using Flurl.Http;
using InnovEnergy.App.Backend.Database;
using InnovEnergy.App.Backend.DataTypes;
using Newtonsoft.Json;

namespace InnovEnergy.App.Backend.Services;

/// <summary>
/// Generates AI-powered diagnoses for support tickets.
/// Runs async after ticket creation; stores result in TicketAiDiagnosis table.
/// </summary>
public static class TicketDiagnosticService
{
    private static string _apiKey = "";
    private static readonly string MistralUrl = "https://api.mistral.ai/v1/chat/completions";

    public static void Initialize()
    {
        var apiKey = Environment.GetEnvironmentVariable("MISTRAL_API_KEY");
        if (string.IsNullOrWhiteSpace(apiKey))
            Console.Error.WriteLine("[TicketDiagnosticService] MISTRAL_API_KEY not set – ticket AI disabled.");
        else
            _apiKey = apiKey;

        Console.WriteLine("[TicketDiagnosticService] initialised.");
    }

    public static bool IsEnabled => !string.IsNullOrEmpty(_apiKey);

    /// <summary>
    /// Called fire-and-forget after ticket creation.
    /// Creates a TicketAiDiagnosis row (Pending → Analyzing → Completed | Failed).
    /// </summary>
    public static async Task DiagnoseTicketAsync(Int64 ticketId)
    {
        var ticket = Db.GetTicketById(ticketId);
        if (ticket is null) return;

        var installation = Db.GetInstallationById(ticket.InstallationId);
        if (installation is null) return;

        var diagnosis = new TicketAiDiagnosis
        {
            TicketId  = ticketId,
            Status    = (Int32)DiagnosisStatus.Pending,
            CreatedAt = DateTime.UtcNow
        };
        Db.Create(diagnosis);

        if (!IsEnabled)
        {
            diagnosis.Status = (Int32)DiagnosisStatus.Failed;
            Db.Update(diagnosis);
            return;
        }

        diagnosis.Status = (Int32)DiagnosisStatus.Analyzing;
        Db.Update(diagnosis);

        try
        {
            var productName = ((ProductType)installation.Product).ToString();

            var recentErrors = Db.Errors
                .Where(e => e.InstallationId == ticket.InstallationId)
                .OrderByDescending(e => e.Date)
                .ToList()
                .Select(e => e.Description)
                .Distinct()
                .Take(5)
                .ToList();

            var prompt = BuildPrompt(ticket, productName, recentErrors);
            var result = await CallMistralAsync(prompt);

            if (result is null)
            {
                diagnosis.Status = (Int32)DiagnosisStatus.Failed;
            }
            else
            {
                diagnosis.Status             = (Int32)DiagnosisStatus.Completed;
                diagnosis.RootCause          = result.RootCause;
                diagnosis.Confidence         = result.Confidence;
                diagnosis.RecommendedActions = result.RecommendedActionsJson;
                diagnosis.CompletedAt        = DateTime.UtcNow;
            }
        }
        catch (Exception ex)
        {
            Console.Error.WriteLine($"[TicketDiagnosticService] {ex.Message}");
            diagnosis.Status = (Int32)DiagnosisStatus.Failed;
        }

        Db.Update(diagnosis);

        Db.Create(new TicketTimelineEvent
        {
            TicketId    = ticketId,
            EventType   = (Int32)TimelineEventType.AiDiagnosisAttached,
            Description = diagnosis.Status == (Int32)DiagnosisStatus.Completed
                ? "AI diagnosis completed."
                : "AI diagnosis failed.",
            ActorType   = (Int32)TimelineActorType.AiAgent,
            CreatedAt   = DateTime.UtcNow
        });
    }

    private static string BuildPrompt(Ticket ticket, string productName, List<string> recentErrors)
    {
        var recentList = recentErrors.Count > 0
            ? string.Join(", ", recentErrors)
            : "none";

        return $@"You are a senior field technician for {productName} battery energy storage systems.
A support ticket has been submitted with the following details:
Subject: {ticket.Subject}
Description: {ticket.Description}
Category: {(TicketCategory)ticket.Category}
Priority: {(TicketPriority)ticket.Priority}
Recent system alarms: {recentList}

Analyze this ticket and respond in JSON only — no markdown, no explanation outside JSON:
{{
  ""rootCause"": ""One concise sentence describing the most likely root cause."",
  ""confidence"": 0.85,
  ""recommendedActions"": [""Action 1"", ""Action 2"", ""Action 3""]
}}
Confidence must be a number between 0.0 and 1.0.";
    }

    private static async Task<TicketDiagnosisResult?> CallMistralAsync(string prompt)
    {
        try
        {
            var body = new
            {
                model       = "mistral-small-latest",
                messages    = new[] { new { role = "user", content = prompt } },
                max_tokens  = 300,
                temperature = 0.2
            };

            var text = await MistralUrl
                .WithHeader("Authorization", $"Bearer {_apiKey}")
                .PostJsonAsync(body)
                .ReceiveString();

            var envelope = JsonConvert.DeserializeObject<dynamic>(text);
            var content  = (string?)envelope?.choices?[0]?.message?.content;

            if (string.IsNullOrWhiteSpace(content)) return null;

            var json = content.Trim();
            if (json.StartsWith("```"))
            {
                var nl = json.IndexOf('\n');
                if (nl >= 0) json = json[(nl + 1)..];
                if (json.EndsWith("```")) json = json[..^3];
                json = json.Trim();
            }

            var parsed = JsonConvert.DeserializeObject<TicketDiagnosisRaw>(json);
            if (parsed is null) return null;

            return new TicketDiagnosisResult
            {
                RootCause            = parsed.RootCause,
                Confidence           = parsed.Confidence,
                RecommendedActionsJson = JsonConvert.SerializeObject(parsed.RecommendedActions ?? Array.Empty<string>())
            };
        }
        catch (Exception ex)
        {
            Console.Error.WriteLine($"[TicketDiagnosticService] HTTP error: {ex.Message}");
            return null;
        }
    }
}

internal class TicketDiagnosisRaw
{
    [JsonProperty("rootCause")]
    public String? RootCause { get; set; }

    [JsonProperty("confidence")]
    public Double? Confidence { get; set; }

    [JsonProperty("recommendedActions")]
    public String[]? RecommendedActions { get; set; }
}

internal class TicketDiagnosisResult
{
    public String?  RootCause              { get; set; }
    public Double?  Confidence             { get; set; }
    public String?  RecommendedActionsJson { get; set; }
}