--- Locate, spawn, and wait on a `hephd` daemon. Shared by optional autostart
--- and by the e2e harness (so test readiness uses the same definition the
--- plugin does).

local uv = vim.uv or vim.loop

local M = {}

--- Spawn a `local`-mode hephd against `opts.db` listening on `opts.socket`.
--- `opts.bin` defaults to `hephd` on PATH. Returns `{ handle, pid }`.
function M.spawn(opts)
  local args = { "--mode", "local" }
  if opts.db then
    table.insert(args, "--db")
    table.insert(args, opts.db)
  end
  if opts.socket then
    table.insert(args, "--socket")
    table.insert(args, opts.socket)
  end
  local handle, pid = uv.spawn(opts.bin or "hephd", {
    args = args,
    stdio = { nil, nil, opts.stderr },
  }, function(code, signal)
    if opts.on_exit then
      opts.on_exit(code, signal)
    end
  end)
  if not handle then
    error("heph: failed to spawn hephd (bin=" .. (opts.bin or "hephd") .. ")")
  end
  return { handle = handle, pid = pid }
end

--- Wait until `socket` both exists and accepts a real RPC (`health`). The
--- existence check alone races the daemon's bind→accept, so we prove liveness
--- with a round-trip on a throwaway session. Returns `true`, or `false, reason`.
function M.wait_ready(socket, timeout)
  timeout = timeout or 5000
  if not vim.wait(timeout, function()
    return uv.fs_stat(socket) ~= nil
  end, 20) then
    return false, "socket never appeared: " .. socket
  end
  local session = require("heph.rpc").new_session(socket)
  local ok = vim.wait(timeout, function()
    return pcall(function()
      session:call("health", vim.empty_dict(), { timeout = 200 })
    end)
  end, 50)
  session:close()
  if not ok then
    return false, "socket present but not accepting rpc: " .. socket
  end
  return true
end

return M