// Access to InfluxDB 1.8 via HTTP using InfluxQL
//
// IMPORTANT: InfluxDB 1.8 vs 2.0 Data Schema Differences:
// - InfluxDB 1.8: Only stores LA_max, LA_min, LA_eq (all in dB)  
// - InfluxDB 2.0: Additionally stores E10tel_eq as pre-calculated linear value (10^(LA_max/10))
//
// This implementation converts LA_max to E10tel_eq at runtime to maintain
// compatibility with the Flux version while ensuring correct logarithmic averaging.

import axios from 'axios'
import { DateTime } from 'luxon'
import { logit, logerror } from '../utilities/logit.js'
import { returnOnError } from "../utilities/reporterror.js"

// InfluxDB 1.8 Configuration
let INFLUXHOST = process.env.INFLUXHOST || "localhost"
let INFLUXPORT = process.env.INFLUXPORT || 8086
let INFLUXUSER = process.env.INFLUXUSER || ""
let INFLUXPASS = process.env.INFLUXPASS || ""
let INFLUXDB = process.env.INFLUXDB || "sensor_data"

// InfluxDB 1.8 URLs
const INFLUXURL_READ = `http://${INFLUXHOST}:${INFLUXPORT}/query`
const INFLUXURL_WRITE = `http://${INFLUXHOST}:${INFLUXPORT}/write`

/**
 * Execute InfluxQL query against InfluxDB 1.8
 * @param {string} query - InfluxQL query string
 * @returns {Object} - {values: [], err: null}
 */
const influxRead = async (query) => {
    let start = DateTime.now()
    logit(`ReadInflux from ${INFLUXURL_READ}`)
    let erg = { values: [], err: null}
    
    try {
        const params = {
            db: INFLUXDB,
            q: query,
            epoch: 'ms' // Return timestamps in milliseconds
        }
        
        // Add authentication if provided
        if (INFLUXUSER && INFLUXPASS) {
            params.u = INFLUXUSER
            params.p = INFLUXPASS
        }
        
        let ret = await axios({
            method: 'get',
            url: INFLUXURL_READ,
            params: params,
            timeout: 10000,
        })
        
        if (ret.status !== 200) {
            return returnOnError(erg, 'RESPSTATUS', influxRead.name, ret.status)
        }
        
        // InfluxDB 1.8 returns JSON format
        if (ret.data.error) {
            return returnOnError(erg, ret.data.error, influxRead.name)
        }
        
        erg.values = ret.data.results
    } catch (e) {
        return returnOnError(erg, e, influxRead.name)
    }
    
    logit(`Influx read time: ${start.diffNow('seconds').toObject().seconds * -1} sec`)
    return erg
}

/**
 * Write data to InfluxDB 1.8
 * @param {string} data - Line protocol data
 * @returns {Object} - Response object
 */
const influxWrite = async (data) => {
    let start = DateTime.now()
    let ret
    
    try {
        const params = {
            db: INFLUXDB,
            precision: 'ms'
        }
        
        // Add authentication if provided
        if (INFLUXUSER && INFLUXPASS) {
            params.u = INFLUXUSER
            params.p = INFLUXPASS
        }
        
        ret = await axios({
            method: 'post',
            url: INFLUXURL_WRITE,
            params: params,
            data: data,
            headers: {
                'Content-Type': 'text/plain; charset=utf-8'
            },
            timeout: 10000,
        })
        
        if (ret.status !== 204) {
            logerror(`doWrite2API Status: ${ret.status}`)
        }
    } catch (e) {
        logerror(`doWrite2API ${e}`)
    }
    
    logit(`Influx-Write-Time: ${start.diffNow('seconds').toObject().seconds * -1} sec`)
    return ret
}

/**
 * Helper function to transform InfluxDB 1.8 result to format compatible with Flux version
 * @param {Array} series - InfluxDB series data
 * @returns {Array} - Transformed data array
 */
const transformInfluxResult = (series) => {
    if (!series || !series.length) return []
    
    const result = []
    
    series.forEach(serie => {
        if (!serie.values) return
        
        const columns = serie.columns
        const timeIndex = columns.indexOf('time')
        
        serie.values.forEach(row => {
            const record = {}
            columns.forEach((col, index) => {
                if (col === 'time') {
                    // Convert timestamp to ISO string for compatibility
                    record._time = new Date(row[index]).toISOString()
                } else {
                    record[col] = row[index]
                }
            })
            result.push(record)
        })
    })
    
    return result
}

/**
 * Execute query and transform results
 * @param {Object} ret - Return object
 * @param {string} query - InfluxQL query
 * @returns {Object} - Transformed result
 */
const fetchFromInflux = async (ret, query) => {
    let { values, err } = await influxRead(query)
    if (err) {
        if (err.toString().includes('400')) {
            return returnOnError(ret, 'SYNTAXURL', fetchFromInflux.name)
        } else {
            return returnOnError(ret, err, fetchFromInflux.name)
        }
    }
    
    if (!values || !values.length || !values[0].series) {
        return returnOnError(ret, 'NODATA', fetchFromInflux.name)
    }
    
    ret.values = transformInfluxResult(values[0].series)
    return ret
}

/**
 * Fetch current/historical sensor data from InfluxDB 1.8
 * @param {Object} opts - Options object
 * @param {string} opts.sensorid - Sensor ID
 * @param {string} opts.start - Start time (e.g., "start: -1h")
 * @param {string} opts.stop - Stop time (e.g., "stop: now()")
 * @param {number} opts.sort - Sort order (1 for ascending, -1 for descending)
 * @returns {Object} - {err: null, values: []}
 */
export const fetchActData = async (opts) => {
    let ret = { err: null, values: [] }
    
    // Convert Flux time format to InfluxQL format
    let startTime = opts.start.replace('start: ', '').trim()
    let stopTime = opts.stop.replace('stop: ', '').trim()
    
    // Build sorting clause
    let orderClause = ''
    if (opts.sort) {
        if (opts.sort === 1) {
            orderClause = 'ORDER BY time ASC'
        } else if (opts.sort === -1) {
            orderClause = 'ORDER BY time DESC'
        }
    }
    
    // InfluxQL query to get LA_max for a sensor within time range
    // Note: In InfluxDB 1.8 we only have LA_max, not E10tel_eq like in 2.0
    const query = `
        SELECT "LA_max", "LA_min", "LA_eq"
        FROM "measurements"
        WHERE "sid" = '${opts.sensorid}' 
        AND time >= ${startTime} 
        AND time <= ${stopTime}
        ${orderClause}
    `
    
    // Get the data and transform it to include E10tel_eq equivalent
    const result = await fetchFromInflux(ret, query)
    
    if (result.err) {
        return result
    }
    
    // Transform data to add E10tel_eq field for compatibility with Flux version
    // E10tel_eq = 10^(LA_max/10)
    result.values = result.values.map(record => ({
        ...record,
        E10tel_eq: record.LA_max !== null && record.LA_max !== undefined 
            ? Math.pow(10, record.LA_max / 10) 
            : null
    }))
    
    return result
}

/**
 * Helper function to calculate logarithmic average for decibel values
 * For decibel values, we need to:
 * 1. Convert dB to linear scale (10^(dB/10))
 * 2. Calculate arithmetic mean of linear values
 * 3. Convert back to dB (10 * log10(mean))
 * @param {Array} values - Array of decibel values
 * @returns {number} - Logarithmic average in dB
 */
const calculateLogMean = (values) => {
    if (!values || values.length === 0) return null
    
    // Convert dB to linear scale, calculate mean, convert back to dB
    const linearSum = values.reduce((sum, val) => {
        if (val !== null && val !== undefined) {
            return sum + Math.pow(10, val / 10)
        }
        return sum
    }, 0)
    
    const validCount = values.filter(val => val !== null && val !== undefined).length
    if (validCount === 0) return null
    
    const linearMean = linearSum / validCount
    return 10 * Math.log10(linearMean)
}

/**
 * Fetch noise averaging data from InfluxDB 1.8 with proper logarithmic averaging for LAmax
 * @param {Object} opts - Options object
 * @param {string} opts.sensorid - Sensor ID
 * @param {string} opts.start - Start time
 * @param {string} opts.stop - Stop time
 * @param {number} opts.peak - Peak threshold for counting
 * @param {boolean} opts.long - Return full data or just summarized
 * @returns {Object} - {err: null, values: []}
 */
export const fetchNoiseAVGData = async (opts) => {
    let ret = { err: null, values: [] }
    
    // Convert Flux time format to InfluxQL format
    let startTime = opts.start.replace('start: ', '').trim()
    let stopTime = opts.stop.replace('stop: ', '').trim()
    
    // Since InfluxQL doesn't support complex joins like Flux, we need to make multiple queries
    // and combine the results in JavaScript
    
    // Query 1: Get LA_max data aggregated by hour for E10tel calculation
    // In InfluxDB 1.8, we only have LA_max (dB), need to convert to E10tel equivalent
    const queryLAmaxForE10 = `
        SELECT "LA_max", time
        FROM "measurements"
        WHERE "sid" = '${opts.sensorid}' 
        AND time >= ${startTime} 
        AND time <= ${stopTime}
        AND "LA_max" IS NOT NULL
        ORDER BY time ASC
    `
    
    // Query 2: Same query for peak counting (we'll process the same data)
    const queryLAmaxForPeaks = queryLAmaxForE10
    
    try {
        // Execute LA_max query (we use the same data for both E10tel calculation and peak counting)
        let { values: lamaxValues, err: lamaxErr } = await influxRead(queryLAmaxForE10)
        if (lamaxErr) {
            return returnOnError(ret, lamaxErr, fetchNoiseAVGData.name)
        }
        
        if (!lamaxValues || !lamaxValues.length || !lamaxValues[0].series) {
            return returnOnError(ret, 'NODATA', fetchNoiseAVGData.name)
        }
        
        // Transform LA_max results
        const lamaxData = transformInfluxResult(lamaxValues[0].series)
        
        // Group LA_max data by hour and calculate:
        // 1. E10tel equivalent values (10^(LA_max/10))
        // 2. Peak counting
        // 3. Statistics for n_AVG calculation
        const hourlyData = {}
        
        lamaxData.forEach(record => {
            const timestamp = new Date(record._time)
            const hourKey = new Date(timestamp.getFullYear(), timestamp.getMonth(), 
                                   timestamp.getDate(), timestamp.getHours()).toISOString()
            
            if (!hourlyData[hourKey]) {
                hourlyData[hourKey] = {
                    time: hourKey,
                    lamaxValues: [],
                    e10telValues: [], // Converted LA_max to E10tel equivalent
                    peakCount: 0
                }
            }
            
            const lamax = record.LA_max
            if (lamax !== null && lamax !== undefined) {
                // Store original LA_max value
                hourlyData[hourKey].lamaxValues.push(lamax)
                
                // Convert LA_max (dB) to E10tel equivalent: 10^(LA_max/10)
                const e10tel = Math.pow(10, lamax / 10)
                hourlyData[hourKey].e10telValues.push(e10tel)
                
                // Count peaks
                if (lamax >= opts.peak) {
                    hourlyData[hourKey].peakCount++
                }
            }
        })
        
        // Calculate final results for each hour
        const combinedResults = []
        
        Object.values(hourlyData).forEach(hourData => {
            const result = {
                _time: hourData.time,
                count: hourData.e10telValues.length,
                peakcount: hourData.peakCount
            }
            
            // Calculate E10tel statistics
            if (hourData.e10telValues.length > 0) {
                // Sum of E10tel values
                result.n_sum = hourData.e10telValues.reduce((sum, val) => sum + val, 0)
                
                // Mean of E10tel values, then convert back to dB for n_AVG
                // This matches the Flux version: mean(E10tel_eq) then 10*log10(mean)
                const e10telMean = result.n_sum / hourData.e10telValues.length
                result.n_AVG = 10.0 * Math.log10(e10telMean)
            }
            
            // Add additional fields if opts.long is true
            if (opts.long) {
                result.LA_max_values = hourData.lamaxValues
                result.LA_max_log_avg = calculateLogMean(hourData.lamaxValues)
                result.E10tel_values = hourData.e10telValues
            }
            
            combinedResults.push(result)
        })
        
        // Sort by time
        combinedResults.sort((a, b) => new Date(a._time) - new Date(b._time))
        
        // Filter results based on opts.long
        if (!opts.long) {
            ret.values = combinedResults.map(record => ({
                _time: record._time,
                peakcount: record.peakcount,
                n_AVG: record.n_AVG
            }))
        } else {
            ret.values = combinedResults
        }
        
    } catch (e) {
        return returnOnError(ret, e, fetchNoiseAVGData.name)
    }
    
    return ret
}

// Export write function for compatibility
export { influxWrite }