local immutable = require"immutable"

local bright = string.char(27).."[1m"
local blue = string.char(27).."[34m"
local reset = string.char(27).."[0m"
local function say(...) io.write(bright..blue); print(...); io.write(reset); end
local function repr(t)
    local tmp = {}
    for k,v in pairs(t) do tmp[#tmp+1] = ("%s=%s"):format(k,v) end
    return "{"..table.concat(tmp, ", ").."}"
end

local Vec = immutable({"x","y"}, {
    len2=function(self)
        return self.x*self.x + self.y*self.y
    end,
}, {
    __add=function(self, other)
        local cls = getmetatable(self)
        return cls(self.x+other.x, self.y+other.y)
    end,
    __tostring=function(self)
        return "Vec("..tostring(self.x)..", "..tostring(self.y)..")"
    end,
})

local v = Vec(1,3)
say(v)
local also_v = Vec(1,3)
say(also_v)
-- Hash collision right now
local not_v = Vec(true,3)
say(not_v)
local also_not_v = Vec(true,3)
say(also_not_v)

say(v == also_v)
say(v + Vec(5,6))
collectgarbage()
say(Vec("hello", "world"))
say(Vec("hello", "world"))
collectgarbage()
collectgarbage()

say("Let's look at the instances")
for h,b in pairs(Vec.__instances) do
    say(("Hash bucket: 0x%x"):format(h))
    for k,v in pairs(b) do
        local tmp = {}
        for kk,vv in pairs(v) do tmp[#tmp+1] = tostring(vv) end
        say('    <'..table.concat(tmp, ", ")..'>')
    end
end

local FooVec = immutable({"x","y"}, {
    len2=function(self)
        return self.x*self.x + self.y*self.y
    end,
}, {
    __add=function(self, other)
        local cls = getmetatable(self)
        return cls(self.x+other.x, self.y+other.y)
    end,
    __tostring=function(self)
        return "Vec("..tostring(self.x)..", "..tostring(self.y)..")"
    end,
})

say("FooVec: "..tostring(FooVec(1,3)))
say("FooVec == Vec: "..tostring(FooVec(1,3) == Vec(1,3)))
say("FooVec:len2() = "..tostring(FooVec(1,3):len2()))