feat: add preview of tasks to task plugin

lua/custom/task/init.lua

@@ -1,4 +1,5 @@
 local M = {}
+local preview_ns = vim.api.nvim_create_namespace 'TaskPreview'
 
 M._win = nil
 M._buf = nil
@@ -15,7 +16,7 @@ local defaults = {
     auto = true,
   },
   keymaps = {
-    rerun = '<leader>rt'
+    rerun = '<leader>rt',
   },
 }
 
@@ -32,9 +33,9 @@ local function setup_global_keymaps()
 end
 
 function M.setup(opts)
-  vim.validate({
+  vim.validate {
-    opts = { opts, 'table', true }
+    opts = { opts, 'table', true },
-  })
+  }
   M._options = vim.tbl_deep_extend('force', {}, defaults, opts or {})
 
   if M._options.keymaps ~= false then
@@ -42,33 +43,49 @@ function M.setup(opts)
   end
 end
 
-local function float_size()
+local function calculate_dimensions(percent_width, percent_height)
-  local cfg = M._options.float
+  local width = math.floor(vim.o.columns * percent_width)
-  local width = math.floor(vim.o.columns * (cfg.width or 0.8))
+  local height = math.floor(vim.o.lines * percent_height)
-  local height = math.floor(vim.o.lines * (cfg.height or 0.8))
   local row = math.floor((vim.o.lines - height) / 2)
   local col = math.floor((vim.o.columns - width) / 2)
+  return width, height, row, col
+end
+
+local function float_size()
+  local cfg = M._options.float
+  local width, height, row, col = calculate_dimensions(cfg.width or 0.8, cfg.height or 0.8)
   return width, height, row, col, cfg.border or 'rounded'
 end
 
 local function scroll_to_bottom()
   vim.schedule(function()
-    pcall(vim.cmd, 'normal! G')
+    vim.cmd 'normal! G'
   end)
 end
 
+local function open_floating_win(buf, opts, enter)
+  return vim.api.nvim_open_win(
+    buf,
+    enter or false,
+    vim.tbl_extend('force', {
+      relative = 'editor',
+      style = 'minimal',
+      border = 'single',
+    }, opts or {})
+  )
+end
+
 local function create_terminal_window()
   local width, height, row, col, border = float_size()
   local buf = vim.api.nvim_create_buf(false, true)
-  local win = vim.api.nvim_open_win(buf, true, {
+  local win = open_floating_win(buf, {
-    relative = 'editor',
     row = row,
     col = col,
     width = width,
     height = height,
-    style = 'minimal',
     border = border,
-  })
+  }, true)
+
   vim.api.nvim_set_current_buf(buf)
   return buf, win
 end
@@ -82,6 +99,23 @@ local function cleanup_terminal()
   end
 end
 
+local function clean_dry_output(lines)
+  local cleaned = {}
+  for _, line in ipairs(lines) do
+    local cleaned_line = line:gsub('^task:%s+%[.-%]%s*', '')
+    table.insert(cleaned, cleaned_line)
+  end
+  return cleaned
+end
+
+local function highlight_line(buf, ns, line)
+  local content = vim.api.nvim_buf_get_lines(buf, line, line + 1, false)[1] or ''
+  vim.api.nvim_buf_set_extmark(buf, ns, line, 0, {
+    end_col = #content,
+    hl_group = 'Visual',
+  })
+end
+
 local function run_task_in_terminal(buf, task)
   local opts = {}
   if M._options.scroll.auto then
@@ -111,7 +145,7 @@ function M.execute_task(task)
 end
 
 function M.get_tasks()
-  if vim.fn.executable('task') ~= 1 then
+  if vim.fn.executable 'task' ~= 1 then
     vim.notify("'task' executable not found in PATH", vim.log.levels.ERROR)
     return {}
   end
@@ -130,7 +164,7 @@ end
 
 function M.on_choice(item)
   if not item or not item.name then
-    vim.notify('Invalid task selection', vim.log.levels.WARN)
+    vim.notify("Invalid task selection: no 'name' field", vim.log.levels.WARN)
     return
   end
   M.execute_task(item.name)
@@ -150,6 +184,99 @@ function M.open_window()
   }, M.on_choice)
 end
 
+function M.select_task_with_preview()
+  local tasks = M.get_tasks()
+  if #tasks == 0 then
+    vim.notify('No tasks available', vim.log.levels.WARN)
+    return
+  end
+
+  local total_width, total_height, row, col = calculate_dimensions(0.8, 0.6)
+  local list_width = math.floor(total_width * 0.4)
+  local preview_width = total_width - list_width - 2
+  local list_buf = vim.api.nvim_create_buf(false, true)
+  local preview_buf = vim.api.nvim_create_buf(false, true)
+
+  local lines = {}
+  for _, task in ipairs(tasks) do
+    table.insert(lines, string.format('%-20s %s', task.name, task.desc or ''))
+  end
+  vim.api.nvim_buf_set_lines(list_buf, 0, -1, false, lines)
+
+  local list_win = open_floating_win(list_buf, {
+    row = row,
+    col = col,
+    width = list_width,
+    height = total_height,
+    title = 'Tasks',
+    title_pos = 'center',
+  }, true)
+
+  local preview_win = open_floating_win(preview_buf, {
+    row = row,
+    col = col + list_width + 2,
+    width = preview_width,
+    height = total_height,
+    title = 'Preview',
+    title_pos = 'center',
+  }, false)
+
+  local current_line = 1
+  local line = current_line - 1
+  highlight_line(list_buf, preview_ns, line)
+
+  local function update_preview(index)
+    local task = tasks[index]
+    if not task then
+      return
+    end
+    local output = vim.fn.system { 'task', task.name, '--dry' }
+    local cleaned_output = clean_dry_output(vim.split(output, '\n'))
+    vim.api.nvim_buf_set_lines(preview_buf, 0, -1, false, cleaned_output)
+  end
+
+  update_preview(current_line)
+
+  vim.keymap.set('n', '<CR>', function()
+    local task = tasks[current_line]
+    if task then
+      vim.api.nvim_win_close(list_win, true)
+      vim.api.nvim_win_close(preview_win, true)
+      M.execute_task(task.name)
+    end
+  end, { buffer = list_buf })
+
+  vim.keymap.set('n', 'q', function()
+    vim.api.nvim_win_close(list_win, true)
+    vim.api.nvim_win_close(preview_win, true)
+  end, { buffer = list_buf })
+
+  vim.keymap.set('n', '<Esc>', function()
+    vim.api.nvim_win_close(list_win, true)
+    vim.api.nvim_win_close(preview_win, true)
+  end, { buffer = list_buf })
+
+  vim.keymap.set('n', 'j', function()
+    if current_line < #tasks then
+      vim.api.nvim_buf_clear_namespace(list_buf, preview_ns, 0, -1)
+      current_line = current_line + 1
+      highlight_line(list_buf, preview_ns, current_line - 1)
+      update_preview(current_line)
+      vim.api.nvim_win_set_cursor(list_win, { current_line, 0 })
+    end
+  end, { buffer = list_buf })
+
+  vim.keymap.set('n', 'k', function()
+    if current_line > 1 then
+      vim.api.nvim_buf_clear_namespace(list_buf, preview_ns, 0, -1)
+      current_line = current_line - 1
+      highlight_line(list_buf, preview_ns, current_line - 1)
+      update_preview(current_line)
+      vim.api.nvim_win_set_cursor(list_win, { current_line, 0 })
+    end
+  end, { buffer = list_buf })
+end
+
 local function complete(ArgLead, _, _)
   local matches = {}
   for _, task in ipairs(M.get_tasks()) do
@@ -165,7 +292,7 @@ vim.api.nvim_create_user_command('Task', function(input)
   if input.args ~= '' then
     M.execute_task(input.args)
   else
-    M.open_window()
+    M.select_task_with_preview()
   end
 end, { bang = true, desc = 'Run tasks defined in a Taskfile', nargs = '?', complete = complete })