"""
install_dependencies.py
========================
Installs all Python dependencies for the PST Email Extractor and
verifies that pypff (libpff) is importable.

Run once before first use:
    python install_dependencies.py

Platform notes
--------------
* Linux / macOS  – pypff is usually available via pip (libpff-python) or a
                   system package manager.
* Windows        – pypff typically requires a pre-built wheel or compiling
                   libpff from source.  See the README for details.
"""

import os
import sys
import subprocess
import platform
from importlib.util import find_spec

# ── package lists ────────────────────────────────────────────────
# Packages that install cleanly via pip on all platforms
PIP_PACKAGES: list[tuple[str, str]] = [
    ("tqdm", "tqdm>=4.66"),            # Progress bars
]

# pypff can be installed with 'libpff-python' on Linux/macOS
PYPFF_PIP_NAME = "libpff-python"


# ── helpers ──────────────────────────────────────────────────────

def run(cmd: list[str]) -> subprocess.CompletedProcess:
    """Print and run a command, returning the result without raising."""
    print(f"\n>> {' '.join(cmd)}")
    return subprocess.run(cmd, check=False)


def is_importable(module: str) -> bool:
    """Return True if *module* can be found in the current environment."""
    return find_spec(module) is not None


# ── steps ────────────────────────────────────────────────────────

def ensure_pip() -> None:
    """Bootstrap / upgrade pip, setuptools, and wheel."""
    print("\n[1/3] Ensuring pip is up-to-date …")
    run([sys.executable, "-m", "ensurepip", "--upgrade"])
    run([sys.executable, "-m", "pip", "install", "--upgrade",
         "pip", "setuptools", "wheel"])


def install_pip_packages() -> None:
    """Install the pip-only dependencies."""
    print("\n[2/3] Installing pip packages …")
    specs = [spec for _, spec in PIP_PACKAGES]
    result = run([sys.executable, "-m", "pip", "install", "--upgrade"] + specs)
    if result.returncode != 0:
        print("\n❌  ERROR: Failed to install pip packages.")
        sys.exit(result.returncode)

    # Verify each import
    for module, spec in PIP_PACKAGES:
        ok = is_importable(module)
        status = "✓" if ok else "✗"
        print(f"  {status}  {spec} ({'ok' if ok else 'MISSING'})")


def install_pypff() -> bool:
    """
    Try to install pypff via pip (works on Linux/macOS).
    On Windows this usually fails; we give targeted guidance instead.
    """
    print("\n[3/3] Installing pypff (libpff-python) …")

    if is_importable("pypff"):
        print("  ✓  pypff is already importable – skipping install.")
        return True

    result = run([sys.executable, "-m", "pip", "install", "--upgrade", PYPFF_PIP_NAME])

    if result.returncode == 0 and is_importable("pypff"):
        print("  ✓  pypff installed and importable.")
        return True

    # ── second attempt: some distros ship it as 'pypff' directly ──
    result2 = run([sys.executable, "-m", "pip", "install", "--upgrade", "pypff"])
    if result2.returncode == 0 and is_importable("pypff"):
        print("  ✓  pypff installed via 'pypff' package name.")
        return True

    print("  ✗  Could not install pypff automatically.")
    return False


# ── platform guidance ─────────────────────────────────────────────

def print_pypff_guidance() -> None:
    system = platform.system()
    py_ver = f"{sys.version_info.major}.{sys.version_info.minor}"

    print("\n" + "=" * 72)
    print("MANUAL INSTALLATION REQUIRED: pypff / libpff")
    print("=" * 72)

    if system == "Linux":
        print(
            "On Debian / Ubuntu:\n"
            "  sudo apt-get install python3-libpff\n"
            "  # or\n"
            "  pip install libpff-python\n\n"
            "On Fedora / RHEL:\n"
            "  sudo dnf install libpff-devel python3-libpff\n"
        )
    elif system == "Darwin":
        print(
            "On macOS (Homebrew):\n"
            "  brew install libpff\n"
            "  pip install libpff-python\n"
        )
    elif system == "Windows":
        print(
            f"On Windows (Python {py_ver}):\n"
            "  Option 1 – Pre-built wheel (if available for your Python version):\n"
            "    pip install libpff-python\n\n"
            "  Option 2 – Build from source:\n"
            "    https://github.com/libyal/libpff/blob/main/documentation/Building.md\n\n"
            "  Option 3 – Use WSL (Windows Subsystem for Linux) and follow the Linux steps.\n"
        )
    else:
        print(
            "  Please visit https://github.com/libyal/libpff for build instructions\n"
            f"  appropriate for your platform ({system}).\n"
        )

    print("=" * 72)


# ── main ──────────────────────────────────────────────────────────

def main() -> None:
    print("PST Email Extractor – Dependency Installer")
    print("=" * 72)
    print(f"  Python:     {sys.version.replace(chr(10), ' ')}")
    print(f"  Executable: {sys.executable}")
    print(f"  Platform:   {platform.platform()}")
    print(f"  CWD:        {os.getcwd()}")

    ensure_pip()
    install_pip_packages()
    has_pypff = install_pypff()

    # ── summary ──────────────────────────────────────────────────
    print("\n" + "=" * 72)
    print("Installation summary")
    print("=" * 72)
    for module, spec in PIP_PACKAGES:
        ok = is_importable(module)
        print(f"  {'✓' if ok else '✗'}  {spec}")
    print(f"  {'✓' if has_pypff else '✗'}  pypff (libpff)")
    print("=" * 72)

    if not has_pypff:
        print_pypff_guidance()
        sys.exit(2)

    print("\n✅  All dependencies are installed.")
    print("   You can now run:  python Extract.py [directory]")


if __name__ == "__main__":
    main()