local M = {}

---@param path string
---@return table
local function get_entries(path)
	local result = {}
	local handle = vim.uv.fs_scandir(path)
	if not handle then return result end
	while true do
		local name, type = vim.uv.fs_scandir_next(handle)
		if not name then break end
		table.insert(result, {
			name = name .. (type == "directory" and "/" or ""),
			type = type,
			full_path = path .. "/" .. name,
		})
	end
	table.sort(result, function(a, b)
		if a.type == "directory" and b.type ~= "directory" then return true end
		if b.type == "directory" and a.type ~= "directory" then return false end
		return a.name < b.name
	end)
	return result
end

---@param project_root string
function M.manager(project_root)
	local templates = require("Polydev.templates")
	local width, height = math.floor(vim.o.columns * 0.40), math.floor(vim.o.lines * 0.4)
	local row, col = math.floor((vim.o.lines - height) / 3), math.floor((vim.o.columns - width) / 2)
	local content_row = row + 2
	local content_height = height - 3

	local cwd = vim.fn.getcwd()
	local current_view = {}

	local content_buf = vim.api.nvim_create_buf(false, true)
	local content_win = vim.api.nvim_open_win(content_buf, true, {
		relative = "editor",
		width = width,
		height = content_height,
		row = content_row,
		col = col,
		style = "minimal",
		border = "rounded",
	})

	local function close_all_windows()
		if vim.api.nvim_win_is_valid(content_win) then
			pcall(vim.api.nvim_win_close, content_win, true)
		end
	end

	local function update_screen()
		local root = vim.fn.expand(project_root)
		if vim.fn.isdirectory(root) == 0 then
			vim.fn.mkdir(root, "p")
		end
		local entries = get_entries(cwd)
		if not cwd:find(root, 1, true) then
			cwd = root
			entries = get_entries(cwd)
		end
		if cwd ~= root then
			table.insert(entries, 1, {
				name = "../",
				type = "directory",
				full_path = vim.fn.fnamemodify(cwd, ":h"),
				is_up = true,
			})
		end
		current_view = vim.deepcopy(entries)

		local lines = {}
		if #current_view == 0 then
			table.insert(lines, "No projects found in " .. cwd)
			table.insert(lines, "Press d to create a project, or a to add a folder.")
		else
			for i, item in ipairs(current_view) do
				table.insert(lines, string.format("%-2d | %-27s | %-6s", i, item.name, item.type))
			end
		end
		vim.api.nvim_buf_set_lines(content_buf, 0, -1, false, lines)
	end

	local function get_selected_entry()
		local win = content_win
		if not win or not vim.api.nvim_win_is_valid(win) then return end
		local row = vim.api.nvim_win_get_cursor(win)[1]
		return current_view[row], row
	end

	---@param type string
	---@param callback fun(lang: string, name: string)
	local function get_inputs(type, callback)
		vim.ui.input({ prompt = "Enter language for new " .. type .. ": " }, function(lang)
			if not lang or lang == "" then return end
			vim.ui.input({ prompt = "Enter " .. type .. " name: " }, function(name)
				if not name or name == "" then return end
				callback(lang, name)
			end)
		end)
	end

	update_screen()

	local buf = content_buf
	vim.keymap.set("n", "<ESC>", function()
		if vim.api.nvim_win_is_valid(content_win) then
			pcall(vim.api.nvim_win_close, content_win, true)
		end
	end, { buffer = buf })
	vim.keymap.set("n", "a", function ()
		vim.ui.input({ prompt = "New folder name: " }, function(input)
			if input then
				vim.fn.mkdir(cwd .. "/" .. input, "p")
				update_screen()
			end
		end)
	end, { buffer = buf })
	vim.keymap.set("n", "R", function ()
		local entry = get_selected_entry()
		if entry ~= nil and not entry.is_up then
			vim.ui.input({ prompt = "Rename: ", default = entry.name }, function(input)
				if input then
					local new_path = cwd .. "/" .. input
					vim.fn.rename(entry.full_path, new_path)
					update_screen()
				end
			end)
		end
	end, { buffer = buf })
	vim.keymap.set("n", "D", function()
		local entry = get_selected_entry()
		if entry ~= nil and not entry.is_up then
			vim.ui.input({ prompt = "Deletion of " .. entry.name .. ": (y/N) Defaults to N: " }, function(input)
				if input == "y" or input == "Y" then
					vim.fn.delete(entry.full_path, "rf")
					update_screen()
				end
			end)
		end
	end, { buffer = buf })
	vim.keymap.set("n", "%", function()
		get_inputs("file", function(lang, name)
			local file = templates.files[lang]
			if not file or not file.run then
				return print("Error: No file creation method for " .. lang)
			end
			close_all_windows()
			file.run(name)
		end)
	end, { buffer = buf })
	vim.keymap.set("n", "x", function()
		get_inputs("aux file", function(lang, name)
			close_all_windows()
			templates.extras.run(lang, name)
		end)
	end, { buffer = buf })
	vim.keymap.set("n", "d", function()
		get_inputs("project", function(lang, name)
			local project = templates.projects[lang]
			if not project or not project.run then
				return print("Error: No project creation method for " .. lang)
			end
			local opts = require("Polydev.configs").get(lang)
			local run_root = opts.project_root or project_root
			close_all_windows()
			project.run(name, run_root)
		end)
	end, { buffer = buf })
	vim.keymap.set("n", "<CR>", function()
		local entry = get_selected_entry()
		if not entry then return end

		if entry.type == "file" then
			close_all_windows()
			vim.cmd("edit " .. vim.fn.fnameescape(entry.full_path))
		elseif entry.type == "directory" then
			cwd = entry.full_path
			vim.cmd("cd " .. cwd)
			update_screen()
		else
			print("Error")
		end
	end, { buffer = buf })
end

return M