// src/renderer/pages/KnowledgeBasePage.tsx
// Phase 13.2: 로컬 RAG Knowledge Base UI
// 문서 관리 + 질문 입력 + 답변 표시

import { useState, useEffect, useCallback } from 'react'
import { Box, TextField, IconButton, Tooltip, LinearProgress } from '@mui/material'
import AddIcon from '@mui/icons-material/Add'
import DeleteIcon from '@mui/icons-material/Delete'
import RefreshIcon from '@mui/icons-material/Refresh'
import SearchIcon from '@mui/icons-material/Search'
import SendIcon from '@mui/icons-material/Send'
import DescriptionIcon from '@mui/icons-material/Description'
import { MetalCard, PhosphorText, Led, PhysicalButton, ScreenPanel } from '@d3ro/ui/components/ds'
import { PageHeader, EmptyStateCard } from '../components/shared'
import { isImeComposingEvent } from '../utils/keyboard'
import { d3roPalette, d3roFontMono, d3roTypo } from '@d3ro/ui/theme'
import { useI18n } from '@d3ro/i18n'
import type { RAGDocument, RAGQueryResult, RAGIndexProgress } from '@d3ro/core/types'

export function KnowledgeBasePage(): React.ReactElement {
  const { t } = useI18n()
  const [documents, setDocuments] = useState<RAGDocument[]>([])
  const [loading, setLoading] = useState(true)
  const [query, setQuery] = useState('')
  const [querying, setQuerying] = useState(false)
  const [result, setResult] = useState<RAGQueryResult | null>(null)
  const [indexProgress, setIndexProgress] = useState<RAGIndexProgress | null>(null)
  const [adding, setAdding] = useState(false)
  const [addError, setAddError] = useState<string | null>(null)

  const loadDocuments = useCallback(async () => {
    setLoading(true)
    const resp = await window.electronAPI.rag.getDocuments()
    if (resp.success) setDocuments(resp.data)
    setLoading(false)
  }, [])

  useEffect(() => { loadDocuments() }, [loadDocuments])

  useEffect(() => {
    const unsubProgress = window.electronAPI.rag.onIndexProgress((data) => {
      setIndexProgress(data)
    })
    const unsubComplete = window.electronAPI.rag.onIndexComplete(() => {
      setIndexProgress(null)
      loadDocuments()
    })
    return () => { unsubProgress(); unsubComplete() }
  }, [loadDocuments])

  const handleAddDocument = useCallback(async () => {
    setAdding(true)
    setAddError(null)
    const resp = await window.electronAPI.rag.addDocument()
    setAdding(false)
    if (resp.success) {
      loadDocuments()
    } else {
      if (!resp.error.message.includes('cancelled')) {
        setAddError(resp.error.message)
      }
    }
  }, [loadDocuments])

  const handleRemoveDocument = useCallback(async (docId: string) => {
    await window.electronAPI.rag.removeDocument({ documentId: docId })
    loadDocuments()
  }, [loadDocuments])

  const handleReindex = useCallback(async (docId: string) => {
    await window.electronAPI.rag.reindex(docId)
  }, [])

  const handleQuery = useCallback(async () => {
    if (!query.trim()) return
    setQuerying(true)
    setResult(null)
    const resp = await window.electronAPI.rag.query({ query: query.trim() })
    if (resp.success) {
      setResult(resp.data)
    }
    setQuerying(false)
  }, [query])

  const handleQueryKeyDown = useCallback((e: React.KeyboardEvent) => {
    if (isImeComposingEvent(e)) return
    if (e.key === 'Enter' && !e.shiftKey) {
      e.preventDefault()
      handleQuery()
    }
  }, [handleQuery])

  return (
    <Box sx={{ maxWidth: 900, mx: 'auto', p: 4, pb: 8 }}>
      <PageHeader
        title={t('rag.title').toUpperCase()}
        action={
          <PhysicalButton size="small" onClick={handleAddDocument} disabled={adding}>
            <AddIcon sx={{ fontSize: 14, mr: 0.5 }} /> {adding ? t('rag.adding') : t('rag.addDocument')}
          </PhysicalButton>
        }
      />

      {/* 인덱싱 진행률 */}
      {indexProgress && (
        <MetalCard sx={{ mb: 2 }}>
          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1, mb: 1 }}>
            <Led color="amber" pulse />
            <PhosphorText variant="body">
              {t('rag.indexing')}: {indexProgress.fileName}
            </PhosphorText>
          </Box>
          <LinearProgress
            variant="determinate"
            value={indexProgress.percent}
            sx={{
              height: 4,
              borderRadius: 2,
              bgcolor: d3roPalette.bg.inset,
              '& .MuiLinearProgress-bar': { bgcolor: d3roPalette.accent.amber },
            }}
          />
          <PhosphorText variant="dim" sx={{ mt: 0.5 }}>
            {indexProgress.currentChunk}/{indexProgress.totalChunks}
          </PhosphorText>
        </MetalCard>
      )}

      {/* 에러 표시 */}
      {addError && (
        <MetalCard sx={{ mb: 2, border: `1px solid ${d3roPalette.tag.red}` }}>
          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
            <Led color="red" />
            <PhosphorText variant="body" sx={{ color: d3roPalette.tag.red }}>
              {addError}
            </PhosphorText>
          </Box>
        </MetalCard>
      )}

      {/* 추가 중 인디케이터 */}
      {adding && !indexProgress && (
        <MetalCard sx={{ mb: 2 }}>
          <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
            <Led color="amber" pulse />
            <PhosphorText variant="body">{t('rag.parsing')}</PhosphorText>
          </Box>
        </MetalCard>
      )}

      {/* 문서 목록 */}
      <PhosphorText variant="label" sx={{ mb: 1.5, display: 'block', color: d3roPalette.text.inactive }}>
        {t('rag.documents').toUpperCase()} ({documents.length})
      </PhosphorText>

      {documents.length === 0 && !loading ? (
        <EmptyStateCard message={t('rag.noDocuments')} />
      ) : (
        <Box sx={{ display: 'flex', flexDirection: 'column', gap: 1, mb: 3 }}>
          {documents.map((doc) => (
            <MetalCard key={doc.id}>
              <Box sx={{ display: 'flex', alignItems: 'center', gap: 2 }}>
                <DescriptionIcon sx={{ fontSize: 20, color: d3roPalette.text.inactive }} />
                <Box sx={{ flex: 1 }}>
                  <PhosphorText variant="body">{doc.fileName}</PhosphorText>
                  <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.5, mt: 0.25 }}>
                    <PhosphorText variant="dim">
                      {doc.fileType.toUpperCase()} · {doc.chunkCount} {t('rag.chunks')} ·
                    </PhosphorText>
                    <Led color={doc.indexed ? 'green' : 'amber'} size={6} />
                    <PhosphorText variant="dim">
                      {doc.indexed ? t('rag.indexed') : t('rag.pending')}
                    </PhosphorText>
                  </Box>
                </Box>
                <Tooltip title={t('rag.reindex')}>
                  <IconButton size="small" onClick={() => handleReindex(doc.id)}
                    sx={{ color: d3roPalette.text.inactive, '&:hover': { color: d3roPalette.accent.amber } }}>
                    <RefreshIcon sx={{ fontSize: 16 }} />
                  </IconButton>
                </Tooltip>
                <Tooltip title={t('common.delete')}>
                  <IconButton size="small" onClick={() => handleRemoveDocument(doc.id)}
                    sx={{ color: d3roPalette.text.inactive, '&:hover': { color: d3roPalette.tag.red } }}>
                    <DeleteIcon sx={{ fontSize: 16 }} />
                  </IconButton>
                </Tooltip>
              </Box>
            </MetalCard>
          ))}
        </Box>
      )}

      {/* 질문 입력 */}
      <PhosphorText variant="label" sx={{ mb: 1.5, display: 'block', color: d3roPalette.text.inactive }}>
        {t('rag.askQuestion').toUpperCase()}
      </PhosphorText>

      <MetalCard>
        <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
          <SearchIcon sx={{ fontSize: 20, color: d3roPalette.text.inactive }} />
          <TextField
            value={query}
            onChange={(e) => setQuery(e.target.value)}
            onKeyDown={handleQueryKeyDown}
            placeholder={t('rag.queryPlaceholder')}
            size="small"
            fullWidth
            sx={{
              '& .MuiOutlinedInput-root': {
                fontFamily: d3roFontMono,
                fontSize: d3roTypo.compact.size,
                bgcolor: d3roPalette.bg.inset,
                '& fieldset': { borderColor: d3roPalette.border.subtle },
                '&:hover fieldset': { borderColor: d3roPalette.accent.amber },
              },
              '& .MuiOutlinedInput-input': { color: d3roPalette.text.primary },
            }}
          />
          <IconButton onClick={handleQuery} disabled={!query.trim() || querying}
            sx={{ color: query.trim() ? d3roPalette.accent.amber : d3roPalette.text.inactive }}>
            <SendIcon sx={{ fontSize: 20 }} />
          </IconButton>
        </Box>
      </MetalCard>

      {/* 답변 */}
      {querying && (
        <Box sx={{ mt: 2, textAlign: 'center' }}>
          <Led color="amber" pulse />
          <PhosphorText variant="dim" sx={{ ml: 1 }}>{t('rag.searching')}</PhosphorText>
        </Box>
      )}

      {result && (
        <Box sx={{ mt: 2 }}>
          <ScreenPanel sx={{ p: 3 }}>
            <PhosphorText variant="body" sx={{ whiteSpace: 'pre-wrap', lineHeight: 1.8 }}>
              {result.answer}
            </PhosphorText>
          </ScreenPanel>

          {result.results.length > 0 && (
            <Box sx={{ mt: 2 }}>
              <PhosphorText variant="label" sx={{ color: d3roPalette.text.dimLabel, mb: 1, display: 'block' }}>
                {t('rag.sources').toUpperCase()}
              </PhosphorText>
              {result.results.slice(0, 3).map((r, i) => (
                <MetalCard key={i} sx={{ mb: 1 }}>
                  <PhosphorText variant="dim">
                    [{i + 1}] {r.fileName} ({Math.round(r.similarity * 100)}%)
                  </PhosphorText>
                  <PhosphorText variant="compact" sx={{ mt: 0.5, opacity: 0.7 }}>
                    {r.content.slice(0, 150)}...
                  </PhosphorText>
                </MetalCard>
              ))}
            </Box>
          )}
        </Box>
      )}
    </Box>
  )
}