-- ReaAssist Installer
-- https://reaassist.app
--
-- Downloads the small ReaAssist bootstrap script, registers it as a
-- REAPER action, then launches it. ReaAssist fetches the rest on first run.
--
-- To run: REAPER > Actions > Show action list > Load ReaScript,
-- choose this file, then click Run.

local INSTALL_REL = "Scripts/mbriggs-reaper/ReaAssist/"
local SCRIPT_URL  = "https://raw.githubusercontent.com/michaelbriggsaudio/mbriggs-reaper/main/ReaAssist/ReaAssist.lua"

local function die(msg)
  reaper.MB(msg, "ReaAssist Installer", 0)
end

local function read_file(path)
  local f = io.open(path, "rb")
  if not f then return nil end
  local content = f:read("*a")
  f:close()
  return content
end

-- Install into the normal ReaAssist script folder.
local target_dir  = reaper.GetResourcePath() .. "/" .. INSTALL_REL
local final_path  = target_dir .. "ReaAssist.lua"
local tmp_path    = final_path .. ".tmp"
reaper.RecursiveCreateDirectory(target_dir, 0)

-- Download to .tmp with curl. On macOS, use the system path because
-- REAPER-launched scripts may not inherit PATH reliably.
local os_name  = reaper.GetOS() or ""
local is_mac   = os_name:match("OSX") or os_name:match("macOS")
local curl_bin = is_mac and "/usr/bin/curl" or "curl"

local cmd = string.format(
  '%s -fsSL --connect-timeout 10 --max-time 45 -o "%s" "%s"',
  curl_bin, tmp_path, SCRIPT_URL)
local rc = reaper.ExecProcess(cmd, 60000)

if not rc then
  -- Curl never launched, so there is no exit code to report.
  os.remove(tmp_path)
  die("Could not launch curl from REAPER (ExecProcess returned nil).\n\n" ..
      "Command attempted:\n" .. cmd .. "\n\n" ..
      "You can install ReaAssist manually from " ..
      "https://github.com/michaelbriggsaudio/mbriggs-reaper")
  return
end

if not rc:match("^0\n") then
  os.remove(tmp_path)
  local code   = rc:match("^(%d+)") or "?"
  local detail = rc:sub(1, 300)
  die(string.format(
    "Download failed (curl exit %s).\n\n" ..
    "%s\n\n" ..
    "Check your network connection and try again.\n\n" ..
    "If the problem continues, you can install ReaAssist manually " ..
    "from https://github.com/michaelbriggsaudio/mbriggs-reaper",
    code, detail))
  return
end

-- Make sure the download is really ReaAssist.lua.
local content = read_file(tmp_path)
local has_header  = content and content:match("ReaAssist %- REAPER Smart Assistant")
local has_version = content and content:match('VERSION%s*=%s*"%d+%.%d+%.%d+"')
if not (has_header and has_version) then
  os.remove(tmp_path)
  die("Downloaded file does not look like ReaAssist. Try again later.")
  return
end

-- Replace safely: back up the old script, move the new one in, then
-- restore the backup if the final move fails.
local backup_path = final_path .. ".bak"
local existing = io.open(final_path, "rb")
local has_existing = existing ~= nil
if existing then existing:close() end

if has_existing then
  os.remove(backup_path)  -- remove any stale backup from a prior attempt
  local ok, err = os.rename(final_path, backup_path)
  if not ok then
    os.remove(tmp_path)
    die("Could not back up existing ReaAssist.lua: " .. tostring(err))
    return
  end
end

local ok, err = os.rename(tmp_path, final_path)
if not ok then
  -- Roll back if we already moved the old script aside.
  if has_existing then os.rename(backup_path, final_path) end
  os.remove(tmp_path)
  die("Could not move downloaded file into place: " .. tostring(err))
  return
end

-- New script is in place; clean up the backup.
if has_existing then os.remove(backup_path) end

-- Register it as a permanent REAPER action.
local action_id = reaper.AddRemoveReaScript(true, 0, final_path, true)
if action_id == 0 then
  die("ReaAssist was downloaded successfully but could not be " ..
      "registered as a REAPER action. You can load it manually from:\n\n" ..
      final_path)
  return
end

-- Launch ReaAssist; its bootstrap fetches the remaining files.
reaper.Main_OnCommand(action_id, 0)