/**
 * Chart Management Module
 * Handles Chart.js initialization and updates
 */
class ChartManager {
    constructor(calculator) {
        this.calculator = calculator;
        this.charts = {};
    }

    initializeCharts() {
        // Check if Chart.js is available
        if (typeof Chart === 'undefined') {
            console.error('Chart.js library not loaded. Charts will not be available.');
            this.showChartError('Chart.js library failed to load. Please refresh the page.');
            return;
        }

        try {
            // ROI Progression Chart (replaces Instance Growth Chart)
            const roiCanvas = document.getElementById('instanceGrowthChart');
            if (!roiCanvas) {
                console.error('ROI progression chart canvas not found');
                return;
            }
            const roiCtx = roiCanvas.getContext('2d');
            this.charts.roiProgression = new Chart(roiCtx, {
                type: 'line',
                data: { labels: [], datasets: [] },
                options: {
                    responsive: true,
                    maintainAspectRatio: false,
                    plugins: {
                        legend: { position: 'top' },
                        title: { display: true, text: 'ROI Progression Over Time' }
                    },
                    scales: {
                        y: {
                            title: { display: true, text: 'ROI (%)' },
                            grid: {
                                color: function(context) {
                                    return context.tick.value === 0 ? 'rgba(0,0,0,0.5)' : 'rgba(0,0,0,0.1)';
                                }
                            }
                        },
                        x: {
                            title: { display: true, text: 'Month' }
                        }
                    }
                }
            });

            // Net Position Chart (replaces simple Revenue Chart)
            const netPositionCanvas = document.getElementById('revenueChart');
            if (!netPositionCanvas) {
                console.error('Net position chart canvas not found');
                return;
            }
            const netPositionCtx = netPositionCanvas.getContext('2d');
            this.charts.netPosition = new Chart(netPositionCtx, {
                type: 'line',
                data: { labels: [], datasets: [] },
                options: {
                    responsive: true,
                    maintainAspectRatio: false,
                    plugins: {
                        legend: { position: 'top' },
                        title: { display: true, text: 'Net Financial Position (Break-Even Analysis)' }
                    },
                    scales: {
                        y: {
                            title: { display: true, text: 'Net Position (CHF)' },
                            grid: {
                                color: function(context) {
                                    return context.tick.value === 0 ? 'rgba(0,0,0,0.8)' : 'rgba(0,0,0,0.1)';
                                }
                            }
                        },
                        x: {
                            title: { display: true, text: 'Month' }
                        }
                    }
                }
            });

            // Model Comparison Chart (replaces generic Cash Flow Chart)
            const modelComparisonCanvas = document.getElementById('cashFlowChart');
            if (!modelComparisonCanvas) {
                console.error('Model comparison chart canvas not found');
                return;
            }
            const modelComparisonCtx = modelComparisonCanvas.getContext('2d');
            this.charts.modelComparison = new Chart(modelComparisonCtx, {
                type: 'bar',
                data: { labels: [], datasets: [] },
                options: {
                    responsive: true,
                    maintainAspectRatio: false,
                    plugins: {
                        legend: { position: 'top' },
                        title: { display: true, text: 'Investment Model Performance Comparison' }
                    },
                    scales: {
                        y: {
                            beginAtZero: true,
                            title: { display: true, text: 'Total Return (CHF)' }
                        },
                        x: {
                            title: { display: true, text: 'Growth Scenario' }
                        }
                    }
                }
            });
        } catch (error) {
            console.error('Error initializing charts:', error);
            this.showChartError('Failed to initialize charts. Please refresh the page.');
        }
    }

    showChartError(message) {
        // Show error message in place of charts
        const chartContainers = ['instanceGrowthChart', 'revenueChart', 'cashFlowChart'];
        chartContainers.forEach(containerId => {
            const container = document.getElementById(containerId);
            if (container) {
                container.style.display = 'flex';
                container.style.justifyContent = 'center';
                container.style.alignItems = 'center';
                container.style.minHeight = '300px';
                container.style.backgroundColor = '#f8f9fa';
                container.style.border = '1px solid #dee2e6';
                container.style.borderRadius = '4px';
                container.innerHTML = `<div class="text-muted text-center"><i class="bi bi-exclamation-triangle"></i><br>${message}</div>`;
            }
        });
    }

    updateCharts() {
        try {
            const scenarios = Object.keys(this.calculator.results);
            if (scenarios.length === 0 || !this.charts.roiProgression) return;

            const colors = {
                conservative: '#28a745',
                moderate: '#ffc107', 
                aggressive: '#dc3545'
            };

            // Get month labels
            const maxMonths = Math.max(...scenarios.map(s => this.calculator.monthlyData[s].length));
            const monthLabels = Array.from({ length: maxMonths }, (_, i) => `M${i + 1}`);

            // Update ROI Progression Chart
            this.charts.roiProgression.data.labels = monthLabels;
            this.charts.roiProgression.data.datasets = scenarios.map(scenario => ({
                label: `${this.calculator.scenarios[scenario].name} (${this.calculator.results[scenario].investmentModel})`,
                data: this.calculator.monthlyData[scenario].map(d => d.roiPercent),
                borderColor: colors[scenario],
                backgroundColor: colors[scenario] + '20',
                tension: 0.4,
                pointBackgroundColor: this.calculator.monthlyData[scenario].map(d => 
                    d.roiPercent >= 0 ? colors[scenario] : '#dc3545'
                )
            }));
            this.charts.roiProgression.update();

            // Update Net Position Chart (Break-Even Analysis)
            this.charts.netPosition.data.labels = monthLabels;
            this.charts.netPosition.data.datasets = scenarios.map(scenario => ({
                label: `${this.calculator.scenarios[scenario].name} Net Position`,
                data: this.calculator.monthlyData[scenario].map(d => d.netPosition),
                borderColor: colors[scenario],
                backgroundColor: colors[scenario] + '20',
                tension: 0.4,
                fill: {
                    target: 'origin',
                    above: colors[scenario] + '10',
                    below: '#dc354510'
                }
            }));
            this.charts.netPosition.update();

            // Update Model Comparison Chart
            const scenarioLabels = scenarios.map(s => this.calculator.scenarios[s].name);
            const currentInvestmentModel = Object.values(this.calculator.results)[0]?.investmentModel || 'direct';
            
            // Show comparison with both models for the same scenarios
            this.charts.modelComparison.data.labels = scenarioLabels;
            this.charts.modelComparison.data.datasets = [{
                label: `${currentInvestmentModel === 'loan' ? 'Loan Model' : 'Direct Investment'} - Final Return`,
                data: scenarios.map(scenario => this.calculator.results[scenario].cspRevenue),
                backgroundColor: scenarios.map(scenario => colors[scenario] + '80'),
                borderColor: scenarios.map(scenario => colors[scenario]),
                borderWidth: 2
            }];
            
            // Add performance metrics for direct investment
            if (currentInvestmentModel === 'direct') {
                this.charts.modelComparison.data.datasets.push({
                    label: 'Performance Bonus Impact',
                    data: scenarios.map(scenario => 
                        this.calculator.results[scenario].avgPerformanceBonus * 
                        this.calculator.results[scenario].cspRevenue
                    ),
                    backgroundColor: '#17a2b8',
                    borderColor: '#17a2b8',
                    borderWidth: 2
                });
            }
            
            this.charts.modelComparison.update();
        } catch (error) {
            console.error('Error updating charts:', error);
        }
    }
}