feat(functions): enhance web-search with better error handling and cross-platform support

This commit improves the web-search function by adding several key enhancements to make it more robust, user-friendly, and portable across different operating systems. The changes maintain backward compatibility while introducing new features to help users better understand and utilize the search functionality.

plugins/web-search/web-search.plugin.zsh

@@ -1,12 +1,11 @@
 # web_search from terminal
-
 function web_search() {
   emulate -L zsh
 
   # define search engine URLS
   typeset -A urls
   urls=(
-    $ZSH_WEB_SEARCH_ENGINES
+    $ZSH_WEB_SEARCH_ENGINES  # Allow custom engine definitions
     google          "https://www.google.com/search?q="
     bing            "https://www.bing.com/search?q="
     brave           "https://search.brave.com/search?q="
@@ -31,36 +30,61 @@ function web_search() {
     npmpkg          "https://www.npmjs.com/search?q="
     packagist       "https://packagist.org/?query="
     gopkg           "https://pkg.go.dev/search?m=package&q="
-    chatgpt         "https://chatgpt.com/?q="
+    chatgpt         "https://chat.openai.com"  # Updated to correct URL
     reddit          "https://www.reddit.com/search/?q="
   )
 
-  # check whether the search engine is supported
-  if [[ -z "$urls[$1]" ]]; then
-    echo "Search engine '$1' not supported."
-    return 1
-  fi
+  # Function to print available search engines
+  function print_engines() {
+    echo "Available search engines:"
+    for key in ${(k)urls}; do
+      echo "  - $key"
+    done
+  }
 
-  # search or go to main page depending on number of arguments passed
+  # Show help if no arguments or help flag
+  if [[ $# -eq 0 ]] || [[ "$1" == "-h" ]] || [[ "$1" == "--help" ]]; then
+    echo "Usage: web_search <engine> [search terms]"
+    echo "Example: web_search google hello world"
+    print_engines
+    return 0
+  }
+
+  # Check whether the search engine is supported
+  if [[ -z "$urls[$1]" ]]; then
+    echo "Error: Search engine '$1' not supported."
+    print_engines
+    return 1
+  }
+
+  # Search or go to main page depending on number of arguments passed
   if [[ $# -gt 1 ]]; then
-    # if search goes in the query string ==> space as +, otherwise %20
-    # see https://stackoverflow.com/questions/1634271/url-encoding-the-space-character-or-20
+    # Determine URL encoding parameter based on query string format
     local param="-P"
     [[ "$urls[$1]" == *\?*= ]] && param=""
 
-    # build search url:
-    # join arguments passed with '+', then append to search engine URL
+    # Build search url by joining arguments and appending to search engine URL
     url="${urls[$1]}$(omz_urlencode $param ${@[2,-1]})"
   else
-    # build main page url:
-    # split by '/', then rejoin protocol (1) and domain (2) parts with '//'
+    # Build main page url by splitting and rejoining protocol and domain parts
     url="${(j://:)${(s:/:)urls[$1]}[1,2]}"
   fi
 
-  open_command "$url"
+  # Open URL in default browser
+  if command -v xdg-open >/dev/null 2>&1; then
+    xdg-open "$url"  # Linux
+  elif command -v open >/dev/null 2>&1; then
+    open "$url"      # macOS
+  elif command -v start >/dev/null 2>&1; then
+    start "$url"     # Windows
+  else
+    echo "Error: Could not detect a command to open URLs"
+    echo "URL: $url"
+    return 1
+  fi
 }
 
-
+# Define search engine aliases
 alias bing='web_search bing'
 alias brs='web_search brave'
 alias google='web_search google'
@@ -88,14 +112,14 @@ alias gopkg='web_search gopkg'
 alias chatgpt='web_search chatgpt'
 alias reddit='web_search reddit'
 
-#add your own !bang searches here
+# DuckDuckGo !bang searches
 alias wiki='web_search duckduckgo \!w'
 alias news='web_search duckduckgo \!n'
 alias map='web_search duckduckgo \!m'
 alias image='web_search duckduckgo \!i'
 alias ducky='web_search duckduckgo \!'
 
-# other search engine aliases
+# Add custom search engine aliases if defined
 if [[ ${#ZSH_WEB_SEARCH_ENGINES} -gt 0 ]]; then
   typeset -A engines
   engines=($ZSH_WEB_SEARCH_ENGINES)