//
//  AccountManager.swift
//  meterios
//
//  (c) 2025 Martin "maride" Dessauer
//

import Foundation
import SwiftUI

/// **AccountManager** stores connection details and the corresponding client
class AccountManager: ObservableObject {
    // default contains a ready-to-use instance of AccountManager, read from AppStorage
    static public var `default` = AccountManager()

    // accounts holds all saved accounts
    @Published private(set) var Accounts: Array<AccountManagerEntry> = []

    // init creates a new AccountManager, reading saved account data from AppStorage
    init() {
        self.Accounts = AccountManager.readFromRaw()
    }

    // readFromRaw reads the current accounts from the stored data and transforms it to a handy Account Array
    static private func readFromRaw() -> Array<AccountManagerEntry> {
        @AppStorage("accounts") var rawAccs = Data()
        do {
            let simpleAccs = try JSONDecoder().decode([Account].self, from: rawAccs)
            let richAccs = simpleAccs.map({ AccountManagerEntry($0) })
            return richAccs
        } catch {
            print("Error parsing stored accounts from JSON: \(error)")
            return []
        }
    }

    // writeToRaw writes the current account data to the AppStorage
    private func writeToRaw() {
        @AppStorage("accounts") var rawAccs = Data()
        do {
            let simpleAccs = Accounts.map({ $0.GetAccount() })
            rawAccs = try JSONEncoder().encode(simpleAccs)
        } catch {
            print("Error writing current accounts to JSON: \(error)")
        }
    }

    // CurrentAccount returns the currently selected account if there is one
    func CurrentAccount() -> AccountManagerEntry? {
        if self.Accounts.count > 0 {
            return self.Accounts.first
        }
        return nil
    }

    // AddAccount adds the given account if it doesn't exist yet
    func AddAccount(_ account: Account) {
        if IndexOfAccount(account) == nil {
            Accounts.append(AccountManagerEntry(account))
            writeToRaw()
        }
    }

    // IndexOfAccount returns the index of the specified account identified by address and user ID
    func IndexOfAccount(_ account: Account) -> Int? {
        return Accounts.firstIndex(where: {
            $0.GetAccount().GetAddress() == account.GetAddress() &&
            $0.GetAccount().GetUserID() == account.GetUserID()
        })
    }

    // RemoveAccount removes the account specified by address and user ID of the given Account, if present
    func RemoveAccount(_ account: Account) {
        if IndexOfAccount(account) != nil {
            Accounts.remove(at: IndexOfAccount(account)!)
            writeToRaw()
        }
    }

    // RemoveAccount removes the account specified by address and user ID of the given AccountManagerEntry, if present
    func RemoveAccount(_ account: AccountManagerEntry) {
        RemoveAccount(account.GetAccount())
    }
}