import Foundation
import XCTest
@testable import DocsKit

final class CRDTGenerationTests: XCTestCase {
    @MainActor func testDelayedPresentationDoesNotReplaceSourceOfQueuedTyping() async throws {
        let replica = CRDTReplica(guid: "native-generation-test")
        _ = try await replica.open(update: Data())
        _ = try await replica.command(["op": .string("insert_element"), "at": .number(0), "type": .string("paragraph")])
        let first = try await replica.presentation(source: 0, selection: NSRange(location: 0, length: 0))
        let source = try XCTUnwrap(first?.0)
        var published = source
        let characters = Array("Native text".unicodeScalars)
        for (index, scalar) in characters.enumerated() {
            _ = try await replica.command(["op": .string("display_edit"), "generation": .number(Double(source)), "at": .number(Double(index)), "length": .number(0), "text": .string(String(scalar))])
            await replica.retainGenerations([source, published])
            let candidate = try await replica.presentation(source: source, selection: NSRange(location: index + 1, length: 0))
            published = try XCTUnwrap(candidate?.0)
            // Deliberately withhold render acknowledgement: the next callback
            // still belongs to the original displayed source, not this candidate.
        }
        let final = try await replica.projection()
        XCTAssertEqual(final.children.map(\.plainText).joined(), "Native text")
        XCTAssertTrue(final.canUndo)
        _ = try await replica.command(["op": .string("display_edit"), "generation": .number(Double(published)), "at": .number(11), "length": .number(0), "text": .string(" bold"), "marks": .object(["strong": .object([:])])])
        let formatted = try await replica.projection()
        XCTAssertEqual(formatted.children.map(\.plainText).joined(), "Native text bold")
        XCTAssertEqual(formatted.children[0].children?.last?.runs?.last?.marks?["strong"], .object([:]))
        await replica.close()
    }
}