using HSchool.Content;
using HSchool.People;

namespace HSchool.Ai;

/// <summary>
/// Pure map / roster helpers for auto director summons. Queue state lives on the school worker.
/// </summary>
public static class DirectorSummons
{
    public const string HearingAction = "PrincipalHearing";

    public const string OfficeRoomDef = "PrincipalsOffice";

    public const string CorridorRoomDef = "Corridor";

    public static string? OfficeNodeId(MapLayout map)
    {
        ArgumentNullException.ThrowIfNull(map);
        return map.Rooms
            .Where(room => room.Def.Equals(OfficeRoomDef, StringComparison.Ordinal))
            .Select(room => room.Id)
            .OrderBy(id => id, StringComparer.Ordinal)
            .FirstOrDefault();
    }

    /// <summary>
    /// Corridor (or other neighbour) where the queue waits — never inside the office.
    /// Prefer a <see cref="CorridorRoomDef"/> link; tie-break by ordinal id.
    /// </summary>
    public static string? WaitNodeId(MapLayout map, string? officeNodeId = null)
    {
        ArgumentNullException.ThrowIfNull(map);
        officeNodeId ??= OfficeNodeId(map);
        if (officeNodeId is null)
        {
            return null;
        }

        string? bestCorridor = null;
        string? bestAny = null;
        foreach (var link in map.Links)
        {
            var other = OtherEnd(link, officeNodeId);
            if (other is null)
            {
                continue;
            }

            bestAny = PickOrdinal(bestAny, other);
            if (map.NodeDef(other) is { } def
                && def.Equals(CorridorRoomDef, StringComparison.Ordinal))
            {
                bestCorridor = PickOrdinal(bestCorridor, other);
            }
        }

        return bestCorridor ?? bestAny;
    }

    public static bool HasHiredPrincipal(Roster roster) =>
        roster.People.Any(person =>
            person.IsStaff
            && Staffing.PrincipalPosition.Equals(person.Position, StringComparison.Ordinal));

    public static string? PrincipalId(Roster roster) =>
        roster.People
            .Where(person =>
                person.IsStaff
                && Staffing.PrincipalPosition.Equals(person.Position, StringComparison.Ordinal))
            .Select(person => person.Id)
            .OrderBy(id => id, StringComparer.Ordinal)
            .FirstOrDefault();

    public static bool CanStart(Roster roster, MapLayout map) =>
        HasHiredPrincipal(roster) && OfficeNodeId(map) is not null && WaitNodeId(map) is not null;

    public static bool RollSummon(float chance, int seed) =>
        chance >= 1f || (chance > 0f && TalkCircles.Roll01(seed) < chance);

    private static string? OtherEnd(MapLink link, string nodeId)
    {
        if (link.A.Equals(nodeId, StringComparison.Ordinal))
        {
            return link.B;
        }

        if (link.B.Equals(nodeId, StringComparison.Ordinal))
        {
            return link.A;
        }

        return null;
    }

    private static string PickOrdinal(string? current, string candidate)
    {
        if (current is null)
        {
            return candidate;
        }

        return string.CompareOrdinal(candidate, current) < 0 ? candidate : current;
    }
}