import { Pencil, Plus, X } from 'lucide-react'
import type { ReactNode } from 'react'
import { useT } from '../i18n/useT'
import type { InvoiceItemTemplate } from '../types/invoice'
import { formatIrtInput } from '../utils/irtPrice'
import type { DraftAccount, DraftKeyPoint, DraftLineItem } from '../utils/invoiceDraft'
import {
  draftItemFromItemTemplate,
  emptyDraftAccount,
  emptyDraftItem,
  emptyDraftKeyPoint,
} from '../utils/invoiceDraft'
import formStyles from './InvoiceForm.module.css'
import styles from './InvoiceDraftFields.module.css'

function focusKeyPointInput(index: number) {
  const el = document.querySelector<HTMLInputElement>(`input[data-keypoint-index="${index}"]`)
  el?.focus()
  el?.select()
}

type Props = {
  itemTemplates: InvoiceItemTemplate[]
  items: DraftLineItem[]
  keyPoints: DraftKeyPoint[]
  accounts: DraftAccount[]
  selectedItemTemplateId: string
  onSelectedItemTemplateId: (id: string) => void
  onItemsChange: (items: DraftLineItem[]) => void
  onKeyPointsChange: (points: DraftKeyPoint[]) => void
  onAccountsChange: (accounts: DraftAccount[]) => void
  showItemTemplatePicker?: boolean
  /** Rendered after line items (before key points / accounts), e.g. totals row. */
  afterItems?: ReactNode
}

export function InvoiceDraftFields({
  itemTemplates,
  items,
  keyPoints,
  accounts,
  selectedItemTemplateId,
  onSelectedItemTemplateId,
  onItemsChange,
  onKeyPointsChange,
  onAccountsChange,
  showItemTemplatePicker = true,
  afterItems,
}: Props) {
  const t = useT()

  function updateItem(key: string, patch: Partial<DraftLineItem>) {
    onItemsChange(items.map((item) => (item.key === key ? { ...item, ...patch } : item)))
  }

  function removeItem(key: string) {
    if (items.length <= 1) return
    onItemsChange(items.filter((item) => item.key !== key))
  }

  function addFromItemTemplate() {
    const template = itemTemplates.find((entry) => entry.id === selectedItemTemplateId)
    if (!template) return
    const onlyEmpty =
      items.length === 1 &&
      !items[0].title.trim() &&
      !items[0].price.trim() &&
      !items[0].description.trim()
    onItemsChange(onlyEmpty ? [draftItemFromItemTemplate(template)] : [...items, draftItemFromItemTemplate(template)])
    onSelectedItemTemplateId('')
  }

  return (
    <>
      <div className={styles.itemsStack}>
        {items.map((item, index) => (
          <div key={item.key} className={styles.itemCard}>
            <div className={styles.itemCardHeader}>
              <span>{t('invoiceDraft.itemLabel', { index: index + 1 })}</span>
              <button
                type="button"
                className={styles.removeItemBtn}
                onClick={() => removeItem(item.key)}
                disabled={items.length <= 1}
                aria-label={t('invoiceDraft.removeItem')}
                title={t('invoiceDraft.removeItem')}
              >
                <X size={16} />
              </button>
            </div>
            <div className={styles.itemGrid}>
              <div className={formStyles.field}>
                <label>{t('invoiceDraft.fieldTitle')}</label>
                <input
                  value={item.title}
                  onChange={(e) => updateItem(item.key, { title: e.target.value })}
                  placeholder={t('invoiceDraft.fieldTitlePlaceholder')}
                />
              </div>
              <div className={formStyles.field}>
                <label>{t('invoiceDraft.fieldDuration')}</label>
                <input
                  value={item.duration}
                  onChange={(e) => updateItem(item.key, { duration: e.target.value })}
                  placeholder={t('invoiceDraft.fieldDurationPlaceholder')}
                />
              </div>
              <div className={formStyles.field}>
                <label>{t('invoiceDraft.fieldWorktime')}</label>
                <input
                  value={item.worktime}
                  onChange={(e) => updateItem(item.key, { worktime: e.target.value })}
                  placeholder={t('invoiceDraft.fieldWorktimePlaceholder')}
                />
              </div>
              <div className={formStyles.field}>
                <label>{t('invoiceDraft.fieldPrice')}</label>
                <input
                  inputMode="numeric"
                  value={item.price}
                  onChange={(e) => updateItem(item.key, { price: formatIrtInput(e.target.value) })}
                  placeholder="0"
                />
              </div>
              <div className={formStyles.field}>
                <label>{t('invoiceDraft.fieldDiscountedPrice')}</label>
                <input
                  inputMode="numeric"
                  value={item.discountedPrice}
                  onChange={(e) =>
                    updateItem(item.key, { discountedPrice: formatIrtInput(e.target.value) })
                  }
                  placeholder={t('invoiceDraft.fieldDiscountedPricePlaceholder')}
                />
              </div>
              <div className={`${formStyles.field} ${styles.descField}`}>
                <label>{t('invoiceDraft.fieldDescription')}</label>
                <textarea
                  rows={2}
                  value={item.description}
                  onChange={(e) => updateItem(item.key, { description: e.target.value })}
                  placeholder={t('invoiceDraft.fieldDescriptionPlaceholder')}
                />
              </div>
            </div>
          </div>
        ))}
      </div>

      <div className={styles.itemActions}>
        {showItemTemplatePicker ? (
          <div className={styles.itemActionsLeft}>
            <select
              id="item-template-pick"
              className={styles.compactSelect}
              value={selectedItemTemplateId}
              onChange={(e) => onSelectedItemTemplateId(e.target.value)}
              aria-label={t('invoiceDraft.addFromTemplateAria')}
            >
              <option value="">{t('invoiceDraft.addFromTemplate')}</option>
              {itemTemplates.map((template) => (
                <option key={template.id} value={template.id}>
                  {template.title}
                </option>
              ))}
            </select>
            <button
              type="button"
              className={`${formStyles.btn} ${formStyles.btnGhost} ${styles.compactBtn}`}
              onClick={addFromItemTemplate}
              disabled={!selectedItemTemplateId}
            >
              <Plus size={14} />
              {t('invoiceDraft.add')}
            </button>
          </div>
        ) : (
          <div />
        )}
        <button
          type="button"
          className={`${formStyles.btn} ${formStyles.btnGhost} ${styles.compactBtn}`}
          onClick={() => onItemsChange([...items, emptyDraftItem()])}
        >
          <Pencil size={14} />
          {t('invoiceDraft.addCustomItem')}
        </button>
      </div>

      {afterItems}

      <div className={styles.blockSection}>
        <div className={styles.blockHeader}>
          <h4 className={styles.blockTitle}>{t('invoiceDraft.keyPoints')}</h4>
          <button
            type="button"
            className={`${formStyles.btn} ${formStyles.btnGhost}`}
            onClick={() => onKeyPointsChange([...keyPoints, emptyDraftKeyPoint()])}
          >
            <Plus size={16} />
            {t('invoiceDraft.addPoint')}
          </button>
        </div>
        {keyPoints.length === 0 ? (
          <p className={styles.templateHint}>{t('invoiceDraft.noKeyPoints')}</p>
        ) : (
          <div className={styles.repeatStack}>
            {keyPoints.map((point, index) => (
              <div key={point.key} className={styles.repeatRow}>
                <div className={`${formStyles.field} ${styles.flexGrow} ${styles.fieldNoLabel}`}>
                  <input
                    data-keypoint-index={index}
                    value={point.text}
                    onChange={(e) =>
                      onKeyPointsChange(
                        keyPoints.map((p) =>
                          p.key === point.key ? { ...p, text: e.target.value } : p,
                        ),
                      )
                    }
                    onKeyDown={(e) => {
                      if (e.key !== 'Enter') return
                      e.preventDefault()
                      const next = index + 1
                      if (next < keyPoints.length) {
                        focusKeyPointInput(next)
                        return
                      }
                      onKeyPointsChange([...keyPoints, emptyDraftKeyPoint()])
                      window.setTimeout(() => focusKeyPointInput(next), 0)
                    }}
                    placeholder={t('invoiceDraft.keyPointPlaceholder')}
                    aria-label={t('invoiceDraft.keyPointAria', { index: index + 1 })}
                  />
                </div>
                <button
                  type="button"
                  className={styles.removeFieldBtn}
                  onClick={() => onKeyPointsChange(keyPoints.filter((p) => p.key !== point.key))}
                  aria-label={t('invoiceDraft.removeKeyPoint')}
                  title={t('invoiceDraft.removeKeyPoint')}
                >
                  <X size={16} />
                </button>
              </div>
            ))}
          </div>
        )}
      </div>

      <div className={styles.blockSection}>
        <div className={styles.blockHeader}>
          <h4 className={styles.blockTitle}>{t('invoiceDraft.accounts')}</h4>
          <button
            type="button"
            className={`${formStyles.btn} ${formStyles.btnGhost}`}
            onClick={() => onAccountsChange([...accounts, emptyDraftAccount()])}
          >
            <Plus size={16} />
            {t('invoiceDraft.addAccount')}
          </button>
        </div>
        {accounts.length === 0 ? (
          <p className={styles.templateHint}>{t('invoiceDraft.noAccounts')}</p>
        ) : (
          <div className={styles.repeatStack}>
            {accounts.map((acc, index) => {
              const showLabels = index === 0
              return (
                <div
                  key={acc.key}
                  className={`${styles.accountRow} ${showLabels ? '' : styles.accountRowPlain}`}
                >
                  <div className={`${formStyles.field} ${styles.accountCol2}`}>
                    {showLabels ? <label>{t('invoiceDraft.bankName')}</label> : null}
                    <input
                      value={acc.bankName}
                      onChange={(e) =>
                        onAccountsChange(
                          accounts.map((a) =>
                            a.key === acc.key ? { ...a, bankName: e.target.value } : a,
                          ),
                        )
                      }
                      placeholder={t('invoiceDraft.bankName')}
                      aria-label={t('invoiceDraft.bankName')}
                    />
                  </div>
                  <div className={`${formStyles.field} ${styles.accountCol2}`}>
                    {showLabels ? <label>{t('invoiceDraft.accountHolder')}</label> : null}
                    <input
                      value={acc.accountHolderName}
                      onChange={(e) =>
                        onAccountsChange(
                          accounts.map((a) =>
                            a.key === acc.key ? { ...a, accountHolderName: e.target.value } : a,
                          ),
                        )
                      }
                      placeholder={t('invoiceDraft.accountHolder')}
                      aria-label={t('invoiceDraft.accountHolder')}
                    />
                  </div>
                  <div className={`${formStyles.field} ${styles.accountCol3}`}>
                    {showLabels ? <label>{t('invoiceDraft.cardNumber')}</label> : null}
                    <input
                      value={acc.cardNumber}
                      onChange={(e) =>
                        onAccountsChange(
                          accounts.map((a) =>
                            a.key === acc.key ? { ...a, cardNumber: e.target.value } : a,
                          ),
                        )
                      }
                      placeholder={t('invoiceDraft.optional')}
                      aria-label={t('invoiceDraft.cardNumber')}
                    />
                  </div>
                  <div className={`${formStyles.field} ${styles.accountCol5}`}>
                    {showLabels ? <label>{t('invoiceDraft.iban')}</label> : null}
                    <input
                      value={acc.iban}
                      onChange={(e) =>
                        onAccountsChange(
                          accounts.map((a) =>
                            a.key === acc.key ? { ...a, iban: e.target.value } : a,
                          ),
                        )
                      }
                      placeholder={t('invoiceDraft.optional')}
                      aria-label={t('invoiceDraft.iban')}
                    />
                  </div>
                  <button
                    type="button"
                    className={styles.removeFieldBtn}
                    onClick={() => onAccountsChange(accounts.filter((a) => a.key !== acc.key))}
                    aria-label={t('invoiceDraft.removeAccount')}
                    title={t('invoiceDraft.removeAccount')}
                  >
                    <X size={16} />
                  </button>
                </div>
              )
            })}
          </div>
        )}
      </div>
    </>
  )
}