//! Command-line definitions and dispatch.

mod auth;
mod format;
mod identity;
mod json;
mod proposal;
mod receipt;
mod sync;
pub mod ui;
mod workspace;

use anyhow::{Context, Result};
use clap::{Parser, Subcommand};
use oxy_core::repo::Repo;
use std::path::PathBuf;

#[derive(Parser)]
#[command(
    name = "oxy",
    version,
    about = "Oxygen: breathing fresh air into version control"
)]
struct Cli {
    /// Plain output: no colour, no spinner (also implied by NO_COLOR or a non-terminal)
    #[arg(long, global = true)]
    plain: bool,
    /// Read the repository as it was after operation OP (an ID from oxy op log, @ or @-); commands that would change it are refused
    #[arg(long, global = true, value_name = "OP")]
    at_op: Option<String>,
    #[command(subcommand)]
    cmd: Cmd,
}

/// `--at-op`, for `open` to apply.
static AT_OP: std::sync::OnceLock<Option<String>> = std::sync::OnceLock::new();

#[derive(Subcommand)]
enum Cmd {
    /// Create a repository in PATH (default: current directory)
    Init {
        /// Directory to create the repository in (default: the current directory)
        path: Option<PathBuf>,
        /// No working copy: an object store and references only, for hosting
        #[arg(long)]
        bare: bool,
    },
    /// Clone a repository from a local path or an http(s) URL
    Clone {
        /// Local path or http(s) URL of the repository
        url: String,
        /// Directory to clone into (default: the last part of the URL)
        dest: Option<PathBuf>,
        /// Leave blobs larger than this (e.g. 1M) to be fetched on first read
        #[arg(long)]
        max_blob: Option<String>,
        /// Materialize only these paths (repeatable); implies lazy blobs
        #[arg(long = "sparse")]
        sparse: Vec<String>,
        /// Shallow clone: fetch only this many levels of history below the heads
        #[arg(long)]
        depth: Option<u32>,
        /// Clone the subrepos too (as oxy submodule update --init)
        #[arg(long)]
        recursive: bool,
    },
    /// Fetch more history below a shallow clone's boundary
    Deepen {
        /// Levels of history to add below the boundary
        #[arg(default_value_t = 10)]
        depth: u32,
        /// Remote to fetch the history from
        #[arg(long, default_value = "origin")]
        remote: String,
    },
    /// Show or set the sparse filter (paths to materialize); re-checks out the bookmark
    Sparse {
        /// Paths to materialize; none prints the current filter
        paths: Vec<String>,
    },
    /// Show the working copy: changed paths and conflicts
    Status {
        /// Machine-readable output: paths, and every conflict with its kind and contributing changes
        #[arg(long)]
        json: bool,
    },
    /// One-line summary for shell prompts; fast and records nothing
    Prompt {
        /// Placeholders: %b bookmark, %c change id, %h heads, %d dirty (*), %x conflict (!), %A/%D ahead/behind (+n/-n), %a/%B raw counts, %s state glyph, %U/%O ahead/behind arrows, %i icon
        #[arg(long, default_value = oxy_core::repo::DEFAULT_PROMPT_FORMAT)]
        format: String,
        /// Glyph format (%i %b %c %s%U%O) instead of the plain default
        #[arg(long)]
        glyphs: bool,
        /// Colour by state (cyan clean, yellow dirty, red conflicted): raw escapes, or guarded for a bash or zsh PS1
        #[arg(long, value_parser = ["raw", "bash", "zsh"])]
        color: Option<String>,
    },
    /// Record the working copy as a change on the current bookmark
    Commit {
        /// The change's message: a subject line, then optionally a blank line and a body
        #[arg(short, long, required_unless_present = "file", conflicts_with = "file")]
        message: Option<String>,
        /// Read the message from FILE (`-` for standard input)
        #[arg(short = 'F', long, value_name = "FILE")]
        file: Option<PathBuf>,
        /// Extra explicit dependencies (ChangeId prefix, #hash prefix)
        #[arg(long = "depends-on")]
        depends_on: Vec<String>,
        /// Commit only these paths; the rest stays as uncommitted work
        paths: Vec<String>,
        /// Choose hunks one by one
        #[arg(short, long)]
        interactive: bool,
        /// Commit these hunks (as `oxy hunks` numbers them), comma separated
        #[arg(long, value_delimiter = ',')]
        hunks: Vec<usize>,
    },
    /// Fold CHANGE into one of its dependencies (keeps that change's id)
    Squash {
        /// The change to fold (ChangeId prefix, #hash prefix)
        change: String,
        /// The dependency that absorbs it
        #[arg(long)]
        into: String,
    },
    /// Re-express CHANGE against another base state
    Rebase {
        /// The change to re-express (ChangeId prefix, #hash prefix)
        change: String,
        /// The changes, bookmark or tag whose state becomes the new base
        #[arg(long, required = true, num_args = 1..)]
        onto: Vec<String>,
        /// Where the rebase would be conflicted, merge the target into the
        /// current bookmark instead, leaving the conflict in the working
        /// copy to fix and commit
        #[arg(long)]
        into_working_copy: bool,
    },
    /// Show which change introduced each line of a file
    Blame {
        /// File to annotate, relative to the repository root
        path: String,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Find the change that introduced a regression
    Bisect {
        #[command(subcommand)]
        cmd: BisectCmd,
    },
    /// List changes reachable from the bookmark and the working copy
    Log {
        /// Show at most this many changes
        #[arg(short = 'n', long)]
        limit: Option<usize>,
        /// Show full messages, dependencies, and signatures
        #[arg(short, long)]
        verbose: bool,
        /// Only changes touching this path (renames followed)
        #[arg(long)]
        path: Option<String>,
        /// Only changes that wrote or deleted lines START to END of PATH
        /// (numbered as in the working copy's base), or deleted lines from
        /// between them: the history of a function
        #[arg(short = 'L', value_name = "START,END:PATH", conflicts_with = "path")]
        lines: Option<String>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Show what the working copy changes against its base
    Diff {
        /// A change instead of the working copy
        change: Option<String>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Print a file as it is in a state (default: the working copy's base)
    Cat {
        /// File to print, relative to the repository root
        path: String,
        /// A change, bookmark, or tag
        #[arg(short = 'r', long)]
        change: Option<String>,
    },
    /// Print the repository root, workspace, and bookmark
    Root {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Print the version of oxy, its repository format, and protocol
    Version {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Restore paths to the working copy's base, or undo chosen hunks
    Discard {
        /// Paths to restore; none with --hunks, or everything with neither
        paths: Vec<String>,
        /// Hunk indices as `oxy hunks` numbers them, comma separated
        #[arg(long, value_delimiter = ',')]
        hunks: Vec<usize>,
    },
    /// List the working copy's hunks, numbered as commit --hunks expects
    Hunks {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// With -m, change the message of a head; without, name the working
    /// copy for a build: its tag, or the nearest tag plus distance and
    /// change, or the bookmark and change, and -dirty
    Describe {
        /// The new message
        #[arg(short, long)]
        message: Option<String>,
        /// The head to describe (default: the one the working copy sits on)
        change: Option<String>,
        /// Machine-readable output (naming only)
        #[arg(long, conflicts_with = "message")]
        json: bool,
    },
    /// Fold the working copy into the head it sits on, or into CHANGE with --into
    Amend {
        /// Replace the message too
        #[arg(short, long)]
        message: Option<String>,
        /// Amend an older change; the edits must touch only lines it already knows
        #[arg(long)]
        into: Option<String>,
    },
    /// Split a head: the named paths become a separate first change
    Split {
        /// The head to split
        change: String,
        /// Paths whose edits become the first change
        paths: Vec<String>,
    },
    /// Drop a head from the bookmark; its content stays on disk as uncommitted work
    Abandon {
        /// The head to drop (ChangeId prefix, #hash prefix)
        change: String,
    },
    /// Show one change (ChangeId prefix, #hash prefix, or @)
    Show {
        /// ChangeId prefix, #hash prefix, or @ for the working copy
        change: String,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Move the working copy to the state formed by CHANGE... (default: the bookmark heads)
    Checkout {
        /// Changes whose state to check out (default: the bookmark heads)
        changes: Vec<String>,
        /// Throw away uncommitted working-copy changes
        #[arg(long)]
        discard: bool,
        /// Take uncommitted changes along; refused when the target has
        /// other versions of the files they touch
        #[arg(long, conflicts_with = "discard")]
        carry: bool,
    },
    /// Report which conflicts of the working copy's base are resolved by the current files
    Resolve {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Undo the last operation
    Undo,
    /// Write a checkpoint of the current bookmark's state now
    Checkpoint,
    /// Print a shell completion script: `oxy completions bash > ~/.local/share/bash-completion/completions/oxy`
    Completions {
        /// bash, zsh, fish, elvish or powershell
        shell: clap_complete::Shell,
    },
    /// Write man pages (oxy.1 and one per command) into DIR, or print oxy.1
    Man {
        /// Directory to write every page into, e.g. ~/.local/share/man/man1
        #[arg(long)]
        dir: Option<PathBuf>,
    },
    /// Check the identity, configuration and remotes, and say what to do about any problem
    Doctor {
        /// Do not contact the remotes
        #[arg(long)]
        offline: bool,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Check the repository's integrity: objects, operation log, references, signatures, checkpoints
    Fsck {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Prune unreachable objects older than the grace period and repack everything into one pack
    Gc {
        /// Ignore the grace period (core.gc-grace) and prune immediately
        #[arg(long)]
        now: bool,
    },
    /// List operations
    #[command(name = "op")]
    Op {
        #[command(subcommand)]
        cmd: OpCmd,
    },
    /// Take the advisory local lock on a lockable file, making it writable
    Lock {
        /// The lockable file
        path: String,
    },
    /// Release the local lock and make the file read-only again
    Unlock {
        /// The locked file
        path: String,
    },
    /// Workspaces: extra checkout directories sharing this repository
    Workspace {
        #[command(subcommand)]
        cmd: WorkspaceCmd,
    },
    /// Bookmarks: named states; each workspace works on one
    Bookmark {
        #[command(subcommand)]
        cmd: BookmarkCmd,
    },
    /// Union another bookmark's heads into the current one (no merge change)
    Merge {
        /// The bookmark whose heads to add
        bookmark: String,
    },
    /// Sign in to a hub once, for every repository on it
    Auth {
        #[command(subcommand)]
        cmd: AuthCmd,
    },
    /// Subrepositories: nested repositories pinned to a state
    Submodule {
        #[command(subcommand)]
        cmd: SubmoduleCmd,
    },
    /// Execution receipts: signed records of what a runner ran on a state
    Receipt {
        #[command(subcommand)]
        cmd: ReceiptCmd,
    },
    /// Tags: immutable named states
    Tag {
        #[command(subcommand)]
        cmd: TagCmd,
    },
    /// Manage remotes
    Remote {
        #[command(subcommand)]
        cmd: RemoteCmd,
    },
    /// Fetch every bookmark of a remote into its tracking references
    Fetch {
        /// Remote name (default: origin)
        remote: Option<String>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Fetch, then union the remote bookmark into the local one (no merge change)
    Pull {
        /// Remote name (default: origin)
        remote: Option<String>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Push the current bookmark to a remote
    Push {
        /// Remote name (default: origin)
        remote: Option<String>,
        /// Allow dropping heads the remote has
        #[arg(long)]
        force: bool,
        /// Push this bookmark instead of the workspace's current one
        #[arg(short = 'b', long)]
        bookmark: Option<String>,
        /// Delete this bookmark on the remote (never its default bookmark);
        /// the local bookmark is kept
        #[arg(long, value_name = "NAME", conflicts_with_all = ["bookmark", "force"])]
        delete: Option<String>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Serve repositories under ROOT over HTTPS (with --tls-cert/--tls-key) or plain HTTP
    Serve {
        /// Directory with one repository per subdirectory
        #[arg(long, default_value = ".")]
        root: PathBuf,
        /// Address and port to listen on
        #[arg(long, default_value = "127.0.0.1:8890")]
        bind: String,
        /// Bearer token allowed to push (repeatable); none means open
        #[arg(long = "token")]
        tokens: Vec<String>,
        /// PEM certificate chain; enables HTTPS together with --tls-key
        #[arg(long, requires = "tls_key")]
        tls_cert: Option<PathBuf>,
        /// PEM private key
        #[arg(long, requires = "tls_cert")]
        tls_key: Option<PathBuf>,
    },
    /// Manage the signing identity
    Identity {
        #[command(subcommand)]
        cmd: IdentityCmd,
    },
    /// Seal changes with your key: named ones, or every change on the current bookmark you can authenticate but have not
    Seal {
        /// Changes to seal (default: every change on the bookmark you can authenticate and have not sealed)
        changes: Vec<String>,
        /// Seal every change of a hub proposal and push the seal (your approval)
        #[arg(long, conflicts_with = "changes")]
        proposal: Option<String>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Hub proposals: show one, or land it from this client
    Proposal {
        #[command(subcommand)]
        cmd: ProposalCmd,
    },
    /// Verify the signatures on a change (default: every change in the log)
    Verify {
        /// The change to verify (default: every change in the log)
        change: Option<String>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Git interoperability
    Git {
        #[command(subcommand)]
        cmd: GitCmd,
    },
    /// Manage the trust policy (who may update which bookmarks)
    Policy {
        #[command(subcommand)]
        cmd: PolicyCmd,
    },
    /// Set a configuration key (author.*, core.sign, core.op-retention, core.gc-grace, core.checkpoint-interval, filter.max-blob, filter.paths, workspace.bookmark, remote.<name>.url|token|ca, auth.helper with --user)
    Config {
        /// The key, such as author.name or remote.origin.token
        key: String,
        /// The value to set
        value: String,
        /// Write to the user file (~/.config/oxy/config.toml) instead of this repository
        #[arg(long)]
        user: bool,
    },
}

#[derive(Subcommand)]
enum OpCmd {
    /// List operations, newest first, with what each changed
    Log {
        /// Show only the latest N (snapshots folded together count as one)
        #[arg(short = 'n', long)]
        limit: Option<usize>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Go back to the bookmarks and working copy as they were after OP (recorded as a new operation, so it can be undone)
    Restore {
        /// The operation: an ID prefix from oxy op log, @ or @-
        op: String,
        /// Throw away uncommitted working-copy changes
        #[arg(long)]
        discard: bool,
    },
    /// Undo OP alone, keeping every operation after it: the bookmarks it moved go back
    Revert {
        /// The operation: an ID prefix from oxy op log
        op: String,
    },
}

#[derive(Subcommand)]
enum WorkspaceCmd {
    /// Create a workspace at PATH checked out on CHANGE... (default: the bookmark heads)
    Add {
        /// Directory for the new workspace (must be empty or absent)
        path: PathBuf,
        /// Changes whose state to check out there
        changes: Vec<String>,
    },
    /// List workspaces and their working-copy changes
    List {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Stop tracking a workspace (by id prefix or path); its files stay
    Forget {
        /// Workspace id prefix or path
        workspace: String,
    },
}

#[derive(Subcommand)]
enum BisectCmd {
    /// Begin; remembers where the working copy was
    Start,
    /// Mark CHANGE... (or the state under test) as good
    Good {
        /// Changes known to be good (default: the state under test)
        changes: Vec<String>,
    },
    /// Mark CHANGE... (or the state under test) as bad
    Bad {
        /// Changes known to be bad (default: the state under test)
        changes: Vec<String>,
    },
    /// The state under test cannot be tested; try another
    Skip,
    /// Run a command for each step: exit 0 good, 125 skip, else bad
    Run {
        /// Command and arguments to run at each step
        #[arg(required = true, trailing_var_arg = true)]
        command: Vec<String>,
    },
    /// Where the search stands
    Status {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Restore the working copy and forget the search
    Reset,
}

#[derive(Subcommand)]
enum BookmarkCmd {
    /// Create a bookmark at CHANGE... (default: the working copy's base)
    Create {
        /// Name of the new bookmark
        name: String,
        /// Its heads (default: the working copy's base). A state is its
        /// heads and what they depend on: a change alone may leave out
        /// earlier changes of the current state, which is refused unless
        /// --upto or --only says which is meant
        changes: Vec<String>,
        /// Everything of the current state up to CHANGE..., as a Git
        /// branch at a commit would hold
        #[arg(long, conflicts_with = "only")]
        upto: bool,
        /// Just CHANGE... and what they depend on
        #[arg(long)]
        only: bool,
    },
    /// Point an existing bookmark at CHANGE...
    Set {
        /// The bookmark to move
        name: String,
        /// Its new heads. A change alone may leave out changes the
        /// bookmark now holds that were recorded before it, which is
        /// refused unless --upto or --only says which is meant
        changes: Vec<String>,
        /// Everything the bookmark holds up to CHANGE..., as a Git branch
        /// moved to a commit would hold
        #[arg(long, conflicts_with = "only")]
        upto: bool,
        /// Just CHANGE... and what they depend on
        #[arg(long)]
        only: bool,
    },
    /// Remove a bookmark; its changes stay
    Delete {
        /// The bookmark to remove
        name: String,
    },
    /// List bookmarks with their heads and difference from origin
    List {
        /// Also list remotes' bookmarks that have no local bookmark
        #[arg(long, short)]
        all: bool,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Make NAME this workspace's bookmark and check it out. Uncommitted work stops it; --carry takes the work along, --discard drops it
    Switch {
        /// The bookmark to work on; one only a remote has (NAME or REMOTE/NAME) is created from it
        name: String,
        /// Throw away uncommitted working-copy changes
        #[arg(long)]
        discard: bool,
        /// Take uncommitted changes along; refused when NAME has other
        /// versions of the files they touch
        #[arg(long, conflicts_with = "discard")]
        carry: bool,
    },
}

#[derive(Subcommand)]
enum AuthCmd {
    /// Sign in to HUB in the browser (device sign-in) and keep the token for
    /// every repository there
    Login {
        /// The hub, as https://oxygenhub.io or oxygenhub.io (default: this checkout's origin)
        hub: Option<String>,
        /// Read a token from standard input instead (for CI and scripts)
        #[arg(long)]
        with_token: bool,
        /// PEM file of extra roots to trust (a hub with a self-signed certificate)
        #[arg(long)]
        ca: Option<PathBuf>,
    },
    /// List the hubs you are signed in to, checking each token with its hub
    Status,
    /// Forget HUB's token and revoke it on the hub
    Logout {
        /// The hub (default: this checkout's origin, or the only one)
        hub: Option<String>,
    },
}

#[derive(Subcommand)]
enum SubmoduleCmd {
    /// Clone URL (Oxygen or Git) into PATH and register it in .oxymodules
    Add {
        /// URL or path of the Oxygen or Git repository
        url: String,
        /// Where to put it, relative to the repository root
        path: String,
        /// Bookmark (Oxygen) or branch (Git) to check out and track
        #[arg(long)]
        bookmark: Option<String>,
    },
    /// Bring nested repositories to their pins
    Update {
        /// Clone nested repositories that are absent
        #[arg(long)]
        init: bool,
        /// Subrepos to update (default: all)
        paths: Vec<String>,
    },
    /// List subrepos with their pins and on-disk state
    Status {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Unregister PATH; the directory stays, the node goes with the next commit
    Remove {
        /// The subrepo to unregister
        path: String,
    },
}

#[derive(Subcommand)]
enum ReceiptCmd {
    /// The receipts kept for a state (default: the bookmark heads)
    List {
        /// Change, bookmark or tag whose state to look at
        rev: Option<String>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// One receipt in full, and whether its signature verifies
    Show {
        /// The receipt (a prefix of its hash, as `list` shows it)
        receipt: String,
        /// Change, bookmark or tag whose state holds it
        #[arg(long)]
        rev: Option<String>,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Write a signed receipt to FILE
    Export {
        /// The receipt (a prefix of its hash, as `list` shows it)
        receipt: String,
        /// Where to write it
        file: String,
        /// Change, bookmark or tag whose state holds it
        #[arg(long)]
        rev: Option<String>,
    },
    /// Check a signed receipt in FILE without keeping it
    Verify {
        /// A signed receipt, as a runner or `export` writes it
        file: String,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Verify a signed receipt in FILE and keep it with its state
    Import {
        /// A signed receipt, as a runner or `export` writes it
        file: String,
    },
}

#[derive(Subcommand)]
enum TagCmd {
    /// Tag the state of CHANGE... (default: the bookmark heads)
    Create {
        /// Name of the tag; tags never move
        name: String,
        /// Changes whose state to tag (default: the bookmark heads)
        changes: Vec<String>,
        /// A message recorded with the tag
        #[arg(short, long, default_value = "")]
        message: String,
    },
    /// List tags and the states they name
    List {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
}

#[derive(Subcommand)]
enum RemoteCmd {
    /// Add a remote
    Add {
        /// Name to refer to the remote by, such as origin
        name: String,
        /// Local path or http(s) URL of the repository
        url: String,
    },
    /// Remove a remote
    Remove {
        /// The remote to remove
        name: String,
    },
    /// List remotes and their URLs
    List {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
}

#[derive(Subcommand)]
enum ProposalCmd {
    /// Show a proposal by its hub URL
    Show {
        /// The proposal's URL on the hub
        url: String,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Fetch the proposal's changes, set the target bookmark to the projected state, and push with your key
    Land {
        /// The proposal's URL on the hub
        url: String,
        /// Land even when the hub reports blockers
        #[arg(long)]
        force: bool,
    },
}

#[derive(Subcommand)]
enum IdentityCmd {
    /// Generate a composite Ed25519 + ML-DSA-65 key pair and make it your author identity
    Create {
        /// Your name (default: author.name)
        #[arg(long)]
        name: Option<String>,
        /// Your email (default: author.email)
        #[arg(long)]
        email: Option<String>,
        /// Record the author in this repository only, not in the user config
        #[arg(long)]
        local: bool,
        /// Expire the identity this many days from now
        #[arg(long)]
        expires: Option<u64>,
    },
    /// Show the configured identity
    Show,
    /// Write your identity object to a file, to hand to a policy holder
    Export {
        /// File to write (default: <key>.identity in the current directory)
        path: Option<PathBuf>,
    },
    /// Sign a host's challenge (hex, at least 16 bytes) to prove you hold your key; prints the signature as hex
    SignChallenge {
        /// The host's challenge, as hex
        challenge: String,
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Move to a fresh key pair; the policy follows if it names your key
    Rotate,
    /// Re-issue your identity with a new expiry (in days from now; 0 = never)
    Renew {
        /// Days from now until it expires; 0 for never
        #[arg(long)]
        expires: u64,
    },
    /// Revoke a key: yours by default, or any key if you hold a policy root
    Revoke {
        /// KeyId prefix (default: your own key)
        key: Option<String>,
        /// Why, recorded in the revocation
        #[arg(long, default_value = "")]
        reason: String,
    },
    /// Keys allowed to sign or seal on your behalf
    Delegate {
        #[command(subcommand)]
        cmd: DelegateCmd,
    },
}

#[derive(Subcommand)]
enum DelegateCmd {
    /// Add a delegate from an exported identity file
    Add {
        /// The delegate's exported identity file
        identity_file: PathBuf,
    },
    /// Remove a delegate by KeyId prefix
    Remove {
        /// KeyId prefix of the delegate
        key: String,
    },
    /// List delegates
    List,
}

#[derive(Subcommand)]
enum GitCmd {
    /// Export the current bookmark to a Git repository (created bare if absent)
    Export {
        /// Git repository to write to (created bare if absent)
        git_dir: PathBuf,
        /// Git branch to write (default: the bookmark name)
        #[arg(long)]
        branch: Option<String>,
    },
    /// Fetch a branch from a Git remote (path or URL) into the current bookmark
    Fetch {
        /// Git remote: a path or URL
        url: String,
        /// Branch to fetch
        #[arg(long, default_value = "main")]
        branch: String,
    },
    /// Push the current bookmark to a branch of a Git remote (fetch first)
    Push {
        /// Git remote: a path or URL
        url: String,
        /// Branch to push to
        #[arg(long, default_value = "main")]
        branch: String,
    },
    /// Check this repository's import of a Git branch: every commit's tree must be reproduced exactly
    Verify {
        /// The Git repository the import came from
        git_dir: PathBuf,
        /// Branch that was imported
        #[arg(long, default_value = "main")]
        branch: String,
    },
    /// Import a Git branch into a new Oxygen repository at DEST
    Import {
        /// Git repository to read
        git_dir: PathBuf,
        /// Directory for the new Oxygen repository
        dest: PathBuf,
        /// Branch to import
        #[arg(long, default_value = "main")]
        branch: String,
    },
}

#[derive(Subcommand)]
enum PolicyCmd {
    /// Create the initial policy with your identity as the only root
    Init,
    /// Show the current policy
    Show {
        /// Machine-readable output: one JSON document on stdout
        #[arg(long)]
        json: bool,
    },
    /// Allow an identity (from `oxy identity export`) to update bookmarks
    Grant {
        /// The identity to grant, exported with `oxy identity export`
        identity_file: PathBuf,
        /// Reference pattern the grant applies to (default: every bookmark)
        #[arg(long)]
        pattern: Option<String>,
        /// Where to write the proposal when more root signatures are needed
        #[arg(long)]
        out: Option<PathBuf>,
    },
    /// Revoke a key (KeyId prefix of an identity in the policy)
    Revoke {
        /// KeyId prefix of the identity
        key: String,
        /// Where to write the proposal when more root signatures are needed
        #[arg(long)]
        out: Option<PathBuf>,
    },
    /// Manage root keys and the signature threshold for policy updates
    Root {
        #[command(subcommand)]
        cmd: RootCmd,
    },
    /// Add your root signature to a proposal file; applies it once the threshold is met
    Sign {
        /// The proposal file to sign
        proposal: PathBuf,
        /// Where to write the proposal if it still needs signatures (default: in place)
        #[arg(long)]
        out: Option<PathBuf>,
    },
}

#[derive(Subcommand)]
enum RootCmd {
    /// Make an exported identity a root key
    Add {
        /// The identity to make a root, exported with `oxy identity export`
        identity_file: PathBuf,
        /// Where to write the proposal when more root signatures are needed
        #[arg(long)]
        out: Option<PathBuf>,
    },
    /// Remove a root key by KeyId prefix
    Remove {
        /// KeyId prefix of the root key
        key: String,
        /// Where to write the proposal when more root signatures are needed
        #[arg(long)]
        out: Option<PathBuf>,
    },
    /// Require this many root signatures on policy updates
    Threshold {
        /// Number of root signatures
        n: u32,
        /// Where to write the proposal when more root signatures are needed
        #[arg(long)]
        out: Option<PathBuf>,
    },
}

/// Open the repository containing the current directory.
fn open() -> Result<Repo> {
    let repo = Repo::open(&std::env::current_dir()?).context("opening repository")?;
    match AT_OP.get().and_then(|o| o.as_deref()) {
        Some(op) => Ok(repo.at_op(op)?),
        None => Ok(repo),
    }
}

/// `oxy man`: every page into `dir`, or the top-level page on stdout.
fn man(dir: Option<PathBuf>) -> Result<i32> {
    use clap::CommandFactory;
    let cmd = Cli::command();
    match dir {
        Some(dir) => {
            std::fs::create_dir_all(&dir)?;
            clap_mangen::generate_to(cmd, &dir)?;
            let pages = std::fs::read_dir(&dir)?
                .filter(|e| {
                    e.as_ref()
                        .is_ok_and(|e| e.path().extension().is_some_and(|x| x == "1"))
                })
                .count();
            println!(
                "{}",
                ui::done(format!("Wrote {pages} man pages to {}", dir.display()))
            );
        }
        None => clap_mangen::Man::new(cmd).render(&mut std::io::stdout())?,
    }
    Ok(0)
}

/// Parse arguments and run; returns the process exit code.
pub fn run() -> Result<i32> {
    let cli = Cli::parse();
    ui::init(cli.plain);
    AT_OP.set(cli.at_op.clone()).ok();
    match cli.cmd {
        Cmd::Completions { shell } => {
            use clap::CommandFactory;
            clap_complete::generate(shell, &mut Cli::command(), "oxy", &mut std::io::stdout());
            Ok(0)
        }
        Cmd::Man { dir } => man(dir),
        Cmd::Init { path, bare } => workspace::init(path, bare),
        Cmd::Status { json } => workspace::status(json),
        Cmd::Prompt {
            format,
            glyphs,
            color,
        } => workspace::prompt(&format, glyphs, color.as_deref()),
        Cmd::Commit {
            message,
            file,
            depends_on,
            paths,
            interactive,
            hunks,
        } => {
            let message = match (message, file) {
                (Some(m), _) => m,
                (None, Some(f)) if f.as_os_str() == "-" => {
                    let mut s = String::new();
                    std::io::Read::read_to_string(&mut std::io::stdin(), &mut s)?;
                    s
                }
                (None, Some(f)) => std::fs::read_to_string(&f).map_err(|e| {
                    anyhow::anyhow!("reading the message from {}: {e}", f.display())
                })?,
                (None, None) => anyhow::bail!("a commit message is required (-m or -F)"),
            };
            workspace::commit(&message, &depends_on, &paths, interactive, &hunks)
        }
        Cmd::Cat { path, change } => workspace::cat(&path, change.as_deref()),
        Cmd::Root { json } => workspace::root(json),
        Cmd::Version { json } => workspace::version(json),
        Cmd::Discard { paths, hunks } => workspace::discard(&paths, &hunks),
        Cmd::Hunks { json } => workspace::hunks(json),
        Cmd::Squash { change, into } => workspace::squash(&change, &into),
        Cmd::Rebase {
            change,
            onto,
            into_working_copy,
        } => workspace::rebase(&change, &onto, into_working_copy),
        Cmd::Blame { path, json } => workspace::blame(&path, json),
        Cmd::Bisect { cmd } => match cmd {
            BisectCmd::Start => workspace::bisect_start(),
            BisectCmd::Good { changes } => workspace::bisect_mark(Some(true), &changes),
            BisectCmd::Bad { changes } => workspace::bisect_mark(Some(false), &changes),
            BisectCmd::Skip => workspace::bisect_mark(None, &[]),
            BisectCmd::Run { command } => workspace::bisect_run(&command),
            BisectCmd::Status { json } => workspace::bisect_status(json),
            BisectCmd::Reset => workspace::bisect_reset(),
        },
        Cmd::Log {
            limit,
            verbose,
            path,
            lines,
            json,
        } => workspace::log(limit, verbose, path.as_deref(), lines.as_deref(), json),
        Cmd::Diff { change, json } => workspace::diff(change.as_deref(), json),
        Cmd::Describe {
            message,
            change,
            json,
        } => match message {
            Some(m) => workspace::describe(&m, change.as_deref()),
            None if change.is_some() => {
                anyhow::bail!(
                    "naming works on the working copy; to change a head's message pass -m"
                )
            }
            None => workspace::describe_name(json),
        },
        Cmd::Amend { message, into } => workspace::amend(message.as_deref(), into.as_deref()),
        Cmd::Split { change, paths } => workspace::split(&change, &paths),
        Cmd::Abandon { change } => workspace::abandon(&change),
        Cmd::Show { change, json } => workspace::show(&change, json),
        Cmd::Checkout {
            changes,
            discard,
            carry,
        } => workspace::checkout(&changes, discard, carry),
        Cmd::Resolve { json } => workspace::resolve(json),
        Cmd::Undo => workspace::undo(),
        Cmd::Gc { now } => workspace::gc(now),
        Cmd::Fsck { json } => workspace::fsck(json),
        Cmd::Doctor { offline, json } => workspace::doctor(offline, json),
        Cmd::Checkpoint => workspace::checkpoint(),
        Cmd::Op { cmd } => match cmd {
            OpCmd::Log { limit, json } => workspace::op_log(limit, json),
            OpCmd::Restore { op, discard } => workspace::op_restore(&op, discard),
            OpCmd::Revert { op } => workspace::op_revert(&op),
        },
        Cmd::Clone {
            url,
            dest,
            max_blob,
            sparse,
            depth,
            recursive,
        } => sync::clone(&url, dest, max_blob.as_deref(), &sparse, depth, recursive),
        Cmd::Deepen { depth, remote } => sync::deepen(&remote, depth),
        Cmd::Sparse { paths } => workspace::sparse(&paths),
        Cmd::Lock { path } => workspace::lock(&path),
        Cmd::Unlock { path } => workspace::unlock(&path),
        Cmd::Workspace { cmd } => match cmd {
            WorkspaceCmd::Add { path, changes } => workspace::workspace_add(&path, &changes),
            WorkspaceCmd::List { json } => workspace::workspace_list(json),
            WorkspaceCmd::Forget { workspace } => workspace::workspace_forget(&workspace),
        },
        Cmd::Bookmark { cmd } => match cmd {
            BookmarkCmd::Create {
                name,
                changes,
                upto,
                only,
            } => workspace::bookmark_create(&name, &changes, upto, only),
            BookmarkCmd::Set {
                name,
                changes,
                upto,
                only,
            } => workspace::bookmark_set(&name, &changes, upto, only),
            BookmarkCmd::Delete { name } => workspace::bookmark_delete(&name),
            BookmarkCmd::List { all, json } => workspace::bookmark_list(all, json),
            BookmarkCmd::Switch {
                name,
                discard,
                carry,
            } => workspace::bookmark_switch(&name, discard, carry),
        },
        Cmd::Merge { bookmark } => workspace::merge(&bookmark),
        Cmd::Auth { cmd } => match cmd {
            AuthCmd::Login {
                hub,
                with_token,
                ca,
            } => auth::login(hub.as_deref(), with_token, ca),
            AuthCmd::Status => auth::status(),
            AuthCmd::Logout { hub } => auth::logout(hub.as_deref()),
        },
        Cmd::Submodule { cmd } => match cmd {
            SubmoduleCmd::Add {
                url,
                path,
                bookmark,
            } => sync::submodule_add(&url, &path, bookmark.as_deref()),
            SubmoduleCmd::Update { init, paths } => sync::submodule_update(init, &paths),
            SubmoduleCmd::Status { json } => sync::submodule_status(json),
            SubmoduleCmd::Remove { path } => sync::submodule_remove(&path),
        },
        Cmd::Receipt { cmd } => match cmd {
            ReceiptCmd::List { rev, json } => receipt::list(rev.as_deref(), json),
            ReceiptCmd::Show {
                receipt: r,
                rev,
                json,
            } => receipt::show(&r, rev.as_deref(), json),
            ReceiptCmd::Export {
                receipt: r,
                file,
                rev,
            } => receipt::export(&r, &file, rev.as_deref()),
            ReceiptCmd::Verify { file, json } => receipt::verify(&file, json),
            ReceiptCmd::Import { file } => receipt::import(&file),
        },
        Cmd::Tag { cmd } => match cmd {
            TagCmd::Create {
                name,
                changes,
                message,
            } => workspace::tag_create(&name, &changes, &message),
            TagCmd::List { json } => workspace::tag_list(json),
        },
        Cmd::Remote { cmd } => match cmd {
            RemoteCmd::Add { name, url } => sync::remote_add(&name, &url),
            RemoteCmd::Remove { name } => sync::remote_remove(&name),
            RemoteCmd::List { json } => sync::remote_list(json),
        },
        Cmd::Fetch { remote, json } => sync::fetch(remote.as_deref(), json),
        Cmd::Pull { remote, json } => sync::pull(remote.as_deref(), json),
        Cmd::Push {
            remote,
            force,
            bookmark,
            delete,
            json,
        } => match delete {
            Some(name) => sync::push_delete(remote.as_deref(), &name, json),
            None => sync::push(remote.as_deref(), force, bookmark.as_deref(), json),
        },
        Cmd::Serve {
            root,
            bind,
            tokens,
            tls_cert,
            tls_key,
        } => sync::serve(root, &bind, tokens, tls_cert.zip(tls_key)),
        Cmd::Identity { cmd } => match cmd {
            IdentityCmd::Create {
                name,
                email,
                local,
                expires,
            } => identity::create(name, email, local, expires),
            IdentityCmd::Show => identity::show(),
            IdentityCmd::Export { path } => identity::export(path),
            IdentityCmd::SignChallenge { challenge, json } => {
                identity::sign_challenge(&challenge, json)
            }
            IdentityCmd::Rotate => identity::rotate(),
            IdentityCmd::Renew { expires } => identity::renew(expires),
            IdentityCmd::Revoke { key, reason } => identity::revoke(key.as_deref(), &reason),
            IdentityCmd::Delegate { cmd } => match cmd {
                DelegateCmd::Add { identity_file } => identity::delegate_add(&identity_file),
                DelegateCmd::Remove { key } => identity::delegate_remove(&key),
                DelegateCmd::List => identity::delegate_list(),
            },
        },
        Cmd::Git {
            cmd: GitCmd::Export { git_dir, branch },
        } => sync::git_export(&git_dir, branch.as_deref()),
        Cmd::Git {
            cmd: GitCmd::Fetch { url, branch },
        } => sync::git_fetch(&url, &branch),
        Cmd::Git {
            cmd: GitCmd::Push { url, branch },
        } => sync::git_push(&url, &branch),
        Cmd::Git {
            cmd:
                GitCmd::Import {
                    git_dir,
                    dest,
                    branch,
                },
        } => sync::git_import(&git_dir, &dest, &branch),
        Cmd::Git {
            cmd: GitCmd::Verify { git_dir, branch },
        } => sync::git_verify(&git_dir, &branch),
        Cmd::Policy { cmd } => match cmd {
            PolicyCmd::Init => identity::policy_init(),
            PolicyCmd::Show { json } => identity::policy_show(json),
            PolicyCmd::Grant {
                identity_file,
                pattern,
                out,
            } => identity::policy_grant(&identity_file, pattern.as_deref(), out),
            PolicyCmd::Revoke { key, out } => identity::policy_revoke(&key, out),
            PolicyCmd::Root { cmd } => match cmd {
                RootCmd::Add { identity_file, out } => {
                    identity::policy_root_add(&identity_file, out)
                }
                RootCmd::Remove { key, out } => identity::policy_root_remove(&key, out),
                RootCmd::Threshold { n, out } => identity::policy_threshold(n, out),
            },
            PolicyCmd::Sign { proposal, out } => identity::policy_sign(&proposal, out),
        },
        Cmd::Seal {
            changes,
            proposal: Some(url),
            json,
        } if changes.is_empty() => proposal::seal(&url, json),
        Cmd::Seal { changes, json, .. } => identity::seal(&changes, json),
        Cmd::Proposal { cmd } => match cmd {
            ProposalCmd::Show { url, json } => proposal::show(&url, json),
            ProposalCmd::Land { url, force } => proposal::land(&url, force),
        },
        Cmd::Verify { change, json } => identity::verify(change.as_deref(), json),
        Cmd::Config { key, value, user } => identity::config(&key, &value, user),
    }
}

#[cfg(test)]
mod help_tests {
    use super::Cli;
    use clap::CommandFactory;

    /// Every command and every argument explains itself, so `--help`,
    /// completions and the man pages are complete.
    #[test]
    fn every_command_and_argument_has_help() {
        fn walk(cmd: &clap::Command, path: &str, missing: &mut Vec<String>) {
            let here = format!("{path} {}", cmd.get_name()).trim().to_string();
            if cmd.get_about().is_none() && path != "" {
                missing.push(format!("{here} (command)"));
            }
            for a in cmd.get_arguments() {
                let id = a.get_id().as_str();
                if id == "help" || id == "version" || a.is_global_set() && path != "" {
                    continue;
                }
                if a.get_help().is_none() && a.get_long_help().is_none() {
                    missing.push(format!("{here} {id}"));
                }
            }
            for sub in cmd.get_subcommands() {
                walk(sub, &here, missing);
            }
        }
        let mut missing = Vec::new();
        walk(&Cli::command(), "", &mut missing);
        assert!(
            missing.is_empty(),
            "{} without help:\n{}",
            missing.len(),
            missing.join("\n")
        );
    }
}