using Marathon.Application.Abstractions;
using Marathon.Application.Storage;
using Marathon.Domain.Entities;
using Marathon.Domain.ValueObjects;
using Microsoft.EntityFrameworkCore;

namespace Marathon.Infrastructure.Persistence.Repositories;

internal sealed class EventRepository : IEventRepository
{
    private readonly MarathonDbContext _db;

    public EventRepository(MarathonDbContext db) => _db = db;

    public async Task<Event?> GetAsync(EventId key, CancellationToken ct = default)
    {
        var entity = await _db.Events.FindAsync([key.Value], ct);
        return entity is null ? null : Mapping.ToDomain(entity);
    }

    public async Task<IReadOnlyList<Event>> ListAsync(CancellationToken ct = default)
    {
        var entities = await _db.Events.AsNoTracking().ToListAsync(ct);
        return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
    }

    public async Task<IReadOnlyList<Event>> ListByDateRangeAsync(DateRange range, CancellationToken ct = default)
    {
        // ScheduledAt is stored as ISO 8601 TEXT (see SqliteDateText); SQLite TEXT
        // comparison sorts chronologically for the fixed-offset O format.
        var fromStr = SqliteDateText.Key(range.From);
        var toStr = SqliteDateText.Key(range.To);

        // EF Core SQLite cannot translate string.Compare(...) with StringComparison; it can
        // translate the relational operators on string columns (which use BINARY/ordinal
        // collation by default in SQLite — correct for ISO 8601).
        var entities = await _db.Events.AsNoTracking()
            .Where(e => e.ScheduledAt.CompareTo(fromStr) >= 0
                     && e.ScheduledAt.CompareTo(toStr) <= 0)
            .ToListAsync(ct);

        return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
    }

    public async Task<IReadOnlyList<Event>> QueryAsync(EventQuery query, CancellationToken ct = default)
    {
        ArgumentNullException.ThrowIfNull(query);

        var fromStr = SqliteDateText.Key(query.Dates.From);
        var toStr = SqliteDateText.Key(query.Dates.To);

        // Date range + sport filter pushed to SQL so a multi-sport page no longer
        // materialises every event in the window. The composite
        // IX_Events_SportCode_ScheduledAt index covers this predicate. Case-sensitive
        // search / country filtering and locale-aware sorting stay in the service
        // layer where Cyrillic ordinal semantics are preserved.
        var q = _db.Events.AsNoTracking()
            .Where(e => e.ScheduledAt.CompareTo(fromStr) >= 0
                     && e.ScheduledAt.CompareTo(toStr) <= 0);

        if (query.SportCodes is { Count: > 0 } sports)
        {
            var sportArray = sports.Distinct().ToArray();
            q = q.Where(e => sportArray.Contains(e.SportCode));
        }

        var entities = await q.ToListAsync(ct);
        return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
    }

    public async Task<IReadOnlyDictionary<EventId, Event>> GetManyAsync(
        IReadOnlyCollection<EventId> ids,
        CancellationToken ct = default)
    {
        ArgumentNullException.ThrowIfNull(ids);

        var result = new Dictionary<EventId, Event>(ids.Count);
        if (ids.Count == 0)
            return result;

        var codes = ids.Select(e => e.Value).Distinct().ToArray();

        var entities = await _db.Events.AsNoTracking()
            .Where(e => codes.Contains(e.EventCode))
            .ToListAsync(ct);

        foreach (var entity in entities)
        {
            var domain = Mapping.ToDomain(entity);
            result[domain.Id] = domain;
        }

        return result;
    }

    public async Task<IReadOnlyList<Event>> ListBySportAsync(SportCode sport, CancellationToken ct = default)
    {
        var entities = await _db.Events.AsNoTracking()
            .Where(e => e.SportCode == sport.Value)
            .ToListAsync(ct);

        return entities.Select(Mapping.ToDomain).ToList().AsReadOnly();
    }

    public Task<int> CountAsync(CancellationToken ct = default) =>
        _db.Events.AsNoTracking().CountAsync(ct);

    public async Task<IReadOnlyList<int>> ListDistinctSportCodesAsync(CancellationToken ct = default)
    {
        var codes = await _db.Events.AsNoTracking()
            .Select(e => e.SportCode)
            .Distinct()
            .ToListAsync(ct);

        codes.Sort();
        return codes;
    }

    public async Task<IReadOnlyList<string>> ListDistinctCountryCodesAsync(CancellationToken ct = default)
    {
        var codes = await _db.Events.AsNoTracking()
            .Select(e => e.CountryCode)
            .Distinct()
            .ToListAsync(ct);

        codes.Sort(StringComparer.OrdinalIgnoreCase);
        return codes;
    }

    public async Task AddAsync(Event entity, CancellationToken ct = default)
    {
        var efEntity = Mapping.ToEntity(entity);
        await _db.Events.AddAsync(efEntity, ct);
    }

    public Task UpdateAsync(Event entity, CancellationToken ct = default)
    {
        var efEntity = Mapping.ToEntity(entity);
        _db.Events.Update(efEntity);
        return Task.CompletedTask;
    }

    public async Task DeleteAsync(EventId key, CancellationToken ct = default)
    {
        var entity = await _db.Events.FindAsync([key.Value], ct);
        if (entity is not null)
            _db.Events.Remove(entity);
    }

    public async Task SaveChangesAsync(CancellationToken ct = default) =>
        await _db.SaveChangesAsync(ct);
}