using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Routing;
using StellaOps.Platform.WebService.Constants;
using StellaOps.Platform.WebService.Contracts;
using StellaOps.Platform.WebService.Services;
using System;
using System.Linq;

namespace StellaOps.Platform.WebService.Endpoints;

public static class ContextEndpoints
{
    public static IEndpointRouteBuilder MapContextEndpoints(this IEndpointRouteBuilder app)
    {
        var context = app.MapGroup("/api/v2/context")
            .WithTags("Platform Context");

        context.MapGet("/regions", async Task<IResult>(
            HttpContext httpContext,
            PlatformRequestContextResolver resolver,
            PlatformContextService service,
            CancellationToken cancellationToken) =>
        {
            if (!TryResolveContext(httpContext, resolver, out _, out var failure))
            {
                return failure!;
            }

            var regions = await service.GetRegionsAsync(cancellationToken).ConfigureAwait(false);
            return Results.Ok(regions);
        })
        .WithName("GetPlatformContextRegions")
        .WithSummary("List global regions for context selection")
        .RequireAuthorization(PlatformPolicies.ContextRead);

        context.MapGet("/environments", async Task<IResult>(
            HttpContext httpContext,
            PlatformRequestContextResolver resolver,
            PlatformContextService service,
            [FromQuery(Name = "regions")] string? regions,
            CancellationToken cancellationToken) =>
        {
            if (!TryResolveContext(httpContext, resolver, out _, out var failure))
            {
                return failure!;
            }

            var regionFilter = ParseCsv(regions);
            var environments = await service.GetEnvironmentsAsync(regionFilter, cancellationToken).ConfigureAwait(false);
            return Results.Ok(environments);
        })
        .WithName("GetPlatformContextEnvironments")
        .WithSummary("List global environments with optional region filter")
        .RequireAuthorization(PlatformPolicies.ContextRead);

        context.MapGet("/preferences", async Task<IResult>(
            HttpContext httpContext,
            PlatformRequestContextResolver resolver,
            PlatformContextService service,
            CancellationToken cancellationToken) =>
        {
            if (!TryResolveContext(httpContext, resolver, out var requestContext, out var failure))
            {
                return failure!;
            }

            var preferences = await service.GetPreferencesAsync(requestContext!, cancellationToken).ConfigureAwait(false);
            return Results.Ok(preferences);
        })
        .WithName("GetPlatformContextPreferences")
        .WithSummary("Get persisted context preferences for the current user")
        .RequireAuthorization(PlatformPolicies.ContextRead);

        context.MapPut("/preferences", async Task<IResult>(
            HttpContext httpContext,
            PlatformRequestContextResolver resolver,
            PlatformContextService service,
            PlatformContextPreferencesRequest request,
            CancellationToken cancellationToken) =>
        {
            if (!TryResolveContext(httpContext, resolver, out var requestContext, out var failure))
            {
                return failure!;
            }

            var preferences = await service.UpsertPreferencesAsync(
                requestContext!,
                request,
                cancellationToken).ConfigureAwait(false);

            return Results.Ok(preferences);
        })
        .WithName("UpdatePlatformContextPreferences")
        .WithSummary("Update persisted context preferences for the current user")
        .RequireAuthorization(PlatformPolicies.ContextWrite);

        return app;
    }

    private static string[] ParseCsv(string? value)
    {
        if (string.IsNullOrWhiteSpace(value))
        {
            return Array.Empty<string>();
        }

        return value
            .Split(',', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
            .Where(item => !string.IsNullOrWhiteSpace(item))
            .Select(item => item.Trim().ToLowerInvariant())
            .Distinct(StringComparer.Ordinal)
            .ToArray();
    }

    private static bool TryResolveContext(
        HttpContext context,
        PlatformRequestContextResolver resolver,
        out PlatformRequestContext? requestContext,
        out IResult? failure)
    {
        if (resolver.TryResolve(context, out requestContext, out var error))
        {
            failure = null;
            return true;
        }

        failure = Results.BadRequest(new { error = error ?? "tenant_missing" });
        return false;
    }
}