get "libhdr"

static $( randstate = 0 $)

manifest $(
    nummask  = #XF
    flagmask = #X10
    bombmask = #X20
    revealed = #X40
    MAXINT = (~0)>>1
    MININT = ~MAXINT
$)

let min(x,y) = x<y -> x, y
and max(x,y) = x>y -> x, y

let rand() = valof
$(  randstate := random(randstate)
    resultis randstate >> 7
$)

let randto(x) = valof
$(  let r, mask = ?, 1
    while mask<x do mask := (mask << 1) | 1
    r := rand() & mask repeatuntil r < x
    resultis r
$)

// Place a bomb on the field (if not already a bomb)
let placebomb(field, xsize, ysize, x, y) =
    (field!(y*xsize+x) & bombmask) ~= 0 -> false,
    valof
$(  for xa = max(x-1, 0) to min(x+1, xsize-1)
        for ya = max(y-1, 0) to min(y+1, ysize-1)
        $(  let loc = ya*xsize+xa
            let n = field!loc & nummask
            field!loc := (field!loc & ~nummask) | (n + 1)
        $)
    field!(y*xsize+x) := field!(y*xsize+x) | bombmask
    resultis true
$)

// Populate the field with N bombs
let populate(field, xsize, ysize, nbombs) be
$(  for i=0 to xsize*ysize-1 do field!i := 0
    while nbombs > 0
    $(  let x, y = randto(xsize), randto(ysize)
        if placebomb(field, xsize, ysize, x, y) then
            nbombs := nbombs - 1
    $)
$)

// Reveal field (X,Y) - returns true if stepped on a bomb
let reveal(field, xsize, ysize, x, y) =
    (field!(y*xsize+x) & bombmask) ~= 0 -> true,
    valof
$(  let loc = y*xsize+x
    field!loc := field!loc | revealed
    if (field!loc & nummask) = 0 then
        for xa = max(x-1, 0) to min(x+1, xsize-1)
            for ya = max(y-1, 0) to min(y+1, ysize-1)
                if (field!(ya*xsize+xa) &
                        (bombmask | flagmask | revealed)) = 0 do
                    reveal(field, xsize, ysize, xa, ya)
    resultis false
$)

// Toggle flag
let toggleflag(field, xsize, ysize, x, y) be
$(  let loc = y*xsize+x
    field!loc := field!loc neqv flagmask
$)

// Show the field. Returns true if won.
let showfield(field, xsize, ysize, kaboom) = valof
$(  let bombs, flags, hidden, found = 0, 0, 0, 0
    for i=0 to xsize*ysize-1
    $(  if (field!i & revealed) = 0 do hidden := hidden + 1
        unless (field!i & bombmask) = 0 do bombs := bombs + 1
        unless (field!i & flagmask) = 0 do flags := flags + 1
        if (field!i & bombmask) ~= 0 & (field!i & flagmask) ~= 0
            do found := found + 1
    $)
    writef("Bombs: %N - Flagged: %N - Hidden: %N*N", bombs, flags, hidden)
    wrch('+')
    for x=0 to xsize-1 do wrch('-')
    writes("+*N")
    for y=0 to ysize-1
    $(  wrch('|')
        for x=0 to xsize-1
        $(  let loc = y*xsize+x
            test kaboom & (field!loc & bombmask) ~= 0 do
                wrch('**')
            or test (field!loc & (flagmask | revealed)) = flagmask do
                wrch('?')
            or test (field!loc & revealed) = 0 do
                wrch('.')
            or test (field!loc & nummask) = 0 do
                wrch(' ')
            or
                wrch('0' + (field!loc & nummask))
        $)
        writes("|*N")
    $)
    wrch('+')
    for x=0 to xsize-1 do wrch('-')
    writes("+*N")
    resultis found = bombs
$)

// Ask a question, get number
let ask(q, min, max) = valof
$(  let n = ?
    $(  writes(q)
        n := readn()
    $) repeatuntil min <= n <= max
    resultis n
$)

// Read string
let reads(v) = valof
$(  let ch = ?
    v%0 := 0
    $(  ch := rdch()
        if ch = endstreamch then resultis false
        v%0 := v%0 + 1
        v%(v%0) := ch
    $) repeatuntil ch = '*N'
    resultis true
$)

// Play game given field
let play(field, xsize, ysize) be
$(  let x = ?
    let y = ?
    let ans = vec 80
    if showfield(field, xsize, ysize, false)
    $(  writes("*NYou win!*N")
        finish
    $)
    $(  writes("*NR)eveal, F)lag, Q)uit? ")
        unless reads(ans) finish
        unless ans%0 = 2 & ans%2='*N' loop
        ans%1 := ans%1 | 32
        if ans%1 = 'q' then finish
    $) repeatuntil ans%1='r' | ans%1='f'

    y := ask("Row? ", 1, ysize)-1
    x := ask("Column? ", 1, xsize)-1

    switchon ans%1 into
    $(  case 'r':
            unless (field!(y*xsize+x) & flagmask) = 0
            $(  writes("*NError: that field is flagged, unflag it first.*N")
                endcase
            $)
            unless (field!(y*xsize+x) & revealed) = 0
            $(  writes("*NError: that field is already revealed.*N")
                endcase
            $)
            if reveal(field, xsize, ysize, x, y)
            $(  writes("*N K A B O O M *N*N")
                showfield(field, xsize, ysize, true)
                finish
            $)
            endcase
        case 'f':
            test (field!(y*xsize+x) & revealed) = 0
               do toggleflag(field, xsize, ysize, x, y)
               or writes("*NError: that field is already revealed.*N")
            endcase
    $)
    wrch('*N')
$) repeat

let start() be
$(  let field, xsize, ysize, bombs = ?, ?, ?, ?

    writes("Minesweeper*N-----------*N*N")
    randstate := ask("Random seed? ", MININT, MAXINT)
    xsize := ask("Width (4-64)? ", 4, 64)
    ysize := ask("Height (4-22)? ", 4, 22)

    // 10 to 20% bombs
    bombs := muldiv(xsize,ysize,10) + randto(muldiv(xsize,ysize,10)+1)

    field := getvec(xsize*ysize)
    populate(field, xsize, ysize, bombs)
    play(field, xsize, ysize)
$)