# -*- coding: utf-8 -*-
"""
PulseAudio / PipeWire Multi-Mic-Mix Wrapper.

Spiegelt `PulseCombinedSink` fuer die Input-Seite: mehrere
Mikrofone werden zu einer einzigen virtuellen Quelle gemischt,
sodass die Wakeword-Detection und das Server-Streaming
unveraendert mit EINER Quelle arbeiten koennen.

Technik:
    1. `module-null-sink sink_name=trixy_mics_combined`
       → erzeugt einen virtuellen Sink mit angehaengtem
         `.monitor` Source.
    2. Pro Mikrofon ein `module-loopback source=<mic> sink=trixy_mics_combined`
       → leitet das Mic-Signal in den Null-Sink.
    3. Default-Source wird auf `trixy_mics_combined.monitor`
       gesetzt, sodass alle Aufnehmer den Mix sehen.
    4. Vorheriger Default-Source wird beim Teardown wiederhergestellt.

Warum kein `module-combine-source`? Den gibt es in Pulse nicht
(nur `module-combine-sink` fuer Output). Der null-sink+loopback
Trick ist der etablierte Workaround.

Einschraenkungen: wie PulseCombinedSink. Nur verfuegbar wo
`pactl` antwortet (Linux mit Pulse/PipeWire, WSL2 mit WSLg).
"""

from __future__ import annotations

import asyncio
import os
import shutil
from typing import NamedTuple

from trixy_core.utils.debug import pinfo, pdebug, perror


class PulseSource(NamedTuple):
    """Ein einzelner PulseAudio/PipeWire Input-Source (Mikrofon)."""
    index: int
    name: str
    description: str
    state: str
    monitor_of: str  # falls es ein Monitor-Source ist, sonst ""


class PulseMicrophoneMix:
    """Verwaltet den Multi-Mic-Mix ueber pactl."""

    DEFAULT_SINK_NAME = "trixy_mics_combined"

    def __init__(self, sink_name: str = DEFAULT_SINK_NAME) -> None:
        self._sink_name = sink_name
        self._null_sink_module: int | None = None
        self._loopback_modules: list[int] = []
        self._sources: list[str] = []
        self._available: bool | None = None
        self._previous_default: str | None = None

    @property
    def sink_name(self) -> str:
        return self._sink_name

    @property
    def monitor_source_name(self) -> str:
        """Name des resultierenden virtuellen Source-Namens."""
        return f"{self._sink_name}.monitor"

    @property
    def sources(self) -> list[str]:
        return list(self._sources)

    @property
    def active(self) -> bool:
        return self._null_sink_module is not None

    async def available(self) -> bool:
        """True wenn pactl + Pulse/PipeWire-Server erreichbar sind."""
        if self._available is not None:
            return self._available
        if not shutil.which("pactl"):
            pdebug("pactl nicht gefunden — Mic-Mix deaktiviert")
            self._available = False
            return False
        rc, _ = await self._run("info")
        self._available = rc == 0
        return self._available

    # === Source-Listing ===

    async def list_sources(self, include_monitors: bool = False) -> list[PulseSource]:
        """Listet alle realen Input-Sources (ohne unseren eigenen Monitor).

        Args:
            include_monitors: Wenn False (Default), werden .monitor-Sources
                              anderer Sinks herausgefiltert — wir wollen nur
                              echte Mikrofone.
        """
        if not await self.available():
            return []
        rc, out = await self._run("list", "sources")
        if rc != 0:
            return []
        all_sources = self._parse_sources(out)

        result: list[PulseSource] = []
        for s in all_sources:
            # Eigenen Monitor ausblenden
            if s.name == self.monitor_source_name:
                continue
            # Monitor-Sources optional ausblenden
            if not include_monitors and s.monitor_of:
                continue
            result.append(s)
        return result

    @staticmethod
    def _parse_sources(text: str) -> list[PulseSource]:
        """Parst die Ausgabe von `pactl list sources`."""
        sources: list[PulseSource] = []
        current: dict = {}

        def flush() -> None:
            if not current:
                return
            try:
                sources.append(PulseSource(
                    index=int(current.get("index", -1)),
                    name=current.get("name", ""),
                    description=current.get("description", current.get("name", "")),
                    state=current.get("state", ""),
                    monitor_of=current.get("monitor_of", ""),
                ))
            except Exception:
                pass
            current.clear()

        for raw in text.splitlines():
            line = raw.rstrip()
            if line.startswith("Source #"):
                flush()
                try:
                    current["index"] = int(line.split("#", 1)[1])
                except Exception:
                    pass
                continue
            stripped = line.lstrip()
            if stripped.startswith("Name:"):
                current["name"] = stripped.split(":", 1)[1].strip()
            elif stripped.startswith("Description:"):
                current["description"] = stripped.split(":", 1)[1].strip()
            elif stripped.startswith("State:"):
                current["state"] = stripped.split(":", 1)[1].strip()
            elif stripped.startswith("Monitor of Sink:"):
                value = stripped.split(":", 1)[1].strip()
                # Pulse/PipeWire setzt "n/a" fuer Nicht-Monitor-Sources
                current["monitor_of"] = "" if value.lower() in ("n/a", "") else value
        flush()
        return sources

    # === Mix-Lifecycle ===

    async def find_existing_null_sink(self) -> int | None:
        """Sucht ein bereits geladenes module-null-sink mit unserem Namen."""
        rc, out = await self._run("list", "modules", "short")
        if rc != 0:
            return None
        for line in out.splitlines():
            parts = line.split("\t")
            if len(parts) < 2:
                continue
            try:
                idx = int(parts[0])
            except ValueError:
                continue
            module = parts[1]
            args = parts[2] if len(parts) >= 3 else ""
            if module == "module-null-sink" and f"sink_name={self._sink_name}" in args:
                return idx
        return None

    async def _find_our_loopbacks(self) -> list[int]:
        """Sucht alle loopback-Module die auf unseren Null-Sink zeigen."""
        rc, out = await self._run("list", "modules", "short")
        if rc != 0:
            return []
        result: list[int] = []
        for line in out.splitlines():
            parts = line.split("\t")
            if len(parts) < 2:
                continue
            if parts[1] != "module-loopback":
                continue
            try:
                idx = int(parts[0])
            except ValueError:
                continue
            args = parts[2] if len(parts) >= 3 else ""
            if f"sink={self._sink_name}" in args:
                result.append(idx)
        return result

    async def setup(self, sources: list[str]) -> bool:
        """Erstellt den Mic-Mix mit den gewaehlten realen Sources.

        Args:
            sources: Liste der Source-Namen die gemischt werden sollen.

        Returns:
            True bei Erfolg, False sonst.
        """
        if not await self.available():
            return False
        if not sources:
            await self.teardown()
            return False
        if len(sources) == 1:
            # Ein einzelner Mic braucht keinen Mix — Caller soll
            # den Mic direkt als Default nutzen.
            await self.teardown()
            return False

        # Aufraeumen falls etwas altes noch haengt
        await self.teardown()

        # 1. Null-Sink erstellen
        rc, out = await self._run(
            "load-module",
            "module-null-sink",
            f"sink_name={self._sink_name}",
            "sink_properties=device.description=Trixy_Multi_Mic_Mix",
        )
        if rc != 0:
            perror(f"Null-Sink konnte nicht erstellt werden: {out.strip()}")
            return False
        try:
            self._null_sink_module = int(out.strip().splitlines()[-1])
        except Exception:
            self._null_sink_module = await self.find_existing_null_sink()

        # 2. Pro Mic ein Loopback in den Null-Sink
        self._loopback_modules = []
        self._sources = []
        for source in sources:
            rc, out = await self._run(
                "load-module",
                "module-loopback",
                f"source={source}",
                f"sink={self._sink_name}",
                "latency_msec=30",
                "source_dont_move=true",
                "sink_dont_move=true",
            )
            if rc != 0:
                pdebug(f"Loopback fuer '{source}' fehlgeschlagen: {out.strip()}")
                continue
            try:
                idx = int(out.strip().splitlines()[-1])
                self._loopback_modules.append(idx)
                self._sources.append(source)
            except Exception:
                pass

        if not self._loopback_modules:
            # Kein einziger Loopback erfolgreich — Null-Sink wieder abbauen
            await self.teardown()
            return False

        pinfo(
            f"Mic-Mix aktiv: {len(self._loopback_modules)} Mikrofone → "
            f"'{self.monitor_source_name}' (Null-Sink #{self._null_sink_module})"
        )
        return True

    async def teardown(self) -> None:
        """Baut den Mix wieder ab und stellt den alten Default-Source wieder her."""
        if not await self.available():
            return

        # Vorherigen Default zuerst wiederherstellen, sonst ist er
        # kurz undefiniert wenn wir unseren .monitor-Source entladen.
        await self.restore_default_source()

        # Alle unsere Loopbacks entladen
        loopbacks = list(self._loopback_modules)
        if not loopbacks:
            # Keiner im Cache? Alle loopbacks suchen die auf uns zeigen.
            loopbacks = await self._find_our_loopbacks()
        for idx in loopbacks:
            await self._run("unload-module", str(idx))
        self._loopback_modules = []

        # Null-Sink entladen
        sink_idx = self._null_sink_module
        if sink_idx is None:
            sink_idx = await self.find_existing_null_sink()
        if sink_idx is not None:
            rc, _ = await self._run("unload-module", str(sink_idx))
            if rc == 0:
                pdebug(f"Mic-Mix Null-Sink #{sink_idx} entladen")
        self._null_sink_module = None
        self._sources = []

    # === Default-Source-Verwaltung ===

    async def get_default_source(self) -> str:
        """Liest den aktuellen System-Default-Source-Namen."""
        if not await self.available():
            return ""
        rc, out = await self._run("get-default-source")
        if rc != 0:
            return ""
        return out.strip().splitlines()[0] if out.strip() else ""

    async def set_default_source(self, source_name: str) -> bool:
        """Setzt den System-Default-Source."""
        if not await self.available():
            return False
        rc, _ = await self._run("set-default-source", source_name)
        return rc == 0

    async def make_default(self) -> bool:
        """Macht unseren Monitor zum System-Default-Source und merkt sich den vorherigen."""
        if self._null_sink_module is None:
            return False
        current = await self.get_default_source()
        if current and current != self.monitor_source_name:
            self._previous_default = current
        ok = await self.set_default_source(self.monitor_source_name)
        if ok:
            pinfo(
                f"System-Default-Source → '{self.monitor_source_name}' "
                f"(vorher: '{self._previous_default or '?'}')"
            )
        return ok

    async def restore_default_source(self) -> None:
        """Stellt den vorherigen Default-Source wieder her."""
        if not self._previous_default:
            return
        if not await self.available():
            return
        current = await self.get_default_source()
        if current == self.monitor_source_name:
            ok = await self.set_default_source(self._previous_default)
            if ok:
                pdebug(f"System-Default-Source wiederhergestellt → '{self._previous_default}'")
        self._previous_default = None

    # === Hilfsmethoden ===

    async def _run(self, *args: str) -> tuple[int, str]:
        """pactl mit LC_ALL=C damit die Ausgabe sprachunabhaengig ist."""
        env = os.environ.copy()
        env["LC_ALL"] = "C"
        env["LANG"] = "C"
        try:
            proc = await asyncio.create_subprocess_exec(
                "pactl", *args,
                stdout=asyncio.subprocess.PIPE,
                stderr=asyncio.subprocess.STDOUT,
                env=env,
            )
            stdout, _ = await proc.communicate()
            return proc.returncode or 0, stdout.decode(errors="replace")
        except FileNotFoundError:
            return 127, ""
        except Exception as e:
            perror(f"pactl Fehler: {e}")
            return 1, str(e)