"""Shared helpers for the backend setup wizards.

Every TTS backend setup wizard (audio.cpp, qwen, faster) lives in its own
module under ``backends``; this module holds the pieces more than one of
them needs: .wav discovery, path normalization, and the regex edit that
keeps ``converter/config.py`` in sync with the choices made in a wizard.
It deliberately imports nothing from the other backend modules (or the
TUI) so it can be reused without pulling curses into a non-interactive
run.
"""

import os
import re
import urllib.parse
from pathlib import Path
from typing import Dict, List, Optional, Set, Tuple

# The tts-audiobook-generator checkout root (where audiobook.py lives).
# Backend checkouts are cloned into subdirectories of this root
# (./audio.cpp, ./faster-qwen3-tts) so a single tree holds everything.
TTS_ROOT = Path(__file__).resolve().parent.parent

# The project's sample-voice directory: .wav files dropped here are offered
# as the default source when a setup/configure wizard asks for a wav
# directory (both the TUI browser start and the --wavs flag default).
VOICES_DIR = TTS_ROOT / "voices"

# converter/config.py — rewritten in place by update_config_value so the
# converter picks up the host/port/voice a wizard configured.
CONFIG_PATH = TTS_ROOT / "converter" / "config.py"

# Output directory of tts-audiobook-generator; never offered as a .wav
# source by detect_wav_dir.
TTS_OUTPUT_DIR = "output"

# The voice-transcript mapping file audio.cpp reads from its voice_dir.
# (The faster backend uses voices.json instead; see backends.faster.)
PROMPT_TEXT_FILENAME = "prompt_text"


def normalize_dir_arg(value: str) -> Path:
    """Normalize a user-supplied path argument.

    Strips surrounding quotes (a common copy-paste artifact), expands a
    leading ``~``, and resolves the result to an absolute path so relative
    paths are always validated against the current working directory.
    """
    cleaned = value.strip()
    if len(cleaned) >= 2 and cleaned[0] == cleaned[-1] and cleaned[0] in "\"'":
        cleaned = cleaned[1:-1]
    return Path(os.path.expanduser(cleaned)).resolve()


def resolve_wav_dir_arg(value: str) -> Path:
    """Normalize a user-supplied wav directory argument."""
    return normalize_dir_arg(value)


def find_wav_files(input_dir: Path) -> List[Path]:
    """Return the .wav files in INPUT_DIR, sorted alphabetically by name."""
    return sorted(
        (path for path in input_dir.iterdir()
         if path.is_file() and path.suffix.lower() == ".wav"),
        key=lambda path: path.name.lower(),
    )


def count_wavs(directory: Path) -> int:
    """Count the .wav files in DIRECTORY (0 when it cannot be read)."""
    try:
        return sum(1 for path in directory.iterdir()
                   if path.is_file() and path.suffix.lower() == ".wav")
    except OSError:
        return 0


def detect_wav_dir(audiocpp_dir: Path, tts_root: Path) -> Optional[Path]:
    """Find a unique directory that directly contains .wav files.

    Looks shallowly (the root itself and its immediate subdirectories) in
    both the audio.cpp checkout and the tts-audiobook-generator root (where
    audiobook.py lives), since clone reference .wavs commonly live in
    either. The tts-audiobook-generator ``output/`` directory is excluded.
    When exactly one candidate is found it is returned (as a starting
    directory for the .wav browser); when none or several are found None is
    returned so the caller falls back to its default start location.
    """
    candidates: List[Path] = []
    seen: Set[Path] = set()

    def consider(directory: Path) -> None:
        try:
            resolved = directory.resolve()
        except OSError:
            return
        if resolved in seen:
            return
        seen.add(resolved)
        if count_wavs(directory) > 0:
            candidates.append(directory)

    for root in (audiocpp_dir, tts_root):
        if not root.is_dir():
            continue
        consider(root)
        try:
            children = sorted(root.iterdir(), key=lambda p: p.name.lower())
        except OSError:
            continue
        for child in children:
            if not child.is_dir() or child.name.startswith("."):
                continue
            if root == tts_root and child.name == TTS_OUTPUT_DIR:
                continue
            consider(child)

    if len(candidates) == 1:
        return candidates[0]
    return None


def wav_dir_info(directory: Path) -> Tuple[str, str]:
    """TUI status describing the directory listed in the wav browser."""
    count = count_wavs(directory)
    if count:
        wavs = ".wav" if count == 1 else ".wavs"
        return (f"{count} {wavs} found in this directory. Press Enter.",
                "ok")
    return ("No .wav files found in this directory", "warn")


def wav_dir_preview(directory: Path) -> Tuple[str, str]:
    """TUI status describing a highlighted subdirectory in the wav browser."""
    count = count_wavs(directory)
    if count:
        wavs = ".wav" if count == 1 else ".wavs"
        return (f"{count} {wavs}", "ok")
    return ("no .wav files", "info")


def url_with_port(url: str, port: int) -> str:
    """Return URL with its port replaced/inserted as PORT."""
    parts = urllib.parse.urlsplit(url)
    host = parts.hostname or "127.0.0.1"
    return urllib.parse.urlunsplit(
        (parts.scheme or "http", f"{host}:{port}", parts.path, "", ""))


def server_running(url: str, timeout: float = 0.3) -> bool:
    """True when something accepts TCP connections at URL's host:port.

    A protocol-agnostic socket connect: an HTTP TTS server that is up will
    accept the connection (we do not need to speak HTTP to know it is
    listening). Returns False on any parse or connection error, so a
    misconfigured URL never blocks the hub — it just reports the backend
    as not running. Used by each backend's ``detect()`` to set
    ``BackendStatus.running``.
    """
    import socket
    try:
        parts = urllib.parse.urlsplit(url)
        host = parts.hostname or "127.0.0.1"
        port = parts.port or (443 if (parts.scheme or "http") == "https"
                              else 80)
    except ValueError:
        return False
    try:
        with socket.create_connection((host, port), timeout=timeout):
            return True
    except OSError:
        return False


def update_config_value(key: str, value: str,
                        config_path: Optional[Path] = None) -> bool:
    """Rewrite a ``KEY = "value"`` line in converter/config.py.

    Only the quoted literal is replaced; surrounding lines and the trailing
    comment are preserved. Returns True when the file was changed. Used by
    the qwen and faster wizards to keep their API URL / voice / speaker
    settings in sync with the converter.
    """
    path = Path(config_path) if config_path is not None else CONFIG_PATH
    try:
        text = path.read_text(encoding="utf-8")
    except OSError:
        return False
    match = re.search(r'(?m)^(\s*' + re.escape(key) + r'\s*=\s*")([^"]*)(")',
                      text)
    if not match or match.group(2) == value:
        return False
    text = text[:match.start(2)] + value + text[match.end(2):]
    try:
        path.write_text(text, encoding="utf-8")
    except OSError:
        return False
    return True


def read_prompt_text(prompt_path: Path) -> Dict[str, str]:
    """Parse a prompt_text file into a stem -> transcript mapping.

    Lines are ``<name>|<transcript>``; blank lines are skipped and a line
    without a ``|`` separator is treated as a name with an empty transcript.
    Returns an empty mapping when the file does not exist.
    """
    if not prompt_path.exists():
        return {}
    mapping: Dict[str, str] = {}
    for line in prompt_path.read_text(encoding="utf-8").splitlines():
        if not line.strip():
            continue
        if "|" in line:
            name, _, text = line.partition("|")
        else:
            name, text = line, ""
        mapping[name.strip()] = text
    return mapping


def write_prompt_text(wav_dir: Path,
                      transcripts: Dict[str, str]) -> Path:
    """Write the voice_dir prompt_text mapping into WAV_DIR.

    One ``<basename-without-extension>|<transcript>`` line per voice.
    Returns the path of the written file.
    """
    prompt_path = wav_dir / PROMPT_TEXT_FILENAME
    lines = [f"{name}|{text}" for name, text in transcripts.items()]
    prompt_path.write_text("\n".join(lines) + "\n", encoding="utf-8")
    return prompt_path


def run_console_subprocess(argv: List[str], cwd: Optional[Path] = None) -> int:
    """Run a subprocess whose output streams to the plain console.

    Used inside ``tui.suspend`` for clone/build/pip steps: the caller has
    already left curses mode, so the child inherits the real terminal and
    its output appears normally. Returns the process exit code.
    """
    import subprocess
    try:
        result = subprocess.run(argv, cwd=str(cwd) if cwd is not None else None)
    except OSError as exc:
        print(f"[ERROR] Could not run {' '.join(argv)}: {exc}")
        return 1
    return result.returncode


def git_clone(url: str, target: Path) -> int:
    """Clone URL into TARGET, streaming to the console. Returns exit code."""
    print(f"[INFO] Cloning {url} into {target}...")
    return run_console_subprocess(["git", "clone", url, str(target)])


def pip_install(packages: List[str]) -> int:
    """pip install PACKAGES into the managed venv (``envs/tts``). Returns exit code.

    Delegates to ``backends.envs.pip_install`` so backend TTS packages are
    installed alongside the app requirements in the tool-managed environment
    rather than into whatever interpreter happens to be running the wizard.
    The import is local to avoid a circular import (envs imports this module).
    """
    from backends import envs
    return envs.pip_install(packages)