using System.Text.Json;
using Backend.Domain;
using Microsoft.EntityFrameworkCore;

namespace Backend.Data;

public static partial class SeedDataBootstrapper
{
    private static async Task EnsureSeedOperationalDataAsync(AwardsDbContext db, Season season)
    {
        var categories = await db.Categories
            .Where(item => item.SeasonId == season.Id)
            .ToDictionaryAsync(item => item.Slug, StringComparer.OrdinalIgnoreCase);
        var candidates = await db.Candidates
            .Where(item => item.SeasonId == season.Id)
            .ToArrayAsync();

        var normalizedLegacyState = await NormalizeLegacyDemoLabelsAsync(db);
        await EnsureSeedReviewNominationsAsync(db, season, categories, candidates);

        if (!await db.ClipSubmissions.AnyAsync(item => item.SeasonId == season.Id))
        {
            db.ClipSubmissions.AddRange(
                new ClipSubmission
                {
                    SeasonId = season.Id,
                    CategoryId = ResolveCategoryId(categories, "vtuber-des-jahres-shining-star"),
                    CandidateId = ResolveCandidateId(categories, candidates, "vtuber-des-jahres-shining-star", "Hoshimi Miyu"),
                    SubmittedByTwitchId = "local_user_3",
                    ClipUrl = "https://clips.twitch.tv/StarlitDebutMoment",
                    Title = "Starlight Debut Moment",
                    Creator = "Hoshimi Miyu",
                    Platform = "Twitch",
                    Status = "approved",
                    ReviewNote = "Geprüfter Clip für Voting-Vorschau.",
                    ReviewedByTwitchId = "jayuhime_admin",
                    CreatedFromIp = "127.0.0.1",
                    CreatedAt = new DateTimeOffset(2026, 6, 18, 8, 15, 0, TimeSpan.Zero),
                    ReviewedAt = new DateTimeOffset(2026, 6, 18, 12, 5, 0, TimeSpan.Zero),
                },
                new ClipSubmission
                {
                    SeasonId = season.Id,
                    CategoryId = ResolveCategoryId(categories, "vtuber-des-jahres-shining-star"),
                    CandidateId = ResolveCandidateId(categories, candidates, "vtuber-des-jahres-shining-star", "Kurainu"),
                    SubmittedByTwitchId = "local_user_4",
                    ClipUrl = "https://clips.twitch.tv/KurainuFinaleHype",
                    Title = "Finale-Hype mit Chat-Chaos",
                    Creator = "Kurainu",
                    Platform = "Twitch",
                    Status = "approved",
                    ReviewNote = "Geprüfter Clip für Voting-Vorschau.",
                    ReviewedByTwitchId = "jayuhime_admin",
                    CreatedFromIp = "127.0.0.1",
                    CreatedAt = new DateTimeOffset(2026, 6, 18, 8, 35, 0, TimeSpan.Zero),
                    ReviewedAt = new DateTimeOffset(2026, 6, 18, 12, 10, 0, TimeSpan.Zero),
                },
                new ClipSubmission
                {
                    SeasonId = season.Id,
                    CategoryId = ResolveCategoryId(categories, "best-gaming-shining-star"),
                    CandidateId = ResolveCandidateId(categories, candidates, "best-gaming-shining-star", "Kurainu"),
                    SubmittedByTwitchId = "local_user",
                    ClipUrl = "https://clips.twitch.tv/EpicGamingMoment",
                    Title = "Epischer Clutch im Finale",
                    Creator = "Kurainu",
                    Platform = "Twitch",
                    Status = "pending",
                    CreatedFromIp = "127.0.0.1",
                    CreatedAt = new DateTimeOffset(2026, 6, 17, 9, 10, 0, TimeSpan.Zero),
                },
                new ClipSubmission
                {
                    SeasonId = season.Id,
                    CategoryId = ResolveCategoryId(categories, "gesang-musik-shining-star"),
                    CandidateId = ResolveCandidateId(categories, candidates, "gesang-musik-shining-star", "Melo Diva"),
                    SubmittedByTwitchId = "local_user_2",
                    ClipUrl = "https://www.youtube.com/watch?v=liveCoverMoment",
                    Title = "Live-Cover mit Gänsehaut",
                    Creator = "Melo Diva",
                    Platform = "YouTube",
                    Status = "approved",
                    ReviewNote = "Geprüfter Clip für Review-Workflow.",
                    ReviewedByTwitchId = "jayuhime_admin",
                    CreatedFromIp = "127.0.0.1",
                    CreatedAt = new DateTimeOffset(2026, 6, 18, 10, 30, 0, TimeSpan.Zero),
                    ReviewedAt = new DateTimeOffset(2026, 6, 18, 12, 0, 0, TimeSpan.Zero),
                });
        }

        if (!normalizedLegacyState.HasRiskSeed && !await db.RiskFlags.AnyAsync(item => item.Source == "seed"))
        {
            db.RiskFlags.Add(new RiskFlag
            {
                SeasonId = season.Id,
                TwitchUserId = "sample_user",
                Source = "seed",
                Type = "rapid_vote_updates",
                Severity = "medium",
                Status = "open",
                Summary = "Mehrere Voting-Aenderungen in kurzer Zeit erkannt.",
                CreatedFromIp = "127.0.0.1",
                UserAgent = "seed-bootstrap",
                MetadataJson = JsonSerializer.Serialize(new { recentVoteSubmissions = 3 }),
                CreatedAt = new DateTimeOffset(2026, 6, 17, 8, 40, 0, TimeSpan.Zero),
            });
        }

        if (!normalizedLegacyState.HasAuditSeed && !await db.AdminAuditEntries.AnyAsync(item => item.ActionType == "seed.initialize"))
        {
            db.AdminAuditEntries.Add(new AdminAuditEntry
            {
                AdminTwitchUserId = "system",
                ActionType = "seed.initialize",
                EntityType = "database",
                EntityId = season.Year.ToString(),
                Summary = "Startinhalte wurden in der Datenbank bereitgestellt.",
                MetadataJson = JsonSerializer.Serialize(new { awardCategories = SeedCatalog.AwardCategorySeeds.Length, subcategories = SeedCatalog.DefaultSubcategoryTemplates.Length }),
                CreatedFromIp = "seed",
                UserAgent = "seed-bootstrap",
                CreatedAt = new DateTimeOffset(2026, 6, 17, 8, 32, 0, TimeSpan.Zero),
            });
        }
    }

    private static int? ResolveCategoryId(IReadOnlyDictionary<string, Category> categories, string slug) =>
        categories.TryGetValue(slug, out var category) ? category.Id : null;

    private static int? ResolveCandidateId(
        IReadOnlyDictionary<string, Category> categories,
        IEnumerable<Candidate> candidates,
        string categorySlug,
        string displayName)
    {
        var categoryId = ResolveCategoryId(categories, categorySlug);
        return categoryId is int resolvedCategoryId
            ? candidates.FirstOrDefault(item =>
                item.CategoryId == resolvedCategoryId
                && string.Equals(item.DisplayName, displayName, StringComparison.OrdinalIgnoreCase))?.Id
            : null;
    }

    private static async Task<LegacySeedState> NormalizeLegacyDemoLabelsAsync(AwardsDbContext db)
    {
        var legacySessions = await db.UserSessions
            .Where(item => item.TwitchUserId == "admin_demo" || item.TwitchUserId == "jayuhime_demo" || item.TwitchUserId == "demo_user")
            .ToArrayAsync();

        foreach (var session in legacySessions)
        {
            session.TwitchUserId = session.TwitchUserId switch
            {
                "admin_demo" => "jayuhime_admin",
                "jayuhime_demo" => "jayuhime_viewer",
                "demo_user" => "local_user",
                _ => session.TwitchUserId,
            };
            session.DisplayName = session.DisplayName switch
            {
                "Admin Demo" => "Jayuhime Admin",
                "Demo User" => "Local User",
                _ => session.DisplayName,
            };
        }

        var legacyClipSubmissions = await db.ClipSubmissions
            .Where(item =>
                item.SubmittedByTwitchId == "demo_user" ||
                item.SubmittedByTwitchId == "demo_user_2" ||
                item.ClipUrl.Contains("Demo") ||
                item.ClipUrl.Contains("demo") ||
                (item.ReviewNote != null && item.ReviewNote.Contains("Demo-Clip")))
            .ToArrayAsync();

        foreach (var clip in legacyClipSubmissions)
        {
            clip.SubmittedByTwitchId = clip.SubmittedByTwitchId switch
            {
                "demo_user" => "local_user",
                "demo_user_2" => "local_user_2",
                _ => clip.SubmittedByTwitchId,
            };
            clip.ClipUrl = clip.ClipUrl
                .Replace("DemoGamingMoment", "EpicGamingMoment")
                .Replace("demoSong", "liveCoverMoment");
            clip.ReviewNote = clip.ReviewNote?.Replace("Demo-Clip", "Geprüfter Clip");
        }
        await LinkExistingClipsToCandidatesAsync(db);

        var legacyRiskFlags = await db.RiskFlags
            .Where(item =>
                item.Source == "demo" ||
                item.Summary.StartsWith("Demo:") ||
                item.TwitchUserId == "jayuhime_demo" ||
                item.TwitchUserId == "demo_user")
            .ToArrayAsync();

        foreach (var flag in legacyRiskFlags)
        {
            flag.Source = "seed";
            flag.TwitchUserId = flag.TwitchUserId switch
            {
                "demo_user" => "local_user",
                "jayuhime_demo" => "jayuhime_viewer",
                _ => flag.TwitchUserId,
            };
            flag.Summary = flag.Summary.Replace("Demo: ", string.Empty);
            flag.UserAgent = flag.UserAgent == "demo-seed" ? "seed-bootstrap" : flag.UserAgent;
        }

        var legacyAuditEntries = await db.AdminAuditEntries
            .Where(item =>
                item.ActionType == "demo.seed" ||
                item.Summary.Contains("Demo-Inhalte") ||
                item.AdminTwitchUserId == "admin_demo" ||
                item.AdminTwitchUserId == "jayuhime_demo")
            .ToArrayAsync();

        foreach (var entry in legacyAuditEntries)
        {
            entry.AdminTwitchUserId = entry.AdminTwitchUserId switch
            {
                "admin_demo" => "jayuhime_admin",
                "jayuhime_demo" => "jayuhime_viewer",
                _ => entry.AdminTwitchUserId,
            };
            if (entry.ActionType == "demo.seed")
            {
                entry.ActionType = "seed.initialize";
            }
            if (entry.Summary.Contains("Demo-Inhalte"))
            {
                entry.Summary = "Startinhalte wurden in der Datenbank bereitgestellt.";
            }
        }

        return new LegacySeedState(
            legacyRiskFlags.Length > 0 || await db.RiskFlags.AnyAsync(item => item.Source == "seed"),
            legacyAuditEntries.Length > 0 || await db.AdminAuditEntries.AnyAsync(item => item.ActionType == "seed.initialize"));
    }

    private static async Task LinkExistingClipsToCandidatesAsync(AwardsDbContext db)
    {
        var clips = await db.ClipSubmissions
            .Where(item => item.CandidateId == null && item.CategoryId != null && item.Creator != string.Empty)
            .ToArrayAsync();
        if (clips.Length == 0)
        {
            return;
        }

        var seasonIds = clips.Select(item => item.SeasonId).Distinct().ToArray();
        var categoryIds = clips.Select(item => item.CategoryId!.Value).Distinct().ToArray();
        var candidates = await db.Candidates
            .Where(item => seasonIds.Contains(item.SeasonId) && categoryIds.Contains(item.CategoryId))
            .ToArrayAsync();

        foreach (var clip in clips)
        {
            var creatorKey = NormalizeSeedCandidateKey(clip.Creator);
            var candidate = candidates.FirstOrDefault(item =>
                item.SeasonId == clip.SeasonId
                && item.CategoryId == clip.CategoryId
                && (NormalizeSeedCandidateKey(item.DisplayName) == creatorKey
                    || NormalizeSeedCandidateKey(item.ChannelSlug) == creatorKey));

            if (candidate is not null)
            {
                clip.CandidateId = candidate.Id;
            }
        }
    }

    private static string NormalizeSeedCandidateKey(string value) =>
        new(
            value
                .Trim()
                .TrimStart('@')
                .ToLowerInvariant()
                .Where(char.IsLetterOrDigit)
                .ToArray());

    private static async Task EnsureSeedReviewNominationsAsync(
        AwardsDbContext db,
        Season season,
        IReadOnlyDictionary<string, Category> categories,
        Candidate[] candidates)
    {
        var staleSeedNominations = await db.Nominations
            .Where(item =>
                item.SeasonId == season.Id
                && (
                    item.SubmittedByTwitchId.StartsWith("seed_review_")
                    || item.SubmittedByTwitchId == "twitch_hoshi"
                    || item.SubmittedByTwitchId == "twitch_kurainu"
                    || item.SubmittedByTwitchId.StartsWith("demo_user")
                    || item.SubmittedByTwitchId.StartsWith("local_user")
                ))
            .ToArrayAsync();

        if (staleSeedNominations.Length > 0)
        {
            db.Nominations.RemoveRange(staleSeedNominations);
            await db.SaveChangesAsync();
        }

        var orderedCategories = categories.Values
            .OrderBy(item => item.SortOrder)
            .ThenBy(item => item.Name)
            .ToArray();
        var candidatesByCategoryId = candidates
            .GroupBy(item => item.CategoryId)
            .ToDictionary(
                grouping => grouping.Key,
                grouping => grouping.OrderBy(item => item.DisplayName).ToArray());

        var seedNominations = new List<Nomination>();
        var createdAt = new DateTimeOffset(2026, 6, 22, 12, 0, 0, TimeSpan.Zero);

        foreach (var category in orderedCategories)
        {
            candidatesByCategoryId.TryGetValue(category.Id, out var categoryCandidates);
            var existingCandidate = categoryCandidates?.FirstOrDefault();

            seedNominations.AddRange(BuildPendingSeedGroup(
                category,
                existingCandidate,
                groupKey: "existing",
                firstSubmitter: $"seed_review_{category.Slug}_existing_a",
                secondSubmitter: $"seed_review_{category.Slug}_existing_b",
                createdAt,
                useSuggestedCategory: true,
                trackerStatus: "resolved"));
            createdAt = createdAt.AddMinutes(8);

            seedNominations.AddRange(BuildPendingSeedGroup(
                category,
                existingCandidate: null,
                groupKey: "fresh",
                firstSubmitter: $"seed_review_{category.Slug}_fresh_a",
                secondSubmitter: $"seed_review_{category.Slug}_fresh_b",
                createdAt,
                useSuggestedCategory: false,
                trackerStatus: "unsupported_platform"));
            createdAt = createdAt.AddMinutes(8);
        }

        foreach (var category in orderedCategories.Take(2))
        {
            seedNominations.AddRange(BuildReviewedSeedGroup(
                category,
                status: "rejected",
                displayName: $"{category.GroupName} Review Return",
                submittedByPrefix: $"seed_review_{category.Slug}_rejected",
                createdAt,
                reviewedByTwitchId: "jayuhime_admin",
                candidateId: null,
                candidateDisplayName: null));
            createdAt = createdAt.AddMinutes(10);
        }

        foreach (var category in orderedCategories.Skip(2).Take(2))
        {
            candidatesByCategoryId.TryGetValue(category.Id, out var categoryCandidates);
            var candidate = categoryCandidates?.FirstOrDefault();
            seedNominations.AddRange(BuildReviewedSeedGroup(
                category,
                status: "approved",
                displayName: candidate?.DisplayName ?? $"{category.GroupName} Approved Pick",
                submittedByPrefix: $"seed_review_{category.Slug}_approved",
                createdAt,
                reviewedByTwitchId: "jayuhime_admin",
                candidateId: candidate?.Id,
                candidateDisplayName: candidate?.DisplayName));
            createdAt = createdAt.AddMinutes(10);
        }

        db.Nominations.AddRange(seedNominations);
        await db.SaveChangesAsync();
    }

    private static IEnumerable<Nomination> BuildPendingSeedGroup(
        Category category,
        Candidate? existingCandidate,
        string groupKey,
        string firstSubmitter,
        string secondSubmitter,
        DateTimeOffset createdAt,
        bool useSuggestedCategory,
        string trackerStatus)
    {
        var displayName = existingCandidate?.DisplayName ?? BuildFreshSeedName(category, groupKey);
        var platform = existingCandidate?.Platform ?? "YouTube";
        var channelSlug = existingCandidate?.ChannelSlug ?? BuildSeedChannelSlug(category, groupKey);
        var streamUrl = BuildSeedStreamUrl(platform, channelSlug);
        var avgViewers = ResolveSeedViewerValue(category);
        int? suggestedCategoryId = useSuggestedCategory ? category.Id : null;

        yield return new Nomination
        {
            SeasonId = category.SeasonId,
            CategoryId = category.Id,
            CategoryGroupName = category.GroupName,
            SubmittedByTwitchId = firstSubmitter,
            CandidateText = displayName,
            StreamUrl = streamUrl,
            ResolvedChannel = channelSlug.TrimStart('@'),
            ResolvedPlatform = platform,
            AvgViewers = avgViewers,
            SuggestedCategoryId = suggestedCategoryId,
            TrackerStatus = trackerStatus,
            TrackerCheckedAt = createdAt.AddMinutes(2),
            TrackingReviewStatus = "clear",
            Status = "pending",
            CreatedAt = createdAt,
        };

        yield return new Nomination
        {
            SeasonId = category.SeasonId,
            CategoryId = category.Id,
            CategoryGroupName = category.GroupName,
            SubmittedByTwitchId = secondSubmitter,
            CandidateText = displayName,
            StreamUrl = streamUrl,
            ResolvedChannel = channelSlug.TrimStart('@'),
            ResolvedPlatform = platform,
            AvgViewers = avgViewers,
            SuggestedCategoryId = suggestedCategoryId,
            TrackerStatus = trackerStatus,
            TrackerCheckedAt = createdAt.AddMinutes(3),
            TrackingReviewStatus = "clear",
            Status = "pending",
            CreatedAt = createdAt.AddMinutes(1),
        };
    }

    private static IEnumerable<Nomination> BuildReviewedSeedGroup(
        Category category,
        string status,
        string displayName,
        string submittedByPrefix,
        DateTimeOffset createdAt,
        string reviewedByTwitchId,
        int? candidateId,
        string? candidateDisplayName)
    {
        var channelSlug = BuildSeedChannelSlug(category, $"{status}_{displayName}");
        var streamUrl = BuildSeedStreamUrl("Twitch", channelSlug);
        var reviewNote = status == "approved"
            ? "Seed-Datensatz: bereits als Kandidat übernommen."
            : "Seed-Datensatz: bewusst verworfen für Undo-Tests.";

        yield return new Nomination
        {
            SeasonId = category.SeasonId,
            CategoryId = category.Id,
            CategoryGroupName = category.GroupName,
            SubmittedByTwitchId = $"{submittedByPrefix}_a",
            CandidateId = candidateId,
            CandidateText = displayName,
            StreamUrl = streamUrl,
            ResolvedChannel = channelSlug.TrimStart('@'),
            ResolvedPlatform = "Twitch",
            AvgViewers = ResolveSeedViewerValue(category),
            SuggestedCategoryId = category.Id,
            TrackerStatus = "resolved",
            TrackerCheckedAt = createdAt.AddMinutes(2),
            TrackingReviewStatus = "reviewed",
            TrackingReviewNote = reviewNote,
            TrackingReviewedByTwitchId = reviewedByTwitchId,
            TrackingReviewedAt = createdAt.AddMinutes(4),
            Status = status,
            ReviewNote = reviewNote,
            ReviewedByTwitchId = reviewedByTwitchId,
            CreatedAt = createdAt,
            ReviewedAt = createdAt.AddMinutes(4),
        };

        yield return new Nomination
        {
            SeasonId = category.SeasonId,
            CategoryId = category.Id,
            CategoryGroupName = category.GroupName,
            SubmittedByTwitchId = $"{submittedByPrefix}_b",
            CandidateId = candidateId,
            CandidateText = displayName,
            StreamUrl = streamUrl,
            ResolvedChannel = channelSlug.TrimStart('@'),
            ResolvedPlatform = "Twitch",
            AvgViewers = ResolveSeedViewerValue(category),
            SuggestedCategoryId = category.Id,
            TrackerStatus = "resolved",
            TrackerCheckedAt = createdAt.AddMinutes(3),
            TrackingReviewStatus = "reviewed",
            TrackingReviewNote = reviewNote,
            TrackingReviewedByTwitchId = reviewedByTwitchId,
            TrackingReviewedAt = createdAt.AddMinutes(5),
            Status = status,
            ReviewNote = reviewNote,
            ReviewedByTwitchId = reviewedByTwitchId,
            CreatedAt = createdAt.AddMinutes(1),
            ReviewedAt = createdAt.AddMinutes(5),
        };
    }

    private static string BuildFreshSeedName(Category category, string groupKey) =>
        groupKey switch
        {
            "fresh" => $"{category.GroupName} Spotlight {category.Name}",
            _ => $"{category.GroupName} {category.Name} Pick",
        };

    private static string BuildSeedChannelSlug(Category category, string suffix)
    {
        var raw = $"{category.Slug}-{suffix}"
            .Trim()
            .TrimStart('@')
            .ToLowerInvariant();

        return new string(raw.Where(char.IsLetterOrDigit).ToArray());
    }

    private static string BuildSeedStreamUrl(string platform, string channelSlug) =>
        platform.Trim().ToLowerInvariant() switch
        {
            "youtube" => $"https://www.youtube.com/@{channelSlug}",
            "kick" => $"https://kick.com/{channelSlug}",
            "cake" => $"https://cake.gg/{channelSlug}",
            _ => $"https://www.twitch.tv/{channelSlug}",
        };

    private static int ResolveSeedViewerValue(Category category)
    {
        if (category.ViewerRangeMin is int min && category.ViewerRangeMax is int max)
        {
            return min + ((max - min) / 2);
        }

        if (category.ViewerRangeMin is int lowerBound)
        {
            return lowerBound + 12;
        }

        if (category.ViewerRangeMax is int upperBound)
        {
            return Math.Max(1, upperBound - 5);
        }

        return 25;
    }

    private sealed record LegacySeedState(bool HasRiskSeed, bool HasAuditSeed);
}