/** Tool icons for the sidebar's command fragment (docs/SIDEBAR.md).
 *
 * A session's command line starts with the program that runs it, and that
 * program is nearly always one of a handful of agents or a shell. Rendering it
 * as its own mark buys back the whole fragment's width — the arguments are
 * dropped, so a card says which tool runs, not how it was invoked.
 *
 * Recognition is deliberately narrow: an unrecognised program keeps its name
 * as text, so the fragment never renders a mark that stands for the wrong tool.
 */

/** Command wrappers that run another program: the tool is what follows. */
const WRAPPERS = new Set(["sudo", "env", "npx", "bunx", "uvx", "pnpm", "yarn", "command"]);

/** Program name (already basenamed and lowercased) → icon id. */
const BY_PROGRAM: Record<string, string> = {
  claude: "claude",
  "claude-code": "claude",
  codex: "codex",
  opencode: "opencode",
  gemini: "gemini",
  aider: "aider",
  cursor: "cursor",
  "cursor-agent": "cursor",
  pi: "pi",
  bash: "shell",
  zsh: "shell",
  sh: "shell",
  fish: "shell",
  dash: "shell",
  ksh: "shell",
  nu: "shell",
  xonsh: "shell",
};

/** Human name behind an icon id, for the tooltip and the aria label. */
export const TOOL_LABELS: Record<string, string> = {
  claude: "Claude Code",
  codex: "Codex",
  opencode: "opencode",
  gemini: "Gemini CLI",
  aider: "Aider",
  cursor: "Cursor",
  pi: "pi",
  shell: "Shell",
};

export interface CommandParts {
  /** Icon id, or `null` when the program is not one we have a mark for. */
  tool: string | null;
  /** The program the command runs, basenamed and stripped of its arguments —
   * what a card shows when there is no icon to show instead. */
  program: string;
}

/** Split a command line into the tool its icon stands for and the program name.
 *
 * `claude --resume` → `{tool: "claude", program: "claude"}`; an unrecognised
 * `hx src/` keeps `hx` as the program with no tool. */
export function splitCommand(command: string): CommandParts {
  const words = command.trim().split(/\s+/).filter(Boolean);
  let i = 0;
  // Leading `FOO=bar` assignments and wrappers stand in front of the real
  // program; `pnpm dlx x` / `yarn dlx x` need one more word skipped.
  while (i < words.length) {
    const word = words[i];
    if (/^[A-Za-z_][A-Za-z0-9_]*=/.test(word)) {
      i += 1;
      continue;
    }
    const wrapper = basename(word).toLowerCase();
    if (WRAPPERS.has(wrapper)) {
      i += 1;
      if ((wrapper === "pnpm" || wrapper === "yarn") && words[i] === "dlx") i += 1;
      continue;
    }
    break;
  }
  if (i >= words.length) return { tool: null, program: command.trim() };
  const program = basename(words[i]);
  return { tool: BY_PROGRAM[program.toLowerCase()] ?? null, program };
}

function basename(word: string): string {
  const cut = word.lastIndexOf("/");
  return cut >= 0 ? word.slice(cut + 1) : word;
}

/** Anthropic's burst: tapered rays around a centre, long ones on the axes. */
function burst(): string {
  const rays = Array.from({ length: 8 }, (_, k) => {
    const long = k % 2 === 0;
    const tip = long ? 1.1 : 3.4;
    const waist = long ? 6.3 : 6.6;
    const half = long ? 1.05 : 0.85;
    return `<path d="M8 ${tip} L${8 + half} ${waist} L8 8 L${8 - half} ${waist} Z" transform="rotate(${k * 45} 8 8)"/>`;
  }).join("");
  return `<g fill="#d97757">${rays}</g>`;
}

const SVGS: Record<string, string> = {
  claude: burst(),
  // A hexafoil knot in the shape of OpenAI's mark. The petals stay thin and
  // wide apart: three fatter loops merge into a blob at 13px.
  codex: `<g fill="none" stroke="currentColor" stroke-width="1.05">
    <ellipse cx="8" cy="8" rx="2.5" ry="6.7"/>
    <ellipse cx="8" cy="8" rx="2.5" ry="6.7" transform="rotate(60 8 8)"/>
    <ellipse cx="8" cy="8" rx="2.5" ry="6.7" transform="rotate(120 8 8)"/>
  </g>`,
  gemini: `<path fill="#4285f4" d="M8 0.8C8.6 4.6 11.4 7.4 15.2 8C11.4 8.6 8.6 11.4 8 15.2C7.4 11.4 4.6 8.6 0.8 8C4.6 7.4 7.4 4.6 8 0.8Z"/>`,
  // An isometric cube, the shape Cursor's mark is built from.
  cursor: `<g fill="currentColor">
    <path d="M8 1 L14.5 4.75 L8 8.5 L1.5 4.75 Z" opacity="0.95"/>
    <path d="M14.5 4.75 L14.5 12.25 L8 16 L8 8.5 Z" opacity="0.5"/>
    <path d="M1.5 4.75 L8 8.5 L8 16 L1.5 12.25 Z" opacity="0.75"/>
  </g>`,
  shell: `<g fill="none" stroke="currentColor" stroke-width="1.6" stroke-linecap="round" stroke-linejoin="round">
    <path d="M2.6 4 L6.4 8 L2.6 12"/>
    <path d="M8.4 12.6 H13.4"/>
  </g>`,
  opencode: monogram("oc"),
  aider: monogram("ai"),
  pi: monogram("π"),
};

/** Tools whose own mark is a wordmark get their initials instead — inventing
 * a logo for them would be worse than saying which letters they start with.
 * No chip around the letters: a border this small eats the height the letters
 * need to stay apart. */
function monogram(text: string): string {
  return `<text x="8" y="8.6" fill="currentColor" font-family="ui-monospace, SFMono-Regular, Menlo, monospace" font-size="11" font-weight="700" letter-spacing="-0.6" text-anchor="middle" dominant-baseline="central">${text}</text>`;
}

/** The `<svg>` for an icon id, or `null` when the id has no mark. */
export function toolIconSvg(tool: string): string | null {
  const body = SVGS[tool];
  if (!body) return null;
  const label = TOOL_LABELS[tool] ?? tool;
  return `<svg class="tool-icon" data-tool="${tool}" viewBox="0 0 16 16" width="13" height="13" role="img" aria-label="${label}"><title>${label}</title>${body}</svg>`;
}