; multi-segment executable file template.

data segment
    name_contents db "c:\contents.bin", 0

    string_menu_1 db "- Import Spreadsheet";length=20
    string_menu_2 db "- Show spreadsheet"  ;length=18
    string_menu_3 db "- Edit spreadsheet"  ;length=18
    string_menu_4 db "- Export spreadsheet";length=20
    string_menu_5 db "- About"             ;length=7
    string_menu_6 db "- Exit"              ;length=6

    string_formula db "Formula"
    string_result db "Result"
    string_menu db "Menu"

    str_buffer db 7, dup(0)

    num_hcell dw 04h
    matrix_lenght dw 160 ;estava 240 antes
    matrix_height dw 65
    cell db 16 dup(-128)
    ;formula_lenght 88
ends

stack segment
    dw   128  dup(0)
ends

code segment
start:
; set segment registers:
    mov ax, data
    mov ds, ax
    mov es, ax

    ;open contents.bin
        call open_contents

    draw_menu:
    ;iniciate video mode
        mov ah, 00h
        mov al, 13h
        int 10h

        call menu

        keep_checking_menu:
            mov ax, 03h
            int 33h
            shr cx, 1  ; x/2 - in this mode the value of CX is doubled.
            cmp bx, 1
            jnz keep_checking_menu

        call checkMenu

        cmp dh, 01h
        jne draw_menu


    ;saves contents.bin
        call save_contents

    mov ax, 4c00h ; exit to operating system.
    int 21h

;*****************************************************************
; menu -
; descricao: draws menu
; input -
; output -
; destroi -
;*****************************************************************

    menu proc
        xor dh, dh
        mov al, 01h
        mov bh, 00h
        mov bl, 0Fh
        mov dl, 02h

        mov cx, 14h;length of string_1
        mov bp, offset string_menu_1

        imprime_string:
            inc dh
            inc dh ;next line
            push bx

            xor bh, bh
            mov ah, 13h
            int 10h

            pop bx
            inc bh ;next string

        cmp bh, 02h
        je menu_2

        cmp bh, 03h
        je menu_3

        cmp bh, 04h
        je menu_4

        cmp bh, 05h
        je menu_5
        ja end_of_menu

        mov cx, 12h
        mov bp, offset string_menu_2
        jmp imprime_string

        menu_2:
        mov bp, offset string_menu_3
        jmp imprime_string

        menu_3:
        mov cx, 14h
        mov bp, offset string_menu_4
        jmp imprime_string

        menu_4:
        mov cx, 07h
        mov bp, offset string_menu_5
        jmp imprime_string

        menu_5:
        mov cx, 06h
        mov bp, offset string_menu_6
        jmp imprime_string

        end_of_menu:
        ret
    menu endp

;*****************************************************************
; checkMenu -
; descricao: checks position clicked on menu window
; input -
; output -
; destroi -
;*****************************************************************

        checkMenu proc
            xor dh, dh

            cmp cx, 13h          ;left limit  x
            jb done_checking_menu
            cmp cx, 178          ;right limit x
            ja done_checking_menu
            cmp dx, 12h          ;superior limit y
            jb done_checking_menu
            cmp dx, 6Ch          ;inferior limit y
            ja done_checking_menu

            cmp dx, 1Bh          ;test import
            ja test_show
            call import_spreadsheet
            jmp done_checking_menu

            test_show:
            cmp dx, 2Bh
            ja test_edit
            call show_spreadsheet
            jmp done_checking_menu

            test_edit:
            cmp dx, 3Bh
            ja test_export
            call edit_spreadsheet
            jmp done_checking_menu

            test_export:
            cmp dx, 4Bh
            ja test_about
            call export_spreadsheet
            jmp done_checking_menu

            test_about:
            cmp dx, 5Bh
            ja definitely_exit
            call show_about
            jmp done_checking_menu

            definitely_exit:
            mov dh, 01h

            done_checking_menu:
            ret
        checkMenu endp

;*****************************************************************
; import_spreadsheet -
; descricao: importa um ficheiro .txt
; input -
; output -
; destroi -
;*****************************************************************

        import_spreadsheet proc
            ret
        import_spreadsheet endp

;*****************************************************************
; show_spreadsheet -
; descricao: mostra a spreadsheet em memoria
; input -
; output -
; destroi -
;*****************************************************************

        show_spreadsheet proc
            ;reiniciate video mode to clear window
            mov ah, 00h
            mov al, 13h
            int 10h

            ret
        show_spreadsheet endp

;*****************************************************************
; edit_spreadsheet -
; descricao: mostre e permite editar a spreadsheet em memoria
; input -
; output -
; destroi -
;*****************************************************************

        edit_spreadsheet proc
            ;reiniciate video mode to clear window
            mov ah, 00h
            mov al, 13h
            int 10h

            ;draw spreadsheet
            call createMatrix

            call createMenuBox

            call createFormulaBox

            call createResultBox

            call showLetters

            call showNumbers

            mov ax, 00h
            int 33h

            ;wait for user input
            keep_checking:
                mov ax, 03h
                int 33h
                shr cx, 1       ; x/2 - in this mode the value of CX is doubled.
                cmp bx, 1
                jnz keep_checking

            call cANDeCell  ;check and evaluate cell

            ;Preisamos agora de uma funcao para avaliar a celula que foi clicada
            ;ja temos toda a informacao necessaria
            ;devo meter AL para a dizer se a celula e valida
            ;e AH para dizer o tipo de celula

            cmp bx, 1     ;exit to MENU
            jne keep_checking

            ret
        edit_spreadsheet endp

;*****************************************************************
; export_spreadsheet -
; descricao: exporta para um ficheiro .txt a funcao em memoria
; input -
; output -
; destroi -
;*****************************************************************

        export_spreadsheet proc
            ret
        export_spreadsheet endp

;*****************************************************************
; show_about -
; descricao: mostra certas informacoes sobre os criadores
; input -
; output -
; destroi -
;*****************************************************************

        show_about proc
            ;reiniciate video mode to clear window
            mov ah, 00h
            mov al, 13h
            int 10h

            ret
        show_about endp

;*****************************************************************
; hLine -
; descricao: creates horizontal lines for the matrix
; input - bx= numero de linhas ; cx = horizontal margin ; dx = vertical margin ; ax = line lenght
; output -
; destroi -
;*****************************************************************

    hLine proc

        n_hlines:
            push ax
            push cx

            h_change_pixel:
            push ax
            mov ah, 0Ch
            mov al, 0Fh
            int 10h

            pop ax
            dec ax
            jz h_done
            inc cx
            jmp h_change_pixel

        h_done:
        pop cx
        pop ax
        add dx, 16
        dec bx
        jnz n_hlines

        ret
    hLine endp


;*****************************************************************
; vLine -
; descricao: creates vertical lines for the matrix
; input - bx= numero de linhas ; cx = horizontal margin ; dx = vertical margin ; ax = matrix_height
; output -
; destroi -
;*****************************************************************

    vLine proc

        n_vlines:
            push ax
            push dx

            v_change_pixel:
            push ax
            mov ah, 0Ch
            mov al, 0Fh
            int 10h

            pop ax
            dec ax
            jz v_done
            inc dx
            jmp v_change_pixel

        v_done:
        pop dx
        pop ax
        add cx, 40
        dec bx
        jnz n_vlines

        ret
    vLine endp



;*****************************************************************
; createMatrix -
; descricao: creates horizontal lines for the matrix
; input - bx= numero de linhas ; cx = horizontal margin ; dx = vertical margin ; ax = line lenght
; output -
; destroi -
;*****************************************************************

  createMatrix proc
    mov bx, 05h ; se calhar temos de remover isto
    mov dx, 28
    mov cx, 20
    mov ax, matrix_lenght
    call hLine

    mov bx, 05h
    mov cx, 20
    mov dx, 28
    mov ax, matrix_height
    call vLine

    ret

  createMatrix endp

;*****************************************************************
; createMatrix -
; descricao: creates horizontal lines for the matrix
; input - bx= numero de linhas ; cx = horizontal margin ; dx = vertical margin ; ax = line lenght
; output -
; destroi -
;*****************************************************************


  createMenuBox proc

    mov bx, 2
    mov ax, 40
    mov cx, 20
    mov dx, 156
    call hLine

    mov bx, 2
    mov ax, 17
    mov cx, 20
    mov dx, 156
    call vLine

    ;writes "Menu" inside the cell
        mov al, 1
        mov bl, 0Fh
        mov cx, 4    ;string lenght
        mov dh, 20
        mov dl, 3
        mov ah, 13h
        mov bp, offset string_menu
        int 10h

  ret

  createMenuBox endp

;*****************************************************************
; createFormulaBox -
; descricao: creates a box where the user will input operations
; input -
; output -
; destroi -
;*****************************************************************

    createFormulaBox proc ;Provavelmente vamos ter de alterar o
                          ;tamanho da caixa da formula

        mov ax, 80 ; formula lenght
        mov cx, 20
        mov dx, 124
        mov bx, 02h
        call hLine

        mov ax, 17 ; formula height + 1
        mov cx, 20
        mov dx, 124
        mov bx, 01h
        call vLine

        mov ax, 17 ; formula height + 1
        mov cx, 100
        mov dx, 124
        mov bx, 01h
        call vLine

    ret

    createFormulaBox endp


;*****************************************************************
; createResultBox -
; descricao: creates a box to output the result
; input -
; output -
; destroi -
;*****************************************************************

    createResultBox proc

        mov ax, 80 ;cell lenght
        mov cx, 140
        mov dx, 124
        mov bx, 02h
        call hLine

        mov ax, 17 ; formula height + 1
        mov cx, 140
        mov dx, 124
        mov bx, 01h
        call vLine

        mov ax, 17 ; formula height + 1
        mov cx, 220
        mov dx, 124
        mov bx, 01h
        call vLine

    ret

    createResultBox endp

;*****************************************************************
; showLetter -
; descricao: prints a letter for each matrix collumn,
;            also prints "Formula" and "Result"
; input -
; output -
; destroi -
;*****************************************************************

    showLetters proc

        xor bh, bh
        mov bl, 0Fh
        mov cx, 1
        mov dl, 04
        mov al, 'A'

        new_letter:
            ;set cursor position
            mov dh, 02h
            mov ah, 02h
            int 10h

            ;write char at cursor position
            mov ah, 09h
            int 10h

            inc al
            add dl, 5
            cmp al, 'E'
            jnz new_letter

        ;writes "Formula" above the big cell
        mov al, 1
        mov bl, 0Fh
        mov cx, 7    ;string lenght
        mov dh, 14
        mov dl, 3
        mov ah, 13h
        mov bp, offset string_formula
        int 10h

        ;writes "Result" aove the small cell
        mov dl, 18
        mov cx, 6   ;string lenght deve ser 6
        mov bp, offset string_result
        int 10h

    ret

    showLetters endp

;*****************************************************************
; showNumbers -
; descricao: prints a number for each matrix row
; input -
; output -
; destroi -
;*****************************************************************

    showNumbers proc

        xor bh, bh
        mov bl, 0Fh
        mov cx, 1
        mov dh, 04h
        mov al, '1'

        new_number:
        ;set cursor position
        mov dl, 01h
        mov ah, 02h
        int 10h

        ;write char at cursor position
        mov ah, 09h
        int 10h

        inc al
        add dh, 2
        cmp al, '5'
        jnz new_number

    ret

    showNumbers endp



;*****************************************************************
; checkCell -
; descricao: checks and eveluates what to do with the cell clicked by the user
; input -
; output - bx=0(exit to menu)
; destroi -
;*****************************************************************

    cANDeCell proc

        xor bx, bx ;nao sei se isto e preciso, tem a ver com um racicionio que ja nao me lembro

        ;check if user clicked on the margin

        cmp cx, 20
        jb done_checking
        cmp dx, 28
        jb done_checking

        mov ax, cx
        sub ax, 20

        mov bx, 40
        div bl
        xor ah, ah ;sabemos agora a celula das letras
        mov cx, ax ;o resultado esta em cx

        mov ax, dx
        sub ax, 28

        mov bx, 16
        div bl
        xor ah, ah
        mov dx, ax ;coordonates are now stored in cx(x) and dx(y)

        ;check if user clicked on a matrix cell

        cmp cx, 3
        ja not_matrix
        cmp dx, 3
        ja not_matrix
        call matrixCellClicked    ;a celula clicada foi uma da matriz descrita por cx e dx
        jmp done_checking

        ;check if user clicked on the formula or result cell
        not_matrix:
        cmp dx, 6
        jnz not_fORr
        cmp cx, 1
        ja not_formula
        ;a celula clicada e a celula da formula
        jmp done_checking

        not_formula:
        cmp cx, 3
        jnz not_fORr
        cmp cx, 4
        jnz not_fORr
        ;a celula clicada e a celula do resultado
        jmp done_checking

        not_fORr:
        ;check if used clicked on MENU
        cmp dx, 8 ;esta na linha do menu
        jnz done_checking
        cmp cx, 0
        jnz done_checking
        mov bx, 1
        done_checking:

    ret
    cANDeCell endp


;*****************************************************************
; matrixCellClicked -
; descricao: edit clicked cell
; input -
; output -
; destroi -
;*****************************************************************

    matrixCellClicked proc

        ;meter o cursor no sitio certo
        push cx
        push dx

        mov al, 05h  ;multiplo necessario
        mul cl       ;multiplicar a celula pelo multiplo de posicao
        add al, 03h  ;somar a constante de deslocamento incial
        mov bl, al   ;adquirir a posicao em x do cursor

        mov al, 02h  ;a mesma coisa mas para o
        mul dl       ;eixo do y
        add al, 04h

        mov dl, bl   ;from cx
        mov dh, al   ;from dx

        push dx

        xor bx, bx

        mov ah, 02h
        int 10h

        mov ch, 06h
     	mov cl, 0000_1111b
     	mov ah, 01h
     	int 10h

        ;modificacoes comecam aqui
        mov dx, offset str_buffer
        mov ah, 0Ah
        int 21h

        ;se o buffer estiver todo cheio entao o utilizador meteu mal os numeros
        ;falta fazer essa comparacao

        pop dx

        call evaluateInput ;ficamos com o valor em decimal no registo bx

        pop dx
        pop cx

        push bx
        xor bx, bx
        mov al, 4
        mul cl

        mov bl, al
        add bx, dx
        pop cx
        mov cell[bx], cl

    ret
    matrixCellClicked endp


;*****************************************************************
; evaluateInput -
; descricao: checks if input is valid, startes checking from the last number
; input -  DL,DH = column, row at which to start writing
; output -
; destroi -
;*****************************************************************

    evaluateInput proc

        xor bx, bx
        mov bl, str_buffer[1]
        ;mov buffer[bx + 2], '$'
        cmp bl, 4
        ja invalid_input
        mov si, bx

        check_input:
            dec si
            cmp si, -1
            jz input_checked
            cmp si, 0
            jnz check_char
            cmp ch, '-'
            jz negative_num
            mov ax, 0

        check_char:
            mov ch, str_buffer[si + 2]
            cmp ch, '0'
            jb invalid_input
            cmp ch, '9'
            ja invalid_input
            jmp check_input

        negative_num:
            mov ax, 1
        input_checked:
            ;push ax
            ;mov al, 1
            ;xor bh, bh
            ;mov cx, bx  ;string lenght was in bl
            ;mov bl, 0Fh
            ;mov bp, offset str_buffer
            ;add bp, 2
            ;int 10h

            ;pop ax
            call asciiToDecimal ;ficamos com o valor em decimal no registo bx

        invalid_input:
        ret

    evaluateInput endp


;*****************************************************************
; asciiToDecimal -
; descricao:
; input - ax = 1 if number is negative, ax = 0 if number is positive
; output - bx = numero para guardar
; destroi -
;*****************************************************************

    asciiToDecimal proc

        push ax
        xor ax, ax
        xor bx, bx
        xor ch, ch
        mov cl, str_buffer[1]
        mov si, cx
        mov al, 1
        mov dl, 10
        next_number:
        dec si
        cmp si, 0
        jz last_char
        push ax   ;isto deve dar erro porque eu acho que so queria al
        mov dh, str_buffer[si + 2]
        sub dh, '0'
        mul dh
        add bx, ax  ;o numero esta no bx

        pop ax
        mul dl

        jmp next_number
        last_char:
        pop cx
        cmp cx, 1 ;verificar se o numero e negativo ou nao
        jnz pos_num
        neg bx
        jmp ascii_dec_done:
        pos_num:
        ;mul dl ;para meter o ax com o multiplo correcto
        mov dh, str_buffer[2]
        sub dh, '0'
        mul dh
        add bx, ax

        ascii_dec_done:
        ret
    asciiToDecimal endp

;*****************************************************************
; fopen -
; descricao: abre um ficheiro em modo read(al==0), write(al==1) ou append(al==2)
; input - dx=offset nome ficheiro
; output - ax=file_handle
; destroi -
;*****************************************************************

    fopen proc
		mov ah, 3Dh
		mov al, 02h
		mov cx, 00h
		int 21h

        ret
    fopen endp

;*****************************************************************
; fclose -
; descricao:
; input - bx= file handle
; output -
; destroi -
;*****************************************************************

    fclose proc
		mov ah, 3Eh
		int 21h

        ret
    fclose endp

;*****************************************************************
; fcreate -
; descricao: cria um ficheiro
; input - dx=offset nome ficheiro
; output - ax=file_handle
; destroi -
;*****************************************************************

    fcreate proc
		mov ah, 3Ch
		mov cx, 00h
		int 21h

        ret
    fcreate endp

;*****************************************************************
; save_contents -
; descricao: saves contents.bin or creates it
; input -
; output -
; destroi -
;*****************************************************************

    save_contents proc
        ;tries to open file
        mov dx, offset name_contents
        call fopen
        jnc save

        ;in case it doesn't exist, creates it
        call fcreate

        save:
        mov bx, ax ;move handle

        mov cx, 16 ;number of bytes
        mov dx, offset cell ;offset to write to
        mov ah, 40h
        int 21h

        ;closes file
        call fclose

        ret
    save_contents endp

;*****************************************************************
; open_contents -
; descricao: opens contents.bin if it exists
; input -
; output -
; destroi - tudo
;*****************************************************************

    open_contents proc
        ;tries to open file
        mov dx, offset name_contents
        call fopen
        jc end_open_cont ;in case it doesn't exist yet

        mov bx, ax

        mov cx, 16 ;number of bytes
        mov dx, offset cell ;offset to write to
        mov ah, 3Fh
        int 21h

        call fclose
        end_open_cont:
        ret
    open_contents endp

ends

end start ; set entry point and stop the assembler.