local M = {}

function M.safe_require(name)
  local ok, mod = pcall(require, name)
  if ok then return mod end
  return nil
end

-- Number of parent directories to show in full in the tabline
-- The rest will be shortened according to tabline_shorten_length
-- Example: with full_parents = 1, /path/to/my/project/src/file.txt becomes pat/to/my/project/src/file.txt
-- Example: with full_parents = 2, it becomes pat/to/my/project/src/file.txt
M.tabline_full_parents = 1

-- Number of characters to show for shortened directory names in the tabline
-- Example: with shorten_length = 3, /path/to/my becomes pat/to/my
-- Example: with shorten_length = 1, /path/to/my becomes p/t/m
M.tabline_shorten_length = 3

-- Get all modified, deleted, and untracked Git files with status
-- Returns a list suitable for setqflist() or nil on error
function M.git_changed_files()
  -- Use git status --porcelain to get all changes with status indicators
  -- Format: "XY filename" where X=index status, Y=worktree status
  -- Status codes: M=modified, D=deleted, A=added, ??=untracked, etc.
  local handle = io.popen('git status --porcelain 2>/dev/null')
  if not handle then
    vim.notify('Failed to run git status', vim.log.levels.ERROR)
    return nil
  end
  
  local result = handle:read('*a')
  handle:close()
  
  if result == '' then
    vim.notify('No git changes found', vim.log.levels.INFO)
    return nil
  end
  
  local qf_list = {}
  local status_map = {
    ['M'] = 'Modified',
    ['A'] = 'Added',
    ['D'] = 'Deleted',
    ['R'] = 'Renamed',
    ['C'] = 'Copied',
    ['U'] = 'Unmerged',
    ['?'] = 'Untracked',
  }
  
  for line in result:gmatch('[^\n]+') do
    -- Parse porcelain format: "XY filename" or "XY original -> renamed"
    local index_status = line:sub(1, 1)
    local work_status = line:sub(2, 2)
    local filename = line:sub(4) -- Skip "XY " prefix
    
    -- Determine status text (worktree takes precedence over index)
    local status_code = work_status ~= ' ' and work_status or index_status
    local status_text = status_map[status_code] or 'Changed'
    
    table.insert(qf_list, {
      filename = filename,
      lnum = 1,
      text = status_text,
    })
  end
  
  return qf_list
end

-- Custom tabline function
-- Shows configurable number of full parent directories, shortens the rest
function M.custom_tabline()
  local tabline = ''
  local num_tabs = vim.fn.tabpagenr('$')
  
  for i = 1, num_tabs do
    local buflist = vim.fn.tabpagebuflist(i)
    local winnr = vim.fn.tabpagewinnr(i)
    local bufnr = buflist[winnr]
    local bufname = vim.fn.bufname(bufnr)
    local bufmodified = vim.fn.getbufvar(bufnr, "&modified")
    
    -- Highlight for the tab
    if i == vim.fn.tabpagenr() then
      tabline = tabline .. '%#TabLineSel#'
    else
      tabline = tabline .. '%#TabLine#'
    end
    
    -- Tab number
    tabline = tabline .. ' ' .. i .. ' '
    
    -- Format the filename with smart path shortening
    local filename
    if bufname == '' then
      filename = '[No Name]'
    else
      -- Get the full path relative to cwd if possible
      local path = vim.fn.fnamemodify(bufname, ':~:.')
      
      -- Split path into components
      local parts = vim.split(path, '/', { plain = true })
      
      if #parts > M.tabline_full_parents + 1 then
        -- We have enough parts to do smart shortening
        local result = {}
        
        -- Shorten the leading directories (all but the last full_parents + filename)
        local num_to_shorten = #parts - M.tabline_full_parents - 1
        for j = 1, num_to_shorten do
          table.insert(result, parts[j]:sub(1, M.tabline_shorten_length))
        end
        
        -- Add the full parent directories
        for j = num_to_shorten + 1, #parts - 1 do
          table.insert(result, parts[j])
        end
        
        -- Add the filename
        table.insert(result, parts[#parts])
        
        filename = table.concat(result, '/')
      else
        -- Path is short enough, just use it as-is
        filename = path
      end
    end
    
    -- Add modified flag
    if bufmodified == 1 then
      filename = filename .. ' [+]'
    end
    
    tabline = tabline .. filename .. ' '
  end
  
  -- Fill the rest with TabLineFill
  tabline = tabline .. '%#TabLineFill#%T'
  
  -- Right-align: show tab page count if more than one tab
  if num_tabs > 1 then
    tabline = tabline .. '%=%#TabLine# ' .. num_tabs .. ' tabs '
  end
  
  return tabline
end

return M