local Y=require("yaru.core")
local gfx=require("yaru.gfx")
local ui=require("yaru.ui")
local fs=require("filesystem")
local unicode=require("unicode")
local usub,ulen=unicode.sub,unicode.len

local M={}

local KW={}
for w in("and break do else elseif end false for function goto if in local nil not or repeat return then true until while"):gmatch("%S+")do KW[w]=true end


local function lexLua(line,inComment)
local out,i,n={},1,#line
local function push(a,b,k)out[#out+1]={a,line:sub(a,b),k}end
if inComment then
local e=line:find("]]",1,true)
if not e then push(1,n,"com")return out,true end
push(1,e+1,"com");i=e+2
end
while i<=n do
local c=line:sub(i,i)
if line:sub(i,i+3)=="--[["then
local e=line:find("]]",i+4,true)
if not e then push(i,n,"com")return out,true end
push(i,e+1,"com");i=e+2
elseif line:sub(i,i+1)=="--"then push(i,n,"com")break
elseif c=='"'or c=="'"then
local j=i+1
while j<=n do
local d=line:sub(j,j)
if d=="\\"then j=j+1 elseif d==c then break end
j=j+1
end
push(i,math.min(j,n),"str");i=j+1
elseif line:sub(i,i+1)=="[["then
local e=line:find("]]",i+2,true)or n-1
push(i,e+1,"str");i=e+2
elseif c:match("%d")then
local e=select(2,line:find("^[%w%.]*",i))
push(i,e,"num");i=e+1
elseif c:match("[%a_]")then
local e=select(2,line:find("^[%w_]*",i))
local word=line:sub(i,e)
push(i,e,KW[word]and"kw"or"txt");i=e+1
else
local e=select(2,line:find("^[^%w_\"'%-%[]*",i))
if e<i then e=i end
push(i,e,"txt");i=e+1
end
end
return out,false
end

function M.open(path)
local ed={lines={""},cx=1,cy=1,top=1,left=0,path=path,dirty=false,lua=false,find=nil}
local win

local function setTitle()
local name=ed.path and fs.name(ed.path)or"Untitled Document"
win.title=(ed.dirty and"• "or"")..name
end

local function loadFile(p)
ed.lines={}
local f=io.open(p,"r")
if f then
local data=f:read("*a")or""
f:close()
data=data:gsub("\r\n","\n"):gsub("\t","  ")
for l in(data.."\n"):gmatch("(.-)\n")do ed.lines[#ed.lines+1]=l end
if#ed.lines>1 and ed.lines[#ed.lines]==""and data:sub(-1)=="\n"then ed.lines[#ed.lines]=nil end
end
if#ed.lines==0 then ed.lines[1]=""end
ed.path,ed.dirty,ed.cx,ed.cy,ed.top,ed.left=p,false,1,1,1,0
ed.lua=p:match("%.lua$")~=nil
ed.ro=fs.get(p)and fs.get(p).isReadOnly()
setTitle()
end

local function save(p,after)
p=p or ed.path
if not p then
Y.dialog{title="Save As",text="File name (full path)",entry="/home/untitled.txt",buttons={{"Cancel"},
{"Save",function(txt)if txt and txt~=""then save(txt,after)end end,"suggested"}}}
return
end
local f,err=io.open(p,"w")
if not f then return Y.notify("Could not save",tostring(err))end
f:write(table.concat(ed.lines,"\n"),"\n")
f:close()
ed.path,ed.dirty=p,false
ed.lua=p:match("%.lua$")~=nil
setTitle()
for _,w in ipairs(Y.windowsOf("files"))do if w.reload then w.reload()end end
if after then after()end
end

win=Y.newWindow{app="editor",title="Text Editor",w=84,h=28,minW=40,minH=8,showTitle=true}
if path then
if fs.exists(path)then loadFile(path)else ed.path=path;ed.lua=path:match("%.lua$")~=nil;setTitle()end
else setTitle()end

local function line()return ed.lines[ed.cy]end
local function clampX()ed.cx=math.max(1,math.min(ed.cx,ulen(line())+1))end
local function modified()if not ed.dirty then ed.dirty=true;setTitle()end end

local function insert(s)
local l=line()
local parts={}
for p in(s.."\n"):gmatch("(.-)\n")do parts[#parts+1]=p end
local before,after=usub(l,1,ed.cx-1),usub(l,ed.cx)
if#parts==1 then
ed.lines[ed.cy]=before..parts[1]..after
ed.cx=ed.cx+ulen(parts[1])
else
ed.lines[ed.cy]=before..parts[1]
for i=2,#parts do table.insert(ed.lines,ed.cy+i-1,parts[i])end
ed.cy=ed.cy+#parts-1
ed.cx=ulen(parts[#parts])+1
ed.lines[ed.cy]=ed.lines[ed.cy]..after
end
modified()
end

local function findNext(q,from)
if not q or q==""then return end
local n=#ed.lines
for k=0,n do
local y=(ed.cy-1+k)%n+1
local start=(k==0)and(from or ed.cx)or 1
local l=ed.lines[y]
local bytePos=utf8.offset(l,start)or#l+1
local p=unicode.lower(l):find(unicode.lower(q),bytePos,true)
if p then
ed.cy=y
ed.cx=ulen(l:sub(1,p-1))+1
return true
end
end
Y.notify("Text Editor","“"..q.."” not found")
end

local GUT=5
local colors
local function openDialog()
Y.dialog{title="Open File",text="Full path",entry=ed.path and fs.path(ed.path)or"/home/",buttons={{"Cancel"},
{"Open",function(p)if p and p~=""then
if not ed.dirty and#ed.lines==1 and ed.lines[1]==""then loadFile(p)else M.open(p)end
end end,"suggested"}}}
end
function win.header(w,hw)
ui.button(w,2,1,"Open ▾",openDialog,nil,8)
ui.button(w,11,1,"+",function()M.open()end,"flat",3)
ui.button(w,hw-7,1,"Save",function()save()end,nil,6)
end

function win.draw(w,cw,ch)
local t=Y.theme
colors=colors or{}
local dark=t.dark
local C={kw=dark and 0xF66151 or 0xA51D2D,str=dark and 0xE9AD0C or 0x986A44,com=dark and 0x77767B or 0x9A9996,
num=dark and 0xC061CB or 0x813D9C,txt=t.fg}
local rows=ch-1-(ed.find and 1 or 0)
local tw=cw-GUT
if ed.cy<ed.top then ed.top=ed.cy end
if ed.cy>=ed.top+rows then ed.top=ed.cy-rows+1 end
if ed.cx-1<ed.left then ed.left=ed.cx-1 end
if ed.cx-1>=ed.left+tw-1 then ed.left=ed.cx-tw+1 end
gfx.fill(1,1,GUT,rows,t.sidebar)
gfx.fill(GUT+1,1,tw,rows,t.view)

local inCom=false
if ed.lua then
for y=1,ed.top-1 do
local l=ed.lines[y]
if l:find("--[[",1,true)or inCom then
local _,c=lexLua(l,inCom);inCom=c
end
end
end
for r=1,rows do
local y=ed.top+r-1
local l=ed.lines[y]
if not l then break end
local cur=y==ed.cy
gfx.text(1,r,string.format("%4d",y),cur and t.fg or t.dim,cur and(dark and 0x383838 or 0xDEDDDA)or t.sidebar)
if cur then gfx.fill(GUT+1,r,tw,1,dark and 0x2A2A2A or 0xF6F5F4)end
local bg=cur and(dark and 0x2A2A2A or 0xF6F5F4)or t.view
if ed.lua then
local toks
toks,inCom=lexLua(l,inCom)
for _,tk in ipairs(toks)do
local col=ulen(l:sub(1,tk[1]-1))-ed.left
local s=tk[2]
local sl=ulen(s)
if col+sl>0 and col<tw then
if col<0 then s=usub(s,1-col);col=0 end
if col+ulen(s)>tw then s=usub(s,1,tw-col)end
gfx.text(GUT+1+col,r,s,C[tk[3]],bg)
end
end
else
gfx.text(GUT+1,r,usub(l,ed.left+1,ed.left+tw),t.fg,bg)
end
if Y.focus==w and cur then
local cc=usub(l,ed.cx,ed.cx)
gfx.cell(GUT+ed.cx-ed.left,r,cc~=""and cc or" ",t.view,t.accent)
end
local ln=y
ui.hit(w,GUT+1,r,tw,1,function(_,px)ed.cy=ln;ed.cx=px-GUT+ed.left;clampX()end)
end
ui.scrollbar(cw,1,rows,ed.top-1,rows,#ed.lines)

if ed.find then
local fy=ch-1
gfx.fill(1,fy,cw,1,t.sidebar)
gfx.text(2,fy,"Find:",t.dim,t.sidebar)
ui.entry(w,ed.find,8,fy,math.min(40,cw-20),true)
ui.button(w,math.min(48,cw-11),fy,"Next",function()findNext(ed.find.text,ed.cx+1)end,nil,6)
ui.button(w,cw-3,fy,"×",function()ed.find=nil end,"flat",3)
end

gfx.fill(1,ch,cw,1,t.sidebar)
local st=string.format("Ln %d, Col %d",ed.cy,ed.cx)
local mode=(ed.lua and"Lua"or"Plain Text")..(ed.ro and"  (read-only)"or"")
gfx.text(2,ch,ui.trunc(ed.path or"Untitled",cw-30),t.dim,t.sidebar)
gfx.text(cw-unicode.len(st)-unicode.len(mode)-5,ch,mode.."   "..st,t.dim,t.sidebar)
end

function win.scroll(w,x,y,dir)
ed.top=math.max(1,math.min(#ed.lines,ed.top-dir*3))
ed.cy=math.max(ed.top,math.min(ed.cy,ed.top+w.h-4))
clampX()
end

function win.paste(w,s)
if ed.find then ui.entryPaste(ed.find,s)return end
insert((s:gsub("\r\n","\n"):gsub("\t","  ")))
end

function win.key(w,char,code)
local K=Y.K
local c,sh=Y.mods.ctrl(),Y.mods.shift()
if ed.find and not c then
local r=ui.entryKey(ed.find,char,code)
if r=="enter"then findNext(ed.find.text,ed.cx+1)
elseif r=="esc"then ed.find=nil end
if r then return end
end
if c then
if code==K.s then if sh then local p=ed.path;ed.path=nil;save(nil);if not ed.path then ed.path=p end else save()end
elseif code==0x18 then
openDialog()
elseif code==0x31 then M.open()
elseif code==0x21 then ed.find=ed.find or{text="",cur=0};ed.find.cur=ulen(ed.find.text)
elseif code==0x22 then if ed.find then findNext(ed.find.text,ed.cx+1)end
elseif code==K.c then Y.clipboard=line().."\n"
elseif code==0x2D or code==0x25 then
Y.clipboard=line().."\n"
if#ed.lines>1 then table.remove(ed.lines,ed.cy)else ed.lines[1]=""end
ed.cy=math.min(ed.cy,#ed.lines);clampX();modified()
elseif code==K.v or code==0x16 then
local s=Y.clipboard or""
if s:sub(-1)=="\n"then
ed.cx=1;insert(s);ed.cx=1
else insert(s)end
elseif code==K.home then ed.cy,ed.cx=1,1
elseif code==K["end"]then ed.cy=#ed.lines;ed.cx=ulen(line())+1
elseif code==K.d then
table.insert(ed.lines,ed.cy+1,line());ed.cy=ed.cy+1;modified()
end
return
end
local l=line()
if code==K.left then
if ed.cx>1 then ed.cx=ed.cx-1 elseif ed.cy>1 then ed.cy=ed.cy-1;ed.cx=ulen(line())+1 end
elseif code==K.right then
if ed.cx<=ulen(l)then ed.cx=ed.cx+1 elseif ed.cy<#ed.lines then ed.cy=ed.cy+1;ed.cx=1 end
elseif code==K.up then ed.cy=math.max(1,ed.cy-1);clampX()
elseif code==K.down then ed.cy=math.min(#ed.lines,ed.cy+1);clampX()
elseif code==K.pgup then ed.cy=math.max(1,ed.cy-(w.h-3));clampX()
elseif code==K.pgdn then ed.cy=math.min(#ed.lines,ed.cy+(w.h-3));clampX()
elseif code==K.home then
local ind=ulen(l:match("^%s*"))
ed.cx=(ed.cx==ind+1)and 1 or ind+1
elseif code==K["end"]then ed.cx=ulen(l)+1
elseif code==K.enter or code==0x9C then
local ind=l:match("^%s*")
if ed.lua and usub(l,1,ed.cx-1):match("[%(%{]%s*$")or usub(l,1,ed.cx-1):match("%f[%w]then%s*$")or usub(l,1,ed.cx-1):match("%f[%w]do%s*$")
or usub(l,1,ed.cx-1):match("function[^%)]*%)%s*$")then ind=ind.."  "end
insert("\n"..ind)
elseif code==K.back then
if ed.cx>1 then
local before=usub(l,1,ed.cx-1)
local n=(before:match("^%s+$")and#before%2==0 and#before>=2)and 2 or 1
ed.lines[ed.cy]=usub(l,1,ed.cx-1-n)..usub(l,ed.cx)
ed.cx=ed.cx-n
modified()
elseif ed.cy>1 then
local prev=ed.lines[ed.cy-1]
ed.cx=ulen(prev)+1
ed.lines[ed.cy-1]=prev..l
table.remove(ed.lines,ed.cy)
ed.cy=ed.cy-1
modified()
end
elseif code==K.del then
if ed.cx<=ulen(l)then ed.lines[ed.cy]=usub(l,1,ed.cx-1)..usub(l,ed.cx+1);modified()
elseif ed.cy<#ed.lines then ed.lines[ed.cy]=l..table.remove(ed.lines,ed.cy+1);modified()end
elseif code==K.tab then insert("  ")
elseif char and char>=32 and char~=127 then
insert(unicode.char(char))

if ed.lua then
local cl=line()
local ind,word=cl:match("^(%s+)(%S+)$")
if ind and#ind>=2 and ed.cx==ulen(cl)+1 and(word=="end"or word=="else"or word=="until"or word=="}")then
local prev=ed.lines[ed.cy-1]
local pind=prev and#prev:match("^%s*")or 0
if#ind>pind-2 then ed.lines[ed.cy]=cl:sub(3);ed.cx=ed.cx-2 end
end
end
end
end

function win.onclose(w)
if not ed.dirty then return true end
Y.dialog{title="Save changes to “"..(ed.path and fs.name(ed.path)or"Untitled Document").."” before closing?",
text="If you don't save, changes will be permanently lost.",
buttons={{"Cancel"},{"Close without Saving",function()Y.closeWin(w,true)end,"destructive"},
{"Save",function()save(nil,function()Y.closeWin(w,true)end)end,"suggested"}}}
return false
end
return win
end

return M