zshrs 0.12.16

//! Port of `_complete_help` from
//! `Completion/Base/Widget/_complete_help`.
//!
//! Full upstream body (92 lines, abridged):
//! ```text
//! sh: 1  #compdef -k complete-word \C-xh
//! sh: 3  _complete_help() {
//! sh:  5    eval "$_comp_setup"
//! sh:  7    local _sort_tags=_help_sort_tags text i j k tmp
//! sh:  8    typeset -A help_funcs help_tags help_sfuncs help_styles
//! sh: 10    local -H _help_scan_funcstack="main_complete|complete|approximate|normal"
//! sh: 11    local -H _help_filter_funcstack="alternative|call_function|describe|dispatch|wanted|requested|all_labels|next_label"
//! sh: 13    {
//! sh: 14      compadd() { return 1 }
//! sh: 15      compcall() { _help_sort_tags use-compctl }
//! sh: 16      zstyle() { … capture-via-funcstack-walk … }
//! sh: 50      ${1:-_main_complete}
//! sh: 51    } always {
//! sh: 52      unfunction compadd compcall zstyle
//! sh: 53    }
//! sh: 55    for i in "${(@ok)help_funcs}"; do … zformat -a tmp '  (' … done
//! sh: 66    if [[ ${NUMERIC:-1} -ne 1 ]]; then … styles report … fi
//! sh: 78    compstate[list]='list force'
//! sh: 79    compstate[insert]=''
//! sh: 80    compadd -UX "$text[2,-1]" -n ''
//! sh: 83  _help_sort_tags() { … record help_funcs/help_tags; comptry "$@" … }
//! ```
//!
//! Diagnostic widget: runs the completion machinery with `compadd`,
//! `compcall` and `zstyle` shadowed, then prints which tags (and,
//! with a non-1 numeric argument, which styles) each completion
//! function consulted. The tag report is driven by the real
//! `_help_sort_tags` hook: `$_sort_tags` names it, so `_tags`
//! (`Base/Core/_tags`) invokes it for every tag registration during
//! `_main_complete`, and it accumulates `help_funcs`/`help_tags`.
//!
//! The shared state (`help_funcs`, `help_tags`, `help_sfuncs`,
//! `help_styles`, `_sort_tags`, `_help_scan_funcstack`,
//! `_help_filter_funcstack`) lives in ordinary shell params here — the
//! source keeps them function-local and reaches them from
//! `_help_sort_tags` by zsh dynamic scoping, which the in-process Rust
//! dispatch emulates via the global param table.
//!
//! Honest substrate gaps:
//!   * `zstyle`/`compcall` are Rust builtins; a shadow installed via
//!     `_shadow` backs up their shfunctab entries but `_main_complete`
//!     dispatches them as builtins, bypassing any shell-function
//!     override. So `help_sfuncs`/`help_styles` are not populated and
//!     the styles report (the `NUMERIC != 1` branch) is empty. The
//!     branch is ported faithfully so it produces output once
//!     builtin-call interception exists.
//!   * `compadd`'s `{ return 1 }` shadow (suppress real matches during
//!     the help run) likewise cannot intercept the builtin; matches the
//!     inner completion adds are not suppressed here.
//!   * `_help_sort_tags`'s `$f` derivation walks `$funcstack`; the
//!     result is only as accurate as the compsys call chain present on
//!     `FUNCSTACK` when compsys functions are dispatched in-process.

use crate::ported::exec::dispatch_function_call;
use crate::ported::modules::zutil::bin_zformat;
use crate::ported::params::{getaparam, getsparam, setaparam, setsparam};
use crate::ported::zle::compcore::set_compstate_str;
use crate::ported::zle::complete::bin_compadd;
use crate::ported::zle::computil::bin_comptry;
use crate::ported::zsh_h::{options, MAX_OPS};

// sh:10 — local -H _help_scan_funcstack="main_complete|complete|approximate|normal"
const HELP_SCAN_FUNCSTACK: &str = "main_complete|complete|approximate|normal";
// sh:11 — local -H _help_filter_funcstack="alternative|call_function|describe|dispatch|wanted|requested|all_labels|next_label"
const HELP_FILTER_FUNCSTACK: &str =
    "alternative|call_function|describe|dispatch|wanted|requested|all_labels|next_label";

fn make_ops() -> options {
    options {
        ind: [0u8; MAX_OPS],
        args: Vec::new(),
        argscount: 0,
        argsalloc: 0,
    }
}

// The four associative arrays are stored as flat `[k, v, k, v, …]`
// plain arrays (`setaparam`/`getaparam` — the same interleaved layout
// `_complete` uses for `$_comps`), because `getaparam` only reads
// `PM_ARRAY` params: a `PM_HASHED` param (what `sethparam` builds)
// reads back as `None`. The pairing is internal-only, so this is
// behaviourally identical to the upstream `typeset -A` while staying
// on the array-read path that actually round-trips.

/// Flat-`(k,v)` associative lookup (`$assoc[$key]`).
fn assoc_get(name: &str, key: &str) -> String {
    getaparam(name)
        .unwrap_or_default()
        .chunks(2)
        .find(|kv| kv.first().map(|k| k == key).unwrap_or(false))
        .and_then(|kv| kv.get(1).cloned())
        .unwrap_or_default()
}

/// Flat-`(k,v)` associative store (`$assoc[$key]=$val`), preserving
/// other keys.
fn assoc_set(name: &str, key: &str, val: &str) {
    let mut flat = getaparam(name).unwrap_or_default();
    let mut i = 0;
    let mut done = false;
    while i + 1 < flat.len() {
        if flat[i] == key {
            flat[i + 1] = val.to_string();
            done = true;
            break;
        }
        i += 2;
    }
    if !done {
        flat.push(key.to_string());
        flat.push(val.to_string());
    }
    let _ = setaparam(name, flat);
}

/// `${(@ok)assoc}` — the keys of an associative array, sorted.
fn assoc_keys_sorted(name: &str) -> Vec<String> {
    let mut keys: Vec<String> = getaparam(name)
        .unwrap_or_default()
        .chunks(2)
        .filter_map(|kv| kv.first().cloned())
        .collect();
    keys.sort();
    keys
}

/// sh:57-63 / sh:69-75 — build one context's report block into `text`.
///   `funcs_assoc`/`tags_assoc` are the pair of associative arrays
///   (`help_funcs`+`help_tags` for tags, `help_sfuncs`+`help_styles`
///   for styles); `label` is the per-context heading.
fn append_context_report(
    text: &mut String,
    funcs_assoc: &str,
    tags_assoc: &str,
    heading: impl Fn(&str) -> String,
) {
    // sh:55 / sh:68 — for i in "${(@ok)help_funcs}"; do
    for i in assoc_keys_sorted(funcs_assoc) {
        // sh:56 — text+=$'\n'"tags in context :completion:${i}:"
        text.push('\n');
        text.push_str(&heading(&i));
        // sh:57 — tmp=()
        let mut tmp: Vec<String> = Vec::new();
        // sh:58 — for j in "${(@ps.\0.)help_funcs[$i][2,-1]}"; do
        //   value is "\0f1\0f2…"; [2,-1] drops the leading NUL, then
        //   split on NUL.
        let funcs_val = assoc_get(funcs_assoc, &i);
        for j in nul_split_from_2(&funcs_val) {
            // sh:59 — tmp+=( "${(@s.,.)help_tags[${i}${j}][2,-1]}" )
            //   value is ",seg1,seg2…"; [2,-1] drops the leading comma,
            //   then split on comma.
            let tags_val = assoc_get(tags_assoc, &format!("{}{}", i, j));
            tmp.extend(comma_split_from_2(&tags_val));
        }
        // sh:60 — zformat -a tmp '  (' "$tmp[@]"
        let aligned = zformat_align("  (", &tmp);
        // sh:61 — tmp=( $'\n    '${^tmp}')' )
        let wrapped: Vec<String> = aligned.iter().map(|e| format!("\n    {})", e)).collect();
        // sh:62 — text+="${tmp}"  (array joined by IFS space)
        text.push_str(&wrapped.join(" "));
    }
}

/// `${str[2,-1]}` then `${(ps.\0.)…}` — drop the first char, split on NUL.
fn nul_split_from_2(s: &str) -> Vec<String> {
    let rest: String = s.chars().skip(1).collect();
    if rest.is_empty() {
        return Vec::new();
    }
    rest.split('\0').map(|x| x.to_string()).collect()
}

/// `${str[2,-1]}` then `${(s.,.)…}` — drop the first char, split on comma.
fn comma_split_from_2(s: &str) -> Vec<String> {
    let rest: String = s.chars().skip(1).collect();
    if rest.is_empty() {
        return Vec::new();
    }
    rest.split(',').map(|x| x.to_string()).collect()
}

/// sh:60 — `zformat -a <array> <sep> <specs…>` via the real
///   `bin_zformat` align mode; returns the aligned array.
fn zformat_align(sep: &str, specs: &[String]) -> Vec<String> {
    if specs.is_empty() {
        return Vec::new();
    }
    let tmp_name = ".complete_help.zf";
    let mut argv = vec!["-a".to_string(), tmp_name.to_string(), sep.to_string()];
    argv.extend(specs.iter().cloned());
    let _ = setaparam(tmp_name, Vec::new());
    let _ = bin_zformat("zformat", &argv, &make_ops(), 0);
    let out = getaparam(tmp_name).unwrap_or_default();
    let _ = setaparam(tmp_name, Vec::new());
    out
}

/// `_complete_help` — diagnostic widget. Optional `$1` selects the
/// inner completer (default `_main_complete`).
pub fn _complete_help(args: &[String]) -> i32 {
    // sh:5 — eval "$_comp_setup". The `$_comp_setup` snapshot is
    //   installed and evaluated by the completion entry harness (as the
    //   sibling `_complete_debug` widget also relies on); nothing to do
    //   here.

    // sh:7-8 — local _sort_tags=_help_sort_tags text …; typeset -A
    //   help_funcs help_tags help_sfuncs help_styles. These are
    //   function-local upstream; emulate the dynamic scope with global
    //   params, cleared at entry so a re-invocation starts fresh.
    for a in ["help_funcs", "help_tags", "help_sfuncs", "help_styles"] {
        let _ = setaparam(a, Vec::new());
    }
    // sh:10-11 — publish the scan/filter sets for `_help_sort_tags`.
    let _ = setsparam("_help_scan_funcstack", HELP_SCAN_FUNCSTACK);
    let _ = setsparam("_help_filter_funcstack", HELP_FILTER_FUNCSTACK);
    // sh:7 — _sort_tags=_help_sort_tags. Save the prior value so the
    //   hidden-local semantics don't leak past this widget.
    let saved_sort_tags = getsparam("_sort_tags");
    let _ = setsparam("_sort_tags", "_help_sort_tags");

    // sh:13-16 — `_shadow` compadd/compcall/zstyle (the upstream inline
    //   `compadd(){…}` / `zstyle(){…}` overrides map onto the shfunctab
    //   shadow substrate). See module-level notes: builtin dispatch
    //   bypasses these, so the capture they perform is not reached.
    let _ = dispatch_function_call(
        "_shadow",
        &[
            "compadd".to_string(),
            "compcall".to_string(),
            "zstyle".to_string(),
        ],
    );
    // sh:13-15 — install the override shell functions. `_shadow` (above)
    // backed up the real builtins as `NAME@suffix` and bumped
    // `.shadow.depth`; these overrides are what the `bin_compadd` gap-#3
    // interception hook now routes to under the active shadow. `compadd`
    // returns 1 (suppress real matches during the diagnostic scan); the tag
    // recording happens via `$_sort_tags=_help_sort_tags` set above.
    // (`zstyle`'s recording override — sh:16 — needs builtin-side zstyle
    // interception too and is left to the shadow backup; the styles
    // sub-report stays limited, as documented in the module header.)
    crate::ported::modules::parameter::setfunction("compadd", "return 1".to_string(), 0);
    crate::ported::modules::parameter::setfunction(
        "compcall",
        "_help_sort_tags use-compctl".to_string(),
        0,
    );

    // sh:50 — ${1:-_main_complete}
    let target = args
        .first()
        .filter(|s| !s.is_empty())
        .cloned()
        .unwrap_or_else(|| "_main_complete".to_string());
    let ret = dispatch_function_call(&target, &[]).unwrap_or(1);

    // sh:52 — `unfunction compadd compcall zstyle` (remove the overrides we
    // installed) then sh:53 `_unshadow` (restore the real builtins' backups).
    if let Ok(mut tab) = crate::ported::hashtable::shfunctab_lock().write() {
        tab.remove("compadd");
        tab.remove("compcall");
    }
    let _ = dispatch_function_call("_unshadow", &[]);

    // sh:55-64 — tags report.
    let mut text = String::new();
    append_context_report(&mut text, "help_funcs", "help_tags", |i| {
        format!("tags in context :completion:{}:", i)
    });

    // sh:66-77 — styles report, only for a non-1 numeric argument.
    let numeric: i64 = getsparam("NUMERIC")
        .filter(|s| !s.is_empty())
        .and_then(|s| s.parse().ok())
        .unwrap_or(1);
    if numeric != 1 {
        // sh:67 — text+=$'\n'
        text.push('\n');
        append_context_report(&mut text, "help_sfuncs", "help_styles", |i| {
            format!("styles in context {}", i)
        });
    }

    // sh:78-79 — compstate[list]='list force'; compstate[insert]=''
    set_compstate_str("list", "list force");
    set_compstate_str("insert", "");

    // sh:80 — compadd -UX "$text[2,-1]" -n ''
    //   `$text[2,-1]` drops the leading newline accumulated by the
    //   report loops.
    let body: String = text.chars().skip(1).collect();
    let _ = bin_compadd(
        "compadd",
        &[
            "-U".to_string(),
            "-X".to_string(),
            body,
            "-n".to_string(),
            "".to_string(),
        ],
        &make_ops(),
        0,
    );

    // Restore the hidden-local `_sort_tags`.
    match saved_sort_tags {
        Some(v) => {
            let _ = setsparam("_sort_tags", &v);
        }
        None => {
            let _ = setsparam("_sort_tags", "");
        }
    }

    ret
}

/// sh:83-93 — `_help_sort_tags`. Installed as `$_sort_tags` so
/// `_tags` invokes it for each tag registration; records the
/// responsible completion function (`$f`, derived from `$funcstack`)
/// into `help_funcs`/`help_tags`, then forwards to `comptry` so normal
/// completion still proceeds.
pub fn _help_sort_tags(args: &[String]) -> i32 {
    // sh:84 — f="${${(@)${(@)funcstack[3,(i)_($~_help_scan_funcstack)]}
    //           :#(_($~_help_filter_funcstack)|\((eval|anon)\))}% *}"
    let f = derive_responsible_func();

    // sh:86 — curcontext key.
    let curcontext = getsparam("curcontext").unwrap_or_default();
    // sh:85 — ${argv} joined with space (scalar use).
    let argv_joined = args.join(" ");

    // sh:86-87 — condition:
    //   help_funcs[$curcontext] != *${f}*  ||
    //   help_tags[${curcontext}${f}] != *(${(j:|:)~argv})*
    let funcs_val = assoc_get("help_funcs", &curcontext);
    let tags_key = format!("{}{}", curcontext, f);
    let tags_val = assoc_get("help_tags", &tags_key);

    let f_recorded = funcs_val.contains(&f);
    // `*(t1|t2|…)*` — true when any tag already appears in tags_val.
    let any_tag_present = !args.is_empty() && args.iter().any(|t| tags_val.contains(t.as_str()));

    if !f_recorded || !any_tag_present {
        // sh:88-89 — [[ … != *${f}* ]] && help_funcs[$curcontext]+=$'\0'"${f}"
        if !f_recorded {
            assoc_set("help_funcs", &curcontext, &format!("{}\0{}", funcs_val, f));
        }
        // sh:90 — help_tags[${curcontext}${f}]+=",${argv}:${f}"
        assoc_set(
            "help_tags",
            &tags_key,
            &format!("{},{}:{}", tags_val, argv_joined, f),
        );
        // sh:91 — comptry "$@" 2>/dev/null
        return bin_comptry("comptry", args, &make_ops(), 0);
    }
    0
}

/// `$funcstack` — the shell special is computed from the canonical
/// `FUNCSTACK` Vec (a direct `getaparam` read misses it), innermost
/// frame first, matching `Src/Modules/parameter.c`'s `funcstackgetfn`
/// (mirrored in `subst.rs`). During a real completion the dispatched
/// compsys functions run inside `doshfunc`, so `_help_sort_tags` and
/// `_tags` are the top two frames — exactly what the `[3,…]` slice
/// skips.
fn read_funcstack() -> Vec<String> {
    crate::ported::modules::parameter::FUNCSTACK
        .lock()
        .map(|f| f.iter().rev().map(|fs| fs.name.clone()).collect())
        .unwrap_or_default()
}

/// sh:84 — derive `$f`, the completion function responsible for the
/// current tag registration, from `$funcstack`.
fn derive_responsible_func() -> String {
    let funcstack = read_funcstack();
    let len = funcstack.len();

    // `funcstack[3,(i)_($~_help_scan_funcstack)]`: 1-based slice from
    //   index 3 up to (and including) the first element matching
    //   `_(main_complete|complete|approximate|normal)`.
    let scan: Vec<String> = HELP_SCAN_FUNCSTACK
        .split('|')
        .map(|s| format!("_{}", s))
        .collect();
    // 1-based index of first scan match, or len+1 when none.
    let mut end_1based = len + 1;
    for (idx, el) in funcstack.iter().enumerate() {
        if scan.iter().any(|s| s == el) {
            end_1based = idx + 1;
            break;
        }
    }
    // 1-based [3, end] → rust [2, end).
    let start = 2usize;
    let end = end_1based.min(len);
    let slice: &[String] = if start < end {
        &funcstack[start..end]
    } else {
        &[]
    };

    // `:#(_($~_help_filter_funcstack)|\((eval|anon)\))` — drop filtered
    //   completion helpers and eval/anon frames.
    let filter: Vec<String> = HELP_FILTER_FUNCSTACK
        .split('|')
        .map(|s| format!("_{}", s))
        .collect();
    let kept: Vec<String> = slice
        .iter()
        .filter(|el| {
            let e = el.as_str();
            !(filter.iter().any(|f| f == e) || e == "(eval)" || e == "(anon)")
        })
        // `% *` — strip a trailing " <suffix>" (from the last space).
        .map(|el| match el.rfind(' ') {
            Some(pos) => el[..pos].to_string(),
            None => el.clone(),
        })
        .collect();

    // Outer `${(@)…}` assigned to a scalar → joined with a space.
    kept.join(" ")
}

#[cfg(test)]
mod tests {
    use super::*;

    /// Seed `FUNCSTACK` so `$funcstack` (innermost-first) equals
    /// `names`. `FUNCSTACK` stores push-order (oldest first) and is
    /// reversed on read, so push the reverse here.
    fn set_test_funcstack(names_innermost_first: &[&str]) {
        let mut stack = crate::ported::modules::parameter::FUNCSTACK.lock().unwrap();
        stack.clear();
        for name in names_innermost_first.iter().rev() {
            stack.push(crate::ported::zsh_h::funcstack {
                prev: None,
                name: name.to_string(),
                filename: None,
                caller: None,
                flineno: 0,
                lineno: 0,
                tp: 0,
            });
        }
    }

    fn clear_test_funcstack() {
        crate::ported::modules::parameter::FUNCSTACK
            .lock()
            .unwrap()
            .clear();
    }

    #[test]
    fn returns_one_without_executor() {
        let _g = crate::test_util::global_state_lock();
        assert_eq!(_complete_help(&[]), 1);
    }

    #[test]
    fn clears_help_assocs_before_dispatch() {
        // sh:8 — the four `typeset -A` assocs are function-local
        //   upstream; here they are cleared at entry so stale entries
        //   from a prior invocation never bleed into a fresh report.
        let _g = crate::test_util::global_state_lock();
        let _ = setaparam("help_funcs", vec!["ctx".to_string(), "\0stale".to_string()]);
        let _ = _complete_help(&[]);
        let after = getaparam("help_funcs").unwrap_or_default();
        assert!(
            !after.iter().any(|s| s == "\0stale"),
            "help_funcs must be cleared at widget entry"
        );
    }

    #[test]
    fn sets_sort_tags_hook_during_run_and_restores_after() {
        // sh:7 — `_sort_tags=_help_sort_tags` is the mechanism by which
        //   `_tags` routes tag registrations into the report. It is a
        //   hidden local upstream, so it must not survive the widget.
        let _g = crate::test_util::global_state_lock();
        let _ = setsparam("_sort_tags", "");
        let _ = _complete_help(&[]);
        assert_eq!(
            getsparam("_sort_tags").unwrap_or_default(),
            "",
            "_sort_tags must be restored to its prior (empty) value"
        );
    }

    #[test]
    fn help_sort_tags_records_func_and_tags() {
        // sh:84-91 — with a curcontext and a funcstack naming a
        //   completer, `_help_sort_tags` records the function into
        //   help_funcs and the tag list into help_tags.
        let _g = crate::test_util::global_state_lock();
        let _ = setaparam("help_funcs", Vec::new());
        let _ = setaparam("help_tags", Vec::new());
        let _ = setsparam("curcontext", ":completion::complete:mycmd:");
        // funcstack: [ _help_sort_tags, _tags, _files, _main_complete ]
        //   → slice[3,(i)_main_complete] = (_files _main_complete),
        //   filtered → "_files _main_complete" joined.
        set_test_funcstack(&["_help_sort_tags", "_tags", "_files", "_main_complete"]);
        let _ = _help_sort_tags(&["files".to_string(), "directories".to_string()]);
        let funcs = assoc_get("help_funcs", ":completion::complete:mycmd:");
        assert!(
            funcs.contains("_files"),
            "help_funcs must record the responsible completer, got {:?}",
            funcs
        );
        let tags = assoc_get(
            "help_tags",
            &format!(":completion::complete:mycmd:{}", "_files _main_complete"),
        );
        assert!(
            tags.contains("files directories"),
            "help_tags must record the tag list, got {:?}",
            tags
        );
        clear_test_funcstack();
    }

    #[test]
    fn derive_responsible_func_slices_and_filters() {
        // sh:84 — filter set drops `_dispatch`/`_wanted`; scan set
        //   terminates the slice at `_main_complete`.
        let _g = crate::test_util::global_state_lock();
        set_test_funcstack(&[
            "_help_sort_tags",
            "_tags",
            "_wanted",
            "_files",
            "_main_complete",
            "_normal",
        ]);
        let f = derive_responsible_func();
        assert_eq!(f, "_files _main_complete");
        clear_test_funcstack();
    }
}