>>) {
  match try_geo_lon_lat_pair(parse_state, idx) {
    Some((lon, lat, None)) => (Some(lon), Some(lat), None),
    Some((lon, lat, e)) => (Some(lon), Some(lat), e),
    None => (
      None,
      None,
      Some(cmd_strings::RESP_ERR_NOT_VALID_FLOAT.as_bytes().to_vec()),
    ),
  }
}

/// 经纬度对内部实现：Some((lon, lat, 错误))；None 表示浮点解析失败
fn try_geo_lon_lat_pair(
  parse_state: &SessionParseState,
  idx: usize,
) -> Option<(f64, f64, Option<Vec<u8>>)> {
  let lon_raw = parse_state.ext_bytes(idx)?;
  let lat_raw = parse_state.ext_bytes(idx + 1)?;
  let (Some(lon), Some(lat)) = (strict_double(lon_raw), strict_double(lat_raw)) else {
    return Some((
      0.0,
      0.0,
      Some(cmd_strings::RESP_ERR_NOT_VALID_FLOAT.as_bytes().to_vec()),
    ));
  };
  const LONGITUDE_MIN: f64 = -180.0;
  const LONGITUDE_MAX: f64 = 180.0;
  const LATITUDE_MIN: f64 = -85.05112878;
  const LATITUDE_MAX: f64 = 85.05112878;
  if !(LONGITUDE_MIN..=LONGITUDE_MAX).contains(&lon)
    || !(LATITUDE_MIN..=LATITUDE_MAX).contains(&lat)
  {
    return Some((
      lon,
      lat,
      Some(format!("ERR invalid longitude,latitude pair {lon:.6},{lat:.6}").into_bytes()),
    ));
  }
  Some((lon, lat, None))
}

/// libs/server/SessionParseStateExtensions.cs:TryGetTimeout
///
/// 超时（秒）解析：非负且 ≤ i32::MAX/1000（.NET API 毫秒上限）
pub fn try_get_timeout(
  parse_state: &SessionParseState,
  idx: usize,
) -> (Option<f64>, Option<Vec<u8>>) {
  const MAX_TIMEOUT: f64 = i32::MAX as f64 / 1000.0;
  let Some(raw) = parse_state.ext_bytes(idx) else {
    return (
      None,
      Some(
        cmd_strings::RESP_ERR_TIMEOUT_NOT_VALID_FLOAT
          .as_bytes()
          .to_vec(),
      ),
    );
  };
  let Some(timeout) = strict_double(raw) else {
    return (
      None,
      Some(
        cmd_strings::RESP_ERR_TIMEOUT_NOT_VALID_FLOAT
          .as_bytes()
          .to_vec(),
      ),
    );
  };
  if timeout < 0.0 {
    return (None, Some(RESP_ERR_TIMEOUT_IS_NEGATIVE.as_bytes().to_vec()));
  }
  if timeout > MAX_TIMEOUT {
    return (
      None,
      Some(RESP_ERR_TIMEOUT_IS_OUT_OF_RANGE.as_bytes().to_vec()),
    );
  }
  (Some(timeout), None)
}

/// libs/server/SessionParseStateExtensions.cs:ExtractCommandKeys
///
/// 从简化命令元数据的键规格提取参数区中的键（按下标升序）
pub fn extract_command_keys(
  parse_state: &SessionParseState,
  key_specs: &[SimpleRespKeySpec],
  is_sub_command: bool,
) -> Vec<Vec<u8>> {
  let mut keys: Vec<(Vec<u8>, usize)> = Vec::new();
  for spec in key_specs {
    try_append_keys_from_spec(parse_state, spec, is_sub_command, &mut keys);
  }
  keys.sort_by_key(|(_, i)| *i);
  keys.into_iter().map(|(k, _)| k).collect()
}

/// libs/server/SessionParseStateExtensions.cs:ExtractCommandKeysAndFlags
///
/// 从简化命令元数据的键规格提取键 + 标志（按下标升序）
pub fn extract_command_keys_and_flags(
  parse_state: &SessionParseState,
  key_specs: &[SimpleRespKeySpec],
  is_sub_command: bool,
) -> Vec<(Vec<u8>, u8)> {
  let mut keys_flags: Vec<(Vec<u8>, u8, usize)> = Vec::new();
  for spec in key_specs {
    try_append_keys_and_flags_from_spec(parse_state, spec, is_sub_command, &mut keys_flags);
  }
  keys_flags.sort_by_key(|(_, _, i)| *i);
  keys_flags.into_iter().map(|(k, f, _)| (k, f)).collect()
}

/// libs/server/SessionParseStateExtensions.cs:TryAppendKeysFromSpec
fn try_append_keys_from_spec(
  parse_state: &SessionParseState,
  key_spec: &SimpleRespKeySpec,
  is_sub_command: bool,
  keys_to_indexes: &mut Vec<(Vec<u8>, usize)>,
) -> bool {
  let Some((first_idx, last_idx, step)) =
    try_get_key_search_args_from_simple_key_spec(parse_state, key_spec, is_sub_command)
  else {
    return false;
  };
  let mut i = first_idx;
  while i <= last_idx {
    if let Some(bytes) = parse_state.ext_bytes(i).filter(|b| !b.is_empty()) {
      keys_to_indexes.push((bytes.to_vec(), i));
    }
    i += step;
  }
  true
}

/// libs/server/SessionParseStateExtensions.cs:TryAppendKeysAndFlagsFromSpec
fn try_append_keys_and_flags_from_spec(
  parse_state: &SessionParseState,
  key_spec: &SimpleRespKeySpec,
  is_sub_command: bool,
  keys_and_flags: &mut Vec<(Vec<u8>, u8, usize)>,
) -> bool {
  let Some((first_idx, last_idx, step)) =
    try_get_key_search_args_from_simple_key_spec(parse_state, key_spec, is_sub_command)
  else {
    return false;
  };
  let mut i = first_idx;
  while i <= last_idx {
    if let Some(bytes) = parse_state.ext_bytes(i).filter(|b| !b.is_empty()) {
      keys_and_flags.push((bytes.to_vec(), key_spec.flags, i));
    }
    i += step;
  }
  true
}

/// libs/server/SessionParseStateExtensions.cs:TryGetKeySearchArgsFromSimpleKeySpec
///
/// 依简化键规格计算 (firstIdx, lastIdx, step)；返回 None 表示越界 / 关键字未命中
pub fn try_get_key_search_args_from_simple_key_spec(
  parse_state: &SessionParseState,
  key_spec: &SimpleRespKeySpec,
  is_sub_command: bool,
) -> Option<(usize, usize, usize)> {
  let count = parse_state.count as isize;
  // 起始检索下标：负值 = 逆向下标；关键字型需扣除命令名（子命令再扣 1）
  let begin_search_idx = if key_spec.begin_search_index < 0 {
    count + key_spec.begin_search_index as isize
  } else {
    key_spec.begin_search_index as isize - if is_sub_command { 2 } else { 1 }
  };
  if begin_search_idx < 0 || begin_search_idx >= count {
    return None;
  }

  let mut first_key_idx: isize = -1;
  if key_spec.begin_search_is_index_type {
    first_key_idx = begin_search_idx;
  } else {
    // 关键字型：自 begin_search_idx 起按方向扫描关键字（负向下标为逆序扫描；
    // i >= 0 下界护栏 —— C# 逆序越界为未定义读，此处限定在参数区内）
    let step: isize = if key_spec.begin_search_index < 0 {
      -1
    } else {
      1
    };
    let mut i = begin_search_idx;
    while i >= 0 && i < count {
      if parse_state
        .ext_bytes(i as usize)
        .is_some_and(|bytes| eq_upper_ignore_case(bytes, &key_spec.begin_search_keyword))
      {
        first_key_idx = i + 1;
        break;
      }
      i += step;
    }
  }
  if first_key_idx < 0 {
    return None;
  }

  let key_step = key_spec.find_keys_key_step as isize;
  let last_key_idx: isize;
  if key_spec.find_keys_is_range_type {
    if key_spec.find_keys_is_range_limit_type {
      // LIMIT 型：0/1 无截断，n 表示键数的 1/n
      let limit = key_spec.find_keys_last_key_or_limit as isize;
      let key_num = 1 + (count - 1 - first_key_idx) / key_step;
      last_key_idx = if limit == 0 || limit == 1 {
        first_key_idx + (key_num - 1) * key_step
      } else {
        first_key_idx + ((key_num / limit) - 1) * key_step
      };
    } else {
      let raw = key_spec.find_keys_last_key_or_limit as isize;
      last_key_idx = if raw < 0 {
        raw + count
      } else {
        first_key_idx + raw
      };
    }
  } else {
    // KEYNUM 型：键数读自参数区指定下标
    let key_num_idx = (begin_search_idx + key_spec.find_keys_key_num_index as isize) as usize;
    let key_num = parse_state.ext_bytes(key_num_idx)?;
    let key_num: i64 = from_utf8(key_num).ok()?.parse().ok()?;
    first_key_idx += key_spec.find_keys_first_key as isize;
    last_key_idx = first_key_idx + ((key_num as isize - 1) * key_step);
  }

  debug_assert!(last_key_idx < count);
  Some((
    first_key_idx as usize,
    last_key_idx as usize,
    key_step as usize,
  ))
}

/// 简化 RESP 键规格（对齐 RespCommandsInfo 域的 SimpleRespKeySpec 字段面；
/// 该域由并行代理落地，此处以字段视图承接，避免跨域依赖未定型类型）
#[derive(Debug, Clone, Default)]
pub struct SimpleRespKeySpec {
  /// BeginSearch 下标（关键字型为关键字扫描起点；负值表示逆向）
  pub begin_search_index: i32,
  /// BeginSearch 是否下标型（false = 关键字型）
  pub begin_search_is_index_type: bool,
  /// BeginSearch 关键字
  pub begin_search_keyword: Vec<u8>,
  /// FindKeys 步长
  pub find_keys_key_step: i32,
  /// FindKeys 是否区间型（false = KEYNUM 型）
  pub find_keys_is_range_type: bool,
  /// FindKeys 是否 LIMIT 截断型
  pub find_keys_is_range_limit_type: bool,
  /// FindKeys LastKey / Limit / KeyNumIndex 复用字段
  pub find_keys_last_key_or_limit: i32,
  /// FindKeys KeyNum 型首键偏移
  pub find_keys_first_key: i32,
  /// FindKeys KeyNum 型键数下标偏移
  pub find_keys_key_num_index: i32,
  /// 键标志位（KeySpecificationFlags 位图）
  pub flags: u8,
}

/// 严格 f64 解析（C# parseState.TryGetDouble 默认 canBeInfinite: true：
/// INF/+INF/-INF 白名单接受、NaN 拒绝；单一实现位于 parser::session_parse_state）
fn strict_double(raw: &[u8]) -> Option<f64> {
  strict_f64(raw, true)
}

#[cfg(test)]
mod tests {
  use super::*;
  use crate::arg_slice::ArgSlice;

  fn state_of(args: &[&[u8]]) -> SessionParseState {
    let slices: Vec<ArgSlice> = args
      .iter()
      .map(|a| ArgSlice::new(a.as_ptr(), a.len()))
      .collect();
    let mut state = SessionParseState::new();
    state.initialize_with_args(&slices);
    state
  }

  #[test]
  fn info_metrics_types_parse() {
    let state = state_of(&[b"server", b"KEYSPACE", b"nope"]);
    assert_eq!(
      try_get_info_metrics_type(&state, 0),
      Some(InfoMetricsType::Server)
    );
    assert_eq!(
      try_get_info_metrics_type(&state, 1),
      Some(InfoMetricsType::Keyspace)
    );
    assert_eq!(try_get_info_metrics_type(&state, 2), None);
  }

  #[test]
  fn latency_metrics_types_parse() {
    let state = state_of(&[b"net_rs_bytes"]);
    assert_eq!(
      try_get_latency_metrics_type(&state, 0),
      Some(LatencyMetricsType::NetRsBytes)
    );
    assert_ne!(
      try_get_latency_metrics_type(&state, 0),
      Some(LatencyMetricsType::NetRsOps)
    );
  }

  #[test]
  fn client_name_printable_rule() {
    let state = state_of(&[b"ok-name", b"bad name", b""]);
    assert_eq!(try_get_client_name(&state, 0), Some("ok-name"));
    assert_eq!(try_get_client_name(&state, 1), None);
    assert_eq!(try_get_client_name(&state, 2), Some(""));
  }

  #[test]
  fn client_types_parse() {
    let state = state_of(&[b"master", b"PUBSUB", b"other"]);
    assert_eq!(try_get_client_type(&state, 0), Some(ClientType::Master));
    assert_eq!(try_get_client_type(&state, 1), Some(ClientType::Pubsub));
    assert_eq!(try_get_client_type(&state, 2), None);
  }

  #[test]
  fn bitfield_encoding_and_offset() {
    let state = state_of(&[b"i32", b"u64", b"u0", b"#5", b"7", b"i65", b"#"]);
    assert_eq!(try_get_bitfield_encoding(&state, 0), Some((32, true)));
    // C# 约束：无符号位宽须 < 64（u64 非法），u63 合法
    assert_eq!(try_get_bitfield_encoding(&state, 1), None);
    assert_eq!(
      try_get_bitfield_encoding(&state_of(&[b"u63"]), 0),
      Some((63, false))
    );
    assert_eq!(try_get_bitfield_encoding(&state, 2), None);
    assert_eq!(try_get_bitfield_encoding(&state, 5), None);

    assert_eq!(try_get_bitfield_offset(&state, 3), Some((5, true)));
    assert_eq!(try_get_bitfield_offset(&state, 4), Some((7, false)));
    assert_eq!(try_get_bitfield_offset(&state, 6), None);
  }

  #[test]
  fn expire_and_expiration_options() {
    let state = state_of(&[b"gt", b"KEEPTTL", b"pxat", b"bad"]);
    assert_eq!(try_get_expire_option(&state, 0), Some(ExpireOption::Gt));
    assert_eq!(
      try_get_expiration_option(&state, 1),
      Some(ExpirationOption::Keepttl)
    );
    assert_eq!(
      try_get_expiration_option(&state, 2),
      Some(ExpirationOption::Pxat)
    );
    assert_eq!(try_get_expiration_option(&state, 3), None);
  }

  #[test]
  fn timeout_bounds() {
    let state = state_of(&[b"30", b"-1", b"99999999"]);
    let (v, e) = try_get_timeout(&state, 0);
    assert_eq!(v, Some(30.0));
    assert!(e.is_none());
    let (v, e) = try_get_timeout(&state, 1);
    assert!(v.is_none());
    assert_eq!(e.as_deref(), Some(RESP_ERR_TIMEOUT_IS_NEGATIVE.as_bytes()));
    let (_, e) = try_get_timeout(&state, 2);
    assert_eq!(
      e.as_deref(),
      Some(RESP_ERR_TIMEOUT_IS_OUT_OF_RANGE.as_bytes())
    );
  }

  #[test]
  fn operation_direction_and_aggregate() {
    let state = state_of(&[b"left", b"MAX"]);
    assert_eq!(
      try_get_operation_direction(&state, 0),
      Some(OperationDirection::Left)
    );
    assert!(try_get_sorted_set_aggregate_type(&state, 1).is_some());
    assert_eq!(
      try_get_sorted_set_add_option(&state_of(&[b"ch"]), 0),
      Some(SortedSetAddOption::Ch)
    );
    assert_eq!(
      try_get_bit_field_overflow(&state_of(&[b"SAT"]), 0),
      Some(BitFieldOverflow::Sat)
    );
    assert_eq!(try_get_manager_type(&state_of(&[b"nope"]), 0), None);
  }

  #[test]
  fn geo_search_options_full_parse() {
    // GEOSEARCH key FROMLONLAT 1 2 BYRADIUS 30 km ASC COUNT 10 ANY WITHCOORD
    let state = state_of(&[
      b"FROMLONLAT",
      b"1",
      b"2",
      b"BYRADIUS",
      b"30",
      b"KM",
      b"ASC",
      b"COUNT",
      b"10",
      b"ANY",
      b"WITHCOORD",
    ]);
    let (opts, dest, err) = try_get_geo_search_options(&state, "GEOSEARCH");
    assert!(
      err.is_none(),
      "unexpected error: {:?}",
      err.map(|e| String::from_utf8_lossy(&e).into_owned())
    );
    assert_eq!(dest, -1);
    let opts = opts.unwrap();
    assert_eq!(opts.origin, GeoOriginType::FromLonLat);
    assert_eq!(opts.search_type, GeoSearchType::ByRadius);
    assert_eq!(opts.radius, 30.0);
    assert_eq!(opts.unit, Some(GeoDistanceUnitType::Km));
    assert_eq!(opts.sort, GeoOrder::Ascending);
    assert_eq!(opts.count_value, 10);
    assert!(opts.with_count_any);
    assert!(opts.with_coord);
  }

  #[test]
  fn geo_search_requires_origin_and_shape() {
    let state = state_of(&[b"ASC"]);
    let (opts, _, err) = try_get_geo_search_options(&state, "GEOSEARCH");
    assert!(opts.is_none());
    assert_eq!(
      err.as_deref(),
      Some("ERR wrong number of arguments for 'GEOSEARCH' command".as_bytes())
    );
  }

  #[test]
  fn key_search_args_range_type() {
    // MSET key1 val1 key2 val2：begin_search_index=1（扣除命令名后），lastkey=4，step=2
    let state = state_of(&[b"key1", b"val1", b"key2", b"val2"]);
    let spec = SimpleRespKeySpec {
      begin_search_index: 1,
      begin_search_is_index_type: true,
      find_keys_key_step: 2,
      find_keys_is_range_type: true,
      find_keys_last_key_or_limit: -1,
      ..SimpleRespKeySpec::default()
    };
    let keys = extract_command_keys(&state, &[spec], false);
    assert_eq!(keys, vec![b"key1".to_vec(), b"key2".to_vec()]);
  }

  #[test]
  fn key_search_args_keyword_type() {
    let state = state_of(&[b"KEY", b"k1", b"k2"]);
    let spec = SimpleRespKeySpec {
      begin_search_index: 1,
      begin_search_is_index_type: false,
      begin_search_keyword: b"KEY".to_vec(),
      find_keys_key_step: 1,
      find_keys_is_range_type: true,
      find_keys_last_key_or_limit: 1,
      flags: 1,
      ..SimpleRespKeySpec::default()
    };
    let specs = [spec.clone()];
    let pairs = extract_command_keys_and_flags(&state, &specs, false);
    assert_eq!(pairs, vec![(b"k1".to_vec(), 1), (b"k2".to_vec(), 1)]);
    let args = try_get_key_search_args_from_simple_key_spec(&state, &spec, false);
    assert_eq!(args, Some((1, 2, 1)));
  }

  #[test]
  fn key_search_args_reverse_keyword_scan_terminates() {
    // 负下标 = 逆序关键字扫描；关键字未命中时安全终止（下界护栏）
    let state = state_of(&[b"KEY", b"k1", b"k2"]);
    let spec = SimpleRespKeySpec {
      begin_search_index: -1,
      begin_search_is_index_type: false,
      begin_search_keyword: b"MISSING".to_vec(),
      find_keys_key_step: 1,
      find_keys_is_range_type: true,
      find_keys_last_key_or_limit: 1,
      ..SimpleRespKeySpec::default()
    };
    assert_eq!(
      try_get_key_search_args_from_simple_key_spec(&state, &spec, false),
      None
    );

    // 逆序扫描能命中参数区内的关键字（C# 语义：自尾部向前找）
    let spec_hit = SimpleRespKeySpec {
      begin_search_index: -2,
      begin_search_is_index_type: false,
      begin_search_keyword: b"KEY".to_vec(),
      find_keys_key_step: 1,
      find_keys_is_range_type: true,
      find_keys_last_key_or_limit: 1,
      ..SimpleRespKeySpec::default()
    };
    assert_eq!(
      try_get_key_search_args_from_simple_key_spec(&state, &spec_hit, false),
      Some((1, 2, 1))
    );
  }

  #[test]
  fn bitfield_strict_int_semantics() {
    // C# TryReadInt64Safe（allowLeadingZeros: false）：前导零拒绝
    assert_eq!(try_get_bitfield_encoding(&state_of(&[b"i032"]), 0), None);
    assert_eq!(try_get_bitfield_offset(&state_of(&[b"#05"]), 0), None);
    // 可选符号接受（C# TryReadSign 允许 +）
    assert_eq!(
      try_get_bitfield_offset(&state_of(&[b"+5"]), 0),
      Some((5, false))
    );
    assert_eq!(
      try_get_bitfield_offset(&state_of(&[b"#+7"]), 0),
      Some((7, true))
    );
  }

  #[test]
  fn geo_radius_accepts_inf_literal() {
    // C# TryGetDouble 默认 canBeInfinite: true → INF 半径合法（仅拒绝负半径）
    //（GEORADIUSBYMEMBER 以成员为原点，避免 GEORADIUS 的经纬度先行读取）
    let state = state_of(&[b"member", b"INF", b"KM"]);
    let (opts, dest, err) = try_get_geo_search_options(&state, "GEORADIUSBYMEMBER");
    assert!(
      err.is_none(),
      "unexpected: {:?}",
      err.map(|e| String::from_utf8_lossy(&e).into_owned())
    );
    assert_eq!(dest, -1);
    assert_eq!(opts.unwrap().radius, f64::INFINITY);

    // "Infinity" 非 3/4 字节白名单 → not a valid radius
    let state = state_of(&[b"member", b"Infinity", b"KM"]);
    let (opts, _, err) = try_get_geo_search_options(&state, "GEORADIUSBYMEMBER");
    assert!(opts.is_none());
    assert_eq!(err.as_deref(), Some(RESP_ERR_NOT_VALID_RADIUS.as_bytes()));
  }
}