using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using DSharpPlus;
using DSharpPlus.Entities;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
using Newtonsoft.Json.Linq;
using Newtonsoft.Json.Serialization;

namespace SupportChild;

public static class Interviewer
{
    public enum QuestionType
    {
        FAIL,
        DONE,
        BUTTONS,
        SELECTOR,
        TEXT_INPUT
    }

    // A tree of questions representing an interview.
    // The tree is generated by the config file when a new ticket is opened or the restart interview command is used.
    // Additional components not specified in the config file are populated as the interview progresses.
    // The entire interview tree is serialized and stored in the database in order to record responses as they are made.
    public class InterviewQuestion
    {
        // Message contents sent to the user.
        [JsonProperty("message")]
        public string message;

        // The type of question.
        [JsonConverter(typeof(StringEnumConverter))]
        [JsonProperty("type")]
        public QuestionType type;

        // Colour of the message embed.
        [JsonProperty("color")]
        public string color;

        // The ID of this message where the bot asked this question,
        // populated after it has been sent.
        [JsonProperty("message-id")]
        public ulong messageID;

        // Used as label for this question in the post-interview summary.
        [JsonProperty("summary-field")]
        public string summaryField;

        // The user's response to the question.
        [JsonProperty("answer")]
        public string answer;

        // The ID of the user's answer message, populated after it has been received.
        [JsonProperty("answer-id")]
        public ulong answerID;

        // Possible questions to ask next, or DONE/FAIL type in order to finish interview.
        [JsonProperty("paths")]
        public Dictionary<string, InterviewQuestion> paths;
    }

    // This class is identical to the one above and just exists as a hack to get JSON validation when
    // new entries are entered but not when read from database in order to be more lenient with old interviews.
    // I might do this in a more proper way at some point.
    public class ValidatedInterviewQuestion
    {
        // Message contents sent to the user.
        [JsonProperty("message", Required = Required.Always)]
        public string message;

        // The type of question.
        [JsonConverter(typeof(StringEnumConverter))]
        [JsonProperty("type", Required = Required.Always)]
        public QuestionType type;

        // Colour of the message embed.
        [JsonProperty("color", Required = Required.Always)]
        public string color;

        // The ID of this message where the bot asked this question,
        // populated after it has been sent.
        [JsonProperty("message-id", Required = Required.Default)]
        public ulong messageID;

        // Used as label for this question in the post-interview summary.
        [JsonProperty("summary-field", Required = Required.Default)]
        public string summaryField;

        // The user's response to the question.
        [JsonProperty("answer", Required = Required.Default)]
        public string answer;

        // The ID of the user's answer message, populated after it has been received.
        [JsonProperty("answer-id", Required = Required.Default)]
        public ulong answerID;

        // Possible questions to ask next, or DONE/FAIL type in order to finish interview.
        [JsonProperty("paths", Required = Required.Always)]
        public Dictionary<string, ValidatedInterviewQuestion> paths;
    }

    private static Dictionary<ulong, InterviewQuestion> categoryInterviews = [];

    private static Dictionary<ulong, InterviewQuestion> activeInterviews = [];

    public static void ParseTemplates(JToken interviewConfig)
    {
        categoryInterviews = JsonConvert.DeserializeObject<Dictionary<ulong, InterviewQuestion>>(interviewConfig.ToString(), new JsonSerializerSettings
        {
            Error = delegate (object sender, ErrorEventArgs args)
            {
                Logger.Error("Exception occured when trying to read interview from database:\n" + args.ErrorContext.Error.Message);
                Logger.Debug("Detailed exception:", args.ErrorContext.Error);
                args.ErrorContext.Handled = true;
            }
        });
    }

    public static void LoadActiveInterviews()
    {
        activeInterviews = Database.GetAllInterviews();
    }

    public static void StartInterview(DiscordChannel channel)
    {
        if (channel.Parent == null)
        {
            return;
        }

        if (categoryInterviews.TryGetValue(channel.Parent.Id, out InterviewQuestion interview))
        {
            CreateQuestion(channel, interview);
            Database.SaveInterview(channel.Id, interview);
        }
    }

    public static void ProcessResponse(DiscordMessage message)
    {
        // TODO: Find if channel has open interview.
        // TODO: Find if message is replying to interview message.
        // TODO: Handle other interactions like button presses.
        // TODO: Find out where in the interview tree we are.
        // TODO: Handle FAIL event, cancelling the interview.
        // TODO: Handle DONE event, creating a summary.

        //Database.SaveInterview(channel.Id, interview);
    }

    private static async void CreateQuestion(DiscordChannel channel, InterviewQuestion question)
    {
        DiscordMessageBuilder msgBuilder = new DiscordMessageBuilder();
        DiscordEmbedBuilder embed = new DiscordEmbedBuilder()
        {
            Color = Utilities.StringToColor(question.color),
            Description = question.message
        };

        switch (question.type)
        {
            case QuestionType.BUTTONS:
                int nrOfButtons = 0;
                for (int nrOfButtonRows = 0; nrOfButtonRows < 5 && nrOfButtons < question.paths.Count; nrOfButtonRows++)
                {
                    List<DiscordButtonComponent> buttonRow = [];
                    for (; nrOfButtons < 5 * (nrOfButtonRows + 1) && nrOfButtons < question.paths.Count; nrOfButtons++)
                    {
                        buttonRow.Add(new DiscordButtonComponent(DiscordButtonStyle.Primary, "supportchild_interviewbutton " + nrOfButtons, question.paths.ToArray()[nrOfButtons].Key));
                    }
                    msgBuilder.AddComponents(buttonRow);
                }
                break;
            case QuestionType.SELECTOR:
                List<DiscordSelectComponent> selectionComponents = [];

                int selectionOptions = 0;
                for (int selectionBoxes = 0; selectionBoxes < 5 && selectionOptions < question.paths.Count; selectionBoxes++)
                {
                    List<DiscordSelectComponentOption> categoryOptions = [];
                    for (; selectionOptions < 25 * (selectionBoxes + 1) && selectionOptions < question.paths.Count; selectionOptions++)
                    {
                        categoryOptions.Add(new DiscordSelectComponentOption(question.paths.ToArray()[selectionOptions].Key, selectionOptions.ToString()));
                    }
                    selectionComponents.Add(new DiscordSelectComponent("supportchild_interviewselector " + selectionBoxes, "Select an option...", categoryOptions, false, 0, 1));
                }

                msgBuilder.AddComponents(selectionComponents);
                break;
            case QuestionType.TEXT_INPUT:
                embed.WithFooter("Reply to this message with your answer.");
                break;
            case QuestionType.DONE:
            case QuestionType.FAIL:
            default:
                break;
        }

        msgBuilder.AddEmbed(embed);
        DiscordMessage message = await channel.SendMessageAsync(msgBuilder);
        question.messageID = message.Id;
    }

    public static void CreateSummary()
    {

    }
}