import { Buffer } from 'buffer/'

import { lookupTableA } from '../tables/table'
import { lookupTable41, lookupTable42, lookupTable43, lookupTable44, lookupTable45, lookupTable47 } from '../tables/table-4'
import { calculateForecastTime } from '../utils/calculate-forecast-time'

/**
 * @description Returns a template generator for the given template number
 * @param template Template number
 * @returns Template generator
 */
export const getTemplate4 = (template: number) => {
  switch (template) {
    case 0:
      return template40
    case 2:
      return template42

    default:
      throw new Error(`Template 4.${template} not defined`)
  }
}

/**
 * @description Returns a template map for the given template number
 * @param table Template number
 * @returns Template Map
 */
export const lookupTemplate4 = (template: number) => {
  switch (template) {
    case 0:
      return lookupTemplate40
    case 2:
      return lookupTemplate42

    default:
      throw new Error(`Template 4.${template} lookup table not defined`)
  }
}

/**
 * Product Definition Template 4.0
 *
 * [Read more...](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_temp4-0.shtml)
 */
const template40 = (section: Buffer) => {
  return {
    /** Paramater category (see Code [Table 4.1](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-1.shtml)) */
    parameterCategory: section.readUInt8(9),
    /** Paramater number (see Code [Table 4.2](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-2.shtml)) */
    parameterNumber: section.readUInt8(10),
    /** Type of generating process (see Code [Table 4.3](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-3.shtml)) */
    genProcessType: section.readUInt8(11),
    /** Background generating process identifier (defined by originating centre) */
    backgroundGenProcess: section.readUInt8(12),
    /** Forecast generating process identified (see Code [ON388 Table A](https://www.nco.ncep.noaa.gov/pmb/docs/on388/tablea.html)) */
    forecastGenProcess: section.readUInt8(13),
    /** Hours after reference time data cutoff */
    hoursAfterRefTime: section.readUInt16BE(14),
    /** Minutes after reference time data cutoff */
    minAfterRefTime: section.readUInt8(16),
    /** Indicator of unit of time range (see Code [Table 4.4](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-4.shtml)) */
    unitOfTimeRangeIndicator: section.readUInt8(17),
    /** Forecast time offset */
    forecastTimeOffset: section.readUInt32BE(18),
    /** Type of first fixed surface (see Code [Table 4.5](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-5.shtml)) */
    surface1Type: section.readUInt8(22),
    /** Scale factor of first fixed surface */
    surface1Scale: section.readUInt8(23),
    /** Scaled value of first fixed surface */
    surface1Value: section.readUInt32BE(24),
    /** Type of second fixed surface (see Code [Table 4.5](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-5.shtml)) */
    surface2Type: section.readUInt8(28),
    /** Scale factor of second fixed surface */
    surface2Scale: section.readUInt8(29),
    /** Scaled value of second fixed surface */
    surface2Value: section.readUInt32BE(30)
  }
}

const lookupTemplate40 = (discipline: number, refTime: Date, templateValues: ReturnType<typeof template40>) => {
  const { parameterCategory, parameterNumber, surface1Type, surface1Scale, surface1Value, surface2Type, surface2Scale, surface2Value, ...newValues } = templateValues

  const category = lookupTable41(discipline, parameterCategory)
  const values = lookupTable42(discipline, parameterCategory, parameterNumber)

  const surface1 = { ...lookupTable45(surface1Type), scale: surface1Scale, value: surface1Value }
  const surface2 = { ...lookupTable45(surface2Type), scale: surface2Scale, value: surface2Value }

  const unitOfTimeRangeIndicator = lookupTable44(newValues.unitOfTimeRangeIndicator)

  return {
    ...newValues,
    /** Paramater */
    paramater: { category, ...values },
    /** Type of generating process */
    genProcessType: lookupTable43(newValues.genProcessType),
    /** Forecast generating process identified */
    forecastGenProcess: lookupTableA(newValues.forecastGenProcess),
    /** Indicator of unit of time range */
    unitOfTimeRangeIndicator,
    /** Forecast time */
    forecastTime: calculateForecastTime(refTime, newValues.forecastTimeOffset, unitOfTimeRangeIndicator),
    /** First fixed surface */
    surface1,
    /** Second fixed surface */
    surface2
  }
}

/**
 * Product Definition Template 4.2
 *
 * [Read more...](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_temp4-2.shtml)
 */
const template42 = (section: Buffer) => {
  return {
    /** Paramater category (see Code [Table 4.1](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-1.shtml)) */
    parameterCategory: section.readUInt8(9),
    /** Paramater number (see Code [Table 4.2](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-2.shtml)) */
    parameterNumber: section.readUInt8(10),
    /** Type of generating process (see Code [Table 4.3](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-3.shtml)) */
    genProcessType: section.readUInt8(11),
    /** Background generating process identifier (defined by originating centre) */
    backgroundGenProcess: section.readUInt8(12),
    /** Forecast generating process identified (see Code [ON388 Table A](https://www.nco.ncep.noaa.gov/pmb/docs/on388/tablea.html)) */
    forecastGenProcess: section.readUInt8(13),
    /** Hours after reference time data cutoff */
    hoursAfterRefTime: section.readUInt16BE(14),
    /** Minutes after reference time data cutoff */
    minAfterRefTime: section.readUInt8(16),
    /** Indicator of unit of time range (see Code [Table 4.4](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-4.shtml)) */
    unitOfTimeRangeIndicator: section.readUInt8(17),
    /** Forecast time offset */
    forecastTimeOffset: section.readUInt32BE(18),
    /** Type of first fixed surface (see Code [Table 4.5](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-5.shtml)) */
    surface1Type: section.readUInt8(22),
    /** Scale factor of first fixed surface */
    surface1Scale: section.readUInt8(23),
    /** Scaled value of first fixed surface */
    surface1Value: section.readUInt32BE(24),
    /** Type of second fixed surface (see Code [Table 4.5](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-5.shtml)) */
    surface2Type: section.readUInt8(28),
    /** Scale factor of second fixed surface */
    surface2Scale: section.readUInt8(29),
    /** Scaled value of second fixed surface */
    surface2Value: section.readUInt32BE(30),
    /** Derived forecast (see Code [Table 4.7](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-7.shtml)) */
    derivedForecast: section.readUInt8(34),
    /** Number of forecasts in the ensemble */
    numberOfForecast: section.readUInt8(35)
  }
}

const lookupTemplate42 = (discipline: number, refTime: Date, templateValues: ReturnType<typeof template42>) => {
  const { parameterCategory, parameterNumber, surface1Type, surface1Scale, surface1Value, surface2Type, surface2Scale, surface2Value, ...newValues } = templateValues

  const category = lookupTable41(discipline, parameterCategory)
  const values = lookupTable42(discipline, parameterCategory, parameterNumber)

  const surface1 = { ...lookupTable45(surface1Type), scale: surface1Scale, value: surface1Value }
  const surface2 = { ...lookupTable45(surface2Type), scale: surface2Scale, value: surface2Value }

  const unitOfTimeRangeIndicator = lookupTable44(newValues.unitOfTimeRangeIndicator)

  return {
    ...newValues,
    /** Paramater */
    paramater: { category, ...values },
    /** Type of generating process */
    genProcessType: lookupTable43(newValues.genProcessType),
    /** Forecast generating process identified */
    forecastGenProcess: lookupTableA(newValues.forecastGenProcess),
    /** Indicator of unit of time range */
    unitOfTimeRangeIndicator,
    /** Forecast time */
    forecastTime: calculateForecastTime(refTime, newValues.forecastTimeOffset, unitOfTimeRangeIndicator),
    /** First fixed surface */
    surface1,
    /** Second fixed surface */
    surface2,
    /** Derived forecast */
    derivedForecast: lookupTable47(newValues.derivedForecast)
  }
}