"""End-to-end viewer regression: requires Playwright and a browser.

Build the chapter, then run python graph/test_browser.py chapter25 --browser msedge.
Use --browser firefox for Playwright's Firefox build. See README.md for setup.
"""
from pathlib import Path
import argparse
from functools import partial
from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
import os
import subprocess
import sys
import time
from threading import Thread

ROOT = Path(__file__).resolve().parent.parent
# Optional workspace-local test dependencies; no runtime dependency for the viewer.
sys.path.insert(0, str(ROOT / "build/graph-tools"))
if (ROOT / "build/graph-browsers").is_dir():
    os.environ.setdefault("PLAYWRIGHT_BROWSERS_PATH", str(ROOT / "build/graph-browsers"))
from playwright.sync_api import sync_playwright


def check(chapter, browser_name):
    number = int(chapter.removeprefix("chapter"))
    package = "com.seaofnodes.simple." + ("print." if number >= 20 else "")
    artifacts = ROOT / "build/graph-browser" / (chapter + "-" + browser_name)
    artifacts.mkdir(parents=True, exist_ok=True)
    log = artifacts / "compiler.log"
    with log.open("w") as output:
        process = subprocess.Popen([
            "java", "-ea", "-Dsimple.graph.open=false", "-cp", "build/classes/main",
            package + "JSViewer"], cwd=ROOT/chapter, stdout=output, stderr=subprocess.STDOUT)
        try:
            for _ in range(200):
                text = log.read_text()
                if "Graph viewer: " in text:
                    break
                assert process.poll() is None, text
                time.sleep(.05)
            url = text.split("Graph viewer: ")[1].splitlines()[0]
            with sync_playwright() as playwright:
                browser = (playwright.firefox.launch(headless=True) if browser_name == "firefox"
                           else playwright.chromium.launch(channel=browser_name, headless=True))
                page = browser.new_page(viewport={"width": 1400, "height": 1000})
                errors = []
                page.on("pageerror", lambda error: errors.append(str(error)))
                page.goto(url)
                page.wait_for_function("done && current === 0 && !rendering", timeout=15000)
                assert page.locator("#graph svg g.node").count() > 0
                assert page.locator("#doPrev").is_disabled()
                page.locator("#doNext").click()
                page.wait_for_function("current === 1 && !rendering")
                page.locator("#doPrev").click()
                page.wait_for_function("current === 0 && !rendering")
                # Keep the real renderer, but shorten animation for the remaining steps.
                page.evaluate('renderer.transition(() => d3.transition("test").duration(0))')
                for source in ("return 1 + 2;",
                               "int x=0; while(x<arg) { x=x+1; } return x;"):
                    previous = page.evaluate("generation")
                    page.locator("#program").fill(source)
                    page.locator("#compile").click()
                    page.wait_for_function(
                        "previous => generation > previous && done && current === 0 && !rendering",
                        arg=previous, timeout=15000)
                    total = int(page.locator("#len").inner_text())
                    assert total > 1
                    for index in range(1, total):
                        page.locator("#doNext").click()
                        page.wait_for_function("index => current === index && !rendering", arg=index)
                    assert page.locator("#doNext").is_disabled()
                    assert "error" not in page.locator("#status").inner_text().lower()
                    if number == 25:
                        # An undeclared DOT endpoint appears as a bare numeric-ID node.
                        assert not page.locator("#graph g.node").evaluate_all("""
                            nodes => nodes.filter(node => {
                              const id = node.querySelector('title').textContent;
                              const texts = [...node.querySelectorAll('text')];
                              return /^n[0-9]+$/.test(id) && texts.length === 1 &&
                                     texts[0].textContent === id;
                            }).length
                        """), "Graph contains an undeclared endpoint"
                    print(chapter, browser_name, total, "frames rendered:", source, flush=True)
                assert not errors, errors
                page.screenshot(path=str(artifacts / "viewer.png"))
                page.locator("#doExit").click()
                page.wait_for_function("document.getElementById('status').textContent.includes('disconnected')")
                assert not page.is_closed()
                assert process.wait(timeout=5) == 0, log.read_text()[-2000:]
                # A page opened without any compiler must not remain "Connecting...".
                class QuietHandler(SimpleHTTPRequestHandler):
                    def log_message(self, *args):
                        pass
                http = ThreadingHTTPServer(("127.0.0.1", 0),
                    partial(QuietHandler, directory=str(ROOT / "graph/web")))
                thread = Thread(target=http.serve_forever, daemon=True)
                thread.start()
                try:
                    offline = browser.new_page()
                    offline.goto("http://127.0.0.1:" + str(http.server_port) + "/index.html")
                    offline.wait_for_function(
                        "document.getElementById('status').textContent.includes('disconnected')")
                    assert offline.locator("#compile").is_disabled()
                    assert not offline.is_closed()
                finally:
                    http.shutdown()
                    http.server_close()
                    thread.join()
                browser.close()
        finally:
            if process.poll() is None:
                process.terminate()
                process.wait(timeout=5)
    print(chapter, browser_name, "startup, forward/back, recompile, all frames, disconnect, and offline startup passed")


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("chapter", nargs="?", default="chapter25")
    parser.add_argument("--browser", default="msedge", choices=("msedge", "chrome", "firefox"))
    args = parser.parse_args()
    check(args.chapter, args.browser)