const { query, queryOne } = require('../../db');

const METRIC_FIELD_MAP = {
  '正向有功总电能': 'forward_active_total_energy',
  '正向无功总电能': 'forward_reactive_total_energy',
  '总有功功率': 'total_active_power',
  '总无功功率': 'total_reactive_power',
  A相电压: 'phase_a_voltage',
  B相电压: 'phase_b_voltage',
  C相电压: 'phase_c_voltage',
  A相电流: 'phase_a_current',
  B相电流: 'phase_b_current',
  C相电流: 'phase_c_current',
  总功率因数: 'total_power_factor',
  水表读数: 'water_meter_reading',
  用水量: 'water_meter_reading',
  温度读数: 'temperature_reading',
  平均温度: 'temperature_reading',
  最高温度: 'temperature_reading',
  最低温度: 'temperature_reading'
};

const AGGREGATION_SQL = {
  avg: (field) => `avg(${field})`,
  sum: (field) => `sum(${field})`,
  max: (field) => `max(${field})`,
  min: (field) => `min(${field})`
};

const AGGREGATION_RULES = new Set([...Object.keys(AGGREGATION_SQL), 'subtract']);
const COLLECTION_FIELDS = new Set(Object.values(METRIC_FIELD_MAP));
const LINE_INTERVAL_SECONDS = new Set([5, 10, 15, 30, 60, 300, 600, 1800, 3600, 86400]);

function splitIds(value) {
  if (Array.isArray(value)) {
    return value.map((item) => String(item).trim()).filter(Boolean);
  }
  return String(value || '')
    .split(',')
    .map((item) => item.trim())
    .filter(Boolean);
}

function pad(value) {
  return String(value).padStart(2, '0');
}

function formatDateTime(date) {
  return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())} ${pad(date.getHours())}:${pad(date.getMinutes())}:${pad(date.getSeconds())}`;
}

function normalizeDateTime(value, fallbackDate) {
  if (!value) {
    return formatDateTime(fallbackDate);
  }
  const text = String(value).trim();
  if (/^\d{4}-\d{2}-\d{2}$/.test(text)) {
    return `${text} 00:00:00`;
  }
  if (/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}$/.test(text)) {
    return `${text}:00`;
  }
  if (/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}$/.test(text)) {
    return `${text.replace('T', ' ')}:00`;
  }
  return text.replace('T', ' ').slice(0, 19);
}

function defaultRange() {
  const end = new Date();
  const start = new Date(end.getTime() - 24 * 60 * 60 * 1000);
  return {
    beginTime: formatDateTime(start),
    endTime: formatDateTime(end)
  };
}

function ok(data) {
  return {
    code: 200,
    msg: '查询成功',
    data
  };
}

function emptyLine(beginTime, endTime, metric, interval) {
  return ok({
    xAxis: [],
    series: [],
    devices: [],
    records: [],
    metric,
    beginTime,
    endTime,
    interval
  });
}

async function getMetric(config, metricId) {
  const metric = metricId
    ? await queryOne(
      `select id, type, unit, metric_name, collection_field, aggregation_rule
         from energy_metric_library
        where id = :metricId
          and type = :deviceType
        limit 1`,
      { metricId, deviceType: String(config.deviceType) }
    )
    : null;

  if (metric) {
    return {
      id: metric.id,
      type: String(metric.type),
      name: metric.metric_name,
      unit: metric.unit || '',
      aggregationRule: metric.aggregation_rule || config.defaultAggregationRule,
      field: COLLECTION_FIELDS.has(metric.collection_field) ? metric.collection_field : METRIC_FIELD_MAP[metric.metric_name]
    };
  }

  return {
    id: '',
    type: String(config.deviceType),
    name: config.defaultMetricName,
    unit: config.defaultUnit || '',
    aggregationRule: config.defaultAggregationRule,
    field: config.defaultField
  };
}

function normalizeAggregationRule(rule) {
  return AGGREGATION_RULES.has(rule) ? rule : 'avg';
}

function normalizeInterval(value) {
  if (value === null || value === undefined || value === '') {
    return undefined;
  }
  const interval = Number(value);
  return LINE_INTERVAL_SECONDS.has(interval) ? interval : undefined;
}

function buildReportTimeSql(interval) {
  if (!interval) {
    return "date_format(report_time, '%Y-%m-%d %H:%i:%s')";
  }
  return `date_format(from_unixtime(floor(unix_timestamp(report_time) / ${interval}) * ${interval}), '%Y-%m-%d %H:%i:%s')`;
}

function buildLocationMaps(rows) {
  const byId = new Map(rows.map((row) => [String(row.id), row]));
  const nameMap = new Map();
  const locationMap = new Map();

  function pathOf(row) {
    const names = [];
    let current = row;
    const visited = new Set();
    while (current && !visited.has(String(current.id))) {
      visited.add(String(current.id));
      if (current.name && current.isDevice !== '1' && current.isDeviceGroup !== '1') {
        names.unshift(current.name);
      }
      current = byId.get(String(current.pid));
    }
    return names.join(' / ');
  }

  rows.forEach((row) => {
    if (row.deviceId) {
      nameMap.set(row.deviceId, row.name || row.deviceId);
      locationMap.set(row.deviceId, pathOf(row));
    }
  });

  return { nameMap, locationMap };
}

function createMetricLineService(config) {
  async function devices() {
    const rows = await query(
      `select device_id as deviceId,
              name
         from \`floorInfo\`
        where del_flag = '0'
          and is_device = '1'
          and device_type = :deviceType
          and device_id is not null
          and device_id <> ''
        order by create_time asc, id asc`,
      { deviceType: String(config.deviceType) }
    );

    return ok(rows.map((row) => ({
      label: row.name || row.deviceId,
      value: row.deviceId
    })));
  }

  async function line(queryParams = {}) {
    const range = defaultRange();
    const beginTime = normalizeDateTime(queryParams.beginTime, new Date(range.beginTime));
    const endTime = normalizeDateTime(queryParams.endTime, new Date(range.endTime));
    const deviceIds = splitIds(queryParams.deviceIds);
    const metric = await getMetric(config, queryParams.metricId);
    const interval = normalizeInterval(queryParams.interval);

    if (!metric.field || !deviceIds.length) {
      return emptyLine(beginTime, endTime, metric, interval);
    }

    const aggregationRule = normalizeAggregationRule(metric.aggregationRule);
    const reportTimeSql = buildReportTimeSql(interval);
    const params = { beginTime, endTime };
    const placeholders = deviceIds.map((deviceId, index) => {
      params[`deviceId${index}`] = deviceId;
      return `:deviceId${index}`;
    });

    const nodeRows = await query(
      `select id,
              pid,
              name,
              is_device as isDevice,
              is_device_group as isDeviceGroup,
              device_id as deviceId
         from \`floorInfo\`
        where del_flag = '0'
        order by create_time asc, id asc`
    );
    const { nameMap, locationMap } = buildLocationMaps(nodeRows);

    let rows;
    if (!interval) {
      rows = await query(
        `select device_id as deviceId,
                ${reportTimeSql} as reportTime,
                ${metric.field} as value
           from device_collection_data_info
          where report_time >= :beginTime
            and report_time <= :endTime
            and ${metric.field} is not null
            and device_id in (${placeholders.join(', ')})
          order by report_time asc, id asc, device_id asc`,
        params
      );
    } else if (aggregationRule === 'subtract') {
      rows = await query(
        `select deviceId,
                reportTime,
                max(case when rnDesc = 1 then metricValue end) - max(case when rnAsc = 1 then metricValue end) as value
           from (
             select device_id as deviceId,
                    ${reportTimeSql} as reportTime,
                    ${metric.field} as metricValue,
                    row_number() over (
                      partition by device_id, ${reportTimeSql}
                      order by report_time asc, id asc
                    ) as rnAsc,
                    row_number() over (
                      partition by device_id, ${reportTimeSql}
                      order by report_time desc, id desc
                    ) as rnDesc
               from device_collection_data_info
              where report_time >= :beginTime
                and report_time <= :endTime
                and ${metric.field} is not null
                and device_id in (${placeholders.join(', ')})
           ) source
          group by deviceId, reportTime
          order by reportTime asc, deviceId asc`,
        params
      );
    } else {
      rows = await query(
        `select device_id as deviceId,
                ${reportTimeSql} as reportTime,
                ${AGGREGATION_SQL[aggregationRule](metric.field)} as value
           from device_collection_data_info
          where report_time >= :beginTime
            and report_time <= :endTime
            and ${metric.field} is not null
            and device_id in (${placeholders.join(', ')})
          group by device_id, reportTime
          order by reportTime asc, device_id asc`,
        params
      );
    }

    const xAxis = [...new Set(rows.map((row) => row.reportTime))];
    const byDevice = new Map();
    rows.forEach((row) => {
      if (!byDevice.has(row.deviceId)) {
        byDevice.set(row.deviceId, new Map());
      }
      byDevice.get(row.deviceId).set(row.reportTime, Number(row.value));
    });

    const series = deviceIds.map((deviceId) => {
      const values = byDevice.get(deviceId) || new Map();
      return {
        deviceId,
        name: nameMap.get(deviceId) || deviceId,
        type: 'line',
        smooth: true,
        connectNulls: true,
        data: xAxis.map((time) => values.get(time) ?? null)
      };
    });
    const records = rows.map((row) => ({
      deviceId: row.deviceId,
      deviceName: nameMap.get(row.deviceId) || row.deviceId,
      deviceLocation: locationMap.get(row.deviceId) || '',
      reportTime: row.reportTime,
      metricName: metric.name,
      metricUnit: metric.unit,
      value: row.value === null || row.value === undefined ? null : Number(row.value)
    }));

    return ok({
      xAxis,
      series,
      devices: deviceIds.map((deviceId) => ({
        deviceId,
        name: nameMap.get(deviceId) || deviceId
      })),
      metric: {
        id: metric.id,
        name: metric.name,
        unit: metric.unit,
        aggregationRule
      },
      records,
      beginTime,
      endTime,
      interval
    });
  }

  return {
    devices,
    line
  };
}

module.exports = {
  createMetricLineService
};