// app.js — page globale : KPIs, graphique mensuel AWS/Azure (cliquable,
// multi-sélection), table des tenants.

let allTenants = [];
let currentMonths = [];
let currentProvidersTotals = { aws: [], azure: [] };
let monthlyChart = null;
const selectedMonths = new Set();

async function loadOverview() {
  const res = await fetch("/api/overview?months=12");
  if (!res.ok) throw new Error(`API overview: HTTP ${res.status}`);
  return res.json();
}

function renderKpis(data) {
  document.getElementById("kpi-total").textContent = formatEUR(data.kpis.total_current_month);
  document.getElementById("kpi-aws").textContent = formatEUR(data.kpis.total_aws_current_month);
  document.getElementById("kpi-azure").textContent = formatEUR(data.kpis.total_azure_current_month);

  const errorCount = data.kpis.tenants_error.length;
  const errEl = document.getElementById("kpi-errors");
  errEl.textContent = String(errorCount);
  errEl.style.color = errorCount > 0 ? "var(--status-critical)" : "";

  const banner = document.getElementById("error-banner");
  if (errorCount > 0) {
    const names = data.kpis.tenants_error
      .map((t) => `${providerLabel(t.provider)} / ${escapeHtml(t.name)}`)
      .join(", ");
    banner.innerHTML = `
      <div class="banner error">
        <div>
          <strong>${errorCount} tenant${errorCount > 1 ? "s" : ""} en échec de collecte</strong> :
          ${names}. Voir la table ci-dessous ou <code>cron.log</code> pour le détail.
        </div>
      </div>`;
  } else {
    banner.innerHTML = "";
  }
}

function dimmed(hex) {
  return Chart.helpers.color(hex).alpha(0.3).rgbString();
}

function renderMonthlyChart() {
  const labels = currentMonths.map(monthLabel);
  const surface = cssVar("--surface-1");
  const awsColor = cssVar("--provider-aws");
  const azureColor = cssVar("--provider-azure");

  const colorFor = (base) => (ctx) => {
    if (selectedMonths.size === 0) return base;
    return selectedMonths.has(currentMonths[ctx.dataIndex]) ? base : dimmed(base);
  };

  if (monthlyChart) {
    monthlyChart.destroy();
    monthlyChart = null;
  }

  const ctx = document.getElementById("monthly-chart").getContext("2d");
  monthlyChart = new Chart(ctx, {
    type: "bar",
    data: {
      labels,
      datasets: [
        {
          label: "AWS",
          data: currentProvidersTotals.aws,
          backgroundColor: colorFor(awsColor),
          borderColor: surface,
          borderWidth: { top: 2, right: 0, bottom: 0, left: 0 },
          borderSkipped: false,
          borderRadius: { topLeft: 4, topRight: 4 },
          stack: "total",
          maxBarThickness: 24,
        },
        {
          label: "Azure",
          data: currentProvidersTotals.azure,
          backgroundColor: colorFor(azureColor),
          borderColor: surface,
          borderWidth: { top: 2, right: 0, bottom: 0, left: 0 },
          borderSkipped: false,
          stack: "total",
          maxBarThickness: 24,
        },
      ],
    },
    options: {
      ...chartBaseOptions(),
      onHover: (evt, elements) => {
        evt.native.target.style.cursor = elements.length ? "pointer" : "default";
      },
      onClick: (evt, elements) => {
        if (!elements.length) return;
        const monthKey = currentMonths[elements[0].index];
        if (selectedMonths.has(monthKey)) {
          selectedMonths.delete(monthKey);
        } else {
          selectedMonths.add(monthKey);
        }
        // Ne pas détruire ce chart depuis son propre handler onClick — Chart.js
        // est encore en train de dispatcher l'événement. On reporte au tick
        // suivant pour éviter de corrompre ses listeners internes.
        setTimeout(() => {
          renderMonthlyChart();
          renderTenantsTable(filteredTenants());
        }, 0);
      },
      plugins: {
        ...chartBaseOptions().plugins,
        tooltip: {
          ...chartBaseOptions().plugins.tooltip,
          callbacks: {
            label: (item) => `${item.dataset.label} : ${formatEUR(item.parsed.y)}`,
          },
        },
      },
      scales: {
        x: { ...chartBaseOptions().scales.x, stacked: true },
        y: { ...chartBaseOptions().scales.y, stacked: true },
      },
    },
  });
}

function statusInfo(tenant) {
  if (tenant.status === "ok") return { cls: "ok", label: "OK" };
  if (tenant.status === "error") return { cls: "error", label: "Erreur" };
  return { cls: "unknown", label: "Pas encore collecté" };
}

function selectedMonthIndexes() {
  return currentMonths
    .map((mk, i) => (selectedMonths.has(mk) ? i : -1))
    .filter((i) => i >= 0);
}

function renderSelectionNote() {
  const el = document.getElementById("month-selection-note");
  if (selectedMonths.size === 0) {
    el.innerHTML = "";
    return;
  }
  const labels = currentMonths.filter((mk) => selectedMonths.has(mk)).map(monthLabel).join(", ");
  el.innerHTML = `
    <span>Sélection : ${labels}</span>
    <button type="button" id="clear-selection">Réinitialiser</button>`;
  document.getElementById("clear-selection").addEventListener("click", () => {
    selectedMonths.clear();
    renderMonthlyChart();
    renderSelectionNote();
    renderTenantsTable(filteredTenants());
  });
}

function renderTenantsTable(tenants) {
  const wrap = document.getElementById("tenants-table-wrap");
  renderSelectionNote();

  if (tenants.length === 0) {
    wrap.innerHTML = `<div class="empty-state">Aucun tenant collecté pour l'instant. Lance <code>collect.py</code> ou <code>import_historical.py</code> pour peupler le dashboard.</div>`;
    return;
  }

  const indexes = selectedMonthIndexes();
  const selectionMode = indexes.length > 0;

  const rows = tenants
    .map((t) => {
      const st = statusInfo(t);

      if (selectionMode) {
        const amount = indexes.reduce((sum, i) => sum + (t.monthly[i] || 0), 0);
        return `
          <tr class="clickable" data-provider="${t.provider}" data-name="${escapeHtml(t.name)}">
            <td>
              <span class="name-cell">
                <span class="provider-badge ${t.provider}">${providerLabel(t.provider)}</span>
                ${escapeHtml(t.name)}
              </span>
            </td>
            <td class="num">${formatEUR(amount)}</td>
            <td>
              <span class="status-label">
                <span class="status-dot ${st.cls}"></span>${st.label}
              </span>
            </td>
          </tr>`;
      }

      const delta = formatPct(t.delta_pct);
      return `
        <tr class="clickable" data-provider="${t.provider}" data-name="${escapeHtml(t.name)}">
          <td>
            <span class="name-cell">
              <span class="provider-badge ${t.provider}">${providerLabel(t.provider)}</span>
              ${escapeHtml(t.name)}
            </span>
          </td>
          <td class="num">${formatEUR(t.current_month)}</td>
          <td class="num">${formatEUR(t.previous_month)}</td>
          <td class="num kpi-delta ${deltaClass(t.delta_pct)}" style="justify-content:flex-end; display:flex;">
            ${delta ? `${deltaArrow(t.delta_pct)} ${delta}` : "—"}
          </td>
          <td>
            <span class="status-label">
              <span class="status-dot ${st.cls}"></span>${st.label}
            </span>
          </td>
        </tr>`;
    })
    .join("");

  const header = selectionMode
    ? `<tr><th>Tenant</th><th class="num">Montant (sélection)</th><th>Statut collecte</th></tr>`
    : `<tr>
         <th>Tenant</th>
         <th class="num">Mois en cours</th>
         <th class="num">Mois précédent</th>
         <th class="num">Évolution</th>
         <th>Statut collecte</th>
       </tr>`;

  wrap.innerHTML = `
    <table class="data-table">
      <thead>${header}</thead>
      <tbody>${rows}</tbody>
    </table>`;

  wrap.querySelectorAll("tr.clickable").forEach((tr) => {
    tr.addEventListener("click", () => {
      window.location.href = `/tenant/${tr.dataset.provider}/${encodeURIComponent(tr.dataset.name)}`;
    });
  });
}

function filteredTenants() {
  const q = document.getElementById("tenant-search").value.trim().toLowerCase();
  if (!q) return allTenants;
  return allTenants.filter((t) => t.name.toLowerCase().includes(q));
}

function setupSearch() {
  document.getElementById("tenant-search").addEventListener("input", () => {
    renderTenantsTable(filteredTenants());
  });
}

async function init() {
  try {
    const data = await loadOverview();
    allTenants = data.tenants;
    currentMonths = data.months;
    currentProvidersTotals = data.providers_totals;
    renderKpis(data);
    renderMonthlyChart();
    renderTenantsTable(allTenants);
    setupSearch();
  } catch (e) {
    document.getElementById("error-banner").innerHTML = `
      <div class="banner error"><strong>Erreur de chargement du dashboard</strong> : ${escapeHtml(e.message)}</div>`;
    document.getElementById("tenants-table-wrap").innerHTML = "";
  }
}

init();