/**
 * Shared Dashboard Update Module
 * Used by: sys_set.html, sys_rf.html, sys_ts.html, sys_psip.html, log_output.html, status_info.html
 * 
 * This module provides a common refreshDashboard() function that updates
 * the summary dashboard cards with status data from the backend.
 * 
 * For status_info.html which already fetches data, use updateDashboardCards() 
 * to update cards without making an additional AJAX call.
 */
(function() {
    'use strict';

    // Power decimal lookup table
    var POWER_DECIMALS = ["00","05","10","15","20","25","30","35","40","45","50","55","60","65","70","75","80","85","90","95"];
    
    // Input source labels
    var INPUT_SOURCES = ["ASI1","ASI2","EAS","Tuner","TSoIP","None"];

    /**
     * Calculate frequency from channel number
     * @param {number} chan - Channel number (2-83)
     * @returns {number} Frequency in MHz
     */
    function calcFrequency(chan) {
        var freq = 0;
        if (chan >= 2 && chan <= 6) {
            freq = (chan - 2) * 6 + 57;
            if (freq > 69) freq += 4;
        } else if (chan >= 7 && chan <= 13) {
            freq = 177 + 6 * (chan - 7);
        } else if (chan >= 14 && chan <= 83) {
            freq = 473 + (chan - 14) * 6;
        }
        return freq;
    }

    /**
     * Convert temperature based on unit
     * @param {number} rawValue - Raw temperature value
     * @param {number} unit - 0 = Fahrenheit, 1 = Celsius
     * @returns {number|string} Temperature in Fahrenheit
     */
    function convertTemperature(rawValue, unit) {
        if (unit === 0) {
            return rawValue; // Already Fahrenheit
        } else {
            return (rawValue * 1.8 + 32).toFixed(2); // Celsius to Fahrenheit
        }
    }

    /**
     * Helper function to set card value and status
     * @param {string} id - Element ID for the value
     * @param {string} dotId - Element ID for the status dot
     * @param {*} value - Value to display
     * @param {string} status - Status class (ok, warn, err, off, neutral)
     */
    function setCard(id, dotId, value, status) {
        var el = document.getElementById(id);
        var dot = document.getElementById(dotId);
        if (el) {
            el.innerText = value;
            el.className = "summary-value value-" + status;
        }
        if (dot) {
            dot.className = "status-dot status-" + status;
        }
    }

    /**
     * Get SNR status based on value
     * @param {string} snr - SNR value or "N/A"
     * @returns {string} Status class
     */
    function getSnrStatus(snr) {
        if (snr === "N/A") return 'off';
        var val = parseFloat(snr);   // already carries the +10 dB display offset
        if (val >= 37) return 'ok';
        if (val >= 30) return 'warn';
        return 'err';
    }

    /**
     * Get IMD status (UIMD/LIMD)
     * @param {string} imd - IMD value or "N/A"
     * @returns {string} Status class
     */
    function getImdStatus(imd) {
        if (imd === "N/A") return 'off';
        return parseFloat(imd) >= 47 ? 'ok' : 'err';
    }

    /**
     * Update all dashboard cards with provided data
     * Use this when you already have the data (e.g., from status_info.html)
     * 
     * @param {Object} data - Dashboard data object
     * @param {number} data.freqVal - Frequency in MHz
     * @param {string} data.snr - SNR value
     * @param {string} data.limd - LIMD value
     * @param {string} data.uimd - UIMD value
     * @param {string} data.inputSrc - Input source label
     * @param {string} data.inputStatus - Input status (OK/Err)
     * @param {string} data.bitrate - Bitrate value
     * @param {string} data.temp - Temperature value
     * @param {string} data.agc - AGC status (On/Off)
     * @param {string} data.ctrl - Control mode (Remote/Local)
     * @param {number} data.rfStat - RF switch status (1=On, 0=Off)
     * @param {string} data.finalPower - Output power string
     */
    window.updateDashboardCards = function(data) {
        setCard('sum_freq', 'dot_freq', data.freqVal, 'neutral');
        setCard('sum_snr', 'dot_snr', data.snr, getSnrStatus(data.snr));
        setCard('sum_uimd', 'dot_uimd', data.uimd, getImdStatus(data.uimd));
        setCard('sum_limd', 'dot_limd', data.limd, getImdStatus(data.limd));
        setCard('sum_input', 'dot_input', data.inputSrc, 'neutral');
        setCard('sum_input_status', 'dot_input_status', data.inputStatus, 
                (data.inputStatus === "OK") ? 'ok' : 'err');
        setCard('sum_bitrate', 'dot_bitrate', data.bitrate, 'neutral');
        setCard('sum_temp', 'dot_temp', data.temp, 
                (parseFloat(data.temp) >= 160) ? 'err' : 'ok');
        setCard('sum_agc', 'dot_agc', data.agc, 
                (data.agc === "On") ? 'ok' : 'off');
        setCard('sum_control', 'dot_control', data.ctrl, 
                (data.ctrl.toUpperCase() === "REMOTE") ? 'neutral' : 'warn');
        setCard('sum_rf', 'dot_rf', (data.rfStat === 1) ? "On" : "Off", 
                (data.rfStat === 1) ? 'ok' : 'off');
        setCard('sum_outpow', 'dot_outpow', data.finalPower, 'ok');
    };

    /**
     * Main function to refresh the dashboard
     * Fetches system state and updates all summary cards
     */
    window.refreshDashboard = function() {
        var queryData = "State_SysState=&sys_rf=&atscmode=&";

        $.get("atsc_status_cfg.cgi?" + queryData, function(data, status, xhr) {
            // Handle case where data is a JSON object (e.g., session expired)
            if (typeof data === 'object' && data !== null) {
                if (data.error === 'session_expired' && data.redirect) {
                    window.location.href = data.redirect;
                    return;
                }
                console.error('Received JSON error response instead of expected data:', data);
                return;
            }

            // Ensure data is a string before attempting to split
            var responseText = typeof data === 'string' ? data : (xhr && xhr.responseText) ? xhr.responseText : String(data || '');
            if (typeof responseText !== 'string') {
                console.error('Dashboard data is not a string:', typeof responseText, responseText);
                return;
            }

            var table = responseText.split("|");
            if (!Array.isArray(table) || table.length < 2) {
                console.error('Invalid dashboard data format:', responseText);
                return;
            }

            var form = table[0].split("#");
            if (!Array.isArray(form)) {
                console.error('Invalid form data format:', table[0]);
                return;
            }

            var rf_form = table[1].split("#");
            if (!Array.isArray(rf_form)) {
                console.error('Invalid rf_form data format:', table[1]);
                return;
            }

            var atscmod_para = table[2] ? table[2].split("#") : ["", ""];
            if (!Array.isArray(atscmod_para)) {
                console.error('Invalid atscmod_para data format:', table[2]);
                return;
            }

            // FSSI refresh mode check
            var ab_modenum = Number(form[25]);
            var temp_unit = Number(form[26]);

            // Frequency
            var chan = Number(form[7]);
            var freqVal = calcFrequency(chan);

            // SNR: half-dB from the app plus the fixed +10 dB display offset.
            var snr = (ab_modenum === 1) ? "N/A" : (Number(form[11]) / 2 + 10).toFixed(1);

            // LIMD / UIMD: half-dB from the app plus the fixed +11 dB display offset.
            // Rounding the sum and then appending the half misreports odd half-dB
            // values by 1 dB, so format the sum directly.
            var limd = (ab_modenum === 1) ? "N/A" : (Number(form[12]) / 2 + 11).toFixed(1);
            var uimd = (ab_modenum === 1) ? "N/A" : (Number(form[13]) / 2 + 11).toFixed(1);

            // Input source
            var inputIdx = Number(form[1]);
            if (inputIdx < 0 || inputIdx > 5) inputIdx = 5;
            var inputSrc = INPUT_SOURCES[inputIdx];

            // Input status
            var inputStatus = (Number(form[2]) === 0) ? "OK" : "Err";

            // Bitrate
            var bitrate = form[4];

            // Temperature with unit conversion
            var temp = convertTemperature(Number(form[5]), temp_unit);

            // AGC
            var agc = (Number(form[3]) === 0) ? "Off" : "On";

            // Control
            var ctrl = (Number(form[14]) === 0) ? "Remote" : "Local";

            // RF Switch
            var rfStat = Number(rf_form[4]);

            // Output Power
            var p_sign = (Number(rf_form[1]) === 0) ? "+" : "-";
            var p_int = Number(rf_form[2]);
            var p_dec = POWER_DECIMALS[Number(rf_form[3])] || "00";
            var finalPower = p_sign + p_int + "." + p_dec;

            // Update all cards using the shared function
            window.updateDashboardCards({
                freqVal: freqVal,
                snr: snr,
                limd: limd,
                uimd: uimd,
                inputSrc: inputSrc,
                inputStatus: inputStatus,
                bitrate: bitrate,
                temp: temp,
                agc: agc,
                ctrl: ctrl,
                rfStat: rfStat,
                finalPower: finalPower
            });
        }).fail(function(jqXHR, textStatus, errorThrown) {
            console.error('Failed to fetch dashboard data:', textStatus, errorThrown);
            console.log('Response text:', jqXHR.responseText);
            console.log('Status code:', jqXHR.status);
        });
    };

    // Export helper functions for status_info.html
    window.DashboardHelpers = {
        calcFrequency: calcFrequency,
        convertTemperature: convertTemperature,
        setCard: setCard,
        getSnrStatus: getSnrStatus,
        getImdStatus: getImdStatus,
        POWER_DECIMALS: POWER_DECIMALS,
        INPUT_SOURCES: INPUT_SOURCES
    };

})();