-------------------------------------------------------------------------------
-- Tools to deal with tasks
-------------------------------------------------------------------------------
local Tasks = {}
local Configuration = require('configuration')
local api = vim.api
-------------------------------------------------------------------------------
-- Internal Functions
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
-- Public Interface
-------------------------------------------------------------------------------

--- Toggles a task completion status
function Tasks.toggle()
    local line_number = api.nvim_win_get_cursor(0)[1]
    local line = api.nvim_get_current_line()

    local unchecked_pattern = '^(%s*)%- %[ %]'
    local unchecked_important_pattern = '^(%s*)%* %[ %]'
    local checked_pattern = '^(%s*)%- %[x%]'
    local checked_important_pattern = '^(%s*)%* %[x%]'

    if line:match(unchecked_pattern) then
        line = line:gsub(unchecked_pattern, '%1- [x]', 1)
    elseif line:match(unchecked_important_pattern) then
        line = line:gsub(unchecked_important_pattern, '%1* [x]', 1)
    elseif line:match(checked_pattern) then
        line = line:gsub(checked_pattern, '%1- [ ]', 1)
    elseif line:match(checked_important_pattern) then
        line = line:gsub(checked_important_pattern, '%1* [ ]', 1)
    end

    api.nvim_buf_set_lines(0, line_number - 1, line_number, false, {line})
end

--- Toggles a task completion status
function Tasks.toggle_importance()
    local line_number = api.nvim_win_get_cursor(0)[1]
    local line = api.nvim_get_current_line()

    local unchecked_pattern = '^(%s*)%- %[ %]'
    local unchecked_important_pattern = '^(%s*)%* %[ %]'
    local checked_pattern = '^(%s*)%- %[x%]'
    local checked_important_pattern = '^(%s*)%* %[x%]'

    if line:match(unchecked_pattern) then
        line = line:gsub(unchecked_pattern, '%1* [ ]', 1)
    elseif line:match(unchecked_important_pattern) then
        line = line:gsub(unchecked_important_pattern, '%1- [ ]', 1)
    elseif line:match(checked_pattern) then
        line = line:gsub(checked_pattern, '%1* [x]', 1)
    elseif line:match(checked_important_pattern) then
        line = line:gsub(checked_important_pattern, '%1- [x]', 1)
    end

    api.nvim_buf_set_lines(0, line_number - 1, line_number, false, {line})
end

--- Inserts a new task at the cursor location
function Tasks.insert()
  vim.cmd('normal! o- [ ] ')
  vim.cmd('startinsert!')
end

--- Captures a new task into the inbox
function Tasks.capture()
  error('Not yet implemented')
end

--- Tag a task
function Tasks.tag()
  error('Not yet implemented')
end

--- Reschedule a task for today
function Tasks.reschedule_for_today()
  error('Not yet implemented')
end

--- Reschedule a task for tomorrow
function Tasks.reschedule_for_tomorrow()
  error('Not yet implemented')
end

--- Reschedule a task for someday
function Tasks.reschedule_for_someday()
  error('Not yet implemented')
end

--- Reschedule a task for an arbitrary date
function Tasks.reschedule(new_date)
  error('Not yet implemented')
end

return Tasks