using Microsoft.Extensions.Configuration;
using ZB.MOM.WW.LocalDb;
using ZB.MOM.WW.ScadaBridge.SiteEventLogging;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Persistence;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Tracking;
using ZB.MOM.WW.ScadaBridge.StoreAndForward;

namespace ZB.MOM.WW.ScadaBridge.Host;

/// <summary>
/// Initializes the consolidated site database — the single <c>ZB.MOM.WW.LocalDb</c>-managed
/// file that holds the site node's replicated state.
/// </summary>
/// <remarks>
/// <para>
/// <b>Ordering is load-bearing.</b> Table DDL must run BEFORE
/// <c>RegisterReplicated</c>, and every row that should replicate must be written
/// AFTER it. Capture is trigger-based change-data-capture: the library neither
/// captures nor snapshots rows that already existed when the triggers were installed,
/// so a row written before registration is invisible to the peer forever — silently,
/// with no error anywhere.
/// </para>
/// <para>
/// Runs inside the <c>AddZbLocalDb</c> onReady callback, once, before any caller
/// receives the <see cref="ILocalDb"/> singleton. onReady is a synchronous
/// <c>Action&lt;ILocalDb&gt;</c>, hence the direct <c>CreateConnection()</c> rather than
/// blocking on the async execute API. A throw here propagates out of the first
/// <c>GetRequiredService&lt;ILocalDb&gt;()</c> and fails host startup, which is the
/// intent: a site node that cannot establish its schema must not come up half-working.
/// </para>
/// </remarks>
public static class SiteLocalDbSetup
{
    /// <summary>
    /// Creates the site node's replicated tables, opts them into change capture, and
    /// migrates any pre-Phase-1 databases in.
    /// </summary>
    /// <param name="db">The LocalDb instance being initialized.</param>
    /// <param name="config">Configuration, for the legacy migrator's old path keys and node name.</param>
    public static void OnReady(ILocalDb db, IConfiguration config)
    {
        ArgumentNullException.ThrowIfNull(db);
        ArgumentNullException.ThrowIfNull(config);

        using (var connection = db.CreateConnection())
        {
            OperationTrackingSchema.Apply(connection);
            SiteEventLogSchema.Apply(connection);

            // Phase 2: the site's configuration tables and the store-and-forward buffer
            // now live in this file too.
            SiteStorageSchema.Apply(connection);
            StoreAndForwardSchema.Apply(connection);
        }

        // Both tables qualify: each has an explicit primary key (RegisterReplicated
        // rejects tables without one) and no BLOB columns (which json_object cannot
        // capture). Registration is idempotent and installs the capture triggers.
        db.RegisterReplicated("OperationTracking");
        db.RegisterReplicated("site_events");

        // Phase 2: the store-and-forward buffer and the seven site configuration tables.
        // These replaced the bespoke SiteReplicationActor and StoreAndForward
        // ReplicationService, which shipped hand-written Add/Remove/Park/Requeue operations
        // over Akka; both were deleted in the same commit that added these lines, so the
        // two mechanisms never ran at once.
        //
        // Both composite-PK tables are fine: RegisterReplicated orders multi-column PKs by
        // ordinal. No Phase 2 table has a BLOB column, which it would reject.
        db.RegisterReplicated("sf_messages");
        db.RegisterReplicated("deployed_configurations");
        db.RegisterReplicated("static_attribute_overrides");
        db.RegisterReplicated("shared_scripts");
        db.RegisterReplicated("external_systems");
        db.RegisterReplicated("database_connections");
        db.RegisterReplicated("data_connection_definitions");
        db.RegisterReplicated("native_alarm_state");

        // notification_lists and smtp_configurations are created but deliberately NOT
        // registered. They are permanently empty by design — the site-side write paths were
        // removed on 2026-07-10, the legacy migrator skips them, and the active node's
        // artifact apply purges them on every deploy. Registering them would open a standing
        // replication channel whose only historical payload was plaintext SMTP passwords, in
        // exchange for replicating nothing. Anyone adding them here should first establish
        // that a site has a legitimate reason to hold SMTP credentials at all.

        // AFTER registration, so migrated rows enter the oplog and reach the peer like
        // any other write. Before it, they would be invisible to replication forever.
        SiteLocalDbLegacyMigrator.Migrate(db, config);
    }
}