feat: add support for Termux (#45)

* feat(parsers): move all parsers to their own submodule (#43)

BREAKING CHANGE: Parser modules have been moved

Add `check` functions to all parser modules

* fix: Termux compatible `is_readable_directory` function (#42)

* feat(util): use test command to check directory

* fix: use single quotes in util/file.lua

* feat(util): add type hints and documentation, remove old function

* feat(parsers): move all parsers to their own submodule (#43)

BREAKING CHANGE: Parser modules have been moved

Add `check` functions to all parser modules

* feat(util): use old "readable directory" method when not in Termux

* feat(parsers): add termux-api parser

* fix(parsers/termux-api): use correct field on status json

lua/battery/parsers/init.lua

@@ -10,6 +10,7 @@ M.parsers = {
   pmset = require('battery.parsers.pmset'),
   powersupply = require('battery.parsers.powersupply'),
   acpi = require('battery.parsers.acpi'),
+  termux_api = require('battery.parsers.termux-api'),
 }
 
 return M

lua/battery/parsers/termux-api.lua

@@ -0,0 +1,43 @@
+-- Getting battery info with termux-battery-status. Requires Termux and Termux:API.
+local M = {}
+
+local J = require('plenary.job')
+local L = require('plenary.log')
+
+local log = L.new({ plugin = 'battery' })
+
+local function parse_termux_battery_info(result, battery_status)
+  local status = vim.json.decode(table.concat(result, ''))
+  log.debug(vim.inspect(status))
+
+  battery_status.percent_charge_remaining = status.percentage
+  battery_status.battery_count = 1 -- WARN: This might not always be true
+  battery_status.ac_power = status.plugged:find("^PLUGGED_") -- String starts with "PLUGGED_"
+  log.debug(vim.inspect(battery_status))
+end
+
+-- Create a plenary job to get the battery info
+-- battery_status is a table to store the results in
+function M.get_battery_info_job(battery_status)
+  return J:new({
+    command = 'termux-battery-status',
+    on_exit = function(r, return_value)
+      if return_value == 0 then
+        parse_termux_battery_info(r:result(), battery_status)
+        log.debug(vim.inspect(battery_status))
+      else
+        vim.schedule(function()
+          vim.notify('battery.nvim: Error getting battery info with termux-battery-status', vim.log.levels.ERROR)
+        end)
+      end
+    end,
+  })
+end
+
+---Check if this parser would work in the current environment
+---@return boolean
+function M.check()
+  return vim.fn.executable('termux-battery-status') == 1
+end
+
+return M