// AsyncCallableTests.swift
// Covers the GIO async pattern binding: `planAsyncPairs` recognizing a
// `*_async`/`*_finish` pair and `renderAsyncMethod` emitting the paired
// Swift `async` method. Mirrors `CallbackGenerationTests.swift`'s style —
// exercising the planner through its public entry points and the renderer
// through `renderModule`'s public file output.

import Testing

@testable import GObjectGeneratorCore

@Suite("GIO async pattern")
struct AsyncCallableTests {

    // MARK: - Fixture

    /// A minimal `Gio`-module fixture: an `AsyncResult` class, a `Widget`
    /// class with one properly-shaped `foo_async`/`foo_finish` pair, and
    /// the `Gio.AsyncReadyCallback` callback type the pair's starter uses.
    /// Modeled entirely inside "Gio" itself (rather than a separate
    /// dependent module) so rule 6 (`currentModule == "Gio"`) is satisfied
    /// trivially, keeping the fixture minimal.
    func makeFooAsyncClass(includeFinish: Bool = true) -> Class {
        var methods = [
            Method(
                name: "foo_async", cIdentifier: "g_widget_foo_async",
                parameters: [
                    Parameter(name: "self", type: .typeRef("Widget"), isInstanceParameter: true),
                    Parameter(name: "callback", type: .typeRef("AsyncReadyCallback", namespace: "Gio"),
                             cType: "GAsyncReadyCallback", isNullable: true),
                    Parameter(name: "user_data", type: .pointer, cType: "gpointer", isNullable: true),
                ],
                returnValue: ReturnValue()
            ),
        ]
        if includeFinish {
            methods.append(Method(
                name: "foo_finish", cIdentifier: "g_widget_foo_finish",
                parameters: [
                    Parameter(name: "self", type: .typeRef("Widget"), isInstanceParameter: true),
                    Parameter(name: "result", type: .typeRef("AsyncResult", namespace: "Gio"), cType: "GAsyncResult*"),
                ],
                returnValue: ReturnValue(type: .boolean),
                throwsGError: true
            ))
        }
        return Class(name: "Widget", cType: "GWidget", parent: nil,
                     getTypeFunction: "g_widget_get_type", methods: methods)
    }

    func makeContext(includeFinish: Bool = true) -> (context: MapContext, klass: Class) {
        let klass = makeFooAsyncClass(includeFinish: includeFinish)
        let gio = Repository(namespaces: [
            Namespace(
                name: "Gio", version: "2.0",
                classes: [
                    Class(name: "AsyncResult", cType: "GAsyncResult", parent: nil,
                          getTypeFunction: "g_async_result_get_type"),
                    klass,
                ],
                callbacks: [Callback(
                    name: "AsyncReadyCallback", cType: "GAsyncReadyCallback",
                    parameters: [
                        Parameter(name: "source_object", type: .pointer, cType: "gpointer", isNullable: true),
                        Parameter(name: "res", type: .typeRef("AsyncResult"), cType: "GAsyncResult*"),
                        Parameter(name: "data", type: .pointer, cType: "gpointer", isNullable: true),
                    ]
                )]
            )
        ])
        let registry = TypeRegistry(repositories: ["Gio": gio])
        let context = MapContext(registry: registry, currentModule: "Gio", currentNamespace: "Gio")
        return (context, klass)
    }

    // MARK: - Recognizer

    @Test("A parsed foo_async + foo_finish pair produces one AsyncCallablePlan, and the starter's asyncRole parameters are the last two")
    func fooAsyncFooFinishProducesOnePair() throws {
        let (context, klass) = makeContext()
        let (plan, memberSkips) = planClass(klass, context: context)

        #expect(plan.asyncMethods.count == 1)
        let pair = try #require(plan.asyncMethods.first)
        #expect(pair.starter.name == "fooAsync")
        #expect(pair.finish.name == "fooFinish")

        // The starter's Swift-facing signature carries no callback/user-data
        // parameters — only the async-role pair, trailing.
        let realParams = pair.starter.parameters.filter { !$0.isInstanceParameter }
        #expect(realParams.count == 2)
        #expect(realParams[0].asyncRole == .callback)
        #expect(realParams[1].asyncRole == .userData)

        // No callable reaches methodPlans still skipped for the callback param.
        #expect(!plan.methods.contains { $0.name == "fooAsync" })
        #expect(plan.methods.contains { $0.name == "fooFinish" })

        // The stale D4.3 skip for the paired starter was dropped.
        #expect(!memberSkips.contains { $0.cIdentifier == "g_widget_foo_async" })
    }

    @Test("foo_async with no foo_finish produces no pair and keeps its callbackWithoutUserData skip")
    func fooAsyncWithoutFinishStaysSkipped() throws {
        let (context, klass) = makeContext(includeFinish: false)
        let (plan, memberSkips) = planClass(klass, context: context)

        #expect(plan.asyncMethods.isEmpty)
        #expect(!plan.methods.contains { $0.name == "fooAsync" })
        let skip = try #require(memberSkips.first { $0.cIdentifier == "g_widget_foo_async" })
        #expect(skip.reason == .callbackWithoutUserData)
    }

    // MARK: - Renderer

    @Test("renderAsyncMethod output contains async throws, _sgtkAwaitAsyncReady, defer g_object_unref, and AsyncResultRef(retaining:)")
    func renderedAsyncMethodContainsExpectedFragments() throws {
        let (context, klass) = makeContext()
        let (plan, _) = planClass(klass, context: context)
        let module = ModulePlan(module: "Gio", types: [.class(plan)], skips: [], coverage: CoverageStats())
        let files = renderModule(module)
        let source = try #require(files["Widget.swift"])

        #expect(source.contains("public func fooAsync(") )
        #expect(source.contains(") async throws"))
        #expect(source.contains("_sgtkAwaitAsyncReady"))
        #expect(source.contains("defer { g_object_unref("))
        #expect(source.contains("AsyncResultRef(retaining:"))
        #expect(source.contains("try fooFinish(result:"))
    }

    @Test("swiftSignature for a starter omits the callback and user-data parameters")
    func starterSignatureOmitsAsyncRoleParameters() throws {
        let (context, klass) = makeContext()
        let (plan, _) = planClass(klass, context: context)
        let module = ModulePlan(module: "Gio", types: [.class(plan)], skips: [], coverage: CoverageStats())
        let files = renderModule(module)
        let source = try #require(files["Widget.swift"])

        // The starter takes no real parameters beyond the trailing async
        // pair, so its emitted signature is empty parens.
        #expect(source.contains("public func fooAsync() async throws"))
        #expect(!source.contains("callback:"))
        #expect(!source.contains("userData:"))
    }
}