//! `heph` — the CLI surface (tech-spec §1). A thin client of the local
//! `hephd`: it never touches SQLite, only the daemon socket.
//!
//! Per the three-surface model ([[design]] §4), the CLI is the **task
//! capture/scripting** surface and exposes the **complete daemon API** — every
//! RPC method has a command. Structured task fields are flags, with human dates
//! (`--do tomorrow`) and recurrence (`--recur weekly`) parsed in [`datespec`].

use std::path::PathBuf;

use anyhow::{bail, Context, Result};
use clap::{Parser, Subcommand};
use serde_json::{json, Value};

use heph_core::{Node, RankedTask, Task};
use hephd::{datespec, default_socket_path, Client, DeviceFlow, KeyringTokenStore, TokenStore};

mod service;

#[derive(Parser, Debug)]
#[command(name = "heph", version = heph_core::VERSION, about)]
struct Cli {
    /// Path to the hephd unix socket (defaults to the standard runtime path).
    #[arg(long, global = true)]
    socket: Option<PathBuf>,

    #[command(subcommand)]
    command: Command,
}

#[derive(Subcommand, Debug)]
enum Command {
    /// Show the Tactical "what is next?" ranking.
    Next {
        /// Restrict to a project node id.
        #[arg(long)]
        scope: Option<String>,
        /// Maximum rows (red items always show).
        #[arg(long, default_value_t = 5)]
        limit: usize,
    },
    /// Create a committed task (auto-creates its canonical context doc).
    Task {
        /// The task title.
        title: String,
        /// Attention-state: white|orange|red|blue.
        #[arg(short = 'a', long)]
        attention: Option<String>,
        /// Do-date (earliest-actionable): today|tomorrow|+3d|fri|YYYY-MM-DD.
        #[arg(long)]
        do_date: Option<String>,
        /// Late-on (the sole urgency marker): same date forms as --do-date.
        #[arg(long)]
        late_on: Option<String>,
        /// Project name to file it under (must already exist).
        #[arg(long)]
        project: Option<String>,
        /// Recurrence: a preset (daily|weekly|monthly|yearly|weekdays) or NL
        /// ("every 3 days", "every fri").
        #[arg(long)]
        recur: Option<String>,
        /// A raw RFC-5545 RRULE (overrides --recur).
        #[arg(long)]
        rrule: Option<String>,
    },
    /// Enumerate the outstanding set (the Organizational survey).
    List {
        /// Restrict to a project node id.
        #[arg(long)]
        scope: Option<String>,
        /// Restrict to a project by NAME (subtree-expanded). e.g. --project Hephaestus.
        #[arg(long)]
        project: Option<String>,
        /// Only this attention-state: white|orange|red|blue.
        #[arg(short = 'a', long)]
        attention: Option<String>,
        /// Hide on-deck (blue) items.
        #[arg(long)]
        no_blue: bool,
        /// Print raw JSON rows (node id, canonical-context id, scalars) for scripting/agents.
        #[arg(long)]
        json: bool,
    },
    /// Run a built-in filter view (tech-spec §8.2); omit the name to list views.
    View {
        /// View name: tom|ondeck|chores|work|tasks. Omit to list all views.
        name: Option<String>,
    },
    /// Mark a task done (recurring tasks roll forward).
    Done {
        /// Task node id.
        id: String,
    },
    /// Mark a task dropped.
    Drop {
        /// Task node id.
        id: String,
    },
    /// Skip a recurring task's current occurrence (advance without logging).
    Skip {
        /// Task node id.
        id: String,
    },
    /// Set a task's attention-state.
    Attention {
        /// Task node id.
        id: String,
        /// white|orange|red|blue.
        attention: String,
    },
    /// Reschedule a task: change do-date / late-on / recurrence (use `none` to
    /// clear a field; omit to leave it unchanged). Also re-attentions / re-files.
    Edit {
        /// Task node id.
        id: String,
        /// Do-date or `none`.
        #[arg(long)]
        do_date: Option<String>,
        /// Late-on or `none`.
        #[arg(long)]
        late_on: Option<String>,
        /// Recurrence (preset/NL) or `none`.
        #[arg(long)]
        recur: Option<String>,
        /// A raw RRULE or `none`.
        #[arg(long)]
        rrule: Option<String>,
        /// Set attention: white|orange|red|blue.
        #[arg(short = 'a', long)]
        attention: Option<String>,
        /// Re-file under a project (by name); `none` unfiles the task.
        #[arg(long)]
        project: Option<String>,
    },
    /// Promote a context-item line into a committed task.
    Promote {
        /// The container node id (the doc holding the `- [ ]` line).
        container_id: String,
        /// 1-based index of the context item to promote (document order).
        item_ref: usize,
        /// Attention for the new task: white|orange|red|blue.
        #[arg(short = 'a', long)]
        attention: Option<String>,
        /// Project name to file the new task under.
        #[arg(long)]
        project: Option<String>,
    },
    /// Show a node (and, if it is a task, its scalars).
    Show {
        /// Node id.
        id: String,
    },
    /// Append to a task's log (with text) or print its latest entries (without).
    Log {
        /// Task node id.
        id: String,
        /// Text to append; if omitted, the latest entries are printed.
        text: Vec<String>,
        /// How many entries to print (read mode).
        #[arg(short = 'n', long, default_value_t = 10)]
        n: usize,
    },
    /// Read or edit a task's canonical-context doc body **by task id** — no
    /// manual `canonical_context_id` lookup. With neither flag, prints the body.
    Context {
        /// Task node id.
        id: String,
        /// Replace the body with this text (`-` reads from stdin).
        #[arg(long)]
        body: Option<String>,
        /// Append this text to the body (separated by a blank line).
        #[arg(long)]
        append: Option<String>,
    },
    /// Working-set health — the §6.2 tensions (orange vs 6, active vs ~30, …).
    Health,
    /// Create a document node.
    Doc {
        /// The document title.
        title: String,
        /// Markdown body.
        #[arg(long)]
        body: Option<String>,
    },
    /// Node operations (update, tombstone).
    Node {
        #[command(subcommand)]
        action: NodeAction,
    },
    /// Fetch a node by id and print it as JSON.
    Get {
        /// Node id.
        id: String,
    },
    /// Resolve a wiki-link title to a node (exact, alias-then-title).
    Resolve {
        /// The title or alias.
        title: String,
    },
    /// Full-text search over titles and bodies.
    Search {
        /// FTS5 query.
        query: String,
    },
    /// Open (or create) the journal for an ISO date (YYYY-MM-DD).
    Journal {
        /// The ISO date.
        date: String,
    },
    /// List a node's outgoing links.
    Links {
        /// Node id.
        id: String,
    },
    /// List a node's backlinks.
    Backlinks {
        /// Node id.
        id: String,
    },
    /// Link operations (add).
    Link {
        #[command(subcommand)]
        action: LinkAction,
    },
    /// Project operations (add).
    Project {
        #[command(subcommand)]
        action: ProjectAction,
    },
    /// Tag operations: add/remove a tag on a node, or list tags.
    Tag {
        #[command(subcommand)]
        action: TagAction,
    },
    /// Force a sync cycle (or show sync status with --status).
    Sync {
        /// Show status instead of syncing.
        #[arg(long)]
        status: bool,
    },
    /// List merge conflicts, or resolve one.
    Conflicts {
        #[command(subcommand)]
        action: Option<ConflictAction>,
    },
    /// Export the store to a directory tree of .md files.
    Export {
        /// Destination directory (created if needed).
        dir: PathBuf,
    },
    /// One-time: rewrite legacy `[[Name]]` body links to the canonical
    /// `[[node-id]]` form (tech-spec §8.4). Idempotent.
    MigrateLinks,
    /// Manage the hephd daemon as an OS service (launchd / systemd).
    Daemon {
        #[command(subcommand)]
        action: service::DaemonAction,
    },
    /// Authenticate this device with a sync hub (OAuth 2.0 device-code flow).
    Auth {
        #[command(subcommand)]
        action: AuthAction,
    },
}

#[derive(Subcommand, Debug)]
enum NodeAction {
    /// Update a node's title and/or body.
    Update {
        /// Node id.
        id: String,
        /// New title.
        #[arg(long)]
        title: Option<String>,
        /// New markdown body (or `-` to read the body from stdin).
        #[arg(long)]
        body: Option<String>,
    },
    /// Tombstone (soft-delete) a node.
    Rm {
        /// Node id.
        id: String,
    },
}

#[derive(Subcommand, Debug)]
enum LinkAction {
    /// Add a typed link between two nodes.
    Add {
        /// Source node id.
        src: String,
        /// Destination node id.
        dst: String,
        /// Link type: blocks|parent|tagged|in-project|context-of|…
        link_type: String,
    },
}

#[derive(Subcommand, Debug)]
enum ProjectAction {
    /// Create a project node (optionally under a parent project).
    Add {
        /// Project name.
        name: String,
        /// Parent project name (creates a `parent` link).
        #[arg(long)]
        parent: Option<String>,
    },
    /// List all projects.
    List,
}

#[derive(Subcommand, Debug)]
enum TagAction {
    /// Tag a node.
    Add {
        /// Node id to tag.
        node: String,
        /// Tag name.
        tag: String,
    },
    /// Remove a tag from a node.
    Rm {
        /// Node id.
        node: String,
        /// Tag name.
        tag: String,
    },
    /// List a node's tags, or every tag in the store (with no node).
    List {
        /// Node id (omit to list all tags).
        node: Option<String>,
    },
}

#[derive(Subcommand, Debug)]
enum ConflictAction {
    /// Resolve a conflict by choosing the local or remote value.
    Resolve {
        /// Conflict id.
        id: String,
        /// `local` or `remote`.
        choice: String,
    },
}

#[derive(Subcommand, Debug)]
enum AuthAction {
    /// Log in via the device-code flow; caches the bearer token for hub sync.
    Login {
        /// Hub/server URL this token is for (keys the credential store entry).
        #[arg(long)]
        hub_url: String,
        /// OIDC issuer, e.g. https://authentik.ops.eblu.me/application/o/heph/.
        #[arg(long)]
        issuer: String,
        /// OIDC client id this device authenticates as.
        #[arg(long)]
        client_id: String,
        /// Scopes to request (`offline_access` yields a refresh token).
        #[arg(long, default_value = "openid offline_access")]
        scope: String,
    },
    /// Forget the cached token for a hub.
    Logout {
        /// Hub/server URL whose cached token to remove.
        #[arg(long)]
        hub_url: String,
    },
}

/// Run the device-code flow (or clear a token) — no daemon needed.
fn run_auth(action: AuthAction) -> Result<()> {
    match action {
        AuthAction::Login {
            hub_url,
            issuer,
            client_id,
            scope,
        } => {
            let flow = DeviceFlow::discover(&issuer, &client_id)?;
            let auth = flow.start(&scope)?;
            let uri = auth
                .verification_uri_complete
                .as_deref()
                .unwrap_or(&auth.verification_uri);
            println!(
                "To authorize hephaestus, visit:\n  {uri}\nand enter code: {}\n\nWaiting…",
                auth.user_code
            );
            let token = flow.poll(&auth, std::thread::sleep)?;
            KeyringTokenStore::new(hub_url.as_str()).save(&token)?;
            println!("Logged in. Token cached for {hub_url}.");
        }
        AuthAction::Logout { hub_url } => {
            KeyringTokenStore::new(hub_url.as_str()).clear()?;
            println!("Logged out of {hub_url}.");
        }
    }
    Ok(())
}

fn main() -> Result<()> {
    let cli = Cli::parse();

    // `daemon` manages the OS service; it must not connect to a daemon.
    if let Command::Daemon { action } = &cli.command {
        return service::run(action);
    }
    // `auth` runs locally (device-code flow + keyring); it needs no daemon.
    if let Command::Auth { action } = cli.command {
        return run_auth(action);
    }

    let socket = cli.socket.unwrap_or_else(default_socket_path);
    let mut client = Client::connect(&socket)?;

    match cli.command {
        Command::Next { scope, limit } => {
            let result = client.call("next", json!({ "scope": scope, "limit": limit }))?;
            print_rows(result)?;
        }
        Command::Task {
            title,
            attention,
            do_date,
            late_on,
            project,
            recur,
            rrule,
        } => {
            let recurrence = recurrence_value(recur.as_deref(), rrule.as_deref())?;
            let project_id = resolve_project(&mut client, project.as_deref())?;
            let result = client.call(
                "task.create",
                json!({
                    "title": title,
                    "attention": attention,
                    "do_date": opt_date_ms(do_date.as_deref())?,
                    "late_on": opt_date_ms(late_on.as_deref())?,
                    "project_id": project_id,
                    "recurrence": recurrence,
                }),
            )?;
            let task: Task = serde_json::from_value(result)?;
            println!("Created task {} \"{title}\"", task.node_id);
        }
        Command::List {
            scope,
            project,
            attention,
            no_blue,
            json,
        } => {
            // `list` takes a ListFilter (tech-spec §8.2). Map the flags: a single
            // `--scope` id or `--project` NAME (resolved + subtree-expanded by the
            // daemon), a single `--attention` whitelist, and `--no-blue`.
            let mut filter = json!({});
            if let Some(s) = scope {
                filter["scope"] = json!([s]);
            }
            if let Some(p) = project {
                filter["project"] = json!(p);
            }
            if let Some(a) = attention {
                filter["attention_in"] = json!([a]);
            }
            if no_blue {
                filter["attention_not"] = json!(["blue"]);
            }
            let result = client.call("list", filter)?;
            if json {
                println!("{}", serde_json::to_string_pretty(&result)?);
            } else {
                print_rows(result)?;
            }
        }
        Command::View { name } => match name {
            Some(name) => {
                let result = client.call("view", json!({ "name": name }))?;
                print_rows(result)?;
            }
            None => {
                println!("Available views (heph view <name>):");
                for v in heph_core::BUILTIN_VIEWS {
                    println!("  {:<8} {}", v.name, v.title);
                }
            }
        },
        Command::Done { id } => {
            set_state(&mut client, &id, "done")?;
        }
        Command::Drop { id } => {
            set_state(&mut client, &id, "dropped")?;
        }
        Command::Skip { id } => {
            client.call("task.skip", json!({ "id": id }))?;
            println!("Skipped occurrence of {id}");
        }
        Command::Attention { id, attention } => {
            client.call(
                "task.set_attention",
                json!({ "id": id, "attention": attention }),
            )?;
            println!("{id} attention → {attention}");
        }
        Command::Edit {
            id,
            do_date,
            late_on,
            recur,
            rrule,
            attention,
            project,
        } => {
            let mut patch = serde_json::Map::new();
            patch.insert("id".into(), json!(id));
            if let Some(v) = sched_date(do_date.as_deref())? {
                patch.insert("do_date".into(), v);
            }
            if let Some(v) = sched_date(late_on.as_deref())? {
                patch.insert("late_on".into(), v);
            }
            let recur_spec = recur.or(rrule);
            if let Some(v) = sched_recurrence(recur_spec.as_deref())? {
                patch.insert("recurrence".into(), v);
            }
            if patch.len() > 1 {
                client.call("task.set_schedule", Value::Object(patch))?;
            }
            if let Some(a) = attention {
                client.call("task.set_attention", json!({ "id": id, "attention": a }))?;
            }
            if let Some(spec) = project.as_deref() {
                // Re-file (or unfile with `none`) via the move-to-project path,
                // which tombstones the old `in-project` link rather than piling
                // a second one on top of it.
                let project_id = match spec {
                    "none" | "clear" => None,
                    name => resolve_project(&mut client, Some(name))?,
                };
                client.call(
                    "task.set_project",
                    json!({ "id": id, "project_id": project_id }),
                )?;
            }
            println!("Edited task {id}");
        }
        Command::Promote {
            container_id,
            item_ref,
            attention,
            project,
        } => {
            let project_id = resolve_project(&mut client, project.as_deref())?;
            let result = client.call(
                "task.promote",
                json!({
                    "container_id": container_id,
                    "item_ref": item_ref,
                    "attention": attention,
                    "project": project_id,
                }),
            )?;
            let task: Task = serde_json::from_value(result)?;
            println!("Promoted item {item_ref} → task {}", task.node_id);
        }
        Command::Show { id } => {
            let node = client.call("node.get", json!({ "id": id }))?;
            println!("{}", serde_json::to_string_pretty(&node)?);
            if node.get("kind").and_then(Value::as_str) == Some("task") {
                let task = client.call("task.get", json!({ "id": id }))?;
                println!("task: {}", serde_json::to_string_pretty(&task)?);
            }
        }
        Command::Log { id, text, n } => {
            if text.is_empty() {
                let entries = client.call("log.tail", json!({ "task_id": id, "n": n }))?;
                let entries: Vec<String> = serde_json::from_value(entries)?;
                if entries.is_empty() {
                    println!("(no log entries)");
                }
                for e in &entries {
                    println!("{e}");
                }
            } else {
                let line = text.join(" ");
                client.call("log.append", json!({ "task_id": id, "text": line }))?;
                println!("Logged to {id}");
            }
        }
        Command::Context { id, body, append } => {
            let doc_id = canonical_context_id(&mut client, &id)?;
            match (body, append) {
                (Some(_), Some(_)) => bail!("pass only one of --body / --append"),
                (Some(body), None) => {
                    let body = read_body_arg(Some(body))?;
                    client.call("node.update", json!({ "id": doc_id, "body": body }))?;
                    println!("Set context of {id}");
                }
                (None, Some(text)) => {
                    let current = context_body(&mut client, &doc_id)?;
                    let combined = if current.trim().is_empty() {
                        text
                    } else {
                        format!("{}\n\n{text}", current.trim_end())
                    };
                    client.call("node.update", json!({ "id": doc_id, "body": combined }))?;
                    println!("Appended to context of {id}");
                }
                (None, None) => {
                    let current = context_body(&mut client, &doc_id)?;
                    if current.trim().is_empty() {
                        println!("(empty context)");
                    } else {
                        println!("{}", current.trim_end());
                    }
                }
            }
        }
        Command::Health => {
            let h = client.call("health", json!({}))?;
            println!(
                "orange {}  active {}  on-deck {}  conflicts {}  sync {}",
                num(&h, "orange_count"),
                num(&h, "active_count"),
                num(&h, "on_deck_count"),
                num(&h, "conflict_count"),
                h.get("sync_status").and_then(Value::as_str).unwrap_or("?"),
            );
        }
        Command::Doc { title, body } => {
            let result = client.call(
                "node.create",
                json!({ "kind": "doc", "title": title, "body": body }),
            )?;
            let node: Node = serde_json::from_value(result)?;
            println!("Created doc {} \"{}\"", node.id, node.title);
        }
        Command::Node { action } => match action {
            NodeAction::Update { id, title, body } => {
                let body = read_body_arg(body)?;
                let result = client.call(
                    "node.update",
                    json!({ "id": id, "title": title, "body": body }),
                )?;
                let node: Node = serde_json::from_value(result)?;
                println!("Updated {} \"{}\"", node.id, node.title);
            }
            NodeAction::Rm { id } => {
                client.call("node.tombstone", json!({ "id": id }))?;
                println!("Tombstoned {id}");
            }
        },
        Command::Get { id } => {
            let result = client.call("node.get", json!({ "id": id }))?;
            println!("{}", serde_json::to_string_pretty(&result)?);
        }
        Command::Resolve { title } => {
            let result = client.call("node.resolve", json!({ "title": title }))?;
            if result.is_null() {
                println!("(no match)");
            } else {
                let node: Node = serde_json::from_value(result)?;
                println!("{}  [{}]  {}", node.id, node.kind.as_str(), node.title);
            }
        }
        Command::Search { query } => {
            let result = client.call("search", json!({ "query": query }))?;
            let nodes: Vec<Node> = serde_json::from_value(result)?;
            if nodes.is_empty() {
                println!("No matches.");
            }
            for n in &nodes {
                println!("{}  [{}]  {}", n.id, n.kind.as_str(), n.title);
            }
        }
        Command::Journal { date } => {
            let result = client.call("journal.open_or_create", json!({ "date": date }))?;
            let node: Node = serde_json::from_value(result)?;
            println!("Journal {} ({})", node.title, node.id);
        }
        Command::Links { id } => {
            print_links(client.call("links.outgoing", json!({ "id": id }))?);
        }
        Command::Backlinks { id } => {
            print_links(client.call("links.backlinks", json!({ "id": id }))?);
        }
        Command::Link { action } => match action {
            LinkAction::Add {
                src,
                dst,
                link_type,
            } => {
                client.call(
                    "links.add",
                    json!({ "src": src, "dst": dst, "link_type": link_type }),
                )?;
                println!("Linked {src} -[{link_type}]-> {dst}");
            }
        },
        Command::Project { action } => match action {
            ProjectAction::Add { name, parent } => {
                let result =
                    client.call("node.create", json!({ "kind": "project", "title": name }))?;
                let node: Node = serde_json::from_value(result)?;
                if let Some(parent) = parent {
                    let pid = resolve_project(&mut client, Some(&parent))?
                        .context("parent project not found")?;
                    client.call(
                        "links.add",
                        json!({ "src": node.id, "dst": pid, "link_type": "parent" }),
                    )?;
                }
                println!("Created project {} \"{}\"", node.id, node.title);
            }
            ProjectAction::List => {
                let result = client.call("node.list", json!({ "kind": "project" }))?;
                let nodes: Vec<Node> = serde_json::from_value(result)?;
                if nodes.is_empty() {
                    println!("No projects.");
                }
                for n in &nodes {
                    println!("{}  {}", n.id, n.title);
                }
            }
        },
        Command::Tag { action } => match action {
            TagAction::Add { node, tag } => {
                let result = client.call("tag.add", json!({ "node_id": node, "tag": tag }))?;
                let t: Node = serde_json::from_value(result)?;
                println!("{node} tagged #{}", t.title);
            }
            TagAction::Rm { node, tag } => {
                client.call("tag.remove", json!({ "node_id": node, "tag": tag }))?;
                println!("{node} untagged #{tag}");
            }
            TagAction::List { node } => {
                let tags: Vec<String> = match node {
                    Some(node) => {
                        let result = client.call("tag.list", json!({ "node_id": node }))?;
                        serde_json::from_value(result)?
                    }
                    None => {
                        let result = client.call("node.list", json!({ "kind": "tag" }))?;
                        let nodes: Vec<Node> = serde_json::from_value(result)?;
                        nodes.into_iter().map(|n| n.title).collect()
                    }
                };
                if tags.is_empty() {
                    println!("(no tags)");
                }
                for t in &tags {
                    println!("#{t}");
                }
            }
        },
        Command::Sync { status } => {
            let method = if status { "sync.status" } else { "sync.now" };
            let result = client.call(method, json!({}))?;
            println!("{}", serde_json::to_string_pretty(&result)?);
        }
        Command::Conflicts { action } => match action {
            None => {
                let result = client.call("conflicts.list", json!({}))?;
                let arr = result.as_array().cloned().unwrap_or_default();
                if arr.is_empty() {
                    println!("No conflicts.");
                }
                for c in &arr {
                    println!("{}", serde_json::to_string(c)?);
                }
            }
            Some(ConflictAction::Resolve { id, choice }) => {
                client.call("conflicts.resolve", json!({ "id": id, "choice": choice }))?;
                println!("Resolved {id} → {choice}");
            }
        },
        Command::Export { dir } => {
            let path = dir
                .to_str()
                .context("export path is not valid UTF-8")?
                .to_string();
            let result = client.call("export", json!({ "path": path }))?;
            let count = result.get("count").and_then(Value::as_u64).unwrap_or(0);
            println!("Exported {count} nodes to {}", dir.display());
        }
        Command::MigrateLinks => {
            let result = client.call("migrate.wikilinks", json!({}))?;
            let n = result.as_u64().unwrap_or(0);
            println!("Rewrote legacy [[Name]] links to [[id]] in {n} node(s).");
        }
        Command::Auth { .. } => unreachable!("auth is handled before connecting"),
        Command::Daemon { .. } => unreachable!("daemon is handled before connecting"),
    }
    Ok(())
}

/// Parse an optional human date into epoch-ms JSON (for `task.create`).
fn opt_date_ms(spec: Option<&str>) -> Result<Option<i64>> {
    spec.map(datespec::parse_date_ms).transpose()
}

/// A `task.set_schedule` date field value: `Some(null)` to clear (`"none"`),
/// `Some(<ms>)` to set, `None` to omit (leave unchanged).
fn sched_date(spec: Option<&str>) -> Result<Option<Value>> {
    match spec {
        None => Ok(None),
        Some("none") => Ok(Some(Value::Null)),
        Some(s) => Ok(Some(json!(datespec::parse_date_ms(s)?))),
    }
}

/// A `task.set_schedule` recurrence value, same tri-state as [`sched_date`].
fn sched_recurrence(spec: Option<&str>) -> Result<Option<Value>> {
    match spec {
        None => Ok(None),
        Some("none") => Ok(Some(Value::Null)),
        Some(s) => Ok(Some(json!(datespec::parse_recurrence(s)?))),
    }
}

/// Recurrence for `task.create`: a raw `--rrule` wins, else parse `--recur`.
fn recurrence_value(recur: Option<&str>, rrule: Option<&str>) -> Result<Option<String>> {
    if let Some(raw) = rrule {
        return Ok(Some(raw.to_string()));
    }
    recur.map(datespec::parse_recurrence).transpose()
}

/// Resolve a project **name** to its node id, erroring if no project matches.
/// Matching is case-insensitive and prefix-fuzzy when unambiguous (server-side,
/// shared with `heph list --project`); an exact title always wins outright.
fn resolve_project(client: &mut Client, name: Option<&str>) -> Result<Option<String>> {
    let Some(name) = name else { return Ok(None) };
    let result = client.call("project.resolve", json!({ "name": name }))?;
    if result.is_null() {
        bail!("no project named {name:?} (create it with: heph project add {name:?})");
    }
    let node: Node = serde_json::from_value(result)?;
    Ok(Some(node.id))
}

/// Resolve a task's canonical-context doc id by walking its outgoing links.
/// Errors if the node has no such doc (e.g. it isn't a task).
fn canonical_context_id(client: &mut Client, task_id: &str) -> Result<String> {
    let links = client.call("links.outgoing", json!({ "id": task_id }))?;
    let dst = links
        .as_array()
        .into_iter()
        .flatten()
        .find(|l| l.get("link_type").and_then(Value::as_str) == Some("canonical-context"))
        .and_then(|l| l.get("dst_id").and_then(Value::as_str));
    match dst {
        Some(id) => Ok(id.to_string()),
        None => bail!("{task_id} has no canonical-context doc (is it a task?)"),
    }
}

/// Fetch a context doc's current body (empty string when unset).
fn context_body(client: &mut Client, doc_id: &str) -> Result<String> {
    let node = client.call("node.get", json!({ "id": doc_id }))?;
    Ok(node
        .get("body")
        .and_then(Value::as_str)
        .unwrap_or("")
        .to_string())
}

/// `--body -` reads the body from stdin; otherwise pass it through.
fn read_body_arg(body: Option<String>) -> Result<Option<String>> {
    match body.as_deref() {
        Some("-") => {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s)?;
            Ok(Some(s))
        }
        _ => Ok(body),
    }
}

fn set_state(client: &mut Client, id: &str, state: &str) -> Result<()> {
    client.call("task.set_state", json!({ "id": id, "state": state }))?;
    println!("{id} → {state}");
    Ok(())
}

fn num(v: &Value, key: &str) -> u64 {
    v.get(key).and_then(Value::as_u64).unwrap_or(0)
}

/// Print a list of `RankedTask` rows (shared by `next` and `list`).
fn print_rows(result: Value) -> Result<()> {
    let tasks: Vec<RankedTask> = serde_json::from_value(result)?;
    if tasks.is_empty() {
        println!("Nothing actionable right now.");
    }
    for t in &tasks {
        println!("{}", format_row(t));
    }
    Ok(())
}

fn print_links(result: Value) {
    let arr = result.as_array().cloned().unwrap_or_default();
    if arr.is_empty() {
        println!("(no links)");
    }
    for l in &arr {
        let ty = l.get("link_type").and_then(Value::as_str).unwrap_or("?");
        let src = l.get("src_id").and_then(Value::as_str).unwrap_or("?");
        let dst = l.get("dst_id").and_then(Value::as_str).unwrap_or("?");
        println!("{src} -[{ty}]-> {dst}");
    }
}

/// One concise Tactical row: attention tag, title, and human do/late context.
fn format_row(t: &RankedTask) -> String {
    let tag = t
        .attention
        .map(|a| format!("[{}]", serde_json::to_value(a).unwrap().as_str().unwrap()))
        .unwrap_or_else(|| "[ ]".to_string());
    let mut extra = Vec::new();
    if let Some(d) = t.do_date {
        extra.push(format!("do:{}", datespec::fmt_date(d)));
    }
    if let Some(l) = t.late_on {
        extra.push(format!("late:{}", datespec::fmt_date(l)));
    }
    let suffix = if extra.is_empty() {
        String::new()
    } else {
        format!("  ({})", extra.join(", "))
    };
    format!("{tag} {}{suffix}  {}", t.title, t.node_id)
}