/* date = April 26th 2023 5:12 pm */

#ifndef VN_PLATFORM_H
#define VN_PLATFORM_H

#include "vn_core.h"

// sixten: Services the platform provides to the application

struct platform_memory_block
{
    u8 *Base;
    u64 Size;
    
    u64 Used;
    platform_memory_block *ArenaPrev;
};

#define PLATFORM_ALLOCATE_MEMORY(name) platform_memory_block *name(u64 Size)
typedef PLATFORM_ALLOCATE_MEMORY(platform_allocate_memory);

#define PLATFORM_DEALLOCATE_MEMORY(name) b32 name(platform_memory_block *Block)
typedef PLATFORM_DEALLOCATE_MEMORY(platform_deallocate_memory);

enum
{
    PlatformAccess_Read = 0x1,
    PlatformAccess_Write = 0x2,
};
typedef u32 platform_access_flags;

struct platform_file_handle
{
    u64 Platform;
    b32 IsValid;
};

#define PLATFORM_OPEN_FILE(name) platform_file_handle name(string Path, platform_access_flags FileAccess)
typedef PLATFORM_OPEN_FILE(platform_open_file);

#define PLATFORM_CLOSE_FILE(name) void name(platform_file_handle Handle)
typedef PLATFORM_CLOSE_FILE(platform_close_file);

#define PLATFORM_READ_FILE(name) void name(platform_file_handle Handle, void *Dest, u64 Offset, u64 Size)
typedef PLATFORM_READ_FILE(platform_read_file);

#define PLATFORM_WRITE_FILE(name) void name(platform_file_handle Handle, void *Source, u64 Offset, u64 Size)
typedef PLATFORM_WRITE_FILE(platform_write_file);

#define PLATFORM_GET_FILE_SIZE(name) u64 name(platform_file_handle Handle)
typedef PLATFORM_GET_FILE_SIZE(platform_get_file_size);

enum platform_cursor
{
    PlatformCursor_Arrow,
    PlatformCursor_Cross,
    PlatformCursor_Hand,
    PlatformCursor_Help,
    PlatformCursor_IBeam,
    PlatformCursor_SlashedCircle,
    PlatformCursor_ArrowAll,
    PlatformCursor_ArrowNESW,
    PlatformCursor_ArrowVertical,
    PlatformCursor_ArrowNWSE,
    PlatformCursor_ArrowHorizontal,
    PlatformCursor_Wait,
    
    PlatformCursor_Count
};

#define PLATFORM_SET_CURSOR(name) void name(platform_cursor Cursor)
typedef PLATFORM_SET_CURSOR(platform_set_cursor);

#define PLATFORM_TOGGLE_FULLSCREEN(name) void name(void)
typedef PLATFORM_TOGGLE_FULLSCREEN(platform_toggle_fullscreen);

enum platform_message_type
{
    Platform_Message_Info,
    Platform_Message_Warning,
    Platform_Message_Error,
    Platform_Message_Fatal,
};

#define PLATFORM_SHOW_MESSAGE(name) void name(string Message, platform_message_type Type)
typedef PLATFORM_SHOW_MESSAGE(platform_show_message);

struct platform_api
{
    platform_allocate_memory *AllocateMemory;
    platform_deallocate_memory *DeallocateMemory;
    
    platform_open_file *OpenFile;
    platform_close_file *CloseFile;
    platform_read_file *ReadFile;
    platform_write_file *WriteFile;
    platform_get_file_size *GetFileSize;
    
    platform_set_cursor *SetCursor;
    platform_toggle_fullscreen *ToggleFullscreen;
    platform_show_message *ShowMessage;
};

enum platform_event_type
{
    PlatformEvent_Press,
    PlatformEvent_Release,
    PlatformEvent_Text,
    PlatformEvent_MouseScroll,
    PlatformEvent_WindowClose,
};

enum platform_key
{
    Key_Invalid,
    
    Key_A, Key_B, Key_C, Key_D,
    Key_E, Key_F, Key_G, Key_H,
    Key_I, Key_J, Key_K, Key_L,
    Key_M, Key_N, Key_O, Key_P,
    Key_Q, Key_R, Key_S, Key_T,
    Key_U, Key_V, Key_W, Key_X,
    Key_Y, Key_Z,
    
    Key_F1, Key_F2,  Key_F3,  Key_F4,
    Key_F5, Key_F6,  Key_F7,  Key_F8,
    Key_F9, Key_F10, Key_F11, Key_F12,
    
    Key_Left, Key_Right, Key_Up, Key_Down,
    
    Key_Space,
    
    Key_PageUp, Key_PageDown,
    Key_Home, Key_End,
    
    Key_Backspace, Key_Delete,
    
    Key_MouseLeft, Key_MouseMiddle, Key_MouseRight, 
};

typedef u32 platform_modifiers;
enum
{
    PlatformModifier_Ctrl          = (1 << 0),
    PlatformModifier_Shift         = (1 << 1),
    PlatformModifier_Alt           = (1 << 2),
    
    PlatformModifier_DoesNotMatter = -1
};

struct platform_event
{
    platform_event *Next;
    platform_event *Prev;
    platform_event_type Type;
    platform_modifiers Modifiers;
    platform_key Key;
    u32 Codepoint;
    v2 P;
    v2 Scroll;
};

struct platform_event_list
{
    platform_event *First;
    platform_event *Last;
};

static platform_api Platform;

// sixten: Services that the render backend provides to the application

#include "vn_render.h"

#define RENDER_ALLOCATE_TEXTURE(name) render_handle name(v2s Dim, render_texture_format Format, void *Data)
typedef RENDER_ALLOCATE_TEXTURE(render_allocate_texture);

#define RENDER_FILL_REGION(name) void name(render_handle Handle, v2s DestP, v2s DestDim, void *Data)
typedef RENDER_FILL_REGION(render_fill_region);

struct vn_render_commands
{
    render_allocate_texture *AllocateTexture;
    render_fill_region *FillRegion;
    
    render_handle WhiteTexture;
    
    u64 MaxPushBufferSize;
    u8 *PushBufferBase;
    u8 *PushBufferAt;
    
    s32 MaxQuadVertexCount;
    quad_vertex *QuadVertexBase;
    s32 QuadVertexCount;
    
    s32 MaxQuadIndexCount;
    s32 *QuadIndexBase;
    s32 QuadIndexCount;
    
    v2 RenderDim;
};

#include "vn_memory.h"
#include "vn_string.h"
#include "vn_thread_context.h"

// sixten: Services the application provides to the platform

struct vn_input
{
    // sixten: Platform to application
    platform_event_list *EventList;
    
    v2 MouseP;
    v2 dMouseP;
    
    r32 dtForFrame;
    
    // sixten: Application to platform
    s32 RefreshRate;
    b32 ExitRequested;
};

struct vn_memory
{
    platform_api PlatformAPI;
    
    struct vn_state *State;
};

#define VN_UPDATE_AND_RENDER(name) void name(thread_context *ThreadContext, vn_memory *Memory, vn_input *Input, vn_render_commands *RenderCommands)
typedef VN_UPDATE_AND_RENDER(vn_update_and_render);

#endif //VN_PLATFORM_H