/**
 * Inbox-underlag lifecycle for booked bank transactions.
 *
 * An invoice_inbox_items row leaves the active inbox ("Att göra") only when a
 * journal entry consumes it: created_journal_entry_id (or
 * created_supplier_invoice_id) is what deriveInboxStatus and the count pills
 * read. Historically only categorizeTransactionCore stamped that column, so a
 * matched item whose transaction was booked through any OTHER path (the /book
 * route, bulk-book, link-to-existing-voucher, or an attach that landed after
 * booking) stayed "linked" forever, pointing at a transaction that had left
 * the transactions work list (the 2026-08-12 user report).
 *
 * This module is the single implementation all booking and attach paths share:
 *
 *  - resolveBookedJournalEntryIds: which verifikat anchors each transaction,
 *    covering both direct journal_entry_id and the bulk-book
 *    transaction_voucher_links shape (see lib/transactions/is-booked.ts for
 *    why the column alone is not "booked").
 *  - propagateUnderlagForBookedTransaction: link matched items' documents to
 *    the verifikat (BFL 5 kap 6 §: the verifikation must reference its
 *    underlag) and stamp created_journal_entry_id.
 *  - completeInboxItemsForBookedTransaction: the attach-time entry point that
 *    resolves first and propagates only when the transaction is booked.
 *
 * Everything here is best-effort by contract: the verifikat is already posted
 * when these run, so a failure is logged and repaired by re-running, never
 * allowed to roll back a compliant booking. Note that
 * invoice_inbox_items.created_journal_entry_id is UNIQUE (migration
 * 20260515090000): when several items share one samlingsverifikat only the
 * first stamp can land, so the stamp is a fast path, not the source of truth:
 * the inbox list ALSO derives "booked" from the matched transaction's state
 * via resolveBookedJournalEntryIds (GET /items enrichment).
 */
import type { SupabaseClient } from '@supabase/supabase-js'
import { linkToJournalEntry } from '@/lib/core/documents/document-service'
import { createLogger } from '@/lib/logger'

const log = createLogger('transactions/inbox-underlag')

/** Postgres unique_violation: a sibling item already claimed this verifikat. */
const UNIQUE_VIOLATION = '23505'

/**
 * Map each booked transaction id to the journal entry that anchors it:
 * transactions.journal_entry_id first, then transaction_voucher_links
 * (the N-tx-to-1-JE bulk-book shape). Unbooked transactions are absent
 * from the returned map.
 *
 * The multi-allocation payment shape (invoice_payments /
 * supplier_invoice_payments) is deliberately not resolved here: those flows
 * consume inbox items through their own supplier-invoice lifecycle
 * (created_supplier_invoice_id), not through this one.
 */
export async function resolveBookedJournalEntryIds(
  supabase: SupabaseClient,
  companyId: string,
  txIds: string[],
): Promise<Map<string, string>> {
  const map = new Map<string, string>()
  if (txIds.length === 0) return map

  const { data: txs, error: txError } = await supabase
    .from('transactions')
    .select('id, journal_entry_id')
    .in('id', txIds)
    .eq('company_id', companyId)
  if (txError) {
    log.error('Failed to resolve transactions for booked-entry lookup', {
      company_id: companyId,
      error: txError.message,
    })
    return map
  }
  const unbooked: string[] = []
  for (const tx of (txs ?? []) as Array<{ id: string; journal_entry_id: string | null }>) {
    if (tx.journal_entry_id) map.set(tx.id, tx.journal_entry_id)
    else unbooked.push(tx.id)
  }
  if (unbooked.length === 0) return map

  const voucherLinked = await resolveVoucherLinkedEntryIds(supabase, companyId, unbooked)
  for (const [txId, journalEntryId] of voucherLinked) {
    if (!map.has(txId)) map.set(txId, journalEntryId)
  }
  return map
}

/**
 * The transaction_voucher_links leg of the resolution alone: for callers that
 * already hold transactions.journal_entry_id and only need the bulk-book
 * fallback.
 */
export async function resolveVoucherLinkedEntryIds(
  supabase: SupabaseClient,
  companyId: string,
  txIds: string[],
): Promise<Map<string, string>> {
  const map = new Map<string, string>()
  if (txIds.length === 0) return map
  const { data: links, error: linkError } = await supabase
    .from('transaction_voucher_links')
    .select('transaction_id, journal_entry_id')
    .in('transaction_id', txIds)
    .eq('company_id', companyId)
  if (linkError) {
    log.error('Failed to resolve voucher links for booked-entry lookup', {
      company_id: companyId,
      error: linkError.message,
    })
    return map
  }
  for (const link of (links ?? []) as Array<{ transaction_id: string; journal_entry_id: string }>) {
    if (!map.has(link.transaction_id)) map.set(link.transaction_id, link.journal_entry_id)
  }
  return map
}

/**
 * Propagate the underlag from matched invoice-inbox items onto the verifikat
 * that booked their transaction. Without this, BFL 7 kap is violated: a
 * verifikation exists with no underlag attached even though the user
 * explicitly linked an inbox item (with a document) to this transaction. We:
 *   1. find the inbox item(s) where matched_transaction_id = txId that no
 *      journal entry or supplier invoice has consumed yet
 *   2. for each item with a document_id, set
 *      document_attachments.journal_entry_id = journalEntryId, skipped when
 *      the document already points at a verifikat: a same-value rewrite would
 *      trip the period-lock trigger, and a different verifikat's underlag is
 *      never stolen
 *   3. stamp invoice_inbox_items.created_journal_entry_id so the inbox row
 *      visibly moves to "Bokförda" and shows "Öppna verifikation"
 * Errors are logged but never fail the caller: the verifikation itself is
 * already posted, and the link can be repaired by re-running this step.
 */
export async function propagateUnderlagForBookedTransaction(
  supabase: SupabaseClient,
  companyId: string,
  txId: string,
  journalEntryId: string,
): Promise<void> {
  try {
    const { data: matchedInboxItems } = await supabase
      .from('invoice_inbox_items')
      .select('id, document_id')
      .eq('company_id', companyId)
      .eq('matched_transaction_id', txId)
      .is('created_journal_entry_id', null)
      .is('created_supplier_invoice_id', null)
    for (const inbox of (matchedInboxItems ?? []) as Array<{
      id: string
      document_id: string | null
    }>) {
      // Whether this item's underlag actually references a verifikat. The
      // stamp below is conditional on it: stamping after a FAILED document
      // link would hide the item from every future run of this same query
      // (.is('created_journal_entry_id', null)), making the promised
      // "repaired by re-running" impossible and leaving a posted
      // verifikation with no underlag reference (BFL 5 kap 6-7 §) that
      // nothing surfaces anymore.
      let underlagSettled = true
      if (inbox.document_id) {
        const { data: doc } = await supabase
          .from('document_attachments')
          .select('journal_entry_id')
          .eq('id', inbox.document_id)
          .eq('company_id', companyId)
          .maybeSingle()
        const currentDocEntryId = (doc?.journal_entry_id as string | null) ?? null
        if (currentDocEntryId === null) {
          try {
            await linkToJournalEntry(supabase, companyId, inbox.document_id, journalEntryId)
          } catch (err) {
            underlagSettled = false
            log.error('Failed to link inbox document to journal entry', {
              inbox_item_id: inbox.id,
              document_id: inbox.document_id,
              journal_entry_id: journalEntryId,
              error: err instanceof Error ? err.message : String(err),
            })
          }
        } else if (currentDocEntryId !== journalEntryId) {
          // Anchored to another verifikat: preserved, never stolen. But the
          // verifikat that booked THIS transaction then has no underlag
          // reference from this item, so it must NOT be stamped consumed:
          // stamping would hide the very signal that the mismatch needs a
          // human (BFL 5 kap 6-7 §).
          underlagSettled = false
          log.warn('Inbox document already anchored to another verifikat; leaving it', {
            inbox_item_id: inbox.id,
            document_id: inbox.document_id,
            document_journal_entry_id: currentDocEntryId,
            journal_entry_id: journalEntryId,
          })
        }
      }
      if (!underlagSettled) continue
      // CAS on the null predicate so a concurrent stamp stays a no-op, and
      // unique_violation tolerated: on a samlingsverifikat only one item can
      // hold the UNIQUE created_journal_entry_id, and the inbox list derives
      // "booked" from the transaction's state for the rest.
      const { error: stampError } = await supabase
        .from('invoice_inbox_items')
        .update({ created_journal_entry_id: journalEntryId })
        .eq('id', inbox.id)
        .eq('company_id', companyId)
        .is('created_journal_entry_id', null)
      if (stampError && stampError.code !== UNIQUE_VIOLATION) {
        log.error('Failed to stamp inbox item created_journal_entry_id', {
          inbox_item_id: inbox.id,
          journal_entry_id: journalEntryId,
          error: stampError.message,
        })
      }
    }
  } catch (err) {
    log.error('Failed to propagate underlag from matched inbox items', err)
  }
}

/**
 * Attach-time entry point: when a document lands on (or an item is matched to)
 * a transaction that is ALREADY booked, resolve the anchoring verifikat and
 * complete the matched inbox items against it. No-op for unbooked
 * transactions: the booking paths call propagateUnderlagForBookedTransaction
 * themselves when the verifikat is created later.
 *
 * Callers that already read transactions.journal_entry_id pass it via
 * `directJournalEntryId` (null meaning "the column is null") to skip the
 * redundant transaction fetch; the voucher-link fallback still runs then.
 *
 * Returns the resolved journal entry id, or null when the transaction is not
 * booked.
 */
export async function completeInboxItemsForBookedTransaction(
  supabase: SupabaseClient,
  companyId: string,
  txId: string,
  opts?: { directJournalEntryId: string | null },
): Promise<string | null> {
  let journalEntryId: string | null
  if (opts) {
    journalEntryId =
      opts.directJournalEntryId ??
      (await resolveVoucherLinkedEntryIds(supabase, companyId, [txId])).get(txId) ??
      null
  } else {
    journalEntryId =
      (await resolveBookedJournalEntryIds(supabase, companyId, [txId])).get(txId) ?? null
  }
  if (!journalEntryId) return null
  await propagateUnderlagForBookedTransaction(supabase, companyId, txId, journalEntryId)
  return journalEntryId
}