using Bifrost.Web.Configuration;
using Bifrost.Web.Data;
using Bifrost.Web.Domain;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Options;

namespace Bifrost.Web.Features.Shared;

public sealed class ApplicationBootstrapper(
    BifrostDbContext dbContext,
    IOptions<BootstrapOptions> bootstrapOptions,
    TimeProvider timeProvider,
    AuditTrailService auditTrailService,
    ILogger<ApplicationBootstrapper> logger)
{
    public async Task RunAsync(CancellationToken cancellationToken)
    {
        if (dbContext.Database.IsRelational() && bootstrapOptions.Value.ApplyMigrationsOnStartup)
        {
            logger.LogInformation("Applying database migrations on startup.");
            await dbContext.Database.MigrateAsync(cancellationToken);
        }

        var adminLogins = bootstrapOptions.Value.AdminGitHubLogins
            .Where(x => !string.IsNullOrWhiteSpace(x))
            .Select(x => x.Trim().ToUpperInvariant())
            .Distinct()
            .ToArray();

        if (adminLogins.Length == 0)
        {
            return;
        }

        var now = timeProvider.GetUtcNow();
        var adminUsers = await dbContext.UserAccounts
            .Include(x => x.Membership!)
                .ThenInclude(x => x.RoleAssignments)
            .Where(x => adminLogins.Contains(x.NormalizedGitHubLogin))
            .ToListAsync(cancellationToken);

        foreach (var adminUser in adminUsers.Where(x => x.Membership is not null))
        {
            var before = adminUser.Membership!.Status;
            if (TryPromoteBootstrapAdmin(adminUser, now, logger) && before != adminUser.Membership.Status)
            {
                await RecordPromotionAsync(auditTrailService, adminUser, before, cancellationToken);
            }
        }

        if (dbContext.ChangeTracker.HasChanges())
        {
            await dbContext.SaveChangesAsync(cancellationToken);
        }
    }

    /// <summary>
    /// The one bootstrap-admin promotion, used at startup and at sign-in. A Merged or Suspended account is left exactly as it is (an admin's
    /// decision; only the suspension service lifts it) and the refusal is logged by account id. Returns whether it promoted.
    /// </summary>
    public static bool TryPromoteBootstrapAdmin(UserAccount account, DateTimeOffset now, ILogger logger)
    {
        var membership = account.Membership!;
        if (membership.IsMerged)
        {
            logger.LogWarning("Bootstrap admin promotion skipped for merged account {UserAccountId}.", account.Id);
            return false;
        }

        if (membership.Status == MembershipStatus.Suspended)
        {
            logger.LogWarning("Bootstrap admin promotion skipped for suspended account {UserAccountId}.", account.Id);
            return false;
        }

        membership.Status = MembershipStatus.Active;
        membership.IsPlatformAdmin = true;
        membership.CanManageProjects = true;
        membership.CanManageLedger = true;
        membership.CanModerateMotions = true;
        membership.ApprovedAtUtc ??= now;

        EnsureRole(membership, MemberRole.PlatformAdmin, null, now, "Bootstrap admin");
        EnsureRole(membership, MemberRole.StandardMember, null, now, "Default active member role");
        return true;
    }

    /// <summary>The receipt for a bootstrap promotion that changed membership status; saves together with the promotion.</summary>
    public static Task RecordPromotionAsync(AuditTrailService auditTrailService, UserAccount account, MembershipStatus before, CancellationToken cancellationToken) =>
        auditTrailService.RecordAsync(
            null,
            nameof(Bifrost.Web.Domain.Membership),
            account.Membership!.Id,
            "membership.bootstrap-promoted",
            $"Bootstrap admin promotion of {account.DisplayName} ({before} -> {account.Membership.Status}).",
            cancellationToken);

    public static void EnsureRole(
        Bifrost.Web.Domain.Membership membership,
        MemberRole role,
        Guid? actorUserAccountId,
        DateTimeOffset assignedAtUtc,
        string note)
    {
        if (membership.RoleAssignments.Any(x => x.Role == role))
        {
            return;
        }

        membership.RoleAssignments.Add(new RoleAssignment
        {
            Role = role,
            AssignedByUserAccountId = actorUserAccountId,
            AssignedAtUtc = assignedAtUtc,
            Notes = note
        });
    }
}