using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.Json;
using System.Threading.Tasks;
using Gott.Extensions;
using Gott.Models;
using Gott.Services;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;

namespace Gott.Endpoints;

public static class SharedEndpoint
{
    public static void MapSharedEndpoints(this IEndpointRouteBuilder app)
    {
        // Authentifizierte Endpunkte
        app.MapPost("/api/messages/{messageId}/share", HandleShareMessage);
        app.MapGet("/api/shared", HandleListShares);
        app.MapDelete("/api/shared/{token}", HandleDeleteShare);

        // Öffentlicher Endpunkt (Auth-Ausnahme in Middleware)
        app.MapGet("/api/shared/{token}", HandleGetShared);
    }

    private static async Task HandleShareMessage(HttpContext ctx, DatabaseService db)
    {
        var userId = ctx.GetUserId();
        var messageIdStr = ctx.Request.RouteValues["messageId"]?.ToString();
        if (!long.TryParse(messageIdStr, out var messageId))
        {
            ctx.Response.StatusCode = 400;
            await ctx.Response.WriteAsJsonAsync(new { error = "Invalid messageId" });
            return;
        }

        // Body lesen (optional: includeContext)
        bool includeContext = false;
        try
        {
            var body = await JsonSerializer.DeserializeAsync<JsonElement>(ctx.Request.Body);
            if (body.TryGetProperty("includeContext", out var ic)) includeContext = ic.GetBoolean();
        }
        catch { /* kein Body oder ungültig – defaults verwenden */ }

        // Nachricht existiert und gehört dem User?
        var message = await db.GetMessage(messageId);
        if (message == null)
        {
            ctx.Response.StatusCode = 404;
            await ctx.Response.WriteAsJsonAsync(new { error = "Message not found" });
            return;
        }

        // Chain holen → Session prüfen
        var chain = await db.GetChain(message.ChainId);
        if (chain == null)
        {
            ctx.Response.StatusCode = 404;
            await ctx.Response.WriteAsJsonAsync(new { error = "Chain not found" });
            return;
        }

        var session = await db.GetSession(chain.SessionId);
        if (session == null || session.UserId != userId)
        {
            ctx.Response.StatusCode = 403;
            await ctx.Response.WriteAsJsonAsync(new { error = "Not authorized" });
            return;
        }

        var shared = await db.CreateSharedMessage(messageId, userId, includeContext);
        await ctx.Response.WriteAsJsonAsync(new { token = shared.ShareToken });
    }

    private static async Task HandleGetShared(HttpContext ctx, DatabaseService db)
    {
        var token = ctx.Request.RouteValues["token"]?.ToString();
        if (string.IsNullOrEmpty(token))
        {
            ctx.Response.StatusCode = 400;
            return;
        }

        var shared = await db.GetSharedMessage(token);
        if (shared == null)
        {
            ctx.Response.StatusCode = 404;
            await ctx.Response.WriteAsJsonAsync(new { error = "Share not found" });
            return;
        }

        // Ablaufdatum prüfen
        if (!string.IsNullOrEmpty(shared.ExpiresAt) &&
            DateTime.TryParse(shared.ExpiresAt, out var expires) &&
            expires < DateTime.UtcNow)
        {
            ctx.Response.StatusCode = 410;
            await ctx.Response.WriteAsJsonAsync(new { error = "Share expired" });
            return;
        }

        var message = await db.GetMessage(shared.MessageId);
        if (message == null)
        {
            ctx.Response.StatusCode = 404;
            await ctx.Response.WriteAsJsonAsync(new { error = "Message not found" });
            return;
        }

        // Chain-Info holen
        var chain = await db.GetChain(message.ChainId);

        if (shared.IncludeContext)
        {
            // Alle Messages der Chain bis zu dieser Nachricht laden
            var contextMessages = await db.GetChainMessagesUpTo(message.ChainId, shared.MessageId);

            // Text- und Web-Search-Messages zurückgeben (keine tool_use/tool_result)
            var allowedTypes = new HashSet<string> { "text", "web_search_result" };
            var textMessages = contextMessages
                .Where(m => allowedTypes.Contains(m.Type) && m.DeletedOn == null)
                .Select(m => new
                {
                    m.Id,
                    m.Role,
                    m.Type,
                    m.Content,
                    m.CreatedAt,
                    m.Iteration
                })
                .ToList();

            await ctx.Response.WriteAsJsonAsync(new
            {
                mode = "context",
                messages = textMessages,
                model = chain?.Model,
                createdAt = shared.CreatedAt
            });
        }
        else
        {
            // Einzelne Nachricht
            await ctx.Response.WriteAsJsonAsync(new
            {
                mode = "single",
                message = new
                {
                    message.Id,
                    message.Role,
                    message.Content,
                    message.CreatedAt
                },
                model = chain?.Model,
                createdAt = shared.CreatedAt
            });
        }
    }

    private static async Task HandleListShares(HttpContext ctx, DatabaseService db)
    {
        var userId = ctx.GetUserId();
        var shares = await db.GetSharedMessagesByUser(userId);

        var result = new List<object>();
        foreach (var s in shares)
        {
            var message = await db.GetMessage(s.MessageId);
            string sessionName = null;
            if (message != null)
            {
                var chain = await db.GetChain(message.ChainId);
                if (chain != null)
                {
                    var session = await db.GetSession(chain.SessionId);
                    sessionName = session?.Name;
                }
            }

            var preview = message?.Content ?? "";
            if (preview.Length > 150) preview = preview.Substring(0, 150) + "…";

            result.Add(new
            {
                s.ShareToken,
                s.MessageId,
                s.IncludeContext,
                s.CreatedAt,
                role = message?.Role,
                preview,
                sessionName
            });
        }

        await ctx.Response.WriteAsJsonAsync(result);
    }

    private static async Task HandleDeleteShare(HttpContext ctx, DatabaseService db)
    {
        var userId = ctx.GetUserId();
        var token = ctx.Request.RouteValues["token"]?.ToString();
        if (string.IsNullOrEmpty(token))
        {
            ctx.Response.StatusCode = 400;
            return;
        }

        await db.DeleteSharedMessage(token, userId);
        ctx.Response.StatusCode = 204;
    }
}