local mp = require 'mp'

-- path to csv file
local csv_filename = 'sheet.csv'
local csv_entry_separator = '\n' -- change it to ',' if you want all the entries in a single line
local allow_repeats = true

-- this function returns csv entry that will be written to file
-- edit this function to your liking
--
-- i wrapped it in a function, so that any additional logic will not fuck up anything else
--
-- reference:
-- https://mpv.io/manual/master/#command-interface-filename
-- https://mpv.io/manual/master/#command-interface-path
function get_csv_entry()
    -- reference: https://mpv.io/manual/master/#properties
    local filename = mp.get_property('filename')
    local filesize = mp.get_property('file-size')

    filename = filename:gsub('%,', '.') -- replace all ',' with '.' in filename to avoid csv conflicts

    csv_entry = filename .. ',' .. filesize

    -- could be useful for debugging
    -- mp.osd_message('csv_entry: ' .. tostring(csv_entry))
    return csv_entry
end

-- this function determines if the entry should be written to the csv file
-- it takes get_csv_entry result as an argument, feel free to use (or completely ignore) it
--
-- >if it meets certain parameters? like, reaching 80% of the lenght or something like that
-- i have no bloody idea what's that supposed to mean
function check_file(csv_entry)
    -- example logic - only mp4 files will be written to csv
    local filename = mp.get_property('filename')
    if csv_entry ~= '' and filename:find('mp4') then
        return true
    end

    return false
end

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

function on_file_loaded()
    local csv_entry = get_csv_entry()
    if not csv_entry or not check_file(csv_entry) then
        -- could be useful for debugging
        -- mp.osd_message('File didn\'t pass verification')
        return -- do nothing if the file verification didn't pass
    end

    -- uncomment for debugging
    -- mp.osd_message('File verification passed')

    local file_contents = {}
    local is_repeat = false

    -- read current file contents if file exists
    local csv_file = io.open(csv_filename, 'r')
    if csv_file then
        for line in csv_file:lines() do
            if not is_repeat and line == csv_entry then
                is_repeat = true
            end

            table.insert(file_contents, line)
        end

        csv_file:close()
    end

    -- append new entry at the end of the file (unless it's a repeat and repeats are disallowed)
    if allow_repeats or not is_repeat then
        file_contents[#file_contents + 1] = csv_entry
    end

    -- sort file contents; you can pass your own comparator if you want to
    -- reference: http://lua-users.org/wiki/TableLibraryTutorial
    table.sort(file_contents)

    -- open file for writing
    csv_file = io.open(csv_filename, 'w')
    if not csv_file then
        mp.osd_message('Could not open ' .. tostring(csv_filename) .. ' file for writing')
        return
    end

    -- write file entry by entry
    for index, line in pairs(file_contents) do
        if csv_entry_separator == '\n' then
            csv_file:write(line,  csv_entry_separator)
        elseif index > 1 then
            csv_file:write(csv_entry_separator, line)
        else
            csv_file:write(line)
        end
    end

    csv_file:close()
end

mp.register_event('file-loaded', on_file_loaded)