#!/usr/bin/env python3

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0

"""Cross-platform Python dependency installer for Unsloth Studio.

Called by both setup.sh (Linux / WSL) and setup.ps1 (Windows) after the
virtual environment is already activated.  Expects `pip` and `python` on
PATH to point at the venv.
"""

from __future__ import annotations

import os
import shutil
import subprocess
import sys
import tempfile
import urllib.request
from pathlib import Path

IS_WINDOWS = sys.platform == "win32"

# -- Verbosity control ----------------------------------------------------------
# By default the installer shows a minimal progress bar (one line, in-place).
# Set UNSLOTH_VERBOSE=1 in the environment to restore full per-step output:
#   Linux/Mac:  UNSLOTH_VERBOSE=1 ./studio/setup.sh
#   Windows:    $env:UNSLOTH_VERBOSE="1" ; .\studio\setup.ps1
VERBOSE: bool = os.environ.get("UNSLOTH_VERBOSE", "0") == "1"

# Progress bar state -- updated by _progress() as each install step runs.
# _TOTAL counts: pip-upgrade + 7 shared steps + triton (non-Windows) + local-plugin + finalize
# Update _TOTAL here if you add or remove install steps in install_python_stack().
_STEP: int = 0
_TOTAL: int = 0  # set at runtime in install_python_stack() based on platform

# -- Paths --------------------------------------------------------------
SCRIPT_DIR = Path(__file__).resolve().parent
REQ_ROOT = SCRIPT_DIR / "backend" / "requirements"
SINGLE_ENV = REQ_ROOT / "single-env"
CONSTRAINTS = SINGLE_ENV / "constraints.txt"
LOCAL_DD_UNSTRUCTURED_PLUGIN = (
    SCRIPT_DIR / "backend" / "plugins" / "data-designer-unstructured-seed"
)

# -- Unicode-safe printing ---------------------------------------------
# On Windows the default console encoding can be a legacy code page
# (e.g. CP1252) that cannot represent Unicode glyphs such as ✅ or ❌.
# _safe_print() gracefully degrades to ASCII equivalents so the
# installer never crashes just because of a status glyph.

_UNICODE_TO_ASCII: dict[str, str] = {
    "\u2705": "[OK]",  # ✅
    "\u274c": "[FAIL]",  # ❌
    "\u26a0\ufe0f": "[!]",  # ⚠️  (warning + variation selector)
    "\u26a0": "[!]",  # ⚠  (warning without variation selector)
}


def _safe_print(*args: object, **kwargs: object) -> None:
    """Drop-in print() replacement that survives non-UTF-8 consoles."""
    try:
        print(*args, **kwargs)
    except UnicodeEncodeError:
        # Stringify, then swap emoji for ASCII equivalents
        text = " ".join(str(a) for a in args)
        for uni, ascii_alt in _UNICODE_TO_ASCII.items():
            text = text.replace(uni, ascii_alt)
        # Final fallback: replace any remaining unencodable chars
        print(
            text.encode(sys.stdout.encoding or "ascii", errors = "replace").decode(
                sys.stdout.encoding or "ascii", errors = "replace"
            ),
            **kwargs,
        )


# -- Color support ------------------------------------------------------


def _enable_colors() -> bool:
    """Try to enable ANSI color support. Returns True if available."""
    if not hasattr(sys.stdout, "fileno"):
        return False
    try:
        if not os.isatty(sys.stdout.fileno()):
            return False
    except Exception:
        return False
    if IS_WINDOWS:
        try:
            import ctypes

            kernel32 = ctypes.windll.kernel32
            # Enable ENABLE_VIRTUAL_TERMINAL_PROCESSING (0x0004) on stdout
            handle = kernel32.GetStdHandle(-11)  # STD_OUTPUT_HANDLE
            mode = ctypes.c_ulong()
            kernel32.GetConsoleMode(handle, ctypes.byref(mode))
            kernel32.SetConsoleMode(handle, mode.value | 0x0004)
            return True
        except Exception:
            return False
    return True  # Unix terminals support ANSI by default


# Colors disabled -- Colab and most CI runners render ANSI fine, but plain output
# is cleaner in the notebook cell. Re-enable by setting _HAS_COLOR = _enable_colors()
_HAS_COLOR = False


def _green(msg: str) -> str:
    return f"\033[92m{msg}\033[0m" if _HAS_COLOR else msg


def _cyan(msg: str) -> str:
    return f"\033[96m{msg}\033[0m" if _HAS_COLOR else msg


def _red(msg: str) -> str:
    return f"\033[91m{msg}\033[0m" if _HAS_COLOR else msg


def _progress(label: str) -> None:
    """Print an in-place progress bar for the current install step.

    Uses only stdlib (sys.stdout) -- no extra packages required.
    In VERBOSE mode this is a no-op; per-step labels are printed by run() instead.
    """
    global _STEP
    _STEP += 1
    if VERBOSE:
        return  # verbose mode: run() already printed the label
    width = 20
    filled = int(width * _STEP / _TOTAL)
    bar = "=" * filled + "-" * (width - filled)
    end = "\n" if _STEP >= _TOTAL else ""  # newline only on the final step
    sys.stdout.write(f"\r[{bar}] {_STEP:2}/{_TOTAL}  {label:<40}{end}")
    sys.stdout.flush()


def run(
    label: str, cmd: list[str], *, quiet: bool = True
) -> subprocess.CompletedProcess[bytes]:
    """Run a command; on failure print output and exit."""
    if VERBOSE:
        print(f"   {label}...")
    result = subprocess.run(
        cmd,
        stdout = subprocess.PIPE if quiet else None,
        stderr = subprocess.STDOUT if quiet else None,
    )
    if result.returncode != 0:
        _safe_print(_red(f"❌ {label} failed (exit code {result.returncode}):"))
        if result.stdout:
            print(result.stdout.decode(errors = "replace"))
        sys.exit(result.returncode)
    return result


# Packages to skip on Windows (require special build steps)
WINDOWS_SKIP_PACKAGES = {"open_spiel", "triton_kernels"}

# -- uv bootstrap ------------------------------------------------------

USE_UV = False  # Set by _bootstrap_uv() at the start of install_python_stack()
UV_NEEDS_SYSTEM = False  # Set by _bootstrap_uv() via probe


def _bootstrap_uv() -> bool:
    """Check if uv is available and probe whether --system is needed."""
    global UV_NEEDS_SYSTEM
    if not shutil.which("uv"):
        return False
    # Probe: try a dry-run install targeting the current Python explicitly.
    # Without --python, uv can ignore the activated venv on some platforms.
    probe = subprocess.run(
        ["uv", "pip", "install", "--dry-run", "--python", sys.executable, "pip"],
        stdout = subprocess.PIPE,
        stderr = subprocess.STDOUT,
    )
    if probe.returncode != 0:
        # Retry with --system (some envs need it when uv can't find a venv)
        probe_sys = subprocess.run(
            ["uv", "pip", "install", "--dry-run", "--system", "pip"],
            stdout = subprocess.PIPE,
            stderr = subprocess.STDOUT,
        )
        if probe_sys.returncode != 0:
            return False  # uv is broken, fall back to pip
        UV_NEEDS_SYSTEM = True
    return True


def _filter_requirements(req: Path, skip: set[str]) -> Path:
    """Return a temp copy of a requirements file with certain packages removed."""
    lines = req.read_text(encoding = "utf-8").splitlines(keepends = True)
    filtered = [
        line
        for line in lines
        if not any(line.strip().lower().startswith(pkg) for pkg in skip)
    ]
    tmp = tempfile.NamedTemporaryFile(
        mode = "w",
        suffix = ".txt",
        delete = False,
        encoding = "utf-8",
    )
    tmp.writelines(filtered)
    tmp.close()
    return Path(tmp.name)


def _translate_pip_args_for_uv(args: tuple[str, ...]) -> list[str]:
    """Translate pip flags to their uv equivalents."""
    translated: list[str] = []
    for arg in args:
        if arg == "--no-cache-dir":
            continue  # uv cache is fast; drop this flag
        elif arg == "--force-reinstall":
            translated.append("--reinstall")
        else:
            translated.append(arg)
    return translated


def _build_pip_cmd(args: tuple[str, ...]) -> list[str]:
    """Build a standard pip install command.

    Strips uv-only flags like --upgrade-package that pip doesn't understand.
    """
    cmd = [sys.executable, "-m", "pip", "install"]
    skip_next = False
    for arg in args:
        if skip_next:
            skip_next = False
            continue
        if arg == "--upgrade-package":
            skip_next = True  # skip the flag and its value
            continue
        cmd.append(arg)
    return cmd


def _build_uv_cmd(args: tuple[str, ...]) -> list[str]:
    """Build a uv pip install command with translated flags."""
    cmd = ["uv", "pip", "install"]
    if UV_NEEDS_SYSTEM:
        cmd.append("--system")
    # Always pass --python so uv targets the correct environment.
    # Without this, uv can ignore an activated venv and install into
    # the system Python (observed on Colab and similar environments).
    cmd.extend(["--python", sys.executable])
    cmd.extend(_translate_pip_args_for_uv(args))
    # Torch is pre-installed by install.sh/setup.ps1.  Do not add
    # --torch-backend by default -- it can cause solver dead-ends on
    # CPU-only machines.  Callers that need it can set UV_TORCH_BACKEND.
    _tb = os.environ.get("UV_TORCH_BACKEND", "")
    if _tb:
        cmd.append(f"--torch-backend={_tb}")
    return cmd


def pip_install(
    label: str,
    *args: str,
    req: Path | None = None,
    constrain: bool = True,
) -> None:
    """Build and run a pip install command (uses uv when available, falls back to pip)."""
    constraint_args: list[str] = []
    if constrain and CONSTRAINTS.is_file():
        constraint_args = ["-c", str(CONSTRAINTS)]

    actual_req = req
    if req is not None and IS_WINDOWS and WINDOWS_SKIP_PACKAGES:
        actual_req = _filter_requirements(req, WINDOWS_SKIP_PACKAGES)
    req_args: list[str] = []
    if actual_req is not None:
        req_args = ["-r", str(actual_req)]

    try:
        if USE_UV:
            uv_cmd = _build_uv_cmd(args) + constraint_args + req_args
            if VERBOSE:
                print(f"   {label}...")
            result = subprocess.run(
                uv_cmd,
                stdout = subprocess.PIPE,
                stderr = subprocess.STDOUT,
            )
            if result.returncode == 0:
                return
            print(_red(f"   uv failed, falling back to pip..."))
            if result.stdout:
                print(result.stdout.decode(errors = "replace"))

        pip_cmd = _build_pip_cmd(args) + constraint_args + req_args
        run(f"{label} (pip)" if USE_UV else label, pip_cmd)
    finally:
        if actual_req is not None and actual_req != req:
            actual_req.unlink(missing_ok = True)


def download_file(url: str, dest: Path) -> None:
    """Download a file using urllib (no curl dependency)."""
    urllib.request.urlretrieve(url, dest)


def patch_package_file(package_name: str, relative_path: str, url: str) -> None:
    """Download a file from url and overwrite a file inside an installed package."""
    result = subprocess.run(
        [sys.executable, "-m", "pip", "show", package_name],
        capture_output = True,
        text = True,
    )
    if result.returncode != 0:
        _safe_print(
            _red(f"   ⚠️  Could not find package {package_name}, skipping patch")
        )
        return

    location = None
    for line in result.stdout.splitlines():
        if line.lower().startswith("location:"):
            location = line.split(":", 1)[1].strip()
            break

    if not location:
        _safe_print(_red(f"   ⚠️  Could not determine location of {package_name}"))
        return

    dest = Path(location) / relative_path
    print(_cyan(f"   Patching {dest.name} in {package_name}..."))
    download_file(url, dest)


# -- Main install sequence ---------------------------------------------


def install_python_stack() -> int:
    global USE_UV, _STEP, _TOTAL
    _STEP = 0

    # When called from install.sh (which already installed unsloth into the venv),
    # SKIP_STUDIO_BASE=1 is set to avoid redundant reinstallation of base packages.
    # When called from "unsloth studio update", it is NOT set so base packages
    # (unsloth + unsloth-zoo) are always reinstalled to pick up new versions.
    skip_base = os.environ.get("SKIP_STUDIO_BASE", "0") == "1"
    # When --package is used, install a different package name (e.g. roland-sloth for testing)
    package_name = os.environ.get("STUDIO_PACKAGE_NAME", "unsloth")
    # When --local is used, overlay a local repo checkout after updating deps
    local_repo = os.environ.get("STUDIO_LOCAL_REPO", "")
    base_total = 10 if IS_WINDOWS else 11
    _TOTAL = (base_total - 1) if skip_base else base_total

    # 1. Try to use uv for faster installs (must happen before pip upgrade
    #    because uv venvs don't include pip by default)
    USE_UV = _bootstrap_uv()

    # 2. Ensure pip is available (uv venvs created by install.sh don't include pip)
    _progress("pip bootstrap")
    if USE_UV:
        run(
            "Bootstrapping pip via uv",
            [
                "uv",
                "pip",
                "install",
                "--python",
                sys.executable,
                "pip",
            ],
        )
    else:
        # pip may not exist yet (uv-created venvs omit it). Try ensurepip
        # first, then upgrade. Only fall back to a direct upgrade when pip
        # is already present.
        _has_pip = (
            subprocess.run(
                [sys.executable, "-m", "pip", "--version"],
                stdout = subprocess.DEVNULL,
                stderr = subprocess.DEVNULL,
            ).returncode
            == 0
        )

        if not _has_pip:
            run(
                "Bootstrapping pip via ensurepip",
                [sys.executable, "-m", "ensurepip", "--upgrade"],
            )
        else:
            run(
                "Upgrading pip",
                [sys.executable, "-m", "pip", "install", "--upgrade", "pip"],
            )

    # 3. Core packages: unsloth-zoo + unsloth (or custom package name)
    if skip_base:
        print(_green(f"✅ {package_name} already installed — skipping base packages"))
    elif local_repo:
        # Local dev install: update deps from base.txt, then overlay the
        # local checkout as an editable install (--no-deps so torch is
        # never re-resolved).
        _progress("base packages")
        pip_install(
            "Updating base packages",
            "--no-cache-dir",
            "--upgrade-package",
            "unsloth",
            "--upgrade-package",
            "unsloth-zoo",
            req = REQ_ROOT / "base.txt",
        )
        pip_install(
            "Overlaying local repo (editable)",
            "--no-cache-dir",
            "--no-deps",
            "-e",
            local_repo,
            constrain = False,
        )
    elif package_name != "unsloth":
        # Custom package name (e.g. roland-sloth for testing) — install directly
        _progress("base packages")
        pip_install(
            f"Installing {package_name}",
            "--no-cache-dir",
            package_name,
        )
    else:
        # Update path: upgrade only unsloth + unsloth-zoo while preserving
        # existing torch/CUDA installations.  Torch is pre-installed by
        # install.sh / setup.ps1; --upgrade-package targets only base pkgs.
        _progress("base packages")
        pip_install(
            "Updating base packages",
            "--no-cache-dir",
            "--upgrade-package",
            "unsloth",
            "--upgrade-package",
            "unsloth-zoo",
            req = REQ_ROOT / "base.txt",
        )

    # 3. Extra dependencies
    _progress("unsloth extras")
    pip_install(
        "Installing additional unsloth dependencies",
        "--no-cache-dir",
        req = REQ_ROOT / "extras.txt",
    )

    # 3b. Extra dependencies (no-deps) -- audio model support etc.
    _progress("extra codecs")
    pip_install(
        "Installing extras (no-deps)",
        "--no-deps",
        "--no-cache-dir",
        req = REQ_ROOT / "extras-no-deps.txt",
    )

    # 4. Overrides (torchao, transformers) -- force-reinstall
    _progress("dependency overrides")
    pip_install(
        "Installing dependency overrides",
        "--force-reinstall",
        "--no-cache-dir",
        req = REQ_ROOT / "overrides.txt",
    )

    # 5. Triton kernels (no-deps, from source)
    if not IS_WINDOWS:
        _progress("triton kernels")
        pip_install(
            "Installing triton kernels",
            "--no-deps",
            "--no-cache-dir",
            req = REQ_ROOT / "triton-kernels.txt",
            constrain = False,
        )

    # # 6. Patch: override llama_cpp.py with fix from unsloth-zoo  feature/llama-cpp-windows-support branch
    # patch_package_file(
    #     "unsloth-zoo",
    #     os.path.join("unsloth_zoo", "llama_cpp.py"),
    #     "https://raw.githubusercontent.com/unslothai/unsloth-zoo/refs/heads/main/unsloth_zoo/llama_cpp.py",
    # )

    # # 7a. Patch: override vision.py with fix from unsloth PR #4091
    # patch_package_file(
    #     "unsloth",
    #     os.path.join("unsloth", "models", "vision.py"),
    #     "https://raw.githubusercontent.com/unslothai/unsloth/80e0108a684c882965a02a8ed851e3473c1145ab/unsloth/models/vision.py",
    # )

    # # 7b. Patch : override save.py with fix from feature/llama-cpp-windows-support
    # patch_package_file(
    #     "unsloth",
    #     os.path.join("unsloth", "save.py"),
    #     "https://raw.githubusercontent.com/unslothai/unsloth/refs/heads/main/unsloth/save.py",
    # )

    # 8. Studio dependencies
    _progress("studio deps")
    pip_install(
        "Installing studio dependencies",
        "--no-cache-dir",
        req = REQ_ROOT / "studio.txt",
    )

    # 9. Data-designer dependencies
    _progress("data designer deps")
    pip_install(
        "Installing data-designer base dependencies",
        "--no-cache-dir",
        req = SINGLE_ENV / "data-designer-deps.txt",
    )

    # 10. Data-designer packages (no-deps to avoid conflicts)
    _progress("data designer")
    pip_install(
        "Installing data-designer",
        "--no-cache-dir",
        "--no-deps",
        req = SINGLE_ENV / "data-designer.txt",
    )

    # 11. Local Data Designer seed plugin
    if not LOCAL_DD_UNSTRUCTURED_PLUGIN.is_dir():
        _safe_print(
            _red(
                f"❌ Missing local plugin directory: {LOCAL_DD_UNSTRUCTURED_PLUGIN}",
            ),
        )
        return 1
    _progress("local plugin")
    pip_install(
        "Installing local data-designer unstructured plugin",
        "--no-cache-dir",
        "--no-deps",
        str(LOCAL_DD_UNSTRUCTURED_PLUGIN),
        constrain = False,
    )

    # 12. Patch metadata for single-env compatibility
    _progress("finalizing")
    run(
        "Patching single-env metadata",
        [sys.executable, str(SINGLE_ENV / "patch_metadata.py")],
    )

    # 13. Final check (silent; third-party conflicts are expected)
    subprocess.run(
        [sys.executable, "-m", "pip", "check"],
        stdout = subprocess.DEVNULL,
        stderr = subprocess.DEVNULL,
    )

    _safe_print(_green("✅ Python dependencies installed"))
    return 0


if __name__ == "__main__":
    sys.exit(install_python_stack())