From 3b57f9457a65f49007d9ced3a655d83fff1c1a91 Mon Sep 17 00:00:00 2001
From: Folkert Kevelam <contact@pyllr.nl>
Date: Mon, 18 Aug 2025 23:02:07 +0200
Subject: [PATCH] Initial commit

---
 lua/MarkdownPreviewer/app.lua      |  88 ++++++++++++++
 lua/MarkdownPreviewer/init.lua     |  70 +++++++++++
 lua/MarkdownPreviewer/msgpack.lua  | 183 +++++++++++++++++++++++++++++
 lua/MarkdownPreviewer/throttle.lua |  31 +++++
 4 files changed, 372 insertions(+)
 create mode 100644 lua/MarkdownPreviewer/app.lua
 create mode 100644 lua/MarkdownPreviewer/init.lua
 create mode 100644 lua/MarkdownPreviewer/msgpack.lua
 create mode 100644 lua/MarkdownPreviewer/throttle.lua

diff --git a/lua/MarkdownPreviewer/app.lua b/lua/MarkdownPreviewer/app.lua
new file mode 100644
index 0000000..1d2e6af
--- /dev/null
+++ b/lua/MarkdownPreviewer/app.lua
@@ -0,0 +1,88 @@
+local msgpack = require"MarkdownPreviewer.msgpack"
+chansend = vim.fn.chansend
+
+module = {}
+
+local function ToUint32(data)
+    local len = data
+    t = {}
+    for i=4,1,-1 do
+        t[i] = math.fmod(len, 256)
+        len = math.floor(len / 256)
+    end
+    return string.char(unpack(t))
+end
+
+local function Message(data)
+    local internal = msgpack.ToMsgPack(data)
+    return ToUint32(#internal) .. internal
+end
+
+app = {
+    cmd = nil,
+    channel = nil
+}
+
+function app:init(on_exit)
+    if self.channel then
+        return
+    end
+
+    local cwd = debug.getinfo(1, 'S').source:sub(2):match('(.*[/\\])')
+    self.channel = vim.fn.jobstart(self.cmd, {
+        cwd = cwd,
+        stderr_buffered = true,
+        on_exit = function()
+            vim.fn.chanclose(self.channel)
+            self.channel = nil
+            on_exit()
+        end,
+        on_stderr = function(channel, data, name)
+            print(vim.inspect(data))
+        end,
+        on_stdout = function(channel, data, name)
+            print(vim.inspect(data))
+        end
+    })
+end
+
+function app:show(content)
+    if self.channel == nil then
+        return
+    end
+
+    chansend(self.channel, Message({show = content}))
+end
+
+function app:scroll(content)
+    if self.channel == nil then
+        return
+    end
+
+    chansend(self.channel, Message({scroll = content}))
+end
+
+
+function app:stop()
+    if self.channel then
+        vim.fn.jobstop(self.channel)
+    end
+end
+
+function module.setup()
+    o = {}
+
+    setmetatable(o, app)
+    app.__index = app
+
+    o.cmd = {
+        "../../Server/run.sh",
+        "../../Server/venv",
+        'python3',
+        '../../Server/server.py'
+    }
+
+    return o
+end
+
+return module
diff --git a/lua/MarkdownPreviewer/init.lua b/lua/MarkdownPreviewer/init.lua
new file mode 100644
index 0000000..949f55c
--- /dev/null
+++ b/lua/MarkdownPreviewer/init.lua
@@ -0,0 +1,70 @@
+local client = require"MarkdownPreviewer.app"
+local throttle = require"MarkdownPreviewer.throttle"
+
+local nvim_buf_get_lines = vim.api.nvim_buf_get_lines
+local nvim_create_augroup = vim.api.nvim_create_augroup
+local nvim_create_autocmd = vim.api.nvim_create_autocmd
+local nvim_del_augroup_by_id = vim.api.nvim_del_augroup_by_id
+local concat = table.concat
+
+local function get_buf_content(bufnr)
+    local data = concat(nvim_buf_get_lines(bufnr, 0, -1, false), '\n'):gsub('%s*$', '')
+    return data
+end
+
+module = {}
+
+local server_connection
+
+function module.setup()
+    server_connection = client.setup()
+end
+
+function module.open()
+    augroup = nvim_create_augroup("MarkdownPreviewActiveAugroup", {clear = true})
+
+    server_connection:init(function()
+        augroup = nvim_del_augroup_by_id(augroup)
+    end)
+
+    local bufnr = vim.api.nvim_get_current_buf()
+    server_connection:show(get_buf_content(bufnr))
+    server_connection:scroll(vim.fn.line('.'))
+
+    nvim_create_autocmd("BufWritePost", {
+        group = augroup,
+        buffer = bufnr,
+        callback = function()
+            server_connection:show(get_buf_content(bufnr))
+        end,
+    })
+
+    nvim_create_autocmd({"CursorMoved", "CursorMovedI"}, {
+        group = augroup,
+        buffer = bufnr,
+        callback = function()
+            server_connection:scroll(vim.fn.line('.'))
+        end,
+    })
+
+    local function show()
+        server_connection:show(get_buf_content(bufnr))
+    end
+
+    nvim_create_autocmd({"TextChanged", "TextChangedI", "TextChangedP" }, {
+        group = augroup,
+        buffer = bufnr,
+        callback = function()
+            throttle.run_fn(show)
+        end,
+    })
+
+end
+
+function module.close()
+    if server_connection then
+        server_connection:stop()
+    end
+end
+
+return module
diff --git a/lua/MarkdownPreviewer/msgpack.lua b/lua/MarkdownPreviewer/msgpack.lua
new file mode 100644
index 0000000..1637307
--- /dev/null
+++ b/lua/MarkdownPreviewer/msgpack.lua
@@ -0,0 +1,183 @@
+module = {}
+
+local bit8 = 256
+local bit16 = 65535
+local bit32 = 4294967295
+local bit64 = 18446744070000001024
+
+local function ToUint16(length)
+    local len = length
+    t = {}
+    for i=2,1,-1 do
+        t[i] = math.fmod(len,256)
+        len = math.floor(len / 256)
+    end
+    return string.char(unpack(t))
+end
+
+local function ToUint32(length)
+    local len = length
+    t = {}
+    for i=4,1,-1 do
+        t[i] = math.fmod(len,256)
+        len = math.floor(len / 256)
+    end
+    return string.char(unpack(t))
+end
+
+local function ToUint64(length)
+    local len = length
+    t = {}
+    for i=8,1,-1 do
+        t[i] = math.fmod(len,256)
+        len = math.floor(len / 256)
+    end
+    return string.char(unpack(t))
+end
+
+local function is_array(t)
+    return type(t) == 'table' and (#t > 0 or next(t) == nil)
+end
+
+local function NilToMsgPack()
+    return string.char(0xc0)
+end
+
+local function StringToMsgPack(operand)
+    local str_len = #operand
+
+    if str_len <= 31 then
+        local header = string.char(0xa0 + str_len)
+        return header .. operand
+    elseif str_len <= bit8 - 1 then
+        local header = string.char(0xd9)
+        return header .. string.char(str_len) .. operand
+    elseif str_len <= bit16 - 1 then
+        local header = string.char(0xda)
+        return header .. ToUint16(str_len) .. operand
+    elseif str_len <= bit32 - 1 then
+        local header = string.char(0xdb)
+        return header .. ToUint32(str_len) .. operand
+    else
+        print("String too large")
+        return nil
+    end
+end
+
+local function NumberToMsgPack(operand)
+    if operand > 0 then
+        if operand <= 127 then
+            return string.char(operand)
+        elseif operand <= bit8 - 1 then
+            return string.char(0xcc) .. string.char(operand)
+        elseif operand <= bit16 - 1 then
+            return string.char(0xcd) .. ToUint16(operand)
+        elseif operand <= bit32 - 1 then
+            return string.char(0xce) .. ToUint32(operand)
+        elseif operand <= bit64 - 1 then
+            return string.char(0xcf) .. ToUint64(operand)
+        end
+    end
+
+    return nil
+end
+
+local function ArrayToMsgPack(operand)
+    local len = #operand
+
+    local data = ""
+
+    if len <= 15 then
+        data = data .. string.char(0x90 + len)
+    elseif len <= bit16 - 1 then
+        data = data .. string.char(0xdc) .. ToUint16(len)
+    elseif len <= bit32 - 1 then
+        data = data .. string.char(0xdd) .. ToUint32(len)
+    end
+
+    for i=1,len do
+        local element = operand[i]
+        if type(element) == 'nil' then
+            data = data .. NilToMsgPack()
+        elseif type(element) == 'number' then
+            data = data .. NumberToMsgPack(element)
+        elseif type(element) == 'string' then
+            data = data .. StringToMsgPack(element)
+        elseif type(element) == 'table' then
+            if is_array(element) then
+                data = data .. ArrayToMsgPack(element)
+            else
+                data = data .. TableToMsgPack(element)
+            end
+        end
+    end
+
+    return data
+end
+
+local function TableToMsgPack(operand)
+    local len = 0
+    for _,v in pairs(operand) do
+        len = len + 1
+    end
+
+    local data = ""
+
+    if len <= 15 then
+        data = data .. string.char(0x80 + len)
+    elseif len <= bit16 - 1 then
+        data = data .. string.char(0xde) .. ToUint16(len)
+    elseif len <= bit32 - 1 then
+        data = data .. string.char(0xdf) .. ToUint32(len)
+    end
+
+    for k,v in pairs(operand) do
+        if type(k) == 'nil' then
+            data = data .. NilToMsgPack()
+        elseif type(k) == 'number' then
+            data = data .. NumberToMsgPack(k)
+        elseif type(k) == 'string' then
+            data = data .. StringToMsgPack(k)
+        elseif type(k) == 'table' then
+            if is_array(k) then
+                data = data .. ArrayToMsgPack(k)
+            else
+                data = data .. TableToMsgPack(k)
+            end
+        end
+
+        if type(v) == 'nil' then
+            data = data .. NilToMsgPack()
+        elseif type(v) == 'number' then
+            data = data .. NumberToMsgPack(v)
+        elseif type(v) == 'string' then
+            data = data .. StringToMsgPack(v)
+        elseif type(v) == 'table' then
+            if is_array(v) then
+                data = data .. ArrayToMsgPack(v)
+            else
+                data = data .. TableToMsgPack(v)
+            end
+        end
+    end
+
+    return data
+end
+
+function module.ToMsgPack(operand)
+    if type(operand) == 'nil' then
+        return NilToMsgPack()
+    elseif type(operand) == 'number' then
+        return NumberToMsgPack()
+    elseif type(operand) == 'string' then
+        return StringToMsgPack()
+    elseif type(operand) == 'table' then
+        if is_array(operand) then
+            return ArrayToMsgPack(operand)
+        else
+            return TableToMsgPack(operand)
+        end
+    end
+end
+
+return module
diff --git a/lua/MarkdownPreviewer/throttle.lua b/lua/MarkdownPreviewer/throttle.lua
new file mode 100644
index 0000000..536f4bb
--- /dev/null
+++ b/lua/MarkdownPreviewer/throttle.lua
@@ -0,0 +1,31 @@
+local module = {}
+
+local defer = 1000
+local throttled = false
+local fn_to_run = nil
+
+local function throttle()
+    if fn_to_run then
+        fn_to_run()
+        fn_to_run = nil
+        vim.defer_fn(throttle, defer)
+    else
+        throttled = false
+    end
+end
+
+function module.run_fn(fn, args)
+    if throttled == true then
+        local function func()
+            fn(args)
+        end
+
+        fn_to_run = func
+    else
+        fn(args)
+        throttled = true
+        vim.defer_fn(throttle, defer)
+    end
+end
+
+return module