// server/services/machineMetrics.ts
import { eq } from "drizzle-orm";
import { db, schema } from "../db/client.js";
import { getMachineRow, getCreds } from "./machines.js";
import { renderTemplate } from "../templates/render.js";
import { runScriptSudo } from "../ssh/client.js";
import type { MachineMetricsSimple } from "@shared/types.js";

function section(raw: string, start: string, end?: string): string {
  const i = raw.indexOf(start);
  if (i < 0) return "";
  const from = i + start.length;
  const j = end ? raw.indexOf(end, from) : -1;
  return raw.slice(from, j < 0 ? undefined : j).trim();
}

const num = (s: string | undefined): number | null => {
  if (s === undefined) return null;
  const n = Number(s);
  return Number.isFinite(n) ? n : null;
};

export function parseMetrics(raw: string): MachineMetricsSimple {
  const cpuLines = section(raw, "===SU:METRICS_CPU===", "===SU:METRICS_MEM===").split("\n").filter(Boolean);
  const loadParts = (cpuLines[0] ?? "").trim().split(/\s+/);
  const cpu = {
    load1: num(loadParts[0]),
    load5: num(loadParts[1]),
    cores: num((cpuLines[1] ?? "").trim()),
  };

  const memBlock = section(raw, "===SU:METRICS_MEM===", "===SU:METRICS_FS===");
  const memKb = (key: string): number | null => {
    const m = new RegExp(`^${key}:\\s+(\\d+)\\s*kB`, "m").exec(memBlock);
    return m?.[1] ? Number(m[1]) * 1024 : null;
  };
  const totalBytes = memKb("MemTotal");
  const availableBytes = memKb("MemAvailable");
  const usedBytes = totalBytes !== null && availableBytes !== null ? totalBytes - availableBytes : null;
  const usedPercent = totalBytes && usedBytes !== null ? Math.round((usedBytes / totalBytes) * 100) : null;
  const memory = { totalBytes, usedBytes, availableBytes, usedPercent };

  const filesystems: MachineMetricsSimple["filesystems"] = [];
  for (const line of section(raw, "===SU:METRICS_FS===", "===SU:EXIT=").split("\n")) {
    if (!line.startsWith("FS\t")) continue;
    const [, mount, fstype, size, used, pcent] = line.split("\t");
    filesystems.push({
      mount: mount ?? "",
      fstype: fstype ?? "",
      sizeBytes: Number(size) || 0,
      usedBytes: Number(used) || 0,
      usedPercent: Number((pcent ?? "").replace("%", "")) || 0,
    });
  }

  const warnings: string[] = [];
  for (const fs of filesystems) {
    if (fs.usedPercent >= 90) warnings.push(`Disque ${fs.mount} à ${fs.usedPercent}%`);
  }
  if (usedPercent !== null && usedPercent >= 90) warnings.push(`Mémoire à ${usedPercent}%`);

  return { collectedAt: new Date().toISOString(), cpu, memory, filesystems, warnings };
}

/** Collecte les métriques d'une machine via SSH et persiste machine_metrics_latest. */
export async function collectMetrics(machineId: string): Promise<MachineMetricsSimple> {
  const m = getMachineRow(machineId);
  if (!m) throw new Error("Machine introuvable");
  const script = renderTemplate("apt/machine-metrics.sh.tpl", {});
  const res = await runScriptSudo(getCreds(m), script, () => {});
  const metrics = parseMetrics(res.stdout);

  const root = metrics.filesystems.find((f) => f.mount === "/");
  db.insert(schema.machineMetricsLatest)
    .values({
      machineId,
      collectedAt: metrics.collectedAt,
      cpuLoad1: metrics.cpu.load1,
      cpuLoad5: metrics.cpu.load5,
      cpuCores: metrics.cpu.cores,
      memoryTotalBytes: metrics.memory.totalBytes,
      memoryUsedBytes: metrics.memory.usedBytes,
      memoryAvailableBytes: metrics.memory.availableBytes,
      memoryUsedPercent: metrics.memory.usedPercent,
      filesystemsJson: JSON.stringify(metrics.filesystems),
      rootUsedPercent: root?.usedPercent ?? null,
      warningsJson: JSON.stringify(metrics.warnings),
    })
    .onConflictDoUpdate({
      target: schema.machineMetricsLatest.machineId,
      set: {
        collectedAt: metrics.collectedAt,
        cpuLoad1: metrics.cpu.load1,
        cpuLoad5: metrics.cpu.load5,
        cpuCores: metrics.cpu.cores,
        memoryTotalBytes: metrics.memory.totalBytes,
        memoryUsedBytes: metrics.memory.usedBytes,
        memoryAvailableBytes: metrics.memory.availableBytes,
        memoryUsedPercent: metrics.memory.usedPercent,
        filesystemsJson: JSON.stringify(metrics.filesystems),
        rootUsedPercent: root?.usedPercent ?? null,
        warningsJson: JSON.stringify(metrics.warnings),
      },
    })
    .run();

  return metrics;
}

/** Dernières métriques stockées (sans SSH), si présentes. */
export function getLatestMetrics(machineId: string): MachineMetricsSimple | null {
  const row = db.select().from(schema.machineMetricsLatest).where(eq(schema.machineMetricsLatest.machineId, machineId)).get();
  if (!row) return null;
  return {
    collectedAt: row.collectedAt,
    cpu: { load1: row.cpuLoad1, load5: row.cpuLoad5, cores: row.cpuCores },
    memory: {
      totalBytes: row.memoryTotalBytes,
      usedBytes: row.memoryUsedBytes,
      availableBytes: row.memoryAvailableBytes,
      usedPercent: row.memoryUsedPercent,
    },
    filesystems: row.filesystemsJson ? JSON.parse(row.filesystemsJson) : [],
    warnings: row.warningsJson ? JSON.parse(row.warningsJson) : [],
  };
}