import XCTest
@testable import LCFeatureControl

/// Exact evaluate-response shape from Atomenta's `docs/feature-control/EXTERNAL_CLIENTS.md` §3.
private let evaluateResponseFixture = """
{
  "error": false,
  "code": "FEATURE_CONTROL_EVALUATED",
  "result": {
    "evaluatedAt": "2026-04-16T12:00:00.000Z",
    "configVersion": 7,
    "flags": {
      "fc.checkout_v2": {
        "enabled": true,
        "variant": "on",
        "payload": null,
        "reason": "rollout"
      },
      "fc.search_ranking_v3": {
        "enabled": false,
        "variant": "off",
        "payload": null,
        "reason": "default"
      }
    }
  }
}
"""

final class FeatureControlModelsTests: XCTestCase {

    func testFlagDecodesFromEvaluateResponseFixture() throws {
        let data = Data(evaluateResponseFixture.utf8)
        let envelope = try JSONDecoder().decode(FeatureControlEvaluateEnvelope.self, from: data)

        XCTAssertFalse(envelope.error)
        XCTAssertEqual(envelope.result.configVersion, 7)

        let checkout = try XCTUnwrap(envelope.result.flags["fc.checkout_v2"])
        XCTAssertTrue(checkout.enabled)
        XCTAssertEqual(checkout.variant, "on")
        XCTAssertNil(checkout.payload)
        XCTAssertEqual(checkout.reason, "rollout")

        let ranking = try XCTUnwrap(envelope.result.flags["fc.search_ranking_v3"])
        XCTAssertFalse(ranking.enabled)
    }

    func testEvaluatedAtParsesFractionalSecondsISO8601() throws {
        let data = Data(evaluateResponseFixture.utf8)
        let envelope = try JSONDecoder().decode(FeatureControlEvaluateEnvelope.self, from: data)

        var calendar = Calendar(identifier: .gregorian)
        calendar.timeZone = TimeZone(identifier: "UTC")!
        let components = calendar.dateComponents([.year, .month, .day, .hour, .minute, .second],
                                                  from: envelope.result.evaluatedAt)
        XCTAssertEqual(components.year, 2026)
        XCTAssertEqual(components.month, 4)
        XCTAssertEqual(components.day, 16)
        XCTAssertEqual(components.hour, 12)
    }

    func testContextEncodesExactOpenAPIShape() throws {
        let context = FeatureControlContext(subjectType: .customer, subjectId: "cust_123",
                                            storeId: "store_001", platform: "ios",
                                            appVersion: "2.3.1",
                                            attributes: ["city": "Belo Horizonte"])
        let data = try JSONEncoder().encode(context)
        let object = try XCTUnwrap(try JSONSerialization.jsonObject(with: data) as? [String: Any])

        XCTAssertEqual(object["subjectType"] as? String, "customer")
        XCTAssertEqual(object["subjectId"] as? String, "cust_123")
        XCTAssertEqual(object["storeId"] as? String, "store_001")
        XCTAssertEqual(object["platform"] as? String, "ios")
        XCTAssertEqual(object["appVersion"] as? String, "2.3.1")
        let attributes = try XCTUnwrap(object["attributes"] as? [String: String])
        XCTAssertEqual(attributes["city"], "Belo Horizonte")
    }

    func testNotificationDecodesFromOpenAPIShape() throws {
        let json = """
        {
          "id": "n1",
          "title": "Manutenção",
          "body": "Janela de manutenção às 22h",
          "severity": "warning",
          "createdAt": "2026-04-16T12:00:00.000Z",
          "read": false,
          "ctaLabel": "Ver detalhes",
          "ctaUrl": "https://example.com"
        }
        """
        let notification = try JSONDecoder().decode(FeatureControlNotification.self, from: Data(json.utf8))
        XCTAssertEqual(notification.id, "n1")
        XCTAssertEqual(notification.severity, "warning")
        XCTAssertFalse(notification.read)
        XCTAssertEqual(notification.ctaLabel, "Ver detalhes")
    }

    func testNotificationDecodesWithoutOptionalCTAFields() throws {
        let json = """
        {
          "id": "n2",
          "title": "Info",
          "body": "Just FYI",
          "severity": "info",
          "createdAt": "2026-04-16T12:00:00Z",
          "read": true
        }
        """
        let notification = try JSONDecoder().decode(FeatureControlNotification.self, from: Data(json.utf8))
        XCTAssertNil(notification.ctaLabel)
        XCTAssertNil(notification.ctaUrl)
    }

    func testExposureEventEncodesExpectedShape() throws {
        let event = FeatureControlExposureEvent(featureKey: "fc.checkout_v2", variant: "on",
                                                subjectType: .customer, storeId: "store_001")
        let data = try JSONEncoder().encode(event)
        let object = try XCTUnwrap(try JSONSerialization.jsonObject(with: data) as? [String: Any])
        XCTAssertEqual(object["featureKey"] as? String, "fc.checkout_v2")
        XCTAssertEqual(object["subjectType"] as? String, "customer")
    }
}