/**
 * Creates and manages all indicator-related logic for the chart.
 * @param {Object} chart - The Lightweight Charts instance.
 * @param {Array<Object>} baseCandleData - A reference to the array holding the chart's BASE 1m candle data.
 * @returns {Object} A manager object with public methods to control indicators.
 */
function createIndicatorManager(chart, baseCandleData) {
    // This holds the candle data currently displayed on the chart (e.g., 5m, 10m)
    let currentAggregatedData = [];

    // Defines the 4 slots available in the UI for indicators.
    const indicatorSlots = [
        { id: 1, cellId: 'indicator-cell-1', series: [], definition: null, params: {} },
        { id: 2, cellId: 'indicator-cell-2', series: [], definition: null, params: {} },
        { id: 3, cellId: 'indicator-cell-3', series: [], definition: null, params: {} },
        { id: 4, cellId: 'indicator-cell-4', series: [], definition: null, params: {} },
    ];

    // Pre-defined colors for the indicator lines.
    const colors = {
        bb1: { upper: '#FF9800', lower: '#FF9800' }, // Orange
        bb2: { upper: '#2196F3', lower: '#2196F3' }, // Blue
        bb3: { upper: '#9C27B0', lower: '#9C27B0' }, // Purple
        default: ['#FF5722', '#03A9F4', '#8BC34A', '#F44336'] // Fallback colors for other indicators
    };

    /**
     * Populates the dropdown menus in each indicator cell.
     */
    function populateDropdowns() {
        indicatorSlots.forEach(slot => {
            const cell = document.getElementById(slot.cellId);
            if (!cell) return;

            const select = document.createElement('select');
            select.innerHTML = `<option value="">-- Select Indicator --</option>`;
            AVAILABLE_INDICATORS.forEach(ind => {
                select.innerHTML += `<option value="${ind.name}">${ind.label}</option>`;
            });

            const controlsContainer = document.createElement('div');
            controlsContainer.className = 'indicator-controls';

            cell.innerHTML = ''; // Clear previous content
            cell.appendChild(select);
            cell.appendChild(controlsContainer);

            select.addEventListener('change', (e) => {
                const indicatorName = e.target.value;
                loadIndicator(slot.id, indicatorName);
            });
        });
    }

    /**
     * Loads a new indicator into a specified slot.
     * @param {number} slotId - The ID of the slot (1-4).
     * @param {string} indicatorName - The name of the indicator to load (e.g., 'SMA').
     */
    function loadIndicator(slotId, indicatorName) {
        const slot = indicatorSlots.find(s => s.id === slotId);
        if (!slot) return;

        // Clean up any previous indicator series in this slot
        slot.series.forEach(s => chart.removeSeries(s));
        slot.series = [];
        
        slot.definition = null;
        slot.params = {};
        
        const controlsContainer = document.querySelector(`#${slot.cellId} .indicator-controls`);
        controlsContainer.innerHTML = '';

        if (!indicatorName) return;

        const definition = AVAILABLE_INDICATORS.find(ind => ind.name === indicatorName);
        if (!definition) return;

        slot.definition = definition;
        
        // Create UI controls for the indicator's parameters
        definition.params.forEach(param => {
            const label = document.createElement('label');
            label.textContent = param.label || param.name;
            label.style.fontSize = '12px';
            
            const input = document.createElement('input');
            input.type = param.type;
            input.value = param.defaultValue;
            if (param.min !== undefined) input.min = param.min;
            if (param.step !== undefined) input.step = param.step;
            input.className = 'input-field';
            input.placeholder = param.name;
            slot.params[param.name] = input.type === 'number' ? parseFloat(input.value) : input.value;

            let debounceTimer;
            input.addEventListener('input', () => {
                clearTimeout(debounceTimer);
                debounceTimer = setTimeout(() => {
                    slot.params[param.name] = input.type === 'number' ? parseFloat(input.value) : input.value;
                    updateIndicator(slot.id);
                }, 500); 
            });
            const controlGroup = document.createElement('div');
            controlGroup.style.display = 'flex';
            controlGroup.style.flexDirection = 'column';
            controlGroup.appendChild(label);
            controlGroup.appendChild(input);
            controlsContainer.appendChild(controlGroup);
        });

        updateIndicator(slot.id);
    }

    /**
     * Recalculates and redraws the lines for a specific indicator.
     * @param {number} slotId - The ID of the slot to update.
     */
    function updateIndicator(slotId) {
        const slot = indicatorSlots.find(s => s.id === slotId);
        
        const candleDataForCalc = (slot.definition.usesBaseData) ? baseCandleData : currentAggregatedData;

        if (!slot || !slot.definition || candleDataForCalc.length === 0) {
            return;
        }

        // Clean up previous series before creating new ones
        slot.series.forEach(s => chart.removeSeries(s));
        slot.series = [];

        console.log(`Recalculating ${slot.definition.name} for slot ${slot.id} on ${candleDataForCalc.length} candles.`);
        
        const indicatorResult = slot.definition.calculateFull(candleDataForCalc, slot.params);

        // Handle multi-line indicators like Bollinger Bands
        if (typeof indicatorResult === 'object' && !Array.isArray(indicatorResult)) {
            Object.keys(indicatorResult).forEach(key => {
                const seriesData = indicatorResult[key];
                const bandName = key.split('_')[0]; 
                const bandType = key.split('_')[1]; 
                
                const series = chart.addLineSeries({
                    color: colors[bandName] ? colors[bandName][bandType] : colors.default[slot.id - 1],
                    lineWidth: 2,
                    title: `${slot.definition.label} - ${key}`,
                    lastValueVisible: false,
                    priceLineVisible: false,
                });
                series.setData(seriesData);
                slot.series.push(series);
            });
        } else { // Handle single-line indicators like SMA/EMA
            const series = chart.addLineSeries({
                color: colors.default[slot.id - 1],
                lineWidth: 2,
                title: slot.definition.label,
            });
            series.setData(indicatorResult);
            slot.series.push(series);
        }
    }
    
    /**
     * Internal function to recalculate all active indicators.
     */
    function recalculateAllIndicators() {
         indicatorSlots.forEach(slot => {
            if (slot.definition) {
                updateIndicator(slot.id);
            }
        });
    }

    /**
     * Sets the candle data for indicators and triggers a full recalculation.
     * @param {Array<Object>} aggregatedCandleData - The candle data for the currently selected timeframe.
     */
    function recalculateAllAfterHistory(aggregatedCandleData) {
         currentAggregatedData = aggregatedCandleData;
         recalculateAllIndicators();
    }

    /**
     * Updates all indicators in response to a new candle closing.
     * @param {Array<Object>} aggregatedCandleData - The latest candle data for the currently selected timeframe.
     */
    function updateIndicatorsOnNewCandle(aggregatedCandleData) {
        currentAggregatedData = aggregatedCandleData;
        recalculateAllIndicators();
    }

    // Public API for the manager
    return {
        populateDropdowns,
        recalculateAllAfterHistory,
        updateIndicatorsOnNewCandle
    };
}