/* The imported knowledge library.
 *
 * M7 built every behaviour here and M8 owns how it reads
 * (`BROWSER-UX-SPEC.md` §46-52, §21-22 of the M8 brief). What changed is
 * presentation and vocabulary, not capability: the same imports, the same
 * classification, enable/disable, narrator-only, always-include, delete,
 * inspect and rebuild.
 *
 * **Nothing here renders imported text as HTML.** Source text and passage text
 * both go into a `<pre>` as React children, which React escapes — so a
 * `<script>` in a file is visible characters, a `javascript:` URL is never an
 * href, and a remote Markdown image reference creates no `<img>` and therefore
 * makes no request (H06, H07, G09). The safe Markdown renderer the transcript
 * uses is deliberately *not* used here: this panel exists to show a reader
 * exactly what is in their file, and rendering is the opposite of that.
 * `SECURITY-THREAT-MODEL.md` §14 names sanitized presentation text as the safer
 * default; rendering no markup at all is one step safer still.
 *
 * ## The classification is explained, not iconified
 *
 * §48 is explicit that the three classes must not rely on unexplained icons,
 * because the difference between them is the whole feature: it decides the
 * words a passage is framed with in the prompt, the weight it carries in
 * ranking, and which budget it competes in. The explanations are on the import
 * form where the decision is made, not in a tooltip.
 *
 * ## Semantic status
 *
 * §22. Three states have to be told apart and the inherited line ran them
 * together: searching by meaning is on; it is off because no embedding model is
 * configured, which is a supported setup; or a model *is* configured and is not
 * being used because M7 has no measured calibration for it, so retrieval
 * degraded to keyword-only. The third is the one that reads as a mysterious
 * failure if it is not explained, and it is the one M7's closeout added.
 *
 * No threshold is exposed. `0.58` is a measured property of one embedding
 * model, not a preference, and a slider over it would invite a reader to
 * recreate the defect M7's review found.
 */

import { useCallback, useEffect, useRef, useState } from 'react'
import { api } from '../../../api'
import { ConfirmDialog } from '../../../Dialog'

const CLASSES = [
  {
    value: 'canon',
    label: 'Canon',
    hint: 'Authoritative truth for this campaign. The narrator may not contradict it.',
  },
  {
    value: 'reference',
    label: 'Reference',
    hint: 'Supporting information. It informs description but does not establish story truth.',
  },
  {
    value: 'inspiration',
    label: 'Inspiration',
    hint: 'Creative and style influence only. Never a source of fact.',
  },
]

const CLASS_LABEL = Object.fromEntries(CLASSES.map((c) => [c.value, c.label]))

function bytes(n) {
  if (n < 1024) return `${n} B`
  if (n < 1024 * 1024) return `${(n / 1024).toFixed(1)} kB`
  return `${(n / 1024 / 1024).toFixed(2)} MB`
}

function when(iso) {
  if (!iso) return ''
  const d = new Date(iso)
  return Number.isNaN(d.getTime()) ? '' : d.toLocaleDateString()
}

/** The three classes, said in full. Shown where the choice is made. */
function ClassLegend() {
  return (
    <dl className="class-legend">
      {CLASSES.map((c) => (
        <div key={c.value}>
          <dt><span className={`class-tag class-${c.value}`}>{c.label}</span></dt>
          <dd>{c.hint}</dd>
        </div>
      ))}
    </dl>
  )
}

function SourceDetail({ advId, source, onError }) {
  const [detail, setDetail] = useState(null)
  const [chunks, setChunks] = useState(null)
  const [showText, setShowText] = useState(false)
  const [showChunks, setShowChunks] = useState(false)
  const [showAdvanced, setShowAdvanced] = useState(false)
  // The error reporter reaches this component through a ref rather than the
  // effect's dependencies. It arrives as a fresh arrow on every render of the
  // Play screen — which re-renders on every keystroke in the story box — so
  // depending on it would refetch the source once per character typed. Found by
  // M7's browser run; the ref keeps the *current* reporter without making it a
  // reason to re-run.
  const report = useRef(onError)
  report.current = onError

  useEffect(() => {
    let stale = false
    setDetail(null)
    api.getKnowledgeSource(advId, source.id)
      .then((r) => { if (!stale) setDetail(r) })
      .catch((e) => { if (!stale) report.current(e.message) })
    return () => { stale = true }
  }, [advId, source.id])

  const loadChunks = () => {
    setShowChunks((open) => !open)
    if (chunks === null) {
      api.getKnowledgeChunks(advId, source.id)
        .then(setChunks).catch((e) => report.current(e.message))
    }
  }

  return (
    <div className="knowledge-detail">
      <dl className="knowledge-facts">
        <div><dt>File</dt><dd>{source.original_filename}</dd></div>
        <div><dt>Imported</dt><dd>{when(source.imported_at)}</dd></div>
        <div><dt>Size</dt><dd>{bytes(source.byte_size)}</dd></div>
        <div>
          <dt>Passages</dt>
          <dd>{source.chunk_count} · {source.embedded_count} searchable by meaning</dd>
        </div>
      </dl>

      <div className="knowledge-detail-buttons">
        <button type="button" onClick={() => setShowText((open) => !open)}>
          {showText ? 'Hide the text' : 'Read the text'}
        </button>
        <button type="button" onClick={loadChunks}>
          {showChunks ? 'Hide passages' : `Show the ${source.chunk_count} passages`}
        </button>
      </div>

      {showText && (
        detail
          ? <pre className="knowledge-text" data-testid="knowledge-source-text">{detail.content}</pre>
          : <p className="dim">Loading…</p>
      )}

      {showChunks && (
        chunks
          ? chunks.map((chunk) => (
            <div key={chunk.id} className="knowledge-chunk">
              <div className="dim">
                passage {chunk.chunk_index + 1}
                {chunk.heading_path && ` · ${chunk.heading_path}`}
                {' '}· {chunk.token_count} tokens
                {chunk.embedded ? ' · searchable by meaning' : ' · keyword search only'}
              </div>
              <pre className="knowledge-text">{chunk.text}</pre>
            </div>
          ))
          : <p className="dim">Loading…</p>
      )}

      {/* §49's advanced half: the content identity and the parser versions. Of
          interest when comparing two copies of a file, and noise otherwise. */}
      <details className="knowledge-advanced" open={showAdvanced}
        onToggle={(e) => setShowAdvanced(e.currentTarget.open)}>
        <summary>Technical details</summary>
        <dl className="knowledge-facts">
          <div><dt>Type</dt><dd>{source.media_type}</dd></div>
          <div>
            <dt>Versions</dt>
            <dd>parser v{source.parser_version} · chunking v{source.chunking_version}</dd>
          </div>
        </dl>
        {/* In full rather than shortened: it is here to be compared against
            another copy, and half a digest compares nothing. */}
        <p className="knowledge-hash">SHA-256: {source.content_hash}</p>
      </details>
    </div>
  )
}

function SourceRow({ advId, source, open, onToggle, onChange, onDelete, onError }) {
  const [confirming, setConfirming] = useState(false)

  return (
    <li
      className={`knowledge-row ${source.enabled ? '' : 'disabled'}`}
      data-source-id={source.id}
      data-classification={source.classification}
    >
      <div className="knowledge-head">
        <button
          type="button"
          className="knowledge-title"
          aria-expanded={open}
          onClick={onToggle}
        >
          <span aria-hidden="true">{open ? '▾' : '▸'}</span> {source.title}
        </button>
        <span className={`class-tag class-${source.classification}`}>
          {CLASS_LABEL[source.classification]}
        </span>
        {!source.enabled && <span className="knowledge-badge">not in use</span>}
        {source.visibility === 'hidden' && (
          <span className="hidden-tag">narrator only</span>
        )}
        {source.always_include && <span className="knowledge-badge">always included</span>}
        {source.index_state === 'failed' && (
          <span className="knowledge-badge failed" title={source.index_detail}>
            could not be indexed
          </span>
        )}
        {source.embed_state === 'failed' && (
          <span className="knowledge-badge failed" title={source.embed_detail}>
            keyword search only
          </span>
        )}
      </div>

      <p className="knowledge-sub">
        {/* A title defaults to the filename without its extension, so two files
            differing only by type would otherwise look identical in the list. */}
        {source.original_filename && source.original_filename !== source.title && (
          <span>{source.original_filename} · </span>
        )}
        <span>imported {when(source.imported_at)}</span>
        <span> · {source.chunk_count} passage{source.chunk_count === 1 ? '' : 's'}</span>
      </p>

      <div className="knowledge-controls">
        <label>
          <span className="sr-only">Classification for {source.title}</span>
          <select
            value={source.classification}
            aria-label={`Classification for ${source.title}`}
            onChange={(e) => onChange(source, { classification: e.target.value })}
          >
            {CLASSES.map((c) => <option key={c.value} value={c.value}>{c.label}</option>)}
          </select>
        </label>
        <label>
          <input
            type="checkbox"
            checked={source.enabled}
            onChange={(e) => onChange(source, { enabled: e.target.checked })}
          />
          {' '}In use
        </label>
        <label>
          <input
            type="checkbox"
            checked={source.visibility === 'hidden'}
            onChange={(e) => onChange(source, {
              visibility: e.target.checked ? 'hidden' : 'normal',
            })}
          />
          {' '}Narrator only
        </label>
        {/* Canon's alone. The server enforces it too — this only stops the
            control offering something that would be silently ignored. */}
        {source.classification === 'canon' && (
          <label>
            <input
              type="checkbox"
              checked={source.always_include}
              onChange={(e) => onChange(source, { always_include: e.target.checked })}
            />
            {' '}Always include
          </label>
        )}
        <button type="button" className="danger" onClick={() => setConfirming(true)}>
          Delete
        </button>
      </div>

      {open && <SourceDetail advId={advId} source={source} onError={onError} />}

      {confirming && (
        <ConfirmDialog
          title={`Delete “${source.title}”?`}
          confirmLabel="Delete this source"
          destructive
          onCancel={() => setConfirming(false)}
          onConfirm={() => { setConfirming(false); onDelete(source) }}
        >
          <p>
            It stops being used from now on, and the story will no longer draw
            on it.
          </p>
          <p>
            Turns that already used it are unchanged — each one keeps its own
            record of what the narrator was given.
          </p>
          <p className="dim">
            If you only want to stop using it for a while, turn off “In use”
            instead. That is reversible.
          </p>
        </ConfirmDialog>
      )}
    </li>
  )
}

/** §22, in three cases rather than a boolean. */
function SemanticStatus({ status }) {
  if (!status) return null
  const model = status.embedding_model
  if (status.semantic_enabled) {
    return (
      <p className="dim" data-testid="semantic-status" data-state="on">
        Searching by keyword and by meaning.
        {status.pending_embeddings > 0
          && ` ${status.pending_embeddings} passage(s) are still being prepared.`}
      </p>
    )
  }
  if (!model) {
    return (
      <p className="dim" data-testid="semantic-status" data-state="lexical-only">
        Searching by keyword. Setting a <em>model for meaning-based search</em> in
        Settings would let it search by meaning as well — keyword search alone is
        a supported setup, and it is what finds names and invented terms.
      </p>
    )
  }
  // Configured but not calibrated: the M7 closeout case.
  return (
    <p className="notice-detail" data-testid="semantic-status" data-state="uncalibrated">
      Searching by keyword only. <code>{model}</code>, the model set for
      meaning-based search, has not been measured for this in this build, so it
      is not used to decide what is relevant — borrowing another model’s
      measurement would let unrelated material through. Keyword search is
      unaffected.
      {status.calibrated_models?.length > 0 && (
        <> Measured so far: {status.calibrated_models.join(', ')}.</>
      )}
    </p>
  )
}

const NO_OP = () => {}

function KnowledgePanel({ advId, refreshKey, onError, focusSourceId }) {
  const [sources, setSources] = useState(null)
  const [status, setStatus] = useState(null)
  const [file, setFile] = useState(null)
  const [classification, setClassification] = useState('canon')
  const [title, setTitle] = useState('')
  const [hidden, setHidden] = useState(false)
  const [busy, setBusy] = useState(false)
  const [notice, setNotice] = useState(null)
  const [duplicate, setDuplicate] = useState(null)
  const [openId, setOpenId] = useState(null)

  const load = useCallback(() => {
    api.listKnowledge(advId).then(setSources).catch(() => setSources([]))
    api.getKnowledgeStatus(advId).then(setStatus).catch(() => setStatus(null))
  }, [advId])

  useEffect(() => { load() }, [load, refreshKey])

  // Opened from a retrieved passage in the Context panel (§57).
  useEffect(() => {
    if (focusSourceId != null) setOpenId(focusSourceId)
  }, [focusSourceId])

  const doImport = async (allowDuplicate = false) => {
    if (!file) return
    setBusy(true)
    setNotice(null)
    try {
      await api.importKnowledge(advId, file, {
        classification,
        title,
        visibility: hidden ? 'hidden' : 'normal',
        allow_duplicate: allowDuplicate,
      })
      setFile(null)
      setTitle('')
      setDuplicate(null)
      // A file input cannot be controlled, so it is cleared through the DOM.
      // Without this, re-picking the same file after a failed import fires no
      // change event and the button does nothing.
      const input = document.getElementById('knowledge-file')
      if (input) input.value = ''
      setNotice('Imported.')
      load()
    } catch (err) {
      if (err.conflict) setDuplicate(err.conflict)
      setNotice(err.message)
    } finally {
      setBusy(false)
    }
  }

  const change = async (source, data) => {
    try {
      const updated = await api.updateKnowledgeSource(advId, source.id, data)
      setSources((prev) => prev.map((s) => (s.id === source.id ? updated : s)))
    } catch (err) { onError?.(err.message) }
  }

  const remove = async (source) => {
    try {
      await api.deleteKnowledgeSource(advId, source.id)
      setSources((prev) => prev.filter((s) => s.id !== source.id))
      load()
    } catch (err) { onError?.(err.message) }
  }

  const reindex = async () => {
    setBusy(true)
    setNotice(null)
    try {
      const out = await api.reindexKnowledge(advId)
      setNotice(
        `Rebuilt ${out.chunks} passage${out.chunks === 1 ? '' : 's'} across `
        + `${out.sources} source${out.sources === 1 ? '' : 's'}`
        + (out.semantic ? `, ${out.embedded} searchable by meaning.` : '.'),
      )
      load()
    } catch (err) {
      setNotice(err.message)
    } finally { setBusy(false) }
  }

  return (
    <div className="knowledge-panel">
      <p className="dim">
        Local <code>.txt</code> and <code>.md</code> files this campaign can draw
        on. Nothing is uploaded anywhere, no link in a file is ever followed, and
        text in a file is never treated as an instruction to the application.
      </p>

      <details className="knowledge-import-block" open={sources?.length === 0}>
        <summary>Import a file</summary>
        <div className="knowledge-import">
          <div className="field">
            <label htmlFor="knowledge-file">Choose a file</label>
            <input
              id="knowledge-file"
              type="file"
              accept=".txt,.md,text/plain,text/markdown"
              onChange={(e) => { setFile(e.target.files?.[0] || null); setDuplicate(null) }}
            />
          </div>

          <fieldset className="knowledge-class-choice">
            <legend>How should the story treat it?</legend>
            {CLASSES.map((c) => (
              <label key={c.value} className="class-choice">
                <input
                  type="radio"
                  name="knowledge-class"
                  value={c.value}
                  checked={classification === c.value}
                  onChange={() => setClassification(c.value)}
                />
                <span className={`class-tag class-${c.value}`}>{c.label}</span>
                <span className="class-choice-hint">{c.hint}</span>
              </label>
            ))}
          </fieldset>

          <div className="field">
            <label htmlFor="knowledge-title">Title (optional)</label>
            <input
              id="knowledge-title"
              type="text"
              value={title}
              placeholder="Defaults to the filename"
              onChange={(e) => setTitle(e.target.value)}
            />
          </div>

          <label className="knowledge-hidden-choice">
            <input
              type="checkbox"
              checked={hidden}
              onChange={(e) => setHidden(e.target.checked)}
            />
            {' '}Narrator only — the narrator knows it, your character does not
          </label>

          <button
            type="button"
            className="primary"
            id="knowledge-import"
            disabled={!file || busy}
            onClick={() => doImport(false)}
          >
            {busy ? 'Working…' : 'Import file'}
          </button>
        </div>
      </details>

      {notice && <div className="knowledge-notice" id="knowledge-notice">{notice}</div>}
      {duplicate && (
        <div className="knowledge-notice">
          Already imported as “{duplicate.title}” ({CLASS_LABEL[duplicate.classification]}).{' '}
          <button type="button" onClick={() => doImport(true)}>
            Import a second copy anyway
          </button>
        </div>
      )}

      {status && (
        <div className="knowledge-status">
          <SemanticStatus status={status} />
          {status.failed_index.length > 0 && (
            <p className="notice-detail error">
              {status.failed_index.length} file(s) could not be indexed and cannot
              be found by search.
            </p>
          )}
          {status.failed_embedding.length > 0 && (
            <p className="notice-detail">
              {status.failed_embedding.length} file(s) could not be prepared for
              meaning-based search. Keyword search still finds them.
            </p>
          )}
        </div>
      )}

      <div className="knowledge-list-head">
        <h3>In this campaign {sources && `(${sources.length})`}</h3>
        <button
          type="button"
          onClick={reindex}
          disabled={busy}
          title="Rebuild passages and search indexes from the stored text. Your story is untouched."
        >
          Rebuild search
        </button>
      </div>

      {!sources && <p className="dim">Loading…</p>}
      {sources && sources.length === 0 && (
        <div className="knowledge-empty">
          <p>Nothing imported yet.</p>
          <p className="dim">
            A setting bible, character notes, a research file, or a passage whose
            style you want the prose to feel like.
          </p>
          <ClassLegend />
        </div>
      )}
      {sources?.length > 0 && (
        <ul className="knowledge-list">
          {sources.map((source) => (
            <SourceRow
              key={source.id}
              advId={advId}
              source={source}
              open={openId === source.id}
              onToggle={() => setOpenId(openId === source.id ? null : source.id)}
              onChange={change}
              onDelete={remove}
              onError={onError || NO_OP}
            />
          ))}
        </ul>
      )}
    </div>
  )
}

export { KnowledgePanel, ClassLegend, SemanticStatus, CLASSES, CLASS_LABEL }