--- E2e harness (tech-spec §9): spin up a real `hephd` in local mode against a
--- temp DB + socket, point the plugin at it, and tear it down deterministically.
--- Step builders (create doc/task, open, edit, save) are reusable across specs.

local rpc = require("heph.rpc")
local uv = vim.uv or vim.loop

local M = {}
local counter = 0

--- Spawn a `local`-mode hephd against `db` listening on `socket` (test infra —
--- the plugin itself is connect-only; the daemon is normally an OS service).
local function spawn(opts)
  local args = { "--mode", "local", "--db", opts.db, "--socket", opts.socket }
  local handle, pid = uv.spawn(opts.bin, {
    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-test: failed to spawn hephd (bin=" .. tostring(opts.bin) .. ")")
  end
  return { handle = handle, pid = pid }
end

--- Wait until `socket` exists and answers `health`. Plain Lua loop — never a
--- `vim.wait` predicate (the rpc round-trip uses `vim.wait`; nesting deadlocks).
local function wait_ready(socket, timeout)
  timeout = timeout or 5000
  local deadline = uv.hrtime() + timeout * 1e6
  while uv.hrtime() < deadline do
    if uv.fs_stat(socket) ~= nil then
      local session = rpc.new_session(socket)
      local ok = pcall(function()
        session:call("health", vim.empty_dict(), { timeout = 200 })
      end)
      session:close()
      if ok then
        return true
      end
    end
    vim.wait(50)
  end
  return false, "daemon not ready at " .. socket
end

M.wait_ready = wait_ready

local function repo_root()
  -- ":p" makes this absolute regardless of how the runner was launched.
  local here = vim.fn.fnamemodify(debug.getinfo(1, "S").source:sub(2), ":p")
  return vim.fn.fnamemodify(here, ":h:h:h:h") -- .../heph.nvim/tests/e2e -> repo root
end

--- The hephd binary to drive: `$HEPHD_BIN` or the workspace debug build.
function M.hephd_bin()
  local env = vim.env.HEPHD_BIN
  if env and #env > 0 then
    return env
  end
  return repo_root() .. "/target/debug/hephd"
end

-- A short unique temp dir. unix socket paths are capped near 104 bytes
-- (`sun_path`), so we stay under a short base, never `tempname()`.
local function unique_dir()
  counter = counter + 1
  local base = vim.env.HEPH_TEST_TMP
  base = (base and #base > 0) and base:gsub("/+$", "") or "/tmp"
  local dir = string.format("%s/h%d-%d", base, vim.fn.getpid(), counter)
  vim.fn.mkdir(dir, "p")
  return dir
end

--- A fresh temp dir + short socket/db paths, WITHOUT spawning a daemon (for
--- tests of the no-daemon-running case). `rm` removes it.
function M.tmp()
  local dir = unique_dir()
  return { dir = dir, sock = dir .. "/s", db = dir .. "/db", rm = function()
    pcall(function()
      vim.fn.delete(dir, "rf")
    end)
  end }
end

--- Start a daemon on explicit paths and bind the plugin's rpc to it. Returns a
--- `ctx` with `dir, sock, db, daemon, exited, q` (an isolated assert session).
function M.start_on(dir, sock, db)
  assert(#sock < 104, "socket path too long for sun_path: " .. sock)
  local bin = M.hephd_bin()
  assert(
    vim.fn.executable(bin) == 1,
    "hephd not built/executable: " .. bin .. "  (run: cargo build -p hephd)"
  )

  local exited = { done = false }
  local d = spawn({
    bin = bin,
    db = db,
    socket = sock,
    on_exit = function()
      exited.done = true
    end,
  })
  local ok, reason = wait_ready(sock, 5000)
  assert(ok, "daemon not ready: " .. tostring(reason))

  rpc.setup(sock) -- the plugin's default session, used by buffers/commands
  return {
    dir = dir,
    sock = sock,
    db = db,
    daemon = d,
    exited = exited,
    q = rpc.new_session(sock), -- isolated session for independent assertions
  }
end

--- Start a fresh daemon on a new temp dir and bind the plugin's rpc to it.
function M.start()
  local dir = unique_dir()
  return M.start_on(dir, dir .. "/s", dir .. "/db")
end

--- Tear down: close sessions, delete heph:// buffers, reap the daemon, rm temp.
function M.stop(ctx)
  if not ctx then
    return
  end
  pcall(function()
    ctx.q:close()
  end)
  pcall(function()
    rpc.close()
  end)
  for _, b in ipairs(vim.api.nvim_list_bufs()) do
    if vim.api.nvim_buf_get_name(b):match("^heph://") then
      pcall(vim.api.nvim_buf_delete, b, { force = true })
    end
  end
  local h = ctx.daemon and ctx.daemon.handle
  if h then
    if not ctx.exited.done then
      pcall(function()
        h:kill("sigterm")
      end)
      vim.wait(2000, function()
        return ctx.exited.done
      end, 20)
    end
    pcall(function()
      if not h:is_closing() then
        h:close()
      end
    end)
  end
  pcall(function()
    vim.fn.delete(ctx.dir, "rf")
  end)
end

-- --- step builders (drive the plugin's default session) ---

function M.create_doc(title, body)
  return rpc.call("node.create", { kind = "doc", title = title, body = body or "" })
end

function M.create_task(opts)
  return rpc.call("task.create", opts or {})
end

--- Open node `id` in a buffer; returns the buffer handle.
function M.open(id)
  require("heph.node").open(id)
  return vim.api.nvim_get_current_buf()
end

function M.set_lines(buf, lines)
  vim.api.nvim_buf_set_lines(buf, 0, -1, false, lines)
end

--- Save a heph:// buffer (fires BufWriteCmd → node.update).
function M.save(buf)
  vim.api.nvim_buf_call(buf, function()
    vim.cmd("write")
  end)
end

return M