using Distribution.Data;
using Distribution.Models;
using Microsoft.EntityFrameworkCore;

namespace Distribution.Features.Stock;

public class StockRepository(AppDBContext db) : IStockRepository
{
    public Task<StockBalance?> GetBalanceAsync(Guid itemId, Guid locationId) =>
        db.StockBalances
            .Include(b => b.Item)
            .FirstOrDefaultAsync(b => b.FK_ItemId == itemId && b.LocationId == locationId
                && b.FK_ItemBatchId == null && b.FK_ItemSerialNumberId == null);

    public Task<StockBalance?> GetBalanceAsync(Guid itemId, Guid locationId, Guid? itemBatchId, Guid? itemSerialNumberId) =>
        db.StockBalances
            .Include(b => b.Item)
            .FirstOrDefaultAsync(b => b.FK_ItemId == itemId && b.LocationId == locationId
                && b.FK_ItemBatchId == itemBatchId && b.FK_ItemSerialNumberId == itemSerialNumberId);

    public Task<List<StockBalance>> GetBalancesByLocationAsync(Guid locationId, LocationType locationType) =>
        db.StockBalances
            .Include(b => b.Item)
            .Where(b => b.LocationId == locationId && b.LocationType == locationType)
            .ToListAsync();

    public Task<List<StockBalance>> GetBalancesAsync(Guid? locationId, LocationType? locationType, Guid? itemId, int page, int pageSize)
    {
        var query = db.StockBalances.Include(b => b.Item).AsQueryable();
        if (locationId.HasValue) query = query.Where(b => b.LocationId == locationId.Value);
        if (locationType.HasValue) query = query.Where(b => b.LocationType == locationType.Value);
        if (itemId.HasValue) query = query.Where(b => b.FK_ItemId == itemId.Value);
        return query.Skip((page - 1) * pageSize).Take(pageSize).ToListAsync();
    }

    public Task<int> GetBalancesCountAsync(Guid? locationId, LocationType? locationType, Guid? itemId)
    {
        var query = db.StockBalances.AsQueryable();
        if (locationId.HasValue) query = query.Where(b => b.LocationId == locationId.Value);
        if (locationType.HasValue) query = query.Where(b => b.LocationType == locationType.Value);
        if (itemId.HasValue) query = query.Where(b => b.FK_ItemId == itemId.Value);
        return query.CountAsync();
    }

    public Task<List<StockBalance>> GetBalancesByItemAsync(Guid itemId) =>
        db.StockBalances
            .Include(b => b.Item)
            .Where(b => b.FK_ItemId == itemId)
            .ToListAsync();

    public Task<List<StockBalance>> GetLowStockAsync(Guid? locationId)
    {
        var query = db.StockBalances
            .Include(b => b.Item)
            .Where(b => b.LocationType == LocationType.Warehouse
                && b.Item.ReorderLevel != null
                && b.Quantity < b.Item.ReorderLevel);
        if (locationId.HasValue) query = query.Where(b => b.LocationId == locationId.Value);
        return query.OrderBy(b => b.Quantity).ToListAsync();
    }

    public async Task AddBalanceAsync(StockBalance balance) =>
        await db.StockBalances.AddAsync(balance);

    public void UpdateBalance(StockBalance balance) =>
        db.StockBalances.Update(balance);

    public async Task AddMovementAsync(StockMovement movement) =>
        await db.StockMovements.AddAsync(movement);

    public Task<StockMovement?> GetMovementByIdAsync(Guid id) =>
        db.StockMovements.Include(m => m.Item).FirstOrDefaultAsync(m => m.Id == id);

    public void UpdateMovement(StockMovement movement) =>
        db.StockMovements.Update(movement);

    public Task<List<StockMovement>> GetMovementsAsync(Guid? locationId, Guid? itemId, MovementType? type, DateTime? from, DateTime? to, int page, int pageSize)
    {
        var query = db.StockMovements.Include(m => m.Item).AsQueryable();
        if (locationId.HasValue)
            query = query.Where(m => m.FromLocationId == locationId.Value || m.ToLocationId == locationId.Value);
        if (itemId.HasValue) query = query.Where(m => m.FK_ItemId == itemId.Value);
        if (type.HasValue) query = query.Where(m => m.Type == type.Value);
        if (from.HasValue) query = query.Where(m => m.CreatedAt >= from.Value);
        if (to.HasValue) query = query.Where(m => m.CreatedAt <= to.Value);
        return query.OrderByDescending(m => m.CreatedAt).Skip((page - 1) * pageSize).Take(pageSize).ToListAsync();
    }

    public Task<int> GetMovementsCountAsync(Guid? locationId, Guid? itemId, MovementType? type, DateTime? from, DateTime? to)
    {
        var query = db.StockMovements.AsQueryable();
        if (locationId.HasValue)
            query = query.Where(m => m.FromLocationId == locationId.Value || m.ToLocationId == locationId.Value);
        if (itemId.HasValue) query = query.Where(m => m.FK_ItemId == itemId.Value);
        if (type.HasValue) query = query.Where(m => m.Type == type.Value);
        if (from.HasValue) query = query.Where(m => m.CreatedAt >= from.Value);
        if (to.HasValue) query = query.Where(m => m.CreatedAt <= to.Value);
        return query.CountAsync();
    }

    public Task<ItemBatch?> FindBatchAsync(Guid itemId, string batchNumber) =>
        db.ItemBatches.FirstOrDefaultAsync(b => b.FK_ItemId == itemId && b.BatchNumber == batchNumber);

    public async Task AddItemBatchAsync(ItemBatch batch) =>
        await db.ItemBatches.AddAsync(batch);

    public Task<bool> SerialNumberExistsAsync(Guid itemId, string serialNumber) =>
        db.ItemSerialNumbers.AnyAsync(s => s.FK_ItemId == itemId && s.SerialNumber == serialNumber);

    public async Task<int> GetNextSerialSequenceAsync(Guid itemId, string prefix)
    {
        // Only serials of the form <prefix><digits> count; anything else (a supplier's own serial that
        // happens to start with the prefix) is ignored for numbering.
        var serials = await db.ItemSerialNumbers
            .AsNoTracking()
            .Where(s => s.FK_ItemId == itemId && s.SerialNumber.StartsWith(prefix))
            .Select(s => s.SerialNumber)
            .ToListAsync();

        var max = 0L;
        foreach (var serial in serials)
        {
            var suffix = serial[prefix.Length..];
            if (suffix.Length is > 0 and <= 9 && suffix.All(char.IsDigit) && long.TryParse(suffix, out var n))
                max = Math.Max(max, n);
        }
        return (int)max + 1;
    }

    public async Task AddItemSerialNumberAsync(ItemSerialNumber serial) =>
        await db.ItemSerialNumbers.AddAsync(serial);
}