#include "core.h"
#include "handmade.h"
#include "sdl_handmade.h"

#include "handmade_intrinsics.h"
#include <string.h> /* memset */

static void GameOutputSound(game_state *GameState,
                            game_sound_output_buffer *SoundBuffer,
                            S32 ToneHz)
{
    /*
    S16 ToneVolume, *SampleOut;
    S32 WavePeriod, SampleIndex;

    ToneVolume = 0;
    WavePeriod = SoundBuffer->SamplesPerSecond / ToneHz;

    SampleOut = SoundBuffer->Samples;

    for(SampleIndex = 0;
        SampleIndex < SoundBuffer->SampleCount;
        SampleIndex++)
    {
        F32 SineValue;
        S16 SampleValue;

        SineValue = sinf(GameState->tSine);
        SampleValue = (S16)(SineValue * ToneVolume);
        *SampleOut++ = SampleValue;
        *SampleOut++ = SampleValue;

        GameState->tSine += 2.0f * (F32)PI * 1.0f / (F32)WavePeriod;
        if(GameState->tSine > 2.0f*(F32)PI) {
            GameState->tSine -= 2.0f*(F32)PI;
        }
    }
    */
}

static void ClearBackground(game_offscreen_buffer *Buffer)
{
    S32 Width, Height, X;

    Width = Buffer->Width;
    Height = Buffer->Height;

    for(X = 0; X < Width * Height; X++) {
        U32 *Pixel = &((U32 *)Buffer->Memory)[X];
        *Pixel = 0xFFFFFF;
    }
}

static void DrawRectangle(game_offscreen_buffer *Buffer,
                          F32 RealMinX, F32 RealMinY,
                          F32 RealMaxX, F32 RealMaxY,
                          F32 R, F32 G, F32 B)
{
    S32 MinX = RoundF32toS32(RealMinX);
    S32 MinY = RoundF32toS32(RealMinY);
    S32 MaxX = RoundF32toS32(RealMaxX);
    S32 MaxY = RoundF32toS32(RealMaxY);

    S32 Width = Buffer->Width;
    S32 Height = Buffer->Height;

    U8 *Row;
    S32 Y, X;
    U32 Color;

    if(MinX < 0)
        MinX = 0;
    if(MinY < 0)
        MinY = 0;

    if(MaxX > Width)
        MaxX = Width;
    if(MaxY > Height)
        MaxY = Height;

    Color = (U32)((RoundF32toS32(R * 255.0f) << 16) |
                  (RoundF32toS32(G * 255.0f) <<  8) |
                  (RoundF32toS32(B * 255.0f) <<  0));

    Row = ((U8 *)Buffer->Memory + MinX*Buffer->BytesPerPixel +
          MinY*Buffer->Pitch);
    for(Y = MinY; Y < MaxY; Y++) {
        U32 *Pixel = (U32 *)Row;
        for(X = MinX; X < MaxX; X++) {
            *(U32 *)Pixel = Color;
            Pixel++;
        }
        Row += Buffer->Pitch;
    }
}

static tile_map *GetTileMap(world *World, S32 TileMapX, S32 TileMapY)
{
    tile_map *TileMap = NULL;

    if((TileMapX >= 0) && (TileMapX < World->TileMapCountX) &&
       (TileMapY >= 0) && (TileMapY < World->TileMapCountY))
    {
        TileMap =
            &World->TileMaps[TileMapY*World->TileMapCountX + TileMapX];
    }

    return TileMap;
}

static U32 GetTileValueUnchecked(world *World, tile_map *TileMap, S32 TileX, S32 TileY)
{
    U32 TileMapValue;

    ASSERT(TileMap);
    ASSERT((TileX >= 0) && (TileX < World->CountX) &&
           (TileY >= 0) && (TileY < World->CountY));

    TileMapValue = TileMap->Tiles[TileY*World->CountX + TileX];
    return TileMapValue;
}

static B32 IsTileMapPointEmpty(world *World, tile_map *TileMap,
                               S32 TestTileX, S32 TestTileY)
{
    B32 Empty = FALSE;

    if(TileMap) {
        if((TestTileX >= 0) && (TestTileX < World->CountX) &&
           (TestTileY >= 0) && (TestTileY < World->CountY))
        {
            U32 TileMapValue =
                GetTileValueUnchecked(World, TileMap, TestTileX, TestTileY);
            Empty = (TileMapValue == 0);
        }
    }

    return Empty;
}

static cannonical_position GetCannonicalPosition(world *World,
                                                 raw_position Pos)
{
    cannonical_position Result;
    F32 X, Y;

    Result.TileMapX = Pos.TileMapX;
    Result.TileMapY = Pos.TileMapY;

    X = Pos.X - World->UpperLeftX;
    Y = Pos.Y - World->UpperLeftY;
    Result.TileX = FloorF32toS32(X / World->TileWidth);
    Result.TileY = FloorF32toS32(Y / World->TileHeight);

    Result.X = X - Result.TileX*World->TileWidth;
    Result.Y = Y - Result.TileY*World->TileHeight;

    ASSERT(Result.X >= 0);
    ASSERT(Result.Y >= 0);
    ASSERT(Result.X < World->TileWidth);
    ASSERT(Result.Y < World->TileHeight);

    if(Result.TileX < 0) {
        Result.TileX = World->CountX + Result.TileX;
        Result.TileMapX--;
    }
    if(Result.TileY < 0) {
        Result.TileY = World->CountY + Result.TileY;
        Result.TileMapY--;
    }
    if(Result.TileX >= World->CountX) {
        Result.TileX = Result.TileX - World->CountX;
        Result.TileMapX++;
    }
    if(Result.TileY >= World->CountY) {
        Result.TileY = Result.TileY - World->CountY;
        Result.TileMapY++;
    }

    return Result;
}

static B32 IsWorldPointEmpty(world *World, raw_position TestPos)
{
    B32 Empty = FALSE;

    tile_map *TileMap;

    cannonical_position CanPos = GetCannonicalPosition(World, TestPos);
    TileMap = GetTileMap(World, CanPos.TileMapX, CanPos.TileMapY);
    Empty = IsTileMapPointEmpty(World, TileMap, CanPos.TileX, CanPos.TileY);

    return Empty;
}

void UpdateAndRender(thread_context *Thread, game_memory *Memory,
                     game_input *Input, game_offscreen_buffer *Buffer,
                     game_sound_output_buffer *SoundBuffer)
{
#define TILEMAP_COUNT_X 17
#define TILEMAP_COUNT_Y  9

    game_state *GameState;
    U32 ControllerIndex;
    S32 Row, Column;

    U32 Tiles00[TILEMAP_COUNT_Y][TILEMAP_COUNT_X] = {
        {1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  1},
        {1, 1, 0, 0,  0, 1, 0, 0,  0, 0, 0, 0,  0, 1, 0, 0,  1},
        {1, 1, 0, 0,  0, 0, 0, 0,  1, 0, 0, 0,  0, 0, 1, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  1, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 1, 0, 0,  1, 0, 0, 0,  0, 0, 1, 0,  0},
        {1, 1, 0, 0,  0, 1, 0, 0,  1, 0, 0, 0,  0, 1, 0, 0,  1},
        {1, 0, 0, 0,  0, 1, 0, 0,  1, 0, 0, 0,  1, 0, 0, 0,  1},
        {1, 1, 1, 1,  1, 0, 0, 0,  0, 0, 0, 0,  0, 1, 0, 0,  1},
        {1, 1, 1, 1,  1, 1, 1, 1,  0, 1, 1, 1,  1, 1, 1, 1,  1},
    };
    U32 Tiles01[TILEMAP_COUNT_Y][TILEMAP_COUNT_X] = {
        {1, 1, 1, 1,  1, 1, 1, 1,  0, 1, 1, 1,  1, 1, 1, 1,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  1},
    };
    U32 Tiles10[TILEMAP_COUNT_Y][TILEMAP_COUNT_X] = {
        {1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 1, 1, 1,  1, 1, 1, 1,  0, 1, 1, 1,  1, 1, 1, 1,  1},
    };
    U32 Tiles11[TILEMAP_COUNT_Y][TILEMAP_COUNT_X] = {
        {1, 1, 1, 1,  1, 1, 1, 1,  0, 1, 1, 1,  1, 1, 1, 1,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  1},
        {1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  1},
    };

    F32 PlayerR, PlayerG, PlayerB, PlayerWidth, PlayerHeight,
        PlayerLeft, PlayerTop;

    tile_map TileMaps[2][2];
    tile_map *TileMap;
    world World;

    ASSERT((&Input->Controllers[0].u.buttons.Terminator -
            &Input->Controllers[0].u.Buttons[0]) ==
                              ARRAY_SIZE(Input->Controllers[0].u.Buttons));
    ASSERT(sizeof(game_state) <= Memory->PermanentStorageSize);

    TileMaps[0][0].Tiles = (U32 *)Tiles00;
    TileMaps[0][1].Tiles = (U32 *)Tiles10;
    TileMaps[1][0].Tiles = (U32 *)Tiles01;
    TileMaps[1][1].Tiles = (U32 *)Tiles11;

    memset(&World, 0, sizeof(World));
    World.TileMapCountX = 2;
    World.TileMapCountY = 2;
    World.CountX = TILEMAP_COUNT_X;
    World.CountY = TILEMAP_COUNT_Y;
    World.UpperLeftX =  0.0f;
    World.UpperLeftY =  0.0f;
    World.TileWidth  = 57.0f;
    World.TileHeight = 57.0f;
    World.TileMaps   = (tile_map *)TileMaps;

    PlayerWidth = 0.75f * World.TileWidth;
    PlayerHeight = World.TileHeight;

    GameState = (game_state *)Memory->PermanentStorage;
    if(!Memory->IsInitialized) {
        GameState->PlayerX = 200.0f;
        GameState->PlayerY = 200.0f;

        Memory->IsInitialized = TRUE;
    }

    TileMap = GetTileMap(&World, GameState->PlayerTileMapX,
                                 GameState->PlayerTileMapY);
    ASSERT(TileMap);

    for(ControllerIndex = 0;
        ControllerIndex < ARRAY_SIZE(Input->Controllers);
        ControllerIndex++)
    {
        game_controller_input *Controller =
            GetController(Input, ControllerIndex);
        if(Controller->IsAnalog) {
        } else {
            F32 dPlayerX = 0.0f;
            F32 dPlayerY = 0.0f;

            F32 NewPlayerX, NewPlayerY;

            raw_position PlayerPos, PlayerLeft, PlayerRight;

            if(Controller->u.buttons.MoveUp.EndedDown) {
                dPlayerY = -1.0f;
            }
            if(Controller->u.buttons.MoveDown.EndedDown) {
                dPlayerY = 1.0f;
            }
            if(Controller->u.buttons.MoveLeft.EndedDown) {
                dPlayerX = -1.0f;
            }
            if(Controller->u.buttons.MoveRight.EndedDown) {
                dPlayerX = 1.0f;
            }

            dPlayerX *= 200.0f;
            dPlayerY *= 200.0f;

            NewPlayerX = RoundF32toS32(GameState->PlayerX +
                                       Input->dtForFrame*dPlayerX);
            NewPlayerY = RoundF32toS32(GameState->PlayerY +
                                       Input->dtForFrame*dPlayerY);

            PlayerPos.TileMapX = GameState->PlayerTileMapX;
            PlayerPos.TileMapY = GameState->PlayerTileMapY;
            PlayerPos.X = NewPlayerX;
            PlayerPos.Y = NewPlayerY;

            PlayerLeft = PlayerPos;
            PlayerLeft.X -= 0.5f*PlayerWidth;

            PlayerRight = PlayerPos;
            PlayerRight.X += 0.5f*PlayerWidth;

            if(IsWorldPointEmpty(&World, PlayerPos) &&
               IsWorldPointEmpty(&World, PlayerLeft) &&
               IsWorldPointEmpty(&World, PlayerRight))
            {
                cannonical_position CanPos =
                    GetCannonicalPosition(&World, PlayerPos);

                GameState->PlayerTileMapX = CanPos.TileMapX;
                GameState->PlayerTileMapY = CanPos.TileMapY;
                GameState->PlayerX = World.UpperLeftX +
                    World.TileWidth*CanPos.TileX + CanPos.X;
                GameState->PlayerY = World.UpperLeftY +
                    World.TileHeight*CanPos.TileY + CanPos.Y;
            }
        }
    }

    DrawRectangle(Buffer, 0.0f, 0.0f,
                  (F32)(Buffer->Width), (F32)(Buffer->Height),
                  0.0f, 1.0f, 0.0f);

    for(Row = 0; Row < TILEMAP_COUNT_Y; Row++) {
        for(Column = 0; Column < TILEMAP_COUNT_X; Column++) {
            F32 MinX, MinY, MaxX, MaxY;
            U32 TileID = GetTileValueUnchecked(&World, TileMap, Column, Row);
            F32 Gray = 0.5f;
            if(TileID) {
                Gray = 1.0f;
            }
            MinX = World.UpperLeftX + (F32)(Column) * World.TileWidth;
            MinY = World.UpperLeftY + (F32)(Row) * World.TileHeight;
            MaxX = MinX + World.TileWidth;
            MaxY = MinY + World.TileHeight;
            DrawRectangle(Buffer, MinX, MinY, MaxX, MaxY, Gray, Gray, Gray);
        }
    }

    PlayerR = 1.0f;
    PlayerG = 0.0f;
    PlayerB = 0.0f;
    PlayerLeft = GameState->PlayerX - 0.5f*PlayerWidth;
    PlayerTop = GameState->PlayerY - PlayerHeight;
    DrawRectangle(Buffer,
                  PlayerLeft, PlayerTop,
                  PlayerLeft + PlayerWidth, PlayerTop + PlayerHeight,
                  PlayerR, PlayerG, PlayerB);

    DrawRectangle(Buffer,
                  (F32)(Input->MouseX) - 15.0f, (F32)(Input->MouseY) - 15.0f,
                  (F32)(Input->MouseX) + 5.0f, (F32)(Input->MouseY) + 5.0f,
                  1.0f, 0.5f, 0.0f);

    GameOutputSound(GameState, SoundBuffer, 400);
}

/*
static void RenderWeirdGradient(game_offscreen_buffer *Buffer, S32 XOffset,
                                S32 YOffset)
{
    S32 Width, Height, Y;
    U8 *Row;

    Width = Buffer->Width;
    Height = Buffer->Height;

    Row = (U8 *)Buffer->Memory;
    for(Y = 0; Y < Height; Y++) {
        U32 *Pixel = (U32 *)Row;
        S32 X;

        Pixel = (U32 *)Row;
        for(X = 0; X < Width; X++) {
            U8 Blue, Green;

            Blue = (U8)(X + XOffset);
            Green = (U8)(Y + YOffset);

            *Pixel = (Green << 8) | Blue;
            Pixel++;
        }
        Row += Buffer->Pitch;
    }
}
*/