import React, { useEffect, useState } from 'react'
import { Link, useSearchParams } from 'react-router-dom'
import { Helmet } from 'react-helmet-async'
import { DashboardLayout } from '../../../layouts/DashboardLayout'
import { listCustomers } from '../../../services/api/customers'
import type { CustomerEntity } from '../../../services/api/customers'
import type { SimulationTemplateOption } from '../../../services/api/contracts'
import {
  createSimulation,
  listSimulationTemplates,
  uploadMedia,
} from '../../../services/api/simulations'
import {
  TEMPLATE_LIMIT,
  usePageContext,
  usePreviewUrl,
} from '../../../shared/pageContext'

export function StylistSimulationPage() {
  const [searchParams] = useSearchParams()
  const { locale, navigate, path, copy } = usePageContext()
  const presetCustomerId = searchParams.get('customerId') ?? ''
  const pageCopy = copy.simulationCreatePage

  const [bindCustomer, setBindCustomer] = useState(Boolean(presetCustomerId))
  const [selectedCustomerId, setSelectedCustomerId] = useState(presetCustomerId)
  const [templateSource, setTemplateSource] = useState<'STYLIST' | 'SYSTEM'>('STYLIST')
  const [selectedTemplates, setSelectedTemplates] = useState<string[]>([])
  const [customers, setCustomers] = useState<CustomerEntity[]>([])
  const [templates, setTemplates] = useState<SimulationTemplateOption[]>([])
  const [file, setFile] = useState<File | null>(null)
  const [originImageUrl, setOriginImageUrl] = useState('')
  const [remark, setRemark] = useState('')
  const [uploading, setUploading] = useState(false)
  const [submitting, setSubmitting] = useState(false)
  const [error, setError] = useState('')

  const previewUrl = usePreviewUrl(file, originImageUrl || '/images/aitori-before-photo.png')
  const selectedCustomer = customers.find((item) => item.id === selectedCustomerId) || null

  useEffect(() => {
    void listCustomers().then((result) => {
      setCustomers(result.items)
      if (presetCustomerId && result.items.some((item) => item.id === presetCustomerId)) {
        setBindCustomer(true)
        setSelectedCustomerId(presetCustomerId)
      }
    })
  }, [presetCustomerId])

  useEffect(() => {
    void listSimulationTemplates({
      source: templateSource,
      page: 1,
      pageSize: 12,
    })
      .then((result) => {
        setTemplates(result.items)
      })
      .catch(() => {
        setTemplates([])
      })
  }, [templateSource])

  const toggleTemplate = (templateId: string) => {
    setSelectedTemplates((current) => {
      if (current.includes(templateId)) {
        return current.filter((item) => item !== templateId)
      }
      if (current.length >= TEMPLATE_LIMIT) {
        return current
      }
      return [...current, templateId]
    })
  }

  const handleUpload = async (event: React.ChangeEvent<HTMLInputElement>) => {
    const nextFile = event.target.files?.[0] || null
    setFile(nextFile)
    setError('')

    if (!nextFile) {
      setOriginImageUrl('')
      return
    }

    setUploading(true)
    try {
      const uploaded = await uploadMedia(nextFile, 'ai-user-origin-image')
      setOriginImageUrl(uploaded.url)
    } catch (uploadError) {
      setOriginImageUrl('')
      setError(
        uploadError instanceof Error
          ? uploadError.message
          : pageCopy.errors.submitFailed,
      )
    } finally {
      setUploading(false)
    }
  }

  const handleSubmit = async (event: React.FormEvent<HTMLFormElement>) => {
    event.preventDefault()
    if (submitting) return

    if (bindCustomer && !selectedCustomerId) {
      setError(pageCopy.errors.customerRequired)
      return
    }

    if (!originImageUrl) {
      setError(pageCopy.errors.originRequired)
      return
    }

    if (selectedTemplates.length === 0) {
      setError(pageCopy.errors.templateRequired)
      return
    }

    setError('')
    setSubmitting(true)
    try {
      const response = await createSimulation({
        customerId: bindCustomer && selectedCustomerId ? selectedCustomerId : undefined,
        originImage: originImageUrl,
        templateIds: selectedTemplates,
        simulateRemark: remark,
      })
      navigate(path(`/simulation/result/${response.simulationId}`))
    } catch (submitError) {
      setError(
        submitError instanceof Error
          ? submitError.message
          : pageCopy.errors.submitFailed,
      )
    } finally {
      setSubmitting(false)
    }
  }

  return (
    <DashboardLayout>
      <Helmet>
        <html lang={locale === 'ja' ? 'ja' : 'zh-CN'} />
        <title>{`Aitori Stylist | ${pageCopy.title}`}</title>
        <meta name="description" content={pageCopy.description} />
      </Helmet>
      <section className="stylist-workbench-top ipad-top-space-margin mb-2">
        <div className="container">
          <div className="d-flex align-items-center justify-content-between flex-wrap gap-3 mb-4">
            <Link
              to={path('/dashboard')}
              className="btn btn-small btn-rounded btn-transparent-light-gray border border-1 border-color-dark-gray fw-700"
            >
              <i className="feather icon-feather-arrow-left me-6px"></i>
              {pageCopy.back}
            </Link>
            <button
              type="submit"
              form="simulation-form"
              disabled={submitting || uploading}
              className="btn btn-large btn-rounded btn-base-color btn-box-shadow fw-700"
            >
              <i className="feather icon-feather-cpu me-10px"></i>
              {submitting ? '...' : pageCopy.submit}
            </button>
          </div>
          <div className="workbench-panel bg-white border-radius-8px box-shadow-extra-large p-30px">
            <span className="bg-base-color d-inline-block mb-15px fw-600 text-white border-radius-30px ps-20px pe-20px fs-12">
              {pageCopy.badge}
            </span>
            <h1 className="fw-700 text-dark-gray ls-minus-1px mb-10px">{pageCopy.title}</h1>
            <p className="fs-18 lh-30 mb-0">{pageCopy.lead}</p>
          </div>
        </div>
      </section>
      <section className="pt-0">
        <div className="container">
          <form id="simulation-form" onSubmit={handleSubmit}>
            <div className="simulation-step workbench-panel bg-white border-radius-8px box-shadow-extra-large p-30px mb-4">
              <div className="simulation-step-heading">
                <span>1</span>
                <div>
                  <span className="fs-14 fw-700 text-base-color">{pageCopy.bindCustomer}</span>
                  <h2 className="fw-700 text-dark-gray fs-26 mb-0">{pageCopy.bindCustomer}</h2>
                </div>
              </div>
              <div className="simulation-choice-grid mt-25px">
                <label className="simulation-choice-card">
                  <input
                    type="radio"
                    name="customer-mode"
                    aria-label={pageCopy.bindCustomer}
                    checked={bindCustomer}
                    onChange={() => setBindCustomer(true)}
                  />
                  <span className="simulation-choice-icon">
                    <i className="feather icon-feather-user-check"></i>
                  </span>
                  <strong>{pageCopy.bindCustomer}</strong>
                  <small>{pageCopy.customerPlaceholder}</small>
                </label>
                <label className="simulation-choice-card">
                  <input
                    type="radio"
                    name="customer-mode"
                    aria-label={pageCopy.noCustomer}
                    checked={!bindCustomer}
                    onChange={() => setBindCustomer(false)}
                  />
                  <span className="simulation-choice-icon">
                    <i className="feather icon-feather-user-x"></i>
                  </span>
                  <strong>{pageCopy.noCustomer}</strong>
                  <small>{pageCopy.noCustomer}</small>
                </label>
              </div>
              <div className="simulation-selected-customer mt-25px">
                <img
                  src={selectedCustomer?.avatar || '/images/aitori-before-photo.png'}
                  alt={selectedCustomer?.name || pageCopy.customerLabel}
                />
                <div className="w-100">
                  <label
                    htmlFor="simulation-customer-select"
                    className="fs-14 text-medium-gray d-block"
                  >
                    {pageCopy.customerLabel}
                  </label>
                  <select
                    id="simulation-customer-select"
                    aria-label={pageCopy.customerLabel}
                    className="form-select customer-edit-control mt-10px"
                    value={selectedCustomerId}
                    disabled={!bindCustomer}
                    onChange={(event) => setSelectedCustomerId(event.target.value)}
                  >
                    <option value="">{pageCopy.customerPlaceholder}</option>
                    {customers.map((item) => (
                      <option key={item.id} value={item.id}>
                        {item.name}
                      </option>
                    ))}
                  </select>
                </div>
              </div>
            </div>

            <div className="simulation-step workbench-panel bg-white border-radius-8px box-shadow-extra-large p-30px mb-4">
              <div className="simulation-step-heading">
                <span>2</span>
                <div>
                  <span className="fs-14 fw-700 text-base-color">{pageCopy.upload}</span>
                  <h2 className="fw-700 text-dark-gray fs-26 mb-0">{pageCopy.upload}</h2>
                </div>
              </div>
              <label htmlFor="simulation-photo-upload" className="simulation-photo-upload mt-25px">
                <input
                  id="simulation-photo-upload"
                  aria-label={pageCopy.upload}
                  type="file"
                  accept="image/*"
                  onChange={handleUpload}
                />
                <img id="simulation-photo-preview" src={previewUrl} alt={pageCopy.upload} />
                <span>
                  <i className="feather icon-feather-upload me-8px"></i>
                  {uploading ? '...' : pageCopy.upload}
                </span>
                <small className="d-block mt-10px text-medium-gray">{pageCopy.uploadHint}</small>
              </label>
            </div>

            <div className="simulation-step workbench-panel bg-white border-radius-8px box-shadow-extra-large p-30px">
              <div className="simulation-step-heading">
                <span>3</span>
                <div>
                  <span className="fs-14 fw-700 text-base-color">{pageCopy.myTemplates}</span>
                  <h2 className="fw-700 text-dark-gray fs-26 mb-0">{pageCopy.myTemplates}</h2>
                </div>
              </div>
              <div className="simulation-choice-grid mt-25px mb-30px">
                <label className="simulation-choice-card">
                  <input
                    type="radio"
                    name="template-source"
                    aria-label={pageCopy.myTemplates}
                    checked={templateSource === 'STYLIST'}
                    onChange={() => setTemplateSource('STYLIST')}
                  />
                  <span className="simulation-choice-icon">
                    <i className="feather icon-feather-scissors"></i>
                  </span>
                  <strong>{pageCopy.myTemplates}</strong>
                  <small>{pageCopy.myTemplates}</small>
                </label>
                <label className="simulation-choice-card">
                  <input
                    type="radio"
                    name="template-source"
                    aria-label={pageCopy.systemTemplates}
                    checked={templateSource === 'SYSTEM'}
                    onChange={() => setTemplateSource('SYSTEM')}
                  />
                  <span className="simulation-choice-icon">
                    <i className="feather icon-feather-layers"></i>
                  </span>
                  <strong>{pageCopy.systemTemplates}</strong>
                  <small>{pageCopy.systemTemplates}</small>
                </label>
              </div>
              <div className="d-flex align-items-center justify-content-between flex-wrap gap-2 mb-25px">
                <p className="mb-0 fs-15 text-medium-gray">
                  {pageCopy.selectedCount.replace('{{count}}', String(selectedTemplates.length))}
                </p>
              </div>
              <div className="simulation-template-grid">
                {templates.length === 0 ? (
                  <p className="text-medium-gray mb-0">{pageCopy.emptyTemplates}</p>
                ) : (
                  templates.map((template) => {
                    const active = selectedTemplates.includes(template.id)

                    return (
                      <label key={template.id} className="simulation-template-card">
                        <input
                          type="checkbox"
                          aria-label={template.templateName}
                          checked={active}
                          disabled={!active && selectedTemplates.length >= TEMPLATE_LIMIT}
                          onChange={() => toggleTemplate(template.id)}
                        />
                        <img
                          src={template.coverUrl || '/images/aitori-simulation-result.png'}
                          alt={template.templateName}
                        />
                        <span>{template.templateName}</span>
                      </label>
                    )
                  })
                )}
              </div>
              <div className="mt-25px">
                <label
                  htmlFor="simulation-remark"
                  className="fs-14 fw-700 text-dark-gray d-block mb-10px"
                >
                  {pageCopy.remark}
                </label>
                <textarea
                  id="simulation-remark"
                  className="form-control"
                  value={remark}
                  placeholder={pageCopy.remarkPlaceholder}
                  onChange={(event) => setRemark(event.target.value)}
                />
              </div>
            </div>

            <div className="customer-edit-actions workbench-panel border-radius-8px p-25px mt-4">
              <div>
                <strong>{pageCopy.submit}</strong>
                <span>{pageCopy.lead}</span>
              </div>
              <div className="d-flex flex-wrap gap-2 align-items-center">
                {error ? (
                  <span className="fs-14 text-red me-2" role="alert">
                    {error}
                  </span>
                ) : null}
                <Link
                  to={path('/dashboard')}
                  className="btn btn-large btn-rounded btn-transparent-light-gray border border-1 border-color-dark-gray fw-700"
                >
                  {copy.common.cancel}
                </Link>
                <button
                  type="submit"
                  disabled={submitting || uploading}
                  className="btn btn-large btn-rounded btn-base-color btn-box-shadow fw-700"
                >
                  <i className="feather icon-feather-cpu me-10px"></i>
                  {submitting ? '...' : pageCopy.submit}
                </button>
              </div>
            </div>
          </form>
        </div>
      </section>
    </DashboardLayout>
  )
}