//
//  Copyright RevenueCat Inc. All Rights Reserved.
//
//  Licensed under the MIT License (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//      https://opensource.org/licenses/MIT
//
//  PostReceiptDataOperation.swift
//
//  Created by Joshua Liebowitz on 11/18/21.

import Foundation

final class PostReceiptDataOperation: CacheableNetworkOperation {

    struct PostData {

        let appUserID: String
        let receiptData: Data
        let isRestore: Bool
        let productData: ProductRequestData?
        let presentedOfferingIdentifier: String?
        let observerMode: Bool
        let initiationSource: ProductRequestData.InitiationSource
        let subscriberAttributesByKey: SubscriberAttribute.Dictionary?

    }

    private let postData: PostData
    private let configuration: AppUserConfiguration
    private let customerInfoResponseHandler: CustomerInfoResponseHandler
    private let customerInfoCallbackCache: CallbackCache<CustomerInfoCallback>

    static func createFactory(
        configuration: UserSpecificConfiguration,
        postData: PostData,
        customerInfoResponseHandler: CustomerInfoResponseHandler = CustomerInfoResponseHandler(),
        customerInfoCallbackCache: CallbackCache<CustomerInfoCallback>
    ) -> CacheableNetworkOperationFactory<PostReceiptDataOperation> {
        /// Cache key comprises of the following:
        /// - `appUserID`
        /// - `isRestore`
        /// - Receipt (`hashString` instead of `fetchToken` to avoid big receipts leading to a huge cache key)
        /// - `ProductRequestData.cacheKey`
        /// - `presentedOfferingIdentifier`
        /// - `observerMode`
        /// - `subscriberAttributesByKey`
        let cacheKey =
        """
        \(configuration.appUserID)-\(postData.isRestore)-\(postData.receiptData.hashString)
        -\(postData.productData?.cacheKey ?? "")
        -\(postData.presentedOfferingIdentifier ?? "")-\(postData.observerMode)
        -\(postData.subscriberAttributesByKey?.debugDescription ?? "")"
        """

        return .init({ cacheKey in
                    .init(
                        configuration: configuration,
                        postData: postData,
                        customerInfoResponseHandler: customerInfoResponseHandler,
                        customerInfoCallbackCache: customerInfoCallbackCache,
                        cacheKey: cacheKey
                    )
            },
            individualizedCacheKeyPart: cacheKey
        )
    }

    private init(
        configuration: UserSpecificConfiguration,
        postData: PostData,
        customerInfoResponseHandler: CustomerInfoResponseHandler,
        customerInfoCallbackCache: CallbackCache<CustomerInfoCallback>,
        cacheKey: String
    ) {
        self.customerInfoResponseHandler = customerInfoResponseHandler
        self.customerInfoCallbackCache = customerInfoCallbackCache
        self.postData = postData
        self.configuration = configuration

        super.init(configuration: configuration, cacheKey: cacheKey)
    }

    override func begin(completion: @escaping () -> Void) {
        if Logger.logLevel <= .debug {
            self.printReceiptData()
        }

        self.post(completion: completion)
    }

    private func post(completion: @escaping () -> Void) {
        let request = HTTPRequest(method: .post(self.postData), path: .postReceiptData)

        httpClient.perform(request) { (response: HTTPResponse<CustomerInfoResponseHandler.Response>.Result) in
            self.customerInfoCallbackCache.performOnAllItemsAndRemoveFromCache(withCacheable: self) { callbackObject in
                self.customerInfoResponseHandler.handle(customerInfoResponse: response,
                                                        completion: callbackObject.completion)
            }

            completion()
        }
    }

}

// MARK: - Private

private extension PostReceiptDataOperation {

    func printReceiptData() {
        do {
            let receipt = try PurchasesReceiptParser.default.parse(from: self.postData.receiptData)
            self.log(Strings.receipt.posting_receipt(receipt))

            for purchase in receipt.inAppPurchases where purchase.purchaseDateEqualsExpiration {
                Logger.appleError(Strings.receipt.receipt_subscription_purchase_equals_expiration(
                    productIdentifier: purchase.productId,
                    purchase: purchase.purchaseDate,
                    expiration: purchase.expiresDate
                ))
            }

        } catch {
            Logger.appleError(Strings.receipt.parse_receipt_locally_error(error: error))
        }
    }

}

// MARK: - Request Data

extension PostReceiptDataOperation.PostData: Encodable {

    private enum CodingKeys: String, CodingKey {

        case fetchToken
        case appUserID
        case isRestore
        case observerMode
        case initiationSource
        case attributes
        case presentedOfferingIdentifier

    }

    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)

        try container.encode(self.receiptData.asFetchToken, forKey: .fetchToken)
        try container.encode(self.appUserID, forKey: .appUserID)
        try container.encode(self.isRestore, forKey: .isRestore)
        try container.encode(self.observerMode, forKey: .observerMode)
        try container.encode(self.initiationSource, forKey: .initiationSource)

        if let productData = self.productData {
            try productData.encode(to: encoder)
        }

        try container.encodeIfPresent(self.presentedOfferingIdentifier,
                                      forKey: .presentedOfferingIdentifier)

        try container.encodeIfPresent(
            self.subscriberAttributesByKey
                .map(SubscriberAttribute.map)
                .map(AnyEncodable.init),
            forKey: .attributes
        )
    }

}

// MARK: - InitiationSource

extension ProductRequestData.InitiationSource: Encodable, RawRepresentable {

    var rawValue: String {
        switch self {
        case .restore: return "restore"
        case .purchase: return "purchase"
        case .queue: return "queue"
        }
    }

    init?(rawValue: String) {
        guard let value = Self.codes[rawValue] else { return nil }

        self = value
    }

    private static let codes: [String: ProductRequestData.InitiationSource] = Self
        .allCases
        .dictionaryWithKeys { $0.rawValue }

}