import Foundation

class Api {
    static let shared = Api()

    // ── DEV toggle: flip to false for production ──
    static let IS_DEV = true

    private static var BASE_URL: String {
        IS_DEV ? "https://dev.payfrit.com/api" : "https://biz.payfrit.com/api"
    }

    private let session: URLSession
    private var authToken: String?

    private init() {
        let config = URLSessionConfiguration.default
        config.timeoutIntervalForRequest = 30
        config.timeoutIntervalForResource = 30
        session = URLSession(configuration: config)
    }

    func setAuthToken(_ token: String?) {
        authToken = token
    }

    func getAuthToken() -> String? {
        return authToken
    }

    private func buildRequest(endpoint: String) -> URLRequest {
        let url = URL(string: "\(Api.BASE_URL)\(endpoint)")!
        var request = URLRequest(url: url)
        if let token = authToken {
            request.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
            request.setValue(token, forHTTPHeaderField: "X-User-Token")
        }
        return request
    }

    private func postRequest(endpoint: String, body: [String: Any], extraHeaders: [String: String] = [:]) async throws -> [String: Any] {
        var request = buildRequest(endpoint: endpoint)
        request.httpMethod = "POST"
        request.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
        request.httpBody = try JSONSerialization.data(withJSONObject: body)
        for (key, value) in extraHeaders {
            request.setValue(value, forHTTPHeaderField: key)
        }

        let (data, response) = try await session.data(for: request)
        guard let httpResponse = response as? HTTPURLResponse else {
            throw ApiException("Invalid response")
        }
        guard httpResponse.statusCode >= 200 && httpResponse.statusCode < 300 else {
            throw ApiException("Request failed: \(httpResponse.statusCode)")
        }
        guard !data.isEmpty else {
            throw ApiException("Empty response")
        }
        guard let json = try JSONSerialization.jsonObject(with: data) as? [String: Any] else {
            throw ApiException("Invalid JSON response")
        }
        return json
    }

    private func getRequest(endpoint: String) async throws -> [String: Any] {
        var request = buildRequest(endpoint: endpoint)
        request.httpMethod = "GET"

        let (data, response) = try await session.data(for: request)
        guard let httpResponse = response as? HTTPURLResponse else {
            throw ApiException("Invalid response")
        }
        guard httpResponse.statusCode >= 200 && httpResponse.statusCode < 300 else {
            throw ApiException("Request failed: \(httpResponse.statusCode)")
        }
        guard !data.isEmpty else {
            throw ApiException("Empty response")
        }
        guard let json = try JSONSerialization.jsonObject(with: data) as? [String: Any] else {
            throw ApiException("Invalid JSON response")
        }
        return json
    }

    // =========================================================================
    // AUTH
    // =========================================================================

    func sendLoginOtp(phone: String) async throws -> OtpResponse {
        let json = try await postRequest(endpoint: "/auth/loginOTP.cfm", body: ["Phone": phone])

        guard let uuid = (json["UUID"] as? String) ?? (json["uuid"] as? String), !uuid.isEmpty else {
            throw ApiException("Server error - please try again")
        }

        return OtpResponse(uuid: uuid)
    }

    func verifyLoginOtp(uuid: String, otp: String) async throws -> LoginResponse {
        let json = try await postRequest(endpoint: "/auth/verifyLoginOTP.cfm", body: [
            "UUID": uuid,
            "OTP": otp
        ])

        let ok = parseBool(json["OK"] ?? json["ok"])
        if !ok {
            let error = ((json["ERROR"] ?? json["error"]) as? String) ?? "Invalid code"
            throw ApiException(error)
        }

        return LoginResponse(
            userId: parseIntValue(json["UserID"] ?? json["USERID"]) ?? 0,
            token: ((json["Token"] ?? json["TOKEN"] ?? json["token"]) as? String) ?? "",
            userFirstName: ((json["UserFirstName"] ?? json["USERFIRSTNAME"]) as? String) ?? ""
        )
    }

    // =========================================================================
    // BUSINESSES
    // =========================================================================

    func listBusinesses() async throws -> [Business] {
        let json = try await postRequest(endpoint: "/businesses/list.cfm", body: [:])

        guard let businesses = (json["BUSINESSES"] ?? json["businesses"] ?? json["Items"] ?? json["ITEMS"]) as? [[String: Any]] else {
            return []
        }

        return businesses.compactMap { b in
            guard let businessId = parseIntValue(b["BusinessID"] ?? b["BUSINESSID"]) else {
                return nil
            }
            let name = ((b["BusinessName"] ?? b["BUSINESSNAME"] ?? b["Name"] ?? b["NAME"]) as? String) ?? ""
            let headerImageExtension = (b["HeaderImageExtension"] ?? b["HEADERIMAGEEXTENSION"]) as? String
            return Business(businessId: businessId, name: name, headerImageExtension: headerImageExtension)
        }
    }

    // =========================================================================
    // BEACONS
    // =========================================================================

    func listAllBeacons() async throws -> [String: Int] {
        let json = try await getRequest(endpoint: "/beacons/list_all.cfm")

        guard let items = (json["ITEMS"] ?? json["items"]) as? [[String: Any]] else {
            return [:]
        }

        var result: [String: Int] = [:]
        for item in items {
            guard let uuid = ((item["UUID"] ?? item["uuid"] ?? item["BeaconUUID"] ?? item["BEACONUUID"]) as? String)?
                .replacingOccurrences(of: "-", with: "").uppercased(),
                  let beaconId = parseIntValue(item["BeaconID"] ?? item["BEACONID"]) else {
                continue
            }
            result[uuid] = beaconId
        }
        return result
    }

    func lookupBeacons(uuids: [String]) async throws -> [BeaconLookupResult] {
        if uuids.isEmpty { return [] }

        let json = try await postRequest(endpoint: "/beacons/lookup.cfm", body: ["UUIDs": uuids])

        guard let beacons = (json["BEACONS"] ?? json["beacons"]) as? [[String: Any]] else {
            return []
        }

        return beacons.compactMap { b in
            guard let uuid = ((b["UUID"] ?? b["uuid"]) as? String)?
                .replacingOccurrences(of: "-", with: "").uppercased() else {
                return nil
            }
            return BeaconLookupResult(
                uuid: uuid,
                beaconId: parseIntValue(b["BeaconID"] ?? b["BEACONID"]) ?? 0,
                businessId: parseIntValue(b["BusinessID"] ?? b["BUSINESSID"]) ?? 0,
                businessName: ((b["BusinessName"] ?? b["BUSINESSNAME"]) as? String) ?? "",
                servicePointName: ((b["ServicePointName"] ?? b["SERVICEPOINTNAME"]) as? String) ?? "",
                beaconName: ((b["BeaconName"] ?? b["BEACONNAME"] ?? b["Name"] ?? b["NAME"]) as? String) ?? ""
            )
        }
    }

    func listBeacons(businessId: Int) async throws -> [BeaconInfo] {
        let json = try await postRequest(
            endpoint: "/beacons/list.cfm",
            body: ["BusinessID": businessId],
            extraHeaders: ["X-Business-Id": String(businessId)]
        )

        guard let beacons = (json["BEACONS"] ?? json["beacons"]) as? [[String: Any]] else {
            return []
        }

        return beacons.compactMap { b in
            let beaconId = parseIntValue(b["BeaconID"] ?? b["BEACONID"] ?? b["ID"]) ?? 0
            let name = ((b["Name"] ?? b["NAME"] ?? b["BeaconName"] ?? b["BEACONNAME"]) as? String) ?? ""
            let uuid = ((b["UUID"] ?? b["uuid"]) as? String)?
                .replacingOccurrences(of: "-", with: "").uppercased() ?? ""
            let isActive = parseBool(b["IsActive"] ?? b["ISACTIVE"] ?? true)
            return BeaconInfo(beaconId: beaconId, name: name, uuid: uuid, isActive: isActive)
        }
    }

    func saveBeacon(businessId: Int, name: String, uuid: String, macAddress: String? = nil) async throws -> SavedBeacon {
        var params: [String: Any] = [
            "BusinessID": businessId,
            "Name": name,
            "UUID": uuid
        ]
        if let mac = macAddress, !mac.isEmpty {
            params["MACAddress"] = mac
        }

        let json = try await postRequest(
            endpoint: "/beacons/save.cfm",
            body: params,
            extraHeaders: ["X-Business-Id": String(businessId)]
        )

        if !parseBool(json["OK"] ?? json["ok"]) {
            throw ApiException(((json["ERROR"] ?? json["error"]) as? String) ?? "Failed to save beacon")
        }

        let beacon = (json["BEACON"] ?? json["beacon"]) as? [String: Any]

        return SavedBeacon(
            beaconId: parseIntValue(beacon?["BeaconID"] ?? beacon?["BEACONID"] ?? beacon?["ID"]) ?? 0,
            name: (beacon?["Name"] ?? beacon?["NAME"]) as? String ?? name,
            uuid: uuid,
            macAddress: (beacon?["MACAddress"] ?? beacon?["MACADDRESS"]) as? String
        )
    }

    func lookupByMac(macAddress: String) async throws -> MacLookupResult? {
        let json = try await postRequest(endpoint: "/beacons/lookupByMac.cfm", body: ["MACAddress": macAddress])

        if !parseBool(json["OK"] ?? json["ok"]) {
            return nil
        }

        guard let beacon = (json["BEACON"] ?? json["beacon"]) as? [String: Any] else {
            return nil
        }

        return MacLookupResult(
            beaconId: parseIntValue(beacon["BeaconID"] ?? beacon["BEACONID"]) ?? 0,
            businessId: parseIntValue(beacon["BusinessID"] ?? beacon["BUSINESSID"]) ?? 0,
            businessName: ((beacon["BusinessName"] ?? beacon["BUSINESSNAME"]) as? String) ?? "",
            beaconName: ((beacon["BeaconName"] ?? beacon["BEACONNAME"]) as? String) ?? "",
            uuid: ((beacon["UUID"] ?? beacon["uuid"]) as? String) ?? "",
            macAddress: ((beacon["MACAddress"] ?? beacon["MACADDRESS"]) as? String) ?? "",
            servicePointName: ((beacon["ServicePointName"] ?? beacon["SERVICEPOINTNAME"]) as? String) ?? ""
        )
    }

    func wipeBeacon(businessId: Int, beaconId: Int) async throws -> Bool {
        let json = try await postRequest(
            endpoint: "/beacons/wipe.cfm",
            body: ["BusinessID": businessId, "BeaconID": beaconId],
            extraHeaders: ["X-Business-Id": String(businessId)]
        )

        if !parseBool(json["OK"] ?? json["ok"]) {
            let error = ((json["ERROR"] ?? json["error"]) as? String) ?? "Failed to wipe beacon"
            let message = (json["MESSAGE"] ?? json["message"]) as? String
            throw ApiException(message ?? error)
        }

        return true
    }

    // =========================================================================
    // HELPERS
    // =========================================================================

    private func parseBool(_ value: Any?) -> Bool {
        switch value {
        case nil:
            return false
        case let b as Bool:
            return b
        case let n as NSNumber:
            return n.intValue != 0
        case let s as String:
            return ["true", "1"].contains(s.lowercased())
        default:
            return false
        }
    }

    private func parseIntValue(_ value: Any?) -> Int? {
        if let n = value as? NSNumber {
            return n.intValue
        }
        if let s = value as? String, let i = Int(s) {
            return i
        }
        return nil
    }
}

struct ApiException: LocalizedError {
    let message: String
    init(_ message: String) { self.message = message }
    var errorDescription: String? { message }
}

// =========================================================================
// DATA MODELS
// =========================================================================

struct OtpResponse {
    let uuid: String
}

struct LoginResponse {
    let userId: Int
    let token: String
    let userFirstName: String
}

struct Business: Identifiable {
    var id: Int { businessId }
    let businessId: Int
    let name: String
    let headerImageExtension: String?
}

struct BeaconLookupResult {
    let uuid: String
    let beaconId: Int
    let businessId: Int
    let businessName: String
    let servicePointName: String
    let beaconName: String
}

struct BeaconInfo {
    let beaconId: Int
    let name: String
    let uuid: String
    let isActive: Bool
}

struct SavedBeacon {
    let beaconId: Int
    let name: String
    let uuid: String
    let macAddress: String?
}

struct MacLookupResult {
    let beaconId: Int
    let businessId: Int
    let businessName: String
    let beaconName: String
    let uuid: String
    let macAddress: String
    let servicePointName: String
}