using System;

namespace AvalonStudio.TextEditor.Document
{
#if !NREFACTORY

    /// <summary>
    ///     A document representing a source code file for refactoring.
    ///     Line and column counting starts at 1.
    ///     Offset counting starts at 0.
    /// </summary>
    public interface IDocument : ITextSource, IServiceProvider
    {
#if NREFACTORY
	/// <summary>
	/// Creates an immutable snapshot of this document.
	/// </summary>
		IDocument CreateDocumentSnapshot();
#endif

        /// <summary>
        ///     Gets/Sets the text of the whole document..
        /// </summary>
        new string Text { get; set; } // hides ITextSource.Text to add the setter

        /// <summary>
        ///     This event is called directly before a change is applied to the document.
        /// </summary>
        /// <remarks>
        ///     It is invalid to modify the document within this event handler.
        ///     Aborting the change (by throwing an exception) is likely to cause corruption of data structures
        ///     that listen to the Changing and Changed events.
        /// </remarks>
        event EventHandler<TextChangeEventArgs> TextChanging;

        /// <summary>
        ///     This event is called directly after a change is applied to the document.
        /// </summary>
        /// <remarks>
        ///     It is invalid to modify the document within this event handler.
        ///     Aborting the event handler (by throwing an exception) is likely to cause corruption of data structures
        ///     that listen to the Changing and Changed events.
        /// </remarks>
        event EventHandler<TextChangeEventArgs> TextChanged;

        /// <summary>
        ///     This event is called after a group of changes is completed.
        /// </summary>
        /// <seealso cref="EndUndoableAction" />
        event EventHandler ChangeCompleted;

        /// <summary>
        ///     Gets the number of lines in the document.
        /// </summary>
        int LineCount { get; }

        /// <summary>
        ///     Gets the document line with the specified number.
        /// </summary>
        /// <param name="lineNumber">The number of the line to retrieve. The first line has number 1.</param>
        IDocumentLine GetLineByNumber(int lineNumber);

        /// <summary>
        ///     Gets the document line that contains the specified offset.
        /// </summary>
        IDocumentLine GetLineByOffset(int offset);

        /// <summary>
        ///     Gets the offset from a text location.
        /// </summary>
        /// <seealso cref="GetLocation" />
        int GetOffset(int line, int column);

        /// <summary>
        ///     Gets the offset from a text location.
        /// </summary>
        /// <seealso cref="GetLocation" />
        int GetOffset(TextLocation location);

        /// <summary>
        ///     Gets the location from an offset.
        /// </summary>
        /// <seealso cref="GetOffset(TextLocation)" />
        TextLocation GetLocation(int offset);

        /// <summary>
        ///     Inserts text.
        /// </summary>
        /// <param name="offset">The offset at which the text is inserted.</param>
        /// <param name="text">The new text.</param>
        /// <remarks>
        ///     Anchors positioned exactly at the insertion offset will move according to their movement type.
        ///     For AnchorMovementType.Default, they will move behind the inserted text.
        ///     The caret will also move behind the inserted text.
        /// </remarks>
        void Insert(int offset, string text);

        /// <summary>
        ///     Inserts text.
        /// </summary>
        /// <param name="offset">The offset at which the text is inserted.</param>
        /// <param name="text">The new text.</param>
        /// <remarks>
        ///     Anchors positioned exactly at the insertion offset will move according to their movement type.
        ///     For AnchorMovementType.Default, they will move behind the inserted text.
        ///     The caret will also move behind the inserted text.
        /// </remarks>
        void Insert(int offset, ITextSource text);

        /// <summary>
        ///     Inserts text.
        /// </summary>
        /// <param name="offset">The offset at which the text is inserted.</param>
        /// <param name="text">The new text.</param>
        /// <param name="defaultAnchorMovementType">
        ///     Anchors positioned exactly at the insertion offset will move according to the anchor's movement type.
        ///     For AnchorMovementType.Default, they will move according to the movement type specified by this parameter.
        ///     The caret will also move according to the <paramref name="defaultAnchorMovementType" /> parameter.
        /// </param>
        void Insert(int offset, string text, AnchorMovementType defaultAnchorMovementType);

        /// <summary>
        ///     Inserts text.
        /// </summary>
        /// <param name="offset">The offset at which the text is inserted.</param>
        /// <param name="text">The new text.</param>
        /// <param name="defaultAnchorMovementType">
        ///     Anchors positioned exactly at the insertion offset will move according to the anchor's movement type.
        ///     For AnchorMovementType.Default, they will move according to the movement type specified by this parameter.
        ///     The caret will also move according to the <paramref name="defaultAnchorMovementType" /> parameter.
        /// </param>
        void Insert(int offset, ITextSource text, AnchorMovementType defaultAnchorMovementType);

        /// <summary>
        ///     Removes text.
        /// </summary>
        /// <param name="offset">Starting offset of the text to be removed.</param>
        /// <param name="length">Length of the text to be removed.</param>
        void Remove(int offset, int length);

        /// <summary>
        ///     Replaces text.
        /// </summary>
        /// <param name="offset">The starting offset of the text to be replaced.</param>
        /// <param name="length">The length of the text to be replaced.</param>
        /// <param name="newText">The new text.</param>
        void Replace(int offset, int length, string newText);

        /// <summary>
        ///     Replaces text.
        /// </summary>
        /// <param name="offset">The starting offset of the text to be replaced.</param>
        /// <param name="length">The length of the text to be replaced.</param>
        /// <param name="newText">The new text.</param>
        void Replace(int offset, int length, ITextSource newText);

        /// <summary>
        ///     Make the document combine the following actions into a single
        ///     action for undo purposes.
        /// </summary>
        void StartUndoableAction();

        /// <summary>
        ///     Ends the undoable action started with <see cref="StartUndoableAction" />.
        /// </summary>
        void EndUndoableAction();

        /// <summary>
        ///     Creates an undo group. Dispose the returned value to close the undo group.
        /// </summary>
        /// <returns>An object that closes the undo group when Dispose() is called.</returns>
        IDisposable OpenUndoGroup();

        /// <summary>
        ///     Creates a new <see cref="ITextAnchor" /> at the specified offset.
        /// </summary>
        /// <inheritdoc cref="ITextAnchor" select="remarks|example" />
        ITextAnchor CreateAnchor(int offset);

        /// <summary>
        ///     Gets the name of the file the document is stored in.
        ///     Could also be a non-existent dummy file name or null if no name has been set.
        /// </summary>
        string FileName { get; }

        /// <summary>
        ///     Fired when the file name of the document changes.
        /// </summary>
        event EventHandler FileNameChanged;
    }

    /// <summary>
    ///     A line inside a <see cref="IDocument" />.
    /// </summary>
    public interface IDocumentLine : ISegment
    {
        /// <summary>
        ///     Gets the length of this line, including the line delimiter.
        /// </summary>
        int TotalLength { get; }

        /// <summary>
        ///     Gets the length of the line terminator.
        ///     Returns 1 or 2; or 0 at the end of the document.
        /// </summary>
        int DelimiterLength { get; }

        /// <summary>
        ///     Gets the number of this line.
        ///     The first line has the number 1.
        /// </summary>
        int LineNumber { get; }

        /// <summary>
        ///     Gets the previous line. Returns null if this is the first line in the document.
        /// </summary>
        IDocumentLine PreviousLine { get; }

        /// <summary>
        ///     Gets the next line. Returns null if this is the last line in the document.
        /// </summary>
        IDocumentLine NextLine { get; }

        /// <summary>
        ///     Gets whether the line was deleted.
        /// </summary>
        bool IsDeleted { get; }
    }

    /// <summary>
    ///     Describes a change of the document text.
    ///     This class is thread-safe.
    /// </summary>

    public class TextChangeEventArgs : EventArgs
    {
        /// <summary>
        ///     Creates a new TextChangeEventArgs object.
        /// </summary>
        public TextChangeEventArgs(int offset, string removedText, string insertedText)
        {
            if (offset < 0)
                throw new ArgumentOutOfRangeException("offset", offset, "offset must not be negative");
            Offset = offset;
            RemovedText = removedText != null ? new StringTextSource(removedText) : StringTextSource.Empty;
            InsertedText = insertedText != null ? new StringTextSource(insertedText) : StringTextSource.Empty;
        }

        /// <summary>
        ///     Creates a new TextChangeEventArgs object.
        /// </summary>
        public TextChangeEventArgs(int offset, ITextSource removedText, ITextSource insertedText)
        {
            if (offset < 0)
                throw new ArgumentOutOfRangeException("offset", offset, "offset must not be negative");
            Offset = offset;
            RemovedText = removedText ?? StringTextSource.Empty;
            InsertedText = insertedText ?? StringTextSource.Empty;
        }

        /// <summary>
        ///     The offset at which the change occurs.
        /// </summary>
        public int Offset { get; }

        /// <summary>
        ///     The text that was removed.
        /// </summary>
        public ITextSource RemovedText { get; }

        /// <summary>
        ///     The number of characters removed.
        /// </summary>
        public int RemovalLength
        {
            get { return RemovedText.TextLength; }
        }

        /// <summary>
        ///     The text that was inserted.
        /// </summary>
        public ITextSource InsertedText { get; }

        /// <summary>
        ///     The number of characters inserted.
        /// </summary>
        public int InsertionLength
        {
            get { return InsertedText.TextLength; }
        }

        /// <summary>
        ///     Gets the new offset where the specified offset moves after this document change.
        /// </summary>
        public virtual int GetNewOffset(int offset, AnchorMovementType movementType = AnchorMovementType.Default)
        {
            if (offset >= Offset && offset <= Offset + RemovalLength)
            {
                if (movementType == AnchorMovementType.BeforeInsertion)
                    return Offset;
                return Offset + InsertionLength;
            }
            if (offset > Offset)
            {
                return offset + InsertionLength - RemovalLength;
            }
            return offset;
        }

        /// <summary>
        ///     Creates TextChangeEventArgs for the reverse change.
        /// </summary>
        public virtual TextChangeEventArgs Invert()
        {
            return new TextChangeEventArgs(Offset, InsertedText, RemovedText);
        }
    }

#endif
}