---Debug logging facade.
---Provides dbg(), dbg.kind(), dbg.toggle(), dbg.get() and user commands.
---All debug output goes to the JSONL file at stdpath('state')/bugabinga_config_debug.jsonl.
local file = require 'std.dbg.file'
local format = require 'std.dbg.format'
local user_command = require 'std.user_command'
local viewer = require 'std.dbg.viewer'

if vim.g.bugabinga_debug_mode == nil then
	vim.g.bugabinga_debug_mode = false
end

---Returns whether debug mode is currently enabled.
---@return boolean
local function is_debug_mode()
	return vim.g.bugabinga_debug_mode
end

---Toggles debug mode on/off and prints a notification.
local function toggle_debug_mode()
	vim.g.bugabinga_debug_mode = not vim.g.bugabinga_debug_mode
	vim.notify( 'Toggled debug mode to ' .. tostring( is_debug_mode() ) )
end

---Logs a debug event of the specified kind.
---Writes to the debug JSONL file if debug mode is enabled.
---@param kind_name string DEBUG, TRACE, or ERROR
---@param message string format string with {} or {N} placeholders
---@param ... any values to substitute into the format string
local function print_debug_kind( kind_name, message, ... )
	if not is_debug_mode() then
		return
	end
	local now = os.time()
	local user_data = { ... }
	local message = format( message, user_data )
	local filename, function_name, line_number = file.get_context()
	local event = {
		kind = kind_name,
		date = now,
		message = message,
		data = user_data,
		filename = filename,
		fn = function_name,
		line = line_number,
	}
	file.write( event, file.get_path() )
end

---Logs a DEBUG event.
---@param _ any ignored (table receiver when called via metatable)
---@param message string format string with {} or {N} placeholders
---@param ... any values to substitute
local function print_debug( _, message, ... )
	if not is_debug_mode() then
		return
	end
	print_debug_kind( 'DEBUG', message, ... )
end

---Opens or closes the debug viewer depending on current state.
local function toggle_debug_viewer()
	if viewer.is_open() then
		viewer.close()
	else
		viewer.open()
	end
end

---Opens the raw JSONL debug file in a normal buffer.
local function open_raw_debug_file()
	vim.cmd.edit( file.get_path() )
end

user_command.DbgModeToggle 'Toggle global vim config debug mode.' ( toggle_debug_mode )
user_command.DbgViewToggle 'Open or close the debug event viewer' ( toggle_debug_viewer )
user_command.DbgOpenFile 'Opens the JSON debug file in normal buffer' ( open_raw_debug_file )
user_command.DbgClear 'Clears the JSON debug file' ( file.clear_log )

return setmetatable(
	{
		kind = print_debug_kind,
		toggle = toggle_debug_mode,
		get = is_debug_mode,
	},
	{
		__call = print_debug,
		__newindex = function ( ... )
			error( 'Assignments are not supported for std.dbg.\n' .. vim.inspect( ... ), 2 )
		end,
	}
)