using System.Collections.Immutable;
using System.Globalization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using StellaOps.Excititor.WebService.Services;

namespace StellaOps.Excititor.WebService.Endpoints;

internal static class IngestEndpoints
{
    private const string AdminScope = "vex.admin";

    public static void MapIngestEndpoints(IEndpointRouteBuilder app)
    {
        var group = app.MapGroup("/excititor");

        group.MapPost("/init", HandleInitAsync);
        group.MapPost("/ingest/run", HandleRunAsync);
        group.MapPost("/ingest/resume", HandleResumeAsync);
        group.MapPost("/reconcile", HandleReconcileAsync);
    }

    internal static async Task<IResult> HandleInitAsync(
        HttpContext httpContext,
        ExcititorInitRequest request,
        IVexIngestOrchestrator orchestrator,
        TimeProvider timeProvider,
        CancellationToken cancellationToken)
    {
        var scopeResult = ScopeAuthorization.RequireScope(httpContext, AdminScope);
        if (scopeResult is not null)
        {
            return scopeResult;
        }

        var providerIds = NormalizeProviders(request.Providers);
        _ = timeProvider;
        var options = new IngestInitOptions(providerIds, request.Resume ?? false);

        var summary = await orchestrator.InitializeAsync(options, cancellationToken).ConfigureAwait(false);
        var message = $"Initialized {summary.ProviderCount} provider(s); {summary.SuccessCount} succeeded, {summary.FailureCount} failed.";

        return TypedResults.Ok<object>(new
        {
            message,
            runId = summary.RunId,
            startedAt = summary.StartedAt,
            completedAt = summary.CompletedAt,
            providers = summary.Providers.Select(static provider => new
            {
                providerId = provider.ProviderId,
                displayName = provider.DisplayName,
                status = provider.Status,
                durationMs = provider.Duration.TotalMilliseconds,
                error = provider.Error
            })
        });
    }

    internal static async Task<IResult> HandleRunAsync(
        HttpContext httpContext,
        ExcititorIngestRunRequest request,
        IVexIngestOrchestrator orchestrator,
        TimeProvider timeProvider,
        CancellationToken cancellationToken)
    {
        var scopeResult = ScopeAuthorization.RequireScope(httpContext, AdminScope);
        if (scopeResult is not null)
        {
            return scopeResult;
        }

        if (!TryParseDateTimeOffset(request.Since, out var since, out var sinceError))
        {
            return TypedResults.BadRequest<object>(new { message = sinceError });
        }

        if (!TryParseTimeSpan(request.Window, out var window, out var windowError))
        {
            return TypedResults.BadRequest<object>(new { message = windowError });
        }

        _ = timeProvider;
        var providerIds = NormalizeProviders(request.Providers);
        var options = new IngestRunOptions(
            providerIds,
            since,
            window,
            request.Force ?? false);

        var summary = await orchestrator.RunAsync(options, cancellationToken).ConfigureAwait(false);
        var message = $"Ingest run completed for {summary.ProviderCount} provider(s); {summary.SuccessCount} succeeded, {summary.FailureCount} failed.";

        return TypedResults.Ok<object>(new
        {
            message,
            runId = summary.RunId,
            startedAt = summary.StartedAt,
            completedAt = summary.CompletedAt,
            durationMs = summary.Duration.TotalMilliseconds,
            providers = summary.Providers.Select(static provider => new
            {
                providerId = provider.ProviderId,
                status = provider.Status,
                documents = provider.Documents,
                claims = provider.Claims,
                startedAt = provider.StartedAt,
                completedAt = provider.CompletedAt,
                durationMs = provider.Duration.TotalMilliseconds,
                lastDigest = provider.LastDigest,
                lastUpdated = provider.LastUpdated,
                checkpoint = provider.Checkpoint,
                error = provider.Error
            })
        });
    }

    internal static async Task<IResult> HandleResumeAsync(
        HttpContext httpContext,
        ExcititorIngestResumeRequest request,
        IVexIngestOrchestrator orchestrator,
        TimeProvider timeProvider,
        CancellationToken cancellationToken)
    {
        var scopeResult = ScopeAuthorization.RequireScope(httpContext, AdminScope);
        if (scopeResult is not null)
        {
            return scopeResult;
        }

        _ = timeProvider;
        var providerIds = NormalizeProviders(request.Providers);
        var options = new IngestResumeOptions(providerIds, request.Checkpoint);

        var summary = await orchestrator.ResumeAsync(options, cancellationToken).ConfigureAwait(false);
        var message = $"Resume run completed for {summary.ProviderCount} provider(s); {summary.SuccessCount} succeeded, {summary.FailureCount} failed.";

        return TypedResults.Ok<object>(new
        {
            message,
            runId = summary.RunId,
            startedAt = summary.StartedAt,
            completedAt = summary.CompletedAt,
            durationMs = summary.Duration.TotalMilliseconds,
            providers = summary.Providers.Select(static provider => new
            {
                providerId = provider.ProviderId,
                status = provider.Status,
                documents = provider.Documents,
                claims = provider.Claims,
                startedAt = provider.StartedAt,
                completedAt = provider.CompletedAt,
                durationMs = provider.Duration.TotalMilliseconds,
                since = provider.Since,
                checkpoint = provider.Checkpoint,
                error = provider.Error
            })
        });
    }

    internal static async Task<IResult> HandleReconcileAsync(
        HttpContext httpContext,
        ExcititorReconcileRequest request,
        IVexIngestOrchestrator orchestrator,
        TimeProvider timeProvider,
        CancellationToken cancellationToken)
    {
        var scopeResult = ScopeAuthorization.RequireScope(httpContext, AdminScope);
        if (scopeResult is not null)
        {
            return scopeResult;
        }

        if (!TryParseTimeSpan(request.MaxAge, out var maxAge, out var error))
        {
            return TypedResults.BadRequest<object>(new { message = error });
        }

        _ = timeProvider;
        var providerIds = NormalizeProviders(request.Providers);
        var options = new ReconcileOptions(providerIds, maxAge);

        var summary = await orchestrator.ReconcileAsync(options, cancellationToken).ConfigureAwait(false);
        var message = $"Reconcile completed for {summary.ProviderCount} provider(s); {summary.ReconciledCount} reconciled, {summary.SkippedCount} skipped, {summary.FailureCount} failed.";

        return TypedResults.Ok<object>(new
        {
            message,
            runId = summary.RunId,
            startedAt = summary.StartedAt,
            completedAt = summary.CompletedAt,
            durationMs = summary.Duration.TotalMilliseconds,
            providers = summary.Providers.Select(static provider => new
            {
                providerId = provider.ProviderId,
                status = provider.Status,
                action = provider.Action,
                lastUpdated = provider.LastUpdated,
                threshold = provider.Threshold,
                documents = provider.Documents,
                claims = provider.Claims,
                error = provider.Error
            })
        });
    }

    internal static ImmutableArray<string> NormalizeProviders(IReadOnlyCollection<string>? providers)
    {
        if (providers is null || providers.Count == 0)
        {
            return ImmutableArray<string>.Empty;
        }

        var set = new SortedSet<string>(StringComparer.OrdinalIgnoreCase);
        foreach (var provider in providers)
        {
            if (string.IsNullOrWhiteSpace(provider))
            {
                continue;
            }

            set.Add(provider.Trim());
        }

        return set.ToImmutableArray();
    }

    internal static bool TryParseDateTimeOffset(string? value, out DateTimeOffset? result, out string? error)
    {
        result = null;
        error = null;

        if (string.IsNullOrWhiteSpace(value))
        {
            return true;
        }

        if (DateTimeOffset.TryParse(
            value.Trim(),
            CultureInfo.InvariantCulture,
            DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal,
            out var parsed))
        {
            result = parsed;
            return true;
        }

        error = "Invalid 'since' value. Use ISO-8601 format (e.g. 2025-10-19T12:30:00Z).";
        return false;
    }

    internal static bool TryParseTimeSpan(string? value, out TimeSpan? result, out string? error)
    {
        result = null;
        error = null;

        if (string.IsNullOrWhiteSpace(value))
        {
            return true;
        }

        if (TimeSpan.TryParse(value.Trim(), CultureInfo.InvariantCulture, out var parsed) && parsed >= TimeSpan.Zero)
        {
            result = parsed;
            return true;
        }

        error = "Invalid duration value. Use TimeSpan format (e.g. 1.00:00:00).";
        return false;
    }

    internal sealed record ExcititorInitRequest(IReadOnlyList<string>? Providers, bool? Resume);

    internal sealed record ExcititorIngestRunRequest(
        IReadOnlyList<string>? Providers,
        string? Since,
        string? Window,
        bool? Force);

    internal sealed record ExcititorIngestResumeRequest(
        IReadOnlyList<string>? Providers,
        string? Checkpoint);

    internal sealed record ExcititorReconcileRequest(
        IReadOnlyList<string>? Providers,
        string? MaxAge);
}