local fzf = require("fzf-lua")
local fn = vim.fn
local uv = vim.loop
local current_season = "S3"

-- Function to scan for .unicourse files and get their course directories
function get_course_directories()
    local dirs = {}
    local function scan_dir(dir)
        for _, entry in ipairs(fn.glob(dir .. "/*", true, true)) do
            if fn.isdirectory(entry) == 1 then
                local unicourse_file = entry .. "/.unicourse"
                if fn.filereadable(unicourse_file) == 1 then
                    local course_info = {}
                    for line in io.lines(unicourse_file) do
                        if line:match("^name: ") then
                            course_info.name = line:sub(7)
                        elseif line:match("^short: ") then
                            course_info.short = line:sub(8)
                        end
                    end
                    if course_info.name and course_info.short then
                        table.insert(dirs, { name = course_info.name, short = course_info.short, path = entry })
                    end
                end
            end
        end
    end

    scan_dir("/home/jonas/projects/university/" .. current_season)  -- Assuming all your courses are under the S2 folder
    return dirs
end

-- Function to show the fzf menu for selecting a course directory
function select_course_directory()
    local courses = get_course_directories()
    local course_names = {}

    for _, course in ipairs(courses) do
        table.insert(course_names, course.name .. " (" .. course.short .. ")")
    end

    fzf.fzf_exec(course_names, {
        prompt = "Select a course > ",
        actions = {
            ["default"] = function(selected)
                for _, course in ipairs(courses) do
                    if selected[1] == (course.name .. " (" .. course.short .. ")") then
                        show_course_menu(course)
                        break
                    end
                end
            end,
        },
    })
end

-- Function to show the fzf menu for actions on a selected course folder
function show_course_menu(course)
    local files = {}
    -- Collect all VL files in the Vorlesungen directory
    for _, file in ipairs(fn.glob(course.path .. "/VL/*", true, true)) do
        if file:match("%.typ$") then
            table.insert(files, file)
        end
    end

    -- Collect options
	-- TODO: implement zettel (Hausaufgaben) management
	-- For example creation of new ones and quick opening of the pdfs
    local options = {
        "Open the newest VL file",
        "Create a new VL",
        "Open the course folder",
        "Open a specific file",
    }

    fzf.fzf_exec(options, {
        prompt = "Choose an action > ",
        actions = {
            ["default"] = function(selected)
                if selected[1] == "Open the newest VL file" then
                    local newest_file = get_newest_vl_file(files)
                    vim.cmd("edit " .. newest_file)
                elseif selected[1] == "Create a new VL" then
                    create_new_vl(course)
                elseif selected[1] == "Open the course folder" then
                    vim.cmd("edit " .. course.path)
                elseif selected[1] == "Open a specific file" then
                    fzf.fzf_exec(fn.glob(course.path .. "/*", true, true), {
                        prompt = "Pick a file to open > ",
                        actions = {
                            ["default"] = function(file)
                                vim.cmd("edit " .. file[1])
                            end,
                        },
                    })
                end
            end,
        },
    })
end

-- Function to get the newest VL file based on modification time
function get_newest_vl_file(files)
    local newest_file = nil
    local newest_time = 0
    for _, file in ipairs(files) do
        local stat = fn.getftime(file)
        if stat > newest_time then
            newest_time = stat
            newest_file = file
        end
    end
    return newest_file
end

-- Function to create a new VL file based on the template and incrementing the number
function create_new_vl(course)
    local vl_dir = course.path .. "/VL"
	local success, _ = pcall(function()
		vim.fn.mkdir(vl_dir)
	end)
	-- Hard coded this
    local template_path = vim.fn.expand("~/projects/university/data/template.typ")
    if fn.filereadable(template_path) == 1 then
        -- Find the latest VL number in the folder
        local latest_num = 0
        for _, file in ipairs(fn.glob(vl_dir .. "/*", true, true)) do
            if file:match(course.short .. "VL(%d+).typ$") then
                local num = tonumber(file:match(course.short .. "VL(%d+).typ$"))
                if num > latest_num then
                    latest_num = num
                end
            end
        end

        -- Create new VL file with incremented number
        local new_vl_name = string.format("%sVL%d.typ", course.short, latest_num + 1)
        local new_vl_path = vl_dir .. "/" .. new_vl_name

        -- Copy the template if it exists
        vim.fn.system({"cp", template_path, new_vl_path})

        -- Open the new VL file
        vim.cmd("edit " .. new_vl_path)
    else
        print("Template file (template.typ) not found!")
    end
end