-- Attribute block toggle - Interactive expand/collapse of {...} blocks
local M = {}

-- Store expanded content per buffer
-- Format: { [bufnr] = { [line_num] = { collapsed = "...", expanded = "actual content", is_collapsed = boolean } } }
local buffer_attr_state = {}

-- Find attribute block under cursor
-- Returns: start_col, end_col, content (or nil if not found)
function M.find_attr_block_under_cursor()
  local line = vim.api.nvim_get_current_line()
  local col = vim.api.nvim_win_get_cursor(0)[2] + 1 -- 1-indexed
  
  -- Find all {...} blocks in the line
  local pos = 1
  while pos <= #line do
    local start_pos, end_pos = line:find("{(.-)}", pos)
    if not start_pos then
      break
    end
    
    -- Check if cursor is within this block (including braces)
    if col >= start_pos and col <= end_pos then
      local content = line:sub(start_pos + 1, end_pos - 1)
      return start_pos, end_pos, content
    end
    
    pos = end_pos + 1
  end
  
  return nil, nil, nil
end

-- Toggle the attribute block under cursor
function M.toggle_attr_block()
  local bufnr = vim.api.nvim_get_current_buf()
  local line_num = vim.api.nvim_win_get_cursor(0)[1]
  local line = vim.api.nvim_get_current_line()
  
  local start_col, end_col, content = M.find_attr_block_under_cursor()
  if not start_col then
    vim.notify("No attribute block found under cursor", vim.log.levels.WARN)
    return
  end
  
  -- Initialize buffer state if needed
  if not buffer_attr_state[bufnr] then
    buffer_attr_state[bufnr] = {}
  end
  
  local state_key = line_num .. "_" .. start_col
  local state = buffer_attr_state[bufnr][state_key]
  
  -- Check if this is currently collapsed
  local is_collapsed = content == "..."
  
  if is_collapsed then
    -- Expand: restore original content
    if state and state.expanded then
      local new_line = line:sub(1, start_col) .. state.expanded .. line:sub(end_col)
      vim.api.nvim_set_current_line(new_line)
      buffer_attr_state[bufnr][state_key].is_collapsed = false
      vim.notify("Attribute block expanded", vim.log.levels.INFO)
    else
      vim.notify("Cannot expand: original content not stored", vim.log.levels.WARN)
    end
  else
    -- Collapse: store original and show {...}
    local new_line = line:sub(1, start_col) .. "..." .. line:sub(end_col)
    vim.api.nvim_set_current_line(new_line)
    buffer_attr_state[bufnr][state_key] = {
      collapsed = "...",
      expanded = content,
      is_collapsed = true,
      line_num = line_num,
      start_col = start_col,
    }
    vim.notify("Attribute block collapsed", vim.log.levels.INFO)
  end
end

-- Expand all collapsed blocks in current buffer
function M.expand_all_attr_blocks(opts)
  opts = opts or {}
  local bufnr = vim.api.nvim_get_current_buf()
  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
  local count = 0
  
  if not buffer_attr_state[bufnr] then
    if not opts.silent then
      vim.notify("No collapsed blocks to expand", vim.log.levels.INFO)
    end
    return
  end
  
  for state_key, state in pairs(buffer_attr_state[bufnr]) do
    if state.is_collapsed then
      local line = lines[state.line_num]
      
      if line then
        local new_line = line:sub(1, state.start_col) .. state.expanded .. line:sub(state.start_col + 4)
        lines[state.line_num] = new_line
        state.is_collapsed = false
        count = count + 1
      end
    end
  end
  
  vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
  if not opts.silent and count > 0 then
    vim.notify("Expanded " .. count .. " attribute block(s)", vim.log.levels.INFO)
  end
end

-- Find the last line of the declaration section based on filetype
local function get_declaration_end(lines, ft)
  if ft == "udt" then
    return #lines
  end
  for i, line in ipairs(lines) do
    if line:match("^%s*BEGIN%s*$") then
      return i - 1
    end
  end
  return #lines
end

-- Collapse all {...} blocks in the declaration section of current buffer
function M.collapse_all_attr_blocks()
  local bufnr = vim.api.nvim_get_current_buf()
  local ft = vim.bo[bufnr].filetype
  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
  local count = 0

  local decl_end = get_declaration_end(lines, ft)

  if not buffer_attr_state[bufnr] then
    buffer_attr_state[bufnr] = {}
  end

  for line_idx = 1, decl_end do
    local line = lines[line_idx]
    local pos = 1
    while pos <= #line do
      local start_pos, end_pos = line:find("{(.-)}", pos)
      if not start_pos then
        break
      end

      local content = line:sub(start_pos + 1, end_pos - 1)

      if content ~= "..." then
        local state_key = line_idx .. "_" .. start_pos
        buffer_attr_state[bufnr][state_key] = {
          collapsed = "...",
          expanded = content,
          is_collapsed = true,
          line_num = line_idx,
          start_col = start_pos,
        }

        line = line:sub(1, start_pos) .. "..." .. line:sub(end_pos)
        count = count + 1
        pos = start_pos + 4
      else
        pos = end_pos + 1
      end
    end
    lines[line_idx] = line
  end

  vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
  vim.notify("Collapsed " .. count .. " attribute block(s)", vim.log.levels.INFO)
end

-- Clear state when buffer is unloaded
function M.clear_buffer_state(bufnr)
  buffer_attr_state[bufnr] = nil
end

-- Setup autocmd to clear state on buffer unload
function M.setup()
  local augroup = vim.api.nvim_create_augroup("SCLAttrToggle", { clear = true })
  
  vim.api.nvim_create_autocmd("BufWritePre", {
    group = augroup,
    pattern = { "*.scl", "*.udt", "*.db" },
    callback = function(args)
      if buffer_attr_state[args.buf] then
        local has_collapsed = false
        for _, state in pairs(buffer_attr_state[args.buf]) do
          if state.is_collapsed then
            has_collapsed = true
            break
          end
        end
        if has_collapsed then
          M.expand_all_attr_blocks({ silent = true })
        end
      end
    end,
  })
  
  vim.api.nvim_create_autocmd("BufUnload", {
    group = augroup,
    pattern = { "*.scl", "*.udt", "*.db" },
    callback = function(args)
      M.clear_buffer_state(args.buf)
    end,
  })
  
  -- Create commands
  vim.api.nvim_create_user_command("SCLToggleAttrBlock", function()
    M.toggle_attr_block()
  end, {})
  
  vim.api.nvim_create_user_command("SCLExpandAllAttrBlocks", function()
    M.expand_all_attr_blocks()
  end, {})
  
  vim.api.nvim_create_user_command("SCLCollapseAllAttrBlocks", function()
    M.collapse_all_attr_blocks()
  end, {})
end

return M