import XCTest
import SwiftData
@testable import MindDump

final class TodoItemTests: XCTestCase {

    // MARK: - isOverdue

    // Past deadline should be overdue
    func testIsOverdue_deadlineYesterday_returnsTrue() {
        let yesterday = Calendar.current.date(byAdding: .day, value: -1, to: Date())!
        let item = TodoItem(title: "Test", deadline: yesterday)
        XCTAssertTrue(item.isOverdue)
    }

    // Completed items are never overdue, even with past deadline
    func testIsOverdue_completedWithPastDeadline_returnsFalse() {
        let yesterday = Calendar.current.date(byAdding: .day, value: -1, to: Date())!
        let item = TodoItem(title: "Test", isCompleted: true, deadline: yesterday)
        XCTAssertFalse(item.isOverdue)
    }


}

final class TodoListTests: XCTestCase {

    // MARK: - openItems / completedItems

    // Items are correctly split into open and completed
    func testOpenAndCompletedItems_correctSplit() {
        let open1 = TodoItem(title: "Open 1")
        let open2 = TodoItem(title: "Open 2")
        let done = TodoItem(title: "Done", isCompleted: true)

        let list = TodoList(name: "Test", items: [open1, done, open2])

        XCTAssertEqual(list.openItems.count, 2)
        XCTAssertEqual(list.completedItems.count, 1)
        XCTAssertEqual(list.completedItems.first?.title, "Done")
    }

    // Open items are sorted oldest first
    func testOpenItems_sortedByCreatedAtAscending() {
        let older = TodoItem(title: "Older", createdAt: Date().addingTimeInterval(-100))
        let newer = TodoItem(title: "Newer", createdAt: Date())

        let list = TodoList(name: "Test", items: [newer, older])

        XCTAssertEqual(list.openItems.map(\.title), ["Older", "Newer"])
    }

    // Completed items are sorted newest first (by modifiedAt)
    func testCompletedItems_sortedByModifiedAtDescending() {
        let earlier = TodoItem(title: "Earlier", isCompleted: true, modifiedAt: Date().addingTimeInterval(-100))
        let later = TodoItem(title: "Later", isCompleted: true, modifiedAt: Date())

        let list = TodoList(name: "Test", items: [earlier, later])

        XCTAssertEqual(list.completedItems.map(\.title), ["Later", "Earlier"])
    }

}

// MARK: - ListStore Tests

@MainActor
final class ListStoreTests: XCTestCase {

    private var container: ModelContainer!
    private var store: ListStore!

    override func setUp() {
        let config = ModelConfiguration(isStoredInMemoryOnly: true)
        container = try! ModelContainer(for: TodoList.self, TodoItem.self, configurations: config)
        store = ListStore(modelContext: container.mainContext)
    }

    // MARK: - addItem / deleteItem

    // Adding an item increases the list count and stores the title
    func testAddItem_increasesCount() {
        let inboxID = store.inboxID
        store.addItem(to: inboxID, title: "Buy milk")

        XCTAssertEqual(store.lists.first!.items.count, 1)
        XCTAssertEqual(store.lists.first!.items.first?.title, "Buy milk")
    }

    // Deleting an item removes it from the list
    func testDeleteItem_removesItem() {
        let inboxID = store.inboxID
        store.addItem(to: inboxID, title: "Temp")
        let itemID = store.lists.first!.items.first!.id

        store.deleteItem(itemID, from: inboxID)

        XCTAssertTrue(store.lists.first!.items.isEmpty)
    }

    // MARK: - toggleItemCompleted

    // Toggling flips isCompleted back and forth
    func testToggleItemCompleted_flipsStatus() {
        let inboxID = store.inboxID
        store.addItem(to: inboxID, title: "Task")
        let itemID = store.lists.first!.items.first!.id

        XCTAssertFalse(store.lists.first!.items.first!.isCompleted)

        store.toggleItemCompleted(itemID, in: inboxID)
        XCTAssertTrue(store.lists.first!.items.first!.isCompleted)

        store.toggleItemCompleted(itemID, in: inboxID)
        XCTAssertFalse(store.lists.first!.items.first!.isCompleted)
    }

    // MARK: - moveItem

    // Moving an item removes it from the source list, adds it to the target list, and updates modifiedAt
    func testMoveItem_movesAcrossLists() {
        let inboxID = store.inboxID
        store.addList(name: "Arbeit")
        let arbeitID = store.lists.first { $0.name == "Arbeit" }!.id

        store.addItem(to: inboxID, title: "Wichtige Aufgabe")
        let itemID = store.lists.first { $0.isInbox }!.items.first!.id

        store.moveItem(itemID, from: inboxID, to: arbeitID)

        let inbox = store.lists.first { $0.isInbox }!
        let arbeit = store.lists.first { $0.name == "Arbeit" }!

        XCTAssertTrue(inbox.items.isEmpty, "Item should be removed from source lists")
        XCTAssertEqual(arbeit.items.count, 1, "Item should be in target list")
        XCTAssertEqual(arbeit.items.first?.title, "Wichtige Aufgabe")
        XCTAssertNotNil(arbeit.items.first?.modifiedAt, "modifiedAt should be set after move")
    }
}