/*
 * Copyright 2019 faddenSoft
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
using System;
using System.Collections.Generic;
using System.Diagnostics;

namespace SourceGen {
    /// <summary>
    /// Subclass of Symbol used for symbols defined in the platform or project.
    /// 
    /// Instances are immutable.
    /// </summary>
    public class DefSymbol : Symbol {
        /// <summary>
        /// Data format descriptor.
        /// </summary>
        public FormatDescriptor DataDescriptor { get; private set; }

        /// <summary>
        /// User-supplied comment.
        /// </summary>
        public string Comment { get; private set; }

        public string Tag { get; private set; }

        /// <summary>
        /// Cross-reference data, generated by the analyzer.
        /// </summary>
        public XrefSet Xrefs { get; private set; }

        // NOTE: might be nice to identify the symbol's origin, e.g. which platform
        //       symbol file it was defined in.  This could then be stored in a
        //       DisplayList line, for benefit of the Info panel.

        /// <summary>
        /// Internal base-object constructor, called by other constructors.
        /// </summary>
        private DefSymbol(string label, int value, Source source, Type type)
                : base(label, value, source, type) {
            Debug.Assert(source == Source.Platform || source == Source.Project);
            Debug.Assert(type == Type.ExternalAddr || type == Type.Constant);
            Xrefs = new XrefSet();
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="label">Symbol's label.</param>
        /// <param name="value">Symbol's value.</param>
        /// <param name="source">Symbol source (general point of origin).</param>
        /// <param name="type">Symbol type.</param>
        /// <param name="formatSubType">Format descriptor sub-type, so we know how the
        ///   user wants the value to be displayed.</param>
        /// <param name="comment">End-of-line comment.</param>
        /// <param name="tag">Symbol tag, used for grouping platform symbols.</param>
        public DefSymbol(string label, int value, Source source, Type type,
                FormatDescriptor.SubType formatSubType, string comment, string tag)
                : this(label, value, source, type) {
            Debug.Assert(comment != null);
            Debug.Assert(tag != null);

            // Length doesn't matter; use 1 to get prefab object.
            DataDescriptor = FormatDescriptor.Create(1,
                FormatDescriptor.Type.NumericLE, formatSubType);

            Comment = comment;
            Tag = tag;
        }

        /// <summary>
        /// Constructs a DefSymbol from a Symbol and a format descriptor.  This is used
        /// for project symbols.
        /// </summary>
        /// <param name="sym">Base symbol.</param>
        /// <param name="dfd">Format descriptor.</param>
        /// <param name="comment">End-of-line comment.</param>
        public DefSymbol(Symbol sym, FormatDescriptor dfd, string comment)
                : this(sym.Label, sym.Value, sym.SymbolSource, sym.SymbolType) {
            Debug.Assert(comment != null);

            DataDescriptor = dfd;
            Comment = comment;
            Tag = string.Empty;
        }

        public override string ToString() {
            return base.ToString() + ":" + DataDescriptor + ";" + Comment +
                (string.IsNullOrEmpty(Tag) ? "" : " [" + Tag + "]");
        }
    }
}