document.addEventListener('DOMContentLoaded', () => {
    
    if (typeof Chart === 'undefined') {
        console.error('Chart.js is not loaded.');
        return;
    }

    const colorPrimary      = '#1e3a8a';
    const colorSuccess      = '#10b981';
    const colorWarning      = '#f59e0b';
    const colorDanger       = '#ef4444';
    const colorBorder       = '#e5e7eb';
    const colorPrimaryLight = '#3b82f6';
    const fontFamily        = "'Inter', sans-serif";

    if (Chart.defaults && Chart.defaults.font) {
        Chart.defaults.font.family = fontFamily;
    }
    if (Chart.defaults) {
        Chart.defaults.color = '#6b7280';
    }

    // =================================================================
    // CHART 1: Training Loss per Step (data RIIL dari notebook)
    // 2523 steps, 3 epoch, sampled every 50 steps for readability
    // =================================================================
    const canvasLoss = document.getElementById('lossChart');
    if (canvasLoss) {
        // Data riil dari log training notebook (diambil setiap 50 steps)
        const realSteps = [10,50,100,150,200,250,300,350,400,450,500,550,600,650,700,750,800,841,
                           900,950,1000,1050,1100,1150,1200,1250,1300,1350,1400,1450,1500,1550,1600,1650,1682,
                           1750,1800,1850,1900,1950,2000,2050,2100,2150,2200,2250,2300,2350,2400,2450,2500,2523];
        const realLoss  = [4.8127,2.8853,2.3493,1.6928,0.9643,0.9488,0.8374,0.7111,0.4475,0.4417,0.4857,0.3596,0.3565,0.3267,0.3244,0.3280,0.2946,0.2821,
                           0.2810,0.3034,0.2860,0.2676,0.2576,0.2720,0.2680,0.2777,0.2646,0.2511,0.2587,0.2467,0.2462,0.2448,0.2456,0.2375,0.2404,
                           0.2416,0.2385,0.2265,0.2259,0.2335,0.2343,0.2313,0.2248,0.2353,0.2177,0.2229,0.2238,0.2254,0.2303,0.2259,0.2199,0.2226];

        // Epoch boundary markers (steps 841 = epoch 1 end, 1682 = epoch 2 end, 2523 = epoch 3 end)
        new Chart(canvasLoss.getContext('2d'), {
            type: 'line',
            data: {
                labels: realSteps,
                datasets: [
                    {
                        label: 'Training Loss (per step)',
                        data: realLoss,
                        borderColor: colorWarning,
                        backgroundColor: 'rgba(245, 158, 11, 0.1)',
                        borderWidth: 2,
                        tension: 0.4,
                        fill: true,
                        pointRadius: 0,
                        pointHoverRadius: 5
                    }
                ]
            },
            options: {
                responsive: true,
                maintainAspectRatio: false,
                plugins: {
                    legend: { position: 'top' },
                    tooltip: {
                        callbacks: {
                            label: ctx => ` Loss: ${ctx.parsed.y.toFixed(4)}`
                        }
                    },
                    annotation: {}
                },
                scales: {
                    y: {
                        beginAtZero: true,
                        grid: { color: colorBorder },
                        title: { display: true, text: 'Training Loss' }
                    },
                    x: {
                        grid: { display: false },
                        title: { display: true, text: 'Step' },
                        ticks: {
                            maxTicksLimit: 10,
                            callback: function(val, idx) {
                                const step = this.getLabelForValue(val);
                                // Mark epoch boundaries
                                if (step == 841) return 'Ep.1 End';
                                if (step == 1682) return 'Ep.2 End';
                                if (step == 2523) return 'Ep.3 End';
                                return step;
                            }
                        }
                    }
                }
            }
        });
    }

    // =================================================================
    // CHART 2: Training Loss per Epoch (rata-rata)
    // Epoch 1 avg: ~1.86, Epoch 2 avg: ~0.27, Epoch 3 avg: ~0.23
    // =================================================================
    const canvasScore = document.getElementById('scoreChart');
    if (canvasScore) {
        new Chart(canvasScore.getContext('2d'), {
            type: 'bar',
            data: {
                labels: ['Epoch 1', 'Epoch 2', 'Epoch 3'],
                datasets: [
                    {
                        label: 'Rata-rata Training Loss per Epoch',
                        data: [1.86, 0.27, 0.23],
                        backgroundColor: [
                            'rgba(239, 68, 68, 0.7)',
                            'rgba(245, 158, 11, 0.7)',
                            'rgba(16, 185, 129, 0.7)'
                        ],
                        borderColor: [colorDanger, colorWarning, colorSuccess],
                        borderWidth: 2,
                        borderRadius: 8
                    }
                ]
            },
            options: {
                responsive: true,
                maintainAspectRatio: false,
                plugins: {
                    legend: { position: 'top' },
                    tooltip: {
                        callbacks: {
                            label: ctx => ` Avg Loss: ${ctx.parsed.y.toFixed(4)}`
                        }
                    }
                },
                scales: {
                    y: {
                        beginAtZero: true,
                        grid: { color: colorBorder },
                        title: { display: true, text: 'Training Loss' }
                    },
                    x: { grid: { display: false } }
                }
            }
        });
    }

});