sync: fix chat reset and payload errors

pages/Plexi-Assistant.py

@@ -286,6 +286,12 @@ def _send_message(endpoint_url, api_key, model, system_prompt, history, user_pro
     if response.status_code == 429:
         detail = response.json().get("error", {}).get("message", "Rate limit exceeded.")
         raise Exception(f"RATE_LIMITED: {detail}")
+    if response.status_code == 413:
+        raise Exception(
+            "PAYLOAD_TOO_LARGE: The study materials are too large for this model's context window. "
+            "Please try asking a more specific question (e.g., 'Tell me viva questions for Unit 1' instead of the whole subject), "
+            "or switch to a model with a larger context window."
+        )
     if response.status_code == 401:
         raise Exception(
             "AUTH_ERROR: Invalid API key. Please check your key and try again."
@@ -384,42 +390,12 @@ def render_onboarding(manifest):
                 "`PLEXI_COOKIE_PASSWORD` is set."
             )
 
-        semester_names = sorted(manifest.keys())
-        default_semester = st.session_state.get("asst_semester")
-        semester_index = (
-            semester_names.index(default_semester)
-            if default_semester in semester_names
-            else 0
-        )
-        selected_semester = st.selectbox(
-            "Semester",
-            semester_names,
-            index=semester_index,
-            key="ob_semester",
-        )
-
-        subject_names = sorted(manifest[selected_semester].keys())
-        default_subject = st.session_state.get("asst_subject")
-        subject_index = (
-            subject_names.index(default_subject)
-            if default_subject in subject_names
-            else 0
-        )
-        selected_subject = st.selectbox(
-            "Subject",
-            subject_names,
-            index=subject_index,
-            key="ob_subject",
-        )
-
         can_start = bool(
             model_name
-            and selected_semester
-            and selected_subject
             and (not needs_key or api_key)
         )
         if st.button(
-            "Start Chatting",
+            "Continue",
             type="primary",
             disabled=not can_start,
             use_container_width=True,
@@ -427,8 +403,6 @@ def render_onboarding(manifest):
             st.session_state.cfg_provider = provider_name
             st.session_state.cfg_base_url = base_url
             st.session_state.cfg_model = model_name
-            st.session_state.asst_semester = selected_semester
-            st.session_state.asst_subject = selected_subject
             st.session_state.remember_device = remember_device
             if api_key:
                 st.session_state.api_key = api_key
@@ -441,8 +415,6 @@ def render_onboarding(manifest):
                         "cfg_base_url": base_url,
                         "cfg_model": model_name,
                         "api_key": api_key,
-                        "asst_semester": selected_semester,
-                        "asst_subject": selected_subject,
                     }
                 )
             else:
@@ -480,6 +452,82 @@ def render_onboarding(manifest):
         )
 
 
+def render_scope_selection(manifest):
+    """Render the subject selection flow before loading materials."""
+    render_page_header(
+        "Plexi assistant",
+        "Select study materials",
+        "Choose a semester and subject to load the corresponding materials for the chat.",
+        badges=[st.session_state.cfg_provider, st.session_state.cfg_model],
+    )
+
+    left_col, right_col = st.columns([1.1, 0.9], gap="large")
+
+    with left_col:
+        st.markdown(
+            """
+            <section class="plexi-panel">
+                <div class="plexi-sidecard-title">Choose your subject</div>
+                <div class="plexi-muted">
+                    Materials for this subject will be loaded into the AI's context.
+                </div>
+            </section>
+            """,
+            unsafe_allow_html=True,
+        )
+
+        semester_names = sorted(manifest.keys())
+        default_semester = st.session_state.get("asst_semester")
+        semester_index = (
+            semester_names.index(default_semester)
+            if default_semester in semester_names
+            else 0
+        )
+        selected_semester = st.selectbox(
+            "Semester",
+            semester_names,
+            index=semester_index,
+            key="asst_semester",
+        )
+
+        subject_names = sorted(manifest[selected_semester].keys())
+        default_subject = st.session_state.get("asst_subject")
+        subject_index = (
+            subject_names.index(default_subject)
+            if default_subject in subject_names
+            else 0
+        )
+        selected_subject = st.selectbox(
+            "Subject",
+            subject_names,
+            index=subject_index,
+            key="asst_subject",
+        )
+
+        if st.button(
+            "Load Materials & Start Chat", type="primary", use_container_width=True
+        ):
+            st.session_state._scope_confirmed = True
+            
+            if st.session_state.get("remember_device"):
+                _save_config(
+                    {
+                        "cfg_provider": st.session_state.cfg_provider,
+                        "cfg_base_url": st.session_state.cfg_base_url,
+                        "cfg_model": st.session_state.cfg_model,
+                        "api_key": st.session_state.get("api_key", ""),
+                        "asst_semester": selected_semester,
+                        "asst_subject": selected_subject,
+                    }
+                )
+            
+            st.session_state.pop("messages", None)
+            st.rerun()
+
+    with right_col:
+        render_external_access()
+
+
 _hydrate_saved_config()
 render_sidebar_intro()
 
@@ -497,6 +545,10 @@ if not _is_configured():
     render_onboarding(manifest)
     st.stop()
 
+if not st.session_state.get("_scope_confirmed"):
+    render_scope_selection(manifest)
+    st.stop()
+
 provider_name = st.session_state.cfg_provider
 base_url = st.session_state.cfg_base_url
 model_name = st.session_state.cfg_model
@@ -522,12 +574,13 @@ if st.session_state.get("_scope_key") != scope_key:
     st.session_state.pop("messages", None)
 
 
-@st.cache_data(show_spinner="Loading study materials...", ttl=300)
+@st.cache_data(show_spinner=False, ttl=300)
 def _get_subject_context(semester, subject):
     return load_subject_context(manifest, semester, subject)
 
 
-subject_text, source_list = _get_subject_context(selected_semester, selected_subject)
+with st.spinner("Loading study materials..."):
+    subject_text, source_list = _get_subject_context(selected_semester, selected_subject)
 if not subject_text.strip():
     st.warning("No readable text was found for this subject. Try another selection.")
     st.stop()
@@ -824,15 +877,30 @@ if prompt:
                     if st.button("Retry", type="primary"):
                         st.rerun()
                     st.stop()
+                if "PAYLOAD_TOO_LARGE" in err_text:
+                    err_msg = err_text.split(": ", 1)[1]
+                    st.session_state.messages.append({
+                        "role": "assistant",
+                        "content": f"**System Error:** {err_msg}"
+                    })
+                    st.rerun()
                 if "AUTH_ERROR" in err_text:
-                    st.error(err_text.split(": ", 1)[1])
+                    err_msg = err_text.split(": ", 1)[1]
                     _clear_saved_config()
                     st.session_state.remember_device = False
                     if "api_key" in st.session_state:
                         del st.session_state.api_key
-                    st.session_state.messages.pop()
-                    st.stop()
-                raise
+                    st.session_state.messages.append({
+                        "role": "assistant",
+                        "content": f"**System Error:** {err_msg}"
+                    })
+                    st.rerun()
+                
+                st.session_state.messages.append({
+                    "role": "assistant",
+                    "content": f"**System Error:** {err_text}"
+                })
+                st.rerun()
 
             st.markdown(answer)
 

utils.py

@@ -503,6 +503,22 @@ $palette_vars
             background: var(--plexi-expander-background);
         }
 
+        div[data-testid="stToast"] {
+            background: var(--plexi-panel-strong) !important;
+            color: var(--plexi-ink) !important;
+            border: 1px solid var(--plexi-line) !important;
+            box-shadow: var(--plexi-shadow) !important;
+        }
+
+        div[data-testid="toastContainer"] * {
+            color: var(--plexi-ink) !important;
+        }
+
+        div[data-testid="stSpinner"] > div,
+        div[data-testid="stSpinner"] * {
+            color: var(--plexi-ink) !important;
+        }
+
         div[data-baseweb="popover"],
         div[data-baseweb="popover"] > div,
         div[data-baseweb="popover"] > div > div,