import { useState, useEffect, useCallback } from 'react'
import { getLocale } from '@/lib/i18n'

export type DocSection = 'user-guide' | 'faq' | 'publishing' | 'payment' | 'fees-and-contributions'

export interface DocLink {
  id: DocSection
  title: string
  file: string
}

export function useDocs(docs: DocLink[]): {
  selectedDoc: DocSection
  docContent: string
  loading: boolean
  loadDoc: (docId: DocSection) => Promise<void>
} {
  const [selectedDoc, setSelectedDoc] = useState<DocSection>('user-guide')
  const [docContent, setDocContent] = useState<string>('')
  const [loading, setLoading] = useState(false)

  const loadDoc = useCallback(
    createLoadDoc({
      docs,
      setLoading,
      setSelectedDoc,
      setDocContent,
    }),
    [docs]
  )

  useEffect(() => {
    void loadDoc('user-guide')
  }, [loadDoc])

  return {
    selectedDoc,
    docContent,
    loading,
    loadDoc,
  }
}

function createLoadDoc(params: {
  docs: DocLink[]
  setSelectedDoc: (doc: DocSection) => void
  setDocContent: (value: string) => void
  setLoading: (value: boolean) => void
}): (docId: DocSection) => Promise<void> {
  return async (docId: DocSection): Promise<void> => {
    const doc = params.docs.find((d) => d.id === docId)
    if (!doc) {
      return
    }

    params.setLoading(true)
    params.setSelectedDoc(docId)

    try {
      const text = await fetchDocContent(doc.file)
      params.setDocContent(text)
    } catch (error) {
      console.error('[useDocs] Error loading doc:', error)
      params.setDocContent(await buildDocLoadErrorMarkdown())
    } finally {
      params.setLoading(false)
    }
  }
}

async function fetchDocContent(docFile: string): Promise<string> {
  const locale = getLocale()
  const response = await globalThis.fetch(`/api/docs/${docFile}?locale=${locale}`)
  if (!response.ok) {
    throw new Error('DOC_FETCH_FAILED')
  }
  return response.text()
}

async function buildDocLoadErrorMarkdown(): Promise<string> {
  // Import t dynamically to avoid circular dependency
  const { t } = await import('@/lib/i18n')
  return `# ${t('docs.error')}\n\n${t('docs.error.loadFailed')}`
}