refactor(history): move message rendering into history module

Move code related to converting history messages into UI representation
from utils into history/render.lua for better code organization and
clean up the implementation.

lua/avante/history/render.lua

@@ -0,0 +1,171 @@
+local Helpers = require("avante.history.helpers")
+local Line = require("avante.ui.line")
+local Utils = require("avante.utils")
+
+local M = {}
+
+---Converts text into format suitable for UI
+---@param text string
+---@return avante.ui.Line[]
+local function text_to_lines(text)
+  local text_lines = vim.split(text, "\n")
+  local lines = {}
+  for _, text_line in ipairs(text_lines) do
+    table.insert(lines, Line:new({ { text_line } }))
+  end
+  return lines
+end
+
+---Converts "thinking" item into format suitable for UI
+---@param item AvanteLLMMessageContentItem
+---@return avante.ui.Line[]
+local function thinking_to_lines(item)
+  local text = item.thinking or item.data or ""
+  local text_lines = vim.split(text, "\n")
+  local ui_lines = {}
+  table.insert(ui_lines, Line:new({ { Utils.icon("🤔 ") .. "Thought content:" } }))
+  table.insert(ui_lines, Line:new({ { "" } }))
+  for _, text_line in ipairs(text_lines) do
+    table.insert(ui_lines, Line:new({ { "> " .. text_line } }))
+  end
+  return ui_lines
+end
+
+---Converts logs generated by a tool during execution into format suitable for UI
+---@param tool_name string
+---@param logs string[]
+---@return avante.ui.Line[]
+local function tool_logs_to_lines(tool_name, logs)
+  local ui_lines = {}
+  local num_logs = #logs
+
+  for log_idx = 1, num_logs do
+    local log_lines = vim.split(logs[log_idx]:gsub("^%[" .. tool_name .. "%]: ", "", 1), "\n")
+    local num_lines = #log_lines
+
+    for line_idx = 1, num_lines do
+      local decoration = (log_idx == num_logs and line_idx == num_lines) and "╰─ " or "│  "
+      table.insert(ui_lines, Line:new({ { decoration }, { " " .. log_lines[line_idx] } }))
+    end
+  end
+  return ui_lines
+end
+
+local STATE_TO_HL = {
+  generating = "AvanteStateSpinnerToolCalling",
+  failed = "AvanteStateSpinnerFailed",
+  succeeded = "AvanteStateSpinnerSucceeded",
+}
+
+---Converts a tool invocation into format suitable for UI
+---@param item AvanteLLMMessageContentItem
+---@param messages avante.HistoryMessage[]
+---@param logs string[]|nil
+---@return avante.ui.Line[]
+local function tool_to_lines(item, messages, logs)
+  local lines = {}
+
+  local result = Helpers.get_tool_result(item.id, messages)
+  local state
+  if not result then
+    state = "generating"
+  elseif result.is_error then
+    state = "failed"
+  else
+    state = "succeeded"
+  end
+  table.insert(
+    lines,
+    Line:new({
+      { "╭─ " },
+      { " " .. item.name .. " ", STATE_TO_HL[state] },
+      { " " .. state },
+    })
+  )
+  if logs then vim.list_extend(lines, tool_logs_to_lines(item.name, logs)) end
+  return lines
+end
+
+---Converts a message item into representation suitable for UI
+---@param item AvanteLLMMessageContentItem
+---@param message avante.HistoryMessage
+---@param messages avante.HistoryMessage[]
+---@return avante.ui.Line[]
+local function message_content_item_to_lines(item, message, messages)
+  if type(item) == "string" then
+    return text_to_lines(item)
+  elseif type(item) == "table" then
+    if item.type == "thinking" or item.type == "redacted_thinking" then
+      return thinking_to_lines(item.thinking or item.data or "")
+    elseif item.type == "text" then
+      return text_to_lines(item.text)
+    elseif item.type == "image" then
+      return { Line:new({ { "![image](" .. item.source.media_type .. ": " .. item.source.data .. ")" } }) }
+    elseif item.type == "tool_use" then
+      local ok, llm_tool = pcall(require, "avante.llm_tools." .. item.name)
+      if ok then
+        local tool_result_message = Helpers.get_tool_result_message(message, messages)
+        ---@cast llm_tool AvanteLLMTool
+        if llm_tool.on_render then
+          return llm_tool.on_render(item.input, {
+            logs = message.tool_use_logs,
+            state = message.state,
+            store = message.tool_use_store,
+            result_message = tool_result_message,
+          })
+        end
+      end
+
+      return tool_to_lines(item, messages, message.tool_use_logs)
+    end
+  end
+  return {}
+end
+
+---Converts a message into representation suitable for UI
+---@param message avante.HistoryMessage
+---@param messages avante.HistoryMessage[]
+---@return avante.ui.Line[]
+function M.message_to_lines(message, messages)
+  if message.displayed_content then return text_to_lines(message.displayed_content) end
+  local content = message.message.content
+  if type(content) == "string" then return text_to_lines(content) end
+  if vim.islist(content) then
+    local lines = {}
+    for _, item in ipairs(content) do
+      local item_lines = message_content_item_to_lines(item, message, messages)
+      lines = vim.list_extend(lines, item_lines)
+    end
+    return lines
+  end
+  return {}
+end
+
+---Converts a message item into text representation
+---@param item AvanteLLMMessageContentItem
+---@param message avante.HistoryMessage
+---@param messages avante.HistoryMessage[]
+---@return string
+local function message_content_item_to_text(item, message, messages)
+  local lines = message_content_item_to_lines(item, message, messages)
+  return vim.iter(lines):map(function(line) return tostring(line) end):join("\n")
+end
+
+---Converts a message into text representation
+---@param message avante.HistoryMessage
+---@param messages avante.HistoryMessage[]
+---@return string
+function M.message_to_text(message, messages)
+  local content = message.message.content
+  if type(content) == "string" then return content end
+  if vim.islist(content) then
+    return vim
+      .iter(content)
+      :map(function(item) return message_content_item_to_text(item, message, messages) end)
+      :filter(function(text) return text ~= "" end)
+      :join("\n")
+  end
+  return ""
+end
+
+return M