/**
 * Subscription History Cache
 * 
 * Caches customer subscription history to avoid expensive Stripe API calls
 * during promo eligibility checks. Updated via webhook sync and CLI script.
 * 
 * Use Cases:
 * - Check if customer has ever subscribed to a specific type/price
 * - Determine eligibility for "new customer only" or "returning customer" promos
 * - Query local DB instead of Stripe API for better performance
 */

const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const { SubStatus, SubType } = require('./subscription');

const subscriptionHistorySchema = new Schema({
  // Stripe customer ID (indexed for fast lookup)
  custId: {
    type: String,
    required: true,
    index: true
  },

  // Subscription type ('package' or 'addon')
  type: {
    type: String,
    enum: Object.values(SubType),
    required: true,
    index: true
  },

  // price's lookup_key (e.g., 'ess_1', 'addon_1') - optional for type-level history
  priceKey: {
    type: String,
    sparse: true,
    index: true
  },

  // History summary
  firstSubscribedAt: {
    type: Date,
    required: true
  },

  lastSubscribedAt: {
    type: Date,
    required: true
  },

  totalSubscriptions: {
    type: Number,
    default: 1,
    min: 1
  },

  // Track active subscription ID if exists
  currentSubscriptionId: {
    type: String
  },

  // Last subscription status (to know what happened with most recent subscription)
  lastSubscriptionStatus: {
    type: String,
    enum: Object.values(SubStatus)
  },

  // Last sync timestamp (to know when cache was updated)
  lastSyncedAt: {
    type: Date,
    default: Date.now
  }
}, {
  timestamps: true,
  collection: 'subscription_histories'
});

// Compound index for fast eligibility checks
subscriptionHistorySchema.index({ custId: 1, type: 1, priceKey: 1 });

// Index for cleanup queries
subscriptionHistorySchema.index({ lastSyncedAt: 1 });

module.exports = mongoose.model('SubscriptionHistory', subscriptionHistorySchema);