"""Dependency-light audio placeholder for Day 1 pipeline proof."""

from __future__ import annotations

import math
import wave
from pathlib import Path

from .schema import Delivery, Script

SAMPLE_RATE = 24_000

_DELIVERY_FREQ = {
    Delivery.NEUTRAL: 330,
    Delivery.SLOW: 262,
    Delivery.URGENT: 494,
    Delivery.WHISPER: 220,
    Delivery.BOOMING: 165,
    Delivery.DEADPAN: 294,
    Delivery.AGITATED: 440,
}


def render_placeholder_wav(script: Script, output_path: Path) -> Path:
    """Render a rough tone timeline so orchestration has a real file artifact."""
    script.validate()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    samples: list[int] = []
    samples.extend(_tone(196, 0.5, 0.28))
    samples.extend(_silence(0.15))
    for scene in script.scenes:
        samples.extend(_noise_burst(0.18))
        samples.extend(_silence(0.15))
        for line in scene.lines:
            duration = min(max(len(line.text) / 34.0, 0.65), 2.4)
            samples.extend(_tone(_DELIVERY_FREQ[line.delivery], duration, 0.22))
            samples.extend(_silence(0.18))
        samples.extend(_silence(0.35))
    samples.extend(_tone(147, 0.8, 0.24))

    with wave.open(str(output_path), "wb") as wav:
        wav.setnchannels(1)
        wav.setsampwidth(2)
        wav.setframerate(SAMPLE_RATE)
        wav.writeframes(b"".join(sample.to_bytes(2, "little", signed=True) for sample in samples))
    return output_path


def _tone(freq: float, seconds: float, gain: float) -> list[int]:
    count = int(SAMPLE_RATE * seconds)
    attack = max(1, int(SAMPLE_RATE * 0.02))
    release = max(1, int(SAMPLE_RATE * 0.03))
    out = []
    for i in range(count):
        envelope = 1.0
        if i < attack:
            envelope = i / attack
        elif i > count - release:
            envelope = max(0.0, (count - i) / release)
        value = math.sin(2 * math.pi * freq * (i / SAMPLE_RATE))
        out.append(int(32767 * gain * envelope * value))
    return out


def _silence(seconds: float) -> list[int]:
    return [0] * int(SAMPLE_RATE * seconds)


def _noise_burst(seconds: float) -> list[int]:
    count = int(SAMPLE_RATE * seconds)
    out = []
    seed = 17
    for i in range(count):
        seed = (1103515245 * seed + 12345) & 0x7FFFFFFF
        envelope = max(0.0, 1.0 - i / count)
        value = ((seed / 0x7FFFFFFF) * 2.0) - 1.0
        out.append(int(32767 * 0.08 * envelope * value))
    return out