"""Generate backnforth manual illustrations via Gemini image API (nano banana)."""
import base64
import json
import os
import sys
import time
import urllib.request

# key from disk, never printed
KEY = os.environ.get("GEMINI_API_KEY")
if not KEY:
    sys.exit('set GEMINI_API_KEY in the environment first')

MODELS = ['gemini-3-pro-image', 'gemini-3.1-flash-image',
          'gemini-2.5-flash-image']

STYLE = ("Flat vector cartoon illustration in a warm, friendly picture-book style. "
         "Soft rounded shapes, thick clean outlines, muted palette of deep teal, warm coral, "
         "cream and soft mustard yellow. Cozy, calm, reassuring mood. Simple, uncluttered "
         "composition on a plain cream background. Absolutely no text, no letters, no numbers, "
         "no words anywhere in the image. Landscape orientation. ")

SCENES = {
    '01-cover': "A friendly therapist and a relaxed patient sitting in comfy armchairs in a cozy "
                "counselling room with a potted plant and a soft floor lamp. On a low table between "
                "them, an open laptop shows a dark screen with a single glowing green dot.",
    '02-open': "Close-up of gentle hands opening a slightly-worn laptop on a wooden table. The screen "
               "shows a simple dark page with one large round green play button and a small green dot.",
    '03-link': "One hand passing an old smartphone to another person's open hand. The phone screen "
               "glows dark with a single bright green dot. In the soft-focus background, a laptop "
               "shows the same green dot, suggesting the two screens are connected by a dotted arc.",
    '04-follow': "Side profile of a calm person's face with a serene expression, eyes looking to one "
                 "side, following a small glowing green dot that trails a gentle curved motion path "
                 "from the left side of the image to the right.",
    '05-adjust': "A hand with one finger adjusting a single very large horizontal slider on a dark "
                 "tablet screen. At the left end of the slider sits a tiny cute cartoon turtle, at "
                 "the right end a tiny cute cartoon rabbit.",
    '06-care': "A therapist leaning forward attentively with a kind expression, offering a glass of "
               "water to a patient who looks calm and relieved. The laptop on the side table is "
               "closed. Warm afternoon light through a window.",
}

OUT = os.path.expanduser('~/Documents/backnforth/img/manual')
os.makedirs(OUT, exist_ok=True)


def generate(prompt):
    body = json.dumps({'contents': [{'parts': [{'text': prompt}]}]}).encode()
    last = None
    for model in MODELS:
        url = ('https://generativelanguage.googleapis.com/v1beta/models/'
               '%s:generateContent?key=%s' % (model, KEY))
        req = urllib.request.Request(url, data=body,
                                     headers={'Content-Type': 'application/json'})
        for attempt in (1, 2):
            try:
                with urllib.request.urlopen(req, timeout=300) as r:
                    data = json.load(r)
                for part in data['candidates'][0]['content']['parts']:
                    if 'inlineData' in part:
                        return base64.b64decode(part['inlineData']['data']), model
                last = 'no image part in response from %s' % model
                break  # empty response: don't retry same model, fall through
            except Exception as e:
                last = '%s (try %d): %s' % (model, attempt, e)
    raise RuntimeError(last)


for name, scene in SCENES.items():
    path = os.path.join(OUT, name + '.png')
    if os.path.exists(path):
        print(name, 'exists, skipping')
        continue
    img, model = generate(STYLE + scene)
    open(path, 'wb').write(img)
    print('%s: %d KB via %s' % (name, len(img) // 1024, model))
    time.sleep(2)
print('done')