showPage:
    xor a
    ld (show_offset), a
    ld a, 1
    ld (cursor_pos), a
    call renderScreen
    call showCursor
showLp:
    call controls
    dup 5
    halt
    edup
    jr showLp

controls:
    call inkey
    
    cp 0
    ret z 

    cp 'q'
    jr z, pageCursorUp

    cp 'a'
    jr z, pageCursorDown

    cp 13
    jp z, selectItem 

    cp 'b'
    jr z, historyBack

    cp 'o'
    jp z, openURI
    ret

historyBack:
    ld hl, server
    ld de, path
    ld bc, port
    call openPage
    jp showPage

pageCursorUp:
    ld a, (cursor_pos)
    dec a 
    cp 0
    jp z, pageScrollUp

    push af
    call hideCursor
    pop af
    ld (cursor_pos), a
    call showCursor
    ret

pageCursorDown:
    ld a, (cursor_pos)
    inc a
    cp 21
    jp z, pageScrollDn

    push af
    call hideCursor
    pop af
    ld (cursor_pos), a
    call showCursor
    ret

pageScrollDn:
    ld hl, (show_offset)
    ld de, 20
    add hl, de
    ld (show_offset), hl
    ld a, 1
    ld (cursor_pos), a
    call renderScreen
    call showCursor
    ret 

pageScrollUp:
    ld a, (show_offset)
    and a
    ret z

    ld hl, (show_offset)
    ld de, 20
    sub hl, de
    ld (show_offset), hl

    ld a, 20
    ld (cursor_pos), a
    call renderScreen
    call showCursor
    ret

selectItem:
    ld a, (cursor_pos)
    dec a
    ld b, a
    ld a, (show_offset)
    add b 
    ld b, a
    call findLine
    ld a, h
    cp l
    ret z
    ld a, (hl)

    cp '1'
    jr z, downPg

    cp '0'
    jr z, downPg

    cp '9'
    jp z, downFl

    cp '7'
    jr z, userInput

    ret  

userInput:
    call cleanIBuff
    call input

    call extractInfo
    ld hl, file_buffer
    call findEnd
    ld a, 9
    ld (hl), a
    inc hl
    ex hl, de
    ld hl, iBuff
    ld bc, 64
    ldir

    ld hl, hist
    ld de, path
    ld bc, 322
    ldir

    ld hl, server_buffer
    ld de, file_buffer
    ld bc, port_buffer
    call openPage
    jp showPage

downPg:
    push af
    call extractInfo

    ld hl, hist
    ld de, path
    ld bc, 322
    ldir

    ld hl, server_buffer
    ld de, file_buffer
    ld bc, port_buffer
    call openPage
    pop af

    cp '1'
    jp z,showPage

    cp '0'
    jp z, showText

    ret

downFl:
    call extractInfo

    call cleanIBuff
    ld hl, file_buffer
    call findFnme
    jp isImage
dfl:
    ld hl, file_buffer
    call findFnme
    ld de, iBuff
    ld bc, 65
    ldir
    
    call input
    ld hl, server_buffer
    ld de, file_buffer
    ld bc, port_buffer
    call makeRequest
    
    ld hl, iBuff
    call downloadData
    call showCursor
    ret

isImage:
	ld a, (hl)
	and a
	jr z, checkImg
	push hl
	call pushRing
	pop hl
	inc hl
	jr isImage
imgExt	db ".scr", 0
imgExt2 db ".SCR", 0
checkImg:
	ld hl, imgExt
	call searchRing
	cp 1
	jr z, loadImage

	ld hl, imgExt2
	call searchRing
	cp 1
	jr z, loadImage
	jp dfl
loadImage:
	ld hl, server_buffer
	ld de, file_buffer
	ld bc, port_buffer
	call makeRequest
	ld hl, #4000
	call loadData

    ld c, #ff
    xor a
    out (c), a
wKey:	call inkey
	or a
	jr z, wKey
	jp showPage
   
findFnme:
    push hl
    pop de
ffnmlp:
    ld a, (hl)
    
    cp 0
    jr z, ffnmend

    cp '/'
    jr z, fslsh

    inc hl
    jp ffnmlp
fslsh:
    inc hl
    push hl
    pop de
    jp ffnmlp
ffnmend:
    push de
    pop hl
    ret

showType:
    ld a, (cursor_pos)
    dec a
    ld b, a
    ld a, (show_offset)
    add b 
    ld b, a
    call findLine
    ld a, h
    cp l
    jr z, showTypeUnknown

    ld a, (hl)
    
    cp 'i'
    jr z, showTypeInfo

    cp '9'
    jr z, showTypeDown

    cp '1'
    jr z, showTypePage

    cp '0'
    jr z, showTypeText

    cp '7'
    jr z, showTypeInput

    jr showTypeUnknown

showTypeInput:
    ld hl, type_inpt
    call showTypePrint
    call showURI
    ret

showTypeText:
    ld hl, type_text
    call showTypePrint
    call showURI
    ret

showTypeInfo:
    ld hl, type_info
    jp showTypePrint

showTypePage:
    ld hl, type_page
    call showTypePrint
    call showURI
    ret

showTypeDown:
    ld hl, type_down
    call showTypePrint
    call showURI
    ret

showURI:
    call extractInfo
    ld hl, server_buffer
    call printZ64
    
    ld hl, file_buffer
    call printZ64
    ret
showTypeUnknown:
    ld hl, type_unkn
    jp showTypePrint

showTypePrint:
    push hl
    
    ld b, 21
    ld c, 0
    call gotoXY
    ld hl, cleanLine
    call printZ64
    
    ld b, 21
    ld c, 0
    call gotoXY
    pop hl
    call printZ64
    ret

renderHeader:
    call clearScreen
    ld bc, 0
    call gotoXY

    ld hl, head
    call printZ64
    
    ld d, 0
    call inverseLine

    ret

renderScreen:
    call renderHeader
    ld b, 20
renderLp:
    push bc
    ld a, 20
    sub b
    ld b, a
    ld a, (show_offset)
    add b
    ld b, a 
    call renderLine
    pop bc
    djnz renderLp
    ret

; b - line number
renderLine:
    call findLine
    
    ld a, h
    or l 
    ret z 

    ld a, (hl)
    and a
    ret z 
    inc hl
    call printT64
    call mvCR
    ret

; B - line number
; HL - pointer to line(or zero if doesn't find it)
findLine:
    ld hl, page_buffer
fndLnLp:
    ld a, b
    and a
    ret z 

    ld a, (hl)
    
    and a           ; Buffer ends?
    jr z, fndEnd
    
    cp 10           ; New line?
    jr z, fndLnNL
    inc hl
    jp fndLnLp

fndLnNL:
    dec b
    inc hl
    jp fndLnLp
fndEnd:
    ld hl, 0
    ret

extractInfo:
    ld a, (cursor_pos)
    dec a
    ld b, a
    ld a, (show_offset)
    add b 
    ld b, a
    call findLine
    ld a, h
    cp l
    ret z

    call findNextBlock
    inc hl
    ld de, file_buffer
    call extractCol
    inc hl
    ld de, server_buffer
    call extractCol
    inc hl
    ld de, port_buffer
    call extractCol
    ret

extractCol:
    ld a, (hl)

    cp 0
    jr z, endExtract

    cp 09
    jr z, endExtract

    cp 13
    jr z, endExtract

    ld (de), a
    inc de
    inc hl
    jr extractCol

endExtract:
    xor a
    ld (de), a
    ret

findNextBlock:
    ld a, (hl)

    cp 09   ; TAB
    ret z
    
    cp 13   ; New line
    ret z

    cp 0    ; End buffer
    ret z

    inc hl
    jp findNextBlock

show_offset     db  0
    display $
cursor_pos      db  1

head      db "  UGophy - ZX-UNO Gopher client v. 0.5 (c) Alexander Sharikhin", 13,0

cleanLine db "                                                                ",0

type_inpt db "User input: ", 0
type_text db "Text file: ", 0
type_info db "Information ", 0
type_page db "Page: ", 0
type_down db "File to download: ", 0
type_unkn db "Unknown type ", 0 

    display $

file_buffer defs 255     ; URI path
server_buffer defs 70   ; Host name
port_buffer defs 7      ; Port

end_inf_buff equ $