//
//  CoreDataMigrationTests.swift
//  LoopKitHostedTests
//
//  Created by Rick Pasetto on 8/9/21.
//  Copyright © 2021 LoopKit Authors. All rights reserved.
//

import CoreData
import HealthKit
import XCTest
@testable import LoopKit

class CoreDataV1MigrationTests: XCTestCase {
    
    var cacheStore: PersistenceController!
    let fileManager = FileManager()
    static let bundleURL = Bundle(for: CoreDataV1MigrationTests.self).bundleURL

    override func setUpWithError() throws {
        try? fileManager.removeItem(at: Self.bundleURL.appendingPathComponent("Model.sqlite"))
        try fileManager.copyItem(at: Self.bundleURL.appendingPathComponent("Model.sqlite.v1.original"),
                                 to: Self.bundleURL.appendingPathComponent("Model.sqlite"))
    }

    override func tearDownWithError() throws {
        
        // remove all stores
        try cacheStore.managedObjectContext.persistentStoreCoordinator?.persistentStores.forEach { store in
            try cacheStore.managedObjectContext.persistentStoreCoordinator?.remove(store)
        }
        
        try fileManager.removeItem(at: Self.bundleURL.appendingPathComponent("Model.sqlite"))
        cacheStore = nil
    }

    func testV1Migration() throws {
        let e = expectation(description: "\(#function): init")
        cacheStore = PersistenceController.init(directoryURL: Self.bundleURL)
        var error: Error?
        cacheStore.onReady {
            if let err = $0 {
                error = err
                XCTFail("Error opening \(Self.bundleURL): \(err)")
            }
            e.fulfill()
        }
        wait(for: [e], timeout: 10.0)
        if let error = error { throw error }        
        var entries: [CachedCarbObject]!
        let e0 = expectation(description: "\(#function): fetch")
        cacheStore.managedObjectContext.performAndWait {
            do {
                entries = try cacheStore.managedObjectContext.fetch(CachedCarbObject.fetchRequest())
            } catch let err {
                error = err
            }
            e0.fulfill()
        }
        wait(for: [e0], timeout: 1.0)
        if let error = error { throw error }
        XCTAssertEqual(1, entries.count)
        
        // Do some spot checks.
        XCTAssertTrue(entityHasAttribute(entityName: "CachedGlucoseObject", attributeName: "device"))
        XCTAssertTrue(entityHasAttribute(entityName: "CachedGlucoseObject", attributeName: "trend"))
    }
    
    func entityHasAttribute(entityName: String, attributeName: String) -> Bool {
        XCTAssertNotNil(cacheStore.managedObjectContext.persistentStoreCoordinator?.managedObjectModel.entities)
        if let entities = cacheStore.managedObjectContext.persistentStoreCoordinator?.managedObjectModel.entities {
            for entity in entities {
                if entity.name == entityName, entity.attributesByName.contains(where: { (key: String, value: NSAttributeDescription) in
                    key == attributeName
                }) {
                    return true
                }
            }
        }
        return false
    }
}