-- blink.cmp completion source for SCL
-- Provides completion for UDT types, members, and variables

local M = {}

function M.new(opts)
  return setmetatable({ opts = opts or {} }, { __index = M })
end

function M:get_trigger_characters()
  return { ".", "(", "#", " ", '"' }
end

function M.is_available(context)
  local ft = vim.bo[context.bufnr].filetype
  if ft ~= "scl" and ft ~= "udt" then
    return false
  end
  
  -- Get current line directly from buffer
  local cursor = vim.api.nvim_win_get_cursor(0)
  local row = cursor[1]
  local col = cursor[2]
  local line = vim.api.nvim_buf_get_lines(context.bufnr, row - 1, row, false)[1] or ""
  
  -- Don't trigger on empty line (entering insert mode with o, i, etc.)
  if line == "" or line:match("^%s*$") then
    return false
  end
  
  -- Trigger on specific characters
  if col > 0 then
    local char_at = line:sub(col, col)
    local prev_char = col > 1 and line:sub(col - 1, col - 1) or ""
    
    -- Only trigger on our specific characters (including space for := assignments)
    if char_at == "." or char_at == "(" or char_at == "#" or char_at == '"' or char_at == " " or char_at == ":" or
       prev_char == "." or prev_char == "(" or prev_char == "#" or prev_char == '"' or prev_char == " " or prev_char == ":" then
      return true
    end
    
    -- Also trigger when typing a word character if we're in VAR section (type declaration)
    if char_at:match("[%w_]") or prev_char:match("[%w_]") then
      -- Check if we're in VAR section
      local in_var = false
      local lines = vim.api.nvim_buf_get_lines(context.bufnr, 0, row, false)
      for i = 1, #lines do
        local l = lines[i]:gsub("^%s+", ""):gsub("%s+$", "")
        if l:match("^END_VAR") then
          in_var = false
        elseif l:match("^VAR%s*$") or l:match("^VAR$") or l:match("^VAR_INPUT") or l:match("^VAR_OUTPUT") or l:match("^VAR_IN_OUT") or l:match("^VAR_TEMP") then
          in_var = true
        end
      end
      
      -- Also check current line - if it has ":" followed by space or word, we're declaring a type
      local line_before = col > 1 and line:sub(1, col - 1) or ""
      if in_var and (line_before:match(":%s*$") or line_before:match(":%s+$")) then
        return true
      end
    end
  end
  
  return false
end

function M.get_completion_types()
  return { "syntax", "words", "line", "trigger" }
end

-- Check if we're after BEGIN keyword
local function is_after_begin(bufnr)
  local cursor_row = vim.api.nvim_buf_get_mark(bufnr, ".")[1] - 1

  for i = cursor_row, 0, -1 do
    local line = vim.api.nvim_buf_get_lines(bufnr, i, i + 1, false)[1] or ""
    if line:match("^%s*BEGIN%s*$") or line:match("^%s*BEGIN%s*;") then
      return true
    end
    if line:match("^%s*ORGANIZATION_BLOCK%s+") or
       line:match("^%s*FUNCTION_BLOCK%s+") or
       line:match("^%s*FUNCTION%s+") then
      return false
    end
  end
  return false
end

-- Check if we're inside a VAR declaration section
local function is_in_var_section(bufnr)
  local cursor_row = vim.api.nvim_buf_get_mark(bufnr, ".")[1] - 1
  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, cursor_row + 1, false)
  local in_var = false
  for i = 1, cursor_row + 1 do
    local line = lines[i] or ""
    if line:match("^%s*VAR") then
      in_var = true
    elseif line:match("^%s*END_VAR") then
      in_var = false
    end
  end
  return in_var
end

-- Get all known local variables
local function get_known_variables(bufnr)
  local scl_vars = require("tia.variables")
  local variables = scl_vars.extract_variables(bufnr)
  local known = {}
  for _, v in ipairs(variables) do
    known[v.name] = true
  end
  return known
end

-- Check if a type is an FB/Function and get its interface
local function get_fb_interface(var_type)
  local fb_parser = require("tia.fb_parser")
  local clean_type = var_type:gsub('"', '')
  
  -- If cache is empty, try to scan workspace for FBs
  if fb_parser.get_cache_count() == 0 then
    local ws = require("tia.workspace_types")
    ws.scan_project_fbs(vim.api.nvim_get_current_buf())
  end
  
  return fb_parser.get_fb_interface(clean_type)
end

-- Check if a type is an FB/Function
local function is_fb_type(var_type)
  local fb_parser = require("tia.fb_parser")
  local clean_type = var_type:gsub('"', '')
  
  -- If cache is empty, try to scan workspace for FBs
  if fb_parser.get_cache_count() == 0 then
    local ws = require("tia.workspace_types")
    ws.scan_project_fbs(vim.api.nvim_get_current_buf())
  end
  
  return fb_parser.is_fb_type(clean_type)
end

function M:get_completions(context, callback)
  local bufnr = context.bufnr
  local line = context.line
  local cursor = context.cursor
  local col = cursor[2] or cursor[1] or 0

  -- Check context for FB parameter completion
  -- We want to show FB params when:
  -- - Just opened paren: fbName(
  -- - After a comma: fbName(param1 := ,
  -- - At start of parameter: fbName(param (before :)
  -- 
  -- We DON'T want to show FB params when:
  -- - After := or => with an existing value: fbName(param1 := myVar
  -- - After := or => with trailing value: fbName(param1 := value,

  local line_before_cursor = line:sub(1, col)
  
  -- Check if we're after a comma (ready for next parameter)
  local is_after_comma = line_before_cursor:match(",%s*$") ~= nil
  
  -- Check if we're typing a parameter value (after := or => with content)
  -- This is true if we have ":= something" or "=> something" without a comma after
  local has_param_assignment = line:match("%w+%s*:=%s*%S") ~= nil or line:match("%w+%s*=>%s*%S") ~= nil
  
  -- If we have a param assignment but NOT after a comma, we're typing a value
  local is_after_param_assignment = has_param_assignment and not is_after_comma

  -- Check filetype
  local ft = vim.bo[bufnr].filetype
  if ft ~= "scl" and ft ~= "udt" then
    callback({ items = {} })
    return
  end

  -- Check for Global DB completion (quoted DB names like "HmiData")
  local trimmed = line:gsub("^%s+", ""):gsub("%s+$", "")

  -- Find the "active portion" of the line - after the last operator if present
  -- Operators: :=, =>, =, <>, >=, <=, >, <, AND, OR, NOT
  -- This ensures we match DB patterns nearest to the cursor, not the first in line
  local active_portion = line_before_cursor
  
  local function find_last_operator_pos(text)
    local last_pos = 0
    local operators = {":=", "=>", "<>", ">=", "<=", "=", ">", "<"}
    for _, op in ipairs(operators) do
      local search_start = 1
      while true do
        local pos = text:find(op, search_start, true)
        if not pos then break end
        if pos > last_pos then
          last_pos = pos + #op
        end
        search_start = pos + 1
      end
    end
    -- Also check for AND/OR/NOT keywords (case insensitive)
    local keywords = {"%sAND%s", "%sOR%s", "%sNOT%s"}
    for _, kw in ipairs(keywords) do
      local search_start = 1
      while true do
        local pos = text:upper():find(kw, search_start)
        if not pos then break end
        if pos > last_pos then
          last_pos = pos + #kw - 1
        end
        search_start = pos + 1
      end
    end
    return last_pos
  end
  
  local last_op_pos = find_last_operator_pos(line_before_cursor)
  if last_op_pos > 0 then
    active_portion = line_before_cursor:sub(last_op_pos):gsub("^%s+", "")
  end

  -- Check for "DBName" pattern (quoted DB name access with dot) - in active portion only
  local db_member_pattern = active_portion:match('"([%w_]+)"%.([%w_.]*)')
  
  -- Check if we're typing a quoted DB name (after " but before closing ") - in active portion
  local is_in_db_name = active_portion:match('"[%w_]*$') ~= nil
  
  -- Check for partial DB name like "HmiData (unclosed quote) - in active portion
  local partial_db_match = active_portion:match('"([%w_]+)$')
  local is_partial_db = partial_db_match ~= nil and active_portion:match('"[^"]*$') ~= nil
  
  -- Check if after a colon followed by quote (type declaration context) - use full trimmed line
  local is_after_colon_quote = trimmed:match(':%s*"$') ~= nil
  
  -- Check if cursor is right after a closed quoted DB name (before dot) - in active portion
  local after_closed_db = active_portion:match('"([%w_]+)"%s*%.') ~= nil
  
  if db_member_pattern or after_closed_db then
    local db_parser = require("tia.db_parser")
    local db_name = active_portion:match('"([%w_]+)"')
    
    -- Ensure cache is populated
    if db_name and db_parser.get_cache_count() == 0 then
      local ws = require("tia.workspace_types")
      ws.scan_project_dbs(bufnr)
    end
    
    if db_name then
      local db = db_parser.get_db(db_name)
      if db then
        local path = active_portion:match('"[^"]+"%.([%w_.]*)$')
        
        -- Resolve nested path through DB members
        local current_type = nil
        local current_members = db_parser.get_db_members(db_name)
        local resolved_path = ""
        
        if path and path ~= "" then
          -- Parse the path parts
          local path_parts = {}
          for part in path:gmatch("[^.]+") do
            table.insert(path_parts, part)
          end
          
          -- Resolve each part of the path
          local found = true
          for i, part in ipairs(path_parts) do
            local found_member = nil
            for _, m in ipairs(current_members) do
              if m.name == part then
                found_member = m
                break
              end
            end
            
            if found_member then
              resolved_path = part
              local nested_type = nil
              if found_member.is_udt then
                nested_type = found_member.type
              else
                -- Check for array of UDT: Array[..] of "TypeName"
                local array_udt = found_member.raw_type:match('Array%b[]%s*of%s*"([^"]+)"')
                if array_udt then
                  nested_type = array_udt
                end
              end
              if nested_type then
                local udt_parser = require("tia.udt_parser")
                current_members = udt_parser.get_udt_members(nested_type)
                current_type = nested_type
              else
                -- This is a basic type, can't continue
                if i < #path_parts then
                  found = false
                  break
                end
                current_type = found_member.type
                current_members = {}
              end
            else
              found = false
              break
            end
          end
          
          if not found then
            callback({ items = {}, is_incomplete_backward = false, is_incomplete_forward = false })
            return
          end
        end
        
        -- If we have a resolved path and it's not complete (ends with .), show next level members
        if path and path ~= "" and path:match("%.$") then
          -- User wants members of the last type
        elseif path and path ~= "" and not path:match("%.$") then
          callback({ items = {}, is_incomplete_backward = false, is_incomplete_forward = false })
          return
        end
        
        -- Get members to show (either from DB or from resolved UDT type)
        if current_type then
          local udt_parser = require("tia.udt_parser")
          current_members = udt_parser.get_udt_members(current_type)
        end
        
        if #current_members > 0 then
          local items = {}
          for _, m in ipairs(current_members) do
            table.insert(items, {
              label = m.name,
              kind = m.is_udt and vim.lsp.protocol.CompletionItemKind.Struct or vim.lsp.protocol.CompletionItemKind.Field,
              detail = m.raw_type,
            })
          end
          callback({
            items = items,
            is_incomplete_backward = false,
            is_incomplete_forward = false,
          })
          return
        end
      end
    end
  end
  
  -- Check for just " pattern (start of DB name completion or partial DB name)
  if is_in_db_name or is_partial_db or is_after_colon_quote then
    local db_parser = require("tia.db_parser")
    
    -- If cache is empty, try to scan workspace for DBs
    if db_parser.get_cache_count() == 0 then
      local ws = require("tia.workspace_types")
      ws.scan_project_dbs(bufnr)
    end
    
    local db_names = db_parser.get_all_db_names()
    if #db_names > 0 then
      local items = {}
      local partial_name = partial_db_match or ""
      
      for _, name in ipairs(db_names) do
        -- Filter by partial match if user is typing
        if partial_name == "" or name:lower():find(partial_name:lower(), 1, true) == 1 then
          table.insert(items, {
            label = name,  -- Show without quotes in popup
            insertText = name,  -- Don't include quotes - user already typed opening "
            kind = vim.lsp.protocol.CompletionItemKind.Struct,
            detail = "Global DB",
            -- Custom field to identify this as a DB that needs quote wrapping
            custom = { is_global_db = true },
          })
        end
      end
      
      if #items > 0 then
        local wrapped_callback = vim.schedule_wrap(function(response)
          callback({
            items = response.items,
            is_incomplete_backward = false,
            is_incomplete_forward = false,
          })
        end)
        wrapped_callback({ items = items })
        return
      end
    end
  end

  local scl_vars = require("tia.variables")
  local variables = scl_vars.extract_variables(bufnr)

  -- Get all known local variables and their types
  local known_vars = {}
  local var_types = {}
  for _, v in ipairs(variables) do
    known_vars[v.name] = true
    var_types[v.name] = v.type
  end
  
  -- Skip FB parameter completions if user is typing a parameter value (after := or =>)
  if not is_after_param_assignment then
    -- Search for any FB call pattern in the entire line
    -- This handles cases where completion triggers before full text is typed
    local trimmed = line:gsub("^%s+", ""):gsub("%s+$", "")
  
    -- Find all potential FB calls in the line
    for fb_name in trimmed:gmatch("#?([%w_]+)%s*%(%s*%)?") do
    if known_vars[fb_name] then
      local var_type = var_types[fb_name]
      if var_type then
        local clean_type = var_type:gsub('"', '')
        if is_fb_type(clean_type) then
          local fb_interface = get_fb_interface(clean_type)
          if fb_interface then
            local wrapped_callback = vim.schedule_wrap(function(response)
              callback({
                items = response.items,
                is_incomplete_backward = false,
                is_incomplete_forward = false,
              })
            end)
            
            local items = {}
            for _, inp in ipairs(fb_interface.inputs or {}) do
              local doc_value = inp.type
              if inp.comment and inp.comment ~= "" then
                doc_value = doc_value .. "\n\n" .. inp.comment
              end
              if inp.default_value then
                doc_value = doc_value .. "\n\nDefault: " .. inp.default_value
              end
              table.insert(items, {
                label = inp.name .. " :=",
                kind = vim.lsp.protocol.CompletionItemKind.Property,
                detail = inp.type .. " (Input)",
                insertText = inp.name .. " := ",
                documentation = {
                  kind = "markdown",
                  value = doc_value,
                },
              })
            end
            for _, inout in ipairs(fb_interface.inouts or {}) do
              local doc_value = inout.type
              if inout.comment and inout.comment ~= "" then
                doc_value = doc_value .. "\n\n" .. inout.comment
              end
              if inout.default_value then
                doc_value = doc_value .. "\n\nDefault: " .. inout.default_value
              end
              table.insert(items, {
                label = inout.name .. " :=",
                kind = vim.lsp.protocol.CompletionItemKind.Property,
                detail = inout.type .. " (InOut)",
                insertText = inout.name .. " := ",
                documentation = {
                  kind = "markdown",
                  value = doc_value,
                },
              })
            end
            for _, out in ipairs(fb_interface.outputs or {}) do
              local doc_value = out.type
              if out.comment and out.comment ~= "" then
                doc_value = doc_value .. "\n\n" .. out.comment
              end
              if out.default_value then
                doc_value = doc_value .. "\n\nDefault: " .. out.default_value
              end
              table.insert(items, {
                label = out.name .. " =>",
                kind = vim.lsp.protocol.CompletionItemKind.Property,
                detail = out.type .. " (Output)",
                insertText = out.name .. " => ",
                documentation = {
                  kind = "markdown",
                  value = doc_value,
                },
              })
            end
            wrapped_callback({ items = items })
            return
          end
        end
      end
    end
  end
  end  -- if not is_after_param_assignment

  -- If no FB call found on current line, search previous lines
  -- This handles multi-line parameter completion
  -- Skip if user is typing a parameter value (after := or =>)
  if not is_after_param_assignment then
    local cursor_row = vim.api.nvim_buf_get_mark(bufnr, ".")[1] - 1
    local prev_lines = vim.api.nvim_buf_get_lines(bufnr, 0, cursor_row, false)

    -- Check if any previous line has a closed FB call (ending with ");")
    -- If so, don't provide completions
    local has_closed_call = false
    for i = 1, #prev_lines do
      if prev_lines[i]:match("%);%s*$") then
        has_closed_call = true
        break
      end
    end

    if not has_closed_call then
      for i = #prev_lines, 1, -1 do
        local prev_line = prev_lines[i]:gsub("%s+$", "")
        for fb_name in prev_line:gmatch("#?([%w_]+)%s*%(%s*%)?") do
          if known_vars[fb_name] then
            local var_type = var_types[fb_name]
            if var_type then
              local clean_type = var_type:gsub('"', '')
              if is_fb_type(clean_type) then
                local fb_interface = get_fb_interface(clean_type)
                if fb_interface then
                  local wrapped_callback = vim.schedule_wrap(function(response)
                    callback({
                      items = response.items,
                      is_incomplete_backward = false,
                      is_incomplete_forward = false,
                    })
                  end)

                  local items = {}
                  for _, inp in ipairs(fb_interface.inputs or {}) do
                    local doc_value = inp.type
                    if inp.comment and inp.comment ~= "" then
                      doc_value = doc_value .. "\n\n" .. inp.comment
                    end
                    if inp.default_value then
                      doc_value = doc_value .. "\n\nDefault: " .. inp.default_value
                    end
                    table.insert(items, {
                      label = inp.name .. " :=",
                      kind = vim.lsp.protocol.CompletionItemKind.Property,
                      detail = inp.type .. " (Input)",
                      insertText = inp.name .. " := ",
                      documentation = {
                        kind = "markdown",
                        value = doc_value,
                      },
                    })
                  end
                  for _, inout in ipairs(fb_interface.inouts or {}) do
                    local doc_value = inout.type
                    if inout.comment and inout.comment ~= "" then
                      doc_value = doc_value .. "\n\n" .. inout.comment
                    end
                    if inout.default_value then
                      doc_value = doc_value .. "\n\nDefault: " .. inout.default_value
                    end
                    table.insert(items, {
                      label = inout.name .. " :=",
                      kind = vim.lsp.protocol.CompletionItemKind.Property,
                      detail = inout.type .. " (InOut)",
                      insertText = inout.name .. " := ",
                      documentation = {
                        kind = "markdown",
                        value = doc_value,
                      },
                    })
                  end
                  for _, out in ipairs(fb_interface.outputs or {}) do
                    local doc_value = out.type
                    if out.comment and out.comment ~= "" then
                      doc_value = doc_value .. "\n\n" .. out.comment
                    end
                    if out.default_value then
                      doc_value = doc_value .. "\n\nDefault: " .. out.default_value
                    end
                    table.insert(items, {
                      label = out.name .. " =>",
                      kind = vim.lsp.protocol.CompletionItemKind.Property,
                      detail = out.type .. " (Output)",
                      insertText = out.name .. " => ",
                      documentation = {
                        kind = "markdown",
                        value = doc_value,
                      },
                    })
                  end
                  wrapped_callback({ items = items })
                  return
                end
              end
            end
          end
        end
      end
    end
  end

  local base_var = nil
  local member_path = nil

  -- Strip leading whitespace for regex matching
  local trim_line = line:gsub("^%s+", "")

  -- Note: known_vars is already defined above

  -- Function to extract base_var and member_path from a var.member... pattern
  local function extract_from_pattern(full_text)
    if not full_text then return nil, nil end

    -- Handle # prefixed
    local var_pattern = full_text:match("^#([%w_]+)")
    if var_pattern then
      local after = full_text:sub(#var_pattern + 2)
      -- Remove leading dot if present
      if after:sub(1, 1) == "." then
        after = after:sub(2)
      end
      -- Remove trailing dot if present
      if after:sub(-1) == "." then
        after = after:sub(1, -2)
      end
      return var_pattern, after
    end

    -- Non-prefixed - extract first identifier as variable
    local var_name = full_text:match("^([%w_]+)")
    if var_name and known_vars[var_name] then
      local after = full_text:sub(#var_name + 2)
      -- Remove leading dot if present
      if after:sub(1, 1) == "." then
        after = after:sub(2)
      end
      -- Remove trailing dot if present
      if after:sub(-1) == "." then
        after = after:sub(1, -2)
      end
      return var_name, after
    end

    return nil, nil
  end

  -- Find the LAST occurrence of a member access pattern (handles "AND var.member" cases)
  -- First try # prefixed patterns - handle both "#var.member" and "#var.member."
  local search_pos = 1
  while search_pos <= #trim_line do
    local hash_pos = trim_line:find("#", search_pos)
    if not hash_pos then break end
    
    -- Find the variable name after #
    local var_end = hash_pos + 1
    while var_end <= #trim_line and trim_line:sub(var_end, var_end):match("[%w_]") do
      var_end = var_end + 1
    end
    var_end = var_end - 1
    
    if var_end > hash_pos then
      local var_name = trim_line:sub(hash_pos + 1, var_end)
      -- Check if followed by a dot
      if var_end < #trim_line and trim_line:sub(var_end + 1, var_end + 1) == "." then
        -- Extract the member path after the dot
        local path_start = var_end + 2
        local path_end = path_start - 1
        while path_end < #trim_line and trim_line:sub(path_end + 1, path_end + 1):match("[%w_.]") do
          path_end = path_end + 1
        end
        local path = trim_line:sub(path_start, path_end)
        -- Remove trailing dot if present
        if path:sub(-1) == "." then
          path = path:sub(1, -2)
        end
        base_var = var_name
        member_path = path
      elseif var_end == #trim_line or trim_line:sub(var_end + 1, var_end + 1):match("[%s%)]") then
        -- Variable at end of line or followed by space/paren
        base_var = var_name
        member_path = ""
      end
    end
    search_pos = hash_pos + 1
  end

  -- Then try non-prefixed patterns - search backwards to find LAST occurrence
  if not base_var then
    local search_pos = 1
    while search_pos <= #trim_line do
      -- Find word boundaries for potential variable names
      local word_start, word_end = trim_line:find("([%w_]+)", search_pos)
      if not word_start then break end
      
      local var_name = trim_line:sub(word_start, word_end)
      if known_vars[var_name] then
        -- Check if followed by a dot
        if word_end < #trim_line and trim_line:sub(word_end + 1, word_end + 1) == "." then
          local path_start = word_end + 2
          local path_end = word_end + 1
          while path_end < #trim_line and trim_line:sub(path_end + 1, path_end + 1):match("[%w_.]") do
            path_end = path_end + 1
          end
          local path = trim_line:sub(path_start, path_end)
          if path:sub(-1) == "." then
            path = path:sub(1, -2)
          end
          base_var = var_name
          member_path = path
        elseif word_end == #trim_line then
          base_var = var_name
          member_path = ""
        end
      end
      search_pos = word_end + 1
    end
  end

  -- Fallback: just var at end of line or var followed by ( or ()
  if not base_var then
    local var_name = trim_line:match("([%w_]+)%s*%(%)$")
    if var_name and known_vars[var_name] then
      base_var = var_name
      member_path = ""
    else
      var_name = trim_line:match("([%w_]+)%s*%($")
      if var_name and known_vars[var_name] then
        base_var = var_name
        member_path = ""
      else
        var_name = trim_line:match("([%w_]+)%s*$")
        if var_name and known_vars[var_name] then
          base_var = var_name
          member_path = ""
        end
      end
    end
  end
  
  -- Also check for #varName() pattern (after auto-bracket completion)
  if not base_var then
    local hash_var = trim_line:match("#([%w_]+)%s*%(%)$")
    if hash_var and known_vars[hash_var] then
      base_var = hash_var
      member_path = ""
    end
  end
  
  -- Also check for #varName( pattern
  if not base_var then
    local hash_var = trim_line:match("#([%w_]+)%s*%($")
    if hash_var and known_vars[hash_var] then
      base_var = hash_var
      member_path = ""
    end
  end

  local wrapped_callback = vim.schedule_wrap(function(response)
    callback({
      items = response.items,
      is_incomplete_backward = false,
      is_incomplete_forward = false,
    })
  end)

  vim.schedule(function()
    local udt_parser = require("tia.udt_parser")
    local db_parser = require("tia.db_parser")

  -- No member access = show local variables, UDT types, and basic types
  if not base_var then
    local items = {}
    
    -- Add local variables from VAR sections
    local in_var_section = is_in_var_section(bufnr)
    for _, v in ipairs(variables) do
      if in_var_section then
        table.insert(items, {
          label = v.name,
          kind = vim.lsp.protocol.CompletionItemKind.Variable,
          detail = v.type and (v.type .. " - Local variable") or "Local variable",
        })
      else
        table.insert(items, {
          label = "#" .. v.name,
          insertText = "#" .. v.name,
          kind = vim.lsp.protocol.CompletionItemKind.Variable,
          detail = v.type and (v.type .. " - Local variable") or "Local variable",
        })
      end
    end
    
    -- Add UDT types
    for _, name in ipairs(udt_parser.get_all_udt_names()) do
      table.insert(items, { label = '"' .. name .. '"', kind = 14 })
    end
    
    -- Add Global DB names (without quotes - will be wrapped in resolve)
    local db_parser = require("tia.db_parser")
    if db_parser.get_cache_count() == 0 then
      local ws = require("tia.workspace_types")
      ws.scan_project_dbs(bufnr)
    end
    
    -- Check if cursor is after a quote (user typed " first)
    local line_before_cursor = line:sub(1, col)
    local is_after_quote = line_before_cursor:match('"%s*$') ~= nil
    
    for _, name in ipairs(db_parser.get_all_db_names()) do
      -- If user already typed opening quote, don't add quotes. Otherwise wrap in quotes.
      local insert_name = is_after_quote and name or '"' .. name .. '"'
      table.insert(items, {
        label = name,  -- No quotes in label
        insertText = insert_name,
        kind = vim.lsp.protocol.CompletionItemKind.Struct,
        detail = "Global DB",
      })
    end
    
    -- Add basic types - expanded list
    local basic_types = {
      -- Elementary types
      "BOOL", "BYTE", "WORD", "DWORD", "LWORD",
      "CHAR", "WCHAR", "STRING", "WSTRING",
      "INT", "DINT", "LINT", "USINT", "SINT", "UINT", "UDINT", "ULINT",
      "REAL", "LREAL",
      "TIME", "DATE", "TOD", "TIME_OF_DAY", "DATE_AND_TIME", "DT", "S5TIME", "LTIME", "DTL",
      -- Timer and counter types
      "IEC_TIMER", "TON_TIME", "TOF_TIME", "TONR_TIME", "TP_TIME",
      "IEC_TON", "IEC_TOF", "IEC_TP", "IEC_COUNTER",
      "CTU", "CTD", "CTUD",
    }
    for _, t in ipairs(basic_types) do
      table.insert(items, { label = t, kind = 19 })
    end
    
    -- Add built-in function blocks
    local builtin_fbs = {
      -- Timers and counters
      "TON", "TOF", "TP", "TONR",
      "CTU", "CTD", "CTUD",
      "IEC_TIMER", "IEC_TON", "IEC_TOF", "IEC_TP",
      "IEC_COUNTER", "IEC_CTU", "IEC_CTD", "IEC_CTUD",
      -- Bit logic
      "R_TRIG", "F_TRIG", "SR", "RS",
      -- Other
      "SCHEDULE", "BPM", "LOG", "DATALOG",
    }
    for _, fb in ipairs(builtin_fbs) do
      table.insert(items, { label = fb, kind = 6, detail = "Function block" })
    end
    
    -- Add built-in functions
    local builtin_fcs = {
      -- Math
      "ADD", "SUB", "MUL", "DIV", "MOD", "ABS", "NEG", "SQR", "SQRT",
      "EXP", "LN", "LOG", "SIN", "COS", "TAN", "ASIN", "ACOS", "ATAN",
      "MIN", "MAX", "LIMIT", "CALCULATE",
      -- Conversion
      "CONVERT", "ROUND", "TRUNC", "CEIL", "FLOOR", "SCALE_X", "NORM_X",
      "BCD_I", "I_BCD", "DI_BCD", "DI_R", "I_DI", "R_DI", "R_DB",
      -- Move/String
      "MOVE", "FILL", "SWAP", "PEEK", "POKE",
      "LEN", "CONCAT", "LEFT", "RIGHT", "MID", "INSERT", "DELETE", "REPLACE", "FIND",
      -- Bit logic
      "AND", "OR", "XOR", "NOT", "SHL", "SHR", "ROL", "ROR", "DECO", "ENCO",
      -- Time/Date
      "T_CONV", "T_ADD", "T_SUB", "T_DIFF", "T_COMBINE",
      "DT_DATE", "DT_TOD", "DATE_TO_DTL", "DTL_TO_DATE", "TOD_TO_DTL", "DTL_TO_TOD",
      "TimeToTicks", "TicksToTime",
      -- Error handling
      "GET_ERROR", "GET_ERR_ID", "RESET_ERR", "GET_DIAG", "DPRINT",
      -- Communication
      "RDREC", "WRREC", "RALRM",
      "TSEND", "TRCV", "TCON", "TDISCON", "TSEND_C", "TRCV_C",
      "TUSEND", "TURCV", "TCONNECT", "TDISCONNECT",
      "MODBUSPN", "MODBUSCP",
    }
    for _, fc in ipairs(builtin_fcs) do
      table.insert(items, { label = fc, kind = 3, detail = "Function" })
    end
    
    wrapped_callback({ items = items })
    return
  end

    -- Member completion
    local var_type = scl_vars.get_variable_type(base_var, bufnr)
    -- If base_var is not a known variable, show all local variables instead
    if not var_type then
      local items = {}
      local in_var_section = is_in_var_section(bufnr)
      for _, v in ipairs(variables) do
        if in_var_section then
          table.insert(items, {
            label = v.name,
            kind = vim.lsp.protocol.CompletionItemKind.Variable,
            detail = v.type and (v.type .. " - Local variable") or "Local variable",
          })
        else
          table.insert(items, {
            label = "#" .. v.name,
            insertText = "#" .. v.name,
            kind = vim.lsp.protocol.CompletionItemKind.Variable,
            detail = v.type and (v.type .. " - Local variable") or "Local variable",
          })
        end
      end
      for _, name in ipairs(udt_parser.get_all_udt_names()) do
        table.insert(items, { label = '"' .. name .. '"', kind = 14 })
      end
      -- Add Global DB names (without quotes - will be wrapped in resolve)
      local line_before_cursor_fallback = line:sub(1, col)
      local is_after_quote_fallback = line_before_cursor_fallback:match('"%s*$') ~= nil
      for _, name in ipairs(db_parser.get_all_db_names()) do
        local insert_name = is_after_quote_fallback and name or '"' .. name .. '"'
        table.insert(items, {
          label = name,
          insertText = insert_name,
          kind = vim.lsp.protocol.CompletionItemKind.Struct,
          detail = "Global DB",
        })
      end
      for _, t in ipairs({ "Bool", "Int", "DInt", "Real", "Word", "DWord", "Byte", "Time", "String", "SINT", "USINT", "UINT", "LREAL" }) do
        table.insert(items, { label = t, kind = 19 })
      end
      -- Add more basic types
      local more_types = { "BOOL", "DINT", "WORD", "DWORD", "LWORD", "CHAR", "WSTRING", "UDINT", "LINT", "ULINT", "USINT", "SINT", "DATE", "TOD", "DTL", "LTIME", "S5TIME", "TIME_OF_DAY", "DATE_AND_TIME" }
      for _, t in ipairs(more_types) do
        table.insert(items, { label = t, kind = 19 })
      end
      -- Add built-in FBs
      local builtin_fbs = {
        "TON", "TOF", "TP", "TONR",
        "CTU", "CTD", "CTUD",
        "IEC_TIMER", "IEC_TON", "IEC_TOF", "IEC_TP",
        "IEC_COUNTER", "IEC_CTU", "IEC_CTD", "IEC_CTUD",
        "R_TRIG", "F_TRIG", "SR", "RS",
        "SCHEDULE", "BPM", "LOG", "DATALOG",
      }
      for _, fb in ipairs(builtin_fbs) do
        table.insert(items, { label = fb, kind = 6, detail = "Function block" })
      end
      -- Add built-in functions
      local builtin_fcs = {
        "ADD", "SUB", "MUL", "DIV", "MOD", "ABS", "NEG", "SQR", "SQRT",
        "EXP", "LN", "LOG", "SIN", "COS", "TAN", "ASIN", "ACOS", "ATAN",
        "MIN", "MAX", "LIMIT", "CALCULATE",
        "CONVERT", "ROUND", "TRUNC", "CEIL", "FLOOR", "SCALE_X", "NORM_X",
        "BCD_I", "I_BCD", "DI_BCD", "DI_R", "I_DI", "R_DI", "R_DB",
        "MOVE", "FILL", "SWAP", "PEEK", "POKE",
        "LEN", "CONCAT", "LEFT", "RIGHT", "MID", "INSERT", "DELETE", "REPLACE", "FIND",
        "AND", "OR", "XOR", "NOT", "SHL", "SHR", "ROL", "ROR", "DECO", "ENCO",
        "T_CONV", "T_ADD", "T_SUB", "T_DIFF", "T_COMBINE",
        "DT_DATE", "DT_TOD", "DATE_TO_DTL", "DTL_TO_DATE", "TOD_TO_DTL", "DTL_TO_TOD",
        "GET_ERROR", "GET_ERR_ID", "RESET_ERR", "GET_DIAG", "DPRINT",
        "RDREC", "WRREC", "RALRM",
        "TSEND", "TRCV", "TCON", "TDISCON", "TSEND_C", "TRCV_C",
        "TUSEND", "TURCV", "MODBUSPN", "MODBUSCP",
      }
      for _, fc in ipairs(builtin_fcs) do
        table.insert(items, { label = fc, kind = 3, detail = "Function" })
      end
      wrapped_callback({ items = items })
      return
    end

    var_type = var_type:gsub('"', '')

    local is_udt = udt_parser.is_udt_type(var_type)
    local is_fb = is_fb_type(var_type)
    local fb_interface = nil
    
    if is_fb then
      fb_interface = get_fb_interface(var_type)
    end

    if not is_udt and not is_fb then
      -- Check built-in instructions (IEC_TIMER, TON, etc.)
      local builtin = require("tia.builtin_instructions")
      local builtin_params = builtin.get_parameters(var_type)
      if builtin_params then
        local items = {}
        for _, inp in ipairs(builtin_params.inputs or {}) do
          table.insert(items, {
            label = inp.name,
            kind = vim.lsp.protocol.CompletionItemKind.Field,
            detail = (inp.type or "ANY") .. " (Input)",
          })
        end
        for _, out in ipairs(builtin_params.outputs or {}) do
          table.insert(items, {
            label = out.name,
            kind = vim.lsp.protocol.CompletionItemKind.Field,
            detail = (out.type or "ANY") .. " (Output)",
          })
        end
        wrapped_callback({ items = items })
        return
      end
      wrapped_callback({ items = {} })
      return
    end
    
    -- Handle FB parameter completion (when user types instanceName() or instanceName(
    local line_before_cursor = line:sub(1, col)
    local is_fb_call = line_before_cursor:match("%(#?[%w_]+%s*%(%s*$") ~= nil or 
                        line_before_cursor:match("%(#?[%w_]+%s*%)%s*$") ~= nil
    
    -- Check if there's a ( somewhere after the variable (parameter call mode)
    local has_param_paren = line:match("%(") ~= nil
    
    if is_fb and fb_interface and (is_fb_call or (member_path == "" and has_param_paren)) then
      local items = {}
      for _, inp in ipairs(fb_interface.inputs or {}) do
        table.insert(items, {
          label = inp.name .. " :=",
          kind = vim.lsp.protocol.CompletionItemKind.Property,
          detail = inp.type .. " (Input)",
          insertText = inp.name .. " := ",
        })
      end
      for _, inout in ipairs(fb_interface.inouts or {}) do
        table.insert(items, {
          label = inout.name .. " :=",
          kind = vim.lsp.protocol.CompletionItemKind.Property,
          detail = inout.type .. " (InOut)",
          insertText = inout.name .. " := ",
        })
      end
      for _, out in ipairs(fb_interface.outputs or {}) do
        table.insert(items, {
          label = out.name .. " =>",
          kind = vim.lsp.protocol.CompletionItemKind.Property,
          detail = out.type .. " (Output)",
          insertText = out.name .. " => ",
        })
      end
      wrapped_callback({ items = items })
      return
    end
    
    -- Fallback: if base_var is an FB and we're after BEGIN (in code section), provide parameter completions
    if is_fb and fb_interface and member_path == "" and is_after_begin(bufnr) then
      local items = {}
      for _, inp in ipairs(fb_interface.inputs or {}) do
        table.insert(items, {
          label = inp.name .. " :=",
          kind = vim.lsp.protocol.CompletionItemKind.Property,
          detail = inp.type .. " (Input)",
          insertText = inp.name .. " := ",
        })
      end
      for _, inout in ipairs(fb_interface.inouts or {}) do
        table.insert(items, {
          label = inout.name .. " :=",
          kind = vim.lsp.protocol.CompletionItemKind.Property,
          detail = inout.type .. " (InOut)",
          insertText = inout.name .. " := ",
        })
      end
      for _, out in ipairs(fb_interface.outputs or {}) do
        table.insert(items, {
          label = out.name .. " =>",
          kind = vim.lsp.protocol.CompletionItemKind.Property,
          detail = out.type .. " (Output)",
          insertText = out.name .. " => ",
        })
      end
      wrapped_callback({ items = items })
      return
    end
    
    -- If it's an FB but we're accessing members with dot, treat as UDT-like completion
    if is_fb and fb_interface and member_path == "" then
      local items = {}
      for _, inp in ipairs(fb_interface.inputs or {}) do
        table.insert(items, {
          label = inp.name,
          kind = vim.lsp.protocol.CompletionItemKind.Field,
          detail = inp.type .. " (Input)",
        })
      end
      for _, inout in ipairs(fb_interface.inouts or {}) do
        table.insert(items, {
          label = inout.name,
          kind = vim.lsp.protocol.CompletionItemKind.Field,
          detail = inout.type .. " (InOut)",
        })
      end
      for _, out in ipairs(fb_interface.outputs or {}) do
        table.insert(items, {
          label = out.name,
          kind = vim.lsp.protocol.CompletionItemKind.Field,
          detail = out.type .. " (Output)",
        })
      end
      wrapped_callback({ items = items })
      return
    end

    if not is_udt then
      wrapped_callback({ items = {} })
      return
    end

    -- Resolve nested path - iterate through each part to find the target type
    local target_type = var_type
    if member_path and member_path ~= "" then
      local line_ends_with_dot = trim_line:match("%.$") ~= nil

      local path_parts = {}
      for part in member_path:gmatch("[^.]+") do
        table.insert(path_parts, part)
      end

      local current_type = var_type
      local resolved_parts = 0

      for i, part in ipairs(path_parts) do
        local udt = udt_parser.get_udt(current_type)
        if not udt then
          break
        end

        local found = false
        for _, member in ipairs(udt.members) do
          if member.name == part then
            resolved_parts = i
            if member.is_udt then
              current_type = member.type
              found = true
            else
              -- Not a UDT - if this is the last part, we found the target type
              -- Otherwise, we can't continue the path
              if i < #path_parts then
                found = false
              else
                found = true
                current_type = member.type
              end
            end
            break
          end
        end

        if not found then
          break
        end
      end

      if line_ends_with_dot or resolved_parts == #path_parts then
        target_type = current_type
      else
        wrapped_callback({ items = {} })
        return
      end
    end

    local members = udt_parser.get_udt_members(target_type)
    local items = {}
    for _, m in ipairs(members) do
      table.insert(items, {
        label = m.name,
        kind = m.is_udt and vim.lsp.protocol.CompletionItemKind.Struct or vim.lsp.protocol.CompletionItemKind.Field,
        detail = m.raw_type,
      })
    end

    wrapped_callback({ items = items })
  end)

  return function() end
end

-- Resolve callback to add # prefix for variables
function M:resolve(context, callback)
  local item = context.item
  local bufnr = context.bufnr

  -- Check if we should add # prefix
  local should_prefix = false
  if item and item.label then
    -- Only add # for variable kinds
    local var_kinds = {
      vim.lsp.protocol.CompletionItemKind.Variable,
      vim.lsp.protocol.CompletionItemKind.Parameter,
    }

    local is_var = false
    for _, kind in ipairs(var_kinds) do
      if item.kind == kind then
        is_var = true
        break
      end
    end

    if is_var then
      -- Check if we're after BEGIN and not in VAR section
      if is_after_begin(bufnr) and not is_in_var_section(bufnr) then
        -- Check if variable is in known variables list
        local known_vars = get_known_variables(bufnr)
        local var_name = item.label:gsub("^#", "")
        if known_vars[var_name] and not item.label:match("^#") then
          should_prefix = true
        end
      end
    end
  end

  if should_prefix then
    item.label = "#" .. item.label
    item.insertText = "#" .. (item.insertText or item.label)
    if item.textEdit and item.textEdit.newText then
      item.textEdit.newText = "#" .. item.textEdit.newText
    end
  end

  callback({ item = item })
end

return M