using Recyclarr.Cli.Pipelines.Generic;
using Recyclarr.Cli.Pipelines.QualityProfile.Models;
using Recyclarr.Common.Extensions;
using Recyclarr.Common.FluentValidation;
using Recyclarr.Config.Models;
using Recyclarr.ServarrApi.QualityProfile;

namespace Recyclarr.Cli.Pipelines.QualityProfile.PipelinePhases;

public class QualityProfileTransactionPhase(QualityProfileStatCalculator statCalculator)
    : ITransactionPipelinePhase<QualityProfilePipelineContext>
{
    public void Execute(QualityProfilePipelineContext context, IServiceConfiguration config)
    {
        var transactions = new QualityProfileTransactionData();

        var updatedProfiles = BuildUpdatedProfiles(transactions, context.ConfigOutput, context.ApiFetchOutput);
        UpdateProfileScores(updatedProfiles);

        updatedProfiles = ValidateProfiles(updatedProfiles, transactions.InvalidProfiles);

        AssignProfiles(transactions, updatedProfiles);
        context.TransactionOutput = transactions;
    }

    private void AssignProfiles(
        QualityProfileTransactionData transactions,
        IEnumerable<UpdatedQualityProfile> updatedProfiles)
    {
        var profilesWithStats = updatedProfiles
            .Select(statCalculator.Calculate)
            .ToLookup(x => x.HasChanges);

        transactions.UnchangedProfiles = profilesWithStats[false].ToList();
        transactions.ChangedProfiles = profilesWithStats[true].ToList();
    }

    private static List<UpdatedQualityProfile> ValidateProfiles(
        IEnumerable<UpdatedQualityProfile> transactions,
        ICollection<InvalidProfileData> invalidProfiles)
    {
        var validator = new UpdatedQualityProfileValidator();

        return transactions
            .IsValid(validator, (errors, profile) =>
                invalidProfiles.Add(new InvalidProfileData(profile, errors)))
            .ToList();
    }

    private static List<UpdatedQualityProfile> BuildUpdatedProfiles(
        QualityProfileTransactionData transactions,
        IEnumerable<ProcessedQualityProfileData> guideData,
        QualityProfileServiceData serviceData)
    {
        // Match quality profiles in the user's config to profiles in the service.
        // For each match, we return a tuple including the list of custom format scores ("formatItems").
        // Using GroupJoin() because we want a LEFT OUTER JOIN so we can list which quality profiles in config
        // do not match profiles in Radarr.
        var matchedProfiles = guideData
            .GroupJoin(serviceData.Profiles,
                x => x.Profile.Name,
                x => x.Name,
                (x, y) => (x, y.FirstOrDefault()),
                StringComparer.InvariantCultureIgnoreCase);

        var updatedProfiles = new List<UpdatedQualityProfile>();

        foreach (var (config, dto) in matchedProfiles)
        {
            if (dto is null && !config.ShouldCreate)
            {
                transactions.NonExistentProfiles.Add(config.Profile.Name);
                continue;
            }

            var organizer = new QualityItemOrganizer();
            var newDto = dto ?? serviceData.Schema;

            updatedProfiles.Add(new UpdatedQualityProfile
            {
                ProfileConfig = config,
                ProfileDto = newDto,
                UpdateReason = dto is null ? QualityProfileUpdateReason.New : QualityProfileUpdateReason.Changed,
                UpdatedQualities = organizer.OrganizeItems(newDto, config.Profile)
            });
        }

        return updatedProfiles;
    }

    private static void UpdateProfileScores(IEnumerable<UpdatedQualityProfile> updatedProfiles)
    {
        foreach (var profile in updatedProfiles)
        {
            profile.InvalidExceptCfNames = GetInvalidExceptCfNames(
                profile.ProfileConfig.Profile.ResetUnmatchedScores, profile.ProfileDto);

            profile.UpdatedScores = ProcessScoreUpdates(profile.ProfileConfig, profile.ProfileDto);
        }
    }

    private static IReadOnlyCollection<string> GetInvalidExceptCfNames(
        ResetUnmatchedScoresConfig resetConfig,
        QualityProfileDto profileDto)
    {
        var except = resetConfig.Except;
        if (except.Count == 0)
        {
            return Array.Empty<string>();
        }

        var serviceCfNames = profileDto.FormatItems.Select(x => x.Name).ToList();
        return except
            .Distinct(StringComparer.InvariantCultureIgnoreCase)
            .Where(x => serviceCfNames.TrueForAll(y => !y.EqualsIgnoreCase(x)))
            .ToList();
    }

    private static List<UpdatedFormatScore> ProcessScoreUpdates(
        ProcessedQualityProfileData profileData,
        QualityProfileDto profileDto)
    {
        var scoreMap = profileData.CfScores
            .FullOuterHashJoin(profileDto.FormatItems,
                x => x.FormatId,
                x => x.Format,
                // Exists in config, but not in service (these are unusual and should be errors)
                // See `FormatScoreUpdateReason` for reason why we need this (it's preview mode)
                l => UpdatedFormatScore.New(l),
                // Exists in service, but not in config
                r => UpdatedFormatScore.Reset(r, profileData),
                // Exists in both service and config
                (l, r) => UpdatedFormatScore.Updated(r, l))
            .ToList();

        return scoreMap;
    }
}