//
//  SwapModelPool.swift
//  Wallet
//
//  Created by Saveliy Stavitsky on 3/18/21.
//  Copyright © 2021 AM. All rights reserved.
//

import Foundation

extension Swap.Model {
    struct Pool: Decodable {
        let id: Int
        let code: String
        let k: Decimal // swiftlint:disable:this identifier_name
        let totalFee: Decimal
        let kDouble: Double
        let totalFeeDouble: Double

        private let parsedToken1: Network.Model.TokenSmallParsed
        private let parsedToken2: Network.Model.TokenSmallParsed

        private(set) var isReversed: Bool = false
        func reversed() -> Pool {
            var newPool = self
            newPool.isReversed = true
            return newPool
        }

        var token1: Network.Model.Token? { isReversed ? parsedToken2.asToken : parsedToken1.asToken }
        var token2: Network.Model.Token? { isReversed ? parsedToken1.asToken : parsedToken2.asToken }
        var token1Light: Network.Model.TokenSmallParsed? { isReversed ? parsedToken2 : parsedToken1 }
        var token2Light: Network.Model.TokenSmallParsed? { isReversed ? parsedToken1 : parsedToken2 }

        var forwardExchangeRate: Decimal { (token2?.amount ?? 0) / (token1?.amount ?? 1.0) }
        var backwardExchangeRate: Decimal { (token1?.amount ?? 0) / (token2?.amount ?? 1.0) }

        enum CodingKeys: String, CodingKey {
            case id
            case code
            case token1
            case token2

            case poolFee = "pool_fee"
            case platformFee = "platform_fee"
        }

        init(from decoder: Decoder) throws {
            let values = try decoder.container(keyedBy: CodingKeys.self)
            id = try values.decode(Int.self, forKey: .id)
            code = try values.decode(String.self, forKey: .code)

            let token1 = try values.decode(Network.Model.TokenSmall.self, forKey: .token1).asToken
            parsedToken1 = Network.Model.TokenSmallParsed(
                amount: token1?.amount ?? 0,
                amountDouble: NSDecimalNumber(decimal: (token1?.amount ?? 0)).doubleValue,
                id: "\(token1?.symbol ?? "")#\(token1?.contract ?? "")",
                symbol: token1?.symbol ?? "",
                contract: token1?.contract ?? "",
                precision: token1?.precision ?? 0)
            let token2 = try values.decode(Network.Model.TokenSmall.self, forKey: .token2).asToken
            parsedToken2 = Network.Model.TokenSmallParsed(
                amount: token2?.amount ?? 0,
                amountDouble: NSDecimalNumber(decimal: (token2?.amount ?? 0)).doubleValue,
                id: "\(token2?.symbol ?? "")#\(token2?.contract ?? "")",
                symbol: token2?.symbol ?? "",
                contract: token2?.contract ?? "",
                precision: token2?.precision ?? 0)
            k = (token1?.amount ?? 0) * (token2?.amount ?? 0)
            kDouble = NSDecimalNumber(decimal: k).doubleValue

            let poolFee = try values.decode(String.self, forKey: .poolFee).amount.toDecimal() / 100.0
            let platformFee = try values.decode(String.self, forKey: .platformFee).amount.toDecimal() / 100.0
            totalFee = poolFee + platformFee
            totalFeeDouble = NSDecimalNumber(decimal: totalFee).doubleValue
        }

        let cashContractName = ApplicationEnvironment.shared().current.contract(.cash)

        func processSend(amount: Decimal, forward: Bool) -> Decimal {
//            guard let token1 = (token1 == amountToken ? token1 : token2),
//                  let token2 = (token1 == amountToken ? token2 : token1),
//                  token1 == amountToken || token2 == amountToken else {
//                return 0
//            }
            guard let token1 = forward ? self.token1Light : self.token2Light,
                  let token2 = forward ? self.token2Light : self.token1Light else {
                return 0
            }
            let minTokenAmount = (Decimal(1) / pow(Decimal(10), token1.precision))

            if amount < Decimal(800) * minTokenAmount {
                return 0
            }

            let withoutCommission = amount
                .receive(percent: totalFee, precision: token1.precision, ignoreMaxCommission: true)
            let newPool = token1.amount + withoutCommission
            let otherTokenNewPool = (k / newPool).roundDown(to: token2.precision)
            return token2.amount - otherTokenNewPool
        }

        func processReceive(amount: Decimal, forward: Bool) -> Decimal {
            guard let tokenTo = forward ? self.token2Light : self.token1Light,
                  let tokenFrom = forward ? self.token1Light : self.token2Light else {
                return 0
            }

            let newPool = (tokenFrom.amount - amount).roundDown(to: tokenFrom.precision)
            let otherTokenNewPool = (k / newPool).roundDown(to: tokenTo.precision)
            let withCommission = (otherTokenNewPool - tokenTo.amount)
                .send(percent: totalFee, precision: tokenTo.precision, ignoreMaxCommission: true)

//            let minTokenAmount = (Decimal(1) / pow(Decimal(10), tokenTo.precision))
//            if tokenTo.contract == cashContractName && withCommission < Decimal(4000) * minTokenAmount {
//                return Decimal(4000) * minTokenAmount
//            }
//            if withCommission < Decimal(800) * minTokenAmount {
//                return Decimal(800) * minTokenAmount
//            }
            return withCommission
        }
    }

    struct PoolStat: Codable {
        let supply: String
        var token: Network.Model.Token? {
            Network.Model.Token(
                symbol: supply.symbol,
                precision: 0,
                amount: supply.amount.toDecimal(),
                contract: ApplicationEnvironment.shared().current.contract(.swap)
            )
        }
    }
}

struct SpeedPool: Hashable {
    let id: Int
    private(set) var isReversed: Bool = false
    func reversed() -> SpeedPool {
        var newPool = self
        newPool.isReversed = true
        return newPool
    }
    let token1Code: Int
    let token2Code: Int
    var token1: Int { isReversed ? token2Code : token1Code }
    var token2: Int { isReversed ? token1Code : token2Code }

    func hash(into hasher: inout Hasher) {
        hasher.combine(id)
    }
}

extension SpeedPool: Equatable {
    static func == (lhs: SpeedPool, rhs: SpeedPool) -> Bool {
        lhs.id == rhs.id
    }
}