using System.Reflection;
using UnityEngine;
using Wizard;
using Wizard.Battle;
using Wizard.Battle.Phase;
using Wizard.Battle.Recovery;
using Wizard.Battle.Replay;
using Wizard.Battle.Resource;
using Wizard.Battle.View.Vfx;
using Wizard.BattleMgr;

namespace SVSim.BattleEngine.Tests
{
    // Initializes the global engine state a headless battle assumes exists. In the real client this
    // is populated from /load/index at login; here we author the minimum the resolution path reads.
    public static class HeadlessEngineEnv
    {
        // Simplest zero-skill vanilla follower in cards.json: neutral (clan 0), cost 1, 1/2, no skill.
        public const int FollowerId = 100011010;

        // M3 next-hardest deterministic card: a fixed-damage spell. 900124030 is an ELF (clan 1, matches
        // PlayerClassId) cost-3 spell whose sole skill is `when_play` `damage=3` to `card_type=class`
        // (the enemy leader) — auto-targeted (no select_count), no RNG. Deterministic burn to the face.
        public const int SpellId = 900124030;

        // M4 next-hardest deterministic card: a when_play SELF-BUFF follower. 103111050 is an ELF
        // (clan 1) cost-1 1/1 whose sole non-evo skill is `when_play` `powerup` `add_offense=1&add_life=1`
        // with skill_target `character=me&target=self` — it buffs ITSELF, so no target selection (the
        // fanfare auto-resolves). Fixed +1/+1 => a deterministic stat-delta oracle. The skill is gated on
        // `play_count>2`; the headless harness seeds that via the public AddCurrentTrunPlayCount (see the
        // oracle test). Base 1/1 -> 2/2 after the fanfare.
        public const int BuffFollowerId = 103111050;
        public const int BuffAddOffense = 1;
        public const int BuffAddLife = 1;

        // M5 next-hardest deterministic card: a when_play SUMMON_TOKEN spell. 800134010 is an ELF
        // (clan 1) cost-1 spell whose sole skill is `when_play` `summon_token=100011020` with
        // `skill_target=none` and an UNGATED condition (`character=me`, trivially the caster): it
        // summons exactly ONE neutral 2/2 follower TOKEN onto the caster's board — no target
        // selection, no RNG (Skill_summon_token's random branch is `num >= 0 && !IsForecast`, and
        // this option carries no `random_count`, so num=-1 => the deterministic literal-id path).
        // The new oracle dimension over M2/M3/M4 is a BOARD-COUNT DELTA from a SKILL-CREATED card:
        // a token that was never in the hand/deck appears in play. This is also the first headless
        // exercise of the PUBLIC prefab card-creation path (CardCreatorBase.CreateCard,
        // createNullView:false, via BattlePlayerBase.CreateNextIndexCard) — class-card construction
        // hits `default: return null` and the M2-M4 hand cards used the private null-view seam, so
        // the view-building creation path is genuinely new here.
        public const int TokenSpellId = 800134010;
        public const int SummonedTokenId = 100011020; // neutral 2/2 follower token
        public const int SummonedTokenAtk = 2;
        public const int SummonedTokenLife = 2;

        // M6 next milestone: the first card requiring TARGET SELECTION — exercises the selectedCards
        // path of ActionProcessor.PlayCard (dormant through M2-M5, all of which played
        // selectedCards: null). 800134020 is an ELF (clan 1) cost-1 SPELL whose sole skill is
        // `when_play` `damage=5` to a SELECTED enemy follower
        // (skill_target=character=op&target=inplay&card_type=unit&select_count=1), ungated
        // (character=me), no RNG, no dynamic `{}` value. The new oracle dimension is SELECTION
        // ROUTING: with TWO followers on the enemy board and ONE passed as selectedCards, only the
        // selected follower takes the 5 damage and the un-selected one is untouched.
        public const int TargetSpellId = 800134020;
        public const int TargetSpellDamage = 5;

        // Two zero-skill vanilla NEUTRAL followers placed on the ENEMY board. Both have life > the
        // 5 damage so they SURVIVE — this gives a differential life-delta oracle (selected -5,
        // un-selected -0) that reads the authoritative damage path M3 already proved, without
        // depending on follower death/board-removal timing (a separate, unproven mechanic). Distinct
        // base life (13 vs 7) so the two post-states can't coincidentally match.
        public const int SelectTargetFollowerId = 900041010;   // neutral 13/13
        public const int UnselectTargetFollowerId = 102011010; // neutral 6/7

        private static bool _done;

        public static void EnsureInitialized()
        {
            if (_done) return;
            // Wizard.Data.Load: static /load/index snapshot. The ctor's CreateBackgroundId reads
            // Data.Load.data._userTutorial (LoadDetail self-inits _userTutorial). Suppress VFX too.
            Wizard.Data.Load = new Load { data = new LoadDetail() };
            // CardParameter(CardCSVData) reads Data.Crossover.RestrictedCard for deck-limit calc;
            // an empty Crossover returns the default count (no restriction). Private setter -> reflect.
            typeof(Wizard.Data).GetProperty("Crossover",
                System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.Public)
                .SetValue(null, new Wizard.Crossover());
            BattleManagerBase.IsForecast = true;
            // CardMaster must be non-null before construction (the leader/class card looks up id 0).
            // Load the M2 vanilla follower + the M3 fixed-damage spell + the M4 self-buff follower +
            // the M5 summon-token spell AND the token it summons so each oracle can create + look up
            // real stats. The summoned token id must be present: Skill_summon_token resolves it
            // through CardMaster.GetCardParameterFromId during creation.
            HeadlessCardMaster.Load(FollowerId, SpellId, BuffFollowerId, TokenSpellId, SummonedTokenId,
                TargetSpellId, SelectTargetFollowerId, UnselectTargetFollowerId);
            // Master reference data (class-character list) for leader/class card resolution.
            HeadlessMasterData.Install();
            // Player/enemy leaders (chara ids must map to a ClassCharacterMasterData in Master).
            // Set the backing fields directly: the public SetPlayerCharaId() also pulls MyRotation/
            // AvatarBattle info (more null statics) which the resolution path doesn't need (the
            // TryGet* accessors are null-tolerant).
            var dm = GameMgr.GetIns().GetDataMgr();
            SetField(dm, "_playerCharaId", HeadlessMasterData.PlayerCharaId);
            SetField(dm, "_enemyCharaId", HeadlessMasterData.EnemyCharaId);
            _done = true;
        }

        // Seed each leader's starting life on a freshly-constructed mgr. The engine does this in
        // BattleManagerBase.SetupInitialGameState -> InitializeClassLife (InitBaseMaxLife per leader),
        // but the full SetupInitialGameState also cascades into rotation/avatar/turn-panel UI init
        // that is irrelevant (and hostile) to a headless resolution test, so apply just the
        // InitializeClassLife subset. Without this a leader's BaseMaxLife defaults to 0 — which reads
        // as already-dead/game-over and silently blocks any card play (the M2 follower oracle never
        // noticed because it only asserted leader life *unchanged*, and 0 == 0).
        public const int DefaultLeaderLife = 20;

        public static void InitLeaderLife(BattleManagerBase mgr, int life = DefaultLeaderLife)
        {
            ((ClassBattleCardBase)mgr.BattlePlayer.Class).InitBaseMaxLife(life);
            ((ClassBattleCardBase)mgr.BattleEnemy.Class).InitBaseMaxLife(life);
        }

        // The PUBLIC prefab card-creation path (CardCreatorBase.CreateCard, createNullView:false) —
        // used by anything the engine creates INTERNALLY (summons, token-draws, etc.), as opposed to
        // the test's direct private null-view seam for hand cards — clones card-template prefabs held
        // on BattleManagerBase.SBattleLoad. The real async battle load (CoLoad) builds these; the bare
        // `new SingleBattleMgr(...)` construction path leaves SBattleLoad null (the M2 NRE was here).
        // Seed it with non-null no-op CardTemplates: their `.gameObject` is a lazy shim no-op, and the
        // shim's CloneObjectToParent + self-consistent object graph carry the rest. Nothing here
        // computes game state — the token's authoritative stats come from CardCSVData, not the view.
        public static void InitCardTemplates(BattleManagerBase mgr)
        {
            mgr.SBattleLoad = new SBattleLoad
            {
                UnitCardTemplate = new CardTemplate(),
                SpellCardTemplate = new CardTemplate(),
                FieldCardTemplate = new CardTemplate(),
            };
            // The created card's transform is positioned/parented under the battle's 3D scene-graph
            // containers (CardCreatorBase.CreateCardTypeBuildInfo reads ins.CardHolder/ECardHolder/
            // PCardPlace/Battle3DContainer). The real battle load instantiates these; seed non-null
            // no-op GameObjects so the positioning resolves (no-op transforms; nothing rendered).
            mgr.Battle3DContainer = new GameObject();
            mgr.CardHolder = new GameObject();
            mgr.ECardHolder = new GameObject();
            mgr.PCardPlace = new GameObject();
            mgr.ChoiceCardHolder = new GameObject();
            mgr.EvolveCardHolder = new GameObject();
        }

        // The shared headless card-creation primitive. CardCreatorBase.CreateCardWithoutResources is
        // the engine's own null-view creation path (CreateBase -> new *BattleCard(buildInfo).Setup(
        // createNullView:true)); it's private, so reflect it rather than reimplement the 14-arg
        // BuildInfo wiring. The public CardCreatorBase.CreateCard goes through prefab cloning.
        //
        // The engine's CreateCard also calls owner.SetupCardEvent(card); the raw
        // CreateCardWithoutResources seam skips it, so we fold it in here. SetupCardEvent wires the
        // per-card play events (BattlePlayerBase.cs:1452): for a SPELL/amulet it attaches
        // OnPlay -> RemoveSpellCardFromHand and OnFinishWhenPlaySkill -> AddSpellCardToCemetery, which
        // are how a non-follower leaves the hand at all (a follower's hand->field move is intrinsic to
        // SetUpInplay, not event-driven). For a follower SetupCardEvent only attaches an OnEvolve hook
        // that never fires on a vanilla play, so folding it in is a no-op there — making this a single
        // primitive both follower and non-follower oracles can share.
        public static BattleCardBase CreateHeadlessHandCard(int cardId, int index, bool isPlayer, BattleManagerBase mgr)
        {
            var io = mgr.CreatePlayerInnerOptionsBuilder();
            var m = typeof(CardCreatorBase).GetMethod("CreateCardWithoutResources",
                BindingFlags.NonPublic | BindingFlags.Static);
            var card = (BattleCardBase)m.Invoke(null, new object[] { cardId, index, isPlayer, mgr, io });
            BattlePlayerBase owner = isPlayer ? (BattlePlayerBase)mgr.BattlePlayer : mgr.BattleEnemy;
            owner.SetupCardEvent(card);
            return card;
        }

        // Put a follower DIRECTLY onto a player's board headless (vs as a side-effect of PlayCard),
        // for setting up a target board state. Create it through the shared null-view seam, then drive
        // the engine's own hand->field move: HandCardToField requires the card to be in HandCardList,
        // then AddInplayCards it + removes it from hand (BattlePlayerBase.cs:2568). For a vanilla
        // follower the OnAddPlayCard/StopBattleHandCard/OnSummonAfter events it fires are no-ops (no
        // fanfare), so the follower lands on the board at its CardCSVData base stats. M2 proved the
        // hand->field placement path resolves headless.
        public static BattleCardBase PutFollowerInPlay(BattleManagerBase mgr, int cardId, int index, bool isPlayer)
        {
            var card = CreateHeadlessHandCard(cardId, index, isPlayer, mgr);
            BattlePlayerBase owner = isPlayer ? (BattlePlayerBase)mgr.BattlePlayer : mgr.BattleEnemy;
            owner.HandCardList.Add(card);
            owner.HandCardToField(card);
            return card;
        }

        private static void SetField(object obj, string name, object value)
        {
            var f = obj.GetType().GetField(name,
                System.Reflection.BindingFlags.Instance |
                System.Reflection.BindingFlags.NonPublic |
                System.Reflection.BindingFlags.Public);
            if (f == null) throw new System.InvalidOperationException(
                $"{obj.GetType().Name} has no field '{name}'");
            f.SetValue(obj, value);
        }
    }

    // Test-side replica of the engine's own StandardBattleMgrContentsCreator (the practice/solo
    // init path: GameMgr.cs:244 `new SingleBattleMgr(new StandardBattleMgrContentsCreator(null, null))`).
    // Authored here (not copied) so we control the seed deterministically; uses the real engine
    // managers verbatim. The real StandardBattleMgrContentsCreator + SingleBattlePhaseCreator were
    // cut from the M1 copy set (entry-point constructors), so we reproduce them minimally.
    public sealed class HeadlessContentsCreator : IBattleMgrContentsCreator
    {
        public int RandomSeed => 12345; // fixed; vanilla follower has no RNG so value is irrelevant

        // No-op managers (vs the practice path's file-backed SingleBattleRecoveryRecordManager):
        // the ctor's FirstRecoverySetting/FirstReplaySetting dereference these, and recovery/replay
        // recording is irrelevant to the M2 oracle, so use the engine's own null implementations.
        public IRecoveryManager RecoveryManager { get; } = new NullRecoveryManager();
        public IRecoveryRecordManager RecoveryRecordManager { get; } = new NullRecoveryRecordManager();
        public IReplayRecordManager ReplayRecordManager { get; } = new NullReplayRecordManager();

        public IBattleResourceMgr CreateResourceMgr() => new BattleResourceMgr();
        public VfxMgr CreateVfxMgr() => new VfxMgr();
        public IPhaseCreator CreatePhaseCreator(BattleManagerBase battleMgr) =>
            new HeadlessPhaseCreator(battleMgr);
    }

    // Equivalent of the engine's SingleBattlePhaseCreator: inherits PhaseCreatorBase wholesale.
    public sealed class HeadlessPhaseCreator : PhaseCreatorBase
    {
        public HeadlessPhaseCreator(BattleManagerBase battleMgr) : base(battleMgr) { }
    }
}