; =============================================================================
;  headsup display  

org $0DFB91
  JSL HUD_Update
  RTS

newIgnoreItemBox:
  JSL HUD_Update_ignoreItemBox
  RTS

org $0DDD21
  JSR newIgnoreItemBox

org $0DF1BC
  JSL HUD_AnimateHeartRefill
  RTS

org $268000
HUD_Update:
{
  JSR HUD_UpdateItemBox

.ignoreItemBox ; ALTERNATE ENTRY POINT

  SEP #$30
  
  ; need to draw partial heart still though. 
  LDA.b #$FD : STA $0A
  LDA.b #$F9 : STA $0B
  LDA.b #$0D : STA $0C
  
  LDA.b #$44 : STA $07
  LDA.b #$C7 : STA $08
  LDA.b #$7E : STA $09
  
  REP #$30
  
  ; Load Capacity health.
  LDA $7EF36C : AND.w #$00FF : STA $00 : STA $02 : STA $04
  
  ; First, just draw all the empty hearts (capacity health)
  JSR HUD_UpdateHearts
  
  SEP #$30
  
  LDA.b #$03 : STA $0A
  LDA.b #$FA : STA $0B
  LDA.b #$0D : STA $0C
  
  LDA.b #$44 : STA $07
  LDA.b #$C7 : STA $08
  LDA.b #$7E : STA $09
  
  ; Branch if at full health
  LDA $7EF36C : CMP $7EF36D : BEQ .healthUpdated
  
  ; Seems absurd to have a branch of zero bytes, right?
  SEC : SBC #$04 : CMP $7EF36D : BCS .healthUpdated

.healthUpdated

  ; A = actual health + 0x03;
  LDA $7EF36D : SEC : SBC #$03
  
  REP #$30
  
  AND.w #$00FC : STA $00 : STA $04
  
  LDA $7EF36C : AND.w #$00FF : STA $02
  
  ; filling in the full and partially filled hearts (actual health)
  JSR HUD_UpdateHearts

.ignoreHealth ; *$6FC09 ALTERNATE ENTRY POINT ; reentry hook

  REP #$30
  
  ; Magic amount indicator (normal, 1/2, or 1/4)
  LDA $7EF37B : AND.w #$00FF : CMP.w #$0001 : BCC .normalMagicMeter
  
  ; draw 1/2 magic meter 
  LDA.w #$2851 : STA $7EC730
  LDA.w #$28FA : STA $7EC732

.normalMagicMeter

  ; check player magic (ranges from 0 to 0x7F)
  ; X = ((MP & 0xFF)) + 7) & 0xFFF8)
  ; LDA $7EF36E : AND.w #$00FF : CLC : ADC #$0007 : AND.w #$FFF8 : TAX
  
  ; these four writes draw the magic power bar based on how much MP you have 
  ; LDA MagicTilemap+0, X : STA $7EC746
  ; LDA MagicTilemap+2, X : STA $7EC786
  ; LDA MagicTilemap+4, X : STA $7EC7C6
  ; LDA MagicTilemap+6, X : STA $7EC806
  
  ; Load how many rupees the player has
  LDA $7EF362
  
  JSR HexToDecimal
  
  REP #$30
  
  ; The tile index for the first rupee digit
  LDA $03 : AND.w #$00FF : ORA.w #$2400 : STA $7EC79C
  
  ; The tile index for the second rupee digit
  LDA $04 : AND.w #$00FF : ORA.w #$2400 : STA $7EC79E
  
  ; The tile index for the third rupee digit
  LDA $05 : AND.w #$00FF : ORA.w #$2400 : STA $7EC7A0
  
  ; Number of bombs Link has.
  LDA $7EF343 : AND.w #$00FF
  
  JSR HexToDecimal
  
  REP #$30
  
  ; The tile index for the first bomb digit
  LDA $04 : AND.w #$00FF : ORA.w #$2400 : STA $7EC7B0
  
  ; The tile index for the second bomb digit
  LDA $05 : AND.w #$00FF : ORA.w #$2400 : STA $7EC7B2
  
  ; ; Number of Arrows Link has.
  ; LDA $7EF377 : AND.w #$00FF
  
  ;   ; converts hex to up to 3 decimal digits
  ;   JSR HexToDecimal
    
  ;   REP #$30
    
  ;   ; The tile index for the first arrow digit    
  ;   LDA $04 : AND.w #$00FF : ORA.w #$2400 : STA $7EC75E
    
  ;   ; The tile index for the second arrow digit   
  ;   LDA $05 : AND.w #$00FF : ORA.w #$2400 : STA $7EC760
    
  ;   LDA.w #$007F : STA $05
    
  ;   ; Load number of Keys Link has
  ;   LDA $7EF36F : AND.w #$00FF : CMP.w #$00FF : BEQ .noKeys
    
  ;   JSR HexToDecimal

  ; .noKeys
  
  ;   REP #$30
    
  ;   ; The key digit, which is optionally drawn.
  ;   ; Also check to see if the key spot is blank
  ;   LDA $05 : AND.w #$00FF : ORA.w #$2400 : STA $7EC764
    
  ;   CMP.w #$247F : BNE .dontBlankKeyIcon
    
  ;   ; If the key digit is blank, also blank out the key icon.
  ;   STA $7EC724
  
  ; .dontBlankKeyIcon

  ;   SEP #$30

    RTL
}

; =============================================================================
; *$6DB92-$6DD29 BRANCH LOCATION

HUD_RefillLogic:
{
  ; Check current rupees (362) against goal rupees (360)
  ; goal refers to how many we really have and current refers to the
  ; number currently being displayed. When you buy something,
  ; goal rupees are decreased by, say, 100, but it takes a while for the 
  ; current rupees indicator to catch up. When you get a gift of 300
  ; rupees, the goal increases, and current has to catch up in the other direction.
  LDA $7EF362
  
  CMP $7EF360 : BEQ .doneWithRupeesRefill
                BMI .addRupees
  DEC A       : BPL .subtractRupees
  
  LDA.w #$0000 : STA $7EF360
  
  BRA .subtractRupees

.addRupees

  ; If current rupees <= 1000 (decimal)
  INC A : CMP.w #1000 : BCC .subtractRupees
  
  ; Otherwise just store 999 to the rupee amount
  LDA.w #999 : STA $7EF360

.subtractRupees

  STA $7EF362
  
  SEP #$30
  
  LDA $012E : BNE .doneWithRupeesRefill
  
  ; looks like a delay counter of some sort between
  ; invocations of the rupee fill sound effect
  LDA $0CFD : INC $0CFD : AND.b #$07 : BNE .skipRupeeSound
  
  LDA.b #$29 : STA $012E

  BRA .skipRupeeSound

.doneWithRupeesRefill

  SEP #$30
  
  STZ $0CFD

.skipRupeeSound

  LDA $7EF375

  BEQ .doneRefillingBombs

  ; decrease the bomb refill counter
  LDA $7EF375 : DEC A : STA $7EF375

  ; use the bomb upgrade index to know what max number of bombs Link can carry is
  LDA $7EF370 : TAY

  ; if it matches the max, you can't have no more bombs, son. It's the law.
  LDA $7EF343 : CMP $DB48, Y : BEQ .doneRefillingBombs
  
  ; You like bombs? I got lotsa bombs!
  INC A : STA $7EF343

.doneRefillingBombs

  ; check arrow refill counter
  LDA $7EF376
  
  BEQ .doneRefillingArrows
  
  LDA $7EF376 : DEC A : STA $7EF376
  
  ; check arrow upgrade index to see how our max limit on arrows, just like bombs.
  LDA $7EF371 : TAY 
  
  LDA $7EF377 : CMP $DB58, Y
  
  ; I reckon you get no more arrows, pardner.
  BEQ .arrowsAtMax
  
  INC A : STA $7EF377

.arrowsAtMax

  ; see if we even have the bow.
  LDA $7EF340
  
  BEQ .doneRefillingArrows
  
  AND.b #$01 : CMP.b #$01
  
  BNE .doneRefillingArrows
  
  ; changes the icon from a bow without arrows to a bow with arrows.
  LDA $7EF340 : INC A : STA $7EF340
  
  JSL $0DDB7F

.doneRefillingArrows

  ; a frozen Link is an impervious Link, so don't beep.
  LDA $02E4
  
  BNE .doneWithWarningBeep
  
  ; if heart refill is in process, we don't beep
  LDA $7EF372
  
  BNE .doneWithWarningBeep
  
  LDA $7EF36C : LSR #3 : TAX
  
  ; checking current health against capacity health to see
  ; if we need to put on that annoying beeping noise.
  LDA $7EF36D : CMP $DB60, X
  
  BCS .doneWithWarningBeep
  
  LDA $04CA
  
  BNE .decrementBeepTimer
  
  ; beep incessantly when life is low
  LDA $012E
  
  BNE .doneWithWarningBeep
  
  LDA.b #$20 : STA $04CA
  LDA.b #$2B : STA $012E

.decrementBeepTimer

  ; Timer for the low life beep sound
  DEC $04CA

.doneWithWarningBeep

  ; if nonzero, indicates that a heart is being "flipped" over
  ; as in, filling up, currently
  LDA $020A
  
  BNE .waitForHeartFillAnimation
  
  ; If no hearts need to be filled, branch
  LDA $7EF372
  
  BEQ .doneRefillingHearts
  
  ; check if actual health matches capacity health
  LDA $7EF36D : CMP $7EF36C
  
  BCC .notAtFullHealth
  
  ; just set health to full in the event it overflowed past 0xA0 (20 hearts)
  LDA $7EF36C : STA $7EF36D
  
  ; done refilling health so deactivate the health refill variable
  LDA.b #$00 : STA $7EF372
  
  BRA .doneRefillingHearts

.notAtFullHealth

  ; refill health by one heart
  LDA $7EF36D : CLC : ADC.b #$08 : STA $7EF36D
  
  LDA $012F
  
  BNE .soundChannelInUse
  
  ; play heart refill sound effect
  LDA.b #$0D : STA $012F

.soundChannelInUse

  ; repeat the same logic from earlier, checking if health's at max and setting it to max
  ; if it overflowed
  LDA $7EF36D : CMP $7EF36C
  
  BCC .healthDidntOverflow
  
  LDA $7EF36C : STA $7EF36D

.healthDidntOverflow

  ; subtract a heart from the refill variable
  LDA $7EF372 : SEC : SBC.b #$08 : STA $7EF372
  
  ; activate heart refill animation
  ; (which will cause a small delay for the next heart if we still need to fill some up.)
  INC $020A
  
  LDA.b #$07 : STA $0208

.waitForHeartFillAnimation

  REP #$30
  
  LDA.w #$FFFF : STA $0E
  
  JSL HUD_Update_ignoreHealth
  
  JSL HUD_AnimateHeartRefill
  
  SEP #$30
  
  INC $16
  
  PLB
  
  RTL

.doneRefillingHearts

  REP #$30
  
  LDA.w #$FFFF : STA $0E
  
  JSL HUD_Update_ignoreItemBox
  
  SEP #$30
  
  INC $16
  
  PLB
  
  RTL
} 

; =============================================================================
; *$6F14F-$6F1B2 LOCAL

HUD_AnimateHeartRefill:
{
  SEP #$30
  
  ; $00[3] = $7EC768 (wram address of first row of hearts in tilemap buffer)
  LDA.b #$44 : STA $00
  LDA.b #$C7 : STA $01
  LDA.b #$7E : STA $02
  
  DEC $0208 : BNE .return
  
  REP #$30
  
  ; Y = ( ( ( (current_health & 0x00F8) - 1) / 8 ) * 2)
  LDA $7EF36D : AND.w #$00F8 : DEC A : LSR #3 : ASL A : TAY : CMP.w #$0014
  
  BCC .halfHealthOrLess
  
  SBC.w #$0014 : TAY
  
  ; $00[3] = $7EC7A8 (wram address of second row of hearts)
  LDA $00 : CLC : ADC.w #$0040 : STA $00

.halfHealthOrLess

  SEP #$30
  
  LDX $0209 : LDA $0DFA11, X : STA $0208
  
  TXA : ASL A : TAX
  
  LDA $0DFA09, X : STA [$00], Y
  
  INY : LDA $0DFA0A, X : STA [$00], Y
  
  LDA $0209 : INC A : AND.b #$03 : STA $0209
  
  BNE .return
  
  SEP #$30
  
  JSL $0DFA70
  
  STZ $020A

.return

  CLC
  
  RTS
}

; ============================================================================ 
; *$6FAFD-$6FB90 LOCAL

HUD_UpdateItemBox:
{
    SEP #$30
    
    ; Dost thou haveth the the bow?
    LDA $7EF340 : BEQ .havethNoBow
    
    ; Dost thou haveth the silver arrows?
    ; (okay I'll stop soon)
    ; CMP.b #$03 : BCC .havethNoSilverArrows 
    
    ; Draw the arrow guage icon as silver rather than normal wood arrows.
;     LDA.b #$86 : STA $7EC71E
;     LDA.b #$24 : STA $7EC71F
;     LDA.b #$87 : STA $7EC720
;     LDA.b #$24 : STA $7EC721
    
    LDX.b #$04
    
    ; check how many arrows the player has
    LDA $7EF377 : BNE .drawBowItemIcon
    
    LDX.b #$03
    
    BRA .drawBowItemIcon

; .havethNoSilverArrows

;     LDX.b #$02
    
;     LDA $7EF377 : BNE .drawBowItemIcon
    
;     LDX.b #$01

.drawBowItemIcon

    ; values of X correspond to how the icon will end up drawn:
    ; 0x01 - normal bow with no arrows
    ; 0x02 - normal bow with arrows
    ; 0x03 - silver bow with no silver arrows
    ; 0x04 - silver bow with silver arrows
    TXA : STA $7EF340

.havethNoBow

    REP #$30
    
    LDX $0202 : BEQ .noEquippedItem
    
    LDA $7EF33F, X : AND.w #$00FF
    
    CPX.w #$0004 : BNE .bombsNotEquipped
    
    LDA.w #$0001
    
.bombsNotEquipped

    CPX.w #$0010 : BNE .bottleNotEquipped
    
    TXY : TAX : LDA $7EF35B, X : AND.w #$00FF : TYX

.bottleNotEquipped

    STA $02
    
    TXA : DEC A : ASL A : TAX
    
    LDA $FA93, X : STA $04
    
    LDA $02 : ASL #3 : TAY
    
    ; These addresses form the item box graphics.
    LDA ($04), Y : STA $7EC776 : INY #2
    LDA ($04), Y : STA $7EC778 : INY #2
    LDA ($04), Y : STA $7EC7B6 : INY #2
    LDA ($04), Y : STA $7EC7B8 : INY #2

.noEquippedItem

    RTS
}

; =============================================================================

HUD_UpdateHearts:
{
    ; Draws hearts in a painfully slow loop
    ; I used DMA to speed it up in my custom code
    ; (but still needs fixing to work on 1/1/1 hardware)
    
    LDX.w #$0000

.nextHeart

    LDA $00 : CMP.w #$0008 : BCC .lessThanOneHeart
    
    ; Notice no SEC was needed since carry is assumedly set.
    SBC.w #$0008 : STA $00
    
    LDY.w #$0004
    
    JSR .drawHeart
    
    INX #2
    
    BRA .nextHeart

.lessThanOneHeart

    CMP.w #$0005 : BCC .halfHeartOrLess
    
    LDY.w #$0004
    
    BRA .drawHeart

.halfHeartOrLess

    CMP.w #$0001 : BCC .emptyHeart
    
    LDY.w #$0002
    
    BRA .drawHeart

.emptyHeart

    RTS

.drawHeart

    ; Compare number of hearts so far on current line to 10
    CPX.w #$0014 : BCC .noLineChange
    
    ; if not, we have to move down one tile in the tilemap
    LDX.w #$0000
    
    LDA $07 : CLC : ADC #$0040 : STA $07

.noLineChange

    LDA [$0A], Y : TXY : STA [$07], Y
    
    RTS
}

; =============================================================================

MagicTilemap:
  dw $3CF5, $3CF5, $3CF5, $3CF5
  dw $3CF5, $3CF5, $3CF5, $3C5F
  dw $3CF5, $3CF5, $3CF5, $3C4C
  dw $3CF5, $3CF5, $3CF5, $3C4D
  dw $3CF5, $3CF5, $3CF5, $3C4E
  dw $3CF5, $3CF5, $3C5F, $3C5E
  dw $3CF5, $3CF5, $3C4C, $3C5E
  dw $3CF5, $3CF5, $3C4D, $3C5E
  dw $3CF5, $3CF5, $3C4E, $3C5E
  dw $3CF5, $3C5F, $3C5E, $3C5E
  dw $3CF5, $3C4C, $3C5E, $3C5E
  dw $3CF5, $3C4D, $3C5E, $3C5E
  dw $3CF5, $3C4E, $3C5E, $3C5E
  dw $3C5F, $3C5E, $3C5E, $3C5E
  dw $3C4C, $3C5E, $3C5E, $3C5E
  dw $3C4D, $3C5E, $3C5E, $3C5E
  dw $3C4E, $3C5E, $3C5E, $3C5E  

; =============================================================================

HexToDecimal:
{
    REP #$30
    STZ $0003
    LDX.w #$0000
    LDY.w #$0002
.nextDigit
    CMP $F9F9, Y : BCC .nextLowest10sPlace
    SEC : SBC $F9F9, Y
    INC $03, X
    BRA .nextDigit
.nextLowest10sPlace
    INX : DEY #2
    BPL .nextDigit
    STA $05
    SEP #$30
    LDX.b #$02
.setNextDigitTile
    LDA $03, X : CMP.b #$7F
    BEQ .blankDigit
    ORA.b #$90
.blankDigit
    STA $03, X
    DEX : BPL .setNextDigitTile
    RTS
} 

; =============================================================================
; $6FE77-$6FFC0 

org $0DFE77
HUD_Tilemap:
{
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F
  
  ; magic bar top part
  dw $200B, $200C, $200C, $200C, $200C, $200C
  ; item frame top part 
  dw $206C, $206D, $206E, $206F 

  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F
  
  ; magic bar
  dw $201B, $344B
  dw $344B, $344B, $344B, $344B
  
   ; item frame left part 
  dw $20DE, $207F, $207F, $20DF
                               
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F

  ; magic bar bottom part 
  dw $A00B, $A00C
  dw $A00C, $A00C, $A00C, $A00C

  ; item frame right part 
  dw $20EE, $207F, $207F, $20EF
                                
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F
  
  ; item frame bottom part
  dw $207C, $207D, $207E, $201D

  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F, $207F, $207F, $207F, $207F, $207F, $207F, $207F
  dw $207F
}