export function isImageFileType(fileType) {
  return !!(fileType && String(fileType).startsWith('image/'))
}

export function fileExtLabel(name) {
  const ext = String(name || '').split('.').pop()
  return ext ? ext.toUpperCase() : 'FILE'
}

/** 展示用 YYYY-MM-DD；无有效日期返回 — */
export function formatInvoiceDateYmd(value) {
  if (value == null || value === '') return '—'
  const s = String(value).trim()
  const m = s.match(/^(\d{4}-\d{2}-\d{2})/)
  if (m) return m[1]
  const d = new Date(s)
  if (Number.isNaN(d.getTime())) return '—'
  const y = d.getFullYear()
  const mo = String(d.getMonth() + 1).padStart(2, '0')
  const day = String(d.getDate()).padStart(2, '0')
  return `${y}-${mo}-${day}`
}

function invoiceFileList(inv) {
  const raw = Array.isArray(inv?.attachments) ? inv.attachments : []
  if (raw.length) {
    return raw.map((a) => ({
      id: String(a.id || a.attachmentId || ''),
      fileName: a.fileName || a.file_name || '发票附件',
      fileType: a.fileType || a.file_type || ''
    }))
  }
  const aid = inv?.attachmentId || inv?.attachment_id
  if (aid) {
    return [
      {
        id: String(aid),
        fileName: inv.fileName || inv.file_name || '发票附件',
        fileType: inv.fileType || inv.file_type || ''
      }
    ]
  }
  return []
}

/**
 * 发票列表行 → 附件粒度选项
 * @returns {{ key, invoiceId, attachmentId, amount, createTime, fileName, fileType, previewUrl, previewLoading }[]}
 */
export function buildAttachItemsFromInvoiceRows(rows) {
  const items = []
  for (const row of rows || []) {
    const createTime = row.createTime || row.create_time || ''
    for (const file of invoiceFileList(row)) {
      if (!file.id) continue
      items.push({
        key: `${row.id}:${file.id}`,
        invoiceId: String(row.id),
        attachmentId: file.id,
        amount: row.amount,
        createTime,
        fileName: file.fileName,
        fileType: file.fileType,
        previewUrl: '',
        previewLoading: false
      })
    }
  }
  return items
}

/**
 * 确定勾选：已加载项优先；draft 中仍勾选但不在已加载列表的旧已选项保留（防分页冲掉）
 */
export function mergeInvoicePicksByDraftKeys(draftKeys, attachItems, previousPicks) {
  const set = new Set(draftKeys || [])
  const fromLoaded = (attachItems || []).filter((i) => set.has(i.key))
  const loadedKeys = new Set(fromLoaded.map((i) => i.key))
  const fromPrev = (previousPicks || []).filter(
    (p) => set.has(p.key) && !loadedKeys.has(p.key)
  )
  const byKey = new Map()
  for (const p of fromPrev) byKey.set(p.key, { ...p })
  for (const i of fromLoaded) {
    const prev = byKey.get(i.key)
    byKey.set(i.key, {
      ...i,
      previewUrl: i.previewUrl || prev?.previewUrl || ''
    })
  }
  return Array.from(set)
    .map((k) => byKey.get(k))
    .filter(Boolean)
}