"""Persist a handful of user choices to ~/HVideoTool/settings.json.

For the project-based tool this file holds the **defaults for new projects** (the
detector, model path, overlay threshold, restore engine) plus app-level state: the
last opened project, the recent-projects list, and the last directory used in file
dialogs. Per-project settings live in each project's ``project.json``, not here.
"""

from __future__ import annotations

import json
from pathlib import Path

from .config import AppConfig

_PATH = Path.home() / "HVideoTool" / "settings.json"


def _read() -> dict:
    try:
        return json.loads(_PATH.read_text(encoding="utf-8"))
    except (OSError, ValueError):
        return {}


def _write(data: dict) -> None:
    _PATH.parent.mkdir(parents=True, exist_ok=True)
    _PATH.write_text(json.dumps(data, ensure_ascii=False, indent=2), encoding="utf-8")


def apply(config: AppConfig) -> None:
    """Overlay persisted settings onto ``config`` (mutates it in place)."""
    data = _read()
    if data.get("detector"):
        config.detector = data["detector"]
    if isinstance(data.get("detector_models"), list):
        config.detector_models = [str(m) for m in data["detector_models"]]
    if "threshold" in data:
        config.default_threshold = float(data["threshold"])
    if isinstance(data.get("model_thresholds"), dict):
        config.model_thresholds = {
            str(k): float(v) for k, v in data["model_thresholds"].items()
        }
    if "cross_model_nms" in data:
        config.cross_model_nms = bool(data["cross_model_nms"])
    if "nms_iou" in data:
        config.nms_iou = float(data["nms_iou"])
    if data.get("restorer"):
        config.restorer = data["restorer"]
    for key in ("dm_dir", "dm_model", "dm_gpu"):
        if key in data:
            setattr(config, key, data[key])
    if "dm_feed_restored" in data:
        config.dm_feed_restored = bool(data["dm_feed_restored"])
    # diffusion-inpaint engine
    for key in ("diff_backend", "diff_url", "diff_model", "diff_prompt", "diff_negative"):
        if key in data:
            setattr(config, key, data[key])
    if "diff_steps" in data:
        config.diff_steps = int(data["diff_steps"])
    if "diff_cfg" in data:
        config.diff_cfg = float(data["diff_cfg"])
    if "diff_denoise" in data:
        config.diff_denoise = float(data["diff_denoise"])
    if "diff_seed" in data:
        config.diff_seed = int(data["diff_seed"])
    if "diff_mask_dilate" in data:
        config.diff_mask_dilate = int(data["diff_mask_dilate"])
    if "diff_mask_blur" in data:
        config.diff_mask_blur = int(data["diff_mask_blur"])


def save(config: AppConfig) -> None:
    """Persist the configurable settings, preserving other keys (e.g. last_dir)."""
    data = _read()
    data.update(
        detector=config.detector,
        detector_models=list(config.detector_models),
        threshold=config.default_threshold,
        model_thresholds=dict(config.model_thresholds),
        cross_model_nms=config.cross_model_nms,
        nms_iou=config.nms_iou,
        restorer=config.restorer,
        dm_dir=config.dm_dir,
        dm_model=config.dm_model,
        dm_gpu=config.dm_gpu,
        dm_feed_restored=config.dm_feed_restored,
        diff_backend=config.diff_backend,
        diff_url=config.diff_url,
        diff_model=config.diff_model,
        diff_prompt=config.diff_prompt,
        diff_negative=config.diff_negative,
        diff_steps=config.diff_steps,
        diff_cfg=config.diff_cfg,
        diff_denoise=config.diff_denoise,
        diff_seed=config.diff_seed,
        diff_mask_dilate=config.diff_mask_dilate,
        diff_mask_blur=config.diff_mask_blur,
    )
    _write(data)


def last_dir() -> str | None:
    return _read().get("last_dir")


def set_last_dir(path: str) -> None:
    data = _read()
    data["last_dir"] = path
    _write(data)


def last_project() -> str | None:
    return _read().get("last_project")


def set_last_project(path: str) -> None:
    data = _read()
    data["last_project"] = path
    _write(data)


_RECENTS_CAP = 10


def recent_projects() -> list[str]:
    recents = _read().get("recent_projects", [])
    return [p for p in recents if isinstance(p, str)]


def add_recent_project(path: str) -> None:
    """Push ``path`` to the front of the recent-projects list (deduped, capped)."""
    data = _read()
    recents = [p for p in data.get("recent_projects", []) if isinstance(p, str) and p != path]
    recents.insert(0, path)
    data["recent_projects"] = recents[:_RECENTS_CAP]
    _write(data)