using Arch.Core;
using HSchool.Ai;
using HSchool.Content;
using HSchool.People;

namespace HSchool.Simulation;

/// <summary>Condition captions live in the catalog. The client draws what it is told.</summary>
public static class ApparelCondition
{
    public static string BandId(BehaviorDef? rules, float condition)
    {
        var bands = rules?.ApparelConditionBands is { Count: > 0 } listed
            ? listed
            : BehaviorDef.DefaultConditionBands;
        ApparelConditionBand? best = null;
        foreach (var band in bands)
        {
            if (condition >= band.Min && (best is null || band.Min > best.Min))
            {
                best = band;
            }
        }

        return best?.Id ?? "ApparelConditionRags";
    }

    public static string Label(DefCatalog catalog, string locale, float condition) =>
        catalog.Text(locale, BandId(catalog.BehaviorRules, condition));
}

/// <summary>
/// Worn apparel loses condition on campus from game time, then morning issues a fresh copy
/// of anything too ragged to leave home in. Bag and locker are left alone.
/// </summary>
internal static class ApparelWear
{
    private static readonly QueryDescription Identities =
        new QueryDescription().WithAll<PersonIdentity, Presence>();

    public static bool Apply(School school, double gameMinutes, DateTime before)
    {
        var bandCrossed = Wear(school, gameMinutes);
        if (!CrossedDayStart(before, school.Clock.Time))
        {
            return bandCrossed;
        }

        school.ResetDayLog();
        if (school.Catalog is null)
        {
            return bandCrossed;
        }

        var morningChanged = MorningDress.Apply(school);
        var opinionsChanged = MorningOpinions.Apply(school);
        var ragsReplaced = SchoolDay.IsWorkday(school.Catalog, school.Clock.Time, school.SchoolWeekDays)
            && ReplaceRags(school);
        return bandCrossed | morningChanged | opinionsChanged | ragsReplaced;
    }

    internal static bool CrossedDayStart(DateTime before, DateTime after)
    {
        if (after <= before)
        {
            return false;
        }

        var cursor = DateTime.SpecifyKind(before.Date, DateTimeKind.Utc).Add(SchoolDay.DayStart.ToTimeSpan());
        if (before >= cursor)
        {
            cursor = cursor.AddDays(1);
        }

        return after >= cursor;
    }

    private static bool Wear(School school, double gameMinutes)
    {
        if (gameMinutes <= 0 || school.Roster is null || school.Catalog?.BehaviorRules is null)
        {
            return false;
        }

        var rate = school.Catalog.BehaviorRules.ApparelWearPerHour;
        if (rate <= 0)
        {
            return false;
        }

        var onCampus = OnCampusIds(school);
        if (onCampus.Count == 0)
        {
            return false;
        }

        var drop = (float)(rate * (gameMinutes / 60d));
        var crossed = false;
        foreach (var person in school.Roster.People)
        {
            if (!onCampus.Contains(person.Id))
            {
                continue;
            }

            crossed |= WearPerson(school.Catalog, person, drop);
        }

        return crossed;
    }

    private static bool WearPerson(DefCatalog catalog, Person person, float drop)
    {
        var crossed = false;
        for (var i = 0; i < person.Items.Count; i++)
        {
            var item = person.Items[i];
            if (!item.Location.Equals(ItemLocations.Worn, StringComparison.Ordinal)
                || !IsApparel(catalog, item.Def))
            {
                continue;
            }

            var next = Math.Clamp(item.Condition - drop, 0f, 1f);
            if (next == item.Condition)
            {
                continue;
            }

            if (ApparelCondition.BandId(catalog.BehaviorRules, item.Condition)
                != ApparelCondition.BandId(catalog.BehaviorRules, next))
            {
                crossed = true;
            }

            SetItem(person, i, item with { Condition = next });
        }

        return crossed;
    }

    private static bool ReplaceRags(School school)
    {
        if (school.Roster is null || school.Catalog?.BehaviorRules is null)
        {
            return false;
        }

        var onCampus = OnCampusIds(school);
        var threshold = school.Catalog.BehaviorRules.ApparelReplaceBelow;
        var replaced = false;
        foreach (var person in school.Roster.People)
        {
            if (onCampus.Contains(person.Id))
            {
                continue;
            }

            replaced |= ReplacePerson(school, person, threshold);
        }

        return replaced;
    }

    private static bool ReplacePerson(School school, Person person, float threshold)
    {
        var catalog = school.Catalog!;
        var replaced = false;
        for (var i = 0; i < person.Items.Count; i++)
        {
            var item = person.Items[i];
            if (!item.Location.Equals(ItemLocations.Worn, StringComparison.Ordinal)
                || item.Condition >= threshold
                || !IsApparel(catalog, item.Def))
            {
                continue;
            }

            var color = NearestColor(catalog, item.Def, item.Color);
            SetItem(person, i, item with { Condition = 1f, Color = color });
            school.AppendDayLog(new PersonLogEvent(
                person.Id,
                school.Clock.Time,
                PersonLogTypes.ApparelReplaced,
                item.Def));
            replaced = true;
        }

        return replaced;
    }

    private static HashSet<string> OnCampusIds(School school)
    {
        var ids = new HashSet<string>(StringComparer.Ordinal);
        var world = school.World;
        world.Query(in Identities, (ref PersonIdentity identity, ref Presence presence) =>
        {
            if (presence.IsOnCampus)
            {
                ids.Add(identity.Id);
            }
        });
        return ids;
    }

    private static bool IsApparel(DefCatalog catalog, string defName) =>
        catalog.Things.TryGetValue(defName, out var def) && !def.Abstract && def.Layers.Count > 0;

    private static string? NearestColor(DefCatalog catalog, string defName, string? current)
    {
        if (!catalog.Things.TryGetValue(defName, out var def) || def.Colors.Count == 0)
        {
            return current;
        }

        if (current is not null
            && def.Colors.Contains(current, StringComparer.Ordinal))
        {
            return current;
        }

        return def.Colors[0];
    }

    private static void SetItem(Person person, int index, InventoryItem item)
    {
        if (person.Items is IList<InventoryItem> list && !list.IsReadOnly)
        {
            list[index] = item;
            return;
        }

        throw new InvalidOperationException($"Cannot mutate items for {person.Id}.");
    }
}