"""
Character Forge - Main Application Entry Point
===============================================

License: GNU AGPL v3.0
Copyright (C) 2025 Gregor Hubert, Max Koch "cronos3k"

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Main entry point for the Character Forge Streamlit application.
Run with: streamlit run app.py
"""

import streamlit as st
from pathlib import Path

# Import configuration
from config.settings import Settings

# Import components
from ui.components.backend_selector import render_backend_selector
from ui.components.status_display import render_status_display


def initialize_session_state():
    """
    Initialize Streamlit session state with default values.

    Session state is Streamlit's way of persisting data across reruns.
    This function sets up all the global state our app needs.
    """
    # Backend selection
    if 'backend' not in st.session_state:
        st.session_state.backend = "Gemini API (Cloud)"

    # API keys
    if 'gemini_api_key' not in st.session_state:
        st.session_state.gemini_api_key = Settings.get_gemini_api_key()

    # Output directory
    if 'output_dir' not in st.session_state:
        st.session_state.output_dir = Settings.OUTPUT_DIR

    # Generation history
    if 'history' not in st.session_state:
        st.session_state.history = []


def render_header():
    """Render the application header and global controls."""
    st.set_page_config(
        page_title="Character Forge - AI Image Generation",
        page_icon="🔥",
        layout="wide",
        initial_sidebar_state="expanded"
    )

    st.title("🔥 Character Forge - AI Image Generation")
    st.markdown(
        """
        **Professional character sheets and multi-image composition powered by AI**

        *Supports Gemini API, OmniGen2, and ComfyUI backends*
        """
    )

    # Show API key warning if not configured
    if not st.session_state.get('gemini_api_key'):
        st.warning(
            "⚠️ **API Key Required**: Please enter your Gemini API key in the sidebar to start generating. "
            "Get a free API key at [Google AI Studio](https://aistudio.google.com/app/apikey).",
            icon="🔑"
        )

    st.divider()


def render_global_backend_selector():
    """
    Render the global backend selector that applies to all pages.

    This is one of the key improvements over Gradio - no parameter drilling!
    The backend selection is stored in session_state and accessible everywhere.
    """
    st.subheader("🔧 Generation Backend")

    col1, col2 = st.columns([2, 1])

    with col1:
        # Render the backend selector component
        backend = render_backend_selector()
        st.session_state.backend = backend

    with col2:
        # Render status display
        if st.button("🔄 Refresh Status"):
            st.rerun()

    st.divider()


def render_sidebar():
    """Render the sidebar with navigation and settings."""
    with st.sidebar:
        st.image("https://via.placeholder.com/150x150.png?text=🍌", width=150)

        st.markdown("## Navigation")
        st.page_link("pages/01_🔥_Character_Forge.py", label="🔥 Character Forge")
        st.page_link("pages/02_🎬_Composition_Assistant.py", label="🎬 Composition Assistant")
        st.page_link("pages/03_📸_Standard_Interface.py", label="📸 Standard Interface")

        st.divider()

        st.markdown("## Settings")

        # API Key input (for Gemini)
        st.markdown("### 🔑 API Key")
        st.info("Get your FREE API key at [Google AI Studio](https://aistudio.google.com/app/apikey)")

        api_key = st.text_input(
            "Gemini API Key",
            value=st.session_state.gemini_api_key or "",
            type="password",
            help="Enter your Google Gemini API key. Required for Gemini backend. Your key stays in YOUR session only.",
            placeholder="Enter your API key here..."
        )
        if api_key != st.session_state.gemini_api_key:
            st.session_state.gemini_api_key = api_key

        # Output directory
        st.text_input(
            "Output Directory",
            value=str(st.session_state.output_dir),
            disabled=True,
            help="All generated images are saved here"
        )

        st.divider()

        st.markdown("## About")
        st.markdown(
            """
            **Character Forge** v1.0.0

            Multi-backend AI image generation with specialized tools for:
            - Character sheet creation
            - Multi-image composition
            - Text/image-to-image generation

            ---
            **License:**
            GNU AGPL v3.0

            **Privacy:**
            Your API key is stored only in YOUR session.
            It is never shared with other users.

            **Get Started:**
            - [Get API Key](https://aistudio.google.com/app/apikey)
            - [HuggingFace Space](https://huggingface.co/spaces/ghmk/character_forge)
            """
        )


def main():
    """Main application entry point."""
    # Initialize session state
    initialize_session_state()

    # Render header
    render_header()

    # Render global backend selector
    render_global_backend_selector()

    # Render sidebar
    render_sidebar()

    # Main content area
    st.info(
        """
        👈 **Select a tool from the sidebar to get started:**

        - **🔥 Character Forge**: Create multi-angle character sheets automatically
        - **🎬 Composition Assistant**: Smart multi-image composition with auto-prompts
        - **📸 Standard Interface**: Direct text-to-image and image-to-image generation

        The backend selector above applies to all tools.
        """
    )

    # Show recent generations
    if st.session_state.history:
        st.subheader("📸 Recent Generations")
        cols = st.columns(4)
        for idx, item in enumerate(st.session_state.history[-4:]):
            with cols[idx]:
                st.image(item['image'], caption=item['name'], use_container_width=True)


if __name__ == "__main__":
    main()