// server/services/scheduler.ts
import { randomUUID } from "node:crypto";
import { Cron } from "croner";
import { eq } from "drizzle-orm";
import { db, schema } from "../db/client.js";
import { listMachines } from "./machines.js";
import { refreshMachine } from "./refresh.js";
import { collectMetrics } from "./machineMetrics.js";
import { recordEvent } from "./machineState.js";

export type ScheduleAction = "apt_update_analyze" | "machine_metrics_simple" | "docker_scan";

export interface ScheduleScope {
  machineIds: "all" | string[];
}

export interface ScheduleView {
  id: string;
  name: string;
  enabled: boolean;
  cron: string;
  timezone: string | null;
  scope: ScheduleScope;
  actions: ScheduleAction[];
  concurrency: number;
  lastRunAt: string | null;
  lastStatus: string | null;
}

type ScheduleRow = typeof schema.schedules.$inferSelect;

function toView(r: ScheduleRow): ScheduleView {
  return {
    id: r.id,
    name: r.name,
    enabled: !!r.enabled,
    cron: r.cron,
    timezone: r.timezone,
    scope: JSON.parse(r.scopeJson) as ScheduleScope,
    actions: JSON.parse(r.actionsJson) as ScheduleAction[],
    concurrency: r.concurrency,
    lastRunAt: r.lastRunAt,
    lastStatus: r.lastStatus,
  };
}

// ---------------------------------------------------------------------------
// CRUD
// ---------------------------------------------------------------------------

export function listSchedules(): ScheduleView[] {
  return db.select().from(schema.schedules).all().map(toView);
}

export function getSchedule(id: string): ScheduleView | null {
  const r = db.select().from(schema.schedules).where(eq(schema.schedules.id, id)).get();
  return r ? toView(r) : null;
}

export interface ScheduleInput {
  name: string;
  cron: string;
  timezone?: string | null;
  enabled?: boolean;
  scope?: ScheduleScope;
  actions: ScheduleAction[];
  concurrency?: number;
}

export function createSchedule(input: ScheduleInput): ScheduleView {
  // Valide l'expression cron (lève si invalide), sans planifier.
  new Cron(input.cron).stop();
  const id = randomUUID();
  const now = new Date().toISOString();
  db.insert(schema.schedules).values({
    id,
    name: input.name,
    enabled: input.enabled === false ? 0 : 1,
    cron: input.cron,
    timezone: input.timezone ?? "Europe/Paris",
    scopeJson: JSON.stringify(input.scope ?? { machineIds: "all" }),
    actionsJson: JSON.stringify(input.actions),
    concurrency: input.concurrency ?? 2,
    createdAt: now,
    updatedAt: now,
  }).run();
  reloadSchedules();
  return getSchedule(id)!;
}

export function updateSchedule(id: string, input: Partial<ScheduleInput>): ScheduleView {
  const cur = db.select().from(schema.schedules).where(eq(schema.schedules.id, id)).get();
  if (!cur) throw new Error("Schedule introuvable");
  if (input.cron) new Cron(input.cron).stop(); // valide sans planifier
  db.update(schema.schedules).set({
    ...(input.name !== undefined ? { name: input.name } : {}),
    ...(input.enabled !== undefined ? { enabled: input.enabled ? 1 : 0 } : {}),
    ...(input.cron !== undefined ? { cron: input.cron } : {}),
    ...(input.timezone !== undefined ? { timezone: input.timezone } : {}),
    ...(input.scope !== undefined ? { scopeJson: JSON.stringify(input.scope) } : {}),
    ...(input.actions !== undefined ? { actionsJson: JSON.stringify(input.actions) } : {}),
    ...(input.concurrency !== undefined ? { concurrency: input.concurrency } : {}),
    updatedAt: new Date().toISOString(),
  }).where(eq(schema.schedules.id, id)).run();
  reloadSchedules();
  return getSchedule(id)!;
}

export function deleteSchedule(id: string): void {
  db.delete(schema.schedules).where(eq(schema.schedules.id, id)).run();
  reloadSchedules();
}

// ---------------------------------------------------------------------------
// Exécution
// ---------------------------------------------------------------------------

const locked = new Set<string>();

function resolveMachineIds(scope: ScheduleScope): string[] {
  const all = listMachines().map((m) => m.id);
  return scope.machineIds === "all" ? all : scope.machineIds.filter((id) => all.includes(id));
}

async function runActionOnMachine(machineId: string, action: ScheduleAction): Promise<void> {
  if (action === "apt_update_analyze") {
    await refreshMachine(machineId);
  } else if (action === "machine_metrics_simple") {
    await collectMetrics(machineId);
  } else if (action === "docker_scan") {
    const { scanDockerStacks } = await import("./dockerScan.js");
    await scanDockerStacks(machineId);
  }
}

/** Exécute un schedule : actions sur le périmètre, avec verrou par machine et concurrence. */
export async function runSchedule(id: string): Promise<{ ran: number; errors: number }> {
  const sched = getSchedule(id);
  if (!sched) throw new Error("Schedule introuvable");
  const machineIds = resolveMachineIds(sched.scope);
  let ran = 0;
  let errors = 0;

  const queue = [...machineIds];
  const worker = async () => {
    for (;;) {
      const machineId = queue.shift();
      if (!machineId) break;
      if (locked.has(machineId)) continue; // une action tourne déjà sur cette machine
      locked.add(machineId);
      try {
        for (const action of sched.actions) {
          await runActionOnMachine(machineId, action);
        }
        ran++;
      } catch (err) {
        errors++;
        recordEvent({
          machineId,
          eventType: "schedule_action_failed",
          severity: "warning",
          message: `Schedule « ${sched.name} » : ${(err as Error).message}`,
        });
      } finally {
        locked.delete(machineId);
      }
    }
  };

  const pool = Math.max(1, Math.min(sched.concurrency, machineIds.length || 1));
  await Promise.all(Array.from({ length: pool }, () => worker()));

  db.update(schema.schedules)
    .set({ lastRunAt: new Date().toISOString(), lastStatus: errors ? `partial (${errors} err)` : "ok" })
    .where(eq(schema.schedules.id, id))
    .run();
  return { ran, errors };
}

// ---------------------------------------------------------------------------
// Enregistrement croner
// ---------------------------------------------------------------------------

let jobs: Cron[] = [];

export function reloadSchedules(): void {
  for (const j of jobs) j.stop();
  jobs = [];
  for (const s of listSchedules()) {
    if (!s.enabled) continue;
    try {
      jobs.push(
        new Cron(s.cron, { timezone: s.timezone ?? undefined, name: s.id }, () => {
          runSchedule(s.id).catch((err) => console.error(`[scheduler] ${s.name}:`, (err as Error).message));
        }),
      );
    } catch (err) {
      console.error(`[scheduler] cron invalide pour ${s.name}:`, (err as Error).message);
    }
  }
}

export function stopSchedules(): void {
  for (const j of jobs) j.stop();
  jobs = [];
}