/**
 * Manual bank-statement FILE import (CAMT.052/053 from the online-banking export)
 * straight into iDempiere — for the period BEFORE EBICS was activated.
 *
 * Nuxt-only by design: no Laravel staging involved. Statements are created
 * Drafted with the same header/line shape the Laravel EBICS import writes
 * (`IdempiereBankStatementRepository::buildStatementPayload/buildLinePayload`),
 * so they show up in step ② "Abgleichen" like any other statement.
 *
 * DUPLICATE PROTECTION (the important part):
 *  - identity of a booking = the bank's `AcctSvcrRef`, which the EBICS import
 *    already stores as `C_BankStatementLine.EftTrxID`. An entry whose reference
 *    exists on ANY non-voided statement of the bank account is never written.
 *  - entries/lines without a reference fall back to date + amount + normalised
 *    memo, counted as a multiset (two identical bookings on one day stay two).
 *  - a day that already has a FOREIGN statement (EBICS / manual) is never
 *    touched, even if the file knows more lines (`conflict`, shown as warning).
 *  - a day whose statement was created by THIS importer and is still Drafted is
 *    resumed (`resume`): only the missing lines are added — so a half-failed
 *    import is repaired by simply uploading the same file again.
 *  - the plan is recomputed against live iDempiere data right before writing.
 */
import { string } from 'alga-js'
import { promises as fs } from 'node:fs'
import path from 'node:path'
import crypto from 'node:crypto'
import { fetchLinesForStatements } from '../bankReconciliation'
import { buildDailyStatements, centsToAmount } from './camt052Parser'
import type { CamtAccount, CamtEntry, CamtParseResult } from './camt052Parser'

export const IMPORT_REF_PREFIX = 'camt052-'
export const importRef = (iban: string, day: string): string => `${IMPORT_REF_PREFIX}${iban}-${day}`.slice(0, 60)

const STORE_DIR = path.join(process.cwd(), 'data', 'bank-file-import')
const TOKEN_TTL_MS = 24 * 60 * 60 * 1000
const CONTEXT_DAYS = 14

const shiftDay = (day: string, delta: number): string => {
  const date = new Date(day + 'T00:00:00Z')
  date.setUTCDate(date.getUTCDate() + delta)
  return date.toISOString().slice(0, 10)
}

const cut = (value: any, max: number): string => Array.from(String(value ?? '')).slice(0, max).join('')
const normIban = (value: any): string => String(value || '').replace(/\s+/g, '').toUpperCase()
const normMemo = (value: any): string => String(value || '').toUpperCase().replace(/[^A-Z0-9]/g, '').slice(0, 80)
const fallbackKey = (day: string, cents: number, memo: any): string => `${day}|${cents}|${normMemo(memo)}`

// ---------------------------------------------------------------------------
// Upload store (disk — PM2 runs several instances, memory would not be shared)

export const isValidToken = (token: any): boolean => /^[a-f0-9]{32}$/.test(String(token || ''))

const purgeExpired = async () => {
  try {
    const names = await fs.readdir(STORE_DIR)
    for (const name of names) {
      if (!isValidToken(name)) continue
      const stat = await fs.stat(path.join(STORE_DIR, name))
      if (Date.now() - stat.mtimeMs > TOKEN_TTL_MS) await fs.rm(path.join(STORE_DIR, name), { recursive: true, force: true })
    }
  } catch {}
}

export const saveUpload = async (parsed: CamtParseResult, uploads: { name: string; data: Uint8Array }[]): Promise<string> => {
  await purgeExpired()
  const token = crypto.randomBytes(16).toString('hex')
  const dir = path.join(STORE_DIR, token)
  await fs.mkdir(path.join(dir, 'raw'), { recursive: true })
  await fs.writeFile(path.join(dir, 'parsed.json'), JSON.stringify({ createdAt: new Date().toISOString(), parsed }))
  for (let i = 0; i < uploads.length; i++) {
    await fs.writeFile(path.join(dir, 'raw', `${i + 1}-${path.basename(uploads[i].name)}`), uploads[i].data)
  }
  return token
}

export const loadUpload = async (token: string): Promise<CamtParseResult | null> => {
  if (!isValidToken(token)) return null
  try {
    const raw = await fs.readFile(path.join(STORE_DIR, token, 'parsed.json'), 'utf-8')
    return JSON.parse(raw)?.parsed || null
  } catch {
    return null
  }
}

/** Keep the original bank files of an upload that actually wrote something. */
export const archiveUpload = async (token: string, iban: string) => {
  if (!isValidToken(token)) return
  try {
    const dir = path.join(STORE_DIR, token)
    try { await fs.access(path.join(dir, 'archived')); return } catch {}
    const target = path.join(STORE_DIR, 'archive', normIban(iban) || 'unknown')
    await fs.mkdir(target, { recursive: true })
    const stamp = new Date().toISOString().replace(/[:.]/g, '-')
    for (const name of await fs.readdir(path.join(dir, 'raw'))) {
      await fs.copyFile(path.join(dir, 'raw', name), path.join(target, `${stamp}-${name}`))
    }
    await fs.writeFile(path.join(dir, 'archived'), stamp)
  } catch (err: any) {
    console.warn('[BankFileImport] archive failed:', err?.message || err)
  }
}

// ---------------------------------------------------------------------------
// iDempiere reads

export interface ResolvedBankAccount { id: number; name: string; orgId: number; orgName: string }

/** C_BankAccount by IBAN — compared normalised (iDempiere may store it spaced). */
export const resolveBankAccount = async (event: any, token: any, iban: string): Promise<ResolvedBankAccount | null> => {
  const res: any = await event.context.fetch(
    `models/c_bankaccount?$filter=${string.urlEncode('IsActive eq true')}` +
    `&$select=Name,AccountNo,IBAN,AD_Org_ID&$top=200`,
    'GET', token, null
  )
  const wanted = normIban(iban)
  const hit = (res?.records || []).find((acc: any) => wanted && normIban(acc.IBAN) === wanted)
  if (!hit) return null
  return {
    id: Number(hit.id),
    name: hit.Name || hit.AccountNo || String(hit.id),
    orgId: Number(hit.AD_Org_ID?.id || 0),
    orgName: hit.AD_Org_ID?.identifier || ''
  }
}

interface ExistingStatement {
  id: number
  documentNo: string
  date: string
  docStatus: string
  eftReference: string
  beginningCents: number
  endingCents: number
  own: boolean
  maxLine: number
  lineCount: number
}

interface ExistingData {
  statements: ExistingStatement[]
  refs: Set<string>
  unreferenced: Map<string, number>
}

const loadExisting = async (event: any, token: any, bankAccountId: number, fromDay: string, toDay: string): Promise<ExistingData> => {
  const filter = `C_BankAccount_ID eq ${bankAccountId} and StatementDate ge ${fromDay} and StatementDate le ${toDay}`
  const statements: ExistingStatement[] = []
  const PAGE = 500
  for (let skip = 0; skip < 5000; skip += PAGE) {
    const res: any = await event.context.fetch(
      `models/c_bankstatement?$filter=${string.urlEncode(filter)}` +
      `&$select=DocumentNo,StatementDate,BeginningBalance,EndingBalance,DocStatus,EftStatementReference` +
      `&$orderby=${string.urlEncode('StatementDate asc,C_BankStatement_ID asc')}&$top=${PAGE}&$skip=${skip}`,
      'GET', token, null
    )
    const records = res?.records || []
    for (const rec of records) {
      const docStatus = rec.DocStatus?.id || rec.DocStatus || ''
      // Voided / reversed statements do not count as "already there".
      if (docStatus === 'VO' || docStatus === 'RE') continue
      const eftReference = String(rec.EftStatementReference || '')
      statements.push({
        id: Number(rec.id),
        documentNo: rec.DocumentNo || '',
        date: String(rec.StatementDate || '').slice(0, 10),
        docStatus,
        eftReference,
        beginningCents: Math.round(Number(rec.BeginningBalance || 0) * 100),
        endingCents: Math.round(Number(rec.EndingBalance || 0) * 100),
        own: eftReference.startsWith(IMPORT_REF_PREFIX),
        maxLine: 0,
        lineCount: 0
      })
    }
    if (records.length < PAGE) break
  }

  const refs = new Set<string>()
  const unreferenced = new Map<string, number>()
  if (statements.length) {
    const byId = new Map(statements.map((s) => [s.id, s]))
    const lines = await fetchLinesForStatements(
      event, token, statements.map((s) => s.id),
      '$select=C_BankStatement_ID,Line,StatementLineDate,StmtAmt,EftTrxID,EftMemo', 50000
    )
    for (const line of lines) {
      const statement = byId.get(Number(line.C_BankStatement_ID?.id))
      if (statement) {
        statement.lineCount++
        statement.maxLine = Math.max(statement.maxLine, Number(line.Line || 0))
      }
      const ref = String(line.EftTrxID || '').trim()
      if (ref) {
        refs.add(ref)
      } else {
        const key = fallbackKey(String(line.StatementLineDate || '').slice(0, 10), Math.round(Number(line.StmtAmt || 0) * 100), line.EftMemo)
        unreferenced.set(key, (unreferenced.get(key) || 0) + 1)
      }
    }
  }
  return { statements, refs, unreferenced }
}

// ---------------------------------------------------------------------------
// Plan

export type DayVerdict = 'would_create' | 'resume' | 'already_in_idempiere' | 'conflict' | 'no_lines'
export type LineVerdict = 'would_create' | 'already_in_idempiere' | 'skip_non_eur'

export interface PlannedLine {
  verdict: LineVerdict
  entry: CamtEntry
}

export interface PlannedDay {
  date: string
  verdict: DayVerdict
  openingCents: number | null
  closingCents: number | null
  netCents: number
  lines: PlannedLine[]
  existing: ExistingStatement[]
  counts: { wouldCreate: number; known: number; nonEur: number }
}

export interface AccountPlan {
  iban: string
  ownerName: string
  bankName: string
  bankAccount: ResolvedBankAccount | null
  days: PlannedDay[]
  balanceCheck: ReturnType<typeof buildDailyStatements>['check']
  chain: { ok: boolean; checks: { kind: string; day: string; statementDate: string; documentNo: string; expectedCents: number; computedCents: number; diffCents: number }[] }
  skipped: CamtAccount['skipped']
}

/**
 * Plan one account against LIVE iDempiere data. `onlyDays` restricts the
 * evaluation (import chunks) — balances still come from the whole file.
 */
export const planAccount = async (event: any, token: any, account: CamtAccount, onlyDays: string[] | null = null): Promise<AccountPlan> => {
  const bankAccount = await resolveBankAccount(event, token, account.iban)
  let { days, check } = buildDailyStatements(account)

  const wanted = onlyDays ? new Set(onlyDays) : null
  const scopeDays = days.filter((d) => !wanted || wanted.has(d.date))
  const plan: AccountPlan = {
    iban: account.iban,
    ownerName: account.ownerName,
    bankName: account.bankName,
    bankAccount,
    days: [],
    balanceCheck: check,
    chain: { ok: true, checks: [] },
    skipped: account.skipped
  }
  if (!bankAccount || !scopeDays.length) {
    plan.days = scopeDays.map((d) => ({
      date: d.date, verdict: 'no_lines' as DayVerdict, openingCents: d.openingCents, closingCents: d.closingCents, netCents: d.netCents,
      lines: d.entries.map((entry) => ({ verdict: 'would_create' as LineVerdict, entry })), existing: [],
      counts: { wouldCreate: 0, known: 0, nonEur: 0 }
    }))
    return plan
  }

  const fromDay = shiftDay(scopeDays[0].date, -CONTEXT_DAYS)
  const toDay = shiftDay(scopeDays[scopeDays.length - 1].date, CONTEXT_DAYS)
  const existing = await loadExisting(event, token, bankAccount.id, fromDay, toDay)

  // Files without any balance: anchor on the closing of the statement before.
  if (!check.anchored && days.length) {
    const before = existing.statements.filter((s) => s.date < days[0].date).pop()
    if (before) ({ days, check } = buildDailyStatements(account, before.endingCents))
    plan.balanceCheck = check
  }
  const dayByDate = new Map(days.map((d) => [d.date, d]))

  // Multiset of unreferenced existing lines — consumed as entries match.
  const unreferenced = new Map(existing.unreferenced)

  for (const scoped of scopeDays) {
    const day = dayByDate.get(scoped.date)!
    const sameDay = existing.statements.filter((s) => s.date === day.date)
    const lines: PlannedLine[] = []
    const counts = { wouldCreate: 0, known: 0, nonEur: 0 }

    for (const entry of day.entries) {
      let verdict: LineVerdict = 'would_create'
      if (entry.currency !== 'EUR') {
        verdict = 'skip_non_eur'
      } else if (entry.bankReference && existing.refs.has(cut(entry.bankReference, 40))) {
        verdict = 'already_in_idempiere'
      } else {
        const key = fallbackKey(entry.bookingDate, entry.amountCents, entry.remittanceInfo)
        const left = unreferenced.get(key) || 0
        if (left > 0) {
          unreferenced.set(key, left - 1)
          verdict = 'already_in_idempiere'
        }
      }
      if (verdict === 'would_create') counts.wouldCreate++
      else if (verdict === 'skip_non_eur') counts.nonEur++
      else counts.known++
      lines.push({ verdict, entry })
    }

    let verdict: DayVerdict
    if (counts.wouldCreate === 0) verdict = counts.known ? 'already_in_idempiere' : 'no_lines'
    else if (!sameDay.length) verdict = 'would_create'
    else if (sameDay.length === 1 && sameDay[0].own && sameDay[0].docStatus === 'DR' && sameDay[0].eftReference === importRef(account.iban, day.date)) verdict = 'resume'
    else verdict = 'conflict'

    plan.days.push({
      date: day.date, verdict, openingCents: day.openingCents, closingCents: day.closingCents, netCents: day.netCents,
      lines, existing: sameDay, counts
    })
  }

  // Balance chain vs. what iDempiere already holds (informational, never blocks):
  //  a) same-day statements must show the same opening/closing as the file
  //  b) the first existing statement after a NEW day must open with that day's closing
  const addCheck = (kind: string, day: string, statement: ExistingStatement, expectedCents: number, computedCents: number | null) => {
    if (computedCents === null) return
    const diffCents = computedCents - expectedCents
    if (diffCents !== 0) plan.chain.ok = false
    plan.chain.checks.push({ kind, day, statementDate: statement.date, documentNo: statement.documentNo, expectedCents, computedCents, diffCents })
  }
  for (const planned of plan.days) {
    if (planned.existing.length === 1 && planned.verdict === 'already_in_idempiere' && !planned.counts.nonEur) {
      // Reported only on a mismatch (one row per differing balance).
      const statement = planned.existing[0]
      if (statement.beginningCents !== planned.openingCents) addCheck('same_day_opening', planned.date, statement, statement.beginningCents, planned.openingCents)
      if (statement.endingCents !== planned.closingCents) addCheck('same_day_closing', planned.date, statement, statement.endingCents, planned.closingCents)
    }
  }
  const newDays = plan.days.filter((d) => d.verdict === 'would_create' || d.verdict === 'resume')
  for (const planned of newDays) {
    const nextFileDay = days.find((d) => d.date > planned.date)
    const nextStatement = existing.statements.find((s) => s.date > planned.date)
    // Only where the existing statement is the DIRECT successor of this new day.
    if (nextStatement && (!nextFileDay || nextStatement.date <= nextFileDay.date)) {
      addCheck('next_opening', planned.date, nextStatement, nextStatement.beginningCents, planned.closingCents)
    }
  }

  return plan
}

/** API shape of a plan (amounts as numbers, entries flattened). */
export const presentPlan = (plan: AccountPlan) => {
  const presentExisting = (s: ExistingStatement) => ({ id: s.id, documentNo: s.documentNo, docStatus: s.docStatus, own: s.own, lineCount: s.lineCount })
  const days = plan.days.map((d) => ({
    date: d.date,
    verdict: plan.bankAccount ? d.verdict : 'bank_account_missing',
    opening: centsToAmount(d.openingCents),
    closing: centsToAmount(d.closingCents),
    net: centsToAmount(d.netCents),
    counts: d.counts,
    existing: d.existing.map(presentExisting),
    lines: d.lines.map((l) => ({
      verdict: l.verdict,
      bookingDate: l.entry.bookingDate,
      valueDate: l.entry.valueDate,
      amount: l.entry.amount,
      currency: l.entry.currency,
      counterpart: l.entry.counterpartName || '',
      counterpartIban: l.entry.counterpartIban || '',
      remittanceInfo: l.entry.remittanceInfo || '',
      bankReference: l.entry.bankReference || '',
      batchCount: l.entry.batchCount
    }))
  }))
  const count = (verdict: string) => days.filter((d) => d.verdict === verdict).length
  const sum = (pick: (d: PlannedDay) => number) => plan.days.reduce((total, d) => total + pick(d), 0)
  const writable = plan.bankAccount ? plan.days.filter((d) => d.verdict === 'would_create' || d.verdict === 'resume') : []
  return {
    iban: plan.iban,
    ownerName: plan.ownerName,
    bankName: plan.bankName,
    bankAccount: plan.bankAccount,
    period: { from: days[0]?.date || null, to: days[days.length - 1]?.date || null },
    totals: {
      days: days.length,
      daysWouldCreate: count('would_create'),
      daysResume: count('resume'),
      daysKnown: count('already_in_idempiere'),
      daysConflict: count('conflict'),
      lines: sum((d) => d.lines.length),
      linesWouldCreate: writable.reduce((total, d) => total + d.counts.wouldCreate, 0),
      linesKnown: sum((d) => d.counts.known),
      linesNonEur: sum((d) => d.counts.nonEur),
      linesConflict: plan.days.filter((d) => d.verdict === 'conflict').reduce((total, d) => total + d.counts.wouldCreate, 0),
      pendingSkipped: plan.skipped.pending,
      duplicateInUpload: plan.skipped.duplicateInUpload
    },
    balanceCheck: {
      ok: plan.balanceCheck.ok,
      anchored: plan.balanceCheck.anchored,
      anchor: plan.balanceCheck.anchor ? { ...plan.balanceCheck.anchor, amount: centsToAmount(plan.balanceCheck.anchor.amountCents) } : null,
      diffs: plan.balanceCheck.diffs.map((d) => ({ type: d.type, date: d.date, file: d.file, expected: centsToAmount(d.expectedCents), computed: centsToAmount(d.computedCents), diff: centsToAmount(d.diffCents) }))
    },
    chain: {
      ok: plan.chain.ok,
      checks: plan.chain.checks.map((c) => ({ kind: c.kind, day: c.day, statementDate: c.statementDate, documentNo: c.documentNo, expected: centsToAmount(c.expectedCents), computed: centsToAmount(c.computedCents), diff: centsToAmount(c.diffCents) }))
    },
    writableDays: writable.map((d) => d.date),
    days
  }
}

// ---------------------------------------------------------------------------
// Write

const buildLinePayload = (entry: CamtEntry, statementId: number, orgId: number, lineNo: number) => {
  const description = [entry.counterpartName, entry.remittanceInfo].filter(Boolean).join(' | ')
  const payload: any = {
    AD_Org_ID: { id: orgId, tableName: 'AD_Org' },
    C_BankStatement_ID: { id: statementId, tableName: 'C_BankStatement' },
    line: lineNo,
    statementLineDate: entry.bookingDate,
    dateAcct: entry.bookingDate,
    stmtAmt: entry.amount,
    trxAmt: entry.amount,
    description: cut(description || entry.additionalInfo || 'Bank transaction', 255),
    eftPayee: cut(entry.counterpartName, 255),
    eftPayeeAccount: cut(entry.counterpartIban, 40),
    eftMemo: cut(entry.remittanceInfo, 2000)
  }
  if (entry.valueDate) payload.valutaDate = entry.valueDate
  const reference = entry.endToEndId || entry.bankReference
  if (reference) payload.referenceNo = cut(reference, 40)
  // The duplicate-detection key — same column the EBICS import fills.
  if (entry.bankReference) payload.eftTrxID = cut(entry.bankReference, 40)
  return payload
}

const isAuthError = (err: any): boolean => [401, 403].includes(Number(err?.statusCode ?? err?.status ?? err?.response?.status))
const errorText = (err: any): string => String(err?.data?.detail || err?.data?.title || err?.data?.message || err?.message || err).slice(0, 300)

export interface DayResult {
  date: string
  status: 'created' | 'resumed' | 'skipped' | 'failed'
  verdict: string
  statementId: number | null
  documentNo: string
  linesCreated: number
  linesSkipped: number
  errors: string[]
}

/**
 * Write ONE planned day. A failing line never rolls the day back — the
 * statement stays Drafted and a re-upload resumes it. Auth errors are re-thrown
 * so the route's refresh-retry can re-plan (idempotent thanks to `resume`).
 */
export const writeDay = async (event: any, token: any, plan: AccountPlan, day: PlannedDay, sourceLabel: string): Promise<DayResult> => {
  const result: DayResult = {
    date: day.date, status: 'skipped', verdict: day.verdict, statementId: null, documentNo: '',
    linesCreated: 0, linesSkipped: day.counts.known + day.counts.nonEur, errors: []
  }
  const bankAccount = plan.bankAccount
  if (!bankAccount || (day.verdict !== 'would_create' && day.verdict !== 'resume')) return result

  const organizationId = bankAccount.orgId || Number(getCookie(event, 'logship_organization_id') || 0)
  let statementId: number
  let lineNo: number

  if (day.verdict === 'resume') {
    statementId = day.existing[0].id
    result.documentNo = day.existing[0].documentNo
    lineNo = Math.floor(day.existing[0].maxLine / 10) * 10 + 10
    result.status = 'resumed'
  } else {
    try {
      const header: any = await event.context.fetch('models/c_bankstatement', 'POST', token, {
        AD_Org_ID: { id: organizationId, tableName: 'AD_Org' },
        C_BankAccount_ID: { id: bankAccount.id, tableName: 'C_BankAccount' },
        name: cut(`${bankAccount.name} ${day.date}`, 60),
        statementDate: day.date,
        // dateacct is NOT NULL and its AD default is not applied on REST POSTs.
        dateAcct: day.date,
        beginningBalance: centsToAmount(day.openingCents) ?? 0,
        endingBalance: centsToAmount(day.closingCents) ?? 0,
        description: cut(`CAMT.052 Datei-Import (${sourceLabel})`, 255),
        eftStatementReference: importRef(plan.iban, day.date),
        isManual: false
      })
      if (!header?.id) throw new Error('iDempiere lieferte keine Auszugs-ID')
      statementId = Number(header.id)
      result.documentNo = header.DocumentNo || ''
      lineNo = 10
      result.status = 'created'
    } catch (err: any) {
      if (isAuthError(err)) throw err
      result.status = 'failed'
      result.errors.push('Auszug: ' + errorText(err))
      return result
    }
  }
  result.statementId = statementId

  for (const line of day.lines) {
    if (line.verdict !== 'would_create') continue
    try {
      await event.context.fetch('models/c_bankstatementline', 'POST', token, buildLinePayload(line.entry, statementId, organizationId, lineNo))
      result.linesCreated++
      lineNo += 10
    } catch (err: any) {
      if (isAuthError(err)) throw err
      result.errors.push(`${line.entry.amount} ${line.entry.counterpartName || ''}: ${errorText(err)}`.trim())
    }
  }
  if (result.errors.length) result.status = 'failed'
  return result
}