"""Per-source quality mappers — turn each download source's tier string or
API values into a unified :class:`~core.quality.model.AudioQuality`.

Every streaming source describes quality differently (Tidal/HiFi use tier
strings, Qobuz reports real kHz + bit depth, Deezer uses config codes,
Amazon mixes real values with HD/UHD tiers). Centralising the knowledge
here keeps the per-client code to a single call and keeps the tier tables
in one auditable place.

Each value is a *claim*: the download client populates its ``TrackResult``
from it so the global ranker can choose a source, and the post-download
quality guard later verifies the real file. Over-claiming is the danger —
an unknown tier maps to ``format='unknown'`` rather than pretending to be
lossless.
"""

from __future__ import annotations

from typing import Optional

from core.quality.model import AudioQuality


# ── Tidal / HiFi (Monochrome is Tidal-backed) ──────────────────────────────
#
# Tidal exposes UPPER_SNAKE tier strings (``HI_RES_LOSSLESS``); HiFi's config
# uses lowercase keys (``hires``/``lossless``). We normalise both into the
# same lookup so one mapper serves both sources.

_TIDAL_HIRES = AudioQuality(format='flac', sample_rate=96000, bit_depth=24)
_TIDAL_LOSSLESS = AudioQuality(format='flac', sample_rate=44100, bit_depth=16)
_TIDAL_HIGH = AudioQuality(format='aac', bitrate=320)
_TIDAL_LOW = AudioQuality(format='aac', bitrate=96)

TIDAL_TIER_MAP = {
    'HI_RES_LOSSLESS': _TIDAL_HIRES,
    'HI_RES': _TIDAL_HIRES,
    'HIRES': _TIDAL_HIRES,
    'LOSSLESS': _TIDAL_LOSSLESS,
    'HIGH': _TIDAL_HIGH,
    'LOW': _TIDAL_LOW,
}


def quality_from_tidal_tier(tier: str) -> AudioQuality:
    """Map a Tidal/HiFi quality tier string to an AudioQuality.

    Case-insensitive; accepts both ``HI_RES`` and ``hires`` spellings.
    Unrecognised tiers map to ``format='unknown'`` so they never
    over-claim lossless quality.
    """
    key = (tier or '').strip().upper()
    return TIDAL_TIER_MAP.get(key, AudioQuality(format='unknown'))


# ── Qobuz (real API values) ────────────────────────────────────────────────

def quality_from_qobuz(sampling_rate_khz: float, bit_depth: int) -> AudioQuality:
    """Qobuz reports ``maximum_sampling_rate`` in kHz (e.g. 44.1, 96, 192)
    and ``maximum_bit_depth``. These are real values from the API.
    """
    sample_rate = int(round(sampling_rate_khz * 1000)) if sampling_rate_khz else None
    return AudioQuality(format='flac', sample_rate=sample_rate, bit_depth=bit_depth)


# ── Deezer (config code) ───────────────────────────────────────────────────

DEEZER_CODE_MAP = {
    'flac': AudioQuality(format='flac', sample_rate=44100, bit_depth=16),
    'mp3_320': AudioQuality(format='mp3', bitrate=320),
    'mp3_128': AudioQuality(format='mp3', bitrate=128),
}


def quality_from_deezer(code: str) -> AudioQuality:
    """Map a Deezer download quality code to AudioQuality.

    Deezer FLAC is always CD-quality (16-bit/44.1 kHz).
    """
    return DEEZER_CODE_MAP.get((code or '').lower(), AudioQuality(format='unknown'))


# ── Amazon Music (real sampleRate preferred, HD/UHD tier fallback) ─────────

_AMAZON_TIER_MAP = {
    'UHD': AudioQuality(format='flac', sample_rate=96000, bit_depth=24),
    'HD': AudioQuality(format='flac', sample_rate=44100, bit_depth=16),
}


def quality_from_amazon(
    tier: str,
    sample_rate: Optional[int] = None,
    bit_depth: Optional[int] = None,
) -> AudioQuality:
    """Amazon Music is FLAC; prefer the real ``sampleRate``/``bitDepth`` from
    the stream info when present, otherwise fall back to the HD/UHD tier.
    """
    base = _AMAZON_TIER_MAP.get((tier or '').strip().upper(), AudioQuality(format='flac'))
    return AudioQuality(
        format='flac',
        sample_rate=sample_rate if sample_rate is not None else base.sample_rate,
        bit_depth=bit_depth if bit_depth is not None else base.bit_depth,
    )