"""
ui/state.py
──────────────────────────────────────────────────────────────────────────────
VoiceVerse Pro — Centralised Session State & Config Contracts
"""

from __future__ import annotations

from dataclasses import dataclass, field
from enum import Enum
from typing import List, Optional

from modules import RetrievedContext, IngestedFile
from modules.tts_engine import TTSBackend


# ──────────────────────────────────────────────────────────────────────────────
# Output mode
# ──────────────────────────────────────────────────────────────────────────────

class OutputMode(str, Enum):
    TRANSCRIPT = "Audio Transcript"     # single narrator voice
    PODCAST    = "Podcast (2 Speakers)" # HOST (female) + GUEST (male) dialogue


# ──────────────────────────────────────────────────────────────────────────────
# Sidebar configuration
# ──────────────────────────────────────────────────────────────────────────────

@dataclass
class SidebarConfig:
    # Auth
    hf_token: str = ""

    # Mode
    output_mode: OutputMode = OutputMode.TRANSCRIPT

    # RAG
    top_k: int = 4
    chunk_size: int = 1000
    chunk_overlap: int = 100

    # LLM
    model_id: str = "meta-llama/Llama-3.1-8B-Instruct"
    temperature: float = 0.65
    max_tokens: int = 1024
    target_words: int = 400

    # TTS
    tts_backend: TTSBackend = TTSBackend.SPEECHT5
    # Single-speaker (transcript mode)
    speaker_id: int = 7306
    # Dual-speaker (podcast mode) — CMU Arctic xvectors
    female_speaker_id: int = 1580   # SLT-style female
    male_speaker_id: int = 7306     # BDL-style male


# ──────────────────────────────────────────────────────────────────────────────
# Pipeline state
# ──────────────────────────────────────────────────────────────────────────────

@dataclass
class PipelineState:
    """
    Single source of truth for pipeline progress.

    stage:
        0 → idle
        1 → documents indexed
        2 → context retrieved
        3 → script generated
        4 → audio synthesised
    """
    stage: int = 0

    ingested_files: List[IngestedFile] = field(default_factory=list)
    total_chunks: int = 0
    retrieved_context: Optional[RetrievedContext] = None
    generated_script: Optional[str] = None
    audio_bytes: Optional[bytes] = None
    audio_format: str = "audio/wav"

    def reset_from(self, stage: int) -> None:
        if stage <= 1:
            self.ingested_files = []; self.total_chunks = 0; self.stage = 0
        if stage <= 2:
            self.retrieved_context = None
            if self.stage >= 2: self.stage = 1
        if stage <= 3:
            self.generated_script = None
            if self.stage >= 3: self.stage = 2
        if stage <= 4:
            self.audio_bytes = None; self.audio_format = "audio/wav"
            if self.stage >= 4: self.stage = 3

    @property
    def has_index(self) -> bool: return self.stage >= 1
    @property
    def has_context(self) -> bool: return self.stage >= 2 and self.retrieved_context is not None
    @property
    def has_script(self) -> bool: return self.stage >= 3 and self.generated_script is not None
    @property
    def has_audio(self) -> bool: return self.stage >= 4 and self.audio_bytes is not None


# ──────────────────────────────────────────────────────────────────────────────
# Session bootstrap
# ──────────────────────────────────────────────────────────────────────────────

def get_pipeline_state() -> PipelineState:
    import streamlit as st
    if "pipeline_state" not in st.session_state:
        st.session_state["pipeline_state"] = PipelineState()
    if "rag_engine" not in st.session_state:
        st.session_state["rag_engine"] = None
    return st.session_state["pipeline_state"]