! Copyright (C) 2015 Sankaranarayanan Viswanathan.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors assocs calendar combinators
combinators.short-circuit destructors formatting fry kernel math
math.vectors namespaces opengl opengl.textures sequences sets
snake-game.game snake-game.sprites timers ui ui.gadgets
ui.gadgets.worlds ui.gestures ui.render ;

IN: snake-game.ui

SYMBOL: game-textures

TUPLE: snake-gadget < gadget
    snake-game timer textures ;

: start-new-game ( snake-gadget -- )
    <snake-game> >>snake-game drop ;

: <snake-gadget> ( -- snake-gadget )
    snake-gadget new [ start-new-game ] keep ;

CONSTANT: snake-game-cell-size 20

: game-loc>screen-loc ( loc -- loc )
    [ snake-game-cell-size * ] map ;

: lookup-texture ( key -- texture )
    game-textures get at ;

: draw-sprite* ( key screen-loc -- )
    [ lookup-texture draw-texture ] with-translation ;

: draw-sprite ( grid-loc key -- )
    swap game-loc>screen-loc draw-sprite* ;

: draw-food ( loc -- )
    "food" draw-sprite ;

: draw-background ( -- )
    { 0 0 } "background" draw-sprite ;

: draw-snake-head ( loc facing-dir -- )
    dup name>> rest "head-" prepend [
        [ game-loc>screen-loc ] dip {
            { :right [ { -20 -10 } ] }
            { :down  [ { -10 -20 } ] }
            { :up    [ { -10  0  } ] }
            { :left  [ {  0  -10 } ] }
        } case v+
    ] dip swap draw-sprite* ;

: draw-snake-body ( loc from-dir to-dir -- )
    [ name>> rest ] bi@ "body-%s-%s" sprintf draw-sprite ;

: draw-snake-tail ( loc facing-dir -- )
    name>> rest "tail-" prepend draw-sprite ;

: draw-snake-part ( loc from-dir snake-part -- )
    dup type>> {
        { :head [ drop opposite-dir draw-snake-head ] }
        { :body [ dir>> draw-snake-body ] }
        { :tail [ drop draw-snake-tail ] }
    } case ;

: next-snake-loc-from-dir ( loc from-dir snake-part -- new-loc new-from-dir )
    nip dir>> [ move-loc ] keep ;

: draw-snake ( loc from-dir snake -- )
    3dup [
        [ draw-snake-part ]
        [ next-snake-loc-from-dir ] 3bi
    ] each 2drop
    ! make sure to draw the head again
    first draw-snake-part ;

: game-status ( snake-game -- str )
    [ score>> ]
    [
        {
            { [ dup game-over?>> ] [ drop "Game Over" ] }
            { [ dup paused?>> ] [ drop "Game Paused" ] }
            [ drop "Game In Progress" ]
        } cond
    ] bi "Score: %d -- %s" sprintf ;

: update-status ( gadget -- )
    [ snake-game>> game-status ] keep show-status ;

: do-updates ( gadget -- )
    [ snake-game>> do-game-step ]
    [ update-status ]
    [ relayout-1 ]
    tri ;

: toggle-game-pause ( snake-gadget -- )
    snake-game>> [ not ] change-paused? drop ;

: load-game-textures ( snake-gadget -- textures )
    dup textures>> [ ] [ snake-textures >>textures textures>> ] ?if ;

M: snake-gadget graft*
    [ '[ _ do-updates ] 200 milliseconds every ] keep timer<< ;

M: snake-gadget ungraft*
    [ stop-timer f ] change-timer
    [ values dispose-each f ] change-textures
    drop ;

M: snake-gadget pref-dim*
    drop snake-game-dim [ snake-game-cell-size * 20 + ] map ;

M: snake-gadget draw-gadget*
    [ load-game-textures game-textures ] keep '[
        draw-background
        { 10 10 } [
            _ snake-game>>
            [ food-loc>> [ draw-food ] when* ]
            [
                [ snake-loc>> ]
                [ snake-dir>> opposite-dir ]
                [ snake>> ]
                tri draw-snake
            ] bi
        ] with-translation
    ] with-variable ;

: key-dir ( key -- dir )
    H{
        { "RIGHT"  :right }
        { "LEFT"   :left }
        { "UP"     :up }
        { "DOWN"   :down }
    } at ;

: quit-key? ( key -- ? )
    HS{ "ESC" "q" "Q" } in? ;

: pause-key? ( key -- ? )
    HS{ " " "SPACE" "p" "P" } in? ;

: new-game-key? ( key -- ? )
    HS{ "ENTER" "RET" "n" "N" } in? ;

M: snake-gadget handle-gesture
    swap dup key-down? [
        sym>> {
            { [ dup quit-key? ] [ drop close-window ] }
            { [ dup pause-key? ] [ drop toggle-game-pause ] }
            { [ dup new-game-key? ] [ drop start-new-game ] }
            [
                key-dir [
                    swap snake-game>> dup {
                        [ game-in-progress? ]
                        [ snake-dir>> opposite-dir pick = not ]
                    } 1&& [ next-turn-dir<< ] [ 2drop ] if
                ] [ drop ] if*
            ]
        } cond
    ] [ 2drop ] if f ;