package aoc2025

import println
import readInput
import splitInts
import java.util.*
import kotlin.math.abs

/*
--- Day 9: Movie Theater ---
https://adventofcode.com/2025/day/9
*/
fun main() {

    val inlineTestInput = """
7,3
7,1
11,1
11,7
9,7
9,5
2,5
2,3
"""

    fun part1(input: List<String>): Long {
        val coords = input.map { it.splitInts(",") }
        var maxArea = 0L
        for (i1 in 0 until coords.size step 2) {
            for (i2 in i1 + 2 until coords.size step 2) {
                maxArea = ((abs(coords[i1][0] - coords[i2][0]) + 1).toLong() * (abs(coords[i1][1] - coords[i2][1]) + 1).toLong()).coerceAtLeast(maxArea)
            }
        }
        return maxArea
    }

    fun findRanges(set: TreeMap<Int, ArrayList<IntRange>>, x1: Int, y1: Int, x2: Int, y2: Int): Boolean {
        var it = set.ceilingEntry(y1)
        while (it != null && it.key <= y2) {
            val xRanges = it.value.filter { it.first() >= x1 && it.last() <= x2 }
            if (it.key != y1 && it.key != y2 && xRanges.size > 0) return false
            if ((it.key == y1 || it.key == y2) && xRanges.size > 1) return false
            // Java TreeMap is crap -- I would like to iterate from first entry to last
            it = set.ceilingEntry(it.key + 1)
        }
        return true
    }

    fun intersects(coords: List<List<Int>>, x1: Int, y1: Int, x2: Int, y2: Int): Boolean {
        for (z1 in 0 until coords.size) {
            val z2 = if (z1 != coords.size - 1) z1 + 1 else 0
            if (coords[z1][0] == coords[z2][0]) {
                // vertical
                val miny = coords[z1][1].coerceAtMost(coords[z2][1])
                val maxy = coords[z1][1].coerceAtLeast(coords[z2][1])
                if (coords[z1][0] > x1 && coords[z1][0] < x2 &&
                    (miny.coerceAtLeast(y1) < maxy.coerceAtMost(y2))
                )
                    return true
            } else {
                // horizontal
                val minx = coords[z1][0].coerceAtMost(coords[z2][0])
                val maxx = coords[z1][0].coerceAtLeast(coords[z2][0])
                if (coords[z1][1] > y1 && coords[z1][1] < y2 &&
                    (minx.coerceAtLeast(x1) < maxx.coerceAtMost(x2))
                )
                    return true
            }
        }
        return false
    }

    fun part2(input: List<String>): Long {
        val coords = input.map { it.splitInts(",") }
        val xSpans = TreeMap<Int, ArrayList<IntRange>>()
        val ySpans = TreeMap<Int, ArrayList<IntRange>>()
        for (i1 in 0 until coords.size) {
            val i2 = if (i1 != coords.size - 1) i1 + 1 else 0
            if (i1 and 1 == 1) {
                xSpans.getOrPut(coords[i1][1]) { ArrayList<IntRange>() }.add(
                    IntRange(
                        coords[i1][0].coerceAtMost(coords[i2][0]),
                        coords[i1][0].coerceAtLeast(coords[i2][0])
                    )
                )
            } else {
                ySpans.getOrPut(coords[i1][0]) { ArrayList<IntRange>() }.add(
                    IntRange(
                        coords[i1][1].coerceAtMost(coords[i2][1]),
                        coords[i1][1].coerceAtLeast(coords[i2][1])
                    )
                )
            }
        }

        //xSpans.values.forEach { it.sortBy { it.first } }
        //ySpans.values.forEach { it.sortBy { it.first } }

        var maxArea = 0L
        for (i1 in 0 until coords.size step 1) {
            for (i2 in i1 + 1 until coords.size step 1) {
                val x1 = coords[i1][0].coerceAtMost(coords[i2][0])
                val x2 = coords[i1][0].coerceAtLeast(coords[i2][0])
                val y1 = coords[i1][1].coerceAtMost(coords[i2][1])
                val y2 = coords[i1][1].coerceAtLeast(coords[i2][1])
                if (x1 == x2 || y1 == y2) continue

                val area = ((x2 - x1 + 1).toLong() * (y2 - y1 + 1).toLong())
                if (area > maxArea) {
//                    if (!findRanges(xSpans, x1, y1, x2, y2) ||
//                        !findRanges(ySpans, y1, x1, y2, x2)
//                    ) continue
                    if (!intersects(coords, x1, y1, x2, y2))
                        maxArea = area
                }
            }
        }
        return maxArea
    }

    // test if implementation meets criteria from the description, like:
    val testInput = inlineTestInput.trim().reader().readLines()
    //val testInput = readInput("aoc2025/Day09_test")
    val testInputPart1Result = part1(testInput)
    println("Part 1 Test: $testInputPart1Result")
    val testInputPart2Result = part2(testInput)
    println("Part 2 Test: $testInputPart2Result")
    check(testInputPart1Result == 50L)
    check(testInputPart2Result == 24L)
    val input = readInput("aoc2025/Day09")
    part1(input).println()
    part2(input).println()
}