---@module 'snacks'

local log = require("javelin.log")

local Data = {}

---@type JavelinConfig
local options

local data_dir
local data_cache = {}

---@param path string
---@return string
local function hash_path(path)
	return vim.fn.sha256(vim.fn.resolve(path))
end

---@param root_path string
local function get_data_file(root_path)
	return vim.fn.resolve(data_dir .. "/" .. hash_path(root_path))
end

---@param root_path string
---@param path string
---@return string
local function normalize_path(root_path, path)
	root_path = root_path .. "/"
	if vim.startswith(path, root_path) then
		return path:sub(#root_path + 1)
	end

	return path
end

---@param root_path string
---@param list string[]
---@return string[]
local function normalize_list(root_path, list)
	local new_list = {}
	for _, path in ipairs(list) do
		if path ~= "" then
			table.insert(new_list, path)
		end
	end

	for i, path in ipairs(new_list) do
		new_list[i] = normalize_path(root_path, path)
	end

	return new_list
end

---@param root_path string
local function load(root_path)
	local data_file = get_data_file(root_path)
	if not vim.uv.fs_stat(data_file) then
		return {}
	end

	return normalize_list(root_path, vim.fn.readfile(data_file))
end

---@param root_path string
local function write(root_path)
	vim.fn.writefile(Data.get_list(root_path), get_data_file(root_path))
end

---@param root_path string
---@param path string
local function add_path(root_path, path)
	local list = Data.get_list(root_path)
	path = normalize_path(root_path, vim.fn.fnamemodify(path, ":~"))

	if vim.tbl_contains(list, path) then
		log.warn("File already in list: " .. path)
		return
	end

	table.insert(list, path)
	write(root_path)
end

---@param root_path string
---@return string[]
function Data.get_list(root_path)
	local hash = hash_path(root_path)
	if data_cache[hash] == nil then
		data_cache[hash] = load(root_path)
	end

	return data_cache[hash]
end

---@return string[]
function Data.get_current()
	return Data.get_list(Data.get_root())
end

function Data.add_current()
	local filename = vim.api.nvim_buf_get_name(0)
	local buftype = vim.api.nvim_get_option_value("buftype", { buf = 0 })

	if filename ~= "" and buftype == "" then
		add_path(Data.get_root(), filename)
	else
		log.warn("Cannot add this buffer")
	end
end

---@param root_path string
---@param lines string[]
function Data.update(root_path, lines)
	data_cache[hash_path(root_path)] = normalize_list(root_path, lines)
	write(root_path)
end

---@return string
function Data.get_root()
	local root = vim.fn.getcwd()

	if options.use_git_root then
		local git_root = Snacks.git.get_root(root)
		if git_root then
			root = git_root
		end
	end

	return vim.fn.fnamemodify(root, ":~")
end

function Data.setup(opt)
	options = opt

	data_dir = vim.fn.resolve(vim.fn.stdpath("data") .. "/javelin")
	if not vim.uv.fs_stat(data_dir) then
		vim.uv.fs_mkdir(data_dir, tonumber("755", 8))
	end
end

return Data