/**
 * Resolves a module specifier against an import map
 * @param {string} specifier - The module specifier to resolve (bare specifier or absolute URL)
 * @param {Object} importMap - The import map object containing imports and scopes
 * @param {string} baseURL - The base URL for context (especially for scopes)
 * @returns {string} The resolved URL
 */
export default function resolveImportMap(specifier, importMap, baseURL) {

    // Check for exact matches first (most common case for bare specifiers)
    const lookup = importMap.imports[specifier];
    if (lookup) { return lookup; }
    
    const Scanner =(obj)=>
    {
        // Check for path prefix matches (longest first)
        const keys = Object.keys(obj)
        .filter(key => key.endsWith('/'))
        .sort((a, b) => b.length - a.length);
        for (const key of keys)
        {
            if (specifier.startsWith(key))
            {
                const remainder = specifier.slice(key.length);
                return obj[key] + remainder;
            }
        }
    }

    const scan = Scanner(importMap.imports);
    if (scan) {return scan}
    
    // Handle scopes if available
    if (importMap.scopes) {
        const scopeKeys = Object.keys(importMap.scopes).sort((a, b) => b.length - a.length);
        for (const scopeKey of scopeKeys)
        {
            if (specifier.startsWith(scopeKey))
            {
                const scopeImports = importMap.scopes[scopeKey];
                const scan = Scanner(scopeImports);
                if (scan) {return scan}
            }
        }
    }

    return specifier;
  }
  
  // Example usage for bare specifiers:
  function demonstrateOptimizedResolver() {
    const importMap = {
      "imports": {
        "lodash": "https://cdn.skypack.dev/lodash",
        "react": "https://cdn.skypack.dev/react",
        "lib/": "/node_modules/lib/",
        "components/": "/components/"
      },
      "scopes": {
        "/admin/": {
          "components/": "/admin-components/",
          "admin-utils": "scoped!/js/admin-utils.js"
        }
      }
    };
    
    // Examples with bare specifiers
    console.log("Resolving 'lodash':", resolveImportMap("lodash", importMap, "https://example.com/admin/dashboard/"));
    console.log("Resolving 'components/button':", resolveImportMap("components/button", importMap, "https://example.com/admin/dashboard/"));
    
    // Example with scope
    console.log("Resolving 'admin-utils':", 
      resolveImportMap("admin-utils", importMap, "https://example.com/admin/dashboard/"));

    console.log("Resolving '/admin/admin-utils':", 
        resolveImportMap("admin-utils", importMap, "https://example.com/admin/dashboard/"));
      
    // Example with URL
    console.log("Resolving 'https://example.com/external.js':", 
      resolveImportMap("https://example.com/external.js", importMap, "https://example.com/admin/dashboard/"));
  }
  
  demonstrateOptimizedResolver();