# module_buchungen.R

buchungenUI <- function(id) {
  ns <- NS(id)
  tagList(
    h3("Hauptbuchungen"),
    reactableOutput(ns("buchungen_table")),
    hr(),
    h3("Details / Gegenbuchungen"),
    reactableOutput(ns("details_table")),
    br(),
    actionBttn(ns("add_trans"), "Transaktion hinzu", size = "sm", style = "material-flat", color = "warning"),
    actionBttn(ns("del_trans"), "Transaktion Löschen", size = "sm", style = "material-flat", color = "danger"),
    actionBttn(ns("add_detail"), "Detail hinzu", size = "sm", style = "material-flat", color = "success"),
    
    # Das UI-Element des Moduls (auch wenn es leer ist)
    postingModuleUI(ns("posting_modal"))
  )
}

buchungenServer <- function(id, conn) {
  moduleServer(id, function(input, output, session) {
    ns <- session$ns 
    
    # Reactive States ----
    postings_data <- reactiveVal(read_buch_tabelle(conn))
    details_data  <- reactiveVal(NULL)
    selected_trans_id <- reactiveVal(NULL)
    current_main_idx <- reactiveVal(NULL)
    
    # Trigger-Objekt für das Modal: enthält post_id und einen Counter
    # Der Counter erzwingt eine Reaktion, auch wenn die gleiche ID zweimal geklickt wird
    modal_trigger <- reactiveVal(list(post_id = NULL, counter = 0))
    
    # --- MODUL-SERVER STARTEN (EINMALIG) ----
    update_db_trigger <- postingModuleServer("posting_modal", conn, selected_trans_id, modal_trigger)
    
    # Haupttabelle rendern ----
    output$buchungen_table <- renderReactable({
      req(postings_data())
      f_reactable(daten = postings_data(), coldefs = coldef_entries_tabelle, 
        selection = "single",
        defaultSelected = current_main_idx())
    })
    
    # Details laden wenn Zeile gewählt wird ----
    sel_details <- reactive(getReactableState("buchungen_table", "selected"))
    observeEvent(sel_details(), ignoreInit = T, {
      current_main_idx(getReactableState("buchungen_table", "selected"))
      t_id <- postings_data()[sel_details(), "entry_id"] %>% pull()
      selected_trans_id(t_id)
      details_data(read_buch_tabelle(conn, trans_id = t_id))
    })
    
    output$details_table <- renderReactable({
      req(details_data())
      f_reactable(details_data(), coldefs = coldef_entries_tabelle, selection = "single")
    })
    
    # Event: Detail hinzufügen (Neu) ----
    observeEvent(input$add_detail, {
      req(selected_trans_id())
      modal_trigger(list(post_id = NULL, counter = modal_trigger()$counter + 1))
    })
    
    # Event: Detail editieren (Klick auf Detail-Tabelle) ----
    sel_detail <- reactive(getReactableState("details_table", "selected"))
    observeEvent(sel_detail(), ignoreInit = T, {
      p_id <- details_data()$id[sel_detail()]
      modal_trigger(list(post_id = p_id, counter = modal_trigger()$counter + 1))
    })
    
    # --- DAS REAKTIVE UPDATE ----
    # Wenn das Modal sagt "Fertig", laden wir die Details neu
    observeEvent(update_db_trigger(), ignoreInit = TRUE, {
      req(selected_trans_id())
      # Tabellen-Daten neu aus DB ziehen
      details_data(read_buch_tabelle(conn, trans_id = selected_trans_id()))
      # Optional: Auch Haupttabelle erneuern, falls sich Summen geändert haben
      postings_data(read_buch_tabelle(conn))
    })
    
    #  'Neue Transaktion' Observer ----
    observeEvent(input$add_trans, {
      new_t_id <- max_id(conn, "entries") + 1
      
      # 1. Entry anlegen
      dbxInsert(conn, "entries", data.frame(id = new_t_id))
      
      # 2. Zwei Postings direkt vor-anlegen (z.B. mit Betrag 0)
      p_id1 <- max_id(conn, "postings") + 1
      p_id2 <- p_id1 + 1
      
      new_postings <- data.frame(
        id = c(p_id1, p_id2),
        entry_id = c(new_t_id, new_t_id),
        amount = c(0, 0),
        account_id = c(0, 0),
        valuta = c(Sys.Date(), Sys.Date())
        
      )
      dbxInsert(conn, "postings", new_postings)
      
      # 3. UI refreshen
      selected_trans_id(new_t_id)
      postings_data(read_buch_tabelle(conn))
      details_data(read_buch_tabelle(conn, trans_id = new_t_id))
    })
    
  })
}