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('.'), 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