(() => {
  const dataElement = document.getElementById("dashboard-data");
  if (!dataElement) {
    return;
  }

  let state = {};
  try {
    state = JSON.parse(dataElement.textContent || "{}");
  } catch (error) {
    console.error("Failed to parse dashboard data", error);
    return;
  }

  const statusElement = document.getElementById("dashboard-status");
  const summaryContainer = document.getElementById("summary-metrics");
  const summaryEmpty = document.getElementById("summary-empty");
  const scenarioTableBody = document.querySelector("#scenario-table tbody");
  const scenarioEmpty = document.getElementById("scenario-table-empty");
  const overallMetricsList = document.getElementById("overall-metrics");
  const overallMetricsEmpty = document.getElementById("overall-metrics-empty");
  const recentList = document.getElementById("recent-simulations");
  const recentEmpty = document.getElementById("recent-simulations-empty");
  const maintenanceList = document.getElementById("upcoming-maintenance");
  const maintenanceEmpty = document.getElementById(
    "upcoming-maintenance-empty"
  );
  const refreshButton = document.getElementById("refresh-dashboard");
  const costChartCanvas = document.getElementById("cost-chart");
  const costChartEmpty = document.getElementById("cost-chart-empty");
  const activityChartCanvas = document.getElementById("activity-chart");
  const activityChartEmpty = document.getElementById("activity-chart-empty");

  let costChartInstance = null;
  let activityChartInstance = null;

  const setStatus = (message, variant = "success") => {
    if (!statusElement) {
      return;
    }
    if (!message) {
      statusElement.hidden = true;
      statusElement.textContent = "";
      statusElement.classList.remove("success", "error");
      return;
    }
    statusElement.textContent = message;
    statusElement.hidden = false;
    statusElement.classList.toggle("success", variant === "success");
    statusElement.classList.toggle("error", variant !== "success");
  };

  const renderSummaryMetrics = () => {
    if (!summaryContainer || !summaryEmpty) {
      return;
    }
    summaryContainer.innerHTML = "";
    const metrics = Array.isArray(state.summary_metrics)
      ? state.summary_metrics
      : [];
    metrics.forEach((metric) => {
      const card = document.createElement("article");
      card.className = "metric-card";
      card.innerHTML = `
        <span class="metric-label">${metric.label}</span>
        <span class="metric-value">${metric.value}</span>
      `;
      summaryContainer.appendChild(card);
    });
    summaryEmpty.hidden = metrics.length > 0;
  };

  const renderScenarioTable = () => {
    if (!scenarioTableBody || !scenarioEmpty) {
      return;
    }
    scenarioTableBody.innerHTML = "";
    const rows = Array.isArray(state.scenario_rows) ? state.scenario_rows : [];
    rows.forEach((row) => {
      const tr = document.createElement("tr");
      tr.innerHTML = `
        <td>${row.scenario_name}</td>
        <td>${row.parameter_display}</td>
        <td>${row.equipment_display}</td>
        <td>${row.capex_display}</td>
        <td>${row.opex_display}</td>
        <td>${row.production_display}</td>
        <td>${row.consumption_display}</td>
        <td>${row.maintenance_display}</td>
        <td>${row.iterations_display}</td>
        <td>${row.simulation_mean_display}</td>
      `;
      scenarioTableBody.appendChild(tr);
    });
    scenarioEmpty.hidden = rows.length > 0;
  };

  const renderOverallMetrics = () => {
    if (!overallMetricsList || !overallMetricsEmpty) {
      return;
    }
    overallMetricsList.innerHTML = "";
    const items = Array.isArray(state.overall_report_metrics)
      ? state.overall_report_metrics
      : [];
    items.forEach((item) => {
      const li = document.createElement("li");
      li.className = "metric-list-item";
      li.textContent = `${item.label}: ${item.value}`;
      overallMetricsList.appendChild(li);
    });
    overallMetricsEmpty.hidden = items.length > 0;
  };

  const renderRecentSimulations = () => {
    if (!recentList || !recentEmpty) {
      return;
    }
    recentList.innerHTML = "";
    const runs = Array.isArray(state.recent_simulations)
      ? state.recent_simulations
      : [];
    runs.forEach((run) => {
      const item = document.createElement("li");
      item.className = "metric-list-item";
      item.textContent = `${run.scenario_name} · ${run.iterations_display} iterations · ${run.mean_display}`;
      recentList.appendChild(item);
    });
    recentEmpty.hidden = runs.length > 0;
  };

  const renderMaintenanceReminders = () => {
    if (!maintenanceList || !maintenanceEmpty) {
      return;
    }
    maintenanceList.innerHTML = "";
    const items = Array.isArray(state.upcoming_maintenance)
      ? state.upcoming_maintenance
      : [];
    items.forEach((item) => {
      const li = document.createElement("li");
      li.innerHTML = `
        <span class="list-title">${item.equipment_name} · ${item.scenario_name}</span>
        <span class="list-detail">${item.date_display} · ${item.cost_display} · ${item.description}</span>
      `;
      maintenanceList.appendChild(li);
    });
    maintenanceEmpty.hidden = items.length > 0;
  };

  const buildChartConfig = (dataset, overrides = {}) => ({
    type: dataset.type || "bar",
    data: {
      labels: dataset.labels || [],
      datasets: dataset.datasets || [],
    },
    options: Object.assign(
      {
        responsive: true,
        maintainAspectRatio: false,
        plugins: {
          legend: { position: "top" },
          tooltip: { enabled: true },
        },
        scales: {
          x: { stacked: dataset.stacked ?? false },
          y: { stacked: dataset.stacked ?? false, beginAtZero: true },
        },
      },
      overrides.options || {}
    ),
  });

  const renderCharts = () => {
    if (costChartInstance) {
      costChartInstance.destroy();
    }
    if (activityChartInstance) {
      activityChartInstance.destroy();
    }

    const costData = state.scenario_cost_chart || {};
    const activityData = state.scenario_activity_chart || {};

    if (costChartCanvas && state.cost_chart_has_data) {
      costChartInstance = new Chart(
        costChartCanvas,
        buildChartConfig(costData, {
          options: {
            scales: {
              y: {
                beginAtZero: true,
                ticks: {
                  callback: (value) =>
                    typeof value === "number"
                      ? value.toLocaleString(undefined, {
                          maximumFractionDigits: 0,
                        })
                      : value,
                },
              },
            },
          },
        })
      );
      if (costChartEmpty) {
        costChartEmpty.hidden = true;
      }
      costChartCanvas.classList.remove("hidden");
    } else if (costChartEmpty && costChartCanvas) {
      costChartEmpty.hidden = false;
      costChartCanvas.classList.add("hidden");
    }

    if (activityChartCanvas && state.activity_chart_has_data) {
      activityChartInstance = new Chart(
        activityChartCanvas,
        buildChartConfig(activityData, {
          options: {
            scales: {
              y: {
                beginAtZero: true,
                ticks: {
                  callback: (value) =>
                    typeof value === "number"
                      ? value.toLocaleString(undefined, {
                          maximumFractionDigits: 0,
                        })
                      : value,
                },
              },
            },
          },
        })
      );
      if (activityChartEmpty) {
        activityChartEmpty.hidden = true;
      }
      activityChartCanvas.classList.remove("hidden");
    } else if (activityChartEmpty && activityChartCanvas) {
      activityChartEmpty.hidden = false;
      activityChartCanvas.classList.add("hidden");
    }
  };

  const renderView = () => {
    renderSummaryMetrics();
    renderScenarioTable();
    renderOverallMetrics();
    renderRecentSimulations();
    renderMaintenanceReminders();
    renderCharts();
  };

  const refreshDashboard = async () => {
    setStatus("Refreshing dashboard…", "success");
    if (refreshButton) {
      refreshButton.classList.add("is-loading");
    }

    try {
      const response = await fetch("/ui/dashboard/data", {
        headers: { "X-Requested-With": "XMLHttpRequest" },
      });

      if (!response.ok) {
        throw new Error("Unable to refresh dashboard data.");
      }

      const payload = await response.json();
      state = payload || {};
      renderView();
      setStatus("Dashboard updated.", "success");
    } catch (error) {
      console.error(error);
      setStatus(error.message || "Failed to refresh dashboard.", "error");
    } finally {
      if (refreshButton) {
        refreshButton.classList.remove("is-loading");
      }
    }
  };

  renderView();

  if (refreshButton) {
    refreshButton.addEventListener("click", refreshDashboard);
  }
})();