using System.Text.Json;
using System.Text.Json.Serialization;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using RealCV.Application.Interfaces;
using RealCV.Application.Models;
using RealCV.Infrastructure.Configuration;
using RealCV.Infrastructure.Data;
using RealCV.Infrastructure.ExternalApis;
using RealCV.Infrastructure.Services;

namespace CVBatchTester;

// DTOs for test JSON format (snake_case with nested personal object)
record TestCVData
{
    public string? CvId { get; init; }
    public string? Category { get; init; }
    public List<string>? ExpectedFlags { get; init; }
    public TestPersonalData? Personal { get; init; }
    public string? Profile { get; init; }
    public List<TestEmploymentEntry>? Employment { get; init; }
    public List<TestEducationEntry>? Education { get; init; }
    public List<string>? Skills { get; init; }
}

record TestPersonalData
{
    public string? Name { get; init; }
    public string? Email { get; init; }
    public string? Phone { get; init; }
    public string? Address { get; init; }
    public string? LinkedIn { get; init; }
}

record TestEmploymentEntry
{
    public string? Company { get; init; }
    public string? JobTitle { get; init; }
    public string? StartDate { get; init; }
    public string? EndDate { get; init; }
    public string? Location { get; init; }
    public string? Description { get; init; }
    public List<string>? Achievements { get; init; }
}

record TestEducationEntry
{
    public string? Institution { get; init; }
    public string? Qualification { get; init; }
    public string? Subject { get; init; }
    public string? Classification { get; init; }
    public string? StartDate { get; init; }
    public string? EndDate { get; init; }
}

class Program
{
    private static StreamWriter? _logWriter;

    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        PropertyNameCaseInsensitive = true,
        PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
        Converters = { new JsonStringEnumConverter() }
    };

    static async Task<int> Main(string[] args)
    {
        var folderPath = args.FirstOrDefault() ?? AskForFolder();

        if (string.IsNullOrEmpty(folderPath) || !Directory.Exists(folderPath))
        {
            Log($"Error: Folder not found: {folderPath}");
            Log("Usage: CVBatchTester <folder-path> [--output <file>]");
            Log("  e.g. CVBatchTester /home/user/cvs");
            Log("  e.g. CVBatchTester /home/user/cvs --output /tmp/results.log");
            return 1;
        }

        // Check for --output flag
        var outputIndex = Array.IndexOf(args, "--output");
        var logPath = outputIndex >= 0 && outputIndex < args.Length - 1
            ? args[outputIndex + 1]
            : Path.Combine(folderPath, $"batch-results-{DateTime.Now:yyyyMMdd-HHmmss}.log");

        _logWriter = new StreamWriter(logPath, false) { AutoFlush = true };

        Log($"CV Batch Verification Tester");
        Log($"Processing CVs from: {folderPath}");
        Log($"Output log: {logPath}");
        Log($"Started: {DateTime.Now:yyyy-MM-dd HH:mm:ss}");
        Log(new string('=', 80));

        // Setup DI
        var services = new ServiceCollection();
        ConfigureServices(services);
        var provider = services.BuildServiceProvider();

        // Find CV files
        var cvFiles = Directory.GetFiles(folderPath, "*.*", SearchOption.TopDirectoryOnly)
            .Where(f => f.EndsWith(".pdf", StringComparison.OrdinalIgnoreCase) ||
                        f.EndsWith(".docx", StringComparison.OrdinalIgnoreCase) ||
                        f.EndsWith(".doc", StringComparison.OrdinalIgnoreCase) ||
                        f.EndsWith(".json", StringComparison.OrdinalIgnoreCase))
            .OrderBy(f => f)
            .ToList();

        Log($"Found {cvFiles.Count} CV files\n");

        if (cvFiles.Count == 0)
        {
            Log("No CV files found (.pdf, .docx, .doc, .json)");
            return 1;
        }

        // Track results
        var allUnverifiedEmployers = new List<string>();
        var allUnverifiedInstitutions = new List<string>();
        var totalEmployers = 0;
        var verifiedEmployers = 0;
        var totalEducation = 0;
        var verifiedEducation = 0;
        var processedCount = 0;
        var errorCount = 0;

        foreach (var cvFile in cvFiles)
        {
            Log($"\n{new string('=', 80)}");
            Log($"[{++processedCount}/{cvFiles.Count}] {Path.GetFileName(cvFile)}");
            Log(new string('=', 80));

            try
            {
                using var scope = provider.CreateScope();
                var parser = scope.ServiceProvider.GetRequiredService<ICVParserService>();
                var companyVerifier = scope.ServiceProvider.GetRequiredService<ICompanyVerifierService>();
                var eduVerifier = scope.ServiceProvider.GetRequiredService<IEducationVerifierService>();

                // Parse CV - handle JSON files differently
                CVData cv;
                if (cvFile.EndsWith(".json", StringComparison.OrdinalIgnoreCase))
                {
                    var jsonContent = await File.ReadAllTextAsync(cvFile);
                    var testCv = JsonSerializer.Deserialize<TestCVData>(jsonContent, JsonOptions)
                        ?? throw new InvalidOperationException("Failed to deserialize JSON CV");

                    // Convert TestCVData to CVData
                    cv = ConvertTestCVData(testCv);
                    Log($"Loaded JSON CV: {cv.FullName}");
                }
                else
                {
                    await using var stream = File.OpenRead(cvFile);
                    cv = await parser.ParseAsync(stream, Path.GetFileName(cvFile));
                    Log($"Parsed CV: {cv.FullName}");
                }

                // Verify Employers
                if (cv.Employment?.Count > 0)
                {
                    Log($"\nEMPLOYERS ({cv.Employment.Count}):");
                    Log(new string('-', 60));

                    foreach (var emp in cv.Employment)
                    {
                        totalEmployers++;
                        try
                        {
                            var result = await companyVerifier.VerifyCompanyAsync(
                                emp.CompanyName,
                                emp.StartDate,
                                emp.EndDate,
                                emp.JobTitle);

                            var icon = result.IsVerified ? "✓" : "✗";
                            var period = FormatPeriod(emp.StartDate, emp.EndDate);

                            Log($"\n  {icon} {emp.CompanyName}");
                            Log($"    Period: {period}");
                            Log($"    Role: {emp.JobTitle}");

                            if (result.IsVerified)
                            {
                                verifiedEmployers++;
                                Log($"    Match: {result.MatchedCompanyName} ({result.MatchScore}%)");
                                if (!string.IsNullOrEmpty(result.MatchedCompanyNumber))
                                    Log($"    Company #: {result.MatchedCompanyNumber}");
                                if (!string.IsNullOrEmpty(result.CompanyStatus))
                                    Log($"    Status: {result.CompanyStatus}");
                            }
                            else
                            {
                                allUnverifiedEmployers.Add(emp.CompanyName);
                            }

                            if (!string.IsNullOrEmpty(result.VerificationNotes))
                                Log($"    Note: {result.VerificationNotes}");

                            // Display any flags (warnings/issues)
                            if (result.Flags?.Count > 0)
                            {
                                foreach (var flag in result.Flags)
                                {
                                    var flagIcon = flag.Severity == "Critical" ? "⚠️" : "ℹ️";
                                    Log($"    {flagIcon} FLAG [{flag.Type}]: {flag.Message}");
                                }
                            }
                        }
                        catch (Exception ex)
                        {
                            Log($"\n  ✗ {emp.CompanyName}");
                            Log($"    ERROR: {ex.Message}");
                            allUnverifiedEmployers.Add(emp.CompanyName);
                        }
                    }
                }

                // Verify Education
                if (cv.Education?.Count > 0)
                {
                    Log($"\nEDUCATION ({cv.Education.Count}):");
                    Log(new string('-', 60));

                    var eduEntries = cv.Education.Select(e => new EducationEntry
                    {
                        Institution = e.Institution,
                        Qualification = e.Qualification,
                        Subject = e.Subject,
                        StartDate = e.StartDate,
                        EndDate = e.EndDate
                    }).ToList();

                    var eduResults = eduVerifier.VerifyAll(eduEntries);

                    foreach (var result in eduResults)
                    {
                        totalEducation++;
                        var icon = result.IsVerified ? "✓" : "✗";

                        Log($"\n  {icon} {result.ClaimedInstitution}");
                        Log($"    Qualification: {result.ClaimedQualification}");
                        if (!string.IsNullOrEmpty(result.ClaimedSubject))
                            Log($"    Subject: {result.ClaimedSubject}");

                        if (result.IsVerified)
                        {
                            verifiedEducation++;
                            if (result.MatchedInstitution != null &&
                                !result.MatchedInstitution.Equals(result.ClaimedInstitution, StringComparison.OrdinalIgnoreCase))
                            {
                                Log($"    Match: {result.MatchedInstitution}");
                            }
                        }
                        else
                        {
                            allUnverifiedInstitutions.Add(result.ClaimedInstitution ?? "Unknown");
                            Log($"    Status: {result.Status}");
                        }

                        if (!string.IsNullOrEmpty(result.VerificationNotes))
                            Log($"    Note: {result.VerificationNotes}");
                    }
                }
            }
            catch (Exception ex)
            {
                errorCount++;
                Log($"ERROR processing file: {ex.Message}");
            }
        }

        // Print Summary
        Log($"\n\n{new string('=', 80)}");
        Log("VERIFICATION SUMMARY");
        Log(new string('=', 80));

        Log($"\nCVs Processed: {processedCount - errorCount}/{cvFiles.Count}");
        if (errorCount > 0)
            Log($"Errors: {errorCount}");

        var empRate = totalEmployers > 0 ? verifiedEmployers * 100 / totalEmployers : 0;
        var eduRate = totalEducation > 0 ? verifiedEducation * 100 / totalEducation : 0;

        Log($"\nEmployers: {verifiedEmployers}/{totalEmployers} verified ({empRate}%)");
        Log($"Education: {verifiedEducation}/{totalEducation} verified ({eduRate}%)");

        // List unverified employers
        var uniqueUnverifiedEmployers = allUnverifiedEmployers
            .GroupBy(e => e, StringComparer.OrdinalIgnoreCase)
            .OrderByDescending(g => g.Count())
            .ThenBy(g => g.Key)
            .ToList();

        if (uniqueUnverifiedEmployers.Count > 0)
        {
            Log($"\n{new string('-', 60)}");
            Log($"UNVERIFIED EMPLOYERS ({uniqueUnverifiedEmployers.Count} unique):");
            foreach (var group in uniqueUnverifiedEmployers)
            {
                var count = group.Count() > 1 ? $" (x{group.Count()})" : "";
                Log($"  - {group.Key}{count}");
            }
        }

        // List unverified institutions
        var uniqueUnverifiedInstitutions = allUnverifiedInstitutions
            .GroupBy(i => i, StringComparer.OrdinalIgnoreCase)
            .OrderByDescending(g => g.Count())
            .ThenBy(g => g.Key)
            .ToList();

        if (uniqueUnverifiedInstitutions.Count > 0)
        {
            Log($"\n{new string('-', 60)}");
            Log($"UNVERIFIED INSTITUTIONS ({uniqueUnverifiedInstitutions.Count} unique):");
            foreach (var group in uniqueUnverifiedInstitutions)
            {
                var count = group.Count() > 1 ? $" (x{group.Count()})" : "";
                Log($"  - {group.Key}{count}");
            }
        }

        Log($"\nCompleted: {DateTime.Now:yyyy-MM-dd HH:mm:ss}");
        Log($"\n{new string('=', 80)}");

        _logWriter?.Close();
        Console.WriteLine($"\nResults written to: {logPath}");

        return 0;
    }

    static void Log(string message)
    {
        Console.WriteLine(message);
        _logWriter?.WriteLine(message);
    }

    static string AskForFolder()
    {
        Console.Write("Enter CV folder path: ");
        return Console.ReadLine() ?? "";
    }

    static string FormatPeriod(DateOnly? start, DateOnly? end)
    {
        var startStr = start?.ToString("MMM yyyy") ?? "?";
        var endStr = end?.ToString("MMM yyyy") ?? "Present";
        return $"{startStr} - {endStr}";
    }

    static CVData ConvertTestCVData(TestCVData testCv)
    {
        return new CVData
        {
            FullName = testCv.Personal?.Name ?? "Unknown",
            Email = testCv.Personal?.Email,
            Phone = testCv.Personal?.Phone,
            Employment = testCv.Employment?.Select(e => new EmploymentEntry
            {
                CompanyName = e.Company ?? "Unknown",
                JobTitle = e.JobTitle ?? "Unknown",
                Location = e.Location,
                StartDate = ParseDate(e.StartDate),
                EndDate = ParseDate(e.EndDate),
                IsCurrent = e.EndDate == null,
                Description = e.Description
            }).ToList() ?? [],
            Education = testCv.Education?.Select(e => new EducationEntry
            {
                Institution = e.Institution ?? "Unknown",
                Qualification = e.Qualification,
                Subject = e.Subject,
                StartDate = ParseDate(e.StartDate),
                EndDate = ParseDate(e.EndDate)
            }).ToList() ?? [],
            Skills = testCv.Skills ?? []
        };
    }

    static DateOnly? ParseDate(string? dateStr)
    {
        if (string.IsNullOrEmpty(dateStr)) return null;

        // Try parsing YYYY-MM format
        if (dateStr.Length == 7 && dateStr[4] == '-')
        {
            if (int.TryParse(dateStr[..4], out var year) && int.TryParse(dateStr[5..], out var month))
            {
                return new DateOnly(year, month, 1);
            }
        }

        // Try standard parsing
        if (DateOnly.TryParse(dateStr, out var date))
        {
            return date;
        }

        return null;
    }

    static void ConfigureServices(IServiceCollection services)
    {
        // Load configuration - try multiple locations
        var configPaths = new[]
        {
            "/var/www/realcv",
            "/git/RealCV/src/RealCV.Web",
            Path.GetFullPath(Path.Combine(AppContext.BaseDirectory, "..", "..", "..", "..", "..", "src", "RealCV.Web"))
        };

        var webProjectPath = configPaths.FirstOrDefault(Directory.Exists) ?? "/git/RealCV/src/RealCV.Web";
        Log($"Loading config from: {webProjectPath}");

        var configuration = new ConfigurationBuilder()
            .SetBasePath(webProjectPath)
            .AddJsonFile("appsettings.json", optional: true)
            .AddJsonFile("appsettings.Development.json", optional: true)
            .AddJsonFile("appsettings.Production.json", optional: true)
            .Build();

        // Logging - show info level for verification details
        services.AddLogging(builder =>
        {
            builder.AddConsole();
            builder.SetMinimumLevel(LogLevel.Information);
            // Filter out noisy libraries
            builder.AddFilter("Microsoft", LogLevel.Warning);
            builder.AddFilter("System", LogLevel.Warning);
        });

        // Database
        var connectionString = configuration.GetConnectionString("DefaultConnection")
            ?? "Server=127.0.0.1;Database=RealCV;User Id=SA;Password=TrueCV_Sql2024!;TrustServerCertificate=True";

        services.AddDbContextFactory<ApplicationDbContext>(options =>
            options.UseSqlServer(connectionString));

        // Companies House - use configuration binding
        services.Configure<CompaniesHouseSettings>(configuration.GetSection(CompaniesHouseSettings.SectionName));
        services.AddHttpClient<CompaniesHouseClient>();

        // Anthropic - use configuration binding
        services.Configure<AnthropicSettings>(configuration.GetSection(AnthropicSettings.SectionName));
        services.AddScoped<ICompanyNameMatcherService, AICompanyNameMatcherService>();

        // Services
        services.AddScoped<ICompanyVerifierService, CompanyVerifierService>();
        services.AddScoped<IEducationVerifierService, EducationVerifierService>();
        services.AddScoped<ICVParserService, CVParserService>();
    }
}