import SwiftData
import XCTest
@testable import ZitareNative

@MainActor
final class SnapshotSyncTests: XCTestCase {
    /// Erster Pull: 2 Quotes, beide werden persistiert.
    func test_persistsInitialPayload() async throws {
        let container = try SnapshotContainer.make(inMemory: true)
        let sync = SnapshotSync.forTesting(container: container) { Self.firstRun }
        try await sync.refresh()

        let context = ModelContext(container)
        let quotes = try context.fetch(FetchDescriptor<CachedQuote>())
        XCTAssertEqual(quotes.count, 2)
        let bySlug = Dictionary(uniqueKeysWithValues: quotes.map { ($0.slug, $0) })
        XCTAssertEqual(bySlug["spitteler-x"]?.authorName, "Carl Spitteler")
        XCTAssertEqual(bySlug["keller-x"]?.regions, ["zuerich", "schweiz"])

        let metas = try context.fetch(FetchDescriptor<SnapshotMeta>())
        XCTAssertEqual(metas.count, 1)
        XCTAssertEqual(metas.first?.totalCount, 2)
    }

    /// Zweiter Pull (gleicher Container): keller-x zurückgezogen,
    /// spitteler-x text geändert, neuere-x dazu → Update + Delete +
    /// Insert wie erwartet.
    func test_reconcilesOnSecondPull() async throws {
        let container = try SnapshotContainer.make(inMemory: true)
        let sync1 = SnapshotSync.forTesting(container: container) { Self.firstRun }
        try await sync1.refresh()
        let sync2 = SnapshotSync.forTesting(container: container) { Self.secondRun }
        try await sync2.refresh()

        let context = ModelContext(container)
        let after = try context.fetch(FetchDescriptor<CachedQuote>())
        let afterBySlug = Dictionary(uniqueKeysWithValues: after.map { ($0.slug, $0) })
        XCTAssertEqual(after.count, 2)
        XCTAssertEqual(afterBySlug["spitteler-x"]?.text, "A-updated")
        XCTAssertNotNil(afterBySlug["neuere-x"])
        XCTAssertNil(afterBySlug["keller-x"])
    }

    /// `refreshIfStale` macht kein Refresh, wenn lastSyncedAt frisch.
    func test_freshSnapshotSkipsRefresh() async throws {
        let container = try SnapshotContainer.make(inMemory: true)
        let sync = SnapshotSync.forTesting(
            container: container,
            staleAfter: 3600
        ) { Self.smallPayload }
        try await sync.refresh()

        // Loader, der explosiv knallt — refreshIfStale darf ihn nicht
        // aufrufen, weil noch frisch.
        let brokenSync = SnapshotSync(
            container: container,
            loader: { throw SnapshotSyncError.badResponse(-999) },
            staleAfter: 3600
        )
        try await brokenSync.refreshIfStale() // soll *nicht* werfen
    }

    // MARK: - Fixtures

    nonisolated(unsafe) static let firstRun: Data = .init(#"""
    {
      "generatedAt": "2026-05-08T20:48:48.795Z",
      "count": 2,
      "quotes": [
        { "slug": "spitteler-x", "text": "A",
          "authorSlug": "spitteler", "authorName": "Carl Spitteler",
          "language": "de", "themeSlugs": ["lebenskunst"],
          "regionSlugs": ["schweiz"] },
        { "slug": "keller-x", "text": "B",
          "authorSlug": "keller", "authorName": "Gottfried Keller",
          "language": "de", "themeSlugs": [],
          "regionSlugs": ["zuerich","schweiz"] }
      ]
    }
    """#.utf8)

    nonisolated(unsafe) static let secondRun: Data = .init(#"""
    {
      "generatedAt": "2026-05-09T00:00:00.000Z",
      "count": 2,
      "quotes": [
        { "slug": "spitteler-x", "text": "A-updated",
          "authorSlug": "spitteler", "authorName": "Carl Spitteler",
          "language": "de", "themeSlugs": ["lebenskunst"],
          "regionSlugs": ["schweiz"] },
        { "slug": "neuere-x", "text": "C",
          "authorSlug": "neuere", "authorName": "Anon",
          "language": "de", "themeSlugs": ["philosophie"],
          "regionSlugs": [] }
      ]
    }
    """#.utf8)

    nonisolated(unsafe) static let smallPayload: Data = .init(#"""
    {"generatedAt":"2026-05-01T00:00:00.000Z","count":1,
    "quotes":[{"slug":"a","text":"A","authorSlug":null,
    "authorName":null,"language":"de","themeSlugs":[],"regionSlugs":[]}]}
    """#.utf8)
}