package com.sundata.internalevaluation.model.antlr;

import org.antlr.v4.runtime.ANTLRInputStream;
import org.antlr.v4.runtime.CharStream;
import org.antlr.v4.runtime.CharStreams;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.tree.ParseTree;
import org.antlr.v4.runtime.tree.ParseTreeWalker;

import java.util.HashMap;
import java.util.Map;

public class IntervalEvaluator {
    private final Map<Interval, Integer> intervals = new HashMap<>();

    public static void main(String[] args) {
        String input = """
                	-> [0,10) -> 10
                	-> (10,20) -> 20
                	-> [20,30] -> 30
                	-> (30,+] -> 40
                	-> [-,+] -> 100
                	-> [] -> 0
                """;

        CharStream stream = CharStreams.fromString(input);

        // 1. 词法分析
        IntervalParserLexer lexer = new IntervalParserLexer(stream);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        IntervalParserParser parser = new IntervalParserParser(tokens);

        IntervalEvaluator evaluator = new IntervalEvaluator();
        evaluator.parseAndEvaluate(parser.parse());

        // 测试不同的输入值
        System.out.println(evaluator.evaluate(15));  // 输出 20
        System.out.println(evaluator.evaluate(25));  // 输出 30
        System.out.println(evaluator.evaluate(5));   // 输出 10
        System.out.println(evaluator.evaluate(null));// 输出 0
    }

    public void parseAndEvaluate(ParseTree tree) {
        ParseTreeWalker.DEFAULT.walk(new IntervalListener(this), tree);
    }

    public int evaluate(Number x) {
        if (x == null) {
            return intervals.get(new Interval(true, null, null));
        }

        for (Map.Entry<Interval, Integer> entry : intervals.entrySet()) {
            Interval interval = entry.getKey();
            if (interval.contains(x.doubleValue())) {
                return entry.getValue();
            }
        }

        return intervals.get(new Interval(false, null, null));
    }

    private static class Interval {
        private final boolean empty;
        private final Double lower;
        private final Double upper;
        private final boolean lowerInclusive;
        private final boolean upperInclusive;

        public Interval(boolean empty, Double lower, Double upper) {
            this.empty = empty;
            this.lower = lower;
            this.upper = upper;
            this.lowerInclusive = false;
            this.upperInclusive = false;
        }

        public Interval(boolean lowerInclusive, Double lower, boolean upperInclusive, Double upper) {
            this.empty = false;
            this.lower = lower;
            this.upper = upper;
            this.lowerInclusive = lowerInclusive;
            this.upperInclusive = upperInclusive;
        }

        public boolean contains(double value) {
            if (empty) {
                return false;
            }

            boolean lowerValid = lower == null || (lowerInclusive ? value >= lower : value > lower);
            boolean upperValid = upper == null || (upperInclusive ? value <= upper : value < upper);

            return lowerValid && upperValid;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;

            Interval interval = (Interval) o;

            if (empty != interval.empty) return false;
            if (lower != null ? !lower.equals(interval.lower) : interval.lower != null) return false;
            if (upper != null ? !upper.equals(interval.upper) : interval.upper != null) return false;
            if (lowerInclusive != interval.lowerInclusive) return false;
            return upperInclusive == interval.upperInclusive;
        }

        @Override
        public int hashCode() {
            int result = (empty ? 1 : 0);
            result = 31 * result + (lower != null ? lower.hashCode() : 0);
            result = 31 * result + (upper != null ? upper.hashCode() : 0);
            result = 31 * result + (lowerInclusive ? 1 : 0);
            result = 31 * result + (upperInclusive ? 1 : 0);
            return result;
        }
    }

    private static class IntervalListener extends IntervalParserBaseListener {
        private final IntervalEvaluator evaluator;

        public IntervalListener(IntervalEvaluator evaluator) {
            this.evaluator = evaluator;
        }

        @Override
        public void enterLine(IntervalParserParser.LineContext ctx) {
            IntervalParserParser.IntervalContext intervalCtx = ctx.interval();
            Interval interval = parseInterval(intervalCtx);
            int value = Integer.parseInt(ctx.value().NUMBER().getText());
            evaluator.intervals.put(interval, value);
        }

        private Interval parseInterval(IntervalParserParser.IntervalContext ctx) {
            if (ctx.getChild(0).getText().equals("[")) {
                if (ctx.getChildCount() == 2) {
                    return new Interval(true, null, null);
                }

                boolean lowerInclusive = ctx.getChild(0).getText().equals("[");
                boolean upperInclusive = ctx.getChild(ctx.getChildCount() - 1).getText().equals("]");
                Double lower = ctx.lower != null ? Double.parseDouble(ctx.lower.getText()) : null;
                Double upper = ctx.upper != null ? Double.parseDouble(ctx.upper.getText()) : null;

                if (ctx.getChild(1).getText().equals("-")) {
                    return new Interval(false, null, null);
                }

                return new Interval(lowerInclusive, lower, upperInclusive, upper);
            } else {
                boolean lowerInclusive = ctx.getChild(0).getText().equals("(");
                boolean upperInclusive = ctx.getChild(ctx.getChildCount() - 1).getText().equals("]");
                Double lower = ctx.lower != null ? Double.parseDouble(ctx.lower.getText()) : null;
                Double upper = ctx.upper != null ? Double.parseDouble(ctx.upper.getText()) : null;

                if (upper != null && upper.toString().equals("+")) {
                    upper = null;
                }

                return new Interval(lowerInclusive, lower, upperInclusive, upper);
            }
        }
    }
}