using System;
using System.Collections.Generic;
using System.Globalization;

namespace ytLive.Models;

/// <summary>Which of the eight facts the creator put on screen, and how each renders.
///
/// <para>Every tile is optional because the strip is an ego wall — the creator chooses the
/// billboard. Goal tiles carry their targets here so the rendering stays a pure function of the
/// state plus this selection.</para></summary>
public sealed class ScoreboardTiles
{
    /// <summary>Nothing enabled — the layer draws nothing.</summary>
    public static ScoreboardTiles None => new();

    /// <summary>The selection a new layer starts with: the six session facts, no channel polls
    /// (those need the Analytics scope).</summary>
    public static ScoreboardTiles Default => new()
    {
        SuperChats = true, NewMembers = true, Milestones = true,
        LastMember = true, LastSuperChat = true, LastGift = true,
    };

    public bool Subscribers { get; set; }
    public bool WatchHours { get; set; }
    public bool SuperChats { get; set; }
    public bool NewMembers { get; set; }
    public bool Milestones { get; set; }
    public bool LastMember { get; set; }
    public bool LastSuperChat { get; set; }
    public bool LastGift { get; set; }

    /// <summary>Goal targets for the two polled tiles; 0 means "no goal, show the raw number".</summary>
    public int SubscriberGoal { get; set; }
    public int WatchHourGoal { get; set; }

    /// <summary>Channel state fed by the polled side (subscribers, watch hours). Kept here so the
    /// strip is built from ONE source of truth: tallies + channel values + this selection.</summary>
    public int SubscriberCount { get; set; }
    public int WatchHoursValue { get; set; }

    /// <summary>Cache key: the selection alone. Values are folded in by the presenter's fingerprint,
    /// so this only needs to change when the ENABLED SET changes.</summary>
    public string CacheKey =>
        $"{Subscribers}{WatchHours}{SuperChats}{NewMembers}{Milestones}{LastMember}{LastSuperChat}{LastGift}" +
        $"{SubscriberGoal}{WatchHourGoal}";

    /// <summary>The strip's text, in reading order. Empty strings are dropped by the renderer.</summary>
    public IReadOnlyList<string> Build(ScoreboardState state)
    {
        var tiles = new List<string>(8);

        if (Subscribers)
            tiles.Add(SubscriberGoal > 0
                ? $"Subs {SubscriberCount:N0}/{SubscriberGoal:N0}"
                : $"Subs {SubscriberCount:N0}");

        if (WatchHours)
            // Analytics is a DAILY aggregate, so the tile must not imply live data.
            tiles.Add(WatchHourGoal > 0
                ? $"Hours {WatchHoursValue:N0}/{WatchHourGoal:N0} (as of {DateTime.Now:MMM d})"
                : $"Hours {WatchHoursValue:N0} (as of {DateTime.Now:MMM d})");

        if (SuperChats && state.SessionTotal.Total > 0)
            tiles.Add(state.HasMixedCurrencies
                ? $"SC {state.SessionTotal.Currency} {state.SessionTotal.Total:0.00} +{state.MoneyByCurrency.Count - 1}"
                : $"SC {state.SessionTotal.Currency} {state.SessionTotal.Total:0.00}");

        if (NewMembers && state.NewMembers > 0)
            tiles.Add($"Members +{state.NewMembers}");

        if (Milestones && state.MilestoneCount > 0)
            tiles.Add($"Milestones {state.MilestoneCount}");

        if (LastMember && !string.IsNullOrWhiteSpace(state.LastMemberName))
            tiles.Add($"Last member {state.LastMemberName}");

        if (LastSuperChat && !string.IsNullOrWhiteSpace(state.LastSuperChatDisplay))
            tiles.Add($"Last SC {state.LastSuperChatDisplay}");

        if (LastGift && !string.IsNullOrWhiteSpace(state.LastGifterName))
            tiles.Add($"Last gift {state.LastGifterName} ×{Math.Max(1, state.LastGiftCount)}");

        return tiles;
    }
}