//
//  ReOrgTests.swift
//  ZcashLightClientKit-Unit-Tests
//
//  Created by Francisco Gindre on 3/23/20.
//

import XCTest
@testable import ZcashLightClientKit
/**
 basic reorg test.  Scan, get a reorg and then reach latest height.
 
 * connect to dLWD
 * request latest height -> receive 663250
 * download and sync blocks from 663150 to 663250
 * trigger reorg by calling API (no need to pass params)**
 * request latest height -> receive 663251!
 * download that block
 * observe that the prev hash of that block does not match the hash that we have for 663250
 * rewind 10 blocks and request blocks 663241 to 663251
 */
class ReOrgTests: XCTestCase {
    var seedPhrase = "still champion voice habit trend flight survey between bitter process artefact blind carbon truly provide dizzy crush flush breeze blouse charge solid fish spread" //TODO: Parameterize this from environment?
       
       let testRecipientAddress = "zs17mg40levjezevuhdp5pqrd52zere7r7vrjgdwn5sj4xsqtm20euwahv9anxmwr3y3kmwuz8k55a" //TODO: Parameterize this from environment
       
       let sendAmount: Int64 = 1000
       var birthday: BlockHeight = 663150
       let defaultLatestHeight: BlockHeight = 663175
       var coordinator: TestCoordinator!
       var syncedExpectation = XCTestExpectation(description: "synced")
       var sentTransactionExpectation = XCTestExpectation(description: "sent")
       var expectedReorgHeight: BlockHeight = 665188
       var expectedRewindHeight: BlockHeight = 665188
       var reorgExpectation: XCTestExpectation = XCTestExpectation(description: "reorg")
       override func setUpWithError() throws {
            NotificationCenter.default.addObserver(self, selector: #selector(handleReOrgNotification(_:)), name: Notification.Name.blockProcessorHandledReOrg, object: nil)
           coordinator = try TestCoordinator(
               seed: seedPhrase,
               walletBirthday: birthday,
               channelProvider: ChannelProvider()
           )
        try coordinator.reset(saplingActivation: birthday, branchID: "e9ff75a6", chainName: "main")
           try coordinator.resetBlocks(dataset: .default)
           
       }
       
       override func tearDownWithError() throws {
           try? FileManager.default.removeItem(at: coordinator.databases.cacheDB)
           try? FileManager.default.removeItem(at: coordinator.databases.dataDB)
           try? FileManager.default.removeItem(at: coordinator.databases.pendingDB)
       }
    let mockLatestHeight = BlockHeight(663250)
    let targetLatestHeight = BlockHeight(663251)
    let walletBirthday = BlockHeight(663150)
    
    
    
    @objc func handleReOrgNotification(_ notification: Notification) {
        
        reorgExpectation.fulfill()
        guard let reorgHeight = notification.userInfo?[CompactBlockProcessorNotificationKey.reorgHeight] as? BlockHeight,
            let rewindHeight = notification.userInfo?[CompactBlockProcessorNotificationKey.rewindHeight] as? BlockHeight else {
                XCTFail("malformed reorg userInfo")
                return
        }
        print("reorgHeight: \(reorgHeight)")
        print("rewindHeight: \(rewindHeight)")
        
        XCTAssertTrue(reorgHeight > 0)
        XCTAssertNoThrow(rewindHeight > 0)
    }
    
    func testBasicReOrg() throws {
        let mockLatestHeight = BlockHeight(663200)
        let targetLatestHeight = BlockHeight(663202)
        let reOrgHeight = BlockHeight(663195)
        let walletBirthday = WalletBirthday.birthday(with: 663150).height
        
        try basicReOrgTest(baseDataset: .beforeReOrg,
                            reorgDataset: .afterSmallReorg,
                            firstLatestHeight: mockLatestHeight,
                            reorgHeight: reOrgHeight,
                            walletBirthday: walletBirthday,
                            targetHeight: targetLatestHeight)
    }
    
    func testTenPlusBlockReOrg() throws {
        let mockLatestHeight = BlockHeight(663200)
        let targetLatestHeight = BlockHeight(663250)
        let reOrgHeight = BlockHeight(663180)
        let walletBirthday = WalletBirthday.birthday(with: BlockHeight(663150)).height
        
        try basicReOrgTest(baseDataset: .beforeReOrg,
                           reorgDataset: .afterLargeReorg,
                           firstLatestHeight: mockLatestHeight,
                           reorgHeight: reOrgHeight,
                           walletBirthday: walletBirthday,
                           targetHeight: targetLatestHeight)
    }
    
    func basicReOrgTest(baseDataset: DarksideDataset,
                        reorgDataset: DarksideDataset,
                        firstLatestHeight: BlockHeight,
                        reorgHeight: BlockHeight,
                        walletBirthday: BlockHeight,
                        targetHeight: BlockHeight) throws {
     
        do {
            try coordinator.reset(saplingActivation: birthday, branchID: "e9ff75a6", chainName: "main")
            try coordinator.resetBlocks(dataset: .predefined(dataset: .beforeReOrg))
            try coordinator.applyStaged(blockheight: firstLatestHeight)
        } catch  {
            XCTFail("Error: \(error)")
            return
        }

        let firstSyncExpectation = XCTestExpectation(description: "firstSyncExpectation")
        
        /**
         download and sync blocks from walletBirthday to firstLatestHeight
         */
        var synchronizer: SDKSynchronizer?
        try coordinator.sync(completion: { (s) in
            synchronizer = s
            firstSyncExpectation.fulfill()
        }, error: self.handleError)
       
        wait(for: [firstSyncExpectation], timeout: 5)
        
        guard let syncedSynchronizer = synchronizer else {
            XCTFail("nil synchronizer")
            return
        }
        /**
         verify that mock height has been reached
         */
        var latestDownloadedHeight = BlockHeight(0)
        XCTAssertNoThrow(try {latestDownloadedHeight = try syncedSynchronizer.initializer.downloader.latestBlockHeight()}())
        XCTAssertTrue(latestDownloadedHeight > 0)
        
        /**
         trigger reorg!
         */
      
        try coordinator.resetBlocks(dataset: .predefined(dataset: reorgDataset))
        try coordinator.applyStaged(blockheight: targetHeight)
     
        /**
         request latest height -> receive targetHeight!
         download that block
         observe that the prev hash of that block does not match the hash that we have for firstLatestHeight
         rewind 10 blocks and request blocks targetHeight-10 to targetHeight
         */
        
        let secondSyncExpectation = XCTestExpectation(description: "second sync")
        
        sleep(2)
        try coordinator.sync(completion: { (_) in
            secondSyncExpectation.fulfill()
               }, error: self.handleError)
        
        // now reorg should happen and reorg notifications and idle notification should be triggered
        
        wait(for: [reorgExpectation,secondSyncExpectation], timeout: 5)
        
        // now everything should be fine. latest block should be targetHeight
        
        XCTAssertNoThrow(try {latestDownloadedHeight = try syncedSynchronizer.initializer.downloader.latestBlockHeight()}())
        XCTAssertEqual(latestDownloadedHeight, targetHeight)
    }
    
    @objc func processorHandledReorg(_ notification: Notification) {
        
        XCTAssertNotNil(notification.userInfo)
        if let reorg = notification.userInfo?[CompactBlockProcessorNotificationKey.reorgHeight] as? BlockHeight,
            let rewind = notification.userInfo?[CompactBlockProcessorNotificationKey.rewindHeight] as? BlockHeight {
            
         
            XCTAssertTrue( rewind <= reorg )
            reorgExpectation.fulfill()
        } else {
            XCTFail("CompactBlockProcessor reorg notification is malformed")
        }
    }
    
    func handleError(_ error: Error?) {
        guard let testError = error else {
            XCTFail("failed with nil error")
            return
        }
        XCTFail("Failed with error: \(testError)")
    }
    
}