/* Formatter.cs
 * part of zaaReloaded2
 * 
 * Copyright 2015-2017 Daniel Kraus
 * 
 * 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.Linq;
using System.Text;
using System.Diagnostics;
using Microsoft.Office.Interop.Word;
using zaaReloaded2.LabModel;
using zaaReloaded2.Controller;
using zaaReloaded2.Controller.Elements;

namespace zaaReloaded2.Formatter
{
    /// <summary>
    /// Formats and writes a <see cref="Laboratory"/> to a Word document.
    /// </summary>
    public class Formatter
    {
        #region Properties

        /// <summary>
        /// Gets or sets the Settings that this Formatter works with.
        /// </summary>
        public Settings Settings { get; set; }

        /// <summary>
        /// Gets or sets the <see cref="Laboratory"/> that shall be
        /// formatted.
        /// </summary>
        public Laboratory Laboratory
        {
            [DebuggerStepThrough]
            get
            {
                return _laboratory;
            }
            set
            {
                _laboratory = value;
                _timePointFormatters = new TimePointFormatterDictionary();
                foreach (TimePoint tp in _laboratory.TimePoints.Values)
                {
                    _timePointFormatters[tp.TimeStamp] =
                        new TimePointFormatter(tp, Settings.ReferenceStyle, Settings.AbnormalStyle);
                }
            }
        }

        /// <summary>
        /// Gets the current working set of TimePointFormatters.
        /// </summary>
        public Dictionary<DateTime, TimePointFormatter> WorkingTimePoints { get; private set; }

        /// <summary>
        /// Is true if this Formatter object carries a Laboratory with
        /// at least one time point, and if there are Settings to work with.
        /// </summary>
        public bool CanRun
        {
            get
            {
                return (Settings != null)
                    && (Laboratory != null)
                    && (Laboratory.TimePoints.Count > 0);
            }
        }

        #endregion

        #region Constructors

        public Formatter()
        {
            Settings = new Settings();
            _secondaryBuffer = new DocumentWriter();
            _primaryBuffer = new DocumentWriter(_secondaryBuffer);
        }

        public Formatter(Document document)
            : this()
        {
            Document = document;
            _secondaryBuffer.Document = document;
        }

        #endregion

        #region Public methods

        /// <summary>
        /// Writes some text to the current document.
        /// Does nothing if there is no current document.
        /// </summary>
        /// <param name="text">Text to write to the current document.
        /// </param>
        public void Write(string text)
        {
            _primaryBuffer.Write(text);
        }

        /// <summary>
        /// Writes a paragraph to the document.
        /// </summary>
        /// <param name="text"></param>
        public void WriteParagraph(string text)
        {
            _primaryBuffer.WriteLine(text);
        }

        /// <summary>
        /// Formats the laboratory and writes it to a Word document.
        /// </summary>
        /// <param name="document">Word document to write to (at the
        /// current position of the cursor).</param>
        public void Run()
        {
            if (!CanRun)
            {
                if (Settings == null)
                    throw new InvalidOperationException("No settings data to work with.");
                if ((Laboratory == null) || Laboratory.TimePoints.Count == 0)
                    throw new NoLaboratoryDataException("No laboratory data to format.");
                throw new InvalidOperationException("Cannot run formatter.");
            }

            // Create undo record and styles prior to iterating over the elements
            // because a column switching element might trigger output to the
            // document.
            Helpers.StartUndo("Laborformatierung");
            CreateStyles();

            int current = 0;
            while (current < Settings.Elements.Count)
            {
                // If there are FormatElements in the first level of the
                // elements list, collect all consecutive ones and process
                // them for each individual time point.
                if (Settings.Elements[current] is FormatElementBase)
                {
                    int notAFormatElement = CollectFormatElements(current);
                    IList<FormatElementBase> list = Settings.Elements
                            .Skip(current)
                            .Take(notAFormatElement - current)
                            .Cast<FormatElementBase>().ToList();
                    ProcessAllTimePoints(list);
                    current = notAFormatElement;
                }
                else
                {
                    // The current element is not derived from FormatElementBase;
                    // so go ahead and 'run' it.
                    Settings.Elements[current].Run(this);
                    current++;
                }
            }

            _secondaryBuffer.Flush();
            Helpers.EndUndo();
        }

        /// <summary>
        /// Selects one time point per day in the laboratory.
        /// </summary>
        public void ProcessEachDay(ControlElementBase controlElement)
        {
            IEnumerable<DateTime> days = _timePointFormatters.Keys.Select(k => k.Date).Distinct();
            foreach (DateTime day in days)
            {
                ProcessDay(
                    controlElement,
                    _timePointFormatters
                        .Where(kv => kv.Key.Date == day.Date)
                        .ToDictionary(kv => kv.Key, kv => kv.Value)
                    );
            }
        }

        /// <summary>
        /// Selects all time points for the first day in the
        /// laboratory.
        /// </summary>
        public void ProcessFirstDay(ControlElementBase controlElement)
        {
            DateTime first = _timePointFormatters.First().Key;
            ProcessDay(
                controlElement,
                _timePointFormatters
                    .Where(kv => kv.Key.Date == first.Date)
                    .ToDictionary(kv => kv.Key, kv => kv.Value)
                );
        }

        /// <summary>
        /// Selects all time points for the first day in the
        /// laboratory.
        /// </summary>
        public void ProcessLastDay(ControlElementBase controlElement)
        {
            DateTime last = _timePointFormatters.Last().Key;
            ProcessDay(
                controlElement,
                _timePointFormatters
                    .Where(kv => kv.Key.Date == last.Date)
                    .ToDictionary(kv => kv.Key, kv => kv.Value)
                );
        }

        /// <summary>
        /// Processes the FormatElementBase children of <paramref name="controlElement"/>
        /// for each individual time point.
        /// </summary>
        /// <param name="controlElement">ControlElementBase descendant whose
        /// FormatElementBase children to process.</param>
        public void ProcessAllTimePoints(ControlElementBase controlElement)
        {
            ProcessAllTimePoints(controlElement.Children);
        }

        /// <summary>
        /// Inserts a table with two columns into the document.
        /// </summary>
        public void InsertTwoColumns()
        {
            _secondaryBuffer.Flush();
            if (Document != null)
            {
                Range r = Document.ActiveWindow.Selection.Range;
                _table = Document.Tables.Add(r, NumRows: 1, NumColumns: 2);
                _table.AllowAutoFit = true;
                _table.AutoFitBehavior(WdAutoFitBehavior.wdAutoFitWindow);
                _table.PreferredWidthType = WdPreferredWidthType.wdPreferredWidthPercent;
                _table.PreferredWidth = 100;
                _table.Borders.Enable = 0;
            }
        }

        /// <summary>
        /// Moves the insertion point to the next column in a layout
        /// table.
        /// </summary>
        public void NextColumn()
        {
            if (_table == null)
            {
                throw new InvalidOperationException(
                    "Kann nicht zur nächsten Spalte wechseln, da bislang keine Tabelle eingefügt wurde.");
            }
            _secondaryBuffer.Flush();
            Document.ActiveWindow.Selection.MoveRight(WdUnits.wdCell);
        }

        /// <summary>
        /// Creates a paragraph and character styles in the document.
        /// </summary>
        public void CreateStyles()
        {
            if (Document != null)
            {
                Logger.Info("CreateStyles");
                Style style;
                // Don't see a better way to check for the existence of a particular
                // paragraph style than by using a try...catch construction.
                try
                {
                    style = Document.Styles[Properties.Settings.Default.StyleParagraph];
                    Logger.Info("CreateStyles: Found paragraph style in document");
                }
                catch
                {
                    Logger.Info("CreateStyles: Need to create paragraph style");
                    // Add default paragraph style for laboratory
                    style = Document.Styles.Add(Properties.Settings.Default.StyleParagraph);
                    style.Font.Size = 10; // pt
                    style.Font.Bold = 0;
                    style.Font.Italic = 0;
                    style.Font.Underline = 0;
                    style.ParagraphFormat.SpaceAfter = 0;
                    style.ParagraphFormat.SpaceBefore = 0;
                    style.ParagraphFormat.LeftIndent = 36; // pt
                    style.ParagraphFormat.FirstLineIndent = -36; // pt
                    style.ParagraphFormat.Alignment = WdParagraphAlignment.wdAlignParagraphJustify;
                }
                Bovender.ComHelpers.ReleaseComObject(style);

                try
                {
                    style = Document.Styles[Properties.Settings.Default.StyleHeader];
                    Logger.Info("CreateStyles: Found header style in document");
                }
                catch
                {
                    Logger.Info("CreateStyles: Need to create header style");
                    // Add header paragraph style for laboratory
                    style = Document.Styles.Add(Properties.Settings.Default.StyleHeader);
                    style.Font.Size = 10; // pt
                    style.Font.Bold = 1;
                    style.Font.Italic = 0;
                    style.Font.Underline = WdUnderline.wdUnderlineSingle;
                    style.ParagraphFormat.SpaceAfter = 0;
                    style.ParagraphFormat.SpaceBefore = 12;
                    style.ParagraphFormat.LeftIndent = 36; // pt
                    style.ParagraphFormat.FirstLineIndent = -36; // pt
                    style.ParagraphFormat.Alignment = WdParagraphAlignment.wdAlignParagraphJustify;
                    style.set_NextParagraphStyle(Document.Styles[Properties.Settings.Default.StyleParagraph]);
                }
                Bovender.ComHelpers.ReleaseComObject(style);

                /*
                try
                {
                    style = Document.Styles[Properties.Settings.Default.StyleAbnormal];
                }
                catch
                {
                    // Add character style for abnormal parameters
                    style = Document.Styles.Add(
                        Properties.Settings.Default.StyleAbnormal,
                        WdStyleType.wdStyleTypeCharacter);
                    style.Font.Bold = 1;
                }
                */
            }
        }

        #endregion

        #region Protected methods

        /// <summary>
        /// Collects all consecutive FormatElements from Settings.Elements.
        /// </summary>
        /// <returns>Index of the first element that is not a FormatElement.
        /// </returns>
        protected int CollectFormatElements(int startIndex)
        {
            int i = startIndex;
            while (i < Settings.Elements.Count)
            {
                if (!(Settings.Elements[i] is FormatElementBase))
                {
                    break;
                }
                i++;
            }
            return i;
        }

        protected void ProcessElements(IList<FormatElementBase> formatElements)
        {
            if (formatElements != null)
            {
                foreach (ElementBase element in formatElements)
                {
                    element.Run(this);
                }
            }
        }

        protected void ProcessAllTimePoints(IList<FormatElementBase> formatElements)
        {
            for (int i = 0; i < _timePointFormatters.Count; i++)    
            {
                WorkingTimePoints = _timePointFormatters
                    .Skip(i)
                    .Take(1)
                    .ToDictionary(kv => kv.Key, kv => kv.Value);
                ProcessElements(formatElements);
                if (_primaryBuffer.HasBufferedText)
                {
                    _primaryBuffer.Prepend(
                        WorkingTimePoints.First().Value.GetDateAndTimeHeader()
                        );
                }
                _primaryBuffer.Flush();
            }
        }

        protected void ProcessDay(
            ControlElementBase controlElement,
            Dictionary<DateTime, TimePointFormatter> workingTimePoints)
        {
            if (workingTimePoints == null)
                throw new ArgumentNullException("workingTimePoints");

            WorkingTimePoints = workingTimePoints;
            ProcessElements(controlElement.Children);
            if (_primaryBuffer.HasBufferedText)
            {
                _primaryBuffer.Prepend(
                    WorkingTimePoints.First().Value.GetDateHeader());
            }
            _primaryBuffer.Flush();

        }

        #endregion

        #region Protected properties

        /// <summary>
        /// Gets the working Word document.
        /// </summary>
        protected Document Document { get; set; }

        #endregion

        #region Fields

        TimePointFormatterDictionary _timePointFormatters;
        Laboratory _laboratory;
        DocumentWriter _primaryBuffer;
        DocumentWriter _secondaryBuffer;
        Table _table;

        #endregion

        #region Class logger

        private static NLog.Logger Logger { get { return _logger.Value; } }

        private static readonly Lazy<NLog.Logger> _logger = new Lazy<NLog.Logger>(() => NLog.LogManager.GetCurrentClassLogger());

        #endregion
    }
}