local config = require("tiny-debugger.config")

local M = {}

local win_id = nil
local buf_id = nil

local modal_info = {
  { "continue", "Continue" },
  { "step_over", "Step over" },
  { "step_into", "Step into" },
  { "step_out", "Step out" },
  { "run_to_cursor", "Run to cursor" },
  { "watch", "Watch expression" },
  { "hover", "Hover / inspect" },
  { "eval", "Eval in REPL" },
  { "terminate", "Quit debugging" },
  { "restart", "Restart session" },
  { "help", "Show this help" },
}

local global_info = {
  { "toggle", "Toggle debug mode" },
  { "breakpoint", "Toggle breakpoint" },
  { "cond_breakpoint", "Conditional breakpoint" },
  { "clear_breakpoints", "Clear all breakpoints" },
}

local function build_content()
  local lines = { " tiny-debugger", "" }
  local width = #lines[1]

  local function add(key, label)
    local line = string.format("  %-12s %s", key, label)
    lines[#lines + 1] = line
    if #line > width then width = #line end
  end

  lines[#lines + 1] = " Debug mode:"
  for _, pair in ipairs(modal_info) do
    local key = config.opts.keys[pair[1]]
    if key then add(key, pair[2]) end
  end

  lines[#lines + 1] = ""
  lines[#lines + 1] = " Always available:"
  for _, pair in ipairs(global_info) do
    local key = config.opts.global_keys[pair[1]]
    if key then add(key, pair[2]) end
  end

  lines[#lines + 1] = ""
  return lines, width + 2
end

function M.close()
  if win_id and vim.api.nvim_win_is_valid(win_id) then
    vim.api.nvim_win_close(win_id, true)
  end
  win_id = nil
  if buf_id and vim.api.nvim_buf_is_valid(buf_id) then
    vim.api.nvim_buf_delete(buf_id, { force = true })
  end
  buf_id = nil
end

function M.open()
  M.close()

  local lines, width = build_content()

  buf_id = vim.api.nvim_create_buf(false, true)
  vim.api.nvim_buf_set_lines(buf_id, 0, -1, false, lines)
  vim.bo[buf_id].modifiable = false
  vim.bo[buf_id].bufhidden = "wipe"

  win_id = vim.api.nvim_open_win(buf_id, false, {
    relative = "editor",
    anchor = "SE",
    row = vim.o.lines - 2,
    col = vim.o.columns,
    width = width,
    height = #lines,
    style = "minimal",
    border = "rounded",
    focusable = false,
    noautocmd = true,
  })

  vim.api.nvim_create_autocmd({ "CursorMoved", "InsertEnter", "CmdlineEnter" }, {
    once = true,
    callback = function() M.close() end,
  })
end

function M.is_open()
  return win_id ~= nil and vim.api.nvim_win_is_valid(win_id)
end

return M