"""Sync workspace symlinks from zshrc environment variables."""

import os
import subprocess
from pathlib import Path

from rich.console import Console

from bin.project_root import get_myclaude_project_root, get_workspace_root

console = Console()
stderr_console = Console(stderr=True)

# Link name -> list of environment variable names to try, in order.
_LINK_MAP: dict[str, list[str]] = {
    "myacademia": ["path_myacademia"],
    "myslides": ["path_myslides", "MYSLIDES_ROOT"],
    "metabot": ["METABOT_HOME"],
    "mytoolkit": ["path_mytoolkit", "MYTOOLKIT_ROOT"],
    "mywebpage": ["path_mywebpage", "MYWEBPAGE_ROOT"],
}


def _read_zsh_env(var: str, zshrc: Path) -> str | None:
    """Source zshrc and print the value of a variable."""
    cmd = [
        "zsh",
        "-c",
        f"source '{zshrc}' >/dev/null 2>&1; echo -n ${var}",
    ]
    try:
        result = subprocess.run(
            cmd,
            capture_output=True,
            text=True,
            check=False,
            timeout=10,
        )
    except (OSError, subprocess.TimeoutExpired):
        return None
    value = result.stdout.strip()
    return value if value else None


def _resolve_target(
    env_vars: list[str],
    zshrc: Path,
) -> Path | None:
    """Find the first valid target path from environment variables."""
    for var in env_vars:
        raw = _read_zsh_env(var, zshrc)
        if raw is None:
            continue
        expanded = os.path.expandvars(os.path.expanduser(raw))
        path = Path(expanded)
        if path.exists():
            return path.resolve()
    return None


def _current_link_target(workspace: Path, name: str) -> Path | None:
    """Return the target of an existing symlink, or None."""
    link = workspace / name
    if link.is_symlink():
        try:
            return Path(os.readlink(link))
        except OSError:
            return None
    return None


def _sync_link(
    workspace: Path,
    name: str,
    target: Path,
    dry_run: bool,
    force: bool,
) -> bool:
    """Create or update a symlink. Returns True if changed."""
    link = workspace / name
    current = _current_link_target(workspace, name)

    if current is not None and current.resolve() == target.resolve():
        return False

    if link.exists() and not link.is_symlink():
        if not force:
            stderr_console.print(
                f"[yellow]{name} exists but is not a symlink. "
                "Use --force to replace.[/yellow]"
            )
            return False
        if dry_run:
            console.print(
                f"[dry-run] Would remove {name} and symlink -> {target}"
            )
            return True
        if link.is_dir():
            link.rmdir()
        else:
            link.unlink()
    elif current is not None:
        if dry_run:
            console.print(
                f"[dry-run] Would update {name}: {current} -> {target}"
            )
            return True
        link.unlink()
    else:
        if dry_run:
            console.print(f"[dry-run] Would create {name} -> {target}")
            return True

    link.symlink_to(target, target_is_directory=target.is_dir())
    return True


def sync_workspace_links(
    zshrc: Path | None = None,
    dry_run: bool = False,
    force: bool = False,
    verbose: bool = True,
) -> bool:
    """Sync all workspace symlinks. Returns True on success."""
    workspace = get_workspace_root()
    if zshrc is None:
        zshrc = Path.home() / ".zshrc"

    if verbose:
        console.print(f"[bold]Workspace:[/bold] {workspace}")
        console.print(f"[bold]Zshrc:[/bold]     {zshrc}")
        console.print()

    changed = 0
    skipped = 0
    broken = 0

    # Handle myclaude separately: use project root detection, not zshrc.
    myclaude_target = get_myclaude_project_root()
    if _sync_link(workspace, "myclaude", myclaude_target, dry_run, force):
        action = "would update" if dry_run else "updated"
        if verbose:
            console.print(
                f"[green]myclaude: {action} -> {myclaude_target}[/green]"
            )
        changed += 1
    else:
        if verbose:
            console.print("[dim]myclaude: already correct[/dim]")

    for name, env_vars in _LINK_MAP.items():
        target = _resolve_target(env_vars, zshrc)
        if target is None:
            link = workspace / name
            if link.is_symlink() and not link.exists():
                if verbose:
                    stderr_console.print(
                        f"[red]{name}: broken symlink (no env var found)[/red]"
                    )
                broken += 1
            else:
                if verbose:
                    console.print(f"[dim]{name}: skipped (no env var)[/dim]")
                skipped += 1
            continue

        if _sync_link(workspace, name, target, dry_run, force):
            action = "would update" if dry_run else "updated"
            if verbose:
                console.print(f"[green]{name}: {action} -> {target}[/green]")
            changed += 1
        else:
            if verbose:
                console.print(f"[dim]{name}: already correct[/dim]")

    if verbose:
        console.print()
        label = "Preview" if dry_run else "Done"
        console.print(
            f"[bold]{label}:[/bold] {changed} changed, "
            f"{skipped} skipped, {broken} broken."
        )

    return broken == 0