import { useEffect, useState } from 'react'
import { Link } from 'react-router-dom'
import { Helmet } from 'react-helmet-async'
import type { TemplateEntity } from '../../../services/api/contracts'
import {
  deleteTemplate,
  deleteTemplates,
  getTemplateDashboardSummary,
  listTemplates,
  type TemplateDashboardSummary,
} from '../../../services/api/templates'
import { usePageContext } from '../../../shared/pageContext'
import { DashboardLayout } from '../../../layouts/DashboardLayout'

const initialSummary: TemplateDashboardSummary = {
  total: 0,
  published: 0,
  weeklyUsed: 0,
  draft: 0,
}

const FALLBACK_TEMPLATE_IMAGE = '/images/aitori-simulation-result.png'
const PAGE_SIZE = 8

export function TemplateListPage() {
  const { locale, path, copy } = usePageContext()
  const [items, setItems] = useState<TemplateEntity[]>([])
  const [summary, setSummary] = useState<TemplateDashboardSummary>(initialSummary)
  const [selectedIds, setSelectedIds] = useState<string[]>([])
  const [query, setQuery] = useState('')
  const [category, setCategory] = useState('')
  const [status, setStatus] = useState('')
  const [page, setPage] = useState(1)
  const [pageSize] = useState(PAGE_SIZE)
  const [total, setTotal] = useState(0)
  const [loading, setLoading] = useState(false)
  const pageCopy = copy.templateListPage

  useEffect(() => {
    getTemplateDashboardSummary().then(setSummary).catch(() => setSummary(initialSummary))
  }, [])

  useEffect(() => {
    let cancelled = false

    const load = async () => {
      setLoading(true)
      try {
        const result = await listTemplates({
          q: query.trim(),
          category,
          status,
          page,
          pageSize,
        })

        if (cancelled) return
        setItems(result.items)
        setTotal(result.total)
        setSelectedIds((current) => current.filter((id) => result.items.some((item) => item.id === id)))
      } catch {
        if (cancelled) return
        setItems([])
        setTotal(0)
        setSelectedIds([])
      } finally {
        if (!cancelled) {
          setLoading(false)
        }
      }
    }

    void load()

    return () => {
      cancelled = true
    }
  }, [category, page, pageSize, query, status])

  const toggleSelect = (templateId: string) => {
    setSelectedIds((current) =>
      current.includes(templateId)
        ? current.filter((id) => id !== templateId)
        : [...current, templateId],
    )
  }

  const allCurrentPageSelected =
    items.length > 0 && items.every((item) => selectedIds.includes(item.id))

  const handleToggleSelectAllCurrentPage = () => {
    const currentPageIds = items.map((item) => item.id)

    setSelectedIds((current) => {
      if (allCurrentPageSelected) {
        return current.filter((id) => !currentPageIds.includes(id))
      }

      return Array.from(new Set([...current, ...currentPageIds]))
    })
  }

  const handleDelete = async (templateId: string) => {
    const template = items.find((item) => item.id === templateId)
    if (!window.confirm(`确认删除模板「${template?.name || ''}」吗？`)) return

    await deleteTemplate(templateId)
    setItems((current) => current.filter((item) => item.id !== templateId))
    setSelectedIds((current) => current.filter((id) => id !== templateId))
    setTotal((current) => Math.max(0, current - 1))
  }

  const handleBulkDelete = async () => {
    if (selectedIds.length === 0) return
    if (!window.confirm(`确认删除已选中的 ${selectedIds.length} 个模板吗？`)) return

    const deletingIds = [...selectedIds]
    await deleteTemplates(deletingIds)
    setItems((current) => current.filter((item) => !deletingIds.includes(item.id)))
    setSelectedIds([])
    setTotal((current) => Math.max(0, current - deletingIds.length))
  }

  const getGenerationBadge = (template: TemplateEntity) => {
    if (template.makeTaskStatus === 'WAIT' || template.generationStatus === 'pending') {
      return pageCopy.statusBadgeMap?.pending || '排队中'
    }
    if (
      template.makeTaskStatus === 'PROCESSING' ||
      template.makeTaskStatus === 'STEP1_SUCCESS' ||
      template.generationStatus === 'processing'
    ) {
      return pageCopy.statusBadgeMap?.processing || '生成中'
    }
    if (template.makeTaskStatus === 'FAILED' || template.generationStatus === 'failed') {
      return pageCopy.statusBadgeMap?.failed || '生成失败'
    }
    return null
  }

  const getTemplateTarget = (template: TemplateEntity) => {
    if (template.makeTaskId) {
      return path(`/templates/tasks/${template.makeTaskId}`)
    }

    return null
  }

  const getCardImage = (template: TemplateEntity) => {
    const isProcessing =
      template.makeTaskStatus === 'WAIT'
      || template.makeTaskStatus === 'PROCESSING'
      || template.makeTaskStatus === 'STEP1_SUCCESS'
      || template.generationStatus === 'pending'
      || template.generationStatus === 'processing'

    if (isProcessing) {
      return template.referenceImage || template.image || FALLBACK_TEMPLATE_IMAGE
    }

    return template.image || FALLBACK_TEMPLATE_IMAGE
  }

  const totalPages = Math.max(1, Math.ceil(total / pageSize))
  const pages = Array.from({ length: totalPages }, (_, index) => index + 1)

  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">
        <div className="container">
          <div className="row align-items-end justify-content-between mb-4">
            <div className="col-lg-7">
              <span className="bg-base-color d-inline-block mb-15px fw-600 text-white text-uppercase 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 className="col-lg-4 text-lg-end mt-3 mt-lg-0">
              <Link to={path('/templates/new')} className="btn btn-extra-large btn-rounded btn-base-color btn-box-shadow fw-700">
                <i className="feather icon-feather-plus-circle me-8px"></i>{pageCopy.newTemplate}
              </Link>
            </div>
          </div>

          <div className="workbench-panel bg-white border-radius-8px box-shadow-extra-large p-25px mb-4 template-list-filter-panel">
            <div className="row g-3 align-items-end template-list-filter-grid">
              <div className="col-lg-5">
                <label htmlFor="template-search" className="fw-700 text-dark-gray mb-10px">{pageCopy.filters.searchLabel}</label>
                <div className="customer-search-field">
                  <i className="feather icon-feather-search"></i>
                  <input
                    id="template-search"
                    type="search"
                    className="form-control"
                    placeholder={pageCopy.filters.searchPlaceholder}
                    value={query}
                    onChange={(event) => {
                      setQuery(event.target.value)
                      setPage(1)
                    }}
                  />
                </div>
              </div>
              <div className="col-lg-3 col-md-6">
                <label htmlFor="category-filter" className="fw-700 text-dark-gray mb-10px">{pageCopy.filters.categoryLabel}</label>
                <select
                  id="category-filter"
                  className="form-select customer-filter-control"
                  value={category}
                  onChange={(event) => {
                    setCategory(event.target.value)
                    setPage(1)
                  }}
                >
                  {pageCopy.filters.categoryOptions.map((option: { value: string; label: string }) => (
                    <option key={option.value} value={option.value}>{option.label}</option>
                  ))}
                </select>
              </div>
              <div className="col-lg-3 col-md-6">
                <label htmlFor="status-filter" className="fw-700 text-dark-gray mb-10px">{pageCopy.filters.statusLabel}</label>
                <select
                  id="status-filter"
                  className="form-select customer-filter-control"
                  value={status}
                  onChange={(event) => {
                    setStatus(event.target.value)
                    setPage(1)
                  }}
                >
                  {pageCopy.filters.statusOptions.map((option: { value: string; label: string }) => (
                    <option key={option.value} value={option.value}>{option.label}</option>
                  ))}
                </select>
              </div>
            </div>
          </div>

          <div className="row row-cols-2 row-cols-lg-4 row-cols-md-4 g-3 mb-4">
            <div className="col"><div className="workbench-stat bg-white border-radius-8px p-20px"><span className="d-block fs-26 fw-800 text-dark-gray">{summary.total}</span><span className="fs-14">{pageCopy.stats.total}</span></div></div>
            <div className="col"><div className="workbench-stat bg-white border-radius-8px p-20px"><span className="d-block fs-26 fw-800 text-dark-gray">{summary.published}</span><span className="fs-14">{pageCopy.stats.published}</span></div></div>
            <div className="col"><div className="workbench-stat bg-white border-radius-8px p-20px"><span className="d-block fs-26 fw-800 text-dark-gray">{summary.weeklyUsed}</span><span className="fs-14">{pageCopy.stats.weeklyUsed}</span></div></div>
            <div className="col"><div className="workbench-stat bg-white border-radius-8px p-20px"><span className="d-block fs-26 fw-800 text-dark-gray">{summary.draft}</span><span className="fs-14">{pageCopy.stats.draft}</span></div></div>
          </div>
        </div>
      </section>

      <section className="pt-0">
        <div className="container">
          <div className="workbench-panel bg-white border-radius-8px box-shadow-extra-large p-30px template-list-results-panel">
            <div className="d-flex align-items-center justify-content-between flex-wrap gap-2 mb-25px template-list-results-header">
              <div>
                <span className="fs-14 fw-700 text-base-color text-uppercase">{pageCopy.resultBadge}</span>
                <h2 className="fw-700 text-medium-gray fs-26 mb-0">{pageCopy.resultTitle.replace('{{count}}', String(total))}</h2>
              </div>
              <div className="d-flex align-items-center gap-2 template-list-results-actions">
                <button
                  type="button"
                  onClick={handleToggleSelectAllCurrentPage}
                  disabled={items.length === 0}
                  className="btn btn-small btn-rounded btn-transparent-light-gray border border-1 border-color-dark-gray fw-700"
                >
                  {allCurrentPageSelected
                    ? pageCopy.deselectAll || '取消全选'
                    : pageCopy.selectAll || '全选'}
                </button>
                <button
                  type="button"
                  onClick={handleBulkDelete}
                  disabled={selectedIds.length === 0}
                  className="btn btn-small btn-rounded btn-base-color fw-700"
                >
                  {pageCopy.bulkDelete || '批量删除'}
                </button>
                <a href="#" className="btn btn-small btn-rounded btn-transparent-light-gray border border-1 border-color-dark-gray fw-700">{pageCopy.sortRecent}</a>
              </div>
            </div>

            <div className="template-grid">
              {items.map((template) => {
                const target = getTemplateTarget(template)
                const generationBadge = getGenerationBadge(template)
                const cardContent = (
                  <>
                    <div className="template-card-image">
                      {target ? (
                        <Link to={target} className="template-card-image-link" aria-label="查看模板封面">
                          <img src={getCardImage(template)} alt={template.name} />
                        </Link>
                      ) : (
                        <div className="template-card-image-link" aria-disabled="true">
                          <img src={getCardImage(template)} alt={template.name} />
                        </div>
                      )}
                      <div className="template-card-image-selection">
                        <input
                          type="checkbox"
                          checked={selectedIds.includes(template.id)}
                          aria-label={`${pageCopy.select || '选择'}${template.name}`}
                          onChange={() => toggleSelect(template.id)}
                          className="template-card-checkbox"
                        />
                      </div>
                      {generationBadge ? (
                        <div className="template-card-image-overlay">
                          <span className="template-status-badge">{generationBadge}</span>
                        </div>
                      ) : null}
                    </div>
                    <div className="template-card-content">
                      <div className="template-card-main">
                        <div className="template-card-meta">
                          <span>{pageCopy.categoryMap[template.category as keyof typeof pageCopy.categoryMap] || template.category}</span>
                          <span>{pageCopy.statusMap[template.status as keyof typeof pageCopy.statusMap] || template.status}</span>
                        </div>
                        {target ? (
                          <Link to={target} className="template-card-title-link" aria-label={template.name}>
                            <h3>{template.name}</h3>
                          </Link>
                        ) : (
                          <h3>{template.name}</h3>
                        )}
                        <p>{template.description}</p>
                      </div>
                      <div className="template-card-footer">
                        <span>{pageCopy.usedCount.replace('{{count}}', String(template.usedCount))}</span>
                        <div className="template-card-footer-actions">
                          <button
                            type="button"
                            className="template-card-delete-action"
                            aria-label={`${pageCopy.delete || '删除'}${template.name}`}
                            onClick={() => void handleDelete(template.id)}
                          >
                            {pageCopy.delete || '删除'}
                          </button>
                        </div>
                      </div>
                    </div>
                  </>
                )

                return (
                  <article
                    key={template.id}
                    className={`template-card${target ? '' : ' is-static'}${template.status === 'DRAFT' || generationBadge ? ' is-muted' : ''}`}
                  >
                    <div className="template-card-shell">{cardContent}</div>
                  </article>
                )
              })}
            </div>

            {!loading && items.length === 0 ? <p className="fs-15 text-medium-gray mb-0">{copy.common.empty}</p> : null}

            <div className="customer-pager">
              <button
                type="button"
                className={`customer-pager-link${page === 1 ? ' is-disabled' : ''}`}
                aria-label={pageCopy.pagination.prev}
                disabled={page === 1}
                onClick={() => setPage((current) => Math.max(1, current - 1))}
              >
                {pageCopy.pagination.prev}
              </button>
              {pages.map((pageNumber) => (
                <button
                  key={pageNumber}
                  type="button"
                  className={`customer-pager-link${page === pageNumber ? ' is-active' : ''}`}
                  aria-current={page === pageNumber ? 'page' : undefined}
                  onClick={() => setPage(pageNumber)}
                >
                  {pageNumber}
                </button>
              ))}
              <button
                type="button"
                className={`customer-pager-link${page === totalPages ? ' is-disabled' : ''}`}
                aria-label={pageCopy.pagination.next}
                disabled={page === totalPages}
                onClick={() => setPage((current) => Math.min(totalPages, current + 1))}
              >
                {pageCopy.pagination.next}
              </button>
            </div>
          </div>
        </div>
      </section>
    </DashboardLayout>
  )
}