import Foundation
import SwiftUI
import Combine
@MainActor
final class DashboardViewModel: ViewModel {

	@Published private(set) var prescriptions: [PrescriptionWithSchedulesResponse] = []
	@Published private(set) var medicationNames: [String: String] = [:]
	@Published private(set) var errorMessage: String?

	private let api: MedMapAPI

	init(api: MedMapAPI = MedMapAPI()) {
		self.api = api
		super.init()
	}

	var nextDose: DashboardDose? {
		scheduledDoses.first(where: { $0.time >= currentTime }) ?? scheduledDoses.first
	}

	var scheduledDoses: [DashboardDose] {
		prescriptions.flatMap { response in
			response.schedules.flatMap { schedule in
				schedule.timesOfDay.map { time in
					DashboardDose(
						time: time,
						title: medicationNames[response.medicationId] ?? "Medicacao prescrita",
						detail: response.prescription.instructions ?? doseDescription(schedule)
					)
				}
			}
		}
		.sorted { $0.time < $1.time }
	}

	func loadDashboard() async {
		guard !isLoading else { return }

		isLoading = true
		errorMessage = nil
		defer { isLoading = false }

		do {
			async let activePrescriptions = api.listMyActivePrescriptions()
			async let medications = api.listMedications()

			let (prescriptions, medicationResponse) = try await (activePrescriptions, medications)
			self.prescriptions = prescriptions
			medicationNames = Dictionary(
				uniqueKeysWithValues: medicationResponse.medications.map { ($0.medicationId, $0.name) }
			)
		} catch {
			errorMessage = "Nao foi possivel carregar a sua medicacao."
			fluxlog("Patient dashboard load failed: \(error.localizedDescription)")
		}
	}

	private var currentTime: String {
		let formatter = DateFormatter()
		formatter.locale = Locale(identifier: "en_US_POSIX")
		formatter.dateFormat = "HH:mm"
		return formatter.string(from: .now)
	}

	private func doseDescription(_ schedule: PrescriptionScheduleResponse) -> String {
		guard let amount = schedule.doseAmount else { return "Dose conforme prescricao" }
		let formattedAmount = amount.formatted(.number.precision(.fractionLength(0...2)))
		return schedule.doseUnit.map { "\(formattedAmount) \($0)" } ?? formattedAmount
	}
}

struct DashboardDose: Identifiable {
	let time: String
	let title: String
	let detail: String

	var id: String { "\(time)-\(title)-\(detail)" }
}
//  Created by RSA on 28/08/2026.
//