using Microsoft.EntityFrameworkCore;
using TakeoutSaaS.Domain.Identity.Entities;
using TakeoutSaaS.Domain.Identity.Repositories;

namespace TakeoutSaaS.Infrastructure.Identity.Persistence;

/// <summary>
/// 角色模板仓储实现。
/// </summary>
public sealed class EfRoleTemplateRepository(IdentityDbContext dbContext) : IRoleTemplateRepository
{
    public Task<IReadOnlyList<RoleTemplate>> GetAllAsync(bool? isActive, CancellationToken cancellationToken = default)
    {
        var query = dbContext.RoleTemplates.AsNoTracking();
        if (isActive.HasValue)
        {
            query = query.Where(x => x.IsActive == isActive.Value);
        }

        return query
            .OrderBy(x => x.TemplateCode)
            .ToListAsync(cancellationToken)
            .ContinueWith(t => (IReadOnlyList<RoleTemplate>)t.Result, cancellationToken);
    }

    public Task<RoleTemplate?> FindByCodeAsync(string templateCode, CancellationToken cancellationToken = default)
    {
        var normalized = templateCode.Trim();
        return dbContext.RoleTemplates.AsNoTracking().FirstOrDefaultAsync(x => x.TemplateCode == normalized, cancellationToken);
    }

    public Task<IReadOnlyList<RoleTemplatePermission>> GetPermissionsAsync(long roleTemplateId, CancellationToken cancellationToken = default)
    {
        return dbContext.RoleTemplatePermissions.AsNoTracking()
            .Where(x => x.RoleTemplateId == roleTemplateId)
            .ToListAsync(cancellationToken)
            .ContinueWith(t => (IReadOnlyList<RoleTemplatePermission>)t.Result, cancellationToken);
    }

    public async Task<IDictionary<long, IReadOnlyList<RoleTemplatePermission>>> GetPermissionsAsync(IEnumerable<long> roleTemplateIds, CancellationToken cancellationToken = default)
    {
        var ids = roleTemplateIds.Distinct().ToArray();
        if (ids.Length == 0)
        {
            return new Dictionary<long, IReadOnlyList<RoleTemplatePermission>>();
        }

        var permissions = await dbContext.RoleTemplatePermissions.AsNoTracking()
            .Where(x => ids.Contains(x.RoleTemplateId))
            .ToListAsync(cancellationToken);

        return permissions
            .GroupBy(x => x.RoleTemplateId)
            .ToDictionary(g => g.Key, g => (IReadOnlyList<RoleTemplatePermission>)g.ToList());
    }

    public async Task AddAsync(RoleTemplate template, IEnumerable<string> permissionCodes, CancellationToken cancellationToken = default)
    {
        template.TemplateCode = template.TemplateCode.Trim();
        template.Name = template.Name.Trim();
        await dbContext.RoleTemplates.AddAsync(template, cancellationToken);
        await ReplacePermissionsInternalAsync(template, permissionCodes, cancellationToken);
    }

    public async Task UpdateAsync(RoleTemplate template, IEnumerable<string> permissionCodes, CancellationToken cancellationToken = default)
    {
        template.TemplateCode = template.TemplateCode.Trim();
        template.Name = template.Name.Trim();
        dbContext.RoleTemplates.Update(template);
        await ReplacePermissionsInternalAsync(template, permissionCodes, cancellationToken);
    }

    public async Task DeleteAsync(long roleTemplateId, CancellationToken cancellationToken = default)
    {
        var entity = await dbContext.RoleTemplates.FirstOrDefaultAsync(x => x.Id == roleTemplateId, cancellationToken);
        if (entity != null)
        {
            var permissions = dbContext.RoleTemplatePermissions.Where(x => x.RoleTemplateId == roleTemplateId);
            dbContext.RoleTemplatePermissions.RemoveRange(permissions);
            dbContext.RoleTemplates.Remove(entity);
        }
    }

    public Task SaveChangesAsync(CancellationToken cancellationToken = default)
        => dbContext.SaveChangesAsync(cancellationToken);

    private async Task ReplacePermissionsInternalAsync(RoleTemplate template, IEnumerable<string> permissionCodes, CancellationToken cancellationToken)
    {
        var strategy = dbContext.Database.CreateExecutionStrategy();
        await strategy.ExecuteAsync(async () =>
        {
            await using var trx = await dbContext.Database.BeginTransactionAsync(cancellationToken);

            // 1. 确保模板已持久化，便于 FK 正确填充
            if (!dbContext.Entry(template).IsKeySet || template.Id == 0)
            {
                await dbContext.SaveChangesAsync(cancellationToken);
            }

            // 2. 归一化权限编码
            var normalized = permissionCodes
                .Where(code => !string.IsNullOrWhiteSpace(code))
                .Select(code => code.Trim())
                .Distinct(StringComparer.OrdinalIgnoreCase)
                .ToArray();

            // 3. 清空旧权限
            var existing = await dbContext.RoleTemplatePermissions
                .Where(x => x.RoleTemplateId == template.Id)
                .ToListAsync(cancellationToken);
            dbContext.RoleTemplatePermissions.RemoveRange(existing);
            await dbContext.SaveChangesAsync(cancellationToken);

            // 4. 插入新权限
            var toAdd = normalized.Select(code => new RoleTemplatePermission
            {
                RoleTemplateId = template.Id,
                PermissionCode = code
            });

            await dbContext.RoleTemplatePermissions.AddRangeAsync(toAdd, cancellationToken);
            await dbContext.SaveChangesAsync(cancellationToken);

            await trx.CommitAsync(cancellationToken);
        });
    }
}