-- The functions and variables in this file are only for use in the mod itself.
-- Those that do real work should be local and wrapped in public functions
-- Minetest connector
local json = yl_cinema.dependencies.json
local F = minetest.formspec_escape
yl_cinema.watching = {}

local function warn(text)
    minetest.log("warning", "[yl_cinema] " .. text)
end

local function action(text)
    minetest.log("action", "[yl_cinema] " .. text)
end

-- JSON decoder
local function parse_json(json_str)
    return json.decode(json_str)
end

local function get_files_in_directory(folderpath)
    return minetest.get_dir_list(folderpath, true)
end

-- internal functions

local function format_table(t)
    -- Format of t must be {{row1,row2,row3, ...},{row1,row2,row3, ...},...}
    local blanks_between_rows = 3
    local max_row_length = {}
    for linenumber = 1, #t do
        for rownumber = 1, #t[linenumber] do
            local row_length = #tostring(t[linenumber][rownumber])
            if (max_row_length[rownumber] or 0) < row_length then
                max_row_length[rownumber] = row_length
            end
        end
    end

    local ret = {}

    for linenumber = 1, #t do
        local line_s = ""
        for rownumber = 1, #t[linenumber] do
            local text = t[linenumber][rownumber]
            local text_length = #tostring(text)
            local add_blanks = max_row_length[rownumber] - text_length
            local newtext = t[linenumber][rownumber]
            for add = 1, (add_blanks + blanks_between_rows) do
                newtext = newtext .. " "
            end
            line_s = line_s .. newtext
        end
        table.insert(ret,line_s)
    end
    return table.concat(ret, "\n")
end

local function remove_forbidden_characters(str)
    local pattern = "[^%w_]"
    return string.gsub(str, pattern, "_")
end

local function get_itemstring(movie_id)
    return yl_cinema.settings.movie_item_name .. "_" .. remove_forbidden_characters(movie_id)
end

local function remove_invisible_folders(folder_list)
    local filtered_list = {}
    for _, folder in ipairs(folder_list) do
        if not string.find(folder, "^%.") then
            table.insert(filtered_list, folder)
        end
    end
    return filtered_list or {}
end

local function watches(playername, movie_id)
    yl_cinema.watching[playername] = movie_id
end

local function watched_by(playername)
    return yl_cinema.watching[playername] or ""
end

local function stops_watching(player)
    local playername = player:get_player_name()
    yl_cinema.watching[playername] = nil
end

local function orderpages(a, b)
    return a.order < b.order
end

local function mediacallback(name)
    local target_name = name or ""
    action("mediacallback: File pushed to player " .. target_name)
end

local function string_to_recipe(s)
    local recipe = string.split(s, ",",true)
    if #recipe ~= 9 then
        return false
    end
    return {{recipe[1], recipe[2], recipe[3]}, {recipe[4], recipe[5], recipe[6]}, {recipe[7], recipe[8], recipe[9]}}
end

local function path_of_movie(movie_id)
    return yl_cinema.worldpath .. yl_cinema.settings.save_path .. DIR_DELIM .. movie_id .. DIR_DELIM .. movie_id ..
               ".json"
end

local function path_of_image(movie_id, name)
    return yl_cinema.worldpath .. yl_cinema.settings.save_path .. DIR_DELIM .. movie_id .. DIR_DELIM .. "textures" ..
               DIR_DELIM .. name
end

local function read_json_file(path)
    local file = io.open(path, "r")
    if not file then
        return false, "Error opening file: " .. path
    end

    local content = file:read("*all")
    file:close()

    if not content then
        return false, "Error reading file: " .. path
    end

    return true, parse_json(content)
end

local function get_movie(movie_id)
    return yl_cinema.movies[movie_id] or {}
end

local function load_image(path)
    local options = {
        filepath = path
    }
    return minetest.dynamic_add_media(options, mediacallback)
end

local function load_images_of_movie(movie_id)
    local movie = get_movie(movie_id)
    local loaded_count = 0
    for _, file in ipairs(movie.files) do
        local path = path_of_image(movie_id, file)
        local success = load_image(path)
        if success then
            loaded_count = loaded_count + 1
        end
    end

    return loaded_count, #movie.files
end

local function load_movie(movie_id)
    local file_path = path_of_movie(movie_id)
    local success, movie_data = read_json_file(file_path)
    local movie = "Error loading movie metadata from file " .. dump(file_path) .. ": " .. dump(movie_data)
    if success then
        movie = movie_data
    else
        warn(movie)
    end
    return success, movie
end

local function load_movies(movies_directory)
    local movies = {}
    local loaded_count = 0

    local folders = get_files_in_directory(movies_directory)
    local movie_files = remove_invisible_folders(folders)
    for _, movie_id in ipairs(movie_files) do
        local success, movie = load_movie(movie_id)
        if success then
            movies[movie_id] = movie
            loaded_count = loaded_count + 1
        end
    end

    return movies, loaded_count, #movie_files
end

function yl_cinema.load_movies()
    local movie_save_path = yl_cinema.worldpath .. yl_cinema.settings.save_path
    local movies, loaded_count, total_count = yl_cinema.load_movies(movie_save_path)
    if loaded_count ~= total_count then
        yl_cinema.warn(loaded_count .. "/" .. total_count .. " movies loaded.")
    else
        yl_cinema.action(loaded_count .. "/" .. total_count .. " movies loaded.")
    end
    return movies
end


local function search_movies(movies, search_term)
    local results = {}
    for movie_id, movie in pairs(movies) do
        if string.match(movie_id, search_term) or string.match(movie.name, search_term) or
            string.match(movie.description, search_term) then
                local item_string = ""
                if movie.item == true then
                    item_string = "yes"
                end
            table.insert(results, {movie_id, movie.name, item_string or ""})
        end
    end
    if #results > 0 then
        return true, results
    else
        return false, results
    end
end

local function get_movieformspec(movie_id, pagenum)

    local movie = yl_cinema.get_movie(movie_id)
    local screen_width = 12
    local screen_height = 6.75
    local screensize = screen_width .. "," .. 6.75

    local formspec = {}
    table.insert(formspec, "formspec_version[4]size[" .. screensize .. "]bgcolor[#000000]")

    if (not movie) or (not pagenum) then
        warn("Some error happened. movie=" .. dump(movie) .. ", page=" .. dump(pagenum))
        table.insert(formspec, "[0.5,0.5;Some Error happened.]")
        return table.concat(formspec, "")
    end

    if pagenum == 0 then
        table.insert(formspec, "background[0,0;" .. screensize .. ";" .. (F(movie.title_texture) or "") .. ";true]")
        table.insert(formspec, "label[0.5,0.5;" .. (F(movie.name) or "") .. "]")
        table.insert(formspec, "textarea[0.5,1.5;" .. screensize .. ";;" .. (F(movie.description) or "") .. ";]")
    else
        local page = movie.pages[pagenum]

        if not page then
            warn("Page empty = " .. dump(page))
            return ""
        end

        table.insert(formspec, "background[0,0;" .. screensize .. ";" .. (F(page.texture) or "") .. ";true]")
        table.insert(formspec, "label[" .. (F(page.captionposx) or 0) .. "," .. (F(page.captionposy) or 0) .. ";" ..
            (F(page.caption) or "") .. "]")

        if pagenum == #movie.pages then
            table.insert(formspec, "button[3," .. (F(screen_height) - 1) .. ";2,1;replay;Replay]")
            table.insert(formspec, "button_exit[6," .. (F(screen_height) - 1) .. ";2,1;exit;Exit]")
        end

    end

    return table.concat(formspec, "")
end

local function showpage(target_player_name, movie_id, pagenum)

    if not minetest.get_player_by_name(target_player_name) then
        return
    end
    if watched_by(target_player_name) == "" then
        return
    end

    local formspec = get_movieformspec(movie_id, pagenum)

    local movie = get_movie(movie_id)
    local pages = movie.pages

    if pagenum <= #pages then

        table.sort(pages, orderpages)

        local page = pages[pagenum] or {}

        local delay = page.duration or 3
        local nextpage = pagenum + 1
        minetest.after(delay, showpage, target_player_name, movie_id, nextpage)
        watches(target_player_name, movie_id)
        minetest.show_formspec(target_player_name, "yl_cinema:movie", formspec)
    end

end

--

minetest.register_on_player_receive_fields(function(player, formname, fields)
    if formname ~= "yl_cinema:movie" then
        return
    end

    local playername = player:get_player_name()

    if fields.exit or fields.quit then
        stops_watching(player)
    end

    if player and fields.replay then
        local movie_id = watched_by(playername)
        showpage(player:get_player_name(), movie_id, 0)
    end

    return true

end)

minetest.register_on_leaveplayer(stops_watching)
minetest.register_on_dieplayer(stops_watching)

-- Chatcommands

function yl_cinema.cmd_list_movies(name, param)

    local args = string.split(param, " ")

    if (#args > 1) then
        return false, "Usage: /listmovies [<searchstring>]"
    end

    local searchterm = args[1] or ""

    minetest.log("action", "[yl_cinema] Player " .. name .. " searches for movie " .. searchterm)

    local display_table = {{"movie_id","name","itemstring"}}

    local success, t = yl_cinema.listmovies(searchterm)

    for _,movies in ipairs(t) do
        table.insert(display_table, movies)
    end

    local nice_format = format_table(display_table)

    if success then
        return true, nice_format
    else
        return false, "No movies matching your criteria were found."
    end
end

function yl_cinema.cmd_show_movie(name, param)
    local args = string.split(param, " ")

    if (#args ~= 2) then
        return false, "Usage: /showmovie <playername> <movie>"
    end
    if not minetest.get_player_by_name(args[1]) then
        return false, "Player not online"
    end

    local target_player_name = args[1] or ""
    local movie_id = args[2] or ""

    minetest.log("action", "[yl_cinema] Player " .. name .. " shows movie " .. movie_id .. " to " .. target_player_name)

    local success, msg = yl_cinema.startmovie(movie_id, target_player_name)

    if success then
        return true, msg
    else
        return false, msg
    end
end

function yl_cinema.cmd_movie_reload(name, param)
    local args = string.split(param, " ")

    if (#args >= 2) then
        return false, "Usage: /movie_reload [<movie_id>]"
    end

    local movie_id = args[1] or ""

    action("[yl_cinema] Player " .. name .. " reloads movie " .. movie_id)




end


function yl_cinema.listmovies(searchterm)
    return search_movies(yl_cinema.movies, searchterm)
end

function yl_cinema.startmovie(movie_id, target_player_name)
    local pagenum = 0
    if not next(get_movie(movie_id)) then
        return false, "Movie " .. movie_id .. " not found."
    end
    watches(target_player_name, movie_id)
    -- Start to show a movie
    if minetest.get_player_by_name(target_player_name) then
        showpage(target_player_name, movie_id, pagenum)
        return true, "Movie " .. movie_id .. " started for " .. target_player_name
    else
        return false, "Player " .. target_player_name .. " not found."
    end
end

function yl_cinema.load(filename, ...)
    return read_json_file(filename, ...)
end

function yl_cinema.load_movies(movies_directory, ...)
    return load_movies(movies_directory, ...)
end

function yl_cinema.search_movies(movies, search_term, ...)
    return search_movies(movies, search_term, ...)
end

function yl_cinema.path_of_movie(movie_id, ...)
    return path_of_movie(movie_id, ...)
end

function yl_cinema.load_images_of_movie(movie_id, ...)
    return load_images_of_movie(movie_id, ...)
end

function yl_cinema.get_movie(movie_id, ...)
    return get_movie(movie_id, ...)
end

function yl_cinema.string_to_recipe(recipestring, ...)
    return string_to_recipe(recipestring, ...)
end

function yl_cinema.orderpages(a, b, ...)
    return orderpages(a, b, ...)
end

function yl_cinema.get_itemstring(movie_id, ...)
    return get_itemstring(movie_id, ...)
end

yl_cinema.action = action
yl_cinema.warn = warn