// -----------------------------------------------------------------------------
// TileEndpoints.cs
// Sprint: SPRINT_20260125_002_Attestor_trust_automation
// Task: PROXY-002 - Implement tile-proxy service
// Description: Tile proxy API endpoints
// -----------------------------------------------------------------------------


using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Routing;
using StellaOps.Attestor.TileProxy.Services;
using System.Text.Json;

namespace StellaOps.Attestor.TileProxy.Endpoints;

/// <summary>
/// API endpoints for tile proxy service.
/// </summary>
public static class TileEndpoints
{
    /// <summary>
    /// Maps all tile proxy endpoints.
    /// </summary>
    public static IEndpointRouteBuilder MapTileProxyEndpoints(this IEndpointRouteBuilder endpoints)
    {
        // Tile endpoints (passthrough)
        endpoints.MapGet("/tile/{level:int}/{index:long}", GetTile)
            .WithName("GetTile")
            .WithTags("Tiles")
            .Produces<byte[]>(StatusCodes.Status200OK, "application/octet-stream")
            .Produces(StatusCodes.Status404NotFound)
            .Produces(StatusCodes.Status502BadGateway);

        endpoints.MapGet("/tile/{level:int}/{index:long}.p/{partialWidth:int}", GetPartialTile)
            .WithName("GetPartialTile")
            .WithTags("Tiles")
            .Produces<byte[]>(StatusCodes.Status200OK, "application/octet-stream")
            .Produces(StatusCodes.Status404NotFound)
            .Produces(StatusCodes.Status502BadGateway);

        // Checkpoint endpoint
        endpoints.MapGet("/checkpoint", GetCheckpoint)
            .WithName("GetCheckpoint")
            .WithTags("Checkpoint")
            .Produces<string>(StatusCodes.Status200OK, "text/plain")
            .Produces(StatusCodes.Status502BadGateway);

        // Admin endpoints
        var admin = endpoints.MapGroup("/_admin");

        admin.MapGet("/cache/stats", GetCacheStats)
            .WithName("GetCacheStats")
            .WithTags("Admin")
            .Produces<CacheStatsResponse>(StatusCodes.Status200OK);

        admin.MapGet("/metrics", GetMetrics)
            .WithName("GetMetrics")
            .WithTags("Admin")
            .Produces<MetricsResponse>(StatusCodes.Status200OK);

        admin.MapPost("/cache/sync", TriggerSync)
            .WithName("TriggerSync")
            .WithTags("Admin")
            .Produces<SyncResponse>(StatusCodes.Status200OK);

        admin.MapDelete("/cache/prune", PruneCache)
            .WithName("PruneCache")
            .WithTags("Admin")
            .Produces<PruneResponse>(StatusCodes.Status200OK);

        admin.MapGet("/health", HealthCheck)
            .WithName("HealthCheck")
            .WithTags("Admin")
            .Produces<HealthResponse>(StatusCodes.Status200OK);

        admin.MapGet("/ready", ReadinessCheck)
            .WithName("ReadinessCheck")
            .WithTags("Admin")
            .Produces(StatusCodes.Status200OK)
            .Produces(StatusCodes.Status503ServiceUnavailable);

        return endpoints;
    }

    private static async Task<IResult> GetTile(
        int level,
        long index,
        [FromServices] TileProxyService proxyService,
        CancellationToken cancellationToken)
    {
        var result = await proxyService.GetTileAsync(level, index, cancellationToken: cancellationToken);

        if (!result.Success)
        {
            return Results.Problem(
                detail: result.Error,
                statusCode: StatusCodes.Status502BadGateway);
        }

        if (result.Content == null)
        {
            return Results.NotFound();
        }

        return Results.Bytes(result.Content, "application/octet-stream");
    }

    private static async Task<IResult> GetPartialTile(
        int level,
        long index,
        int partialWidth,
        [FromServices] TileProxyService proxyService,
        CancellationToken cancellationToken)
    {
        if (partialWidth <= 0 || partialWidth > 256)
        {
            return Results.BadRequest("Invalid partial width");
        }

        var result = await proxyService.GetTileAsync(level, index, partialWidth, cancellationToken);

        if (!result.Success)
        {
            return Results.Problem(
                detail: result.Error,
                statusCode: StatusCodes.Status502BadGateway);
        }

        if (result.Content == null)
        {
            return Results.NotFound();
        }

        return Results.Bytes(result.Content, "application/octet-stream");
    }

    private static async Task<IResult> GetCheckpoint(
        [FromServices] TileProxyService proxyService,
        CancellationToken cancellationToken)
    {
        var result = await proxyService.GetCheckpointAsync(cancellationToken);

        if (!result.Success)
        {
            return Results.Problem(
                detail: result.Error,
                statusCode: StatusCodes.Status502BadGateway);
        }

        return Results.Text(result.Content ?? "", "text/plain");
    }

    private static async Task<IResult> GetCacheStats(
        [FromServices] ContentAddressedTileStore tileStore,
        CancellationToken cancellationToken)
    {
        var stats = await tileStore.GetStatsAsync(cancellationToken);

        return Results.Ok(new CacheStatsResponse
        {
            TotalTiles = stats.TotalTiles,
            TotalBytes = stats.TotalBytes,
            TotalMb = Math.Round(stats.TotalBytes / (1024.0 * 1024.0), 2),
            PartialTiles = stats.PartialTiles,
            UsagePercent = Math.Round(stats.UsagePercent, 2),
            OldestTile = stats.OldestTile,
            NewestTile = stats.NewestTile
        });
    }

    private static IResult GetMetrics(
        [FromServices] TileProxyService proxyService)
    {
        var metrics = proxyService.GetMetrics();

        return Results.Ok(new MetricsResponse
        {
            CacheHits = metrics.CacheHits,
            CacheMisses = metrics.CacheMisses,
            HitRatePercent = Math.Round(metrics.HitRate, 2),
            UpstreamRequests = metrics.UpstreamRequests,
            UpstreamErrors = metrics.UpstreamErrors,
            InflightRequests = metrics.InflightRequests
        });
    }

    private static IResult TriggerSync(
        [FromServices] IServiceProvider services,
        [FromServices] ILogger<TileEndpoints> logger)
    {
        // TODO: Trigger background sync job
        logger.LogInformation("Manual sync triggered");

        return Results.Ok(new SyncResponse
        {
            Message = "Sync job queued",
            QueuedAt = DateTimeOffset.UtcNow
        });
    }

    private static async Task<IResult> PruneCache(
        [FromServices] ContentAddressedTileStore tileStore,
        [FromQuery] long? targetSizeBytes,
        CancellationToken cancellationToken)
    {
        var prunedCount = await tileStore.PruneAsync(targetSizeBytes ?? 0, cancellationToken);

        return Results.Ok(new PruneResponse
        {
            TilesPruned = prunedCount,
            PrunedAt = DateTimeOffset.UtcNow
        });
    }

    private static IResult HealthCheck()
    {
        return Results.Ok(new HealthResponse
        {
            Status = "healthy",
            Timestamp = DateTimeOffset.UtcNow
        });
    }

    private static async Task<IResult> ReadinessCheck(
        [FromServices] TileProxyService proxyService,
        CancellationToken cancellationToken)
    {
        // Check if we can reach upstream
        var checkpoint = await proxyService.GetCheckpointAsync(cancellationToken);

        if (checkpoint.Success)
        {
            return Results.Ok(new { ready = true, checkpoint = checkpoint.TreeSize });
        }

        return Results.Json(
            new { ready = false, error = checkpoint.Error },
            statusCode: StatusCodes.Status503ServiceUnavailable);
    }
}

// Response models
public sealed record CacheStatsResponse
{
    public int TotalTiles { get; init; }
    public long TotalBytes { get; init; }
    public double TotalMb { get; init; }
    public int PartialTiles { get; init; }
    public double UsagePercent { get; init; }
    public DateTimeOffset? OldestTile { get; init; }
    public DateTimeOffset? NewestTile { get; init; }
}

public sealed record MetricsResponse
{
    public long CacheHits { get; init; }
    public long CacheMisses { get; init; }
    public double HitRatePercent { get; init; }
    public long UpstreamRequests { get; init; }
    public long UpstreamErrors { get; init; }
    public int InflightRequests { get; init; }
}

public sealed record SyncResponse
{
    public string Message { get; init; } = string.Empty;
    public DateTimeOffset QueuedAt { get; init; }
}

public sealed record PruneResponse
{
    public int TilesPruned { get; init; }
    public DateTimeOffset PrunedAt { get; init; }
}

public sealed record HealthResponse
{
    public string Status { get; init; } = string.Empty;
    public DateTimeOffset Timestamp { get; init; }
}

// Logger class for endpoint logging
file static class TileEndpoints
{
}