#!/usr/bin/env python3

import json
import os
import shlex
import sys
from pathlib import Path


DEFAULT_TEXT_OCR_CONFIG = {
    "det_model_name": "db_shufflenet_v2_small",
    "det_model_backend": "pytorch",
    "rec_model_name": "doc-densenet_lite_136-gru",
    "rec_model_backend": "onnx",
}
DEFAULT_CPU_THREADS = "2"
THREAD_ENV_DEFAULTS = {
    "OMP_NUM_THREADS": DEFAULT_CPU_THREADS,
    "OPENBLAS_NUM_THREADS": DEFAULT_CPU_THREADS,
    "MKL_NUM_THREADS": DEFAULT_CPU_THREADS,
    "NUMEXPR_NUM_THREADS": DEFAULT_CPU_THREADS,
    "VECLIB_MAXIMUM_THREADS": DEFAULT_CPU_THREADS,
}


def env_flag(name: str, default: bool = False) -> bool:
    value = os.environ.get(name)
    if value is None:
        return default
    return value.strip().lower() in {"1", "true", "yes", "on"}


def default_cache_root() -> Path:
    explicit_root = os.environ.get("PIX2TEXT_CACHE_ROOT")
    if explicit_root:
        return Path(explicit_root)

    persistent_root = Path("/data/pix2text-demo")
    if persistent_root.parent.exists() and os.access(persistent_root.parent, os.W_OK):
        return persistent_root

    return Path("/tmp/pix2text-demo")


def configure_runtime_dirs() -> None:
    cache_root = default_cache_root()
    dir_map = {
        "HF_HOME": cache_root / "huggingface",
        "XDG_CACHE_HOME": cache_root / "xdg-cache",
        "MPLCONFIGDIR": cache_root / "matplotlib",
        "YOLO_CONFIG_DIR": cache_root / "ultralytics",
        "PIX2TEXT_HOME": cache_root / "pix2text",
        "CNOCR_HOME": cache_root / "cnocr",
        "CNSTD_HOME": cache_root / "cnstd",
    }
    for env_name, path in dir_map.items():
        os.environ.setdefault(env_name, str(path))
        Path(os.environ[env_name]).mkdir(parents=True, exist_ok=True)

    output_root = Path(os.environ.get("P2T_OUTPUT_MD_ROOT_DIR", "/tmp/pix2text-output"))
    output_root.mkdir(parents=True, exist_ok=True)


def configure_cpu_threads() -> None:
    for env_name, value in THREAD_ENV_DEFAULTS.items():
        os.environ.setdefault(env_name, value)


def build_ui_command(host: str, port: str) -> list[str]:
    os.environ.setdefault("STREAMLIT_BROWSER_GATHER_USAGE_STATS", "false")
    os.environ.setdefault("STREAMLIT_SERVER_HEADLESS", "true")
    os.environ.setdefault("STREAMLIT_SERVER_ENABLE_XSRF_PROTECTION", "false")
    return [
        sys.executable,
        "-m",
        "streamlit",
        "run",
        "pix2text/app.py",
        "--server.address",
        host,
        "--server.port",
        port,
        "--server.enableXsrfProtection=false",
    ]


def build_api_command(host: str, port: str) -> list[str]:
    cmd = [
        sys.executable,
        "-m",
        "pix2text.cli",
        "serve",
        "-l",
        os.environ.get("P2T_LANGUAGES", "en"),
        "--text-ocr-config",
        os.environ.get(
            "P2T_TEXT_OCR_CONFIG",
            json.dumps(DEFAULT_TEXT_OCR_CONFIG, separators=(",", ":")),
        ),
        "--device",
        os.environ.get("P2T_DEVICE", "cpu"),
        "-o",
        os.environ.get("P2T_OUTPUT_MD_ROOT_DIR", "/tmp/pix2text-output"),
        "-H",
        host,
        "-p",
        port,
        "--log-level",
        os.environ.get("P2T_LOG_LEVEL", "INFO"),
    ]

    optional_json_args = {
        "P2T_LAYOUT_CONFIG": "--layout-config",
        "P2T_MFD_CONFIG": "--mfd-config",
        "P2T_FORMULA_OCR_CONFIG": "--formula-ocr-config",
    }
    for env_name, cli_flag in optional_json_args.items():
        value = os.environ.get(env_name)
        if value:
            cmd.extend([cli_flag, value])

    cmd.append("--enable-formula" if env_flag("P2T_ENABLE_FORMULA", False) else "--disable-formula")
    cmd.append("--enable-table" if env_flag("P2T_ENABLE_TABLE", False) else "--disable-table")
    if env_flag("P2T_RELOAD", False):
        cmd.append("--reload")
    return cmd


def main() -> int:
    configure_runtime_dirs()
    configure_cpu_threads()

    app_mode = os.environ.get("P2T_APP_MODE", "ui").strip().lower()
    host = os.environ.get("HOST", os.environ.get("P2T_HOST", "0.0.0.0"))
    port = os.environ.get("PORT") or os.environ.get("P2T_PORT") or "7860"

    if app_mode == "ui":
        cmd = build_ui_command(host, port)
    elif app_mode == "api":
        cmd = build_api_command(host, port)
    else:
        raise SystemExit(
            f"Unsupported P2T_APP_MODE={app_mode!r}. Use 'ui' or 'api'."
        )

    if env_flag("P2T_DRY_RUN", False):
        print(" ".join(shlex.quote(part) for part in cmd))
        return 0

    os.execvpe(cmd[0], cmd, os.environ)
    return 0


if __name__ == "__main__":
    raise SystemExit(main())