-- Real libpanto-lua callback integration check for panto-warming.
-- Run under the callback-capable host with: panto lua binding-check.lua
-- Local TCP fixtures exercise refusal, a scripted SSE response, and a held
-- request; synchronization uses loop events, never sleeps.
local here = (arg and arg[0] or "binding-check.lua"):match("^(.*)/") or "."
package.path = here .. "/?.lua;" .. here .. "/?/init.lua;" .. package.path

local panto = require("panto")
local uv = require("luv")
local warm = require("warming.warm")
local declarations = {
    { name = "warming_probe", description = "integration fixture", parameters = {
        type = "object", properties = {},
    } },
}
local resources, failure = {}, nil
local attached = false
local shutdown_done = false

local function track(handle)
    resources[#resources + 1] = handle
    return handle
end

local function guarded(fn)
    return function(...)
        local ok, err = pcall(fn, ...)
        if not ok then failure = tostring(err) end
    end
end

local function run_until(done, what)
    while not done() do
        assert(not failure, failure)
        local alive = uv.run("once")
        assert(not failure, failure)
        assert(alive or done(), what .. ": loop became idle before completion")
    end
    assert(not failure, failure)
end

local function close(handle)
    if handle and not handle:is_closing() then handle:close() end
end

local function close_and_wait(handle)
    local done = false
    handle:close(function() done = true end)
    run_until(function() return done end, "waiting for local TCP close")
end

local function close_resources()
    for _, handle in ipairs(resources) do close(handle) end
end

local function configure(port)
    panto.ext = {
        session_info = function()
            return { session_dir = "/tmp/panto-warming-check", session_id = "check", model = "fixture" }
        end,
        resolve_model = function()
            return {
                api_style = "openai_chat", api_key = "local-only",
                base_url = "http://127.0.0.1:" .. port, model = "fixture",
            }
        end,
        agent = { tools = function() return declarations end },
    }
end

local function timer_start(port, prompt)
    configure(port)
    local handle, start_error
    local timer = track(uv.new_timer())
    timer:start(0, 0, guarded(function()
        close(timer)
        handle, start_error = warm.start(prompt)
        if handle then
            assert(warm.poll(handle) == nil, "run_async delivered inline from timer startup")
        end
    end))
    run_until(function() return handle ~= nil or start_error ~= nil end, "starting warm turn")
    assert(handle, "warm.start failed: " .. tostring(start_error))
    return handle
end

local function wait_terminal(handle, what)
    run_until(function() return warm.poll(handle) ~= nil end, what)
    return warm.poll(handle)
end

local function closed_unused_port()
    local socket = track(uv.new_tcp())
    assert(socket:bind("127.0.0.1", 0))
    local port = socket:getsockname().port
    close_and_wait(socket)
    return port
end

local function listener(on_client)
    local server = track(uv.new_tcp())
    assert(server:bind("127.0.0.1", 0))
    server:listen(8, guarded(function(err)
        assert(not err, tostring(err))
        local client = track(uv.new_tcp())
        server:accept(client)
        on_client(client)
    end))
    return server, server:getsockname().port
end

local function serve_sse()
    local request, client
    local body = table.concat({
        'data: {"id":"warm","object":"chat.completion.chunk","created":1,"model":"fixture","choices":[{"index":0,"delta":{"role":"assistant","content":"OK"},"finish_reason":null}]}\n\n',
        'data: {"id":"warm","object":"chat.completion.chunk","created":1,"model":"fixture","choices":[{"index":0,"delta":{},"finish_reason":"stop"}]}\n\n',
        "data: [DONE]\n\n",
    })
    local response = "HTTP/1.1 200 OK\r\nContent-Type: text/event-stream\r\nContent-Length: "
        .. #body .. "\r\nConnection: close\r\n\r\n" .. body
    local server, port = listener(function(accepted)
        client = accepted
        local received = ""
        accepted:read_start(guarded(function(err, data)
            assert(not err, tostring(err))
            if not data then return end
            received = received .. data
            local boundary = received:find("\r\n\r\n", 1, true)
            if not boundary then return end
            local header = received:sub(1, boundary - 1):lower()
            local length = tonumber(header:match("\r\ncontent%-length:%s*(%d+)"))
            assert(length, "request omitted Content-Length")
            local first_body = boundary + 4
            if #received < first_body - 1 + length then return end
            request = received:sub(first_body, first_body + length - 1)
            accepted:read_stop()
            accepted:write(response, guarded(function(write_err)
                assert(not write_err, tostring(write_err))
                accepted:shutdown(guarded(function(shutdown_err)
                    assert(not shutdown_err, tostring(shutdown_err))
                    close(accepted)
                end))
            end))
        end))
    end)
    return server, port, function() return request end, function() return client end
end

local function serve_and_hold()
    local accepted, client
    local server, port = listener(function(socket)
        client = socket
        accepted = true
        socket:read_start(guarded(function(err)
            assert(not err, tostring(err))
        end))
    end)
    return server, port, function() return accepted end
end

local function main()
    assert(panto.async and type(panto.async.attach_luv) == "function",
        "callback-capable panto.async API is required")
    assert(panto.async.attach_luv())
    attached = true
    panto.file_system_jsonl_store = function()
        return { load = function() return panto.conversation() end }
    end

    -- A closed ephemeral listener gives a deterministic local refusal.
    local refused = timer_start(closed_unused_port(), "refused-probe")
    local refused_result = wait_terminal(refused, "waiting for refused request")
    assert(refused_result.status == "failed" and type(refused_result.err) == "string",
        "connection refusal must arrive as failed termination with a diagnostic")

    -- A real OpenAI-compatible SSE response completes a callback turn. Verify
    -- that copied declarations and the transient prompt reach the provider.
    local sse_server, sse_port, get_request, get_sse_client = serve_sse()
    local completed = timer_start(sse_port, "sse-probe")
    local complete_result = wait_terminal(completed, "waiting for scripted SSE")
    assert(complete_result.status == "completed", "scripted SSE must complete the warm turn")
    local request = assert(get_request(), "SSE fixture did not receive the HTTP request")
    assert(request:find('"stream":true', 1, true), "warm request must stream")
    assert(request:find('"tools"', 1, true) and request:find('"warming_probe"', 1, true),
        "session tool declarations must be copied to the warm request")
    assert(request:find("sse-probe", 1, true), "transient prompt must reach the provider")
    close(get_sse_client())
    close(sse_server)

    -- Keep a request pending, then close its subscription. Native shutdown
    -- joins it without delivering a late result to the extension.
    local hold_server, hold_port, was_accepted = serve_and_hold()
    local abandoned = timer_start(hold_port, "abandon-probe")
    run_until(function() return was_accepted() or warm.poll(abandoned) ~= nil end,
        "waiting for held request acceptance")
    assert(was_accepted() and warm.poll(abandoned) == nil, "held request should still be live")
    warm.abandon(abandoned)
    assert(abandoned.abandoned and abandoned.result == nil, "abandon clears cached state")

    assert(panto.async.shutdown("wait"), "standalone binding shutdown must finish")
    shutdown_done = true
    assert(warm.poll(abandoned) == nil and abandoned.result == nil,
        "closed subscription must suppress terminal delivery")
    close(hold_server)
end

local ok, err = xpcall(main, debug.traceback)
if not ok then
    if attached and not shutdown_done then pcall(panto.async.shutdown, "wait") end
    close_resources()
    pcall(uv.run, "nowait")
    io.stderr:write("panto-warming real-binding check failed: " .. tostring(err) .. "\n")
    error(err, 0)
end

-- Close all local fixtures after orderly binding shutdown, then let luv
-- deliver their close callbacks before this standalone state exits.
close_resources()
uv.run()
io.stderr:write("panto-warming real-binding check: OK\n")