@page "/diagnostics"
@implements IDisposable

<PageTitle>Database Configuration & Migrations - Chrono DB</PageTitle>

<div class="d-flex align-items-center justify-content-between mb-4">
    <div>
        <h2 class="fw-bold mb-1 text-white">Database Settings & Migrations</h2>
        <p class="text-secondary mb-0">Configure database providers, update connection strings, inspect EF Core migrations, and run maintenance tasks.</p>
    </div>
    <div class="d-flex gap-2">
        <button class="btn btn-chrono-secondary" @onclick="RefreshAsync">
            <i class="bi bi-arrow-clockwise"></i> Refresh Status
        </button>
    </div>
</div>

@if (!string.IsNullOrEmpty(alertMessage))
{
    <div class="alert @(alertIsSuccess ? "alert-success" : "alert-danger") alert-dismissible fade show" role="alert">
        <i class="bi @(alertIsSuccess ? "bi-check-circle-fill" : "bi-exclamation-triangle-fill") me-2"></i>
        @alertMessage
        <button type="button" class="btn-close" @onclick="() => alertMessage = null"></button>
    </div>
}

<div class="row g-4 mb-4">
    <!-- Connection Configuration -->
    <div class="col-lg-6">
        <div class="chrono-card h-100">
            <div class="chrono-card-header">
                <h5 class="chrono-card-title">
                    <i class="bi bi-hdd-network-fill text-primary"></i>
                    Database Provider & Connection
                </h5>
            </div>

            <div class="mb-3">
                <label class="form-label text-secondary small fw-bold">ACTIVE PROVIDER</label>
                <div class="d-flex gap-2">
                    <button class="btn flex-fill @(selectedProvider == DatabaseProviderType.PostgreSQL ? "btn-chrono-primary" : "btn-chrono-secondary")"
                            @onclick="() => SelectProvider(DatabaseProviderType.PostgreSQL)">
                        <i class="bi bi-database me-1"></i> PostgreSQL (Cloud DB)
                    </button>
                    <button class="btn flex-fill @(selectedProvider == DatabaseProviderType.InMemory ? "btn-chrono-primary" : "btn-chrono-secondary")"
                            @onclick="() => SelectProvider(DatabaseProviderType.InMemory)">
                        <i class="bi bi-cpu me-1"></i> In-Memory Test DB
                    </button>
                </div>
            </div>

            @if (selectedProvider == DatabaseProviderType.PostgreSQL)
            {
                <div class="mb-3">
                    <label class="form-label text-secondary small fw-bold">POSTGRESQL CONNECTION STRING</label>
                    <textarea class="form-control form-control-chrono font-monospace" rows="3"
                              placeholder="Host=localhost;Port=5432;Database=chrono;Username=postgres;Password=postgres"
                              @bind="connectionStringInput"></textarea>
                    <div class="form-text text-secondary">
                        Standard Npgsql connection string format used by <code>Cloud.AppDbContext</code>.
                    </div>
                </div>

                <div class="mb-3">
                    <label class="form-label text-secondary small fw-bold">CONNECTION PRESETS</label>
                    <div class="d-flex flex-wrap gap-2">
                        <button type="button" class="btn btn-sm btn-outline-secondary"
                                @onclick='() => SetPreset("Host=localhost;Port=5432;Database=chrono;Username=postgres;Password=postgres")'>
                            Default Localhost (5432)
                        </button>
                        <button type="button" class="btn btn-sm btn-outline-secondary"
                                @onclick='() => SetPreset("Host=host.docker.internal;Port=5432;Database=chrono;Username=postgres;Password=postgres")'>
                            Docker Host Internal
                        </button>
                    </div>
                </div>
            }
            else
            {
                <div class="mb-3">
                    <label class="form-label text-secondary small fw-bold">IN-MEMORY DATABASE INSTANCE NAME</label>
                    <input type="text" class="form-control form-control-chrono font-monospace"
                           @bind="inMemoryNameInput" />
                    <div class="form-text text-secondary">
                        In-memory EF Core provider creates an isolated database in RAM for instant testing.
                    </div>
                </div>
            }

            <div class="d-flex justify-content-end gap-2 mt-4">
                <button class="btn btn-chrono-primary" @onclick="SaveConfigurationAsync" disabled="@isSaving">
                    <i class="bi bi-check2-circle me-1"></i>
                    @(isSaving ? "Connecting..." : "Save & Test Connection")
                </button>
            </div>
        </div>
    </div>

    <!-- Live Database Diagnostics & Table Counts -->
    <div class="col-lg-6">
        <div class="chrono-card h-100">
            <div class="chrono-card-header">
                <h5 class="chrono-card-title">
                    <i class="bi bi-activity text-info"></i>
                    Database Health & Entity Counts
                </h5>
                <span class="badge @(health?.IsConnected == true ? "bg-success" : "bg-danger")">
                    @(health?.IsConnected == true ? "ONLINE" : "OFFLINE")
                </span>
            </div>

            @if (health != null)
            {
                <div class="d-flex flex-column gap-2 mb-4">
                    <div class="p-2 rounded bg-dark border border-secondary d-flex justify-content-between align-items-center">
                        <span class="text-secondary small">Connection Status</span>
                        <span class="fw-bold @(health.IsConnected ? "text-success" : "text-danger")">
                            @(health.IsConnected ? "Connected" : "Disconnected")
                        </span>
                    </div>

                    <div class="p-2 rounded bg-dark border border-secondary d-flex justify-content-between align-items-center">
                        <span class="text-secondary small">Query Latency</span>
                        <span class="text-white font-monospace">@(health.ResponseTimeMs) ms</span>
                    </div>

                    <div class="p-2 rounded bg-dark border border-secondary d-flex justify-content-between align-items-center">
                        <span class="text-secondary small">CardNotes Table Rows</span>
                        <span class="text-primary fw-bold">@health.CardNotesCount</span>
                    </div>

                    <div class="p-2 rounded bg-dark border border-secondary d-flex justify-content-between align-items-center">
                        <span class="text-secondary small">UserDecks Table Rows</span>
                        <span class="text-success fw-bold">@health.UserDecksCount</span>
                    </div>

                    <div class="p-2 rounded bg-dark border border-secondary d-flex justify-content-between align-items-center">
                        <span class="text-secondary small">PasskeyCredentials Table Rows</span>
                        <span class="text-purple fw-bold">@health.PasskeysCount</span>
                    </div>
                </div>

                @if (!health.IsConnected && !string.IsNullOrEmpty(health.ErrorMessage))
                {
                    <div class="alert alert-danger p-2 small mb-0">
                        <i class="bi bi-exclamation-triangle-fill me-1"></i>
                        @health.ErrorMessage
                    </div>
                }
            }
        </div>
    </div>
</div>

<!-- EF Core Migrations Section -->
<div class="chrono-card">
    <div class="chrono-card-header">
        <h5 class="chrono-card-title">
            <i class="bi bi-layer-forward text-warning"></i>
            EF Core Migrations Status
        </h5>
        @if (migrationReport?.SupportsMigrations == true && migrationReport.PendingMigrations.Any())
        {
            <button class="btn btn-chrono-primary btn-sm" @onclick="ApplyMigrationsAsync" disabled="@isActionBusy">
                <i class="bi bi-arrow-up-circle-fill me-1"></i> Apply Pending Migrations (@migrationReport.PendingMigrations.Count)
            </button>
        }
    </div>

    @if (migrationReport == null)
    {
        <div class="text-center py-4 text-secondary">
            <div class="spinner-border spinner-border-sm me-2" role="status"></div> Loading migration report...
        </div>
    }
    else if (!migrationReport.SupportsMigrations)
    {
        <div class="p-3 bg-dark rounded border border-secondary text-secondary small">
            <i class="bi bi-info-circle me-1"></i>
            Migrations are managed via relational schema (PostgreSQL). The active in-memory provider does not use relational migration tables.
        </div>
    }
    else
    {
        <div class="row g-4">
            <!-- Applied Migrations -->
            <div class="col-md-6">
                <h6 class="text-secondary small fw-bold mb-2">
                    <i class="bi bi-check2-all text-success me-1"></i>
                    APPLIED MIGRATIONS (@migrationReport.AppliedMigrations.Count)
                </h6>
                @if (!migrationReport.AppliedMigrations.Any())
                {
                    <div class="text-secondary small fst-italic p-2 bg-dark rounded border border-secondary">
                        No migrations have been applied to this database yet.
                    </div>
                }
                else
                {
                    <div class="d-flex flex-column gap-2" style="max-height: 250px; overflow-y: auto;">
                        @foreach (var m in migrationReport.AppliedMigrations)
                        {
                            <div class="p-2 rounded bg-dark border border-success border-opacity-50 d-flex align-items-center justify-content-between">
                                <span class="text-white small font-monospace">@m</span>
                                <span class="badge bg-success"><i class="bi bi-check"></i> Applied</span>
                            </div>
                        }
                    </div>
                }
            </div>

            <!-- Pending Migrations -->
            <div class="col-md-6">
                <h6 class="text-secondary small fw-bold mb-2">
                    <i class="bi bi-clock-history text-warning me-1"></i>
                    PENDING MIGRATIONS (@migrationReport.PendingMigrations.Count)
                </h6>
                @if (!migrationReport.PendingMigrations.Any())
                {
                    <div class="p-3 bg-dark rounded border border-success border-opacity-25 text-success small">
                        <i class="bi bi-shield-check me-1"></i> All migrations are applied. Schema is in sync with AppDbContext.
                    </div>
                }
                else
                {
                    <div class="d-flex flex-column gap-2" style="max-height: 250px; overflow-y: auto;">
                        @foreach (var m in migrationReport.PendingMigrations)
                        {
                            <div class="p-2 rounded bg-dark border border-warning border-opacity-50 d-flex align-items-center justify-content-between">
                                <span class="text-warning small font-monospace">@m</span>
                                <span class="badge bg-warning text-dark"><i class="bi bi-exclamation-triangle"></i> Pending</span>
                            </div>
                        }
                    </div>
                }
            </div>
        </div>
    }
</div>

<!-- Database Maintenance Section -->
<div class="chrono-card">
    <div class="chrono-card-header">
        <h5 class="chrono-card-title text-danger">
            <i class="bi bi-tools text-danger"></i>
            Database Maintenance & Tools
        </h5>
    </div>

    <div class="d-flex flex-wrap gap-3">
        <button class="btn btn-chrono-secondary" @onclick="SeedDataAsync" disabled="@isActionBusy">
            <i class="bi bi-box-arrow-in-down me-1"></i> Seed Realistic Sample Data
        </button>

        <button class="btn btn-chrono-danger" @onclick="ResetDatabaseAsync" disabled="@isActionBusy">
            <i class="bi bi-trash3-fill me-1"></i> Wipe / Reset All Tables
        </button>
    </div>
</div>

@code {
    private DatabaseHealthStatus? health;
    private MigrationReport? migrationReport;
    private DatabaseProviderType selectedProvider;
    private string connectionStringInput = "";
    private string inMemoryNameInput = "";
    private bool isSaving;
    private bool isActionBusy;
    private string? alertMessage;
    private bool alertIsSuccess;

    protected override async Task OnInitializedAsync()
    {
        ConfigService.OnConfigurationChanged += HandleConfigChanged;
        selectedProvider = ConfigService.ProviderType;
        connectionStringInput = ConfigService.ConnectionString;
        inMemoryNameInput = ConfigService.InMemoryDbName;
        await RefreshAsync();
    }

    private void HandleConfigChanged()
    {
        selectedProvider = ConfigService.ProviderType;
        connectionStringInput = ConfigService.ConnectionString;
        inMemoryNameInput = ConfigService.InMemoryDbName;
        _ = RefreshAsync();
    }

    private async Task RefreshAsync()
    {
        health = await DbService.CheckHealthAsync();
        migrationReport = await DbService.GetMigrationStatusAsync();
    }

    private void SelectProvider(DatabaseProviderType provider)
    {
        selectedProvider = provider;
    }

    private void SetPreset(string conn)
    {
        connectionStringInput = conn;
    }

    private async Task SaveConfigurationAsync()
    {
        isSaving = true;
        ConfigService.SetConnectionString(connectionStringInput);
        ConfigService.SetInMemoryDbName(inMemoryNameInput);
        ConfigService.SetProvider(selectedProvider);

        if (selectedProvider == DatabaseProviderType.InMemory)
        {
            await DbService.EnsureDatabaseCreatedAsync();
        }

        await RefreshAsync();
        isSaving = false;

        alertIsSuccess = health?.IsConnected == true;
        alertMessage = health?.IsConnected == true
            ? "Configuration updated successfully and connection verified."
            : $"Configuration updated, but connection failed: {health?.ErrorMessage}";
    }

    private async Task ApplyMigrationsAsync()
    {
        isActionBusy = true;
        var result = await DbService.ApplyMigrationsAsync();
        isActionBusy = false;
        alertIsSuccess = result.Success;
        alertMessage = result.Message;
        await RefreshAsync();
    }

    private async Task SeedDataAsync()
    {
        isActionBusy = true;
        var result = await DbService.SeedSampleDataAsync();
        isActionBusy = false;
        alertIsSuccess = result.Success;
        alertMessage = result.Message;
        await RefreshAsync();
    }

    private async Task ResetDatabaseAsync()
    {
        isActionBusy = true;
        var result = await DbService.ResetDatabaseAsync();
        isActionBusy = false;
        alertIsSuccess = result.Success;
        alertMessage = result.Message;
        await RefreshAsync();
    }

    public void Dispose()
    {
        ConfigService.OnConfigurationChanged -= HandleConfigChanged;
    }
}