make the message handling functions methods of the lspc object

Move the logging code into its own module and export the default logger.
Other modules can use the logger exported in the lspc table.

1 files changed, 64 insertions, 0 deletions

diff --git a/log.lua b/log.lua
new file mode 100644
index 0000000..c1c36a7
--- /dev/null
+++ b/log.lua
@@ -0,0 +1,64 @@
+--- Simple logging module for vis-lspc.
+-- @module log
+-- @author Florian Fischer
+-- @license GPL-3
+-- @copyright 2024 Florian Fischer
+local log = {}
+
+--- Logger class metatable.
+local Logger = {}
+function Logger:log(msg)
+  self.log_fd:write(msg)
+  self.log_fd:write('\n')
+  self.log_fd:flush()
+end
+function Logger:close()
+  self.log_fd:close()
+end
+
+--- Dummy logger class metatable using NOP log functions.
+local DummyLogger = {}
+function DummyLogger:log()
+end
+function DummyLogger:close()
+end
+
+function log.new(name, logging, log_file)
+  local logger = {name = name, log_fd = nil}
+
+  if not logging then
+    setmetatable(logger, {__index = DummyLogger})
+    return logger
+  end
+
+  setmetatable(logger, {__index = Logger})
+
+  -- open the default log file in $XDG_DATA_HOME/vis-lspc
+  if not log_file then
+    local xdg_data = os.getenv('XDG_DATA_HOME') or os.getenv('HOME') .. '/.local/share'
+    local log_dir = xdg_data .. '/vis-lspc'
+
+    -- ensure the direcoty exists
+    os.execute('mkdir -p ' .. log_dir)
+
+    -- log file format: {timestamp}-{basename-cwd}.log
+    local log_file_fmt = log_dir .. '/%s-%s.log'
+    local timestamp = os.date('%Y-%m-%dT%H:%M:%S')
+    local proc = assert(io.popen('basename "${PWD}"', 'r'))
+    local basename_cwd = assert(proc:read('*a')):match('^%s*(.-)%s*$')
+    local success, _, status = proc:close()
+    if not success then
+      local err = 'getting the basename of CWD failed with exit code: ' .. status
+      vis:info('LSPC Error: ' .. err)
+    end
+    log_file = log_file_fmt:format(timestamp, basename_cwd)
+
+  elseif type(log_file) == 'function' then
+    log_file = log_file()
+  end
+
+  logger.log_fd = assert(io.open(log_file, 'w'))
+  return logger
+end
+
+return log