aoc2025/day12/input.zig

const std = @import("std");
const shapeModule = @import("shape.zig");
const Shape = shapeModule.Shape;

pub const AreaRequirements = struct {
    rows: i32,
    cols: i32,
    shapesCount: []i32,
};

pub const Input = struct {
    shapes: []Shape,
    areas: []AreaRequirements,
};

fn parseShape(shapeText: []const u8) Shape {
    var it = std.mem.tokenizeScalar(u8, shapeText, '\n');
    _ = it.next(); // skip header
    
    var shape: Shape = .{
        .data = undefined,
    };
    
    for (0..3) |row| {
        const rowText = it.next().?;
        for (0..3) |col| {
            shape.setCell(@intCast(row), @intCast(col), rowText[col]);
        }
    }

    return shape;
}

fn parseAreaRequirements(allocator: std.mem.Allocator, line: []const u8) !AreaRequirements {
    var it = std.mem.tokenizeSequence(u8, line, ": ");
    const sizeText = it.next().?;
    const shapesCountText = it.next().?;

    var sizeTextIt = std.mem.tokenizeScalar(u8, sizeText, 'x');
    const rowsText = sizeTextIt.next().?;
    const colsText = sizeTextIt.next().?;

    const rows = try std.fmt.parseInt(i32, rowsText, 10);
    const cols = try std.fmt.parseInt(i32, colsText, 10);

    var shapesCountTextIt = std.mem.tokenizeScalar(u8, shapesCountText, ' ');
    var shapesCount = std.ArrayList(i32).empty;
    while (shapesCountTextIt.next()) |shapeCountText| {
      const shapeCount = try shapesCount.addOne(allocator);
      shapeCount.* = try std.fmt.parseInt(i32, shapeCountText, 10);
    }
    
    const area: AreaRequirements = .{
        .rows = rows,
        .cols = cols,
        .shapesCount = shapesCount.items,
    };

    return area;
}

pub fn parseInput(allocator: std.mem.Allocator, inputBuffer: []u8) !Input {
    var shapes = std.ArrayList(Shape).empty;
    var areas = std.ArrayList(AreaRequirements).empty;

    var i = std.mem.tokenizeSequence(u8, inputBuffer, "\n\n");
    while (i.next()) |inputBlock| {
        if (inputBlock.len >= 2 and inputBlock[1] == ':') {
            const shape = try shapes.addOne(allocator);
            shape.* = parseShape(inputBlock);
        } else {
            var it = std.mem.tokenizeScalar(u8, inputBlock, '\n');
            while(it.next()) |line| {
                const area = try areas.addOne(allocator);
                area.* = try parseAreaRequirements(allocator, line);
            }
        }
    }

    const input: Input = .{
        .shapes = shapes.items,
        .areas = areas.items,
    };

    return input;
}

pub fn readInputIntoString(allocator: std.mem.Allocator, fileName: []const u8) ![]u8 {
    const inputFile = try std.fs.cwd().openFile(
        fileName, .{.mode = .read_only,});
    defer inputFile.close();

    var inputFileReader = inputFile.reader(
      try allocator.alignedAlloc(u8, null, 1024));
    const inputFileSize = try inputFileReader.getSize();

    const inputBuffer = try allocator.alignedAlloc(u8, null, inputFileSize);
    try inputFileReader.interface.readSliceAll(inputBuffer);
    return inputBuffer;
}