--- @since 25.5.28

local M = {}

local STATE_KEY = {
	ALTER_DF_COMMAND = "ALTER_DF_COMMAND",
}

local set_state = ya.sync(function(state, key, value)
	state[key] = value
end)

local get_state = ya.sync(function(state, key)
	return state[key]
end)

local function permission(file)
	local h = file
	if not h then
		return ""
	end

	local perm = h.cha:perm()
	if not perm then
		return ""
	end

	local spans = ""
	for i = 1, #perm do
		local c = perm:sub(i, i)
		spans = spans .. c
	end
	return spans
end

local function link_count(file)
	local h = file
	if h == nil or ya.target_family() ~= "unix" then
		return ""
	end

	return h.cha.nlink
end

local function owner_group(file)
	local h = file
	if h == nil or ya.target_family() ~= "unix" then
		return ""
	end
	return (ya.user_name(h.cha.uid) or tostring(h.cha.uid)) .. "/" .. (ya.group_name(h.cha.gid) or tostring(h.cha.gid))
end

local file_size_and_folder_childs = function(file)
	local h = file
	if not h then
		return ""
	end

	return h.cha.len and ya.readable_size(h.cha.len) or ""
end

--- get file timestamp
---@param file any
---@param type "mtime" | "atime" | "btime"
---@return any
local function fileTimestamp(file, type)
	local h = file
	if not h then
		return ""
	end
	local time = math.floor(h.cha[type] or 0)
	if time == 0 then
		return ""
	else
		return os.date("%Y-%m-%d %H:%M", time)
	end
end

-- Function to split a string by spaces (considering multiple spaces as one delimiter)
local function split_by_whitespace(input)
	local result = {}
	for word in string.gmatch(input, "%S+") do
		table.insert(result, word)
	end
	return result
end

local function get_filesystem_extra(file)
	local result = {
		filesystem = "",
		device = "",
		type = "",
		used_space = "",
		avail_space = "",
		total_space = "",
		used_space_percent = "",
		avail_space_percent = "",
		error = nil,
		is_virtual = false,
	}
	local h = file
	local file_url = h.url
	local is_virtual = file_url.scheme and file_url.scheme.is_virtual
	file_url = is_virtual and (file.path or Url(file_url.scheme.cache .. tostring(file_url.path)))
		or (file_url.path or file_url.url)
	if not h or ya.target_family() ~= "unix" then
		return result
	end
	local output, child

	local alter_df_command = get_state(STATE_KEY.ALTER_DF_COMMAND)
	if not alter_df_command then
		child, _ = Command("df"):arg({ "-P", "-T", "-h", tostring(file_url) }):stdout(Command.PIPED):spawn()

		if child then
			-- Ignore header
			local _, event = child:read_line()
			if event == 0 then
				output, _ = child:read_line()
			end
			child:start_kill()
		end
	end

	-- Fallback for macOS/BSD if -T failed (empty output or error)
	if not output or output == "" then
		if not alter_df_command then
			set_state(STATE_KEY.ALTER_DF_COMMAND, true)
		end
		child, _ = Command("df"):arg({ "-P", "-h", tostring(file_url) }):stdout(Command.PIPED):spawn()
		if child then
			local _, event = child:read_line() -- skip header
			if event == 0 then
				output, _ = child:read_line()
			end
			child:start_kill()
		end
	end

	if output and output ~= "" then
		-- Splitting the data
		local parts = split_by_whitespace(output)

		-- Display the result
		if #parts >= 7 then
			result.filesystem = is_virtual and (parts[7] .. " (vfs)") or parts[7]
			result.device = is_virtual and (parts[1] .. " (vfs)") or parts[1]
			result.total_space = parts[3]
			result.used_space = parts[4]
			result.avail_space = parts[5]
			result.used_space_percent = parts[6]
			result.avail_space_percent = 100 - tonumber((string.match(parts[6], "%d+") or "0"))
			result.type = is_virtual and (parts[2] .. " (vfs)") or parts[2]
		else
			result.filesystem = is_virtual and (parts[6] .. " (vfs)") or parts[6]
			-- result.device (Type) is missing in df output, fetch from mount
			result.total_space = parts[2]
			result.used_space = parts[3]
			result.avail_space = parts[4]
			result.used_space_percent = parts[5]
			result.avail_space_percent = 100 - tonumber((string.match(parts[5], "%d+") or "0"))
			result.device = is_virtual and (parts[1] .. " (vfs)") or parts[1]

			local mount_child = Command("mount"):stdout(Command.PIPED):spawn()
			if mount_child then
				while true do
					local line, event = mount_child:read_line()
					if not line or event ~= 0 then
						break
					end
					-- Check if line starts with filesystem (e.g. /dev/disk1s1 on ...)
					local s, e = line:find(parts[1] .. " on ", 1, true)
					if s == 1 then
						local fstype = line:match("%(([^,]+)")
						if fstype then
							result.type = is_virtual and (fstype .. " (vfs)") or fstype
						end
						break
					end
				end
			end
		end
		result.is_virtual = is_virtual
	else
		result.error = "df error: check install"
	end
	return result
end

local function attributes(file)
	local h = file
	local file_url = h.url
	if h.cha.is_link then
		file_url = Url(h.link_to)
	end
	local is_virtual = file_url.scheme and file_url.scheme.is_virtual
	file_url = is_virtual and (file.path or Url(file_url.scheme.cache .. tostring(file_url.path))) or file_url

	if not h or ya.target_family() ~= "unix" then
		return ""
	end

	local output, _ = Command("lsattr"):arg({ "-d", tostring(file_url) }):stdout(Command.PIPED):output()

	if output then
		-- Splitting the data
		local parts = split_by_whitespace(output.stdout)

		-- Display the result
		for i, part in ipairs(parts) do
			if i == 1 then
				return part
			end
		end
		return ""
	else
		return "lsattr error: check install"
	end
end

---shorten string
---@param _s string string
---@param _t string tail
---@param _w number max characters
---@return string
local shorten = function(_s, _t, _w)
	local s = _s or utf8.len(_s)
	local t = _t or ""
	local ellipsis = "…" .. t
	local w = _w < utf8.len(ellipsis) and utf8.len(ellipsis) or _w
	local n_ellipsis = utf8.len(ellipsis) or 0
	if utf8.len(s) > w then
		return s:sub(1, (utf8.offset(s, w - n_ellipsis + 1) or 2) - 1) .. ellipsis
	end
	return s
end

function M:render_table(job, opts)
	local styles = {
		header = th.spot.title or ui.Style():fg("green"),
		row_label = ui.Style():fg("reset"),
		row_value = th.spot.tbl_col or ui.Style():fg("blue"),
	}
	local filesystem_extra = get_filesystem_extra(job.file)
	local prefix = "  "
	local rows = {}
	local label_max_length = 15
	local file_name_extension = job.file.cha.is_dir and "…" or ("." .. (job.file.url.ext or ""))

	local row = function(key, value)
		local h = type(value) == "table" and #value or 1
		rows[#rows + 1] = ui.Row({ ui.Line(key):style(styles.row_label), ui.Text(value):style(styles.row_value) })
			:height(h)
	end

	local file_name = shorten(
		job.file.name,
		file_name_extension,
		math.floor(job.area.w - label_max_length - utf8.len(file_name_extension))
	)
	local location = shorten(
		tostring((job.file.url.path or job.file.url).parent),
		"",
		math.floor(job.area.w - label_max_length - utf8.len(prefix))
	)
	local filesystem_error = filesystem_extra.error
			and shorten(filesystem_extra.error, "", math.floor(job.area.w - label_max_length - utf8.len(prefix)))
		or nil
	local filesystem =
		shorten(filesystem_extra.filesystem, "", math.floor(job.area.w - label_max_length - utf8.len(prefix)))

	rows[#rows + 1] = ui.Row({ "Metadata", "" }):style(styles.header)
	row(prefix .. "File:", file_name)
	row(prefix .. "Mimetype:", job.mime)
	row(prefix .. "Location:", location)
	if job.file.cache then
		row(prefix .. "Cached:", tostring(job.file.path or job.file.cache))
	end
	row(prefix .. "Mode:", permission(job.file))
	row(prefix .. "Attributes:", attributes(job.file))
	row(prefix .. "Links:", tostring(link_count(job.file)))
	if job.file.cha.is_link then
		row(prefix .. "Linked:", tostring(job.file.cha.is_link and job.file.link_to))
	end
	row(prefix .. "Owner:", owner_group(job.file))
	row(prefix .. "Size:", file_size_and_folder_childs(job.file))
	row(prefix .. "Created:", fileTimestamp(job.file, "btime"))
	row(prefix .. "Modified:", fileTimestamp(job.file, "mtime"))
	row(prefix .. "Accessed:", fileTimestamp(job.file, "atime"))
	row(prefix .. "Filesystem:", filesystem_error or filesystem)
	row(prefix .. "Device:", filesystem_error or filesystem_extra.device)
	row(prefix .. "Type:", filesystem_error or filesystem_extra.type)
	row(
		prefix .. "Free space:",
		filesystem_error
			or (
				(
						filesystem_extra.avail_space
						and filesystem_extra.total_space
						and filesystem_extra.avail_space_percent
					)
					and (filesystem_extra.avail_space .. " / " .. filesystem_extra.total_space .. " (" .. filesystem_extra.avail_space_percent .. "%)")
				or ""
			)
	)
	if opts and opts.show_plugins_section then
		-- TODO: Remove this after the next release
		local is_yazi_nightly, _ = pcall(require, "mime.dir")
		local spotter = rt.plugin.spotter(is_yazi_nightly and job.file or job.file.url, job.mime)
		local previewer = rt.plugin.previewer(is_yazi_nightly and job.file or job.file.url, job.mime)
		local fetchers = rt.plugin.fetchers(job.file, job.mime)
		local preloaders = rt.plugin.preloaders(is_yazi_nightly and job.file or job.file.url, job.mime)

		for i, v in ipairs(fetchers) do
			fetchers[i] = v.cmd
		end
		for i, v in ipairs(preloaders) do
			preloaders[i] = v.cmd
		end

		rows[#rows + 1] = ui.Row({ { "", "Plugins" }, "" }):height(2):style(styles.header)
		row(prefix .. "Spotter:", spotter and spotter.cmd or "(none)")
		row(prefix .. "Previewer:", previewer and previewer.cmd or "(none)")
		row(prefix .. "Fetchers:", #fetchers ~= 0 and fetchers or "(none)")
		row(prefix .. "Preloaders:", #preloaders ~= 0 and preloaders or "(none)")
	end

	return ui.Table(rows):area(job.area):row(1):col(1):col_style(styles.row_value):widths({
		ui.Constraint.Length(label_max_length),
		ui.Constraint.Fill(1),
	})
end

function M:peek(job)
	local start, cache = os.clock(), ya.file_cache(job)
	if not cache or not self:preload(job) then
		return 1
	end
	ya.sleep(math.max(0, rt.preview.image_delay / 1000 + start - os.clock()))
	ya.preview_widget(job, { self:render_table(job) })
end

function M:seek(job)
	local h = cx.active.current.hovered
	if h and h.url == job.file.url then
		local step = math.floor(job.units * job.area.h / 10)
		ya.emit("peek", {
			tostring(math.max(0, cx.active.preview.skip + step)),
			only_if = tostring(job.file.url),
		})
	end
end

function M:preload(job)
	local cache = ya.file_cache(job)
	if not cache or fs.cha(cache) then
		return true
	end
	return true
end

function M:spot(job)
	job.area = ui.Pos({ "center", w = 80, h = 25 })
	ya.spot_table(
		job,
		self:render_table(job, { show_plugins_section = true })
			:cell_style(th.spot.tbl_cell or ui.Style():fg("blue"):reverse())
	)
end

return M
