from __future__ import annotations

import json
from pathlib import Path
from typing import Optional

SAMPLES_DIR = Path(__file__).resolve().parent.parent / "assets" / "samples" / "kbsim"
MANIFEST_PATH = SAMPLES_DIR / "manifest.json"
DEFAULT_RELEASE_OFFSET = 0.08

SPECIAL_KEY_SAMPLES: dict[str, str] = {
    "Space": "SPACE",
    "Enter": "ENTER",
    "Backspace": "BACKSPACE",
}


def _load_manifest() -> dict[str, dict[str, list[str]]]:
    with MANIFEST_PATH.open(encoding="utf-8") as f:
        return json.load(f)


MANIFEST = _load_manifest()


def hash_code(value: str) -> int:
    """djb2 hash — mirrored in frontend/src/lib/audio/keySoundMap.ts"""
    hash_val = 5381
    for ch in value:
        hash_val = ((hash_val * 33) ^ ord(ch)) & 0xFFFFFFFF
    return hash_val


def press_variant_index(code: str) -> int:
    return hash_code(code) % 5


def press_variant_key(code: str) -> str:
    return f"GENERIC_R{press_variant_index(code)}"


def resolve_press_sample_key(key_label: str, code: str, available: list[str]) -> str:
    special = SPECIAL_KEY_SAMPLES.get(key_label)
    if special and special in available:
        return special
    variant = press_variant_key(code)
    if variant in available:
        return variant
    for sample in available:
        if sample.startswith("GENERIC_R"):
            return sample
    return available[0]


def resolve_release_sample_key(key_label: str, available: list[str]) -> str:
    special = SPECIAL_KEY_SAMPLES.get(key_label)
    if special and special in available:
        return special
    if "GENERIC" in available:
        return "GENERIC"
    return available[0]


def sample_path(switch_id: str, phase: str, sample_key: str) -> Path:
    return SAMPLES_DIR / switch_id / phase / f"{sample_key}.mp3"


def marker_release_time(time: float, release_time: Optional[float]) -> float:
    return release_time if release_time is not None else time + DEFAULT_RELEASE_OFFSET


def resolve_marker_samples(
    switch_id: str,
    key_label: str,
    code: Optional[str],
) -> tuple[str, str]:
    switch_manifest = MANIFEST[switch_id]
    press_available = switch_manifest["press"]
    release_available = switch_manifest["release"]
    resolved_code = code or key_label
    press_key = resolve_press_sample_key(key_label, resolved_code, press_available)
    release_key = resolve_release_sample_key(key_label, release_available)
    return press_key, release_key