using System.Globalization;
using Arch.Core;
using HSchool.Content;

namespace HSchool.Simulation;

/// <summary>
/// Log row types the person card pages. Captions for morning issue are ready even while phase 34
/// is the one that appends that row.
/// </summary>
public static class PersonLogTypes
{
    public const string ActionStarted = "action-started";
    public const string ActionEnded = "action-ended";
    public const string TalkEnded = "talk-ended";
    public const string ApparelReplaced = "apparel-replaced";
    public const string ApparelChanged = "apparel-changed";
    public const string LessonNoTeacher = "lesson-no-teacher";
    public const string LessonCold = "lesson-cold";
}

/// <summary>
/// One thing that happened to a person today. Stored on the school worker, not in <c>people.json</c>.
/// The day boundary is six in the morning — the same hour skip lands on.
/// </summary>
public sealed record PersonLogEvent(string PersonId, DateTime Time, string Type, string? ThingDef)
{
    public string Caption(DefCatalog catalog, string locale)
    {
        ArgumentNullException.ThrowIfNull(catalog);
        if (ThingDef is null)
        {
            return Type;
        }

        if (Type.Equals(PersonLogTypes.ApparelReplaced, StringComparison.Ordinal))
        {
            var name = catalog.Things.TryGetValue(ThingDef, out var def)
                ? catalog.Label(locale, def)
                : ThingDef;
            return string.Format(CultureInfo.InvariantCulture, catalog.Text(locale, "ApparelReplaced"), name);
        }

        if (Type.Equals(PersonLogTypes.ApparelChanged, StringComparison.Ordinal))
        {
            var name = catalog.Things.TryGetValue(ThingDef, out var def)
                ? catalog.Label(locale, def)
                : ThingDef;
            return string.Format(CultureInfo.InvariantCulture, catalog.Text(locale, "ApparelChanged"), name);
        }

        if (Type.Equals(PersonLogTypes.ActionStarted, StringComparison.Ordinal)
            || Type.Equals(PersonLogTypes.ActionEnded, StringComparison.Ordinal))
        {
            var name = catalog.Actions.TryGetValue(ThingDef, out var action)
                ? catalog.Label(locale, action)
                : ThingDef;
            var key = Type.Equals(PersonLogTypes.ActionStarted, StringComparison.Ordinal)
                ? "ActionStarted"
                : "ActionEnded";
            return string.Format(CultureInfo.InvariantCulture, catalog.Text(locale, key), name);
        }

        if (Type.Equals(PersonLogTypes.LessonNoTeacher, StringComparison.Ordinal)
            || Type.Equals(PersonLogTypes.LessonCold, StringComparison.Ordinal))
        {
            var name = catalog.Subjects.TryGetValue(ThingDef, out var subject)
                ? catalog.Label(locale, subject)
                : ThingDef;
            var key = Type.Equals(PersonLogTypes.LessonCold, StringComparison.Ordinal)
                ? "LessonCold"
                : "LessonNoTeacher";
            return string.Format(CultureInfo.InvariantCulture, catalog.Text(locale, key), name);
        }

        if (Type.Equals(PersonLogTypes.TalkEnded, StringComparison.Ordinal))
        {
            var topic = catalog.Topics.TryGetValue(ThingDef ?? "", out var def)
                ? catalog.Label(locale, def)
                : ThingDef ?? Type;
            return string.Format(CultureInfo.InvariantCulture, catalog.Text(locale, "TalkEnded"), topic);
        }

        return Type;
    }
}

public readonly record struct PersonLogQuery(string? Search, bool Descending, int Page, int PageSize);

public sealed record PersonLogPage(int Total, int Page, int PageSize, IReadOnlyList<PersonLogRow> Entries);

public sealed record PersonLogRow(DateTime Time, string Type, string Label, string? ThingDef);

/// <summary>Filters, sorts and pages today's log for one person. Does not touch a World.</summary>
public static class PersonLogBrowser
{
    public const int DefaultPageSize = 20;

    public const int MaxPageSize = 100;

    public static PersonLogPage Apply(
        IReadOnlyList<PersonLogEvent> log,
        string personId,
        PersonLogQuery query,
        DefCatalog? catalog,
        string locale)
    {
        ArgumentNullException.ThrowIfNull(log);
        ArgumentException.ThrowIfNullOrWhiteSpace(personId);

        var page = Math.Max(1, query.Page);
        var pageSize = Math.Clamp(query.PageSize, 1, MaxPageSize);
        var search = string.IsNullOrWhiteSpace(query.Search) ? null : query.Search.Trim();
        var rows = new List<PersonLogRow>();
        foreach (var row in log)
        {
            if (!row.PersonId.Equals(personId, StringComparison.Ordinal))
            {
                continue;
            }

            var label = catalog is null ? row.Type : row.Caption(catalog, locale);
            if (search is not null
                && !label.Contains(search, StringComparison.OrdinalIgnoreCase)
                && !row.Type.Contains(search, StringComparison.OrdinalIgnoreCase)
                && (row.ThingDef is null || !row.ThingDef.Contains(search, StringComparison.OrdinalIgnoreCase)))
            {
                continue;
            }

            rows.Add(new PersonLogRow(row.Time, row.Type, label, row.ThingDef));
        }

        rows.Sort((left, right) =>
        {
            var byTime = left.Time.CompareTo(right.Time);
            return query.Descending ? -byTime : byTime;
        });

        var skip = (page - 1) * pageSize;
        var slice = skip >= rows.Count ? Array.Empty<PersonLogRow>() : rows.Skip(skip).Take(pageSize).ToArray();
        return new PersonLogPage(rows.Count, page, pageSize, slice);
    }
}

/// <summary>Records action start/end and clears yesterday at six in the morning.</summary>
internal static class PersonDayLog
{
    private static readonly QueryDescription IdentityAndActivity =
        new QueryDescription().WithAll<PersonIdentity, PersonActivity>();

    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;
    }

    internal static void Sync(School school)
    {
        var world = school.World;
        var seen = new HashSet<string>(StringComparer.Ordinal);
        var query = IdentityAndActivity;
        world.Query(in query, (ref PersonIdentity identity, ref PersonActivity activity) =>
        {
            seen.Add(identity.Id);
            Record(school, identity.Id, activity.ActionId);
        });

        foreach (var id in school.LoggedActivity.Keys.ToArray())
        {
            if (!seen.Contains(id))
            {
                Record(school, id, current: null);
                school.LoggedActivity.Remove(id);
            }
        }
    }

    private static void Record(School school, string personId, string? current)
    {
        school.LoggedActivity.TryGetValue(personId, out var last);
        if (string.Equals(last, current, StringComparison.Ordinal))
        {
            school.LoggedActivity[personId] = current;
            return;
        }

        if (last is not null)
        {
            school.AppendDayLog(new PersonLogEvent(personId, school.Clock.Time, PersonLogTypes.ActionEnded, last));
        }

        if (current is not null)
        {
            school.AppendDayLog(new PersonLogEvent(personId, school.Clock.Time, PersonLogTypes.ActionStarted, current));
        }

        school.LoggedActivity[personId] = current;
    }
}