; ==============================================================================
; EBLAN ENGINE - Player Combat, Weapon Shooting & Combat HUD
; ==============================================================================

.code

DrawPixel PROTO :DWORD, :DWORD, :DWORD
DrawRect PROTO :DWORD, :DWORD, :DWORD, :DWORD, :DWORD
DrawRectOutline PROTO :DWORD, :DWORD, :DWORD, :DWORD, :DWORD
DrawString8x8 PROTO :DWORD, :DWORD, :DWORD, :DWORD
DrawNumber8x8 PROTO :DWORD, :DWORD, :DWORD, :DWORD

; Trace the current world along the player's forward direction. EAX = first
; blocking boundary in 24.8 world units. Glass blocks shots (unlike rendering).
; No framebuffer/depth-buffer dependencies. Out-of-map cells are solid.
TraceShotWall PROC uses ebx ecx edx esi edi
    LOCAL cellX:DWORD, cellY:DWORD, stepX:DWORD, stepY:DWORD
    LOCAL deltaX:DWORD, deltaY:DWORD, sideX:DWORD, sideY:DWORD
    LOCAL hitDistance:DWORD, remaining:DWORD

    mov eax, playerX
    sar eax, 6
    mov cellX, eax
    mov eax, playerY
    sar eax, 6
    mov cellY, eax
    invoke GetMapCell, cellX, cellY
    invoke IsSolidCell, eax
    test eax, eax
    jnz shot_wall_at_origin

    mov eax, playerAngle
    and eax, ANGLE_MASK
    mov esi, [tableCos+eax*4]
    mov edi, [tableSin+eax*4]
    mov deltaX, 3FFFFFFFh
    mov sideX, 3FFFFFFFh
    mov stepX, 1
    test esi, esi
    jz shot_setup_y
    mov eax, esi
    cdq
    xor eax, edx
    sub eax, edx
    mov ecx, eax
    mov eax, (64 shl 24)
    xor edx, edx
    div ecx
    mov deltaX, eax
    mov eax, playerX
    and eax, 63
    test esi, esi
    js shot_negative_x
    neg eax
    add eax, 64
    jmp shot_side_x
shot_negative_x:
    mov stepX, -1
shot_side_x:
    imul deltaX
    shrd eax, edx, 6
    mov sideX, eax
shot_setup_y:
    mov deltaY, 3FFFFFFFh
    mov sideY, 3FFFFFFFh
    mov stepY, 1
    test edi, edi
    jz shot_traverse_start
    mov eax, edi
    cdq
    xor eax, edx
    sub eax, edx
    mov ecx, eax
    mov eax, (64 shl 24)
    xor edx, edx
    div ecx
    mov deltaY, eax
    mov eax, playerY
    and eax, 63
    test edi, edi
    js shot_negative_y
    neg eax
    add eax, 64
    jmp shot_side_y
shot_negative_y:
    mov stepY, -1
shot_side_y:
    imul deltaY
    shrd eax, edx, 6
    mov sideY, eax
shot_traverse_start:
    mov remaining, MAP_W+MAP_H+2
shot_traverse:
    mov eax, sideX
    cmp eax, sideY
    jb shot_step_x
    jne shot_step_y
    ; At a corner also test the X-adjacent cell: no shots through wall seams.
    mov ebx, cellX
    add ebx, stepX
    invoke GetMapCell, ebx, cellY
    invoke IsSolidCell, eax
    test eax, eax
    jz shot_step_y
    mov eax, sideX
    ret
shot_step_x:
    mov hitDistance, eax
    add eax, deltaX
    mov sideX, eax
    mov eax, stepX
    add cellX, eax
    jmp shot_test_cell
shot_step_y:
    mov eax, sideY
    mov hitDistance, eax
    add eax, deltaY
    mov sideY, eax
    mov eax, stepY
    add cellY, eax
shot_test_cell:
    invoke GetMapCell, cellX, cellY
    invoke IsSolidCell, eax
    test eax, eax
    jnz shot_wall_found
    dec remaining
    jnz shot_traverse
    ; Defensive bound: a valid ray exits a 32x32 map within 64 crossings.
shot_wall_found:
    mov eax, hitDistance
    ret
shot_wall_at_origin:
    xor eax, eax
    ret
TraceShotWall ENDP

; ------------------------------------------------------------------------------
; UpdateCombat: Process weapon firing, hitscan raycasting, cooldowns & damage
; ------------------------------------------------------------------------------
UpdateCombat PROC uses ebx ecx edx esi edi
    LOCAL camCos:DWORD, camSin:DWORD
    LOCAL i:DWORD, closestIdx:DWORD, closestDist:DWORD
    LOCAL sprX:DWORD, sprY:DWORD
    LOCAL transX:DWORD, transY:DWORD
    LOCAL targetHalfWidth:DWORD, wallDepth:DWORD

    call IsGameplayBlocked
    test eax, eax
    jnz combat_done

    ; 1. Decrement cooldowns
    cmp playerAttackCooldown, 0
    je @F
    dec playerAttackCooldown
@@:
    cmp playerFlashTimer, 0
    je @F
    dec playerFlashTimer
@@:
    cmp playerHitFlash, 0
    je @F
    dec playerHitFlash
@@:

    ; If player is dead, cannot attack
    cmp isPlayerDead, 0
    jne combat_done

    ; 2. Check attack input
    cmp keyAttack, 0
    je combat_done
    cmp playerAttackCooldown, 0
    jne combat_done

    ; Check ammo
    cmp playerAmmo, 0
    jle combat_dry_fire

    ; Fire weapon!
    dec playerAmmo
    mov playerAttackCooldown, 10
    mov playerFlashTimer, 5

    ; 3. Hitscan check against enemies in center crosshair
    ; Camera basis for -playerAngle
    mov eax, ANGLE_512
    sub eax, playerAngle
    and eax, ANGLE_MASK
    mov ecx, [tableCos + eax*4]
    mov camCos, ecx
    mov edx, [tableSin + eax*4]
    mov camSin, edx

    ; Query current geometry, never the previous rendered frame.
    call TraceShotWall
    mov wallDepth, eax

    mov closestIdx, -1
    mov closestDist, 999999

    mov i, 0
hitscan_loop:
    mov eax, i
    cmp eax, spriteCount
    jge hitscan_eval

    mov ecx, i
    mov eax, [entityType + ecx*4]
    cmp eax, ENTITY_TYPE_GUARD
    jne next_hitscan_target

    mov eax, [entityState + ecx*4]
    cmp eax, ENTITY_STATE_DEAD
    je next_hitscan_target

    mov ebx, i
    imul ebx, sizeof SpriteStruct
    add ebx, OFFSET spriteList

    mov eax, [ebx].SpriteStruct.textureId
    test eax, eax
    jz next_hitscan_target

    ; Transform to camera space
    mov eax, [ebx].SpriteStruct.x
    sub eax, playerX
    mov sprX, eax

    mov eax, [ebx].SpriteStruct.y
    sub eax, playerY
    mov sprY, eax

    ; transY = sprX * camCos - sprY * camSin
    mov eax, sprX
    imul camCos
    shrd eax, edx, 16
    mov ecx, eax
    mov eax, sprY
    imul camSin
    shrd eax, edx, 16
    sub ecx, eax
    mov transY, ecx

    ; Must be in front of player
    cmp transY, 16
    jle next_hitscan_target

    ; Compare in 24.8 so a target on a wall boundary is not hit through it.
    mov eax, transY
    shl eax, 8
    cmp eax, wallDepth
    jge next_hitscan_target

    ; transX = sprX * camSin + sprY * camCos
    mov eax, sprX
    imul camSin
    shrd eax, edx, 16
    mov ecx, eax
    mov eax, sprY
    imul camCos
    shrd eax, edx, 16
    add ecx, eax
    mov transX, ecx

    ; World-space billboard hitbox: 32 units wide at scale 1.0, scaled with
    ; the authored sprite, never with screen distance. Zero means legacy 1.0.
    mov eax, [ebx].SpriteStruct.scale
    test eax, eax
    jnz @F
    mov eax, FIXED_ONE
@@:
    imul eax, 16
    sar eax, 16
    mov targetHalfWidth, eax
    mov eax, transX
    cdq
    xor eax, edx
    sub eax, edx
    cmp eax, targetHalfWidth
    jg next_hitscan_target

    ; Check if closer than previous target
    mov eax, transY
    cmp eax, closestDist
    jge next_hitscan_target
    mov closestDist, eax
    mov eax, i
    mov closestIdx, eax

next_hitscan_target:
    inc i
    jmp hitscan_loop

hitscan_eval:
    cmp closestIdx, -1
    je combat_done

    ; Apply damage to hit guard
    mov ecx, closestIdx
    mov eax, [entityHealth + ecx*4]
    sub eax, 35
    jns @F
    xor eax, eax
@@:
    mov [entityHealth + ecx*4], eax
    test eax, eax
    jnz combat_done

    ; Guard died!
    mov [entityState + ecx*4], ENTITY_STATE_DEAD
    mov DWORD PTR [entityTimer + ecx*4], 0
    add playerScore, 100

    ; Drop 10 ammo reward
    mov eax, playerAmmo
    add eax, 10
    cmp eax, playerMaxAmmo
    jle @F
    mov eax, playerMaxAmmo
@@:
    mov playerAmmo, eax
    jmp combat_done

combat_dry_fire:
    mov playerAttackCooldown, 12

combat_done:
    ret
UpdateCombat ENDP

; ------------------------------------------------------------------------------
; RenderCombatHUD: Renders health bar, ammo, crosshair, weapon & death screen
; ------------------------------------------------------------------------------
RenderCombatHUD PROC uses ebx ecx edx esi edi
    LOCAL barW:DWORD, gunY:DWORD

    ; 1. Center Crosshair (subtle cross at 160, 120)
    invoke DrawRect, 156, 120, 9, 1, 00FFFFFFh
    invoke DrawRect, 160, 116, 1, 9, 00FFFFFFh
    invoke DrawRect, 160, 120, 1, 1, 0000FF00h

    ; 2. Render Retro Weapon at bottom center
    mov gunY, 192
    cmp playerFlashTimer, 0
    je draw_gun_barrel
    ; Recoil offset
    add gunY, 3

    ; Muzzle Flash Burst (Bright yellow & white star)
    invoke DrawRect, 157, 165, 7, 18, 00FFFF00h
    invoke DrawRect, 152, 170, 17, 8, 00FFAA00h
    invoke DrawRect, 158, 168, 5, 12, 00FFFFFFh

draw_gun_barrel:
    ; Weapon barrel & slide
    invoke DrawRect, 154, gunY, 13, 28, 003A3A3Ah
    invoke DrawRect, 156, gunY, 9, 28, 00555555h
    invoke DrawRect, 158, gunY, 5, 28, 00777777h ; highlight strip
    ; Gun frame & grip
    mov eax, gunY
    add eax, 24
    invoke DrawRect, 150, eax, 21, 24, 00252525h
    mov eax, gunY
    add eax, 26
    invoke DrawRect, 152, eax, 17, 22, 00453020h ; brown wood grip plates

    ; 3. Health Bar
    invoke DrawString8x8, 8, 42, OFFSET strHpLabel, COLOR_GREEN
    invoke DrawNumber8x8, 34, 42, playerHealth, COLOR_WHITE

    invoke DrawRect, 68, 42, 60, 8, 00441010h
    invoke DrawRectOutline, 68, 42, 60, 8, COLOR_WHITE

    mov eax, playerHealth
    imul eax, 58
    xor edx, edx
    mov ecx, playerMaxHealth
    test ecx, ecx
    jnz @F
    mov ecx, 100
@@:
    div ecx
    mov barW, eax
    cmp barW, 0
    jle hud_ammo_draw
    cmp barW, 58
    jle @F
    mov barW, 58
@@:
    mov edx, 0000CC33h ; Green
    cmp playerHealth, 30
    jg @F
    mov edx, 00FF2222h ; Red warning
@@:
    invoke DrawRect, 69, 43, barW, 6, edx

hud_ammo_draw:
    ; 4. Ammo Display
    invoke DrawString8x8, 140, 42, OFFSET strAmmoLabel, COLOR_YELLOW
    invoke DrawNumber8x8, 182, 42, playerAmmo, COLOR_YELLOW

    ; 5. Score Display
    invoke DrawString8x8, 222, 42, OFFSET strScoreLabel, COLOR_CYAN
    invoke DrawNumber8x8, 272, 42, playerScore, COLOR_CYAN

    ; 6. Keys (if collected)
    cmp playerKeys, 0
    jle hud_damage_flash
    invoke DrawString8x8, 222, 10, OFFSET strKeysLabel, COLOR_MAGENTA
    invoke DrawNumber8x8, 258, 10, playerKeys, COLOR_MAGENTA

hud_damage_flash:
    ; 7. Damage Screen Flash
    cmp playerHitFlash, 0
    jle hud_death_check
    ; Red border vignette
    invoke DrawRect, 0, 0, SCREEN_W, 3, 00FF0000h
    invoke DrawRect, 0, 237, SCREEN_W, 3, 00FF0000h
    invoke DrawRect, 0, 0, 3, SCREEN_H, 00FF0000h
    invoke DrawRect, 317, 0, 3, SCREEN_H, 00FF0000h

hud_death_check:
    ; 8. Death Overlay Screen
    cmp isPlayerDead, 0
    je combat_hud_done

    invoke DrawRect, 20, 95, 280, 50, 00880000h
    invoke DrawRectOutline, 20, 95, 280, 50, COLOR_WHITE
    invoke DrawString8x8, 32, 114, OFFSET strYouDied, COLOR_YELLOW

combat_hud_done:
    ret
RenderCombatHUD ENDP