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

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

#include "handmade_tile.h"
#include "handmade_tile.cpp"

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 void InitializeArena(memory_arena *Arena, U64 Size, U8 *Base)
{
    Arena->Size = Size;
    Arena->Base = Base;
    Arena->Used = 0;
}

#define PUSH_STRUCT(Arena, type) (type *)PushSize_(Arena, sizeof(type))
#define PUSH_ARRAY(Arena, Count, type) (type *)PushSize_(Arena, (Count)*sizeof(type))
static void *PushSize_(memory_arena *Arena, U64 Size)
{
    void *Result;

    ASSERT((Arena->Used + Size) <= Arena->Size);

    Result = (void *)(Arena->Base + Arena->Used);
    Arena->Used += Size;
    return Result;
}

void UpdateAndRender(thread_context *Thread, game_memory *Memory,
                     game_input *Input, game_offscreen_buffer *Buffer,
                     game_sound_output_buffer *SoundBuffer)
{
#define TILEMAP_COUNT_X 256
#define TILEMAP_COUNT_Y 256

    game_state *GameState;
    U32 ControllerIndex;

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

    world *World;
    tile_map *TileMap;

    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);

    PlayerHeight = 1.4f;
    PlayerWidth = 0.75f * PlayerHeight;

    GameState = (game_state *)Memory->PermanentStorage;
    if(!Memory->IsInitialized) {
        U32 TilesPerWidth, TilesPerHeight;
        U32 ScreenX, ScreenY;
        tile_map *TileMap;
        world *World;

        GameState->PlayerP.AbsTileX = 2;
        GameState->PlayerP.AbsTileY = 3;
        GameState->PlayerP.TileRelX = 5.0f;
        GameState->PlayerP.TileRelY = 5.0f;

        InitializeArena(&GameState->WorldArena,
                        Memory->PermanentStorageSize - sizeof(game_state),
                        (U8 *)Memory->PermanentStorage + sizeof(game_state));

        GameState->World = PUSH_STRUCT(&GameState->WorldArena, world);
        World = GameState->World;
        World->TileMap = PUSH_STRUCT(&GameState->WorldArena, tile_map);

        TileMap = World->TileMap;

        TileMap->ChunkShift = 8;
        TileMap->ChunkMask = (1 << TileMap->ChunkShift) - 1;
        TileMap->ChunkDim = 256;

        TileMap->TileChunkCountX = 4;
        TileMap->TileChunkCountY = 4;

        TileMap->TileChunks =
            PUSH_ARRAY(&GameState->WorldArena,
                       TileMap->TileChunkCountX*TileMap->TileChunkCountX,
                       tile_chunk);

        {
            U32 X, Y;
            for(Y = 0; Y < TileMap->TileChunkCountY; Y++) {
                for(X = 0; X < TileMap->TileChunkCountX; X++) {
                    TileMap->TileChunks[Y*TileMap->TileChunkCountX + X].Tiles =
                        PUSH_ARRAY(&GameState->WorldArena,
                                   TileMap->ChunkDim*TileMap->ChunkDim,
                                   U32);
                }
            }
        }

        TileMap->TileSideInMeters = 1.4f;
        TileMap->TileSideInPixels = 60;
        TileMap->MetersToPixels =
            (F32)TileMap->TileSideInPixels / TileMap->TileSideInMeters;

        TilesPerWidth = 17;
        TilesPerHeight =  9;
        for(ScreenY = 0; ScreenY < 32; ScreenY++) {
            for(ScreenX = 0; ScreenX < 32; ScreenX++) {
                U32 TileX, TileY;
                for(TileY = 0; TileY < TilesPerWidth; TileY++) {
                    for(TileX = 0; TileX < TilesPerWidth; TileX++) {
                        U32 AbsTileX = ScreenX * TilesPerWidth + TileX;
                        U32 AbsTileY = ScreenY * TilesPerHeight + TileY;

                        SetTileValue(&GameState->WorldArena,
                                     World->TileMap,
                                     AbsTileX, AbsTileY,
                                     (TileX == TileY) && (TileY % 2) ? 1 : 0);
                    }
                }
            }
        }

        Memory->IsInitialized = TRUE;
    }

    World = GameState->World;
    TileMap = World->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;

            tile_map_position NewPlayerP, 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;
            }

            {
                F32 PlayerSpeed = 2.0f;

                if(Controller->u.buttons.ActionUp.EndedDown)
                    PlayerSpeed = 10.0f;

                dPlayerX *= PlayerSpeed;
                dPlayerY *= PlayerSpeed;
            }

            NewPlayerP = GameState->PlayerP;
            NewPlayerP.TileRelX += Input->dtForFrame*dPlayerX;
            NewPlayerP.TileRelY += Input->dtForFrame*dPlayerY;
            NewPlayerP = RecannonicalizePosition(TileMap, NewPlayerP);

            PlayerLeft = NewPlayerP;
            PlayerLeft.TileRelX -= 0.5f*PlayerWidth;
            PlayerLeft = RecannonicalizePosition(TileMap, PlayerLeft);

            PlayerRight = NewPlayerP;
            PlayerRight.TileRelX += 0.5f*PlayerWidth;
            PlayerRight = RecannonicalizePosition(TileMap, PlayerRight);

            if(IsTileMapPointEmpty(TileMap, NewPlayerP) &&
               IsTileMapPointEmpty(TileMap, PlayerLeft) &&
               IsTileMapPointEmpty(TileMap, PlayerRight))
            {
                GameState->PlayerP = NewPlayerP;
            }
        }
    }

    ScreenCenterX = 0.5f * (F32)Buffer->Width;
    ScreenCenterY = 0.5f * (F32)Buffer->Height;

    DrawRectangle(Buffer, 0.0f, 0.0f,
                  (F32)Buffer->Width, (F32)Buffer->Height,
                  0.0f, 1.0f, 0.0f);
    {
        S32 RelRow, RelColumn;
        for(RelRow = -10; RelRow < 10; RelRow++) {
            for(RelColumn = -20; RelColumn < 20; RelColumn++) {
                U32 Column = GameState->PlayerP.AbsTileX + RelColumn;
                U32 Row    = GameState->PlayerP.AbsTileY + RelRow;

                U32 TileID = GetTileValue(TileMap, Column, Row);
                F32 Gray = 0.5f;

                if(TileID) {
                    Gray = 1.0f;
                }

                if((Column == GameState->PlayerP.AbsTileX) &&
                   (Row == GameState->PlayerP.AbsTileY))
                {
                    Gray = 0.0f;
                }

                {
                    F32 CenterX, CenterY, MinX, MinY, MaxX, MaxY;

                    CenterX = ScreenCenterX -
                           TileMap->MetersToPixels*GameState->PlayerP.TileRelX +
                           (F32)RelColumn * (F32)TileMap->TileSideInPixels;
                    CenterY = ScreenCenterY +
                           TileMap->MetersToPixels*GameState->PlayerP.TileRelY -
                           (F32)RelRow * (F32)TileMap->TileSideInPixels;
                    MinX = CenterX - 0.5f*(F32)TileMap->TileSideInPixels;
                    MinY = CenterY - 0.5f*(F32)TileMap->TileSideInPixels;
                    MaxX = CenterX + 0.5f*(F32)TileMap->TileSideInPixels;
                    MaxY = CenterY + 0.5f*(F32)TileMap->TileSideInPixels;
                    DrawRectangle(Buffer,
                                  MinX, MinY, MaxX, MaxY,
                                  Gray, Gray, Gray);
                }
            }
        }
    }

    PlayerR = 1.0f;
    PlayerG = 0.0f;
    PlayerB = 0.0f;
    PlayerLeft = ScreenCenterX - 0.5f* TileMap->MetersToPixels*PlayerWidth;
    PlayerTop = ScreenCenterY - TileMap->MetersToPixels*PlayerHeight;
    DrawRectangle(Buffer,
                  PlayerLeft, PlayerTop,
                  PlayerLeft + TileMap->MetersToPixels*PlayerWidth,
                  PlayerTop + TileMap->MetersToPixels*PlayerHeight,
                  PlayerR, PlayerG, PlayerB);

    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;
    }
}
*/