using System.Collections.Generic;
using Pidgin;
using static Pidgin.Parser;
using static Pidgin.Parser<char>;

namespace SourceGenerator {
    internal static class AutoTranslate {
        internal static Parser<char, (string name, Maybe<IEnumerable<ISelectorPart>> selector)> Parser() {
            var sheetName = Any
                .AtLeastOnceUntil(Lookahead(Char('[').IgnoreResult().Or(End)))
                .Select(string.Concat)
                .Labelled("sheetName");

            var numPair = Map(
                    (first, second) => (ISelectorPart) new IndexRange(
                        uint.Parse(string.Concat(first)),
                        uint.Parse(string.Concat(second))
                    ),
                    Digit.AtLeastOnce().Before(Char('-')),
                    Digit.AtLeastOnce()
                )
                .Labelled("numPair");
            var singleRow = Digit
                .AtLeastOnce()
                .Select(string.Concat)
                .Select(num => (ISelectorPart) new SingleRow(uint.Parse(num)));
            var column = String("col-")
                .Then(Digit.AtLeastOnce())
                .Select(string.Concat)
                .Select(num => (ISelectorPart) new ColumnSpecifier(uint.Parse(num)));
            var noun = String("noun")
                .Select(_ => (ISelectorPart) new NounMarker());

            var selectorItems = OneOf(
                    Try(numPair),
                    singleRow,
                    column,
                    noun
                )
                .Separated(Char(','))
                .Labelled("selectorItems");
            var selector = selectorItems
                .Between(Char('['), Char(']'))
                .Labelled("selector");

            return Map(
                (name, selector) => (name, selector),
                sheetName,
                selector.Optional()
            );
        }
    }

    internal interface ISelectorPart {
    }

    internal class SingleRow : ISelectorPart {
        public uint Row { get; }

        public SingleRow(uint row) {
            this.Row = row;
        }
    }

    internal class IndexRange : ISelectorPart {
        public uint Start { get; }
        public uint End { get; }

        public IndexRange(uint start, uint end) {
            this.Start = start;
            this.End = end;
        }
    }

    internal class NounMarker : ISelectorPart {
    }

    internal class ColumnSpecifier : ISelectorPart {
        public uint Column { get; }

        public ColumnSpecifier(uint column) {
            this.Column = column;
        }
    }
}