// Electron main process for pon-fleet-upgrader.
//
// Responsibilities:
//   - Own the MCMS session (cookies stay out of the renderer).
//   - Expose IPC handlers that the renderer calls via window.api.*.
//   - Centralize TLS cert handling for self-signed internal MCMS installs.

const { app, BrowserWindow, ipcMain, dialog } = require('electron');
const path = require('path');
const fs = require('fs');
const {
  McmsClient, McmsApiError, extractOnuHealth,
  summarizeOltNniNetworks, planNniEdit,
} = require('./src/mcms-api');
const { summarizeDashboard } = require('./src/dashboard');
const { summarizeCpe } = require('./src/cpe');
const { lookupOui } = require('./src/oui');
const { summarizeOnuDetail } = require('./src/onudetail');
const { summarizeOltDetail } = require('./src/oltdetail');
const { planUpgrade, activeBankPtr, inactiveBank } = require('./src/bank-strategy');

/** @type {McmsClient | null} */
let client = null;
let mainWindow = null;

function createWindow() {
  mainWindow = new BrowserWindow({
    width: 1400,
    height: 900,
    title: 'PON Fleet Upgrader',
    webPreferences: {
      preload: path.join(__dirname, 'preload.js'),
      contextIsolation: true,
      nodeIntegration: false,
    },
  });
  mainWindow.loadFile(path.join(__dirname, 'renderer', 'index.html'));
}

app.whenReady().then(() => {
  createWindow();
  app.on('activate', () => {
    if (BrowserWindow.getAllWindows().length === 0) createWindow();
  });
});

app.on('window-all-closed', () => {
  if (process.platform !== 'darwin') app.quit();
});

// ---- IPC handlers ----------------------------------------------------

function requireClient() {
  if (!client) throw new Error('Not logged in — call api.login first.');
  return client;
}

// Format MCMS API errors for the renderer without leaking stack traces.
function toWireError(err) {
  if (err instanceof McmsApiError) {
    return { message: err.message, status: err.status, body: err.body };
  }
  return { message: err?.message || String(err) };
}

ipcMain.handle('api:login', async (_ev, { baseUrl, username, password, acceptSelfSigned }) => {
  try {
    client = new McmsClient({
      baseUrl,
      rejectUnauthorized: !acceptSelfSigned,
      // Verbose logging goes to the Electron terminal (npm start output).
      // Turn off by setting PON_FLEET_VERBOSE=0 in the env.
      verbose: process.env.PON_FLEET_VERBOSE !== '0',
    });
    const result = await client.login(username, password);
    return { ok: true, data: result };
  } catch (err) {
    client = null;
    return { ok: false, error: toWireError(err) };
  }
});

ipcMain.handle('api:logout', async () => {
  if (client) await client.logout();
  client = null;
  return { ok: true };
});

ipcMain.handle('api:listOnuConfigs', async (_ev, opts) => {
  try {
    const c = requireClient();
    // No projection and no query — MCMS's schema validator is picky about
    // projection paths that don't exist on every document version, and its
    // URL-param encoding of Mongo-style queries has been unreliable across
    // builds (spaces in field names, JSON escaping). We load the full fleet
    // (bounded by `limit`) and filter entirely client-side.
    const data = await c.listOnuConfigs({
      limit: opts?.limit,
      skip: opts?.skip,
    });
    return { ok: true, data };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Fast fleet load: configs + onu-states + olt-states. Tries the bulk
 * state endpoint first; if that fails, the renderer can follow up with
 * api:fetchStates to fetch states per-ONU. OLT-STATE carries the
 * registration bucket (Registered / Deregistered / Dying Gasp / etc.)
 * per ONU — see 323-1961-306 Procedure 2 — so we load it here and tag
 * each merged ONU with its `_status.status`.
 */
ipcMain.handle('api:listFleet', async (_ev) => {
  try {
    const c = requireClient();
    const configs = await c.listAllOnuConfigs();
    let states = [];
    let statesError = null;
    try {
      states = await c.listAllOnuStates();
    } catch (e) {
      statesError = toWireError(e);
    }
    // OLT-STATE fetch is best-effort. If it fails the UI falls back to
    // "unknown" status and the down-duration filter is simply unavailable.
    let oltStates = [];
    let oltStatesError = null;
    try {
      oltStates = await c.listAllOltStates();
    } catch (e) {
      oltStatesError = toWireError(e);
    }
    // Build onuId -> { status, oltMac } from OLT-STATE["ONU States"].
    // An ONU should appear in exactly one bucket on exactly one OLT; in
    // the rare case of duplicates we prefer a non-"Registered" bucket
    // since that's the interesting signal (the newer OLT wins otherwise).
    const statusByOnu = new Map();
    for (const olt of oltStates) {
      const buckets = olt?.['ONU States'] || {};
      const oltMac = olt?._id;
      for (const [bucket, ids] of Object.entries(buckets)) {
        if (!Array.isArray(ids)) continue;
        for (const id of ids) {
          const existing = statusByOnu.get(id);
          if (!existing || existing.status === 'Registered') {
            statusByOnu.set(id, { status: bucket, oltMac });
          }
        }
      }
    }
    const stateById = new Map(states.map((s) => [s._id, s]));
    const merged = configs.map((cfg) => ({
      ...cfg,
      _state: stateById.get(cfg._id) || null,
      _status: statusByOnu.get(cfg._id) || null,
    }));
    return {
      ok: true,
      data: merged,
      meta: {
        configCount: configs.length,
        stateCount: states.length,
        oltStateCount: oltStates.length,
        statesError,    // null on success, error object on failure
        oltStatesError, // same, for OLT-STATE fetch
      },
    };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Phase 2: fetch ONU-STATE per-ONU with bounded concurrency. The web
 * UI on this MCMS build hits /v3/onus/states/<id>/ individually rather
 * than the bulk list endpoint, which matches what we do here. Progress
 * events stream back on 'states:progress' so the UI can fill in the
 * Equipment ID column as results arrive.
 */
ipcMain.handle('api:fetchStates', async (event, { onuIds, concurrency = 20 }) => {
  try {
    const c = requireClient();
    const queue = [...onuIds];
    const results = [];
    let done = 0;
    const total = onuIds.length;

    async function worker() {
      for (;;) {
        const id = queue.shift();
        if (id === undefined) return;
        let state = null;
        try {
          state = await c.getOnuState(id);
        } catch (e) {
          // Per-ONU failure is non-fatal; the UI will just show a blank
          // Equipment ID for this row.
          state = null;
        }
        results.push({ onuId: id, state });
        done += 1;
        event.sender.send('states:progress', { onuId: id, state, done, total });
      }
    }

    const workers = Array.from({ length: Math.min(concurrency, total) }, () => worker());
    await Promise.all(workers);
    return { ok: true, data: results };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

ipcMain.handle('api:getOnuConfig', async (_ev, { onuId }) => {
  try {
    const c = requireClient();
    const data = await c.getOnuConfig(onuId);
    return { ok: true, data };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * CPE (customer router) behind an ONU, for the ONU info page: DHCPv4/v6
 * lease state + renewal health, plus the CPE MAC's vendor (OUI lookup,
 * cached ~1 month). Returns null when there's no CPE record.
 */
ipcMain.handle('api:getOnuCpe', async (_ev, { onuId }) => {
  try {
    const c = requireClient();
    const doc = await c.getCpe(onuId);
    const cpe = summarizeCpe(doc);
    if (cpe) cpe.cpeVendor = await lookupOui(cpe.cpeMac);
    return { ok: true, data: cpe };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Rich per-ONU detail for the info page: firmware banks, UNI-ETH ports +
 * last Ethernet LOS, alarms, parent OLT, upstream switch (LLDP), a traffic
 * time-series, and the CPE summary — one round of fetches summarized via
 * src/onudetail.js + src/cpe.js.
 */
ipcMain.handle('api:getOnuDetail', async (_ev, { onuId, windowMin = 60 }) => {
  try {
    const c = requireClient();
    const [cfg, alarmsDoc, statsSeries] = await Promise.all([
      c.getOnuConfig(onuId).catch(() => null),
      c.getOnuAlarms(onuId).catch(() => null),
      c.getOnuStatsSeries(onuId, { minutes: windowMin }).catch(() => []),
    ]);
    const oltMac = alarmsDoc?.OLT?.['MAC Address'];
    const oltCfg = oltMac ? await c.getOltConfig(oltMac).catch(() => null) : null;
    const detail = summarizeOnuDetail({ cfg, alarmsDoc, statsSeries, oltCfg, windowMin });
    const cpeDoc = await c.getCpe(onuId).catch(() => null);
    detail.cpe = summarizeCpe(cpeDoc);
    if (detail.cpe) detail.cpe.cpeVendor = await lookupOui(detail.cpe.cpeMac);
    return { ok: true, data: detail };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Rich OLT detail (clicked from an ONU's Parent OLT card): identity +
 * traffic + temperature + ONU counts + laser + alarms + upstream switch.
 */
ipcMain.handle('api:getOltDetail', async (_ev, { oltMac }) => {
  try {
    const c = requireClient();
    const [oltCfg, oltState, alarmsDoc] = await Promise.all([
      c.getOltConfig(oltMac).catch(() => null),
      c.getOltState(oltMac).catch(() => null),
      c.getOltAlarms(oltMac).catch(() => null),
    ]);
    return { ok: true, data: summarizeOltDetail({ oltCfg, oltState, alarmsDoc }) };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

ipcMain.handle('api:listOnuFirmware', async () => {
  try {
    const c = requireClient();
    const data = await c.listOnuFirmware();
    return { ok: true, data };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

ipcMain.handle('api:uploadFirmware', async () => {
  try {
    const c = requireClient();
    const picked = await dialog.showOpenDialog(mainWindow, {
      title: 'Select ONU firmware (.bin)',
      filters: [{ name: 'Firmware', extensions: ['bin'] }],
      properties: ['openFile'],
    });
    if (picked.canceled || picked.filePaths.length === 0) {
      return { ok: false, error: { message: 'cancelled' } };
    }
    const filePath = picked.filePaths[0];
    const buf = fs.readFileSync(filePath);
    const filename = path.basename(filePath);
    const base64 = buf.toString('base64');
    // Infer version from filename (e.g. Interos-Everest-5.12.0-R-EV05120R.bin
    // -> version "EV05120R"). Users can fix this up later if wrong.
    const versionMatch = filename.match(/([A-Z]{2}\d{5}[A-Z]?)/);
    const metadata = {
      'Compatible Manufacturer': 'TIBITCOM',
      'Compatible Model': ['MicroPlug ONU'],
      Version: versionMatch ? versionMatch[1] : '',
    };
    const body = await c.uploadOnuFirmware(filename, base64, metadata);
    return { ok: true, data: { filename, metadata, body } };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Dry-run planner: given a set of ONUs and a target firmware, return the
 * planned write-slot + before/after for each ONU *without* mutating anything.
 */
ipcMain.handle('api:planUpgrade', async (_ev, { onuIds, targetFile, targetVersion }) => {
  try {
    const c = requireClient();
    const plans = [];
    for (const onuId of onuIds) {
      const cfg = await c.getOnuConfig(onuId);
      if (!cfg) {
        plans.push({ onuId, error: 'ONU config not found' });
        continue;
      }
      const plan = planUpgrade(cfg, { targetFile, targetVersion });
      plans.push({
        onuId,
        name: cfg?.ONU?.Name || '',
        address: cfg?.ONU?.Address || '',
        ponMode: cfg?.ONU?.['PON Mode'] || '',
        ...plan.summary,
        writeSlot: plan.writeSlot,
      });
    }
    return { ok: true, data: plans };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Per-ONU execution (Procedure 7) — iterates, fetches the doc, mutates the
 * FW bank fields, PUTs the full document back. This is the "one-at-a-time,
 * see errors live" path.
 */
ipcMain.handle('api:executePerOnu', async (event, { onuIds, targetFile, targetVersion }) => {
  try {
    const c = requireClient();
    const results = [];
    for (let i = 0; i < onuIds.length; i++) {
      const onuId = onuIds[i];
      // Fire per-ONU progress back to the renderer.
      event.sender.send('upgrade:progress', {
        index: i,
        total: onuIds.length,
        onuId,
        phase: 'fetching',
      });
      try {
        const cfg = await c.getOnuConfig(onuId);
        if (!cfg) throw new Error('ONU config not found');

        const plan = planUpgrade(cfg, { targetFile, targetVersion });
        // Apply the mutation in place on the fetched document so we PUT the
        // full doc back (MCMS uses PUT = replace, not partial).
        const mutated = { ...cfg, ONU: { ...cfg.ONU, ...plan.fwFields } };

        event.sender.send('upgrade:progress', {
          index: i,
          total: onuIds.length,
          onuId,
          phase: 'writing',
          writeSlot: plan.writeSlot,
        });
        await c.putOnuConfig(onuId, mutated);
        results.push({ onuId, ok: true, writeSlot: plan.writeSlot });
      } catch (err) {
        results.push({ onuId, ok: false, error: toWireError(err) });
      }
    }
    return { ok: true, data: results };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Bulk execution (Procedure 8) — single AUTO-TASK-CFG that MCMS schedules
 * across all selected serials. Recommended path for large fleets.
 */
ipcMain.handle('api:executeBulkTask', async (_ev, opts) => {
  try {
    const c = requireClient();
    const body = await c.createFirmwareTask(opts);
    return { ok: true, data: body };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

ipcMain.handle('api:getTaskConfig', async (_ev, { taskId }) => {
  try {
    const c = requireClient();
    const data = await c.getTaskConfig(taskId);
    return { ok: true, data };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

ipcMain.handle('api:getUpgradeStatus', async (_ev, { onuId }) => {
  try {
    const c = requireClient();
    const data = await c.getOnuUpgradeStatus(onuId);
    return { ok: true, data };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Pre-flight link-health check. For each selected ONU, re-fetch the
 * ONU-STATE document (so the snapshot is fresh at decision time, not
 * stale from the original fleet load) and reduce it to a single
 * health flag (ok / pre / post / buggy / nodata / error) plus the
 * raw FEC counters and optical levels.
 *
 * Source fields (observed on MCMS 6.2 + Interos Everest 5.x ONUs):
 *   STATE.STATS["ONU-PON"]["RX Pre-FEC BER" | "RX Post-FEC BER"
 *                          | "RX Optical Level" | "TX Optical Level"]
 *   STATE.STATS["OLT-PON"]["RX Pre-FEC BER" | "RX Post-FEC BER"]
 *
 * Streams progress on 'fec:progress' as each ONU resolves so the
 * preview table can paint its pill the moment its result lands.
 */
ipcMain.handle('api:fetchFecHealth', async (event, { onuIds, concurrency = 8 }) => {
  try {
    const c = requireClient();
    const queue = [...onuIds];
    const results = [];
    let done = 0;
    const total = onuIds.length;

    async function worker() {
      for (;;) {
        const id = queue.shift();
        if (id === undefined) return;
        let entry = { onuId: id, flag: 'nodata' };
        try {
          const stateDoc = await c.getOnuState(id);
          const health = extractOnuHealth(stateDoc);
          entry = {
            onuId: id,
            flag: health.flag,
            detail: health.detail || '',
            counters: health.counters || [],
            optical: health.optical || {},
            sampleTime: stateDoc?.Time || '',
          };
        } catch (e) {
          entry = { onuId: id, flag: 'error', error: toWireError(e) };
        }
        results.push(entry);
        done += 1;
        event.sender.send('fec:progress', { ...entry, done, total });
      }
    }

    const workers = Array.from({ length: Math.min(concurrency, total) }, () => worker());
    await Promise.all(workers);
    return { ok: true, data: results };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Internal CSV writer used by both the plan-save (on Execute) and the
 * verify-save (after a comparison run). Always quotes every cell —
 * MCMS values are full of CSV-hostile characters (commas in addresses,
 * embedded quotes in operator-entered names, occasional newlines).
 * Always prepends a UTF-8 BOM so Excel auto-detects the encoding and
 * Norwegian Æ/Ø/Å survive on Windows.
 */
function writeCsvFile({ prefix, filenameHint, headers, rows }) {
  const downloadsDir = app.getPath('downloads');
  const ts = new Date();
  const pad = (n) => String(n).padStart(2, '0');
  const stamp =
    `${ts.getFullYear()}${pad(ts.getMonth() + 1)}${pad(ts.getDate())}` +
    `-${pad(ts.getHours())}${pad(ts.getMinutes())}${pad(ts.getSeconds())}`;
  const safeHint = (filenameHint || 'csv')
    .toString()
    .replace(/[^A-Za-z0-9._-]+/g, '_')
    .slice(0, 60);
  const filename = `${prefix}-${safeHint}-${stamp}.csv`;
  const fullPath = path.join(downloadsDir, filename);

  const csvCell = (v) => {
    if (v === null || v === undefined) return '';
    const s = typeof v === 'string' ? v : String(v);
    return '"' + s.replace(/"/g, '""') + '"';
  };
  const csvRow = (cells) => cells.map(csvCell).join(',');
  const lines = [csvRow(headers)];
  for (const row of rows) lines.push(csvRow(headers.map((h) => row[h])));
  const body = '' + lines.join('\r\n') + '\r\n';
  fs.writeFileSync(fullPath, body, { encoding: 'utf8' });
  return { path: fullPath, filename, rowCount: rows.length };
}

/**
 * Save an upgrade plan to a timestamped CSV in the user's Downloads
 * folder. Called automatically by the renderer the moment the operator
 * clicks Execute, so there's always a paper trail of what got
 * scheduled — even if the MCMS write later fails.
 */
ipcMain.handle('api:savePlanCsv', async (_ev, { rows, filenameHint, headers }) => {
  try {
    if (!Array.isArray(rows) || !Array.isArray(headers)) {
      throw new Error('rows and headers are required arrays');
    }
    const data = writeCsvFile({
      prefix: 'pon-upgrade', filenameHint, headers, rows,
    });
    return { ok: true, data };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Generic CSV save. Used by the verify flow with prefix='pon-verify'.
 * Same writeCsvFile semantics as the plan save.
 */
ipcMain.handle('api:saveCsvFile', async (_ev, { rows, filenameHint, headers, prefix = 'pon-csv' }) => {
  try {
    if (!Array.isArray(rows) || !Array.isArray(headers)) {
      throw new Error('rows and headers are required arrays');
    }
    const safePrefix = String(prefix).replace(/[^A-Za-z0-9._-]+/g, '_').slice(0, 40) || 'pon-csv';
    const data = writeCsvFile({ prefix: safePrefix, filenameHint, headers, rows });
    return { ok: true, data };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Open an existing CSV from disk (default: Downloads). Returns the raw
 * text so the renderer can parse it with its own CSV parser. We don't
 * parse here because the renderer already needs to know the column
 * layout to build comparisons.
 */
ipcMain.handle('api:openCsvFile', async () => {
  try {
    const picked = await dialog.showOpenDialog(mainWindow, {
      title: 'Open upgrade plan CSV',
      defaultPath: app.getPath('downloads'),
      filters: [{ name: 'CSV', extensions: ['csv'] }],
      properties: ['openFile'],
    });
    if (picked.canceled || !picked.filePaths.length) {
      return { ok: false, error: { message: 'cancelled' } };
    }
    const filePath = picked.filePaths[0];
    const text = fs.readFileSync(filePath, 'utf8');
    return { ok: true, data: { path: filePath, text } };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Per-ONU snapshot fetch for the verify flow: pulls BOTH the ONU-STATE
 * (for current FEC counters and optical levels) AND the ONU-CFG (so we
 * can verify the active firmware version actually flipped to the
 * target). Streams progress on 'verify:progress' so the table can
 * update incrementally on big lists.
 */
ipcMain.handle('api:fetchOnuSnapshot', async (event, { onuIds, concurrency = 8 }) => {
  try {
    const c = requireClient();
    const queue = [...onuIds];
    const results = [];
    let done = 0;
    const total = onuIds.length;

    async function worker() {
      for (;;) {
        const id = queue.shift();
        if (id === undefined) return;
        let entry = { onuId: id };
        try {
          const [stateDoc, cfgDoc] = await Promise.all([
            c.getOnuState(id).catch(() => null),
            c.getOnuConfig(id).catch(() => null),
          ]);
          const health = extractOnuHealth(stateDoc);
          entry = {
            onuId: id,
            flag: health.flag,
            counters: health.counters || [],
            optical: health.optical || {},
            sampleTime: stateDoc?.Time || '',
            cfg: cfgDoc,
          };
        } catch (e) {
          entry = { onuId: id, flag: 'error', error: toWireError(e) };
        }
        results.push(entry);
        done += 1;
        event.sender.send('verify:progress', { onuId: id, done, total, flag: entry.flag });
      }
    }

    const workers = Array.from({ length: Math.min(concurrency, total) }, () => worker());
    await Promise.all(workers);
    return { ok: true, data: results };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Bulk delete ONUs from MCMS. For each ONU we delete the CFG document
 * (Procedure 43 in the PON Manager User Guide), then best-effort delete
 * the STATE document so stale Equipment-ID/registration entries don't
 * hang around. STATE deletion failures are ignored — the OLT will
 * rewrite it on next registration anyway, but CFG deletion is the
 * authoritative action.
 *
 * Progress streams back on 'delete:progress' so the renderer can tick
 * through a large selection without locking up. Concurrency is kept low
 * (default 5) because DELETE is more disruptive than GET and we don't
 * want to stampede the MCMS backend.
 */
ipcMain.handle('api:deleteOnus', async (event, { onuIds, concurrency = 5 }) => {
  try {
    const c = requireClient();
    const queue = [...onuIds];
    const results = [];
    let done = 0;
    const total = onuIds.length;

    async function worker() {
      for (;;) {
        const id = queue.shift();
        if (id === undefined) return;
        let ok = false;
        let error = null;
        try {
          await c.deleteOnuConfig(id);
          ok = true;
          // State deletion is best-effort and does not affect `ok`.
          try { await c.deleteOnuState(id); } catch (_) { /* ignore */ }
        } catch (e) {
          error = toWireError(e);
        }
        results.push({ onuId: id, ok, error });
        done += 1;
        event.sender.send('delete:progress', { onuId: id, ok, error, done, total });
      }
    }

    const workers = Array.from({ length: Math.min(concurrency, total) }, () => worker());
    await Promise.all(workers);
    return { ok: true, data: results };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

// ---- OLT PON flooding mode -------------------------------------------

/**
 * Bulk-load every OLT-CFG, summarize each one's NNI Networks against
 * the given TAG MATCH pattern, and return a flat row per OLT.
 */
ipcMain.handle('api:listOlts', async (_ev, opts) => {
  try {
    const c = requireClient();
    const tagPattern = (opts && opts.tagPattern) || '';
    const cfgs = await c.listAllOltConfigs();
    const rows = cfgs.map((cfg) => {
      const summary = summarizeOltNniNetworks(cfg, tagPattern);
      const counts = { private: 0, auto: 0, unknown: 0 };
      for (const s of summary) counts[s.mode] = (counts[s.mode] || 0) + 1;
      return {
        _id: cfg._id,
        name: cfg?.OLT?.Name || '',
        location: cfg?.OLT?.Location || '',
        ponMode: cfg?.OLT?.['PON Mode'] || '',
        activeFwVersion: cfg?.OLT?.['FW Bank Versions']?.[cfg?.OLT?.['FW Bank Ptr']] || '',
        matchingNni: summary,
        counts,
      };
    });
    return { ok: true, data: rows };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

/**
 * Apply a set of NNI-service edits (flood mode and/or DHCPv4/DHCPv6 filter)
 * to a list of OLT IDs. For each OLT we GET the current CFG (to avoid
 * stomping concurrent edits), run planNniEdit, and PUT the result back.
 * Streams progress. (Channel name kept as executeFloodChange for wire
 * compatibility.)
 *
 * Concurrency is kept low (default 3) — OLT writes carry a much larger
 * blast radius than ONU reads, so we deliberately stay below the ONU
 * delete (5) and state-fetch (8) limits.
 */
ipcMain.handle('api:executeFloodChange', async (event, opts) => {
  try {
    const c = requireClient();
    const {
      oltIds, tagPattern, flood = null, dhcpv4 = null, dhcpv6 = null,
      concurrency = 3,
    } = opts || {};
    const queue = [...oltIds];
    const results = [];
    let done = 0;
    const total = oltIds.length;

    async function worker() {
      for (;;) {
        const id = queue.shift();
        if (id === undefined) return;
        let entry = { oltId: id, ok: false };
        try {
          const cfg = await c.getOltConfig(id);
          if (!cfg) throw new Error('OLT not found');
          const plan = planNniEdit(cfg, { tagPattern, flood, dhcpv4, dhcpv6 });
          if (plan.changes.length === 0) {
            entry = { oltId: id, ok: true, noop: true, changes: [], skipped: plan.unchanged };
          } else {
            await c.putOltConfig(id, plan.newDoc);
            entry = { oltId: id, ok: true, changes: plan.changes, skipped: plan.unchanged };
          }
        } catch (e) {
          entry = { oltId: id, ok: false, error: toWireError(e) };
        }
        results.push(entry);
        done += 1;
        event.sender.send('olt-flood:progress', { ...entry, done, total });
      }
    }
    const workers = Array.from({ length: Math.min(concurrency, total) }, () => worker());
    await Promise.all(workers);
    return { ok: true, data: results };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});

// ---- Dashboard telemetry --------------------------------------------

/**
 * Network-wide telemetry for the Dashboard tab. Aggregation lives in the
 * shared, pure src/dashboard.js (so the web server computes identically);
 * this handler just fetches the inputs. Light by default (small OLT-STATE
 * docs); the per-ONU optical/FEC scan runs only when `extraStats` is set.
 */
ipcMain.handle('api:dashboardStats', async (_ev, opts) => {
  try {
    const c = requireClient();
    const extraStats = !!(opts && opts.extraStats);
    const olts = await c.listAllOltStates();
    const onuStates = extraStats ? await c.listAllOnuStates() : null;
    let controllerCount = null;
    try { controllerCount = (await c.listAllControllerConfigs()).length; } catch (_) { /* best-effort */ }
    return { ok: true, data: summarizeDashboard({ olts, onuStates, controllerCount }) };
  } catch (err) {
    return { ok: false, error: toWireError(err) };
  }
});