namespace HSchool.Content;

internal static class PeopleDefValidator
{
    public static void Validate(DefCatalog catalog)
    {
        foreach (var body in catalog.BodyAttributes.Values)
        {
            ValidateBody(body);
        }

        foreach (var skill in catalog.Skills.Values)
        {
            ValidateSkill(skill, catalog);
        }

        foreach (var trait in catalog.Traits.Values)
        {
            ValidateTrait(trait, catalog);
        }

        foreach (var need in catalog.Needs.Values)
        {
            ValidateNeed(need);
        }

        foreach (var names in catalog.NameSets.Values)
        {
            ValidateNameSet(names, catalog);
        }

        foreach (var subject in catalog.Subjects.Values)
        {
            ValidateSubject(subject, catalog);
        }

        foreach (var staffing in catalog.Staffing.Values)
        {
            ValidateStaffing(staffing);
        }

        foreach (var frame in catalog.DayFrames.Values)
        {
            ValidateDayFrame(frame);
        }

        foreach (var holiday in catalog.Holidays.Values)
        {
            ValidateHoliday(holiday);
        }

        foreach (var action in catalog.Actions.Values)
        {
            ValidateAction(action, catalog);
        }

        foreach (var behavior in catalog.Behavior.Values)
        {
            ValidateBehavior(behavior);
        }

        if (catalog.Staffing.Values.Count(def => !def.Abstract) > 1)
        {
            throw new ContentLoadException("A catalog may only have one concrete StaffingDef.");
        }

        if (catalog.DayFrames.Values.Count(def => !def.Abstract) > 1)
        {
            throw new ContentLoadException("A catalog may only have one concrete DayFrameDef.");
        }

        if (catalog.Behavior.Values.Count(def => !def.Abstract) > 1)
        {
            throw new ContentLoadException("A catalog may only have one concrete BehaviorDef.");
        }

        RequireBuildInputs(catalog);
    }

    /// <summary>
    /// The derived build reads these two by name. A pack without them would leave every person
    /// on the fallback height and weight, and the whole build column would read "Average".
    /// </summary>
    private static void RequireBuildInputs(DefCatalog catalog)
    {
        if (catalog.BodyAttributes.Count == 0)
        {
            return;
        }

        foreach (var required in new[] { BodyBuilds.HeightAttribute, BodyBuilds.WeightAttribute })
        {
            if (!catalog.BodyAttributes.TryGetValue(required, out var def) || def.Abstract)
            {
                throw new ContentLoadException(
                    $"BodyAttributeDef '{required}' is required: the derived build is computed from it.");
            }

            if (def.Kind != BodyAttributeKind.Number)
            {
                throw new ContentLoadException(
                    $"BodyAttributeDef '{required}' must be a number: the derived build is computed from it.");
            }
        }
    }

    private static void ValidateBody(BodyAttributeDef def)
    {
        if (def.DefName.Equals(BodyBuilds.Attribute, StringComparison.Ordinal))
        {
            throw new ContentLoadException($"BodyAttributeDef '{def.DefName}' is reserved for the derived build.");
        }

        switch (def.Kind)
        {
            case BodyAttributeKind.Number:
                if (def.Distributions.Count == 0)
                {
                    throw new ContentLoadException($"BodyAttributeDef '{def.DefName}' of kind number needs at least one distribution.");
                }

                foreach (var row in def.Distributions)
                {
                    RequireSex(row.Sex, def.DefName);
                    RequireAgeWindow(row.AgeMin, row.AgeMax, def.DefName);
                    if (row.Distribution.StdDev < 0)
                    {
                        throw new ContentLoadException($"BodyAttributeDef '{def.DefName}' has a negative stdDev.");
                    }

                    RequireRange(row.Range, $"BodyAttributeDef '{def.DefName}'");
                }

                break;

            case BodyAttributeKind.Choice:
                if (def.Options.Count == 0)
                {
                    throw new ContentLoadException($"BodyAttributeDef '{def.DefName}' of kind choice needs at least one option.");
                }

                var values = new HashSet<string>(StringComparer.Ordinal);
                foreach (var option in def.Options)
                {
                    if (string.IsNullOrWhiteSpace(option.Value) || !values.Add(option.Value))
                    {
                        throw new ContentLoadException($"BodyAttributeDef '{def.DefName}' has a missing or duplicate option.");
                    }

                    if (option.Weight < 1)
                    {
                        throw new ContentLoadException($"BodyAttributeDef '{def.DefName}' option '{option.Value}' needs a positive weight.");
                    }

                    RequireSex(option.Sex, def.DefName);
                    RequireAgeWindow(option.AgeMin, option.AgeMax, def.DefName);
                }

                break;

            default:
                throw new ContentLoadException($"BodyAttributeDef '{def.DefName}' has unknown kind '{def.Kind}'.");
        }
    }

    private static void ValidateSkill(SkillDef skill, DefCatalog catalog)
    {
        RequireRange(skill.Range, $"SkillDef '{skill.DefName}'");
        if (skill.Distribution is { StdDev: < 0 })
        {
            throw new ContentLoadException($"SkillDef '{skill.DefName}' has a negative stdDev.");
        }

        if (skill.AdultChance is < 0 or > 1)
        {
            throw new ContentLoadException($"SkillDef '{skill.DefName}' adultChance must be 0–1.");
        }

        foreach (var limit in skill.BodyLimits)
        {
            if (string.IsNullOrWhiteSpace(limit.Attribute))
            {
                throw new ContentLoadException($"SkillDef '{skill.DefName}' bodyLimits entry is missing attribute.");
            }

            if (limit.Min is { } min && limit.Max is { } max && min > max)
            {
                throw new ContentLoadException($"SkillDef '{skill.DefName}' bodyLimits min is above max.");
            }

            if (limit.Attribute.Equals(BodyBuilds.Attribute, StringComparison.Ordinal))
            {
                if (string.IsNullOrWhiteSpace(limit.Value) || !BodyBuilds.IsKnown(limit.Value))
                {
                    throw new ContentLoadException($"SkillDef '{skill.DefName}' bodyLimits references unknown build '{limit.Value}'.");
                }

                continue;
            }

            if (!catalog.BodyAttributes.TryGetValue(limit.Attribute, out var body))
            {
                throw new ContentLoadException($"SkillDef '{skill.DefName}' bodyLimits references unknown attribute '{limit.Attribute}'.");
            }

            if (body.Kind != BodyAttributeKind.Choice)
            {
                throw new ContentLoadException($"SkillDef '{skill.DefName}' bodyLimits attribute '{limit.Attribute}' is not categorical.");
            }

            if (string.IsNullOrWhiteSpace(limit.Value)
                || !body.Options.Any(option => option.Value.Equals(limit.Value, StringComparison.Ordinal)))
            {
                throw new ContentLoadException($"SkillDef '{skill.DefName}' bodyLimits references unknown value '{limit.Value}' of '{limit.Attribute}'.");
            }
        }
    }

    private static void ValidateTrait(TraitDef trait, DefCatalog catalog)
    {
        if (trait.Weight < 1)
        {
            throw new ContentLoadException($"TraitDef '{trait.DefName}' weight must be at least 1.");
        }

        RequireRange(trait.Age, $"TraitDef '{trait.DefName}'");

        foreach (var role in trait.Roles)
        {
            if (!PersonRoles.IsKnown(role))
            {
                throw new ContentLoadException($"TraitDef '{trait.DefName}' has unknown role '{role}'.");
            }
        }

        foreach (var other in trait.Incompatible)
        {
            if (!catalog.Traits.ContainsKey(other))
            {
                throw new ContentLoadException($"TraitDef '{trait.DefName}' is incompatible with unknown TraitDef '{other}'.");
            }
        }

        foreach (var modifier in trait.SkillModifiers)
        {
            if (!catalog.Skills.ContainsKey(modifier.Skill))
            {
                throw new ContentLoadException($"TraitDef '{trait.DefName}' skill modifier references unknown SkillDef '{modifier.Skill}'.");
            }
        }
    }

    private static void ValidateNeed(NeedDef need)
    {
        if (need.Min > need.Max)
        {
            throw new ContentLoadException($"NeedDef '{need.DefName}' min is above max.");
        }

        if (need.Initial < need.Min || need.Initial > need.Max)
        {
            throw new ContentLoadException($"NeedDef '{need.DefName}' initial is outside min–max.");
        }

        if (need.DecayPerHour < 0)
        {
            throw new ContentLoadException($"NeedDef '{need.DefName}' decayPerHour cannot be negative.");
        }
    }

    private static void ValidateSubject(SubjectDef subject, DefCatalog catalog)
    {
        if (subject.HoursPerWeek < 0)
        {
            throw new ContentLoadException($"SubjectDef '{subject.DefName}' hoursPerWeek cannot be negative.");
        }

        if (subject.Grades.Min < 1 || subject.Grades.Max > 11 || subject.Grades.Min > subject.Grades.Max)
        {
            throw new ContentLoadException($"SubjectDef '{subject.DefName}' grades must be 1–11 with min ≤ max.");
        }

        if (subject.Skills.Count == 0)
        {
            throw new ContentLoadException($"SubjectDef '{subject.DefName}' needs at least one skill.");
        }

        var seen = new HashSet<string>(StringComparer.Ordinal);
        foreach (var share in subject.Skills)
        {
            if (string.IsNullOrWhiteSpace(share.Skill) || !seen.Add(share.Skill))
            {
                throw new ContentLoadException($"SubjectDef '{subject.DefName}' has a missing or duplicate skill.");
            }

            if (!catalog.Skills.TryGetValue(share.Skill, out var skill) || skill.Abstract)
            {
                throw new ContentLoadException($"SubjectDef '{subject.DefName}' references unknown SkillDef '{share.Skill}'.");
            }

            if (share.Share < 0)
            {
                throw new ContentLoadException($"SubjectDef '{subject.DefName}' skill '{share.Skill}' share cannot be negative.");
            }
        }

        if (string.IsNullOrWhiteSpace(subject.Room))
        {
            return;
        }

        if (!catalog.Rooms.TryGetValue(subject.Room, out var room) || room.Abstract)
        {
            throw new ContentLoadException($"SubjectDef '{subject.DefName}' references unknown RoomDef '{subject.Room}'.");
        }
    }

    private static void ValidateStaffing(StaffingDef staffing)
    {
        if (staffing.Abstract)
        {
            return;
        }

        if (staffing.PoolSize < 1 || staffing.PoolSize > 64)
        {
            throw new ContentLoadException($"StaffingDef '{staffing.DefName}' poolSize must be 1–64.");
        }

        if (staffing.StayChance <= 0f || staffing.StayChance >= 1f)
        {
            throw new ContentLoadException($"StaffingDef '{staffing.DefName}' stayChance must be between 0 and 1 exclusive.");
        }

        if (staffing.ParentChance < 0f || staffing.ParentChance > 1f)
        {
            throw new ContentLoadException($"StaffingDef '{staffing.DefName}' parentChance must be 0–1.");
        }

        if (staffing.HourlyWageBase < 0f || staffing.HourlyWagePerSkill < 0f)
        {
            throw new ContentLoadException($"StaffingDef '{staffing.DefName}' wage scale cannot be negative.");
        }

        if (staffing.BaseWeeklyHours <= 0f || staffing.WeeksPerMonth <= 0f)
        {
            throw new ContentLoadException($"StaffingDef '{staffing.DefName}' monthly hours must be positive.");
        }

        if (staffing.MaxWeeklyHours < staffing.BaseWeeklyHours)
        {
            throw new ContentLoadException(
                $"StaffingDef '{staffing.DefName}' maxWeeklyHours must be at least baseWeeklyHours: "
                + "nobody can be paid for a full rate they are not allowed to work.");
        }
    }

    private static void ValidateDayFrame(DayFrameDef frame)
    {
        if (frame.Abstract)
        {
            return;
        }

        if (!SchoolDay.TryParseTime(frame.FirstLesson, out _))
        {
            throw new ContentLoadException($"DayFrameDef '{frame.DefName}' firstLesson '{frame.FirstLesson}' is not a time.");
        }

        if (frame.LessonCount is < 1 or > 12)
        {
            throw new ContentLoadException($"DayFrameDef '{frame.DefName}' lessonCount must be 1–12.");
        }

        if (frame.LessonMinutes is < 1 or > 180)
        {
            throw new ContentLoadException($"DayFrameDef '{frame.DefName}' lessonMinutes must be 1–180.");
        }

        if (frame.BreakMinutes is < 0 or > 60)
        {
            throw new ContentLoadException($"DayFrameDef '{frame.DefName}' breakMinutes must be 0–60.");
        }

        if (frame.LongBreakMinutes is < 0 or > 120)
        {
            throw new ContentLoadException($"DayFrameDef '{frame.DefName}' longBreakMinutes must be 0–120.");
        }

        if (frame.LongBreakAfter is < 0 || frame.LongBreakAfter >= frame.LessonCount)
        {
            throw new ContentLoadException($"DayFrameDef '{frame.DefName}' longBreakAfter must be 0 or a lesson before the last.");
        }

        var fed = new HashSet<int>();
        foreach (var sitting in frame.LunchBreaks)
        {
            if (sitting.AfterLesson < 1 || sitting.AfterLesson >= frame.LessonCount)
            {
                throw new ContentLoadException(
                    $"DayFrameDef '{frame.DefName}' has a lunch break after lesson {sitting.AfterLesson}; it must be a lesson before the last.");
            }

            if (sitting.GradeMin < 1 || sitting.GradeMax < sitting.GradeMin)
            {
                throw new ContentLoadException(
                    $"DayFrameDef '{frame.DefName}' has a lunch break with grades {sitting.GradeMin}–{sitting.GradeMax}.");
            }

            for (var year = sitting.GradeMin; year <= sitting.GradeMax; year++)
            {
                if (!fed.Add(year))
                {
                    throw new ContentLoadException(
                        $"DayFrameDef '{frame.DefName}' feeds grade {year} at two lunch breaks.");
                }
            }
        }
    }

    private static void ValidateAction(ActionDef action, DefCatalog catalog)
    {
        if (action.Abstract)
        {
            return;
        }

        if (string.IsNullOrWhiteSpace(action.Room))
        {
            throw new ContentLoadException($"ActionDef '{action.DefName}' needs a room.");
        }

        var roomKnown = catalog.Rooms.TryGetValue(action.Room, out var room) && !room.Abstract;
        var territoryKnown = catalog.Territories.TryGetValue(action.Room, out var territory) && !territory.Abstract;
        if (!roomKnown && !territoryKnown)
        {
            throw new ContentLoadException($"ActionDef '{action.DefName}' references unknown room '{action.Room}'.");
        }

        if (action.Minutes <= 0)
        {
            throw new ContentLoadException($"ActionDef '{action.DefName}' minutes must be positive.");
        }

        if (action.Weight < 0)
        {
            throw new ContentLoadException($"ActionDef '{action.DefName}' weight cannot be negative.");
        }

        if (!string.IsNullOrWhiteSpace(action.Thing))
        {
            if (!catalog.Things.TryGetValue(action.Thing, out var thing) || thing.Abstract)
            {
                throw new ContentLoadException($"ActionDef '{action.DefName}' references unknown ThingDef '{action.Thing}'.");
            }
        }

        if (string.IsNullOrWhiteSpace(action.Need))
        {
            if (action.NeedGain != 0)
            {
                throw new ContentLoadException($"ActionDef '{action.DefName}' has needGain without a need.");
            }
        }
        else if (!catalog.Needs.TryGetValue(action.Need, out var need) || need.Abstract)
        {
            throw new ContentLoadException($"ActionDef '{action.DefName}' references unknown NeedDef '{action.Need}'.");
        }

        foreach (var role in action.Roles)
        {
            if (!PersonRoles.IsKnown(role))
            {
                throw new ContentLoadException($"ActionDef '{action.DefName}' has unknown role '{role}'.");
            }
        }
    }

    private static void ValidateBehavior(BehaviorDef behavior)
    {
        if (behavior.Abstract)
        {
            return;
        }

        if (behavior.NeedThreshold < 0f || behavior.NeedThreshold > 1f)
        {
            throw new ContentLoadException($"BehaviorDef '{behavior.DefName}' needThreshold must be 0–1.");
        }

        if (behavior.LessonSkillPerHour < 0f)
        {
            throw new ContentLoadException($"BehaviorDef '{behavior.DefName}' lessonSkillPerHour cannot be negative.");
        }

        if (behavior.SwitchMargin < 0f)
        {
            throw new ContentLoadException($"BehaviorDef '{behavior.DefName}' switchMargin cannot be negative.");
        }

        if (behavior.CommuteSlackMin < 0 || behavior.CommuteSlackMax < behavior.CommuteSlackMin)
        {
            throw new ContentLoadException(
                $"BehaviorDef '{behavior.DefName}' commute slack must be a non-negative range with min ≤ max.");
        }
    }

    private static void ValidateHoliday(HolidayDef holiday)
    {
        if (holiday.Abstract)
        {
            return;
        }

        ValidateMonthDay(holiday.Start, holiday.DefName, "start");
        ValidateMonthDay(holiday.End, holiday.DefName, "end");
    }

    private static void ValidateMonthDay(MonthDay stamp, string defName, string field)
    {
        if (stamp.Month is < 1 or > 12)
        {
            throw new ContentLoadException($"HolidayDef '{defName}' {field} month must be 1–12.");
        }

        var days = DateTime.DaysInMonth(2000, stamp.Month);
        if (stamp.Day < 1 || stamp.Day > days)
        {
            throw new ContentLoadException($"HolidayDef '{defName}' {field} day is not valid for that month.");
        }
    }

    private static void ValidateNameSet(NameSetDef names, DefCatalog catalog)
    {
        if (!NameGrammar.IsKnownPatronymic(names.PatronymicRule))
        {
            throw new ContentLoadException($"NameSetDef '{names.DefName}' has unknown patronymicRule '{names.PatronymicRule}'.");
        }

        foreach (var native in names.Spoken)
        {
            if (!catalog.Skills.TryGetValue(native, out var language) || language.Abstract)
            {
                throw new ContentLoadException($"NameSetDef '{names.DefName}' native language '{native}' is not a SkillDef.");
            }
        }

        if (names.RelatedLanguageChance is < 0 or > 1)
        {
            throw new ContentLoadException($"NameSetDef '{names.DefName}' relatedLanguageChance must be 0–1.");
        }

        if (names.RelatedLanguageStdDev < 0)
        {
            throw new ContentLoadException($"NameSetDef '{names.DefName}' relatedLanguageStdDev must not be negative.");
        }

        if (names.RelatedLanguageMean < 0)
        {
            throw new ContentLoadException($"NameSetDef '{names.DefName}' relatedLanguageMean must not be negative.");
        }

        if (names.RelatedLanguageMax < 0)
        {
            throw new ContentLoadException($"NameSetDef '{names.DefName}' relatedLanguageMax must not be negative.");
        }

        if (!NameGrammar.IsKnownGiven(names.DefaultGivenDeclension))
        {
            throw new ContentLoadException($"NameSetDef '{names.DefName}' has unknown defaultGivenDeclension.");
        }

        if (!NameGrammar.IsKnownSurname(names.DefaultSurnameDeclension))
        {
            throw new ContentLoadException($"NameSetDef '{names.DefName}' has unknown defaultSurnameDeclension.");
        }

        if (names.MaleGiven.Count == 0 || names.FemaleGiven.Count == 0 || names.Surnames.Count == 0)
        {
            throw new ContentLoadException($"NameSetDef '{names.DefName}' needs male names, female names and surnames.");
        }

        foreach (var given in names.MaleGiven.Concat(names.FemaleGiven))
        {
            if (string.IsNullOrWhiteSpace(given.Form))
            {
                throw new ContentLoadException($"NameSetDef '{names.DefName}' has an empty given name.");
            }

            if (given.Cases is null)
            {
                var model = string.IsNullOrWhiteSpace(given.Declension)
                    ? names.DefaultGivenDeclension
                    : given.Declension;
                if (!NameGrammar.IsKnownGiven(model))
                {
                    throw new ContentLoadException($"NameSetDef '{names.DefName}' given '{given.Form}' has unknown declension '{model}'.");
                }
            }
        }

        foreach (var surname in names.Surnames)
        {
            if (string.IsNullOrWhiteSpace(surname.Male) || string.IsNullOrWhiteSpace(surname.Female))
            {
                throw new ContentLoadException($"NameSetDef '{names.DefName}' has a surname missing a gendered form.");
            }

            if (surname.MaleCases is null && surname.FemaleCases is null)
            {
                var model = string.IsNullOrWhiteSpace(surname.Declension)
                    ? names.DefaultSurnameDeclension
                    : surname.Declension;
                if (!NameGrammar.IsKnownSurname(model))
                {
                    throw new ContentLoadException($"NameSetDef '{names.DefName}' surname '{surname.Male}' has unknown declension '{model}'.");
                }
            }
        }
    }

    private static void RequireSex(string? sex, string defName)
    {
        if (sex is null)
        {
            return;
        }

        if (!sex.Equals("male", StringComparison.OrdinalIgnoreCase)
            && !sex.Equals("female", StringComparison.OrdinalIgnoreCase))
        {
            throw new ContentLoadException($"Def '{defName}' has unknown sex '{sex}'.");
        }
    }

    private static void RequireAgeWindow(int? min, int? max, string defName)
    {
        if (min is { } lo && max is { } hi && lo > hi)
        {
            throw new ContentLoadException($"Def '{defName}' has ageMin above ageMax.");
        }
    }

    private static void RequireRange(IntRange? range, string where)
    {
        if (range is { } value && value.Min > value.Max)
        {
            throw new ContentLoadException($"{where} range min is above max.");
        }
    }
}