import {
  AlertChannel,
  HealthCheckTargetType,
  HealthCheckType,
  MonitoringAlertStatus,
  Severity
} from "@prisma/client";
import { Router } from "express";
import { z } from "zod";
import { HttpError } from "../lib/http-error";
import { prisma } from "../lib/prisma";
import { toPrismaJsonValue } from "../lib/prisma-json";
import { authorize, isTenantScopedUser, requireAuth } from "../middleware/auth";
import { logAudit } from "../services/audit.service";
import {
  clusterResourceForecast,
  createAlertRule,
  createHealthCheckDefinition,
  evaluateAlertRulesNow,
  faultyDeploymentInsights,
  listAlertEvents,
  listAlertNotifications,
  listAlertRules,
  listHealthCheckResults,
  listHealthChecks,
  monitoringOverview,
  runHealthCheckNow,
  updateAlertRule,
  updateHealthCheckDefinition
} from "../services/monitoring.service";

const router = Router();

const healthCheckSchema = z.object({
  name: z.string().min(2),
  description: z.string().optional(),
  target_type: z.nativeEnum(HealthCheckTargetType),
  check_type: z.nativeEnum(HealthCheckType).optional(),
  tenant_id: z.string().optional(),
  vm_id: z.string().optional(),
  node_id: z.string().optional(),
  cpu_warn_pct: z.number().min(0).max(100).optional(),
  cpu_critical_pct: z.number().min(0).max(100).optional(),
  ram_warn_pct: z.number().min(0).max(100).optional(),
  ram_critical_pct: z.number().min(0).max(100).optional(),
  disk_warn_pct: z.number().min(0).max(100).optional(),
  disk_critical_pct: z.number().min(0).max(100).optional(),
  disk_io_read_warn: z.number().min(0).optional(),
  disk_io_read_critical: z.number().min(0).optional(),
  disk_io_write_warn: z.number().min(0).optional(),
  disk_io_write_critical: z.number().min(0).optional(),
  network_in_warn: z.number().min(0).optional(),
  network_in_critical: z.number().min(0).optional(),
  network_out_warn: z.number().min(0).optional(),
  network_out_critical: z.number().min(0).optional(),
  latency_warn_ms: z.number().int().min(1).optional(),
  latency_critical_ms: z.number().int().min(1).optional(),
  schedule_minutes: z.number().int().min(1).max(1440).optional(),
  enabled: z.boolean().optional(),
  metadata: z.record(z.unknown()).optional()
});

const alertRuleSchema = z.object({
  name: z.string().min(2),
  description: z.string().optional(),
  tenant_id: z.string().optional(),
  vm_id: z.string().optional(),
  node_id: z.string().optional(),
  cpu_threshold_pct: z.number().min(0).max(100).optional(),
  ram_threshold_pct: z.number().min(0).max(100).optional(),
  disk_threshold_pct: z.number().min(0).max(100).optional(),
  disk_io_read_threshold: z.number().min(0).optional(),
  disk_io_write_threshold: z.number().min(0).optional(),
  network_in_threshold: z.number().min(0).optional(),
  network_out_threshold: z.number().min(0).optional(),
  consecutive_breaches: z.number().int().min(1).max(20).optional(),
  evaluation_window_minutes: z.number().int().min(1).max(1440).optional(),
  severity: z.nativeEnum(Severity).optional(),
  channels: z.array(z.nativeEnum(AlertChannel)).optional(),
  enabled: z.boolean().optional(),
  metadata: z.record(z.unknown()).optional()
});

async function ensureVmTenantScope(vmId: string, req: Pick<Express.Request, "user">) {
  const vm = await prisma.virtualMachine.findUnique({
    where: { id: vmId },
    select: {
      id: true,
      tenant_id: true,
      name: true
    }
  });

  if (!vm) {
    throw new HttpError(404, "VM not found", "VM_NOT_FOUND");
  }

  if (isTenantScopedUser(req) && req.user?.tenant_id && vm.tenant_id !== req.user.tenant_id) {
    throw new HttpError(403, "Access denied for tenant scope", "TENANT_SCOPE_VIOLATION");
  }

  return vm;
}

function scopedTenantId(req: Pick<Express.Request, "user">) {
  return isTenantScopedUser(req) ? req.user?.tenant_id ?? undefined : undefined;
}

function queryTenantId(req: { query?: Record<string, unknown> }) {
  return typeof req.query?.tenant_id === "string" ? req.query.tenant_id : undefined;
}

router.get("/overview", requireAuth, authorize("security:read"), async (req, res, next) => {
  try {
    const data = await monitoringOverview({
      tenant_id: scopedTenantId(req)
    });
    return res.json(data);
  } catch (error) {
    return next(error);
  }
});

router.get("/health-checks", requireAuth, authorize("security:read"), async (req, res, next) => {
  try {
    const data = await listHealthChecks({
      tenant_id: scopedTenantId(req) ?? queryTenantId(req),
      enabled: typeof req.query.enabled === "string" ? req.query.enabled === "true" : undefined
    });
    return res.json({ data });
  } catch (error) {
    return next(error);
  }
});

router.post("/health-checks", requireAuth, authorize("security:manage"), async (req, res, next) => {
  try {
    const payload = healthCheckSchema.parse(req.body ?? {});

    if (payload.vm_id) {
      await ensureVmTenantScope(payload.vm_id, req);
    }

    const tenantId = scopedTenantId(req) ?? payload.tenant_id;
    const check = await createHealthCheckDefinition({
      ...payload,
      tenant_id: tenantId,
      created_by: req.user?.email
    });

    await logAudit({
      action: "monitoring.health_check.create",
      resource_type: "SECURITY",
      resource_id: check.id,
      resource_name: check.name,
      actor_email: req.user!.email,
      actor_role: req.user!.role,
      details: toPrismaJsonValue(payload),
      ip_address: req.ip
    });

    return res.status(201).json(check);
  } catch (error) {
    return next(error);
  }
});

router.patch("/health-checks/:id", requireAuth, authorize("security:manage"), async (req, res, next) => {
  try {
    const payload = healthCheckSchema.partial().parse(req.body ?? {});
    const existing = await prisma.serverHealthCheck.findUnique({
      where: { id: req.params.id },
      select: {
        id: true,
        tenant_id: true
      }
    });

    if (!existing) {
      throw new HttpError(404, "Health check not found", "HEALTH_CHECK_NOT_FOUND");
    }

    if (isTenantScopedUser(req) && req.user?.tenant_id && existing.tenant_id && existing.tenant_id !== req.user.tenant_id) {
      throw new HttpError(403, "Access denied for tenant scope", "TENANT_SCOPE_VIOLATION");
    }

    if (payload.vm_id) {
      await ensureVmTenantScope(payload.vm_id, req);
    }

    const updated = await updateHealthCheckDefinition(req.params.id, {
      ...payload,
      tenant_id: scopedTenantId(req) ?? payload.tenant_id
    });

    return res.json(updated);
  } catch (error) {
    return next(error);
  }
});

router.post("/health-checks/:id/run", requireAuth, authorize("security:manage"), async (req, res, next) => {
  try {
    const existing = await prisma.serverHealthCheck.findUnique({
      where: { id: req.params.id },
      select: { id: true, tenant_id: true }
    });

    if (!existing) {
      throw new HttpError(404, "Health check not found", "HEALTH_CHECK_NOT_FOUND");
    }

    if (isTenantScopedUser(req) && req.user?.tenant_id && existing.tenant_id && existing.tenant_id !== req.user.tenant_id) {
      throw new HttpError(403, "Access denied for tenant scope", "TENANT_SCOPE_VIOLATION");
    }

    const result = await runHealthCheckNow(existing.id);
    return res.json(result);
  } catch (error) {
    return next(error);
  }
});

router.get("/health-checks/:id/results", requireAuth, authorize("security:read"), async (req, res, next) => {
  try {
    const existing = await prisma.serverHealthCheck.findUnique({
      where: { id: req.params.id },
      select: { id: true, tenant_id: true }
    });

    if (!existing) {
      throw new HttpError(404, "Health check not found", "HEALTH_CHECK_NOT_FOUND");
    }

    if (isTenantScopedUser(req) && req.user?.tenant_id && existing.tenant_id && existing.tenant_id !== req.user.tenant_id) {
      throw new HttpError(403, "Access denied for tenant scope", "TENANT_SCOPE_VIOLATION");
    }

    const limit = typeof req.query.limit === "string" ? Number(req.query.limit) : undefined;
    const data = await listHealthCheckResults(existing.id, limit);
    return res.json({ data });
  } catch (error) {
    return next(error);
  }
});

router.get("/alerts/rules", requireAuth, authorize("security:read"), async (req, res, next) => {
  try {
    const data = await listAlertRules({
      tenant_id: scopedTenantId(req) ?? queryTenantId(req),
      enabled: typeof req.query.enabled === "string" ? req.query.enabled === "true" : undefined
    });
    return res.json({ data });
  } catch (error) {
    return next(error);
  }
});

router.post("/alerts/rules", requireAuth, authorize("security:manage"), async (req, res, next) => {
  try {
    const payload = alertRuleSchema.parse(req.body ?? {});

    if (payload.vm_id) {
      await ensureVmTenantScope(payload.vm_id, req);
    }

    const tenantId = scopedTenantId(req) ?? payload.tenant_id;
    const rule = await createAlertRule({
      ...payload,
      tenant_id: tenantId,
      created_by: req.user?.email
    });

    await logAudit({
      action: "monitoring.alert_rule.create",
      resource_type: "SECURITY",
      resource_id: rule.id,
      resource_name: rule.name,
      actor_email: req.user!.email,
      actor_role: req.user!.role,
      details: toPrismaJsonValue(payload),
      ip_address: req.ip
    });

    return res.status(201).json(rule);
  } catch (error) {
    return next(error);
  }
});

router.patch("/alerts/rules/:id", requireAuth, authorize("security:manage"), async (req, res, next) => {
  try {
    const payload = alertRuleSchema.partial().parse(req.body ?? {});
    const existing = await prisma.monitoringAlertRule.findUnique({
      where: { id: req.params.id },
      select: {
        id: true,
        tenant_id: true
      }
    });

    if (!existing) {
      throw new HttpError(404, "Alert rule not found", "ALERT_RULE_NOT_FOUND");
    }

    if (isTenantScopedUser(req) && req.user?.tenant_id && existing.tenant_id && existing.tenant_id !== req.user.tenant_id) {
      throw new HttpError(403, "Access denied for tenant scope", "TENANT_SCOPE_VIOLATION");
    }

    if (payload.vm_id) {
      await ensureVmTenantScope(payload.vm_id, req);
    }

    const updated = await updateAlertRule(req.params.id, {
      ...payload,
      tenant_id: scopedTenantId(req) ?? payload.tenant_id
    });
    return res.json(updated);
  } catch (error) {
    return next(error);
  }
});

router.get("/alerts/events", requireAuth, authorize("security:read"), async (req, res, next) => {
  try {
    const statusRaw = typeof req.query.status === "string" ? req.query.status.toUpperCase() : undefined;
    const status = Object.values(MonitoringAlertStatus).includes(statusRaw as MonitoringAlertStatus)
      ? (statusRaw as MonitoringAlertStatus)
      : undefined;

    const limit = typeof req.query.limit === "string" ? Number(req.query.limit) : undefined;
    const data = await listAlertEvents({
      tenant_id: scopedTenantId(req) ?? queryTenantId(req),
      status,
      limit
    });
    return res.json({ data });
  } catch (error) {
    return next(error);
  }
});

router.get("/alerts/notifications", requireAuth, authorize("security:read"), async (req, res, next) => {
  try {
    const limit = typeof req.query.limit === "string" ? Number(req.query.limit) : undefined;
    const data = await listAlertNotifications({
      tenant_id: scopedTenantId(req) ?? queryTenantId(req),
      limit
    });
    return res.json({ data });
  } catch (error) {
    return next(error);
  }
});

router.post("/alerts/evaluate", requireAuth, authorize("security:manage"), async (req, res, next) => {
  try {
    const result = await evaluateAlertRulesNow(scopedTenantId(req));
    return res.json(result);
  } catch (error) {
    return next(error);
  }
});

router.get("/insights/faulty-deployments", requireAuth, authorize("security:read"), async (req, res, next) => {
  try {
    const days = typeof req.query.days === "string" ? Number(req.query.days) : undefined;
    const data = await faultyDeploymentInsights({
      days,
      tenant_id: scopedTenantId(req) ?? queryTenantId(req)
    });
    return res.json(data);
  } catch (error) {
    return next(error);
  }
});

router.get("/insights/cluster-forecast", requireAuth, authorize("security:read"), async (req, res, next) => {
  try {
    const horizon = typeof req.query.horizon_days === "string" ? Number(req.query.horizon_days) : undefined;
    const data = await clusterResourceForecast({
      horizon_days: horizon,
      tenant_id: scopedTenantId(req) ?? queryTenantId(req)
    });
    return res.json(data);
  } catch (error) {
    return next(error);
  }
});

export default router;