from __future__ import annotations

from functools import lru_cache
from pathlib import Path

import yaml
from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict

ROOT = Path(__file__).resolve().parents[2]


class AppSettings(BaseSettings):
    model_config = SettingsConfigDict(
        env_file=str(ROOT / ".env"),
        env_file_encoding="utf-8",
        extra="ignore",
    )

    tts_model: str = Field(default="cosyvoice", validation_alias="TTS_MODEL")
    host: str = Field(default="0.0.0.0", validation_alias="TTS_HOST")
    port: int = Field(default=8000, validation_alias="TTS_PORT")
    samples_dir: Path = Field(default=ROOT / "samples")
    outputs_dir: Path = Field(default=ROOT / "outputs" / "api")
    uploads_dir: Path = Field(default=ROOT / "backend" / "data" / "uploads")
    default_ref_audio: str | None = Field(default=None, validation_alias="TTS_REF_AUDIO")
    default_ref_text: str | None = Field(default=None, validation_alias="TTS_REF_TEXT")
    cosyvoice_model_dir: Path = Field(default=ROOT / "models" / "Fun-CosyVoice3-0.5B")
    cosyvoice_prompt_prefix: str = (
        "You are a helpful assistant.<|endofprompt|>"
    )
    chunk_max_chars: int = 120


@lru_cache
def get_settings() -> AppSettings:
    yaml_path = ROOT / "config" / "settings.yaml"
    data: dict = {}
    if yaml_path.is_file():
        with open(yaml_path, encoding="utf-8") as f:
            raw = yaml.safe_load(f) or {}
        data["tts_model"] = raw.get("default_model", "cosyvoice")
        gen = raw.get("generation") or {}
        data["chunk_max_chars"] = gen.get("chunk_max_chars", 120)
        cv = raw.get("cosyvoice") or {}
        if cv.get("model_dir"):
            data["cosyvoice_model_dir"] = ROOT / cv["model_dir"]
        if cv.get("prompt_prefix"):
            data["cosyvoice_prompt_prefix"] = cv["prompt_prefix"]
        srv = raw.get("server") or {}
        data["host"] = srv.get("host", "0.0.0.0")
        data["port"] = srv.get("port", 8000)
        paths = raw.get("paths") or {}
        if paths.get("samples_dir"):
            data["samples_dir"] = ROOT / paths["samples_dir"]
        if paths.get("outputs_dir"):
            data["outputs_dir"] = ROOT / paths["outputs_dir"] / "api"
        if paths.get("uploads_dir"):
            data["uploads_dir"] = ROOT / paths["uploads_dir"]

    return AppSettings(**{k: v for k, v in data.items() if v is not None})


def project_root() -> Path:
    return ROOT