import type { Skill } from "./types.js";

export function formatSkillsForSystemPrompt(skills: Skill[]): string {
  const visibleSkills = skills.filter((skill) => !skill.disableModelInvocation);
  if (visibleSkills.length === 0) {
    return "";
  }

  const lines = [
    "The following skills provide specialized instructions for specific tasks.",
    "Read the full skill file when the task matches its description.",
    "When a skill file references a relative path, resolve it against the skill directory (parent of SKILL.md / dirname of the path) and use that absolute path in tool commands.",
    "",
    "<available_skills>",
  ];

  for (const skill of visibleSkills) {
    lines.push("  <skill>");
    lines.push(`    <name>${escapeXml(skill.name)}</name>`);
    lines.push(`    <description>${escapeXml(skill.description)}</description>`);
    lines.push(`    <location>${escapeXml(skill.filePath)}</location>`);
    lines.push("  </skill>");
  }

  lines.push("</available_skills>");
  return lines.join("\n");
}

function escapeXml(value: string): string {
  return value
    .replace(/&/g, "&amp;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&apos;");
}