use std::path::PathBuf;

use clap::{Args, Subcommand};

// each variant carries its own arguments as a struct rather than as fields
// spread across the enum. the command that implements it takes that struct, so
// main does not unpack what clap has already parsed and hand it on as a row of
// booleans nothing but position tells apart
#[derive(Subcommand, Debug)]
pub enum Link {
    /// Move untracked paths into the store and symlink them back
    Add(Add),

    /// Move paths in the store back into the repository
    Restore(Restore),

    /// List what this repository keeps in the store
    List(List),

    /// List untracked paths a sandbox would still see
    Check(Check),

    /// Move this checkout's paths from the old store layout into its own directory
    Migrate(Migrate),
}

#[derive(Args, Debug)]
pub struct Migrate {
    #[command(flatten)]
    pub store: Store,
}

#[derive(Args, Debug)]
pub struct Add {
    /// Untracked or ignored paths inside the repository
    #[arg(required = true)]
    pub paths: Vec<PathBuf>,

    /// Link to a store path that already exists
    #[arg(long)]
    pub force: bool,

    #[command(flatten)]
    pub store: Store,
}

#[derive(Args, Debug)]
pub struct Restore {
    // said here rather than checked at runtime, so a mistake in the
    // arguments is reported as one, with the usage and the exit code clap
    // gives every other argument error
    #[arg(required_unless_present = "all", conflicts_with = "all")]
    pub paths: Vec<PathBuf>,

    /// Restore every path this repository has in the store
    #[arg(long)]
    pub all: bool,

    #[command(flatten)]
    pub store: Store,
}

#[derive(Args, Debug)]
pub struct List {
    #[command(flatten)]
    pub store: Store,
}

#[derive(Args, Debug)]
pub struct Check {
    /// Limit the listing to these paths
    pub paths: Vec<PathBuf>,

    /// Print `<code> <path>` for scripts, as `git status --porcelain` does
    #[arg(long)]
    pub porcelain: bool,

    /// Exit with 4 when anything is outside the store, for scripts
    #[arg(long)]
    pub exit_code: bool,

    /// Terminate porcelain entries with NUL
    #[arg(short = 'z')]
    pub null: bool,

    #[command(flatten)]
    pub store: Store,
}

#[derive(Args, Debug)]
pub struct Store {
    /// Where the out-of-repo store lives
    ///
    /// Defaults to `${XDG_DATA_HOME:-$HOME/.local/share}/ahab`.
    #[arg(long = "store", env = "AHAB_LINK_ROOT", value_name = "DIR")]
    pub root: Option<PathBuf>,
}

impl Store {
    pub fn root(&self) -> Option<&std::path::Path> {
        self.root.as_deref()
    }
}