;****************************************************************************
; MainMenu
; Menu where you get to select the song and such
; The main screen, bah...
;****************************************************************************

MainMenu:
    move.w  #0, (RAM_CurrSong)      ; Selected song
    bsr     UpdateMenu              ; Show description of first song

    move.l  #0, (RAM_LArrowAnim)    ; Reset arrows anim
    move.w  #$8407, (RAM_BGAnim)    ; Reset background anim

@MainLoop:
    move.b  (RAM_JoyPress), d0      ; Get joypad input

    btst.l  #2, d0                  ; Previous song?
    beq.s   @NoLeft

    move.w  (RAM_CurrSong), d7        ; Select previous song
    bne.s   @NotTooLeft
    move.w  #NumSongs, d7
@NotTooLeft:
    subq.w  #1, d7
    move.w  d7, (RAM_CurrSong)

    bsr     UpdateMenu                ; Update current song
    move.w  #28, (RAM_LArrowAnim)     ; Animate left arrow
    lea     (SFX_Beep), a0            ; Beep!
    bsr     Echo_PlaySFX
@NoLeft:

    btst.l  #3, d0                  ; Next song?
    beq.s   @NoRight

    move.w  (RAM_CurrSong), d7        ; Select next song
    addq.w  #1, d7
    cmp.w   #NumSongs, d7
    blt.s   @NotTooRight
    moveq   #0, d7
@NotTooRight:
    move.w  d7, (RAM_CurrSong)
    bsr     UpdateMenu                ; Update current song

    move.w  #28, (RAM_RArrowAnim)     ; Animate right arrow
    lea     (SFX_Beep), a0            ; Beep!
    bsr     Echo_PlaySFX
@NoRight:

    btst.l  #5, d0                  ; Play song?
    bne.s   @DoPlay
    btst.l  #6, d0
    beq.s   @NoPlay
@DoPlay:
    lea     (SongList), a1            ; Get song address
    move.w  (RAM_CurrSong), d7
    lsl.w   #4, d7
    lea     (a1,d7.w), a1
    move.l  (a1), a0
    bsr     Echo_PlayBGM              ; Play song
@NoPlay:

    btst.l  #4, d0                  ; Stop song?
    beq.s   @NoStop
    bsr     Echo_StopBGM
@NoStop:

    btst.l  #7, d0                  ; Debug key
    beq.s   @NoDebug
    lea     (BGM_Test), a0            ; Play test BGM
    ;bsr     Echo_PlayBGM
    lea     (SFX_Test), a0            ; Play test SFX
    bsr     Echo_PlaySFX
@NoDebug:

    lea     (@ArrowPal), a0

    move.w  (RAM_LArrowAnim), d0    ; Animate left arrow
    move.l  (a0,d0.w), d1
    move.l  #$C0060000, ($C00004)
    move.l  d1, ($C00000)
    subq.w  #2, d0
    bge.s   @NoLArrowOver
    moveq   #0, d0
@NoLArrowOver:
    move.w  d0, (RAM_LArrowAnim)

    move.w  (RAM_RArrowAnim), d0    ; Animate right arrow
    move.l  (a0,d0.w), d1
    move.l  #$C0260000, ($C00004)
    move.l  d1, ($C00000)
    subq.w  #2, d0
    bge.s   @NoRArrowOver
    moveq   #0, d0
@NoRArrowOver:
    move.w  d0, (RAM_RArrowAnim)

    move.w  (RAM_BGAnim), d0        ; Animate background
    bchg.l  #1, d0
    move.w  d0, (RAM_BGAnim)
    move.w  d0, ($C00004)

    bsr     VSync                   ; Next frame
    bsr     ReadJoypad
    bra     @MainLoop

;****************************************************************************

@ArrowPal:
    dc.w    $00E, $00E, $02E, $02E, $04E, $04E, $06E, $06E
    dc.w    $28E, $28E, $4AE, $4AE, $6CE, $6CE, $8EE, $8EE

;****************************************************************************
; UpdateMenu
; Shows the current option on screen
;****************************************************************************

UpdateMenu:
    bsr     ClearLines              ; Clear lines

    lea     (SongList), a1          ; Get address of song data
    move.w  (RAM_CurrSong), d0
    lsl.w   #4, d0
    lea     (a1,d0.w), a1
    addq.l  #4, a1

    moveq   #7, d0                  ; Write song title
    moveq   #9, d1
    move.w  #$A000, d2
    move.l  (a1)+, a0
    bsr     WriteString

    addq.w  #2, d1                  ; Write song description
    move.w  #$C000, d2
    move.l  (a1)+, a0
    bsr     WriteString
    addq.w  #2, d1
    move.l  (a1)+, a0
    bsr     WriteString

    rts                             ; End of subroutine