using Microsoft.EntityFrameworkCore;
using Tau.Acuvim.Portal.Configuration;
using Tau.Acuvim.Portal.Data;

namespace Tau.Acuvim.Portal.Services;

// Startup-time validation that prevents the obvious "pointed dev at prod DB" /
// "Admin mode against a Client DB" mistakes.
public static class RunModeGuards
{
    public static void ValidateConfig(ApplicationOptions app, DatabaseOptions database, FleetIngestOptions fleet)
    {
        if (app.RunMode == RunMode.Admin)
        {
            if (string.IsNullOrWhiteSpace(database.ConnectionString))
            {
                throw new InvalidOperationException(
                    "RunMode=Admin requires Database:ConnectionString. " +
                    "AutoProvisionLocalTimescaleDb is not honoured for Admin (no obvious local default for a fleet DB).");
            }
        }

        if (app.RunMode == RunMode.Client && fleet.Enabled)
        {
            if (string.IsNullOrWhiteSpace(fleet.Url) || string.IsNullOrWhiteSpace(fleet.Token))
            {
                throw new InvalidOperationException(
                    "FleetIngest:Enabled=true requires both FleetIngest:Url and FleetIngest:Token. " +
                    "Disable FleetIngest or provide both via env vars / secrets.");
            }
        }
    }

    // Refuse to run Client against an Admin DB (fleet.Customers exists) or vice versa.
    // Cheap query — only runs once at startup.
    public static async Task ValidateDatabaseShapeAsync(
        IServiceProvider services,
        RunMode runMode,
        CancellationToken ct = default)
    {
        using var scope = services.CreateScope();

        if (runMode == RunMode.Client)
        {
            var db = scope.ServiceProvider.GetService<AppDbContext>();
            if (db is null) return;
            try
            {
                var hasFleet = await db.Database
                    .SqlQuery<int>($@"SELECT 1 AS ""Value"" FROM information_schema.tables WHERE table_schema='fleet' AND table_name='Customers' LIMIT 1")
                    .ToListAsync(ct);
                if (hasFleet.Count > 0)
                {
                    throw new InvalidOperationException(
                        "RunMode=Client is pointed at a database that contains fleet.Customers (an Admin DB). " +
                        "Check Database:ConnectionString.");
                }
            }
            catch (Microsoft.EntityFrameworkCore.DbUpdateException) { /* db not ready, migration runs next */ }
        }
        else
        {
            var db = scope.ServiceProvider.GetService<AdminDbContext>();
            if (db is null) return;
            try
            {
                var hasMonitoring = await db.Database
                    .SqlQuery<int>($@"SELECT 1 AS ""Value"" FROM information_schema.tables WHERE table_schema='monitoring' AND table_name='PowerMeasurements' LIMIT 1")
                    .ToListAsync(ct);
                if (hasMonitoring.Count > 0)
                {
                    throw new InvalidOperationException(
                        "RunMode=Admin is pointed at a database that contains monitoring.PowerMeasurements (a Client DB). " +
                        "Check Database:ConnectionString.");
                }
            }
            catch (Microsoft.EntityFrameworkCore.DbUpdateException) { /* db not ready */ }
        }
    }
}