"""Centralised session-state initialisation for the Streamlit app.

All keys used throughout the app are declared here with their default values.
Calling init_state() at the top of app.py ensures every key exists before any
page tries to read it, preventing KeyError on the first load.
"""

import streamlit as st
from backend.managers.chat_manager import ChatManager


def init_state():
    # Sidebar state initialization
    # last_selected tracks the previously clicked tree node to detect new clicks
    if "last_selected" not in st.session_state:
        st.session_state.last_selected = None

    # Absolute path and workspace-relative path of the currently highlighted folder
    if "selected_folder" not in st.session_state:
        st.session_state.selected_folder = None

    if "selected_folder_rel" not in st.session_state:
        st.session_state.selected_folder_rel = None

    # Chat manager (persists across reruns)
    # ChatManager keeps the full conversation history in memory across reruns
    if "chat_manager" not in st.session_state:
        st.session_state.chat_manager = ChatManager()

    # Editor state initialization
    # List of absolute file paths that are currently open as tabs
    if "open_files" not in st.session_state:
        """A list of currently open file paths - absolute paths only. The order determines the tab order in the UI.
        Format: [ "path/to/file1.py", "path/to/file2.js", ... ]
        """
        st.session_state.open_files = []

    # Dict mapping file path → current editor content (may be unsaved)
    if "files_content" not in st.session_state:
        """A dictionary mapping file paths to their current content in the editor.
        Format: { "path/to/file.py": "file content as string", ... }
        """
        st.session_state.files_content = {}

    # Absolute path of the file whose tab is currently active
    if "active_file" not in st.session_state:
        """The currently active file in the editor (absolute path in string e.g. "/workspace/path/to/file.py"). 
        Should be one of the paths in open_files or None if no file is open."""
        st.session_state.active_file = None

    # Index of the active tab (used by st.tabs)
    if "active_tab" not in st.session_state:
        st.session_state.active_tab = 0

    if "is_editing" not in st.session_state:
        st.session_state.is_editing = False

    if "code_suggestions" not in st.session_state:
        st.session_state.code_suggestions = []

    # Output dict from the last code run: {stdout, stderr, return_code}
    if "code_execution_output" not in st.session_state:
        st.session_state.code_execution_output = ""

    # Chat state initialization
    # Flat list of {"role": ..., "content": ...} dicts shown as chat bubbles
    if "chat_history" not in st.session_state:
        st.session_state.chat_history = []

    # Agent Mode state
    # Whether the UI is currently in Agent Mode (vs normal chat)
    if "agent_mode" not in st.session_state:
        st.session_state.agent_mode = False

    # The live CodingAgent instance while a task is running
    if "coding_agent" not in st.session_state:
        st.session_state.coding_agent = None

    # Current status of the agent: "idle" | "waiting_approval" | "done"
    if "agent_status" not in st.session_state:
        st.session_state.agent_status = "idle"

    # List of completed steps shown in the collapsible Agent Log
    if "agent_log" not in st.session_state:
        st.session_state.agent_log = []

    # The action the agent proposed but has not yet been approved or rejected
    if "agent_pending_action" not in st.session_state:
        st.session_state.agent_pending_action = None

    # Web search results to be injected as context into the next AI message.
    # List of {"title": str, "url": str, "snippet": str} dicts, or empty list.
    if "search_results" not in st.session_state:
        st.session_state.search_results = []



if __name__ == "__main__":
    init_state()