obs           = obslua
my_settings   = nil

Input_Table   = {}
Output_String = ""
max_fields    = 100  -- Safety catch. Input loop will stop after attempting to read this many lines. If more text objects are used, increase only as necessary.

activeId      = 0
activated     = false
oops_count    = 0
stop_me       = false


-- Causes text to be updated during OBS startup.
function source_activated(cd)
    obs.remove_current_callback()

    if Update_Table() then Update_Text() end

    obs.script_log(obs.LOG_INFO, string.format("Initialization completed (1)"))
    obs.timer_add(startup_safety_callback, 250)
end
-- Occassionally, problems occur during startup routine. The following forces a second attempt to load and set data.
function startup_safety_callback()
    obs.timer_remove(startup_safety_callback)

    Input_Table = {}
    if Update_Table() then Update_Text() end
    obs.script_log(obs.LOG_INFO, string.format("Initialization completed (2)"))
end

local function checkFile(id)
	-- if the script has reloaded then stop any old timers
	if id < activeId then
		obs.remove_current_callback()
		return
	end

	if obs.obs_data_get_bool(my_settings, "debug") then
        obs.script_log(obs.LOG_INFO,
                       string.format("(%d) Checking text file...(%d)",
                                     id,
                                     obs.obs_data_get_int(my_settings, "interval")))
    end

    if Update_Table() then Update_Text() end
end

-- Loads file into a data table. Returns true if any updated (or new) values have been added to the text file.
function Update_Table()
    local changed = false

    -- Check for and open existing file.
    local filename = obs.obs_data_get_string(my_settings, "load_Filename")
    local f = io.open(filename, "r")
    if f == nil then
        print("Error: File does not exist or could not open file for reading.")
        return false
    end

    -- Convert file contents to paired list
    local content = f:read("*a")
    io.close(f)

    local name, value
    local count = 0

    while string.len(content) > 0 do
        count = count + 1
        name = ""
        value = ""

        local findTB = string.find(content, "\t")
        local findNL = string.find(content, "\n")
        if not findNL then findNL = string.len(content) end

        -- If no tab character on line, skip the line
        if not findTB or findTB > findNL then
            content = string.sub(content,findNL+1)

        -- Found a tab, get the value
        else
            name = string.sub(content,0,findTB-1)
            value = string.sub(content,findTB+1,findNL-1)
            content = string.sub(content,findNL+1)

            if string.len(name) > 0 then
                -- Data doesn't exist yet
                if not Input_Table[name] then
                    Input_Table[name] = value
                    changed = true
                -- Data changed
                elseif Input_Table[name] ~= value then
                    Input_Table[name] = value
                    changed = true
                end
            end
        end

        -- Warning: Script does not check for data fields REMOVED from the text file while running.
        -- If data is removed, the field will continue to be set back to the original value if changed.

        -- Error Catch: If file read goes haywire, stop at N-th loop.
        if count > max_fields then content = "" end
    end

    count = 0
    return changed
end

-- Inserts the values loaded from the text file into OBS text fields.
function Update_Text()
    for name, value in pairs(Input_Table) do
        local source = obs.obs_get_source_by_name(name)
        if not source then
            -- Catch event where no OBS field has the specified name
            print("Error: Could not find source: " .. name)
        else
            -- Update the text value of the OBS field matching the specified name.
            -- Warning: This could go wrong if the name matches up with something that does not have a text value.
            local settings = obs.obs_data_create()
            obs.obs_data_set_string(settings, "text", value)
            obs.obs_source_update(source, settings)
            obs.obs_data_release(settings)
            obs.obs_source_release(source)
        end
    end
end

-- Creates an input file based on the current OBS text fields. If file already exists, nothing is saved.
function Generate_File()
    -- Generate output string
    Output_String = ""
    local sources = obs.obs_enum_sources()
    if sources ~= nil then
        for _, source in ipairs(sources) do
            source_id = obs.obs_source_get_unversioned_id(source)
            if source_id == "text_gdiplus" or source_id == "text_ft2_source" then
                local name = obs.obs_source_get_name(source)

                local settings = obs.obs_source_get_settings(source)
                local text = obs.obs_data_get_string(settings, "text")
                obs.obs_data_release(settings)

                Output_String = Output_String .. name .. "\t" .. text .. "\n"
            end
        end
    end
    obs.source_list_release(sources)
    
    -- Check for existing file before overwriting.
    local filename = obs.obs_data_get_string(my_settings, "load_Filename")
    local f = io.open(filename, "r")
    if f ~= nil then
        io.close(f)
        print("Error: File already exists! Overwriting is not supported.")
        return
    end
        
    -- Open and output to a new file
    f = assert(io.open(filename, "w"))
    f:write(Output_String)
    f:close()
end

-- Force the file to reload and update immediately. Table previously loaded is dumped, and table is completely reloaded.
function update_button_clicked(props, p)
    -- force reload of entire table. only applies with manual update button.
    Input_Table = {}

    if Update_Table() then Update_Text() end

	return false
end

function generate_button_clicked(props, p)
    Generate_File()
    return false
end 

-------------------------------------------------------------------------------------------------

function script_properties()
    local props = obs.obs_properties_create()

    -- Data Filename
    obs.obs_properties_add_text(props, "load_Filename", "Data Filename", obs.OBS_TEXT_DEFAULT)

    -- File Monitor
    local m = obs.obs_properties_add_bool(props, "file_monitor", "Monitor File for Changes")
	obs.obs_property_set_modified_callback(m, trigger_mode_changed)
    obs.obs_properties_add_int(props, "interval", "Interval (ms)", 1000, 30000, 500)

    -- Update Now Button
    obs.obs_properties_add_button(props, "update_button", "Update Now", update_button_clicked)

    -- Generate File Button
    obs.obs_properties_add_button(props, "generate_button", "Generate File", generate_button_clicked)

    -- Debug
    obs.obs_properties_add_bool(props, "debug", "Debug")

    obslua.obs_properties_apply_settings(props, my_settings)
    return props
end
function trigger_mode_changed(props, property, settings)
    local monitor = obs.obs_data_get_bool(settings, "file_monitor")

    -- Set visibility for interval property
    obs.obs_property_set_visible(obslua.obs_properties_get(props, "interval"), monitor)

    -- Stop file monitor timer
    if not monitor then
        activeId = activeId + 1
    end

    return true
end

function script_description()
    return
    [[
        <center><h2>Text Loader</h2></center>
        <p>Information will be loaded from a text file and placed into OBS text objects matching names found
        in the file.</p>
        <p>Updates will be applied as follows:</p>
        <ul>
          <li>The file will automatically load at OBS startup.</li>
          <li>If the checkbox option is selected the script will monitor for changes in the text box and
              update text items as appropriate.</li>
          <li>A manual update may also be triggered by pressing the 'Update Now' button below.</li>
        </ul>
        <p>Information is stored in a tab-delimited file. The text <em>before</em> the first tab should match
        a text object name in OBS. Text <em>after</em> the tab and <em>up to the end of that line</em>, will
        be placed into the text object. For a sample file format, choose a filename for a <b>new</b> file and
        click the 'Generate File' button.</p>
        <hr/>
    ]]
end

function script_update(settings)
    my_settings = settings

    if not obs.obs_data_get_string(settings, "load_Filename") then
        obs.script_log(obs.LOG_INFO, string.format("Text monitor stopped"))
        return nil
    end
    if not obs.obs_data_get_bool(settings, "file_monitor") then
        obs.script_log(obs.LOG_INFO, string.format("Text monitor stopped"))
        return nil
    end

    activeId = activeId + 1
	local id = activeId
	obs.timer_add(function() checkFile(id) end,
                  obs.obs_data_get_int(settings, "interval"))
	obs.script_log(obs.LOG_INFO, string.format("Text monitor started"))
end

function script_defaults(settings)
    obs.obs_data_set_default_string(settings, "load_Filename", "")
    obs.obs_data_set_default_bool(settings, "file_monitor", false)
    obs.obs_data_set_default_int(settings, "interval", 10000)
	obs.obs_data_set_default_bool(settings, "debug", false)
end

function script_load(settings)
	local sh = obs.obs_get_signal_handler()
	obs.signal_handler_connect(sh, "source_activate", source_activated)
end