-- lua/chatgpt_nvim/init.lua
local M = {}

local context = require('chatgpt_nvim.context')
local handler = require('chatgpt_nvim.handler')
local config = require('chatgpt_nvim.config')

local ok_yaml, lyaml = pcall(require, "lyaml")

local function copy_to_clipboard(text)
  vim.fn.setreg('+', text)
end

local function parse_response(raw)
  if not ok_yaml then
    vim.api.nvim_err_writeln("lyaml not available. Install with `luarocks install lyaml`.")
    return nil
  end
  local ok, data = pcall(lyaml.load, raw)
  if not ok or not data then
    vim.api.nvim_err_writeln("Failed to parse YAML response.")
    return nil
  end
  return data
end

-- A simple token estimation function (approx. 4 chars per token)
local function estimate_tokens(text)
  local approx_chars_per_token = 4
  local length = #text
  return math.floor(length / approx_chars_per_token)
end

local function is_subpath(root, path)
  local root_abs = vim.fn.fnamemodify(root, ":p")
  local target_abs = vim.fn.fnamemodify(path, ":p")
  return target_abs:sub(1, #root_abs) == root_abs
end

function M.run_chatgpt_command()
  local conf = config.load()
  local user_input = vim.fn.input("Message for O1 Model: ")
  if user_input == "" then
    print("No input provided.")
    return
  end

  local dirs = conf.directories or {"."}
  local project_structure = context.get_project_structure(dirs)
  local all_files = context.get_project_files(dirs)
  local file_sections = context.get_file_contents(all_files)

  local sections = {
    conf.initial_prompt .. "\n" .. user_input,
    "\n\nProject name: " .. (conf.project_name or "") .. "\n",
    "\n\nProject Structure:\n",
    project_structure,
    "\n\nBelow are the files from the project, each preceded by its filename in backticks and enclosed in triple backticks.\n"
  }

  table.insert(sections, file_sections)

  local prompt = table.concat(sections, "\n")

  local token_limit = conf.token_limit or 8000
  local token_count = estimate_tokens(prompt)

  if token_count > token_limit then
    print("Too many files attached. The request exceeds the O1 model limit of " .. token_limit .. " tokens.")
    return
  end

  copy_to_clipboard(prompt)
  print("Prompt copied to clipboard! Paste it into the ChatGPT O1 model.")
end

function M.run_chatgpt_paste_command()
  print("Reading ChatGPT YAML response from clipboard...")
  local conf = config.load()
  local raw = handler.get_clipboard_content()
  if raw == "" then
    vim.api.nvim_err_writeln("Clipboard is empty. Please copy the YAML response from ChatGPT first.")
    return
  end

  local data = parse_response(raw)
  if not data or not data.files then
    vim.api.nvim_err_writeln("No 'files' field found in the YAML response.")
    return
  end

  if not data.project_name or data.project_name ~= conf.project_name then
    vim.api.nvim_err_writeln("Project name mismatch. The provided changes are for project '" ..
      (data.project_name or "unknown") .. "' but current project is '" ..
      (conf.project_name or "unconfigured") .. "'. Aborting changes.")
    return
  end

  local root = vim.fn.getcwd()

  for _, fileinfo in ipairs(data.files) do
    if not fileinfo.path then
      vim.api.nvim_err_writeln("Invalid file entry. Must have 'path'.")
      goto continue
    end

    -- Ensure the path is within the project root
    if not is_subpath(root, fileinfo.path) then
      vim.api.nvim_err_writeln("Invalid file path outside project root: " .. fileinfo.path)
      goto continue
    end

    if fileinfo.delete == true then
      handler.delete_file(fileinfo.path)
      print("Deleted file: " .. fileinfo.path)
    elseif fileinfo.content then
      handler.write_file(fileinfo.path, fileinfo.content)
      print("Wrote file: " .. fileinfo.path)
    else
      vim.api.nvim_err_writeln("Invalid file entry. Must have 'content' or 'delete' set to true.")
    end
    ::continue::
  end
end

return M