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

namespace Gott.Endpoints;

public static class SkillEndpoint
{
    private static readonly Dictionary<string, string> MimeTypes = new(StringComparer.OrdinalIgnoreCase)
    {
        { ".png", "image/png" }, { ".jpg", "image/jpeg" }, { ".jpeg", "image/jpeg" },
        { ".gif", "image/gif" }, { ".webp", "image/webp" }, { ".svg", "image/svg+xml" },
        { ".bmp", "image/bmp" }, { ".ico", "image/x-icon" },
        { ".pdf", "application/pdf" },
        { ".mp4", "video/mp4" }, { ".webm", "video/webm" },
        { ".mp3", "audio/mpeg" }, { ".wav", "audio/wav" }, { ".ogg", "audio/ogg" },
    };

    public static void MapSkillEndpoints(this IEndpointRouteBuilder app)
    {
        // Skills (Dateisystem-basiert)
        app.MapGet("/api/skills", HandleListSkills);

        // Skill-Output-Dateien (Bilder etc.)
        app.MapGet("/api/skills/{slug}/output/{filename}", HandleSkillOutput);

        // Thumbnail (gecached)
        app.MapGet("/api/skills/{slug}/output/{filename}/thumb", HandleSkillOutputThumb);

        // Agent ↔ Skill Zuordnung
        app.MapGet("/api/agents/{agentId}/skills", HandleGetAgentSkills);
        app.MapPut("/api/agents/{agentId}/skills", HandleSetAgentSkills);
        app.MapPost("/api/agents/{agentId}/skills/{slug}", HandleAddAgentSkill);
        app.MapDelete("/api/agents/{agentId}/skills/{slug}", HandleRemoveAgentSkill);
    }

    private static async Task HandleListSkills(HttpContext ctx, SkillService skillService)
    {
        var skills = skillService.GetAllSkills();
        await ctx.Response.WriteAsJsonAsync(skills);
    }

    private static async Task<bool> VerifyAgentOwner(HttpContext ctx, DatabaseService db, string agentId)
    {
        if (string.IsNullOrEmpty(agentId)) return false;
        var agent = await db.GetAgent(agentId);
        return agent != null && agent.UserId == ctx.GetUserId();
    }

    private static async Task HandleGetAgentSkills(HttpContext ctx, DatabaseService db, SkillService skillService)
    {
        var agentId = ctx.Request.RouteValues["agentId"]?.ToString();
        if (string.IsNullOrEmpty(agentId) || !await VerifyAgentOwner(ctx, db, agentId)) { ctx.Response.StatusCode = 400; return; }

        var slugs = await db.GetAgentSkills(agentId);
        var allSkills = skillService.GetAllSkills();

        // Nur Skills zurückgeben die auch wirklich existieren
        var result = allSkills
            .Where(s => slugs.Contains(s.Slug))
            .ToList();

        await ctx.Response.WriteAsJsonAsync(result);
    }

    private static async Task HandleSetAgentSkills(HttpContext ctx, DatabaseService db)
    {
        var agentId = ctx.Request.RouteValues["agentId"]?.ToString();
        if (string.IsNullOrEmpty(agentId) || !await VerifyAgentOwner(ctx, db, agentId)) { ctx.Response.StatusCode = 400; return; }

        var body = await JsonSerializer.DeserializeAsync<JsonElement>(ctx.Request.Body);
        var slugs = body.TryGetProperty("skills", out var arr)
            ? arr.EnumerateArray().Select(e => e.GetString()).Where(s => !string.IsNullOrEmpty(s)).ToList()
            : new System.Collections.Generic.List<string>();

        await db.SetAgentSkills(agentId, slugs);

        var updated = await db.GetAgentSkills(agentId);
        await ctx.Response.WriteAsJsonAsync(updated);
    }

    private static async Task HandleAddAgentSkill(HttpContext ctx, DatabaseService db)
    {
        var agentId = ctx.Request.RouteValues["agentId"]?.ToString();
        var slug = ctx.Request.RouteValues["slug"]?.ToString();
        if (string.IsNullOrEmpty(agentId) || string.IsNullOrEmpty(slug) || !await VerifyAgentOwner(ctx, db, agentId)) { ctx.Response.StatusCode = 400; return; }

        await db.AddAgentSkill(agentId, slug);
        ctx.Response.StatusCode = 204;
    }

    private static async Task HandleRemoveAgentSkill(HttpContext ctx, DatabaseService db)
    {
        var agentId = ctx.Request.RouteValues["agentId"]?.ToString();
        var slug = ctx.Request.RouteValues["slug"]?.ToString();
        if (string.IsNullOrEmpty(agentId) || string.IsNullOrEmpty(slug) || !await VerifyAgentOwner(ctx, db, agentId)) { ctx.Response.StatusCode = 400; return; }

        await db.RemoveAgentSkill(agentId, slug);
        ctx.Response.StatusCode = 204;
    }

    private static async Task HandleSkillOutput(HttpContext ctx, SkillService skillService)
    {
        var slug = ctx.Request.RouteValues["slug"]?.ToString();
        var filename = ctx.Request.RouteValues["filename"]?.ToString();

        if (string.IsNullOrEmpty(slug) || string.IsNullOrEmpty(filename))
        {
            ctx.Response.StatusCode = 400;
            return;
        }

        // Sicherheit: Keine Pfad-Traversals erlauben
        if (filename.Contains("..") || filename.Contains('/') || filename.Contains('\\'))
        {
            ctx.Response.StatusCode = 400;
            return;
        }

        var skill = skillService.GetSkill(slug);
        if (skill == null)
        {
            ctx.Response.StatusCode = 404;
            return;
        }

        var filePath = Path.Combine(skill.Path, "output", filename);
        if (!File.Exists(filePath))
        {
            ctx.Response.StatusCode = 404;
            return;
        }

        var ext = Path.GetExtension(filename);
        var contentType = MimeTypes.GetValueOrDefault(ext, "application/octet-stream");

        ctx.Response.ContentType = contentType;
        ctx.Response.Headers["Cache-Control"] = "private, max-age=3600";
        await ctx.Response.SendFileAsync(filePath);
    }

    private static readonly HashSet<string> ThumbExtensions = new(StringComparer.OrdinalIgnoreCase)
    {
        ".png", ".jpg", ".jpeg", ".gif", ".webp", ".bmp"
    };

    private static async Task HandleSkillOutputThumb(HttpContext ctx, SkillService skillService)
    {
        var slug = ctx.Request.RouteValues["slug"]?.ToString();
        var filename = ctx.Request.RouteValues["filename"]?.ToString();

        if (string.IsNullOrEmpty(slug) || string.IsNullOrEmpty(filename))
        {
            ctx.Response.StatusCode = 400;
            return;
        }

        if (filename.Contains("..") || filename.Contains('/') || filename.Contains('\\'))
        {
            ctx.Response.StatusCode = 400;
            return;
        }

        var ext = Path.GetExtension(filename);
        if (!ThumbExtensions.Contains(ext))
        {
            ctx.Response.StatusCode = 400;
            await ctx.Response.WriteAsync("Thumbnails nur für Bilder verfügbar");
            return;
        }

        var skill = skillService.GetSkill(slug);
        if (skill == null) { ctx.Response.StatusCode = 404; return; }

        var originalPath = Path.Combine(skill.Path, "output", filename);
        if (!File.Exists(originalPath)) { ctx.Response.StatusCode = 404; return; }

        var dataDir = Path.GetDirectoryName(skillService.SkillsDir);
        var cacheDir = Path.Combine(dataDir, "cache", "skills", slug);

        var thumbPath = await ImageService.GenerateThumbnail(originalPath, cacheDir);
        if (thumbPath != null)
        {
            ctx.Response.ContentType = "image/webp";
            ctx.Response.Headers["Cache-Control"] = "private, max-age=86400";
            await ctx.Response.SendFileAsync(thumbPath);
        }
        else
        {
            // Fallback: Original ausliefern
            ctx.Response.ContentType = MimeTypes.GetValueOrDefault(ext, "application/octet-stream");
            ctx.Response.Headers["Cache-Control"] = "private, max-age=3600";
            await ctx.Response.SendFileAsync(originalPath);
        }
    }
}