; ==============================================================================
; EBLAN ENGINE 3D - Standalone Retro Raycaster Engine
; Pure x86 Assembly (MASM32) | Software 2.5D DIBits Raycaster
; ==============================================================================

.386
.model flat, stdcall
option casemap:none

; Standard Windows Libraries
includelib kernel32.lib
includelib user32.lib
includelib gdi32.lib
includelib winmm.lib

; Windows API Prototypes
ExitProcess             PROTO :DWORD
GetModuleHandleA        PROTO :DWORD
GetCommandLineA         PROTO
GetFileSize             PROTO :DWORD, :DWORD
GetForegroundWindow     PROTO
RegisterClassExA        PROTO :DWORD
CreateWindowExA         PROTO :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD
ShowWindow              PROTO :DWORD, :DWORD
UpdateWindow            PROTO :DWORD
GetDC                   PROTO :DWORD
ReleaseDC               PROTO :DWORD, :DWORD
DefWindowProcA          PROTO :DWORD, :DWORD, :DWORD, :DWORD
PeekMessageA            PROTO :DWORD, :DWORD, :DWORD, :DWORD, :DWORD
TranslateMessage        PROTO :DWORD
DispatchMessageA        PROTO :DWORD
PostQuitMessage         PROTO :DWORD
StretchDIBits           PROTO :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD
GetAsyncKeyState        PROTO :DWORD
GetTickCount            PROTO
Sleep                   PROTO :DWORD
timeBeginPeriod         PROTO :DWORD
timeEndPeriod           PROTO :DWORD
AdjustWindowRect        PROTO :DWORD, :DWORD, :DWORD
LoadCursorA             PROTO :DWORD, :DWORD
CreateFileA             PROTO :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD, :DWORD
ReadFile                PROTO :DWORD, :DWORD, :DWORD, :DWORD, :DWORD
WriteFile               PROTO :DWORD, :DWORD, :DWORD, :DWORD, :DWORD
CloseHandle             PROTO :DWORD
PlaySoundA              PROTO :DWORD, :DWORD, :DWORD
OpenFileMappingA        PROTO :DWORD, :DWORD, :DWORD
MapViewOfFile           PROTO :DWORD, :DWORD, :DWORD, :DWORD, :DWORD
UnmapViewOfFile         PROTO :DWORD
OpenProcess             PROTO :DWORD, :DWORD, :DWORD
WaitForSingleObject     PROTO :DWORD, :DWORD

; Structures
POINT STRUCT
    x dd 0
    y dd 0
POINT ENDS

MSG STRUCT
    hwnd    dd 0
    message dd 0
    wParam  dd 0
    lParam  dd 0
    time    dd 0
    pt      POINT <>
MSG ENDS

RECT STRUCT
    left   dd 0
    top    dd 0
    right  dd 0
    bottom dd 0
RECT ENDS

WNDCLASSEXA STRUCT
    cbSize        dd 0
    style         dd 0
    lpfnWndProc   dd 0
    cbClsExtra    dd 0
    cbWndExtra    dd 0
    hInstance     dd 0
    hIcon         dd 0
    hCursor       dd 0
    hbrBackground dd 0
    lpszMenuName  dd 0
    lpszClassName dd 0
    hIconSm       dd 0
WNDCLASSEXA ENDS

BITMAPINFOHEADER STRUCT
    biSize          dd 0
    biWidth         dd 0
    biHeight        dd 0
    biPlanes        dw 0
    biBitCount      dw 0
    biCompression   dd 0
    biSizeImage     dd 0
    biXPelsPerMeter dd 0
    biYPelsPerMeter dd 0
    biClrUsed       dd 0
    biClrImportant  dd 0
BITMAPINFOHEADER ENDS

; ------------------------------------------------------------------------------
; Engine Includes
; ------------------------------------------------------------------------------
include include/engine_defs.inc
include include/font8x8.inc
include include/engine_data.inc
include include/engine_math.inc
include include/engine_map.inc
include include/engine_textures.inc
include include/engine_input.inc
include include/engine_physics.inc
include include/engine_entity.inc
include include/engine_raycaster.inc
include include/engine_render2d.inc
include include/engine_combat.inc
include include/engine_cutscene.inc
include include/engine_preview.inc

.code

; ------------------------------------------------------------------------------
; Window Procedure Callback
; ------------------------------------------------------------------------------
WndProc PROC hWnd:DWORD, uMsg:DWORD, wParam:DWORD, lParam:DWORD
    cmp uMsg, 0002h             ; WM_DESTROY
    je handle_destroy
    cmp uMsg, 0100h             ; WM_KEYDOWN
    je handle_keydown

    invoke DefWindowProcA, hWnd, uMsg, wParam, lParam
    ret

handle_keydown:
    cmp wParam, VK_KEY_ESCAPE
    jne check_f12
    invoke PostQuitMessage, 0
    mov isRunning, 0
    xor eax, eax
    ret
check_f12:
    ; Movement and action edges are handled only by PollInput.
    invoke DefWindowProcA, hWnd, uMsg, wParam, lParam
    ret

handle_destroy:
    invoke PostQuitMessage, 0
    mov isRunning, 0
    xor eax, eax
    ret
WndProc ENDP

; ------------------------------------------------------------------------------
; Engine_Init: Initializes subsystem, window, math tables and level
; ------------------------------------------------------------------------------
Engine_Init PROC uses ebx esi edi
    LOCAL wc:WNDCLASSEXA
    LOCAL rc:RECT

    invoke timeBeginPeriod, 1

    ; 1. Initialize Engine Subsystems
    call InitMathTables
    call GenerateDefaultTextures    ; Procedural baseline (always valid)
    call LoadTexturePack            ; Optional: override from assets\textures\texturepack.bin
    call LoadMapBinary              ; Loads assets/map.dat (falls back to InitMap if missing)

    ; 2. Register Window Class
    invoke GetModuleHandleA, 0
    mov hEngineInstance, eax

    mov wc.cbSize, sizeof WNDCLASSEXA
    mov wc.style, 0003h         ; CS_HREDRAW | CS_VREDRAW
    mov wc.lpfnWndProc, OFFSET WndProc
    mov wc.cbClsExtra, 0
    mov wc.cbWndExtra, 0
    push hEngineInstance
    pop wc.hInstance
    mov wc.hIcon, 0
    invoke LoadCursorA, 0, 32512 ; IDC_ARROW
    mov wc.hCursor, eax
    mov wc.hbrBackground, 0     ; NULL brush (we draw entire frame)
    mov wc.lpszMenuName, 0
    mov wc.lpszClassName, OFFSET szClassName
    mov wc.hIconSm, 0

    invoke RegisterClassExA, ADDR wc

    ; 3. Adjust Window Client Rect to 1280x960
    mov rc.left, 0
    mov rc.top, 0
    mov rc.right, WINDOW_W
    mov rc.bottom, WINDOW_H
    invoke AdjustWindowRect, ADDR rc, 00CF0000h, 0 ; WS_OVERLAPPEDWINDOW

    ; Calculate dimensions with borders
    mov eax, rc.right
    sub eax, rc.left
    mov ebx, rc.bottom
    sub ebx, rc.top

    ; 4. Create Main Window
    invoke CreateWindowExA, 0, OFFSET szClassName, OFFSET szWindowTitle,\
           00CF0000h, 100, 50, eax, ebx, 0, 0, hEngineInstance, 0
    mov hEngineWnd, eax

    invoke ShowWindow, hEngineWnd, 1 ; SW_SHOWNORMAL
    invoke UpdateWindow, hEngineWnd
    invoke GetDC, hEngineWnd
    mov hEngineDC, eax

    invoke GetTickCount
    mov lastTickCount, eax
    mov fpsTimer, eax

    ret
Engine_Init ENDP

; ------------------------------------------------------------------------------
; Engine_RenderHUD: Draws 2D overlay text, controls, minimap, and FPS
; ------------------------------------------------------------------------------
Engine_RenderHUD PROC uses ebx ecx edx
    cmp isCutsceneActive, 0
    je normal_engine_hud
    call RenderCutsceneOverlay
    ret
normal_engine_hud:
    ; 1. Top HUD Header
    invoke DrawString8x8, 10, 10, OFFSET strEngineName, COLOR_YELLOW

    ; 2. FPS Counter
    invoke DrawString8x8, 10, 24, OFFSET szFpsLabel, COLOR_CYAN
    invoke DrawNumber8x8, 42, 24, currentFps, COLOR_CYAN

    ; 3. Controls Bar at Bottom
    invoke DrawRect, 0, 215, SCREEN_W, 25, 00101010h
    invoke DrawString8x8, 10, 218, OFFSET strControls1, COLOR_WHITE
    invoke DrawString8x8, 10, 228, OFFSET strControls3, COLOR_GREEN

    ; 4. Door / Portal Interaction Hint (center screen)
    call CheckDoorHint
    cmp eax, 1
    je show_door_hint
    cmp eax, 2
    je show_portal_hint
    jmp check_minimap

show_door_hint:
    invoke DrawString8x8, 128, 150, OFFSET strDoorHint, COLOR_YELLOW
    jmp check_minimap

show_portal_hint:
    invoke DrawString8x8, 110, 150, OFFSET strPortalHint, COLOR_CYAN

check_minimap:
    cmp mapErrorFrames, 0
    je hud_no_map_error
    invoke DrawString8x8, 44, 164, OFFSET strMapLoadError, COLOR_RED
hud_no_map_error:
    ; 5. Minimap Radar (Toggle with 'M')
    call DrawMinimap

    ret
Engine_RenderHUD ENDP

; ------------------------------------------------------------------------------
; Engine_Frame: Updates single tick and presents frame buffer to window
; ------------------------------------------------------------------------------
Engine_Frame PROC uses ebx esi edi
    ; 1. Input & Physics Update
    cmp mapErrorFrames, 0
    je no_error_tick
    dec mapErrorFrames
no_error_tick:
    call PollInput
    call UpdatePlayer
    call UpdateEntities
    call UpdateCombat

    ; 2. 3D Raycasting & 2D HUD Render
    call Render3DScene
    call Engine_RenderHUD
    cmp isCutsceneActive, 0
    jne @F
    call RenderCombatHUD
@@:
    call ApplyCutsceneFade

    ; 2b. Screenshot request (F12): dump fresh framebuffer to BMP
    cmp keyScreenshot, 0
    je @F
    mov keyScreenshot, 0
    call SaveScreenshot
@@:

    ; 2c. Screen Fade effect for sublevel transitions
    call ApplyScreenFade

    ; 3. Present Framebuffer to Screen via StretchDIBits (320x240 -> 1280x960)
    invoke StretchDIBits, hEngineDC,\
           0, 0, WINDOW_W, WINDOW_H,\
           0, 0, SCREEN_W, SCREEN_H,\
           OFFSET screenBuffer, OFFSET bmiEngine,\
           0, 00CC0020h         ; DIB_RGB_COLORS, SRCCOPY

    ; 4. Update FPS Counter
    inc fpsCounter
    invoke GetTickCount
    mov edx, eax
    sub edx, fpsTimer
    cmp edx, 1000
    jl frame_done

    ; 1 second elapsed: update currentFps
    mov eax, fpsCounter
    mov currentFps, eax
    mov fpsCounter, 0
    invoke GetTickCount
    mov fpsTimer, eax

frame_done:
    ; Reset one-frame input triggers
    mov keyForward, 0
    mov keyBackward, 0
    mov keyStrafeLeft, 0
    mov keyStrafeRight, 0
    mov keyTurnLeft, 0
    mov keyTurnRight, 0
    mov keyAction, 0
    mov keyAttack, 0
    mov keyRestart, 0
    ret
Engine_Frame ENDP

; ------------------------------------------------------------------------------
; SaveScreenshot: Dumps screenBuffer to screenshot.bmp (32-bit top-down BMP)
; ------------------------------------------------------------------------------
SaveScreenshot PROC uses ebx
    LOCAL hFile:DWORD, bytesWritten:DWORD

    invoke CreateFileA, OFFSET szScreenshotPath, GENERIC_WRITE, 0, 0,\
           CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0
    mov hFile, eax
    cmp eax, INVALID_HANDLE_VALUE
    je ss_done

    invoke WriteFile, hFile, OFFSET screenshotHeader, 54, ADDR bytesWritten, 0
    invoke WriteFile, hFile, OFFSET screenBuffer, FRAME_BUFFER_SIZE, ADDR bytesWritten, 0
    invoke CloseHandle, hFile
ss_done:
    ret
SaveScreenshot ENDP

; Optional first argument: a quoted or unquoted starting map path.
; Assets and linked map basenames remain relative to the working directory.
ParseStartupMap PROC uses ebx ecx edx esi edi
    invoke GetCommandLineA
    mov esi, eax
    mov startupMapPath, 0
    cmp byte ptr [esi], 34
    jne skip_executable_word
    inc esi
skip_executable_quote:
    lodsb
    test al, al
    jz startup_arg_done
    cmp al, 34
    jne skip_executable_quote
    jmp skip_argument_spaces
skip_executable_word:
    lodsb
    test al, al
    jz startup_arg_done
    cmp al, 32
    jne skip_executable_word
skip_argument_spaces:
    cmp byte ptr [esi], 32
    je consume_argument_space
    cmp byte ptr [esi], 9
    jne copy_startup_argument
consume_argument_space:
    inc esi
    jmp skip_argument_spaces
copy_startup_argument:
    xor ebx, ebx
    cmp byte ptr [esi], 34
    jne startup_argument_loop_init
    mov ebx, 1
    inc esi
startup_argument_loop_init:
    mov edi, OFFSET startupMapPath
    mov ecx, MAX_PATH_BYTES - 1
startup_argument_loop:
    lodsb
    test al, al
    jz terminate_startup_arg
    cmp al, 34
    je terminate_startup_arg
    test ebx, ebx
    jnz write_startup_char
    cmp al, 32
    je terminate_startup_arg
    cmp al, 9
    je terminate_startup_arg
write_startup_char:
    stosb
    dec ecx
    jnz startup_argument_loop
    mov startupMapPath, 0
    ret
terminate_startup_arg:
    mov byte ptr [edi], 0
startup_arg_done:
    ret
ParseStartupMap ENDP

; ------------------------------------------------------------------------------
; main: Application Entry Point & Game Loop
; ------------------------------------------------------------------------------
main PROC
    LOCAL msg:MSG
    LOCAL curTick:DWORD, elapsed:DWORD

    call ParseStartupMap
    call TryEnginePreview
    call Engine_Init

main_loop:
    cmp isRunning, 0
    je exit_loop

    ; Process Window Messages (Non-blocking)
@@:
    invoke PeekMessageA, ADDR msg, 0, 0, 0, 1 ; PM_REMOVE
    test eax, eax
    jz process_game_tick

    cmp msg.message, 0012h      ; WM_QUIT
    je exit_loop

    invoke TranslateMessage, ADDR msg
    invoke DispatchMessageA, ADDR msg
    jmp @B

process_game_tick:
    ; Frame Rate Limiter (~60 FPS)
    invoke GetTickCount
    mov curTick, eax
    sub eax, lastTickCount
    mov elapsed, eax

    mov eax, targetFrameTimeMs
    cmp elapsed, eax
    jge do_tick

    invoke Sleep, 1
    jmp main_loop

do_tick:
    mov eax, curTick
    mov lastTickCount, eax

    call Engine_Frame
    jmp main_loop

exit_loop:
    call StopCutscene
    invoke ReleaseDC, hEngineWnd, hEngineDC
    invoke timeEndPeriod, 1
    invoke ExitProcess, 0
main ENDP

END main