import time, sys, requests
from html.parser import HTMLParser

class FormFieldParser(HTMLParser):
    def __init__(self):
        super().__init__()
        self.hidden_fields = {}
        self.visible_fields = {}
        self._in_select = None
        self._in_textarea = None
        self._textarea_value = ""
        self._select_options = []
    def handle_starttag(self, tag, attrs):
        ad = dict(attrs)
        tl = tag.lower()
        if tl == "input":
            name = ad.get("name")
            if not name: return
            it = ad.get("type", "text").lower()
            val = ad.get("value", "")
            if it == "hidden": self.hidden_fields[name] = val
            elif it in ("submit","button","image","file"): pass
            elif it == "checkbox": self.visible_fields[name] = {"type":"checkbox","value":val or "on"}
            elif it == "radio":
                if name not in self.visible_fields: self.visible_fields[name] = {"type":"radio","value":val or "1"}
            elif it == "number": self.visible_fields[name] = {"type":"number","value":val}
            else: self.visible_fields[name] = {"type":it,"value":val}
        elif tl == "select":
            name = ad.get("name")
            if name: self._in_select = name; self._select_options = []
        elif tl == "option" and self._in_select:
            val = ad.get("value", "")
            if val: self._select_options.append(val)
        elif tl == "textarea":
            name = ad.get("name")
            if name: self._in_textarea = name; self._textarea_value = ""
    def handle_data(self, data):
        if self._in_textarea is not None: self._textarea_value += data
    def handle_endtag(self, tag):
        tl = tag.lower()
        if tl == "select" and self._in_select:
            name = self._in_select
            if self._select_options: self.visible_fields[name] = {"type":"select","value":self._select_options[0]}
            else: self.visible_fields[name] = {"type":"select","value":"1"}
            self._in_select = None; self._select_options = []
        elif tl == "textarea" and self._in_textarea is not None:
            name = self._in_textarea
            self.visible_fields[name] = {"type":"textarea","value":self._textarea_value.strip()}
            self._in_textarea = None

def parse_form_fields(html_text):
    parser = FormFieldParser()
    parser.feed(html_text)
    return parser.hidden_fields, parser.visible_fields

def build_post_data(hf, vf):
    data = dict(hf)
    for name, info in vf.items():
        ft = info["type"]; ev = info["value"]
        if ev: data[name] = ev
        elif ft in ("number","radio"): data[name] = "1"
        elif ft == "textarea": data[name] = "test"
        elif ft == "checkbox": data[name] = info["value"]
        elif ft == "select": data[name] = info["value"]
        else: data[name] = "test"
    return data

KEY_PAGES = ("Cases","ReviewStatements","Feedback","Redirect","Consent","Instructions","Demographics")
MAX_PAGES = 150
DELAY = 0.2
MAX_RETRIES = 3
START_URL = "http://localhost:8000/p/gcya43h4/welfare_study/Consent/3"

def page_label(url):
    parts = url.rstrip("/").split("/")
    try:
        idx = parts.index("welfare_study")
        return "/".join(parts[idx+1:])
    except ValueError: return url.split("/")[-1] or url

def is_key_page(url):
    for kw in KEY_PAGES:
        if kw in url: return True
    return False

def advance_participant():
    session = requests.Session()
    current_url = START_URL
    page_count = 0
    stuck_count = 0
    print(f"Starting at: {current_url}")
    print(f"Max pages: {MAX_PAGES}, delay: {DELAY}s")
    print("-" * 60)
    while page_count < MAX_PAGES:
        for attempt in range(1, MAX_RETRIES + 1):
            try:
                resp = session.get(current_url, timeout=15)
                if resp.status_code == 500:
                    print(f"  WARNING: 500 error on {current_url}")
                    print(f"  Response snippet: {resp.text[:200]}")
                    # Still try to proceed
                break
            except (requests.ConnectionError, requests.Timeout) as e:
                print(f"  [retry {attempt}/{MAX_RETRIES}] GET failed: {e}")
                if attempt == MAX_RETRIES:
                    print("FAILURE: could not connect after retries.")
                    return False, page_count
                time.sleep(1)
        html = resp.text
        landed_url = resp.url
        if "Redirect" in landed_url:
            label = page_label(landed_url)
            print(f"  Page {page_count}: -> {label}  *** REACHED REDIRECT ***")
            print("-" * 60)
            print(f"Total pages traversed: {page_count}")
            print("SUCCESS")
            return True, page_count
        hidden, visible = parse_form_fields(html)
        label = page_label(landed_url)
        if page_count % 20 == 0 or is_key_page(landed_url):
            vis_names = list(visible.keys())[:5]
            print(f"  Page {page_count}: {label}  (hidden={len(hidden)}, visible={len(visible)}: {vis_names})")
        post_data = build_post_data(hidden, visible)
        for attempt in range(1, MAX_RETRIES + 1):
            try:
                post_resp = session.post(landed_url, data=post_data, timeout=15, allow_redirects=True)
                break
            except (requests.ConnectionError, requests.Timeout) as e:
                print(f"  [retry {attempt}/{MAX_RETRIES}] POST failed: {e}")
                if attempt == MAX_RETRIES:
                    print("FAILURE: could not connect after retries.")
                    return False, page_count
                time.sleep(1)
        new_url = post_resp.url
        if new_url == landed_url:
            stuck_count += 1
            if stuck_count == 1:
                post_data_minimal = dict(hidden)
                try:
                    post_resp = session.post(landed_url, data=post_data_minimal, timeout=15, allow_redirects=True)
                    new_url = post_resp.url
                except (requests.ConnectionError, requests.Timeout): pass
            if new_url == landed_url and stuck_count >= 3:
                print(f"  STUCK on {label} after {stuck_count} attempts. Trying empty POST...")
                csrf = hidden.get("csrfmiddlewaretoken", "")
                if csrf:
                    try:
                        post_resp = session.post(landed_url, data={"csrfmiddlewaretoken": csrf}, timeout=15, allow_redirects=True)
                        new_url = post_resp.url
                    except (requests.ConnectionError, requests.Timeout): pass
            if new_url == landed_url and stuck_count >= 5:
                print(f"  FAILURE: stuck on {label} for {stuck_count} consecutive attempts.")
                print(f"Total pages traversed: {page_count}")
                print("FAILURE")
                return False, page_count
        else:
            stuck_count = 0
        current_url = new_url
        page_count += 1
        time.sleep(DELAY)
    print(f"Total pages traversed: {page_count}")
    print("FAILURE: reached max page limit.")
    return False, page_count

if __name__ == "__main__":
    success, count = advance_participant()
    sys.exit(0 if success else 1)