| 1 | import { useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState } from "react"; |
| 2 | import type { ReactNode } from "react"; |
| 3 | import { Command, Search } from "lucide-react"; |
| 4 | import { useT } from "../lib/i18n"; |
| 5 | import { useMountTransition } from "../lib/useMountTransition"; |
| 6 | |
| 7 | // CommandPalette is a ⌘K / Ctrl+K modal that surfaces the desktop app's |
| 8 | // long-tail navigation surface. Tabs through sessions, slash-commands, and |
| 9 | // recent files via a single fuzzy search. The list of items is provided by |
| 10 | // the caller (App) so the palette stays decoupled from the controller — the |
| 11 | // same component will work for skills, MCP servers, and future surfaces |
| 12 | // once a buildItems() helper is added for them. |
| 13 | // |
| 14 | // Interaction model: |
| 15 | // - Input is auto-focused on open; the first match is highlighted. |
| 16 | // - ↑/↓ move the highlight (wraps at the edges). |
| 17 | // - Enter runs the highlighted item's action. |
| 18 | // - Esc closes. |
| 19 | // - Mouse hover sets the highlight (so a click can be "pre-thought"); the |
| 20 | // click itself runs the action. |
| 21 | // |
| 22 | // Fuzzy match is a small case-insensitive substring scorer — every query |
| 23 | // token must appear in the candidate's title or hint, in order, but they |
| 24 | // may overlap (a real fuzzy matcher would be overkill for 50-200 items). |
| 25 | export interface PaletteItem { |
| 26 | // id is stable and unique within a single open of the palette. |
| 27 | id: string; |
| 28 | // title is the primary label. |
| 29 | title: string; |
| 30 | // hint is the secondary line (a path, a command's source, etc.). |
| 31 | hint?: string; |
| 32 | // meta is right-aligned secondary text (e.g. a timestamp). |
| 33 | meta?: string; |
| 34 | // badge is a right-aligned counter or label (e.g. turn count). |
| 35 | badge?: string; |
| 36 | // icon overrides the default Command icon shown on the left. |
| 37 | icon?: ReactNode; |
| 38 | // compact renders the item as a grid chip (icon + title, no hint/meta). |
| 39 | compact?: boolean; |
| 40 | // group is the section header this item belongs to. |
| 41 | group: string; |
| 42 | // keywords add to the searchable text (e.g. slash-command aliases). |
| 43 | keywords?: string[]; |
| 44 | // run closes the palette and dispatches the action. |
| 45 | run: () => void | Promise<void>; |
| 46 | } |
| 47 | |
| 48 | export function CommandPalette({ |
| 49 | open, |
| 50 | onClose, |
| 51 | items, |
| 52 | placeholder, |
| 53 | emptyText, |
| 54 | }: { |
| 55 | open: boolean; |
| 56 | onClose: () => void; |
| 57 | items: PaletteItem[]; |
| 58 | placeholder: string; |
| 59 | emptyText: string; |
| 60 | }) { |
| 61 | const t = useT(); |
| 62 | const [query, setQuery] = useState(""); |
| 63 | const [active, setActive] = useState(-1); |
| 64 | const inputRef = useRef<HTMLInputElement>(null); |
| 65 | const isOpenRef = useRef(false); |
| 66 | isOpenRef.current = open; |
| 67 | // Keep the palette mounted through its exit animation after `open` flips |
| 68 | // false; `status` drives the enter/exit keyframes via data-state. |
| 69 | const { mounted, status } = useMountTransition(open, 200); |
| 70 | |
| 71 | // Re-init whenever the palette opens: clear the query, reset the |
| 72 | // highlight, and steal focus. Doing it on the open edge (not on every |
| 73 | // render) means a previously-typed query doesn't leak across opens. |
| 74 | // useLayoutEffect fires synchronously after DOM mutations, before the |
| 75 | // browser paints — ensures focus lands before any paint-time transitions |
| 76 | // can interfere. |
| 77 | useLayoutEffect(() => { |
| 78 | if (open) { |
| 79 | setQuery(""); |
| 80 | setActive(items.length > 0 ? 0 : -1); |
| 81 | inputRef.current?.focus(); |
| 82 | } |
| 83 | }, [open, items.length]); |
| 84 | |
| 85 | // Callback ref: when the input element mounts while the palette is open, |
| 86 | // focus it immediately. This handles the case where the DOM element |
| 87 | // becomes available after the useLayoutEffect already ran. |
| 88 | const inputCallbackRef = useCallback( |
| 89 | (el: HTMLInputElement | null) => { |
| 90 | inputRef.current = el; |
| 91 | if (el && isOpenRef.current) el.focus(); |
| 92 | }, |
| 93 | [], |
| 94 | ); |
| 95 | |
| 96 | // score is the fuzzy match: every space-separated query token must |
| 97 | // appear (case-insensitively) in the candidate's haystack, in the order |
| 98 | // given. The score is the sum of the inverse lengths of the matching |
| 99 | // substrings (smaller span → higher rank) so a tight prefix match wins |
| 100 | // over a spread match. |
| 101 | const filtered = useMemo(() => { |
| 102 | const q = query.trim().toLowerCase(); |
| 103 | if (!q) return items; |
| 104 | const tokens = q.split(/\s+/); |
| 105 | const scored: { item: PaletteItem; score: number }[] = []; |
| 106 | for (const it of items) { |
| 107 | const hay = [it.title, it.hint ?? "", ...(it.keywords ?? [])].join("\n").toLowerCase(); |
| 108 | let cursor = 0; |
| 109 | let score = 0; |
| 110 | let ok = true; |
| 111 | for (const tok of tokens) { |
| 112 | const at = hay.indexOf(tok, cursor); |
| 113 | if (at < 0) { |
| 114 | ok = false; |
| 115 | break; |
| 116 | } |
| 117 | // Reward tight matches (smaller span) and matches early in the string. |
| 118 | score += 1000 - (at - cursor) - at; |
| 119 | cursor = at + tok.length; |
| 120 | } |
| 121 | if (ok) scored.push({ item: it, score }); |
| 122 | } |
| 123 | scored.sort((a, b) => b.score - a.score); |
| 124 | return scored.map((s) => s.item); |
| 125 | }, [query, items]); |
| 126 | |
| 127 | // Group the filtered items by their `group` field, preserving the order |
| 128 | // the groups first appear (so a "Sessions" group with a hit is shown |
| 129 | // before a "Commands" group with a hit, even if the commands' raw |
| 130 | // scores would outrank it). This matches the user's mental model: |
| 131 | // sessions are the most frequent target. |
| 132 | const grouped = useMemo(() => { |
| 133 | const out: { group: string; items: PaletteItem[] }[] = []; |
| 134 | const indexOf = (g: string) => out.findIndex((o) => o.group === g); |
| 135 | for (const it of filtered) { |
| 136 | const at = indexOf(it.group); |
| 137 | if (at < 0) out.push({ group: it.group, items: [it] }); |
| 138 | else out[at].items.push(it); |
| 139 | } |
| 140 | return out; |
| 141 | }, [filtered]); |
| 142 | |
| 143 | // Flat index -> grouped item lookup. The keyboard handler only needs |
| 144 | // the linear index, so we keep a parallel array to avoid a quadratic |
| 145 | // walk on every keypress. |
| 146 | const flat = useMemo(() => grouped.flatMap((g) => g.items), [grouped]); |
| 147 | |
| 148 | // Clamp the active index whenever the result set shrinks (e.g. user |
| 149 | // typed something that filtered out the previously-highlighted item). |
| 150 | useEffect(() => { |
| 151 | if (active >= 0 && active >= flat.length) setActive(Math.max(0, flat.length - 1)); |
| 152 | }, [flat.length, active]); |
| 153 | |
| 154 | // Reset the highlight to the first match on every query change — the user |
| 155 | // just refined their search, the old highlight is rarely still interesting. |
| 156 | useEffect(() => { |
| 157 | setActive(0); |
| 158 | }, [query]); |
| 159 | |
| 160 | // Esc closes; ↑/↓ move the highlight; Enter runs. We use a document-level |
| 161 | // listener so the palette is responsive even when focus drifts (e.g. the |
| 162 | // user clicks a result row, then presses ↑). |
| 163 | useEffect(() => { |
| 164 | if (!open) return; |
| 165 | const onKey = (e: KeyboardEvent) => { |
| 166 | const closeButtonHasFocus = e.target instanceof HTMLElement && Boolean(e.target.closest("[data-palette-close]")); |
| 167 | if (closeButtonHasFocus && (e.key === "Enter" || e.key === " ")) return; |
| 168 | if (e.key === "Escape") { |
| 169 | e.preventDefault(); |
| 170 | onClose(); |
| 171 | return; |
| 172 | } |
| 173 | if (e.key === "ArrowDown") { |
| 174 | e.preventDefault(); |
| 175 | setActive((i) => (flat.length === 0 ? -1 : i < 0 ? 0 : (i + 1) % flat.length)); |
| 176 | return; |
| 177 | } |
| 178 | if (e.key === "ArrowUp") { |
| 179 | e.preventDefault(); |
| 180 | setActive((i) => (flat.length === 0 ? -1 : i <= 0 ? flat.length - 1 : i - 1)); |
| 181 | return; |
| 182 | } |
| 183 | if (e.key === "Enter") { |
| 184 | e.preventDefault(); |
| 185 | const it = flat[active]; |
| 186 | if (it) void it.run(); |
| 187 | onClose(); |
| 188 | return; |
| 189 | } |
| 190 | }; |
| 191 | document.addEventListener("keydown", onKey); |
| 192 | return () => document.removeEventListener("keydown", onKey); |
| 193 | }, [open, flat, active, onClose]); |
| 194 | |
| 195 | if (!mounted) return null; |
| 196 | |
| 197 | // The running counter maps a flat-index back to its group header so we |
| 198 | // can render the section dividers in order. |
| 199 | let running = 0; |
| 200 | |
| 201 | return ( |
| 202 | <div |
| 203 | className="drawer-backdrop" |
| 204 | data-state={status} |
| 205 | onClick={onClose} |
| 206 | role="presentation" |
| 207 | > |
| 208 | <div className="palette" data-state={status} onClick={(e) => e.stopPropagation()} role="dialog" aria-modal="true" aria-label={placeholder}> |
| 209 | <div className="palette__inputrow"> |
| 210 | <Search className="palette__search-icon" size={18} aria-hidden="true" /> |
| 211 | <input |
| 212 | ref={inputCallbackRef} |
| 213 | className="palette__input" |
| 214 | value={query} |
| 215 | onChange={(e) => setQuery(e.target.value)} |
| 216 | placeholder={placeholder} |
| 217 | spellCheck={false} |
| 218 | autoComplete="off" |
| 219 | /> |
| 220 | <button |
| 221 | className="palette__esc" |
| 222 | type="button" |
| 223 | onClick={onClose} |
| 224 | aria-label={t("common.close")} |
| 225 | title={t("common.close")} |
| 226 | data-palette-close |
| 227 | > |
| 228 | esc |
| 229 | </button> |
| 230 | </div> |
| 231 | <div className="palette__list" role="listbox"> |
| 232 | {flat.length === 0 ? ( |
| 233 | <div className="palette__empty">{emptyText}</div> |
| 234 | ) : ( |
| 235 | grouped.map((g) => { |
| 236 | const isCompact = g.items[0]?.compact; |
| 237 | return ( |
| 238 | <div className={`palette__group ${isCompact ? "palette__group--grid" : ""}`} key={g.group}> |
| 239 | <div className="palette__group-title">{g.group}</div> |
| 240 | {isCompact ? ( |
| 241 | <div className="palette__grid"> |
| 242 | {g.items.map((it) => { |
| 243 | const idx = running++; |
| 244 | const on = idx === active; |
| 245 | return ( |
| 246 | <button |
| 247 | type="button" |
| 248 | role="option" |
| 249 | aria-selected={on} |
| 250 | key={it.id} |
| 251 | className={`palette__chip ${on ? "palette__chip--on" : ""}`} |
| 252 | onMouseEnter={() => setActive(idx)} |
| 253 | onClick={() => { |
| 254 | void it.run(); |
| 255 | onClose(); |
| 256 | }} |
| 257 | > |
| 258 | <span className="palette__chip-icon" aria-hidden="true"> |
| 259 | {it.icon ?? <Command size={15} />} |
| 260 | </span> |
| 261 | <span className="palette__chip-label">{it.title}</span> |
| 262 | </button> |
| 263 | ); |
| 264 | })} |
| 265 | </div> |
| 266 | ) : ( |
| 267 | g.items.map((it) => { |
| 268 | const idx = running++; |
| 269 | const on = idx === active; |
| 270 | return ( |
| 271 | <button |
| 272 | type="button" |
| 273 | role="option" |
| 274 | aria-selected={on} |
| 275 | key={it.id} |
| 276 | className={`palette__item ${on ? "palette__item--on" : ""}`} |
| 277 | onMouseEnter={() => setActive(idx)} |
| 278 | onClick={() => { |
| 279 | void it.run(); |
| 280 | onClose(); |
| 281 | }} |
| 282 | > |
| 283 | <span className="palette__item-icon" aria-hidden="true"> |
| 284 | {it.icon ?? <Command size={15} />} |
| 285 | </span> |
| 286 | <span className="palette__body"> |
| 287 | <span className="palette__title">{it.title}</span> |
| 288 | {(it.hint || it.meta || it.badge) && ( |
| 289 | <span className="palette__hint"> |
| 290 | {it.hint && <span className="palette__hint-text">{it.hint}</span>} |
| 291 | {it.meta && <span className="palette__meta">{it.meta}</span>} |
| 292 | {it.badge && <span className="palette__badge">{it.badge}</span>} |
| 293 | </span> |
| 294 | )} |
| 295 | </span> |
| 296 | </button> |
| 297 | ); |
| 298 | }) |
| 299 | )} |
| 300 | </div> |
| 301 | ); |
| 302 | }) |
| 303 | )} |
| 304 | </div> |
| 305 | <div className="palette__foot"> |
| 306 | <span> |
| 307 | <kbd>↑</kbd> |
| 308 | <kbd>↓</kbd> navigate |
| 309 | </span> |
| 310 | <span> |
| 311 | <kbd>↵</kbd> run |
| 312 | </span> |
| 313 | <span> |
| 314 | <kbd>esc</kbd> close |
| 315 | </span> |
| 316 | </div> |
| 317 | </div> |
| 318 | </div> |
| 319 | ); |
| 320 | } |
| 321 |