package com.example.slflo

import java.math.BigDecimal

/**
 * What the connector needs from your ERP. Implement it with your ERP's own services; the
 * in-memory [InMemoryErp] lets the connector run end to end against the sandbox.
 */
interface ErpBooks {
    data class SalesLine(val lineNumber: Int, val item: String, val quantity: BigDecimal, val amount: BigDecimal)

    data class Customer(val account: String, val name: String, val priceList: String, val creditLimit: BigDecimal)

    data class Item(val number: String, val name: String, val unit: String, val price: BigDecimal)

    /** The sales order whose customer reference holds this Slflo order id (D365: `CustomersOrderReference`). */
    fun findSalesOrder(customerReference: String): String?

    /** Creates one sales order and returns its number. */
    fun createSalesOrder(customerReference: String, account: String, lines: List<SalesLine>): String

    /** Accounts the credit department put on hold: their orders are refused. */
    fun onHold(account: String): Boolean

    /** One journal per Slflo document version; posting the same version again returns the first. */
    fun postJournal(kind: String, sourceId: String, sourceVersion: Long, amount: String): String

    fun customers(): List<Customer>

    fun items(): List<Item>
}

class InMemoryErp(
    private val customers: List<ErpBooks.Customer> = emptyList(),
    private val items: List<ErpBooks.Item> = emptyList(),
    private val hold: Set<String> = emptySet(),
) : ErpBooks {
    private val orders = linkedMapOf<String, String>()
    private val journals = linkedMapOf<Triple<String, String, Long>, String>()

    override fun findSalesOrder(customerReference: String) = orders[customerReference]

    override fun createSalesOrder(customerReference: String, account: String, lines: List<ErpBooks.SalesLine>): String =
        "SO-%07d".format(orders.size + 1).also { orders[customerReference] = it }

    override fun onHold(account: String) = account in hold

    override fun postJournal(kind: String, sourceId: String, sourceVersion: Long, amount: String): String =
        journals.getOrPut(Triple(kind, sourceId, sourceVersion)) { "JRN-%06d".format(journals.size + 1) }

    override fun customers() = customers

    override fun items() = items
}