namespace System.Web.UI {
    using System;
    using System.Collections.Concurrent;
    using System.Globalization;
    using System.Reflection;
    using System.Web.Resources;
    using System.Web.Util;

    public class ScriptResourceMapping : IScriptResourceMapping {
        private readonly ConcurrentDictionary<Tuple<String, Assembly>, ScriptResourceDefinition> _definitions =
            new ConcurrentDictionary<Tuple<String, Assembly>, ScriptResourceDefinition>();

        public void AddDefinition(string name, ScriptResourceDefinition definition) {
            AddDefinition(name, assembly: AssemblyCache.SystemWebExtensions, definition: definition);
        }

        public void AddDefinition(string name, Assembly assembly, ScriptResourceDefinition definition) {
            // dictionary indexer will update the value if it already exists
            if (String.IsNullOrEmpty(name)) {
                throw new ArgumentException(AtlasWeb.Common_NullOrEmpty, "name");
            }
            if (definition == null) {
                throw new ArgumentNullException("definition");
            }
            if (String.IsNullOrEmpty(definition.ResourceName) && String.IsNullOrEmpty(definition.Path)) {
                throw new ArgumentException(AtlasWeb.ScriptResourceDefinition_NameAndPathCannotBeEmpty, "definition");
            }
            EnsureAbsoluteOrAppRelative(definition.Path);
            EnsureAbsoluteOrAppRelative(definition.DebugPath);
            EnsureAbsoluteOrAppRelative(definition.CdnPath);
            EnsureAbsoluteOrAppRelative(definition.CdnDebugPath);
            assembly = NormalizeAssembly(assembly);
            _definitions[new Tuple<String, Assembly>(name, assembly)] = definition;
        }

        public void Clear() {
            _definitions.Clear();
        }

        private void EnsureAbsoluteOrAppRelative(string path) {
            if (!String.IsNullOrEmpty(path) &&
                !UrlPath.IsAppRelativePath(path) && // ~/foo..
                !UrlPath.IsRooted(path) && // /foo
                !Uri.IsWellFormedUriString(path, UriKind.Absolute)) { // http://...
                throw new InvalidOperationException(
                    String.Format(CultureInfo.InvariantCulture, AtlasWeb.ScriptResourceDefinition_InvalidPath, path));
            }
        }

        public ScriptResourceDefinition GetDefinition(string name) {
            return GetDefinition(name, AssemblyCache.SystemWebExtensions);
        }

        public ScriptResourceDefinition GetDefinition(string name, Assembly assembly) {
            if (String.IsNullOrEmpty(name)) {
                throw new ArgumentException(AtlasWeb.Common_NullOrEmpty, "name");
            }
            ScriptResourceDefinition definition;
            assembly = NormalizeAssembly(assembly);
            _definitions.TryGetValue(new Tuple<string, Assembly>(name, assembly), out definition);
            return definition;
        }

        public ScriptResourceDefinition GetDefinition(ScriptReference scriptReference) {
            if (scriptReference == null) {
                throw new ArgumentNullException("scriptReference");
            }
            string name = scriptReference.Name;
            Assembly assembly = null;
            ScriptResourceDefinition definition = null;
            if (!String.IsNullOrEmpty(name)) {
                assembly = scriptReference.GetAssembly();
                definition = ScriptManager.ScriptResourceMapping.GetDefinition(name, assembly);
            }
            return definition;
        }

        public ScriptResourceDefinition RemoveDefinition(string name) {
            return RemoveDefinition(name, AssemblyCache.SystemWebExtensions);
        }

        public ScriptResourceDefinition RemoveDefinition(string name, Assembly assembly) {
            if (String.IsNullOrEmpty(name)) {
                throw new ArgumentException(AtlasWeb.Common_NullOrEmpty, "name");
            }
            ScriptResourceDefinition definition;
            assembly = NormalizeAssembly(assembly);
            _definitions.TryRemove(new Tuple<String, Assembly>(name, assembly), out definition);
            return definition;
        }

        #region IScriptResourceMapping Members
        IScriptResourceDefinition IScriptResourceMapping.GetDefinition(string name) {
            return GetDefinition(name);
        }

        IScriptResourceDefinition IScriptResourceMapping.GetDefinition(string name, Assembly assembly) {
            return GetDefinition(name, assembly);
        }
        #endregion

        private static Assembly NormalizeAssembly(Assembly assembly) {
            if ((assembly != null) && AssemblyCache.IsAjaxFrameworkAssembly(assembly)) {
                assembly = null;
            }
            return assembly;
        }
    }
}