// /*
//  * Copyright 2009 ZXing authors
//  *
//  * 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 ZXing.Common;

namespace ZXing.PDF417.Internal
{
    /// <summary>
    /// Represents a Column in the Detection Result
    /// </summary>
    /// <author>Guenther Grau (Java Core)</author>
    /// <author>Stephen Furlani (C# Port)</author>
    public sealed class DetectionResultRowIndicatorColumn : DetectionResultColumn
    {
        /// <summary>
        /// Gets or sets a value indicating whether this instance is the left indicator
        /// </summary>
        /// <value><c>true</c> if this instance is left; otherwise, <c>false</c>.</value>
        public bool IsLeft { get; set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="ZXing.PDF417.Internal.DetectionResultRowIndicatorColumn"/> class.
        /// </summary>
        /// <param name="box">Box.</param>
        /// <param name="isLeft">If set to <c>true</c> is left.</param>
        public DetectionResultRowIndicatorColumn(BoundingBox box, bool isLeft) : base (box)
        {
            this.IsLeft = isLeft;
            this.Codewords = new Codeword[box.MaxY - box.MinY + 1];
        }

        /// <summary>
        /// Sets the Row Numbers as Inidicator Columns
        /// </summary>
        public void SetRowNumbers()
        {
            foreach (var cw in Codewords)
            {
                if (cw != null)
                {
                    cw.SetRowNumberAsRowIndicatorColumn();
                }
            }
            // (from item in items where item != null do item.SomeMethod())
        }


        /// <summary>
        /// TODO implement properly
        /// TODO maybe we should add missing codewords to store the correct row number to make
        /// finding row numbers for other columns easier
        /// use row height count to make detection of invalid row numbers more reliable
        /// </summary>
        /// <returns>The indicator column row numbers.</returns>
        /// <param name="metadata">Metadata.</param>
        public int AdjustCompleteIndicatorColumnRowNumbers(BarcodeMetadata metadata)
        {
            SetRowNumbers(); // Assign this as an indicator column
            RemoveIncorrectCodewords(metadata);

            ResultPoint top = IsLeft ? Box.TopLeft : Box.TopRight;
            ResultPoint bottom = IsLeft ? Box.BottomLeft : Box.BottomRight;

            int firstRow = IndexForRow((int)top.Y);
            int lastRow = IndexForRow((int)bottom.Y);

            // We need to be careful using the average row height.  
            // Barcode could be skewed so that we have smaller and taller rows
            float averageRowHeight = (lastRow - firstRow) / (float)metadata.RowCount;

            // initialize loop
            int barcodeRow = -1;
            int maxRowHeight = 1;
            int currentRowHeight = 0;

            for (int codewordRow = firstRow; codewordRow < lastRow; codewordRow++)
            {
                var codeword = Codewords[codewordRow];
                if (codeword == null)
                {
                    continue;
                }

                //      float expectedRowNumber = (codewordsRow - firstRow) / averageRowHeight;
                //      if (Math.abs(codeword.getRowNumber() - expectedRowNumber) > 2) {
                //        SimpleLog.log(LEVEL.WARNING,
                //            "Removing codeword, rowNumberSkew too high, codeword[" + codewordsRow + "]: Expected Row: " +
                //                expectedRowNumber + ", RealRow: " + codeword.getRowNumber() + ", value: " + codeword.getValue());
                //        codewords[codewordsRow] = null;
                //      }

                int rowDifference = codeword.RowNumber - barcodeRow;

                // TODO improve handling with case where first row indicator doesn't start with 0

                if (rowDifference == 0)
                {
                    currentRowHeight ++;
                } else if (rowDifference == 1)
                {
                    maxRowHeight = Math.Max(maxRowHeight, currentRowHeight);
                    currentRowHeight = 1;
                    barcodeRow = codeword.RowNumber;
                } else if (rowDifference < 0)
                {
                    Codewords[codewordRow] = null;
                } else if (codeword.RowNumber >= metadata.RowCount)
                {
                    Codewords[codewordRow] = null;
                } else if (rowDifference > codewordRow)
                {
                    Codewords[codewordRow] = null;
                } else
                {
                    int checkedRows;
                    if (maxRowHeight > 2)
                    {
                        checkedRows = (maxRowHeight - 2) * rowDifference;
                    } else
                    {
                        checkedRows = rowDifference;
                    }
                    bool closePreviousCodewordFound = checkedRows > codewordRow;
                    for (int i = 1; i <= checkedRows && !closePreviousCodewordFound; i++)
                    {
                        closePreviousCodewordFound = Codewords[codewordRow - i] != null;
                    }
                    if (closePreviousCodewordFound)
                    {
                        Codewords[codewordRow] = null;
                    } else
                    {
                        barcodeRow = codeword.RowNumber;
                        currentRowHeight = 1;
                    }
                }

            }
            return (int)(averageRowHeight + 0.5);
        }

        /// <summary>
        /// Adjusts the in omplete indicator column row numbers.
        /// </summary>
        /// <param name="metadata">Metadata.</param>
        public int AdjustIncompleteIndicatorColumnRowNumbers(BarcodeMetadata metadata)
        {
            ResultPoint top = IsLeft ? Box.TopLeft : Box.TopRight;
            ResultPoint bottom = IsLeft ? Box.BottomLeft : Box.BottomRight;
            
            int firstRow = IndexForRow((int)top.Y);
            int lastRow = IndexForRow((int)bottom.Y);
            
            // We need to be careful using the average row height.  
            // Barcode could be skewed so that we have smaller and taller rows
            float averageRowHeight = (lastRow - firstRow) / (float)metadata.RowCount;

            // initialize loop
            int barcodeRow = -1;
            int maxRowHeight = 1;
            int currentRowHeight = 0;
            
            for (int codewordRow = firstRow; codewordRow < lastRow; codewordRow++)
            {
                var codeword = Codewords[codewordRow];
                if (codeword == null)
                {
                    continue;
                }

                codeword.SetRowNumberAsRowIndicatorColumn();

                int rowDifference = codeword.RowNumber - barcodeRow;

                // TODO improve handling with case where first row indicator doesn't start with 0

                if (rowDifference == 0)
                {
                    currentRowHeight++;
                } else if (rowDifference == 1)
                {
                    maxRowHeight = Math.Max(maxRowHeight, currentRowHeight);
                    currentRowHeight = 1;
                    barcodeRow = codeword.RowNumber;
                } else if (codeword.RowNumber > metadata.RowCount)
                {
                    Codewords[codewordRow] = null;
                } else
                {
                    barcodeRow = codeword.RowNumber;
                    currentRowHeight = 1;
                }

            }
            return (int)(averageRowHeight + 0.5);
        }

        /// <summary>
        /// Gets the row heights.
        /// </summary>
        /// <returns>The row heights.</returns>
        public int[] GetRowHeights()
        {
            BarcodeMetadata metadata = GetBarcodeMetadata();
            if (metadata == null)
            {
                return null;
            }
            AdjustIncompleteIndicatorColumnRowNumbers(metadata);
            int[] result = Enumerable.Repeat(0, metadata.RowCount).ToArray();
            foreach (var word in Codewords)
            {
                if (word != null)
                {
                    result[word.RowNumber]++;
                }
            }
            return result;
        }

        /// <summary>
        /// Gets the barcode metadata.
        /// </summary>
        /// <returns>The barcode metadata.</returns>
        public BarcodeMetadata GetBarcodeMetadata()
        {
            BarcodeValue barcodeColumnCount = new BarcodeValue();
            BarcodeValue barcodeRowCountUpperPart = new BarcodeValue();
            BarcodeValue barcodeRowCountLowerPart = new BarcodeValue();
            BarcodeValue barcodeECLevel = new BarcodeValue();
            foreach (Codeword codeword in Codewords)
            {
                if (codeword == null)
                {
                    continue;
                }
                codeword.SetRowNumberAsRowIndicatorColumn();
                int rowIndicatorValue = codeword.Value % 30;
                int codewordRowNumber = codeword.RowNumber;
                if (!IsLeft)
                {
                    codewordRowNumber += 2;
                }
                switch (codewordRowNumber % 3)
                {
                    case 0:
                        barcodeRowCountUpperPart.SetValue(rowIndicatorValue * 3 + 1);
                        break;
                    case 1:
                        barcodeECLevel.SetValue(rowIndicatorValue / 3);
                        barcodeRowCountLowerPart.SetValue(rowIndicatorValue % 3);
                        break;
                    case 2:
                        barcodeColumnCount.SetValue(rowIndicatorValue + 1);
                        break;
                }
            }
            // Maybe we should check if we have ambiguous values?
            if ((barcodeColumnCount.GetValue().Length == 0) ||
                (barcodeRowCountUpperPart.GetValue().Length == 0) ||
                (barcodeRowCountLowerPart.GetValue().Length == 0) ||
                (barcodeECLevel.GetValue().Length == 0) ||
                barcodeColumnCount.GetValue()[0] < 1 ||
                barcodeRowCountUpperPart.GetValue()[0] + barcodeRowCountLowerPart.GetValue()[0] < PDF417Common.MIN_ROWS_IN_BARCODE ||
                barcodeRowCountUpperPart.GetValue()[0] + barcodeRowCountLowerPart.GetValue()[0] > PDF417Common.MAX_ROWS_IN_BARCODE)
            {
                return null;
            }
            BarcodeMetadata barcodeMetadata = new BarcodeMetadata(barcodeColumnCount.GetValue()[0],
                                                                  barcodeRowCountUpperPart.GetValue()[0], 
                                                                  barcodeRowCountLowerPart.GetValue()[0], 
                                                                  barcodeECLevel.GetValue()[0]);
            RemoveIncorrectCodewords(barcodeMetadata);
            return barcodeMetadata;
        }

        /// <summary>
        /// Prune the codewords which do not match the metadata
        /// TODO Maybe we should keep the incorrect codewords for the start and end positions?
        /// </summary>
        /// <param name="codewords">Codewords.</param>
        /// <param name="metadata">Metadata.</param>
        private void RemoveIncorrectCodewords(BarcodeMetadata metadata)
        {
            for (int row = 0; row < Codewords.Length; row++)
            {
                var codeword = Codewords[row];
                if (codeword == null)
                    continue;

                int indicatorValue = codeword.Value % 30;
                int rowNumber = codeword.RowNumber;

                // Row does not exist in the metadata
                if (rowNumber > metadata.RowCount)
                {
                    Codewords[row] = null; // remove this.
                    continue;
                }

                if (!IsLeft)
                {
                    rowNumber += 2;
                }

                switch (rowNumber % 3)
                {
                    default:
                    case 0:
                        if (indicatorValue * 3 + 1 != metadata.RowCountUpper)
                        {
                            Codewords[row] = null;
                        }
                        break;

                    case 1:
                        if (indicatorValue % 3 != metadata.RowCountLower ||
                            indicatorValue / 3 != metadata.ErrorCorrectionLevel)
                        {
                            Codewords[row] = null;
                        }
                        break;

                    case 2:
                        if (indicatorValue + 1 != metadata.ColumnCount)
                        {
                            Codewords[row] = null;
                        }
                        break;
                }

            }
        }

        /// <summary>
        /// Returns a <see cref="System.String"/> that represents the current <see cref="ZXing.PDF417.Internal.DetectionResultRowIndicatorColumn"/>.
        /// </summary>
        /// <returns>A <see cref="System.String"/> that represents the current <see cref="ZXing.PDF417.Internal.DetectionResultRowIndicatorColumn"/>.</returns>
        public override string ToString()
        {
            return "Is Left: " + IsLeft + " \n" + base.ToString();
        }

    }
}