"use strict";

/**
 * Prompt 解析器 - 从命令输出中提取指标
 *
 * 分层策略：
 * 1. 正则匹配（快，简单场景够用）
 * 2. 返回原始输出（解析失败时让用户看原始数据）
 */

/**
 * 华为/H3C 交换机命令解析配置
 */
const HUAWEI_H3C_PATTERNS = {
  cpu_usage: {
    // CPU 使用率：多种可能的格式
    patterns: [
      /CPU\s+Usage\s*:\s*(\d+)%/i,
      /CPU\s+utilization.*one\s+minute:\s*(\d+)%/i,
      /CPU\s+Usage\s+:\s*(\d+)%/i,
    ],
    default: null,
  },
  memory_usage: {
    // 内存使用率：多种格式
    patterns: [
      /Memory\s+Using\s+Percentage\s+Is:\s*(\d+)%/i,
      /Memory\s+utilization.*:\s*(\d+)%/i,
    ],
    default: null,
  },
};

/**
 * 解析单行指标
 * @param {string} output - 命令原始输出
 * @param {object} config - { patterns: RegExp[], default: any }
 * @returns {any} 解析结果
 */
function parseMetric(output, config) {
  if (!output || !config?.patterns) return config?.default ?? null;

  for (const pattern of config.patterns) {
    const match = output.match(pattern);
    if (match) {
      return parseFloat(match[1]);
    }
  }
  return config.default ?? null;
}

/**
 * 解析端口状态
 * @param {string} output - 命令输出
 * @returns {object} { up_count, down_count, ports }
 */
function parseInterfaceBrief(output) {
  const lines = output.split("\n");
  const ports = [];
  let upCount = 0;
  let downCount = 0;

  for (const line of lines) {
    // 匹配端口行：GigabitEthernet0/0/1        up       up
    const portMatch = line.match(/^(GigabitEthernet|FastEthernet|Ethernet)(\S+)\s+(\w+)\s+(\w+)/);
    if (portMatch) {
      const phy = portMatch[3].toLowerCase();
      const proto = portMatch[4].toLowerCase();
      ports.push({
        name: portMatch[1] + portMatch[2],
        phy,
        protocol: proto,
        is_up: phy === "up" && proto === "up",
      });
      if (phy === "up") upCount++;
      else downCount++;
    }
  }

  return { up_count: upCount, down_count: downCount, ports };
}

/**
 * 解析电源状态
 * @param {string} output - 命令输出
 * @returns {object} { normal_count, abnormal_count }
 */
function parsePowerStatus(output) {
  const lines = output.split("\n");
  let normalCount = 0;
  let abnormalCount = 0;

  for (const line of lines) {
    // 匹配电源状态行
    if (/Normal|Supply|OK/i.test(line)) {
      normalCount++;
    } else if (/Absent|Fault|Error/i.test(line)) {
      abnormalCount++;
    }
  }

  return { normal_count: normalCount, abnormal_count: abnormalCount };
}

/**
 * 清理交换机输出
 * @param {string} output - 原始输出
 * @returns {string} 清理后的输出
 */
function cleanOutput(output) {
  return output
    // 移除提示符
    .replace(/<\w+[-A-Za-z0-9]*>/g, "")
    // 移除分页标记
    .replace(/---- More ----/g, "")
    // 移除命令回显
    .replace(/^[^\r\n]*\r?\n/, "")
    // 移除空行
    .replace(/\n{3,}/g, "\n\n")
    .trim();
}

/**
 * 使用 prompt 风格解析交换机输出
 * @param {string} output - 原始命令输出
 * @param {object} context - { catalog_id, device_info }
 * @returns {object} 结构化指标
 */
function parseSwitchOutput(output, context = {}) {
  const cleaned = cleanOutput(output);
  const lines = cleaned.split("\n");

  const metrics = {
    cpu_usage: null,
    memory_usage: null,
    port_status: [],
    power_status: [],
    fan_status: [],
  };

  // 解析 CPU
  metrics.cpu_usage = parseMetric(cleaned, HUAWEI_H3C_PATTERNS.cpu_usage);

  // 解析内存
  metrics.memory_usage = parseMetric(cleaned, HUAWEI_H3C_PATTERNS.memory_usage);

  // 解析端口
  metrics.port_status = parseInterfaceBrief(cleaned);

  // 解析电源
  metrics.power_status = parsePowerStatus(cleaned);

  // 原始输出（便于调试）
  metrics._raw_output = cleaned;
  metrics._parse_errors = [];

  if (metrics.cpu_usage === null) {
    metrics._parse_errors.push("cpu_usage: 无法解析");
  }
  if (metrics.memory_usage === null) {
    metrics._parse_errors.push("memory_usage: 无法解析");
  }

  return metrics;
}

module.exports = {
  parseMetric,
  parseInterfaceBrief,
  parsePowerStatus,
  cleanOutput,
  parseSwitchOutput,
};