import { and, eq, gte } from "drizzle-orm";
import { getDb, getSubscription } from "../db.js";
import { clinics, queueEntries } from "../schema.js";
import { sql } from "drizzle-orm";

export type PlanFeature =
  | "maxClinics"
  | "maxQueueEntriesPerDay"
  | "multiPractitioner"
  | "analyticsExport";

type PlanLimits = {
  maxClinics: number;
  maxQueueEntriesPerDay: number;
  multiPractitioner: boolean;
  analyticsExport: boolean;
};

// trial == basic level access during trial period; pro lifts everything.
export const PLAN_LIMITS: Record<"trial" | "basic" | "pro", PlanLimits> = {
  trial: {
    maxClinics: 1,
    maxQueueEntriesPerDay: 50,
    multiPractitioner: false,
    analyticsExport: false,
  },
  basic: {
    maxClinics: 1,
    maxQueueEntriesPerDay: 200,
    multiPractitioner: false,
    analyticsExport: true,
  },
  pro: {
    maxClinics: Infinity,
    maxQueueEntriesPerDay: Infinity,
    multiPractitioner: true,
    analyticsExport: true,
  },
};

export type PlanLimitCheck =
  | { ok: true }
  | { ok: false; reason: string; feature: PlanFeature };

async function getUserPlan(userId: number): Promise<"trial" | "basic" | "pro"> {
  const sub = await getSubscription(userId);
  return sub?.plan ?? "trial";
}

function limits(plan: "trial" | "basic" | "pro"): PlanLimits {
  return PLAN_LIMITS[plan];
}

async function countClinicsForUser(userId: number): Promise<number> {
  const db = await getDb();
  const rows = await db
    .select({ count: sql<number>`COUNT(*)` })
    .from(clinics)
    .where(eq(clinics.userId, userId));
  return Number(rows[0]?.count ?? 0);
}

async function countQueueEntriesTodayForClinic(clinicId: number): Promise<number> {
  const db = await getDb();
  const startOfDay = new Date();
  startOfDay.setHours(0, 0, 0, 0);
  const rows = await db
    .select({ count: sql<number>`COUNT(*)` })
    .from(queueEntries)
    .where(
      and(eq(queueEntries.clinicId, clinicId), gte(queueEntries.joinedAt, startOfDay))
    );
  return Number(rows[0]?.count ?? 0);
}

const FEATURE_MESSAGES: Record<PlanFeature, string> = {
  maxClinics: "Limite de cabinets atteinte : passez au plan Pro pour en créer plus.",
  maxQueueEntriesPerDay:
    "Limite quotidienne de patients atteinte : passez au plan Pro pour des inscriptions illimitées.",
  multiPractitioner:
    "La gestion multi-praticiens est réservée au plan Pro. Mettez à niveau pour ajouter des praticiens.",
  analyticsExport:
    "L'export des statistiques est réservé aux plans payants. Mettez à niveau pour exporter vos données.",
};

export async function checkPlanLimit(
  userId: number,
  feature: PlanFeature,
  context: { clinicId?: number } = {}
): Promise<PlanLimitCheck> {
  const plan = await getUserPlan(userId);
  const max = limits(plan);

  switch (feature) {
    case "maxClinics": {
      if (max.maxClinics === Infinity) return { ok: true };
      const current = await countClinicsForUser(userId);
      if (current >= max.maxClinics) {
        return { ok: false, feature, reason: FEATURE_MESSAGES.maxClinics };
      }
      return { ok: true };
    }
    case "maxQueueEntriesPerDay": {
      if (max.maxQueueEntriesPerDay === Infinity) return { ok: true };
      if (!context.clinicId) return { ok: true };
      const today = await countQueueEntriesTodayForClinic(context.clinicId);
      if (today >= max.maxQueueEntriesPerDay) {
        return {
          ok: false,
          feature,
          reason: FEATURE_MESSAGES.maxQueueEntriesPerDay,
        };
      }
      return { ok: true };
    }
    case "multiPractitioner": {
      if (max.multiPractitioner) return { ok: true };
      return { ok: false, feature, reason: FEATURE_MESSAGES.multiPractitioner };
    }
    case "analyticsExport": {
      if (max.analyticsExport) return { ok: true };
      return { ok: false, feature, reason: FEATURE_MESSAGES.analyticsExport };
    }
  }
}

export async function getPlanLimitsForUser(userId: number): Promise<{
  plan: "trial" | "basic" | "pro";
  limits: PlanLimits;
}> {
  const plan = await getUserPlan(userId);
  return { plan, limits: limits(plan) };
}