import XCTest
@testable import ReynaCLIHostCore
import Foundation

// TDD for calendar.events.list and calendar.event.create – fake providers only, no live EventKit

final class CalendarEventsTests: XCTestCase {

    // MARK: - Helper types

    struct FakeCalendarListForSelection: CalendarListProviding {
        var calendars: [CalendarListItem]
        func listCalendars() throws -> [CalendarListItem] { calendars }
    }

    struct FakeEventsProvider: CalendarEventsListProviding {
        var events: [CalendarEventItem]
        var shouldThrow: CalendarProviderError? = nil

        func listEvents(start: Date, end: Date, calendarId: String?, calendarTitle: String?, limit: Int) throws -> [CalendarEventItem] {
            if let err = shouldThrow { throw err }
            var filtered = events
            if let cid = calendarId {
                filtered = filtered.filter { $0.calendar_id == cid }
            } else if let ctitle = calendarTitle {
                filtered = filtered.filter { $0.calendar_title == ctitle }
            }
            return filtered
        }
    }

    struct SelectingEventsProvider: CalendarEventsListProviding {
        var availableCalendars: [CalendarListItem]
        var events: [CalendarEventItem]

        func listEvents(start: Date, end: Date, calendarId: String?, calendarTitle: String?, limit: Int) throws -> [CalendarEventItem] {
            if let cid = calendarId {
                guard availableCalendars.contains(where: { $0.id == cid }) else {
                    throw CalendarProviderError.invalidRequest("Calendar not found: \(cid)")
                }
                return events.filter { $0.calendar_id == cid }.prefix(limit).map { $0 }
            }
            if let title = calendarTitle {
                let matched = availableCalendars.filter { $0.title == title }
                if matched.isEmpty {
                    throw CalendarProviderError.invalidRequest("Calendar not found: \(title)")
                }
                if matched.count > 1 {
                    throw CalendarProviderError.invalidRequest("Ambiguous calendar title: \(title) matches \(matched.count) calendars")
                }
                return events.filter { $0.calendar_title == title }.prefix(limit).map { $0 }
            }
            let sorted = events.sorted { $0.start < $1.start }
            return Array(sorted.prefix(limit))
        }
    }

    struct FakeCreateProvider: CalendarEventCreateProviding {
        var shouldThrow: CalendarProviderError? = nil
        var willReturn: CalendarEventItem

        func createEvent(title: String, start: Date, end: Date, allDay: Bool, notes: String?, location: String?, calendarId: String?, calendarTitle: String?) throws -> CalendarEventItem {
            if let err = shouldThrow { throw err }
            return willReturn
        }
    }

    struct SelectingCreateProvider: CalendarEventCreateProviding {
        var availableCalendars: [CalendarListItem]
        var writableIds: Set<String>
        var willReturn: CalendarEventItem

        func createEvent(title: String, start: Date, end: Date, allDay: Bool, notes: String?, location: String?, calendarId: String?, calendarTitle: String?) throws -> CalendarEventItem {
            if let cid = calendarId {
                guard let cal = availableCalendars.first(where: { $0.id == cid }) else {
                    throw CalendarProviderError.invalidRequest("Calendar not found: \(cid)")
                }
                guard writableIds.contains(cal.id) else {
                    throw CalendarProviderError.invalidRequest("Calendar is read-only: \(cal.title)")
                }
                return willReturn
            }
            if let t = calendarTitle {
                let matched = availableCalendars.filter { $0.title == t }
                if matched.isEmpty { throw CalendarProviderError.invalidRequest("Calendar not found: \(t)") }
                if matched.count > 1 { throw CalendarProviderError.invalidRequest("Ambiguous calendar title: \(t) matches \(matched.count) calendars") }
                guard writableIds.contains(matched[0].id) else {
                    throw CalendarProviderError.invalidRequest("Calendar is read-only: \(matched[0].title)")
                }
                return willReturn
            }
            throw CalendarProviderError.invalidRequest("Calendar must be specified by id or exact unique title")
        }
    }

    struct DeniedEventsProvider: CalendarEventsListProviding {
        func listEvents(start: Date, end: Date, calendarId: String?, calendarTitle: String?, limit: Int) throws -> [CalendarEventItem] {
            throw CalendarProviderError.permissionRequired
        }
    }

    struct FailEventsProvider: CalendarEventsListProviding {
        func listEvents(start: Date, end: Date, calendarId: String?, calendarTitle: String?, limit: Int) throws -> [CalendarEventItem] {
            throw CalendarProviderError.unavailable("disk fail")
        }
    }

    struct DeniedCreateProvider: CalendarEventCreateProviding {
        func createEvent(title: String, start: Date, end: Date, allDay: Bool, notes: String?, location: String?, calendarId: String?, calendarTitle: String?) throws -> CalendarEventItem {
            throw CalendarProviderError.permissionRequired
        }
    }

    struct MockAuthProvider: CalendarAuthorizationProviding {
        var status: CalendarAuthorizationStatus
        func authorizationStatus() -> CalendarAuthorizationStatus { status }
        func requestFullAccess() throws -> Bool { false }
    }

    final class CountingCreate: CalendarEventCreateProviding, @unchecked Sendable {
        var count = 0
        func createEvent(title: String, start: Date, end: Date, allDay: Bool, notes: String?, location: String?, calendarId: String?, calendarTitle: String?) throws -> CalendarEventItem {
            count += 1
            return CalendarEventItem(id: "sample", title: "Sample", start: "2026-01-01T10:00:00Z", end: "2026-01-01T11:00:00Z", all_day: false, calendar_id: "cal1", calendar_title: "Home", notes: nil, location: nil)
        }
    }

    func sampleEvent() -> CalendarEventItem {
        CalendarEventItem(id: "sample", title: "Sample", start: "2026-01-01T10:00:00Z", end: "2026-01-01T11:00:00Z", all_day: false, calendar_id: "cal1", calendar_title: "Home", notes: nil, location: nil)
    }

    // MARK: - List tests

    func testEventsListMissingStartReturnsInvalidRequest() {
        let req = Request(id: "e1", operation: "calendar.events.list", arguments: .object(["end": .string("2026-01-02T00:00:00Z")]))
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testEventsListInvalidISODate() {
        let args: JSONValue = .object(["start": .string("not-a-date"), "end": .string("2026-01-02T00:00:00Z")])
        let req = Request(id: "e2", operation: "calendar.events.list", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testEventsListStartAfterEnd() {
        let args: JSONValue = .object(["start": .string("2026-01-03T00:00:00Z"), "end": .string("2026-01-02T00:00:00Z")])
        let req = Request(id: "e3", operation: "calendar.events.list", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testEventsListLimitBounded() {
        let argsLow: JSONValue = .object(["start": .string("2026-01-01T00:00:00Z"), "end": .string("2026-01-02T00:00:00Z"), "limit": .number(0)])
        let reqLow = Request(id: "e4", operation: "calendar.events.list", arguments: argsLow)
        let respLow = dispatch(request: reqLow, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(respLow.ok)
        XCTAssertEqual(respLow.error?.code, "invalid_request")

        let argsHigh: JSONValue = .object(["start": .string("2026-01-01T00:00:00Z"), "end": .string("2026-01-02T00:00:00Z"), "limit": .number(251)])
        let reqHigh = Request(id: "e5", operation: "calendar.events.list", arguments: argsHigh)
        let respHigh = dispatch(request: reqHigh, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(respHigh.ok)
        XCTAssertEqual(respHigh.error?.code, "invalid_request")
    }

    func testEventsListSuccessSortedAndMinimalFields() {
        let ev1 = CalendarEventItem(id: "2", title: "B", start: "2026-01-01T11:00:00Z", end: "2026-01-01T12:00:00Z", all_day: false, calendar_id: "cal1", calendar_title: "Home", notes: "n2", location: "loc2")
        let ev2 = CalendarEventItem(id: "1", title: "A", start: "2026-01-01T10:00:00Z", end: "2026-01-01T11:00:00Z", all_day: false, calendar_id: "cal1", calendar_title: "Home", notes: nil, location: nil)
        let provider = FakeEventsProvider(events: [ev1, ev2])
        let args: JSONValue = .object(["start": .string("2026-01-01T00:00:00Z"), "end": .string("2026-01-02T00:00:00Z"), "limit": .number(10)])
        let req = Request(id: "e6", operation: "calendar.events.list", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: provider, createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertTrue(resp.ok)
        XCTAssertEqual(resp.result?.events?.count, 2)
        XCTAssertEqual(resp.result?.events?.first?.id, "1")
        let encoded = try! JSONEncoder().encode(resp)
        let obj = try! JSONSerialization.jsonObject(with: encoded) as! [String: Any]
        let result = obj["result"] as! [String: Any]
        let events = result["events"] as! [[String: Any]]
        for ev in events {
            XCTAssertNotNil(ev["id"])
            XCTAssertNotNil(ev["title"])
            XCTAssertNotNil(ev["start"])
            XCTAssertNotNil(ev["end"])
            XCTAssertNotNil(ev["calendar_id"])
            XCTAssertNotNil(ev["calendar_title"])
            let allowed = Set(["id","title","start","end","all_day","calendar_id","calendar_title","notes","location"])
            XCTAssertTrue(Set(ev.keys).isSubset(of: allowed), "Unexpected keys: \(ev.keys)")
        }
    }

    func testEventsListCalendarIdWinsOverTitle() {
        let calendars = [
            CalendarListItem(id: "id1", title: "Home", source: "iCloud", type: "caldav"),
            CalendarListItem(id: "id2", title: "Home", source: "Local", type: "local")
        ]
        let ev1 = CalendarEventItem(id: "e1", title: "T", start: "2026-01-01T10:00:00Z", end: "2026-01-01T11:00:00Z", all_day: false, calendar_id: "id1", calendar_title: "Home", notes: nil, location: nil)
        let ev2 = CalendarEventItem(id: "e2", title: "T", start: "2026-01-01T11:00:00Z", end: "2026-01-01T12:00:00Z", all_day: false, calendar_id: "id2", calendar_title: "Home", notes: nil, location: nil)
        let provider = SelectingEventsProvider(availableCalendars: calendars, events: [ev1, ev2])
        let args: JSONValue = .object([
            "start": .string("2026-01-01T00:00:00Z"),
            "end": .string("2026-01-02T00:00:00Z"),
            "calendar_id": .string("id1"),
            "calendar": .string("Home"),
            "limit": .number(10)
        ])
        let req = Request(id: "e7", operation: "calendar.events.list", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: calendars), eventsProvider: provider, createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertTrue(resp.ok)
        XCTAssertEqual(resp.result?.events?.count, 1)
        XCTAssertEqual(resp.result?.events?.first?.calendar_id, "id1")
    }

    func testEventsListUnknownCalendarFailsDeterministic() {
        let calendars = [CalendarListItem(id: "id1", title: "Home", source: "iCloud", type: "caldav")]
        let provider = SelectingEventsProvider(availableCalendars: calendars, events: [])
        let args: JSONValue = .object([
            "start": .string("2026-01-01T00:00:00Z"),
            "end": .string("2026-01-02T00:00:00Z"),
            "calendar": .string("Work")
        ])
        let req = Request(id: "e8", operation: "calendar.events.list", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: calendars), eventsProvider: provider, createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testEventsListAmbiguousTitleFails() {
        let calendars = [
            CalendarListItem(id: "id1", title: "Home", source: "iCloud", type: "caldav"),
            CalendarListItem(id: "id2", title: "Home", source: "Local", type: "local")
        ]
        let provider = SelectingEventsProvider(availableCalendars: calendars, events: [])
        let args: JSONValue = .object([
            "start": .string("2026-01-01T00:00:00Z"),
            "end": .string("2026-01-02T00:00:00Z"),
            "calendar": .string("Home")
        ])
        let req = Request(id: "e9", operation: "calendar.events.list", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: calendars), eventsProvider: provider, createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
        XCTAssertTrue(resp.error?.message.contains("Ambiguous") ?? false)
    }

    func testEventsListPermissionRequired() {
        let args: JSONValue = .object([
            "start": .string("2026-01-01T00:00:00Z"),
            "end": .string("2026-01-02T00:00:00Z")
        ])
        let req = Request(id: "e10", operation: "calendar.events.list", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: DeniedEventsProvider(), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "permission_required")
    }

    func testEventsListProviderFailureMapsToUnavailable() {
        let args: JSONValue = .object([
            "start": .string("2026-01-01T00:00:00Z"),
            "end": .string("2026-01-02T00:00:00Z")
        ])
        let req = Request(id: "e11", operation: "calendar.events.list", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FailEventsProvider(), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "calendar_unavailable")
    }

    // MARK: - Create tests

    func testCreateMissingTitleInvalid() {
        let args: JSONValue = .object([
            "start": .string("2026-01-01T10:00:00Z"),
            "end": .string("2026-01-01T11:00:00Z"),
            "calendar_id": .string("id1")
        ])
        let req = Request(id: "c1", operation: "calendar.event.create", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testCreateStartAfterEndInvalid() {
        let args: JSONValue = .object([
            "title": .string("Meeting"),
            "start": .string("2026-01-01T12:00:00Z"),
            "end": .string("2026-01-01T11:00:00Z"),
            "calendar_id": .string("id1")
        ])
        let req = Request(id: "c2", operation: "calendar.event.create", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testCreateInvalidISO() {
        let args: JSONValue = .object([
            "title": .string("Meeting"),
            "start": .string("bad-date"),
            "end": .string("2026-01-01T11:00:00Z"),
            "calendar_id": .string("id1")
        ])
        let req = Request(id: "c3", operation: "calendar.event.create", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: FakeCreateProvider(willReturn: sampleEvent()), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testCreateNoCalendarSpecifiedFailsNoDefault() {
        let args: JSONValue = .object([
            "title": .string("Meeting"),
            "start": .string("2026-01-01T10:00:00Z"),
            "end": .string("2026-01-01T11:00:00Z")
        ])
        let req = Request(id: "c4", operation: "calendar.event.create", arguments: args)
        let calendars = [CalendarListItem(id: "id1", title: "Home", source: "iCloud", type: "caldav")]
        let provider = SelectingCreateProvider(availableCalendars: calendars, writableIds: ["id1"], willReturn: sampleEvent())
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: calendars), eventsProvider: FakeEventsProvider(events: []), createProvider: provider, authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
        XCTAssertTrue(resp.error?.message.contains("must be specified") ?? false)
    }

    func testCreateUnknownCalendarFails() {
        let args: JSONValue = .object([
            "title": .string("Meeting"),
            "start": .string("2026-01-01T10:00:00Z"),
            "end": .string("2026-01-01T11:00:00Z"),
            "calendar": .string("Nonexistent")
        ])
        let req = Request(id: "c5", operation: "calendar.event.create", arguments: args)
        let calendars = [CalendarListItem(id: "id1", title: "Home", source: "iCloud", type: "caldav")]
        let provider = SelectingCreateProvider(availableCalendars: calendars, writableIds: ["id1"], willReturn: sampleEvent())
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: calendars), eventsProvider: FakeEventsProvider(events: []), createProvider: provider, authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testCreateAmbiguousTitleFails() {
        let args: JSONValue = .object([
            "title": .string("Meeting"),
            "start": .string("2026-01-01T10:00:00Z"),
            "end": .string("2026-01-01T11:00:00Z"),
            "calendar": .string("Home")
        ])
        let req = Request(id: "c6", operation: "calendar.event.create", arguments: args)
        let calendars = [
            CalendarListItem(id: "id1", title: "Home", source: "iCloud", type: "caldav"),
            CalendarListItem(id: "id2", title: "Home", source: "Local", type: "local")
        ]
        let provider = SelectingCreateProvider(availableCalendars: calendars, writableIds: ["id1","id2"], willReturn: sampleEvent())
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: calendars), eventsProvider: FakeEventsProvider(events: []), createProvider: provider, authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testCreateReadOnlyCalendarFails() {
        let args: JSONValue = .object([
            "title": .string("Meeting"),
            "start": .string("2026-01-01T10:00:00Z"),
            "end": .string("2026-01-01T11:00:00Z"),
            "calendar_id": .string("id1")
        ])
        let req = Request(id: "c7", operation: "calendar.event.create", arguments: args)
        let calendars = [CalendarListItem(id: "id1", title: "Birthdays", source: "iCloud", type: "birthday")]
        let provider = SelectingCreateProvider(availableCalendars: calendars, writableIds: [], willReturn: sampleEvent())
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: calendars), eventsProvider: FakeEventsProvider(events: []), createProvider: provider, authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "invalid_request")
    }

    func testCreateSuccessReturnsMetadata() {
        let args: JSONValue = .object([
            "title": .string("Meeting"),
            "start": .string("2026-01-01T10:00:00Z"),
            "end": .string("2026-01-01T11:00:00Z"),
            "calendar_id": .string("id1"),
            "notes": .string("bring docs"),
            "location": .string("Room 1")
        ])
        let req = Request(id: "c8", operation: "calendar.event.create", arguments: args)
        let created = CalendarEventItem(id: "new-id", title: "Meeting", start: "2026-01-01T10:00:00Z", end: "2026-01-01T11:00:00Z", all_day: false, calendar_id: "id1", calendar_title: "Home", notes: "bring docs", location: "Room 1")
        let provider = FakeCreateProvider(willReturn: created)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: provider, authProvider: MockAuthProvider(status: .authorized))
        XCTAssertTrue(resp.ok)
        XCTAssertEqual(resp.result?.event?.id, "new-id")
        XCTAssertEqual(resp.result?.event?.calendar_id, "id1")
        XCTAssertEqual(resp.result?.operation, "calendar.event.create")
    }

    func testCreatePermissionRequired() {
        let args: JSONValue = .object([
            "title": .string("Meeting"),
            "start": .string("2026-01-01T10:00:00Z"),
            "end": .string("2026-01-01T11:00:00Z"),
            "calendar_id": .string("id1")
        ])
        let req = Request(id: "c9", operation: "calendar.event.create", arguments: args)
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: DeniedCreateProvider(), authProvider: MockAuthProvider(status: .authorized))
        XCTAssertFalse(resp.ok)
        XCTAssertEqual(resp.error?.code, "permission_required")
    }

    func testListDoesNotTriggerCreate() {
        let args: JSONValue = .object([
            "start": .string("2026-01-01T00:00:00Z"),
            "end": .string("2026-01-02T00:00:00Z")
        ])
        let req = Request(id: "iso", operation: "calendar.events.list", arguments: args)
        let counter = CountingCreate()
        let resp = dispatch(request: req, calendarProvider: FakeCalendarListForSelection(calendars: []), eventsProvider: FakeEventsProvider(events: []), createProvider: counter, authProvider: MockAuthProvider(status: .authorized))
        XCTAssertTrue(resp.ok)
        XCTAssertEqual(counter.count, 0, "list must not trigger create")
    }
}