-- demoscene (firehose): valley→stream→sky→night, bluesky events rain as particles

parts={}       -- firehose particle rain
shoot={}       -- shooting stars
stars={}       -- starfield (world space, high up)
birds={}       -- boids flock (screen space)
demo_t=0       -- loop clock (s)
df=0           -- frame counter (throttles the costly sun glow)
demo_likes=0   -- cumulative firehose tallies, ones place (persist across loops)
demo_posts=0
demo_lk=0      -- thousands place (16.16 fixed-point caps a single int at ~32767)
demo_pk=0
cycle=87       -- loop length (s)
demo_mb=0      -- prev mouse-button state
fire_t=0       -- time() of last real (nonzero) firehose event
demo_track=1   -- selected tune (persists across demo entries)
track_lbl=0    -- show the tune name until this time()
tunes={0,4,8,-1}                 -- music start patterns: gym,cdl,canon,off
tunenames=split"gymnopedie,clair de lune,canon in d,music off"

function lerp(a,b,t) return a+(b-a)*t end
function eio(t) return t*t*(3-2*t) end
function clmp(t) return mid(0,t,1) end
-- altitude 0 (ground) .. 1 (night), eased; drives the upward camera pan
function alt() return eio(clmp((demo_t-16)/34)) end
function camtop() return lerp(312,0,alt()) end
function fmtk(k,o)
 if k>0 then return k.."."..(o\100).."k" end
 return ""..o
end

-- carry ones>=1000 into thousands so totals never hit the fixed-point cap
function roll()
 if demo_likes>=1000 then demo_lk+=demo_likes\1000 demo_likes%=1000 end
 if demo_posts>=1000 then demo_pk+=demo_posts\1000 demo_posts%=1000 end
end

function play_tune()
 local m=tunes[demo_track]
 if m>=0 then music(m) else music(-1) end
 track_lbl=time()+2
end

-- pause-menu music (slot 1) + theme (slot 2); music is demo-only, synced via _update change-detect.
function music_label() return chr(141).." "..tunenames[demo_track] end -- 141=♪
function theme_label() return "theme: "..tc("day","night") end

function music_menu(b) -- ←=prev, →/🅾/❎=next; "music off" is part of the cycle
 if b&1>0 then demo_track=(demo_track+2)%4+1 else demo_track=demo_track%4+1 end
 if scr==scr_demo then play_tune() end -- audible only in the demo; elsewhere just arm it
 menuitem(nil,music_label()) return true
end
function theme_menu()
 theme=1-theme sfx(0) menuitem(nil,theme_label()) return true
end
-- feed switcher (slot 3): mutates active_feed; timeline reloads after menu closes.
function feed_label() return "feed: "..feedsm[active_feed] end
function feed_menu(b)
 if #feeds<2 then return true end
 if b&1>0 then active_feed=(active_feed-2+#feeds)%#feeds+1
 else active_feed=active_feed%#feeds+1 end
 sfx(0) menuitem(nil,feed_label()) return true
end

function enter_demo()
 scr=scr_demo
 demo_t=0 df=0
 parts={} shoot={}
 demo_likes=0 demo_posts=0 demo_lk=0 demo_pk=0 -- cumulative this session
 stars={}
 for _=1,40 do
  add(stars,{x=rnd(128),y=rnd(120),p=rnd(1)})
 end
 init_birds()
 build_lut()
 enqueue(op_req_demo)
 demo_mb=0
 fire_t=time()
 play_tune()
 track_lbl=time()+5  -- keep readable for ~2s after the 3s fade-in
end

function exit_demo()
 parts={}
 pal()
 music(-1)
 open_timeline(false)
 sfx(1)
end

function quit_demo()
 enqueue(op_req_demo_stop)
 exit_demo()
end

-- per-kind firehose particle: {y, vy base, vy*rnd range, colour}. kind 4 + kind-1 colour flip stay inline.
sd={{-4,.4,.5,8},{132,-.5,-.6,12},{132,-.4,-.5,11}}
function spawn(kind,n)
 -- stop spawning ~3s before credits vanish so particles drift off before the seam.
 if demo_t>=72 then return end
 local cap=alt()>0.8 and 14 or 46
 for _=1,min(n,4) do
  if #parts>=cap then return end
  local p={kind=kind,t=rnd(1),x=rnd(128)}
  if kind<4 then
   local d=sd[kind]
   p.y=d[1] p.vy=d[2]+d[3]*rnd(1) p.c=d[4]
   if kind==1 and rnd(1)<.5 then p.c=14 end
  else
   p.y=20+rnd(90) p.vy=-.2-rnd(.3) p.c=10
  end
  add(parts,p)
 end
end

function on_fire(po,li,re,fo,de)
 if po+li+re+fo>0 then fire_t=time() end
 demo_likes+=li demo_posts+=po roll()
 spawn(1,li) spawn(2,po) spawn(3,re) spawn(4,fo)
 for _=1,min(de,4) do
  if #parts>0 then deli(parts,1) end
 end
end

function sim_fire()
 local li=flr(rnd(3))
 local po=rnd(1)<0.35 and 1 or 0
 demo_likes+=li demo_posts+=po roll()
 spawn(1,li) spawn(2,po)
 spawn(3,rnd(1)<0.12 and 1 or 0) spawn(4,rnd(1)<0.25 and 1 or 0)
end

function update_demo()
 local mx,my,mb=stat(32),stat(33),stat(34)&1
 local tap=mb==1 and demo_mb==0 and mx>=116 and mx<=127 and my>=1 and my<=12
 demo_mb=mb
 -- ❎ maps to x/v/m; route desktop keys by char so "m" cycles music, x/v quits.
 while stat(30) do
  local c=stat(31)
  if c=="m" then demo_track=demo_track%4+1 play_tune()
  elseif c=="x" or c=="v" then quit_demo() return end
 end
 if tap or (mobile() and btnp(5)) then quit_demo() return end
 demo_t+=1/30 df=(df+1)%2
 if demo_t>=cycle then demo_t-=cycle end
 update_birds()
 if time()-fire_t>1.5 then sim_fire() end
 if alt()>0.85 and rnd(1)<0.06 and #shoot<3 then
  add(shoot,{x=rnd(110),y=rnd(50),vx=2.5+rnd(2),vy=1+rnd(1.5)})
 end
 for s in all(shoot) do
  s.x+=s.vx s.y+=s.vy
  if s.x>134 or s.y>80 then del(shoot,s) end
 end
 for p in all(parts) do
  p.t+=1/30 p.y+=p.vy p.x+=sin(p.t*0.4)*0.5
  if p.kind==1 then
   if p.y>134 then del(parts,p) end
  elseif p.y<-6 then del(parts,p) end
 end
end

-- one continuous looped path: off-left -> rise to centre -> swell -> out left.
-- start (j=0) and end (j=1) coincide so the loop is seamless.
function bfly_pos()
 local bob=sin(time()*0.8)*3
 local a=alt()
 if demo_t<75 then        -- fly in from off-left, skim the valley, then rise
  return lerp(-20,64,eio(clmp(demo_t/24))),lerp(108,30,a)+bob,lerp(0.8,1,a)
 elseif demo_t<81 then    -- finale: swell at centre with a slow flap
  local u=(demo_t-75)/6
  return 64,lerp(30,56,eio(u)),lerp(1,5,eio(u))
 else                     -- fly out off-screen left (loop seam)
  local u=(demo_t-81)/6
  return lerp(64,-20,eio(u)),lerp(56,108,eio(u)),lerp(5,0.8,eio(u))
 end
end

function bfly_sx(spd)
 return bfly_seq[flr(time()*spd)%4+1]*8
end

function draw_bfly()
 local x,y,sc=bfly_pos()
 local w=16*sc
 local dx,dy=x-w/2,y-w/2
 bflysh(bfly_sx(demo_t>75 and 2.5 or 6),dx,dy,w)
end

-- procedural fire-spiral sun: rotating arm in fire colours + bright core
function fire_sun(cx,cy)
 for i=0,7 do  -- subtle flicker corona, close to the disc
  local a=i/8+time()*0.1
  local r=8+sin(time()*3+i)*1.5
  pset(cx+cos(a)*r,cy+sin(a)*r,9)
 end
 circfill(cx,cy,7,9)  -- orange rim
 circfill(cx,cy,5,10) -- yellow
 circfill(cx,cy,3,7)  -- bright core
end

gpat={0x0000,0xa0a0,0xa5a5,0xf5f5,0xffff}
-- vertical dithered gradient: colour b at the top, a at the bottom
function grad(y0,y1,a,b)
 local h=(y1-y0)/5
 for i=1,5 do
  fillp(gpat[i])
  rectfill(0,y0+(i-1)*h,127,y0+i*h,a+b*16)
 end
 fillp()
end

-- tall atmosphere gradient drawn full so upward pan reveals it continuously.
function draw_atmos()
 rectfill(0,0,127,150,0) -- deep space
 grad(150,212,1,0)       -- space -> night blue
 grad(212,274,13,1)      -- night -> dusk indigo
 grad(274,372,12,13)     -- dusk -> light-blue day
 grad(372,440,7,12)      -- day -> bright hazy horizon
end

function cloud(x,y)
 circfill(x,y,6,7) circfill(x+7,y+1,7,7)
 circfill(x+14,y,5,7) rectfill(x,y,x+14,y+5,7)
end

function draw_clouds()
 local s=demo_t*10
 cloud((s*0.6)%190-30,272)       -- drifts right
 cloud((-s*0.42+120)%190-30,300) -- drifts left
 cloud((s*0.3+50)%190-30,332)    -- drifts right (slow)
end

function draw_ground()
 local s=demo_t*14
 for x=0,127 do  -- per column, back-to-front: far hill, near hill+grass, stream
  rectfill(x,402+sin((x+s*0.3)/40)*7,x,440,3)
  rectfill(x,410+sin((x+s*0.7)/30)*8,x,440,11)
  local ry=424+sin((x+s)/46)*4
  rectfill(x,ry,x,ry+5,1)
  pset(x,ry,sin((x+s)/8)>0.55 and 12 or 1)
 end
 for i=0,11 do   -- foreground flowers
  pset((12+i*12-s)%150-8,434+sin(i)*3,8+i%2*6)
 end
end

function draw_night_sky()
 if alt()<0.3 then return end
 for st in all(stars) do
  if sin(time()*0.6+st.p)>-0.2 then
   pset(st.x,st.y,rnd(1)<0.3 and 6 or 7)
  end
 end
 local mx=18+max(0,demo_t-34)*0.4
 circfill(mx,24,8,7) circfill(mx+3,22,7,0)
 for s in all(shoot) do
  line(s.x,s.y,s.x-s.vx*3,s.y-s.vy*3,7)
  pset(s.x,s.y,10)
 end
end

-- credits during the night hold; show the running firehose totals
function draw_credits()
 local a=clmp((demo_t-54)/3)
 local y=lerp(132,52,eio(a))
 print_c("picosky",y,12)
 print_c("by vinnymac",y+9,7)
 print_c(fmtk(demo_lk,demo_likes).." likes  "..fmtk(demo_pk,demo_posts).." posts",y+22,12)
 print_c("live stats provided by",y+31,6)
 print_c("bluesky firehose",y+38,6)
 print_c("thanks to bluesky, zep,",y+50,6)
 print_c("and daniel linssen for m3x6",y+58,6)
end

function draw_hud()
 spr(10,4,3) spr(8,42,3)
 print(fmtk(demo_lk,demo_likes),13,4,7)
 print(fmtk(demo_pk,demo_posts),51,4,7)
 if time()-fire_t>1.5 then print("sim",102,4,9) end
end

-- round exit button + aligned esc label
function draw_exit()
 local cx,cy=122,6
 circfill(cx,cy,3,6) -- pearl button, half size
 line(cx-1,cy-1,cx+1,cy+1,5)
 line(cx-1,cy+1,cx+1,cy-1,5)
 print("esc",cx-18,cy-2,6)
end

function heart(x,y,c)
 circfill(x-1,y,1,c)
 circfill(x+1,y,1,c)
 line(x-2,y+1,x+2,y+1,c)
 line(x-1,y+2,x+1,y+2,c)
 pset(x,y+3,c)
end

function draw_parts()
 for p in all(parts) do
  if p.kind==1 then
   heart(p.x,p.y,p.c)
  elseif p.kind==4 then
   pset(p.x,p.y,p.c) pset(p.x,p.y-1,10)
  else
   circ(p.x,p.y,2,p.c) pset(p.x-1,p.y-1,7)
  end
 end
end

-- a small flock of tiny "v" birds: simplified boids (separate/cohere/align)
function init_birds()
 birds={}
 for _=1,6 do
  add(birds,{x=rnd(120),y=34+rnd(24),vx=0.3+rnd(0.3),vy=rnd(0.4)-0.2})
 end
end

function update_birds()
 if alt()>0.6 then return end
 for b in all(birds) do
  local cx,cy,vx,vy,n=0,0,0,0,0
  for o in all(birds) do
   local dx,dy=o.x-b.x,o.y-b.y
   local d=dx*dx+dy*dy
   if o~=b and d<400 then
    cx+=o.x cy+=o.y vx+=o.vx vy+=o.vy n+=1
    if d<144 then b.vx-=dx*0.025 b.vy-=dy*0.025 end
   end
  end
  if n>0 then
   b.vx+=(cx/n-b.x)*0.002+(vx/n-b.vx)*0.06
   b.vy+=(cy/n-b.y)*0.002+(vy/n-b.vy)*0.06
  end
  b.vx=mid(0.2,b.vx,1) b.vy=mid(-0.5,b.vy,0.5)
  b.x+=b.vx b.y+=b.vy
  b.y=mid(22,b.y,74)
  if b.x>134 then b.x=-6-rnd(16) b.y=34+rnd(24) end
 end
end

function draw_birds()
 if alt()>0.55 then return end
 for b in all(birds) do
  local w=sin(time()*4+b.x)>0 and 1 or 0
  line(b.x-2,b.y-w,b.x,b.y,5) line(b.x,b.y,b.x+2,b.y-w,5)
 end
end

-- screen palette darkening: lv 0=bright..6=black, smooth, no dither.
drk=split"0,0,1,1,2,1,5,6,2,4,9,3,13,1,2,5"  -- darken LUT, 1-based (drk[c+1] for colour c)
function setlight(lv)
 for c=0,15 do local d=c for _=1,lv do d=drk[d+1] end pal(c,d,1) end
end

-- byte->darkened-byte LUTs (one per level) in free RAM, for the per-pixel pass
function build_lut()
 for lv=0,6 do
  for b=0,255 do
   local lo,hi=b%16,b\16
   for _=1,lv do lo=drk[lo+1] hi=drk[hi+1] end
   poke(0x4300+lv*256+b,lo+hi*16)
  end
 end
end

-- sun light: scene drawn, then darken every pixel by a far from the sun, easing
-- to 0 at the centre (concentric rings). rows beyond the glow take a fast path.
function light_pass(sx,sy,a)
 local r=40 local rr=r*r local cb=sx\2
 for y=0,127 do
  local dy=y-sy local dy2=dy*dy local row=0x6000+y*64
  if dy2>=rr then
   local l=0x4300+a*256
   for ad=row,row+63 do poke(ad,peek(l+peek(ad))) end
  else
   local hw={[0]=0,[a+1]=64}
   for k=1,a do local q=(r*k/a)*(r*k/a)-dy2 hw[k]=q>0 and sqrt(q)\2 or 0 end
   for lv=0,a do
    local l=0x4300+lv*256 local i,o=hw[lv],hw[lv+1]
    for ad=row+mid(0,cb+i,63),row+mid(0,cb+o-1,63) do poke(ad,peek(l+peek(ad))) end
    for ad=row+mid(0,cb-o+1,63),row+mid(0,cb-max(i,1),63) do poke(ad,peek(l+peek(ad))) end
   end
  end
 end
end

-- loop-seam fade: to black over the last 3s, back from black over the first 3s
function seam()
 if demo_t>=cycle-3 then return flr((demo_t-cycle+3)/3*6+.5) end
 if demo_t<3 then return flr((1-demo_t/3)*6+.5) end
 return 0
end

-- dusk dimming: gradual, held through the day->night pan, released to 0 only
-- once the night sky is fully in view (gated on alt, so no bright-blue flash)
function amb()
 local t=demo_t
 if t<20 then return 0 end
 if t<28 then return flr((t-20)/8*2+.5) end
 if alt()<0.55 then return 2 end
 return flr(max(0,(0.66-alt())/0.11)*2+.5)
end

function draw_demo()
 local la,ls=amb(),seam()
 local suny=340-camtop()
 local glow=ls==0 and la>0 and suny<134
 if glow and df~=0 then return end  -- update the sun glow every other frame
 cls(0)
 camera(0,camtop())
 draw_atmos()
 draw_night_sky()
 fire_sun(96-demo_t*0.4,340)
 draw_clouds()
 draw_ground()
 camera()
 draw_birds()
 draw_parts()
 draw_bfly()
 if demo_t>54 and demo_t<75 then draw_credits() end
 if demo_t<53 then draw_hud() end
 if glow then
  setlight(0) light_pass(96-demo_t*0.4,suny,la)
 else
  setlight(max(la,ls))
 end
 if time()<track_lbl and seam()==0 then
  print_c(tunenames[demo_track],100,7)
  print_c(mobile() and "pause to change track" or "m: change music",108,6)
 end
 draw_exit()
end