using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using StellaOps.Auth.ServerIntegration.Tenancy;
using StellaOps.Localization;
using StellaOps.Platform.WebService.Constants;
using StellaOps.Platform.WebService.Services;

namespace StellaOps.Platform.WebService.Endpoints;

/// <summary>
/// REST API endpoints for translation management and serving UI bundles.
/// </summary>
public static class LocalizationEndpoints
{
    public static IEndpointRouteBuilder MapLocalizationEndpoints(this IEndpointRouteBuilder app)
    {
        // Anonymous UI bundle endpoint (same pattern as /platform/envsettings.json)
        app.MapGet("/platform/i18n/{locale}.json", async (
            string locale,
            HttpContext context,
            PlatformTranslationService translationService,
            CancellationToken ct) =>
        {
            var tenantId = context.Request.Headers["X-Tenant-Id"].FirstOrDefault() ?? "_system";
            var bundle = await translationService.GetMergedBundleAsync(tenantId, locale, ct);

            // Cache for 5 minutes — translations don't change often
            context.Response.Headers.CacheControl = "public, max-age=300";
            return Results.Ok(bundle);
        })
        .WithTags("Localization")
        .WithName("GetUiTranslationBundle")
        .WithSummary("Gets the merged translation bundle for the UI")
        .WithDescription(
            "Returns all translations for the specified locale, merging embedded defaults with DB overrides. " +
            "Anonymous access, cacheable. Used by the Angular frontend at boot time.")
        .AllowAnonymous();

        // Authenticated API group
        var group = app.MapGroup("/api/v1/platform/localization")
            .WithTags("Localization")
            .RequireAuthorization(PlatformPolicies.PreferencesRead)
            .RequireTenant();

        // Get all translations for a locale
        group.MapGet("/bundles/{locale}", async (
            string locale,
            HttpContext context,
            PlatformTranslationService translationService,
            CancellationToken ct) =>
        {
            var tenantId = context.Request.Headers["X-Tenant-Id"].FirstOrDefault() ?? "_system";
            var bundle = await translationService.GetMergedBundleAsync(tenantId, locale, ct);

            return Results.Ok(new
            {
                locale,
                strings = bundle,
                count = bundle.Count
            });
        })
        .WithName("GetTranslationBundle")
        .WithSummary("Gets all translations for a locale")
        .WithDescription(
            "Returns the merged set of all translations for the specified locale, " +
            "combining embedded defaults with system and tenant DB overrides in priority order.");

        // Get translations filtered by namespace
        group.MapGet("/bundles/{locale}/{ns}", async (
            string locale,
            string ns,
            HttpContext context,
            PlatformTranslationService translationService,
            CancellationToken ct) =>
        {
            var tenantId = context.Request.Headers["X-Tenant-Id"].FirstOrDefault() ?? "_system";
            var bundle = await translationService.GetMergedBundleAsync(tenantId, locale, ns, ct);

            return Results.Ok(new
            {
                locale,
                @namespace = ns,
                strings = bundle,
                count = bundle.Count
            });
        })
        .WithName("GetTranslationBundleByNamespace")
        .WithSummary("Gets translations for a locale filtered by namespace prefix");

        // Get available locales
        group.MapGet("/locales", async (
            HttpContext context,
            PlatformTranslationService translationService,
            CancellationToken ct) =>
        {
            var tenantId = context.Request.Headers["X-Tenant-Id"].FirstOrDefault() ?? "_system";
            var locales = await translationService.GetAllLocalesAsync(tenantId, ct);

            return Results.Ok(new
            {
                locales,
                count = locales.Count
            });
        })
        .WithName("GetAvailableLocales")
        .WithSummary("Gets all available locales");

        // Upsert translations (admin)
        group.MapPut("/bundles", async (
            UpsertTranslationsRequest request,
            HttpContext context,
            ITranslationStore store,
            TranslationRegistry registry,
            CancellationToken ct) =>
        {
            var tenantId = context.Request.Headers["X-Tenant-Id"].FirstOrDefault() ?? "_system";
            var actor = context.Request.Headers["X-Actor"].FirstOrDefault() ?? "system";

            if (string.IsNullOrWhiteSpace(request.Locale))
            {
                return Results.BadRequest(new { error = "Locale is required." });
            }

            if (request.Strings is null || request.Strings.Count == 0)
            {
                return Results.BadRequest(new { error = "At least one translation string is required." });
            }

            await store.UpsertBatchAsync(tenantId, request.Locale, request.Strings, actor, ct);

            // Also merge into the in-memory registry for immediate effect
            registry.MergeBundles(request.Locale, request.Strings);

            return Results.Ok(new
            {
                locale = request.Locale,
                upserted = request.Strings.Count,
                message = "Translations updated successfully."
            });
        })
        .WithName("UpsertTranslations")
        .WithSummary("Creates or updates translation strings")
        .WithDescription(
            "Upserts translation key-value pairs for a locale. DB values override embedded defaults. " +
            "Changes take immediate effect in the in-memory registry.")
        .RequireAuthorization(PlatformPolicies.PreferencesWrite);

        // Delete a translation (admin)
        group.MapDelete("/strings/{locale}/{key}", async (
            string locale,
            string key,
            HttpContext context,
            ITranslationStore store,
            CancellationToken ct) =>
        {
            var tenantId = context.Request.Headers["X-Tenant-Id"].FirstOrDefault() ?? "_system";

            var deleted = await store.DeleteAsync(tenantId, locale, key, ct);
            if (!deleted)
            {
                return Results.NotFound(new { error = $"Translation '{key}' not found for locale '{locale}'." });
            }

            return Results.Ok(new { message = $"Translation '{key}' deleted for locale '{locale}'." });
        })
        .WithName("DeleteTranslation")
        .WithSummary("Deletes a translation override")
        .RequireAuthorization(PlatformPolicies.PreferencesWrite);

        return app;
    }
}

/// <summary>
/// Request to upsert translations.
/// </summary>
public sealed record UpsertTranslationsRequest
{
    /// <summary>Target locale (e.g., "en-US", "de-DE").</summary>
    public required string Locale { get; init; }

    /// <summary>Key-value pairs to upsert.</summary>
    public required Dictionary<string, string> Strings { get; init; }
}