(*
 * Hedgewars, a free turn based strategy game
 * Copyright (c) 2004-2011 Andrey Korotaev <unC0Rr@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 *)

{$INCLUDE "options.inc"}

unit uAI;
interface
uses uFloat;

procedure initModule;
procedure freeModule;

procedure ProcessBot;
procedure FreeActionsList;

implementation
uses uConsts, SDLh, uAIMisc, uAIAmmoTests, uAIActions,
     uAmmos, SysUtils{$IFDEF UNIX}{$IFNDEF ANDROID}, cthreads{$ENDIF}{$ENDIF}, uTypes,
     uVariables, uCommands, uUtils, uDebug;

var BestActions: TActions;
    CanUseAmmo: array [TAmmoType] of boolean;
    StopThinking: boolean;
    ThinkThread: PSDL_Thread = nil;
    hasThread: LongInt;

procedure FreeActionsList;
begin
AddFileLog('FreeActionsList called');
if hasThread <> 0 then
   begin
   AddFileLog('Waiting AI thread to finish');
   StopThinking:= true;
   repeat
     SDL_Delay(10)
   until hasThread = 0
   end;

with CurrentHedgehog^ do
     if Gear <> nil then
        if BotLevel <> 0 then
           StopMessages(Gear^.Message);

BestActions.Count:= 0;
BestActions.Pos:= 0
end;



const cBranchStackSize = 12;
type TStackEntry = record
                   WastedTicks: Longword;
                   MadeActions: TActions;
                   Hedgehog: TGear;
                   end;

var Stack: record
           Count: Longword;
           States: array[0..Pred(cBranchStackSize)] of TStackEntry;
           end;

function Push(Ticks: Longword; const Actions: TActions; const Me: TGear; Dir: integer): boolean;
var bRes: boolean;
begin
    bRes:= (Stack.Count < cBranchStackSize) and (Actions.Count < MAXACTIONS - 5);
    if bRes then
        with Stack.States[Stack.Count] do
            begin
            WastedTicks:= Ticks;
            MadeActions:= Actions;
            Hedgehog:= Me;
            Hedgehog.Message:= Dir;
            inc(Stack.Count)
            end;
    Push:= bRes
end;

procedure Pop(var Ticks: Longword; var Actions: TActions; var Me: TGear);
begin
    dec(Stack.Count);
    with Stack.States[Stack.Count] do
        begin
        Ticks:= WastedTicks;
        Actions:= MadeActions;
        Me:= Hedgehog
        end
end;



procedure TestAmmos(var Actions: TActions; Me: PGear; isMoved: boolean);
var BotLevel: Byte;
    ap: TAttackParams;
    Score, i: LongInt;
    a, aa: TAmmoType;
begin
BotLevel:= Me^.Hedgehog^.BotLevel;

for i:= 0 to Pred(Targets.Count) do
    if (Targets.ar[i].Score >= 0) and (not StopThinking) then
       begin
       with CurrentHedgehog^ do
            a:= CurAmmoType;
       aa:= a;
       SDL_delay(0);    //ThreadSwitch was only a hint
       
       repeat
        if (CanUseAmmo[a]) and
           ((not isMoved) or ((AmmoTests[a].flags and amtest_OnTurn) = 0)) then
           begin
{$HINTS OFF}
           Score:= AmmoTests[a].proc(Me, Targets.ar[i].Point, BotLevel, ap);
{$HINTS ON}
           if Actions.Score + Score > BestActions.Score then
            if (BestActions.Score < 0) or (Actions.Score + Score > BestActions.Score + Byte(BotLevel) * 2048) then
              begin
              BestActions:= Actions;
              inc(BestActions.Score, Score);
              BestActions.isWalkingToABetterPlace:= false;

              if (ap.Angle > 0) then AddAction(BestActions, aia_LookRight, 0, 200, 0, 0)
              else if (ap.Angle < 0) then AddAction(BestActions, aia_LookLeft, 0, 200, 0, 0);

              AddAction(BestActions, aia_Weapon, Longword(a), 300 + random(400), 0, 0);
              if (ap.Time <> 0) then AddAction(BestActions, aia_Timer, ap.Time div 1000, 400, 0, 0);
              if (Ammoz[a].Ammo.Propz and ammoprop_NoCrosshair) = 0 then
                 begin
                 ap.Angle:= LongInt(Me^.Angle) - Abs(ap.Angle);
                 if ap.Angle > 0 then
                    begin
                    AddAction(BestActions, aia_Up, aim_push, 300 + random(250), 0, 0);
                    AddAction(BestActions, aia_Up, aim_release, ap.Angle, 0, 0)
                    end else if ap.Angle < 0 then
                    begin
                    AddAction(BestActions, aia_Down, aim_push, 300 + random(250), 0, 0);
                    AddAction(BestActions, aia_Down, aim_release, -ap.Angle, 0, 0)
                    end
                 end;
              if (Ammoz[a].Ammo.Propz and ammoprop_NeedTarget) <> 0 then
                 begin
                 AddAction(BestActions, aia_Put, 0, 1, ap.AttackPutX, ap.AttackPutY)
                 end;
              if (Ammoz[a].Ammo.Propz and ammoprop_AttackingPut) = 0 then
                 begin
                 AddAction(BestActions, aia_attack, aim_push, 650 + random(300), 0, 0);
                 AddAction(BestActions, aia_attack, aim_release, ap.Power, 0, 0);
                 end;
              if ap.ExplR > 0 then
                 AddAction(BestActions, aia_AwareExpl, ap.ExplR, 10, ap.ExplX, ap.ExplY);
              end
           end;
        if a = High(TAmmoType) then a:= Low(TAmmoType)
                               else inc(a)
       until (a = aa) or
             (CurrentHedgehog^.MultiShootAttacks > 0) or // shooting same weapon
             StopThinking
       end
end;

procedure Walk(Me: PGear; var Actions: TActions);
const FallPixForBranching = cHHRadius * 2 + 8;
var
    ticks, maxticks, steps, tmp: Longword;
    BaseRate, BestRate, Rate: integer;
    GoInfo: TGoInfo;
    CanGo: boolean;
    AltMe: TGear;
    BotLevel: Byte;
    a: TAmmoType;
begin
ticks:= 0; // avoid compiler hint
Stack.Count:= 0;

for a:= Low(TAmmoType) to High(TAmmoType) do
    CanUseAmmo[a]:= Assigned(AmmoTests[a].proc) and HHHasAmmo(Me^.Hedgehog^, a);

BotLevel:= Me^.Hedgehog^.BotLevel;

tmp:= random(2) + 1;
Push(0, Actions, Me^, tmp);
Push(0, Actions, Me^, tmp xor 3);

if (Me^.State and gstAttacked) = 0 then maxticks:= Max(0, TurnTimeLeft - 5000 - LongWord(4000 * BotLevel))
                                   else maxticks:= TurnTimeLeft;

if (Me^.State and gstAttacked) = 0 then TestAmmos(Actions, Me, false);
BestRate:= RatePlace(Me);
BaseRate:= Max(BestRate, 0);

if (Ammoz[Me^.Hedgehog^.CurAmmoType].Ammo.Propz and ammoprop_NeedTarget) <> 0 then
    AddAction(Actions, aia_Weapon, Longword(amNothing), 100 + random(200), 0, 0);

while (Stack.Count > 0) and (not StopThinking) and (GameFlags and gfArtillery = 0) do
    begin
    Pop(ticks, Actions, Me^);

    AddAction(Actions, Me^.Message, aim_push, 250, 0, 0);
    if (Me^.Message and gmLeft) <> 0 then AddAction(Actions, aia_WaitXL, hwRound(Me^.X), 0, 0, 0)
                                      else AddAction(Actions, aia_WaitXR, hwRound(Me^.X), 0, 0, 0);
    steps:= 0;

    while (not StopThinking) do
       begin
{$HINTS OFF}
       CanGo:= HHGo(Me, @AltMe, GoInfo);
{$HINTS ON}
       inc(ticks, GoInfo.Ticks);
       if ticks > maxticks then break;

       if (BotLevel < 5) and (GoInfo.JumpType = jmpHJump) then // hjump support
          if Push(ticks, Actions, AltMe, Me^.Message) then
             with Stack.States[Pred(Stack.Count)] do
                  begin
                  if Me^.dX.isNegative then AddAction(MadeActions, aia_LookRight, 0, 200, 0, 0)
                                       else AddAction(MadeActions, aia_LookLeft, 0, 200, 0, 0);
                  AddAction(MadeActions, aia_HJump, 0, 305 + random(50), 0, 0);
                  AddAction(MadeActions, aia_HJump, 0, 350, 0, 0);
                  if Me^.dX.isNegative then AddAction(MadeActions, aia_LookLeft, 0, 200, 0, 0)
                                       else AddAction(MadeActions, aia_LookRight, 0, 200, 0, 0);
                  end;
       if (BotLevel < 3) and (GoInfo.JumpType = jmpLJump) then // ljump support
          if Push(ticks, Actions, AltMe, Me^.Message) then
             with Stack.States[Pred(Stack.Count)] do
                  AddAction(MadeActions, aia_LJump, 0, 305 + random(50), 0, 0);

       if not CanGo then break;
       inc(steps);
       Actions.actions[Pred(Actions.Count)].Param:= hwRound(Me^.X);
       Rate:= RatePlace(Me);
       if Rate > BestRate then
          begin
          BestActions:= Actions;
          BestActions.isWalkingToABetterPlace:= true;
          BestRate:= Rate;
          Me^.State:= Me^.State or gstAttacked // we have better place, go there and do not use ammo
          end
       else if Rate < BestRate then break;
       if ((Me^.State and gstAttacked) = 0)
           and ((steps mod 4) = 0) then TestAmmos(Actions, Me, true);
       if GoInfo.FallPix >= FallPixForBranching then
          Push(ticks, Actions, Me^, Me^.Message xor 3); // aia_Left xor 3 = aia_Right
       end;

    if BestRate > BaseRate then exit
    end
end;

function Think(Me: Pointer): ptrint;
var BackMe, WalkMe: TGear;
    StartTicks, currHedgehogIndex, itHedgehog, switchesNum, i: Longword;
    switchImmediatelyAvailable, switchAvailable: boolean;
    Actions: TActions;
begin
InterlockedIncrement(hasThread);
StartTicks:= GameTicks;
currHedgehogIndex:= CurrentTeam^.CurrHedgehog;
itHedgehog:= currHedgehogIndex;
switchesNum:= 0;

switchImmediatelyAvailable:= (CurAmmoGear <> nil) and (CurAmmoGear^.Kind = gtSwitcher);
switchAvailable:= HHHasAmmo(PGear(Me)^.Hedgehog^, amSwitch);

if (PGear(Me)^.State and gstAttacked) = 0 then
   if Targets.Count > 0 then
      begin
        // iterate over current team hedgehogs
        repeat
            WalkMe:= CurrentTeam^.Hedgehogs[itHedgehog].Gear^;

            Actions.Count:= 0;
            Actions.Pos:= 0;
            Actions.Score:= 0;
            if switchesNum > 0 then
                begin
                if not switchImmediatelyAvailable then
                    begin
                    // when AI has to use switcher, make it cost smth
                    Actions.Score:= -20000;
                    AddAction(Actions, aia_Weapon, Longword(amSwitch), 300 + random(200), 0, 0);                    
                    AddAction(Actions, aia_attack, aim_push, 300 + random(300), 0, 0);
                    AddAction(Actions, aia_attack, aim_release, 1, 0, 0);
                    end;
                for i:= 1 to switchesNum do
                    AddAction(Actions, aia_Switch, 0, 300 + random(200), 0, 0);
                end;
            Walk(@WalkMe, Actions);

            // find another hog in team
            repeat
                itHedgehog:= Succ(itHedgehog) mod CurrentTeam^.HedgehogsNumber;
            until (itHedgehog = currHedgehogIndex) or (CurrentTeam^.Hedgehogs[itHedgehog].Gear <> nil);

            inc(switchesNum);
        until (not (switchImmediatelyAvailable or switchAvailable))
            or StopThinking 
            or (itHedgehog = currHedgehogIndex)
            or BestActions.isWalkingToABetterPlace;

        if (StartTicks > GameTicks - 1500) and (not StopThinking) then SDL_Delay(1000);

        if (BestActions.Score < -1023) and (not BestActions.isWalkingToABetterPlace) then
            begin
            BestActions.Count:= 0;
            AddAction(BestActions, aia_Skip, 0, 250, 0, 0);
            end;

      end else
else begin
    BackMe:= PGear(Me)^;
    while (not StopThinking) and (BestActions.Count = 0) do
        begin
        FillBonuses(true);
        WalkMe:= BackMe;
        Actions.Count:= 0;
        Actions.Pos:= 0;
        Actions.Score:= 0;
        Walk(@WalkMe, Actions);
        if not StopThinking then SDL_Delay(100)
        end
    end;

PGear(Me)^.State:= PGear(Me)^.State and not gstHHThinking;
Think:= 0;
InterlockedDecrement(hasThread)
end;

procedure StartThink(Me: PGear);
begin
if ((Me^.State and (gstAttacking or gstHHJumping or gstMoving)) <> 0)
   or isInMultiShoot then exit;

//DeleteCI(Me); // this might break demo
Me^.State:= Me^.State or gstHHThinking;
Me^.Message:= 0;

BestActions.Count:= 0;
BestActions.Pos:= 0;
BestActions.Score:= Low(LongInt);
BestActions.isWalkingToABetterPlace:= false;

StopThinking:= false;
ThinkingHH:= Me;

FillTargets;
if Targets.Count = 0 then
   begin
   OutError('AI: no targets!?', false);
   exit
   end;

FillBonuses((Me^.State and gstAttacked) <> 0);
AddFileLog('Enter Think Thread');
{$IFDEF IPHONEOS}
//TODO: sdl_thread works on device but crashes in simulator, most likely because of outdated toolchain
BeginThread(@Think, Me, ThinkThread);
{$ELSE}
ThinkThread := SDL_CreateThread(@Think{$IFDEF SDL13}, nil{$ENDIF}, Me);
{$ENDIF}
AddFileLog('Thread started');
end;

procedure ProcessBot;
const StartTicks: Longword = 0;
      cStopThinkTime = 40;
begin
with CurrentHedgehog^ do
     if (Gear <> nil)
        and ((Gear^.State and gstHHDriven) <> 0)
        and (TurnTimeLeft < cHedgehogTurnTime - 50) then
        if ((Gear^.State and gstHHThinking) = 0) then
           if (BestActions.Pos >= BestActions.Count)
              and (TurnTimeLeft > cStopThinkTime) then
              begin
              if Gear^.Message <> 0 then
                 begin
                 StopMessages(Gear^.Message);
                 TryDo((Gear^.Message and gmAllStoppable) = 0, 'Engine bug: AI may break demos playing', true);
                 end;
              if Gear^.Message <> 0 then exit;
              StartThink(Gear);
              StartTicks:= GameTicks
              end else ProcessAction(BestActions, Gear)
        else if ((GameTicks - StartTicks) > cMaxAIThinkTime)
                or (TurnTimeLeft <= cStopThinkTime) then StopThinking:= true
end;

procedure initModule;
begin
    hasThread:= 0;
    ThinkThread:= ThinkThread;
end;

procedure freeModule;
begin

end;

end.