using System.Collections.Generic;
using Glass.Typesetting;
using UnitTestSharp;

namespace Glass.UnitTests.Typesetting
{
    public class MeasuredWordsTests : TestFixture
    {
        public static MeasuredWord WordEndingAt(int end) =>
            new MeasuredWord(new LineBreak(end, isMandatory: false), contentWidth: end * 10, leadingKerning: 0,
                endKerning: 0);

        /// <summary>
        /// Words ending at each of `ends`, in an array with a spare slot past them, which must never be read.
        /// </summary>
        public static MeasuredWords Holding(params int[] ends)
        {
            var words = new MeasuredWord[ends.Length + 1];
            for (int i = 0; i < ends.Length; ++i)
            {
                words[i] = WordEndingAt(ends[i]);
            }

            words[ends.Length] = WordEndingAt(99);
            return new MeasuredWords(WordMeasurerTests.TestFont(), "", words, ends.Length);
        }

        public static List<string> ReadAll(MeasuredWords words)
        {
            var returnMe = new List<string>();
            while (words.MoveNext())
            {
                returnMe.Add(WordMeasurerTests.Describe(words.CurrentStart, words.Current, words.Ends));
            }

            return returnMe;
        }

        public class CtorTests : TestFixture
        {
            public void KeepsTheFontTextAndCount()
            {
                SpriteFontDefinition font = WordMeasurerTests.TestFont();
                var words = new MeasuredWords(font, "ab cd", new MeasuredWord[4], count: 2);

                CheckEqual(font, words.Font);
                CheckEqual("ab cd", words.Text.ToString());
                CheckEqual(2, words.Count);
            }
        }

        public class EndsTests : TestFixture
        {
            public void MeasureWithTheFontsSpace()
            {
                var word = new MeasuredWord(new LineBreak(3, isMandatory: false, trailingSpaces: 1), contentWidth: 20,
                    leadingKerning: 0, endKerning: 0);

                CheckEqual(WordMeasurerTests.SpaceWidth, Holding().Ends.TrailingWidthOf(word));
            }
        }

        public class MoveNextTests : TestFixture
        {
            public void ReadsTheCountedWordsInOrder_AndNoFurther()
            {
                CheckEqual(new[]
                    {
                        "0..2..2 lead 0 content 20 trailing 0 hyphen 0",
                        "2..5..5 lead 0 content 50 trailing 0 hyphen 0",
                    },
                    ReadAll(Holding(2, 5)));
            }

            public void NoWords_ReadsNothing()
            {
                CheckFalse(Holding().MoveNext());
            }

            public void PastTheEnd_StaysFalse()
            {
                MeasuredWords words = Holding(2);
                ReadAll(words);

                CheckFalse(words.MoveNext());
            }
        }

        public class RewindTests : TestFixture
        {
            public void ReadsTheWordsAgain()
            {
                MeasuredWords words = Holding(2, 5);
                List<string> firstRead = ReadAll(words);
                words.Rewind();

                CheckEqual(firstRead, ReadAll(words));
            }
        }

        public class CurrentIndexTests : TestFixture
        {
            public void CountsWordsFromZero()
            {
                MeasuredWords words = Holding(2, 5);
                words.MoveNext();
                words.MoveNext();

                CheckEqual(1, words.CurrentIndex);
            }
        }
    }
}