-- modules/fs.lua - Comprehensive filesystem utilities

local fs = {}

-- ======================================================================
-- FILE OPERATIONS
-- ======================================================================

function fs.exists(path)
	return moonshark.file_exists(path)
end

function fs.size(path)
	local size = moonshark.file_size(path)
	return size >= 0 and size or nil
end

function fs.is_dir(path)
	return moonshark.file_is_dir(path)
end

function fs.is_file(path)
	return fs.exists(path) and not fs.is_dir(path)
end

function fs.read(path)
	local content, err = moonshark.file_read(path)
	if not content then
		error("Failed to read file '" .. path .. "': " .. (err or "unknown error"))
	end
	return content
end

function fs.write(path, content)
	local success, err = moonshark.file_write(path, content)
	if not success then
		error("Failed to write file '" .. path .. "': " .. (err or "unknown error"))
	end
	return true
end

function fs.append(path, content)
	local success, err = moonshark.file_append(path, content)
	if not success then
		error("Failed to append to file '" .. path .. "': " .. (err or "unknown error"))
	end
	return true
end

function fs.copy(src, dst)
	local success, err = moonshark.file_copy(src, dst)
	if not success then
		error("Failed to copy '" .. src .. "' to '" .. dst .. "': " .. (err or "unknown error"))
	end
	return true
end

function fs.move(src, dst)
	local success, err = moonshark.file_move(src, dst)
	if not success then
		error("Failed to move '" .. src .. "' to '" .. dst .. "': " .. (err or "unknown error"))
	end
	return true
end

function fs.remove(path)
	local success, err = moonshark.file_delete(path)
	if not success then
		error("Failed to remove '" .. path .. "': " .. (err or "unknown error"))
	end
	return true
end

function fs.mtime(path)
	local timestamp = moonshark.file_mtime(path)
	return timestamp >= 0 and timestamp or nil
end

function fs.touch(path)
	local success, err = moonshark.touch(path)
	if not success then
		error("Failed to touch '" .. path .. "': " .. (err or "unknown error"))
	end
	return true
end

function fs.lines(path)
	local lines, err = moonshark.file_lines(path)
	if not lines then
		error("Failed to read lines from '" .. path .. "': " .. (err or "unknown error"))
	end
	return lines
end

-- ======================================================================
-- DIRECTORY OPERATIONS
-- ======================================================================

function fs.mkdir(path)
	local success, err = moonshark.dir_create(path)
	if not success then
		error("Failed to create directory '" .. path .. "': " .. (err or "unknown error"))
	end
	return true
end

function fs.rmdir(path)
	local success, err = moonshark.dir_remove(path)
	if not success then
		error("Failed to remove directory '" .. path .. "': " .. (err or "unknown error"))
	end
	return true
end

function fs.list(path)
	local entries, err = moonshark.dir_list(path)
	if not entries then
		error("Failed to list directory '" .. path .. "': " .. (err or "unknown error"))
	end
	return entries
end

function fs.list_files(path)
	local entries = fs.list(path)
	local files = {}
	for _, entry in ipairs(entries) do
		if not entry.is_dir then
			table.insert(files, entry)
		end
	end
	return files
end

function fs.list_dirs(path)
	local entries = fs.list(path)
	local dirs = {}
	for _, entry in ipairs(entries) do
		if entry.is_dir then
			table.insert(dirs, entry)
		end
	end
	return dirs
end

function fs.list_names(path)
	local entries = fs.list(path)
	local names = {}
	for _, entry in ipairs(entries) do
		table.insert(names, entry.name)
	end
	return names
end

-- ======================================================================
-- PATH OPERATIONS
-- ======================================================================

function fs.join(...)
	return moonshark.path_join(...)
end

function fs.dirname(path)
	return moonshark.path_dir(path)
end

function fs.basename(path)
	return moonshark.path_basename(path)
end

function fs.ext(path)
	return moonshark.path_ext(path)
end

function fs.abs(path)
	local abs_path, err = moonshark.path_abs(path)
	if not abs_path then
		error("Failed to get absolute path for '" .. path .. "': " .. (err or "unknown error"))
	end
	return abs_path
end

function fs.clean(path)
	return moonshark.path_clean(path)
end

function fs.split(path)
	return moonshark.path_split(path)
end

-- Split path into directory, name, and extension
function fs.splitext(path)
	local dir = fs.dirname(path)
	local base = fs.basename(path)
	local ext = fs.ext(path)
	local name = base
	
	if ext ~= "" then
		name = base:sub(1, -(#ext + 1))
	end
	
	return dir, name, ext
end

-- ======================================================================
-- WORKING DIRECTORY
-- ======================================================================

function fs.getcwd()
	local cwd, err = moonshark.getcwd()
	if not cwd then
		error("Failed to get current directory: " .. (err or "unknown error"))
	end
	return cwd
end

function fs.chdir(path)
	local success, err = moonshark.chdir(path)
	if not success then
		error("Failed to change directory to '" .. path .. "': " .. (err or "unknown error"))
	end
	return true
end

-- ======================================================================
-- TEMPORARY FILES
-- ======================================================================

function fs.tempfile(prefix)
	local path, err = moonshark.temp_file(prefix)
	if not path then
		error("Failed to create temporary file: " .. (err or "unknown error"))
	end
	return path
end

function fs.tempdir(prefix)
	local path, err = moonshark.temp_dir(prefix)
	if not path then
		error("Failed to create temporary directory: " .. (err or "unknown error"))
	end
	return path
end

-- ======================================================================
-- PATTERN MATCHING
-- ======================================================================

function fs.glob(pattern)
	local matches, err = moonshark.glob(pattern)
	if not matches then
		error("Failed to glob pattern '" .. pattern .. "': " .. (err or "unknown error"))
	end
	return matches
end

function fs.walk(root)
	local files, err = moonshark.walk(root)
	if not files then
		error("Failed to walk directory '" .. root .. "': " .. (err or "unknown error"))
	end
	return files
end

-- ======================================================================
-- UTILITY FUNCTIONS
-- ======================================================================

-- Get file extension without dot
function fs.extension(path)
	local ext = fs.ext(path)
	return ext:sub(2) -- Remove leading dot
end

-- Change file extension
function fs.change_ext(path, new_ext)
	local dir, name, _ = fs.splitext(path)
	if not new_ext:match("^%.") then
		new_ext = "." .. new_ext
	end
	return fs.join(dir, name .. new_ext)
end

-- Ensure directory exists
function fs.ensure_dir(path)
	if not fs.exists(path) then
		fs.mkdir(path)
	elseif not fs.is_dir(path) then
		error("Path exists but is not a directory: " .. path)
	end
	return true
end

-- Get file size in human readable format
function fs.size_human(path)
	local size = fs.size(path)
	if not size then return nil end
	
	local units = {"B", "KB", "MB", "GB", "TB"}
	local unit_index = 1
	local size_float = tonumber(size)
	
	while size_float >= 1024 and unit_index < #units do
		size_float = size_float / 1024
		unit_index = unit_index + 1
	end
	
	if unit_index == 1 then
		return string.format("%d %s", size_float, units[unit_index])
	else
		return string.format("%.1f %s", size_float, units[unit_index])
	end
end

-- Check if path is safe (doesn't contain .. or other dangerous patterns)
function fs.is_safe_path(path)
	-- Normalize path
	path = fs.clean(path)
	
	-- Check for dangerous patterns
	if path:match("%.%.") then return false end
	if path:match("^/") then return false end -- Absolute paths might be dangerous
	if path:match("^~") then return false end -- Home directory references
	
	return true
end

-- Create directory tree
function fs.makedirs(path)
	return fs.mkdir(path) -- mkdir already creates parent directories
end

-- Remove directory tree
function fs.removedirs(path)
	return fs.rmdir(path) -- rmdir already removes recursively
end

-- Copy directory tree
function fs.copytree(src, dst)
	if not fs.exists(src) then
		error("Source directory does not exist: " .. src)
	end
	
	if not fs.is_dir(src) then
		error("Source is not a directory: " .. src)
	end
	
	fs.mkdir(dst)
	
	local entries = fs.list(src)
	for _, entry in ipairs(entries) do
		local src_path = fs.join(src, entry.name)
		local dst_path = fs.join(dst, entry.name)
		
		if entry.is_dir then
			fs.copytree(src_path, dst_path)
		else
			fs.copy(src_path, dst_path)
		end
	end
	
	return true
end

-- Find files by pattern
function fs.find(root, pattern, recursive)
	recursive = recursive ~= false
	local results = {}
	
	local function search(dir)
		local entries = fs.list(dir)
		for _, entry in ipairs(entries) do
			local full_path = fs.join(dir, entry.name)
			
			if not entry.is_dir and entry.name:match(pattern) then
				table.insert(results, full_path)
			elseif entry.is_dir and recursive then
				search(full_path)
			end
		end
	end
	
	search(root)
	return results
end

-- Get directory tree as nested table
function fs.tree(root, max_depth)
	max_depth = max_depth or 10
	
	local function build_tree(path, depth)
		if depth > max_depth then return nil end
		
		if not fs.exists(path) then return nil end
		
		local node = {
			name = fs.basename(path),
			path = path,
			is_dir = fs.is_dir(path)
		}
		
		if node.is_dir then
			node.children = {}
			local entries = fs.list(path)
			for _, entry in ipairs(entries) do
				local child_path = fs.join(path, entry.name)
				local child = build_tree(child_path, depth + 1)
				if child then
					table.insert(node.children, child)
				end
			end
		else
			node.size = fs.size(path)
			node.mtime = fs.mtime(path)
		end
		
		return node
	end
	
	return build_tree(root, 1)
end

-- Monitor file changes (simplified version)
function fs.watch(path, callback, interval)
	interval = interval or 1
	
	if not fs.exists(path) then
		error("Path does not exist: " .. path)
	end
	
	local last_mtime = fs.mtime(path)
	
	while true do
		local current_mtime = fs.mtime(path)
		if current_mtime and current_mtime ~= last_mtime then
			callback(path, "modified")
			last_mtime = current_mtime
		end
		
		-- Sleep for interval (this would need a proper sleep function)
		-- This is a placeholder - real implementation would need proper timing
		local start = os.clock()
		while os.clock() - start < interval do end
	end
end

return fs