//c#
///////////////////////////////////////////////////////////////////////////
//  Copyright (C) Wizardry and Steamworks 2011 - License: GNU GPLv3      //
//  Please see: http://www.gnu.org/licenses/gpl.html for legal details,  //
//  rights of fair usage, the disclaimer and warranty conditions.        //
///////////////////////////////////////////////////////////////////////////

string DOCUMENT_PATH = @"/home/opensim/books/";
string filesHash = "";

public void default_event_state_entry() {
    DOCUMENT_PATH += llGetObjectDesc();
    llSetTimerEvent(5.0);
}

public void default_event_timer() {
    System.Collections.Generic.List<string> path = new System.Collections.Generic.List<string>(System.IO.Directory.GetFiles(DOCUMENT_PATH));
    // If no documents are available, skip.
    if(path.Count == 0) return;
    string hash = CalculateMD5Hash(string.Join("", path.ToArray()));
    // If the last known MD5 hash is different from the newly computed hash, skip.
    if(hash == filesHash) return;
    // Save the hash since the file listing has changed.
    filesHash = hash;

    // Remove all notecards in inventory or skip if none available.
    LSL_Types.LSLInteger cards = llGetInventoryNumber(INVENTORY_NOTECARD)-1;
    if(cards == -1) goto Import;
    do {
        llRemoveInventory(llGetInventoryName(INVENTORY_NOTECARD, cards));
    } while(--cards>-1);

Import:
    foreach(string file in path) {
        string notecardName = System.IO.Path.GetFileName(file);
        // If notecard exists, skip.
        if(llGetInventoryType(notecardName) == INVENTORY_NOTECARD) continue;
        // Skip UNIX dot-files.
        if(llGetSubString(notecardName, 0, 0) == ".") continue;
        // Attempt to read file, skip if not possible.
        string data = "";
        try {
            data = System.IO.File.ReadAllText(file);
        } 
        catch(System.Exception) {
            // If file could not be read, for any reason, skip.
            continue;
        }
        // Create the notecard.
        osMakeNotecard(notecardName, (LSL_Types.LSLString) data);
    }

}

//http://blogs.msdn.com/b/csharpfaq/archive/2006/10/09/how-do-i-calculate-a-md5-hash-from-a-string_3f00_.aspx
private string CalculateMD5Hash(string input) {
    System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create();
    byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
    byte[] hash = md5.ComputeHash(inputBytes);
    System.Text.StringBuilder sb = new System.Text.StringBuilder();
    for (int i = 0; i < hash.Length; i++)
    {
        sb.Append(hash[i].ToString("X2"));
    }
    return sb.ToString();
}