using System.Xml.Linq;
using LiquidCode.Tester.Common.Models;

namespace LiquidCode.Tester.Worker.Services;

/// <summary>
/// Parser for Polygon problem.xml format
/// </summary>
public class PolygonProblemXmlParser
{
    private readonly ILogger<PolygonProblemXmlParser> _logger;

    public PolygonProblemXmlParser(ILogger<PolygonProblemXmlParser> logger)
    {
        _logger = logger;
    }

    public PolygonProblemDescriptor? ParseProblemXml(string xmlPath)
    {
        try
        {
            var doc = XDocument.Load(xmlPath);
            var problem = doc.Element("problem");

            if (problem == null)
            {
                _logger.LogWarning("Invalid problem.xml: root 'problem' element not found");
                return null;
            }

            var judging = problem.Element("judging");
            if (judging == null)
            {
                _logger.LogWarning("No 'judging' section found in problem.xml");
                return null;
            }

            var testset = judging.Element("testset");
            if (testset == null)
            {
                _logger.LogWarning("No 'testset' section found in problem.xml");
                return null;
            }

            var descriptor = new PolygonProblemDescriptor
            {
                ShortName = problem.Attribute("short-name")?.Value ?? "unknown",
                Revision = int.TryParse(problem.Attribute("revision")?.Value, out var rev) ? rev : 0
            };

            // Parse time limit (in milliseconds)
            var timeLimitText = testset.Element("time-limit")?.Value;
            if (int.TryParse(timeLimitText, out var timeLimit))
            {
                descriptor.TimeLimitMs = timeLimit;
            }

            // Parse memory limit (in bytes)
            var memoryLimitText = testset.Element("memory-limit")?.Value;
            if (long.TryParse(memoryLimitText, out var memoryLimit))
            {
                descriptor.MemoryLimitMb = (int)(memoryLimit / (1024 * 1024)); // Convert bytes to MB
            }

            // Parse test count
            var testCountText = testset.Element("test-count")?.Value;
            if (int.TryParse(testCountText, out var testCount))
            {
                descriptor.TestCount = testCount;
            }

            // Parse path patterns
            descriptor.InputPathPattern = testset.Element("input-path-pattern")?.Value ?? "tests/%02d";
            descriptor.AnswerPathPattern = testset.Element("answer-path-pattern")?.Value ?? "tests/%02d.a";

            // Parse solutions to find main solution
            var assets = problem.Element("assets");
            if (assets != null)
            {
                var solutions = assets.Element("solutions");
                if (solutions != null)
                {
                    // Try to find main solution first
                    var mainSolution = solutions.Elements("solution")
                        .FirstOrDefault(s => s.Attribute("tag")?.Value == "main");

                    // If no main solution, try to find any accepted solution
                    if (mainSolution == null)
                    {
                        mainSolution = solutions.Elements("solution")
                            .FirstOrDefault(s => s.Attribute("tag")?.Value == "accepted");
                    }

                    if (mainSolution != null)
                    {
                        var source = mainSolution.Element("source");
                        if (source != null)
                        {
                            descriptor.MainSolutionPath = source.Attribute("path")?.Value;
                            descriptor.MainSolutionType = source.Attribute("type")?.Value;

                            _logger.LogInformation("Found main solution: {Path} (type: {Type})",
                                descriptor.MainSolutionPath, descriptor.MainSolutionType);
                        }
                    }
                    else
                    {
                        _logger.LogWarning("No main or accepted solution found in problem.xml");
                    }
                }
            }

            _logger.LogInformation(
                "Parsed problem.xml: {ShortName} (rev {Revision}), {TestCount} tests, TL={TimeLimit}ms, ML={MemoryLimit}MB",
                descriptor.ShortName, descriptor.Revision, descriptor.TestCount, descriptor.TimeLimitMs, descriptor.MemoryLimitMb);

            return descriptor;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to parse problem.xml at {Path}", xmlPath);
            return null;
        }
    }
}

/// <summary>
/// Descriptor parsed from problem.xml
/// </summary>
public class PolygonProblemDescriptor
{
    public string ShortName { get; set; } = string.Empty;
    public int Revision { get; set; }
    public int TimeLimitMs { get; set; } = 2000;
    public int MemoryLimitMb { get; set; } = 256;
    public int TestCount { get; set; }
    public string InputPathPattern { get; set; } = "tests/%02d";
    public string AnswerPathPattern { get; set; } = "tests/%02d.a";
    public string? MainSolutionPath { get; set; }
    public string? MainSolutionType { get; set; }
}