import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogHeader,
  DialogTitle
} from '@/components/ui/dialog'
import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs'
import {
  isRadixDialogOpen,
  OPEN_NEW_POST_SHORTCUT_KEY,
  shouldIgnoreKeyboardShortcutEvent
} from '@/lib/keyboard-shortcuts'
import { cn } from '@/lib/utils'
import postEditorService from '@/services/post-editor.service'
import { useCallback, useEffect, useMemo, useState, type ReactNode } from 'react'
import { marked } from 'marked'
import { KeyboardShortcutsHelpContext } from '@/contexts/keyboard-shortcuts-help-context'
import { useTranslation } from 'react-i18next'
import readmeMarkdown from '../../../README.md?raw'

function Kbd({ children }: { children: ReactNode }) {
  return (
    <kbd className="pointer-events-none inline-flex h-6 min-w-[1.25rem] shrink-0 items-center justify-center rounded border border-border bg-muted px-1.5 font-mono text-[11px] font-medium text-muted-foreground">
      {children}
    </kbd>
  )
}

function KbdRow({ keys, label }: { keys: ReactNode; label: string }) {
  return (
    <div className="flex flex-col gap-1.5 sm:flex-row sm:items-start sm:justify-between sm:gap-4">
      <span className="text-muted-foreground leading-snug">{label}</span>
      <div className="flex flex-wrap items-center gap-1 sm:justify-end">{keys}</div>
    </div>
  )
}

function ShortcutsPanel() {
  const { t } = useTranslation()
  return (
    <div className="space-y-4 pt-1 text-sm">
      <p className="text-sm text-muted-foreground">{t('shortcuts.intro')}</p>
      <section className="space-y-3">
        <h3 className="text-xs font-semibold uppercase tracking-wide text-muted-foreground">
          {t('shortcuts.sectionApp')}
        </h3>
        <div className="space-y-3">
          <KbdRow label={t('shortcuts.openHelp')} keys={<Kbd>F1</Kbd>} />
          <KbdRow
            label={t('shortcuts.focusPrimary')}
            keys={
              <>
                <Kbd>Shift</Kbd>
                <span className="text-muted-foreground">+</span>
                <Kbd>Alt</Kbd>
                <span className="text-muted-foreground">+</span>
                <Kbd>F</Kbd>
              </>
            }
          />
          <KbdRow
            label={t('shortcuts.focusSecondary')}
            keys={
              <>
                <Kbd>Shift</Kbd>
                <span className="text-muted-foreground">+</span>
                <Kbd>Alt</Kbd>
                <span className="text-muted-foreground">+</span>
                <Kbd>S</Kbd>
              </>
            }
          />
          <KbdRow
            label={t('shortcuts.newNote')}
            keys={
              <>
                <Kbd>Shift</Kbd>
                <span className="text-muted-foreground">+</span>
                <Kbd>Alt</Kbd>
                <span className="text-muted-foreground">+</span>
                <Kbd>N</Kbd>
              </>
            }
          />
        </div>
      </section>
      <section className="space-y-3">
        <h3 className="text-xs font-semibold uppercase tracking-wide text-muted-foreground">
          {t('shortcuts.sectionSearch')}
        </h3>
        <div className="space-y-3">
          <KbdRow
            label={t('shortcuts.searchSuggest')}
            keys={
              <>
                <Kbd>↑</Kbd>
                <Kbd>↓</Kbd>
                <span className="px-1 text-muted-foreground">{t('shortcuts.then')}</span>
                <Kbd>Enter</Kbd>
              </>
            }
          />
          <KbdRow label={t('shortcuts.searchDismiss')} keys={<Kbd>Esc</Kbd>} />
        </div>
      </section>
      <section className="space-y-3">
        <h3 className="text-xs font-semibold uppercase tracking-wide text-muted-foreground">
          {t('shortcuts.sectionStandard')}
        </h3>
        <div className="space-y-3">
          <KbdRow
            label={t('shortcuts.tabNavigate')}
            keys={
              <>
                <Kbd>Tab</Kbd>
                <span className="px-1 text-muted-foreground">{t('shortcuts.or')}</span>
                <Kbd>Shift</Kbd>
                <span className="text-muted-foreground">+</span>
                <Kbd>Tab</Kbd>
              </>
            }
          />
          <KbdRow
            label={t('shortcuts.activate')}
            keys={
              <>
                <Kbd>Enter</Kbd>
                <span className="px-1 text-muted-foreground">{t('shortcuts.or')}</span>
                <Kbd>Space</Kbd>
              </>
            }
          />
          <KbdRow label={t('shortcuts.closeOverlays')} keys={<Kbd>Esc</Kbd>} />
          <KbdRow
            label={t('shortcuts.scrollWhenFocused')}
            keys={
              <>
                <Kbd>↑</Kbd>
                <Kbd>↓</Kbd>
                <Kbd>PgUp</Kbd>
                <Kbd>PgDn</Kbd>
                <Kbd>Home</Kbd>
                <Kbd>End</Kbd>
              </>
            }
          />
          <KbdRow
            label={t('shortcuts.browserBack')}
            keys={
              <>
                <Kbd>Alt</Kbd>
                <span className="text-muted-foreground">+</span>
                <Kbd>←</Kbd>
              </>
            }
          />
        </div>
      </section>
    </div>
  )
}

function ReadmeOverviewPanel({ className }: { className?: string }) {
  const readmeHtml = useMemo(() => {
    // README is local project content; render it as regular markdown (not note-content parsing).
    const html = marked.parse(readmeMarkdown, {
      gfm: true,
      breaks: true
    })
    const resolved = typeof html === 'string' ? html : ''
    return resolved.replace(/<a\s+href=/g, '<a target="_blank" rel="noopener noreferrer" href=')
  }, [])

  return (
    <div
      className={cn(
        'min-w-0 pt-1 text-sm prose prose-sm dark:prose-invert max-w-none',
        '[&_a]:text-link-uri [&_a]:no-underline hover:[&_a]:text-primary hover:[&_a]:underline',
        '[&_code]:bg-muted [&_code]:px-1 [&_code]:py-0.5 [&_code]:rounded',
        '[&_pre]:bg-muted [&_pre]:p-3 [&_pre]:rounded-lg [&_pre]:overflow-x-auto',
        '[&_img]:max-w-full [&_img]:h-auto [&_img]:rounded-md',
        className
      )}
      dangerouslySetInnerHTML={{ __html: readmeHtml }}
    />
  )
}

export function KeyboardShortcutsHelpProvider({ children }: { children: ReactNode }) {
  const [open, setOpen] = useState(false)
  const openHelp = useCallback(() => setOpen(true), [])
  const { t } = useTranslation()

  useEffect(() => {
    const onKeyDown = (e: KeyboardEvent) => {
      if (open) return
      if (shouldIgnoreKeyboardShortcutEvent(e.target)) return
      if (isRadixDialogOpen()) return

      if (e.key === 'F1' && !e.ctrlKey && !e.metaKey && !e.altKey) {
        e.preventDefault()
        setOpen(true)
        return
      }

      if (
        e.altKey &&
        e.shiftKey &&
        e.key.toLowerCase() === OPEN_NEW_POST_SHORTCUT_KEY &&
        !e.ctrlKey &&
        !e.metaKey
      ) {
        e.preventDefault()
        postEditorService.requestOpenNewPost()
      }
    }

    document.addEventListener('keydown', onKeyDown, true)
    return () => document.removeEventListener('keydown', onKeyDown, true)
  }, [open])

  const value = useMemo(() => ({ openHelp }), [openHelp])

  return (
    <KeyboardShortcutsHelpContext.Provider value={value}>
      {children}
      <Dialog open={open} onOpenChange={setOpen}>
        <DialogContent className="flex max-h-[min(88vh,40rem)] max-w-2xl flex-col gap-0 overflow-hidden p-6 sm:max-w-2xl">
          <DialogHeader className="shrink-0 space-y-1 pb-2 pr-8 text-left">
            <DialogTitle>{t('help.title')}</DialogTitle>
            <DialogDescription className="sr-only">{t('shortcuts.intro')}</DialogDescription>
          </DialogHeader>
          <Tabs defaultValue="shortcuts" className="flex min-h-0 flex-1 flex-col gap-2">
            <TabsList className="grid w-full shrink-0 grid-cols-2">
              <TabsTrigger value="shortcuts">{t('help.tabShortcuts')}</TabsTrigger>
              <TabsTrigger value="overview">{t('help.tabOverview')}</TabsTrigger>
            </TabsList>
            <TabsContent
              value="shortcuts"
              className="mt-0 max-h-[min(62vh,32rem)] min-h-0 flex-1 overflow-y-auto overscroll-contain pr-4 [scrollbar-gutter:stable] data-[state=inactive]:hidden"
            >
              <ShortcutsPanel />
            </TabsContent>
            <TabsContent
              value="overview"
              className="mt-0 max-h-[min(62vh,32rem)] min-h-0 flex-1 overflow-y-auto overscroll-contain pr-4 [scrollbar-gutter:stable] data-[state=inactive]:hidden"
            >
              <ReadmeOverviewPanel />
            </TabsContent>
          </Tabs>
        </DialogContent>
      </Dialog>
    </KeyboardShortcutsHelpContext.Provider>
  )
}