kata 0.12.0

//! Var resolution with provenance.
//!
//! Precedence chain (lower-indexed wins):
//!
//!   CLI (`--var name=val`) > env (`KATA_VAR_<name>`) >
//!   `.kata/vars.toml` > applied.toml > preset.vars >
//!   template-side `vars.toml` seed > manifest.default > prompt
//!
//! `prompt` only fires when `interactive == true`; otherwise a
//! missing-required-without-default var is an error.
//!
//! Resolution returns both the resolved values AND a per-key
//! provenance map (`VarSource`) so callers can act differently on
//! "the user typed this" (Cli/Env/Prompt) vs "the template shipped
//! this" (VarsFile/Preset/TemplateSeed/Default). The runner uses
//! that to keep `applied.toml.vars` free of values that already
//! live in a tracked file — see yukimemi/kata#58.

use std::collections::BTreeMap;

use camino::Utf8Path;

use crate::error::{Error, Result};
use crate::manifest::VarSpec;

const ENV_PREFIX: &str = "KATA_VAR_";

/// Directory inside a PJ that holds kata-managed bookkeeping plus
/// any consumer-owned `vars*.toml` files. See [`matches_vars_pattern`]
/// for the file-name rule used to pick everything that contributes.
pub(crate) const KATA_DIR_REL: &str = ".kata";

/// Recognise both the historic single-file form (`.kata/vars.toml`)
/// and the layered form (`.kata/vars.<layer>.toml`) introduced in
/// #86. `vars.toml` is treated as one of the matched files; the
/// caller sorts the list alphabetically before merging.
pub(crate) fn matches_vars_pattern(name: &str) -> bool {
    if name == "vars.toml" {
        return true;
    }
    // `vars.<something>.toml` — non-empty middle segment, no
    // trailing dot. `vars..toml` is rejected (would be a typo).
    let Some(rest) = name.strip_prefix("vars.") else {
        return false;
    };
    let Some(middle) = rest.strip_suffix(".toml") else {
        return false;
    };
    !middle.is_empty() && !middle.starts_with('.')
}

/// Where a resolved var came from. Used downstream by the runner to
/// decide which vars to persist in `applied.toml.vars` (only the
/// "user-typed" sources — see yukimemi/kata#58).
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum VarSource {
    /// `--var name=val` from the command line.
    Cli,
    /// `KATA_VAR_<name>` from the environment.
    Env,
    /// `<pj_root>/.kata/vars.toml`.
    VarsFile,
    /// `applied.toml.vars` from a previous apply.
    Applied,
    /// Preset file vars.
    Preset,
    /// The `vars.toml` source file declared by a template via
    /// `[[file]] dst = ".kata/vars.toml"`. Auto-loaded so the
    /// renderer sees the seeded values on the **first** apply,
    /// before kata writes the seed to disk (yukimemi/kata#53).
    TemplateSeed,
    /// `[vars] default = …` in a template manifest.
    Default,
    /// User answered an interactive prompt during this apply.
    Prompt,
}

impl VarSource {
    /// Returns `true` when the resolved value should be re-recorded
    /// in `applied.toml.vars`. The persist set is "values whose only
    /// other home is the user's memory" — i.e. user-typed inputs
    /// (Cli / Env / Prompt) AND the carry-forward of those from a
    /// previous apply (Applied itself). Without persisting `Applied`,
    /// a one-shot `--var foo=bar` on run 1 would survive run 2 (still
    /// in applied) but vanish on run 3 (run 2 wrote nothing because
    /// the source was now `Applied`, not `Cli`).
    ///
    /// Returns `false` for sources that already live in a tracked
    /// file (VarsFile / Preset / TemplateSeed) or regenerate every
    /// apply (Default) — duplicating them in applied.toml bloats the
    /// file and conflates kata's implicit memory with consumer-owned
    /// configuration.
    pub fn should_persist_in_applied(self) -> bool {
        matches!(
            self,
            VarSource::Cli | VarSource::Env | VarSource::Prompt | VarSource::Applied
        )
    }
}

/// Collect inputs from each precedence layer. Lower indices in this
/// struct correspond to higher precedence.
#[derive(Debug, Clone, Default)]
pub struct VarSources {
    /// `--var name=val` from the command line.
    pub cli: BTreeMap<String, toml::Value>,
    /// `KATA_VAR_<name>` env vars (collected at runtime). Always
    /// strings.
    pub env: BTreeMap<String, toml::Value>,
    /// Values from the PJ-owned `.kata/vars.toml`. Consumer-managed
    /// (kata never writes here) — Renovate or hand edits flow into
    /// the next `kata apply` without revert.
    pub vars_file: toml::Table,
    /// Values previously recorded by kata in `applied.toml`.
    pub applied: toml::Table,
    /// Values supplied by a preset file.
    pub preset: toml::Table,
    /// Template-side `vars.toml` content (the source of any
    /// `[[file]]` declaration with `dst = ".kata/vars.toml"`).
    /// Auto-merged from every template in compose order — see
    /// `VarSources::load_template_seed`.
    pub template_seed: toml::Table,
}

impl VarSources {
    /// Read every `KATA_VAR_<name>` env var into a fresh table.
    /// The name suffix is preserved verbatim — Tera (and our manifest
    /// `[vars]` table) is case-sensitive, so lowercasing here would
    /// silently break templates that declare e.g. `MyVar`.
    pub fn from_env() -> BTreeMap<String, toml::Value> {
        let mut out = BTreeMap::new();
        for (k, v) in std::env::vars_os() {
            let Ok(k) = k.into_string() else { continue };
            let Ok(v) = v.into_string() else { continue };
            if let Some(name) = k.strip_prefix(ENV_PREFIX) {
                out.insert(name.to_string(), toml::Value::String(v));
            }
        }
        out
    }

    /// Discover every `<pj_root>/.kata/vars*.toml` and deep-merge
    /// them into one table. Each layer's `vars.<name>.toml` (#86)
    /// is read independently; `vars.toml` keeps the historic
    /// single-file role.
    ///
    /// Discovery + merge order: every `vars.<name>.toml` first in
    /// alphabetical order, then `vars.toml` last. Putting the
    /// bare base file last guarantees its deep-merge runs after
    /// every layered file and therefore wins on any leaf-key
    /// conflict — that's the historic single-file pinning
    /// semantic preserved across the layered form. Plain
    /// alphabetical sort can't do this on its own because the
    /// ordering between `vars.toml` and `vars.<X>.toml` flips on
    /// whether the layer-name's first char is below or above 't'
    /// (`vars.react.toml` < `vars.toml` < `vars.web.toml`), so an
    /// explicit "vars.toml goes last" rule is required.
    ///
    /// Missing `.kata` directory is not an error (vars.toml is
    /// opt-in). A present-but-malformed file is a hard error so
    /// the consumer notices their typo before it silently degrades
    /// to defaults.
    pub fn load_vars_file(pj_root: &Utf8Path) -> Result<toml::Table> {
        let kata_dir = pj_root.join(KATA_DIR_REL);
        let entries = match std::fs::read_dir(kata_dir.as_std_path()) {
            Ok(rd) => rd,
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => {
                return Ok(toml::Table::new());
            }
            Err(e) => return Err(Error::io_at(kata_dir.as_std_path(), e)),
        };
        let mut paths: Vec<std::path::PathBuf> = Vec::new();
        for entry in entries {
            let entry = entry.map_err(|e| Error::io_at(kata_dir.as_std_path(), e))?;
            let path = entry.path();
            let Some(name) = path.file_name().and_then(|n| n.to_str()) else {
                continue;
            };
            if matches_vars_pattern(name) {
                paths.push(path);
            }
        }
        // Custom sort: every `vars.<X>.toml` alphabetically, then
        // `vars.toml` last so the bare base file wins on a leaf-key
        // conflict regardless of layer-name first letter (see doc
        // above).
        paths.sort_by(|a, b| {
            let name_a = a.file_name().and_then(|n| n.to_str()).unwrap_or("");
            let name_b = b.file_name().and_then(|n| n.to_str()).unwrap_or("");
            match (name_a == "vars.toml", name_b == "vars.toml") {
                (true, true) => std::cmp::Ordering::Equal,
                (true, false) => std::cmp::Ordering::Greater,
                (false, true) => std::cmp::Ordering::Less,
                (false, false) => name_a.cmp(name_b),
            }
        });

        let mut merged = toml::Table::new();
        for path in paths {
            let content =
                std::fs::read_to_string(&path).map_err(|e| Error::io_at(path.as_path(), e))?;
            let parsed: toml::Table = toml::from_str(&content)
                .map_err(|e| Error::Config(format!("parse {}: {e}", path.display())))?;
            deep_merge_table(&mut merged, parsed);
        }
        Ok(merged)
    }

    /// Look up `key` in every source layer and return the values
    /// in **low → high precedence order**. The single hard-coded
    /// chain lives here so callers (e.g. `VarResolver::resolve_one`)
    /// don't drift away from canonical precedence when a new
    /// source is added; adding a field to `VarSources` means
    /// extending this method in one place and every consumer
    /// picks up the new layer at the right slot.
    ///
    /// Each entry is `(Option<&toml::Value>, VarSource)`; sources
    /// that don't carry the key contribute `None` so a deep-merge
    /// caller can skip them with a single `?` / `let-else`.
    pub fn get_in_precedence_order(&self, key: &str) -> Vec<(Option<&toml::Value>, VarSource)> {
        vec![
            (self.template_seed.get(key), VarSource::TemplateSeed),
            (self.preset.get(key), VarSource::Preset),
            (self.applied.get(key), VarSource::Applied),
            (self.vars_file.get(key), VarSource::VarsFile),
            (self.env.get(key), VarSource::Env),
            (self.cli.get(key), VarSource::Cli),
        ]
    }
}

/// Deep-merge `src` into `dst` (used to combine each template's
/// `vars.toml` seed in compose order). Tables merge key-by-key
/// recursively; non-table values get replaced wholesale (later wins).
pub fn deep_merge_table(dst: &mut toml::Table, src: toml::Table) {
    for (k, v) in src {
        match (dst.get_mut(&k), v) {
            (Some(toml::Value::Table(dst_t)), toml::Value::Table(src_t)) => {
                deep_merge_table(dst_t, src_t);
            }
            (_, v) => {
                dst.insert(k, v);
            }
        }
    }
}

/// Output of [`VarResolver::resolve`] — both the flat values table
/// (for Tera context construction) and the per-key provenance map
/// (for the runner's `applied.toml` filter).
#[derive(Debug, Clone, Default)]
pub struct ResolvedVars {
    pub values: toml::Table,
    pub sources: BTreeMap<String, VarSource>,
}

/// Resolves vars by combining sources + manifest specs, optionally
/// prompting for missing values via a user-provided closure.
pub struct VarResolver<'a, F> {
    pub specs: &'a BTreeMap<String, VarSpec>,
    pub sources: &'a VarSources,
    pub interactive: bool,
    /// Called when the resolver needs to ask the user. Returns the
    /// user's answer as a `toml::Value`. Implementations live outside
    /// this module (see `interactive::prompt_var`).
    pub prompter: F,
}

impl<'a, F> VarResolver<'a, F>
where
    F: FnMut(&str, &VarSpec) -> Result<toml::Value>,
{
    pub fn resolve(mut self) -> Result<ResolvedVars> {
        let mut out = ResolvedVars::default();

        // 1) Start from the union of declared spec keys and any keys
        //    that appear in source layers (so callers can pass through
        //    extra vars not declared in the manifest).
        let mut keys: BTreeMap<String, ()> = BTreeMap::new();
        for k in self.specs.keys() {
            keys.insert(k.clone(), ());
        }
        for k in self.sources.cli.keys() {
            keys.insert(k.clone(), ());
        }
        for k in self.sources.env.keys() {
            keys.insert(k.clone(), ());
        }
        for k in self.sources.vars_file.keys() {
            keys.insert(k.clone(), ());
        }
        for k in self.sources.applied.keys() {
            keys.insert(k.clone(), ());
        }
        for k in self.sources.preset.keys() {
            keys.insert(k.clone(), ());
        }
        for k in self.sources.template_seed.keys() {
            keys.insert(k.clone(), ());
        }

        for (key, _) in keys {
            let spec = self.specs.get(&key);
            if let Some((value, source)) = self.resolve_one(&key, spec)? {
                out.values.insert(key.clone(), value);
                out.sources.insert(key, source);
            }
        }

        Ok(out)
    }

    fn resolve_one(
        &mut self,
        key: &str,
        spec: Option<&VarSpec>,
    ) -> Result<Option<(toml::Value, VarSource)>> {
        // Walk sources low → high precedence, accumulating into
        // `merged`. For scalar / array values the higher source
        // simply overwrites the lower one (the historic behaviour
        // — single-source provenance). For TABLE values we
        // deep-merge so a partial top-level table in one source
        // (e.g. `.kata/vars.toml` carrying only the pj-base layer
        // of `[actions]`) doesn't shadow keys the lower-precedence
        // layers (template seeds) contribute.
        //
        // Without this, `[actions]` in `.kata/vars.toml` containing
        // only `{checkout, create_pull_request}` would wipe out the
        // pj-rust template seed's `swatinem_rust_cache` and break
        // the ci.yml.tera render — see the bug surfaced when an
        // old kata wrote a partial vars.toml then a newer kata
        // tried to re-apply on top of it.
        //
        // The recorded `VarSource` is whichever source contributed
        // the *highest-precedence* layer of the merged value — the
        // applied.toml-vars filter then sees the merged value as
        // "owned by VarsFile / Env / etc." and persists or skips
        // it the same way it did before.
        //
        // The precedence chain itself lives on `VarSources` so a
        // new source field is picked up here without touching this
        // method (Gemini, #100 review).
        let mut merged: Option<toml::Value> = None;
        let mut highest: Option<VarSource> = None;
        for (val_opt, source) in self.sources.get_in_precedence_order(key) {
            let Some(val) = val_opt else { continue };
            highest = Some(source);
            // The clone here is unavoidable while we accumulate
            // into an owned `toml::Value` — `toml::Value::Table`
            // owns its underlying `Table`, so even a
            // `&Table -> Table` deep merge has to copy the leaf
            // values anyway. Deferring the clone to the table
            // arm (the only one that needs structural access)
            // doesn't reduce the work, just shuffles where the
            // copy happens (see #100 review).
            merged = Some(match (merged.take(), val.clone()) {
                (None, new) => new,
                (Some(toml::Value::Table(mut acc)), toml::Value::Table(new_t)) => {
                    // `deep_merge_table(dst, src)` lets `src` win
                    // on leaf conflicts, which matches our "higher
                    // source overwrites lower" rule (the loop's
                    // current iteration is the higher one).
                    deep_merge_table(&mut acc, new_t);
                    toml::Value::Table(acc)
                }
                (Some(_), new) => {
                    // Scalar / array (or shape change): higher
                    // source replaces lower wholesale.
                    new
                }
            });
        }
        if let Some(value) = merged {
            return Ok(Some((
                value,
                highest.expect("highest set whenever merged is"),
            )));
        }

        // 7) manifest default
        let spec = match spec {
            Some(s) => s,
            None => return Ok(None),
        };
        if let Some(v) = &spec.default {
            return Ok(Some((v.clone(), VarSource::Default)));
        }
        // 8) prompt (or error if non-interactive)
        if self.interactive {
            let v = (self.prompter)(key, spec)?;
            return Ok(Some((v, VarSource::Prompt)));
        }
        if spec.required {
            return Err(Error::Config(format!(
                "var `{key}` is required but not provided (cli/env/.kata/vars.toml/applied/preset/template-seed/default all empty)"
            )));
        }
        Ok(None)
    }
}

/// Parse a `name=value` CLI argument into a typed `toml::Value`.
/// Numbers and booleans are detected; everything else is a string.
pub fn parse_cli_var(s: &str) -> Result<(String, toml::Value)> {
    let (k, v) = s
        .split_once('=')
        .ok_or_else(|| Error::Config(format!("--var expects `name=value`, got {s:?}")))?;
    let k = k.trim().to_string();
    let v = v.trim();
    if k.is_empty() {
        return Err(Error::Config(format!("--var has empty name in {s:?}")));
    }
    let parsed: toml::Value = if v == "true" {
        toml::Value::Boolean(true)
    } else if v == "false" {
        toml::Value::Boolean(false)
    } else if let Ok(n) = v.parse::<i64>() {
        toml::Value::Integer(n)
    } else if let Ok(n) = v.parse::<f64>() {
        toml::Value::Float(n)
    } else {
        toml::Value::String(v.to_string())
    };
    Ok((k, parsed))
}

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

    fn never_prompt(_: &str, _: &VarSpec) -> Result<toml::Value> {
        panic!("prompt should not have been called");
    }

    fn spec_with_default(default: &str) -> BTreeMap<String, VarSpec> {
        BTreeMap::from([(
            "k".to_string(),
            VarSpec {
                prompt: None,
                default: Some(toml::Value::String(default.into())),
                required: false,
                choices: None,
                pattern: None,
                secret: false,
            },
        )])
    }

    #[test]
    fn cli_wins_over_every_other_source() {
        let specs = spec_with_default("from-default");
        let sources = VarSources {
            cli: BTreeMap::from([("k".to_string(), toml::Value::String("from-cli".into()))]),
            env: BTreeMap::from([("k".to_string(), toml::Value::String("from-env".into()))]),
            vars_file: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-vars-file".into()),
            )]),
            applied: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-applied".into()),
            )]),
            preset: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-preset".into()),
            )]),
            template_seed: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-template-seed".into()),
            )]),
        };
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let out = r.resolve().unwrap();
        assert_eq!(out.values["k"].as_str(), Some("from-cli"));
        assert_eq!(out.sources["k"], VarSource::Cli);
    }

    fn table(entries: &[(&str, &str)]) -> toml::Value {
        toml::Value::Table(toml::Table::from_iter(
            entries
                .iter()
                .map(|(k, v)| (k.to_string(), toml::Value::String((*v).to_string()))),
        ))
    }

    #[test]
    fn partial_table_in_vars_file_does_not_shadow_template_seed_siblings() {
        // Repro for the bug surfaced when an older kata wrote a
        // partial `.kata/vars.toml` (only pj-base's actions like
        // `checkout`) and a newer kata tried to re-apply on top of
        // it. Without per-key Table deep-merge, the partial vars
        // file's `[actions]` table fully replaced the template
        // seed's `[actions]`, wiping out the pj-rust seed's
        // `swatinem_rust_cache` and breaking ci.yml.tera render.
        //
        // The resolver should now deep-merge tables across sources,
        // so the merged `actions` table contains every key any
        // source ships, with higher-precedence sources winning on
        // leaf conflicts.
        let specs = BTreeMap::new();
        let sources = VarSources {
            // Higher precedence — pj-base layer only.
            vars_file: toml::Table::from_iter([(
                "actions".to_string(),
                table(&[("checkout", "v6.0.2"), ("create_pull_request", "v8")]),
            )]),
            // Lower precedence — pj-base + pj-rust template seed
            // contributions deep-merged before resolve runs.
            template_seed: toml::Table::from_iter([(
                "actions".to_string(),
                table(&[
                    ("checkout", "v6"),
                    ("create_pull_request", "v7"),
                    ("swatinem_rust_cache", "v2"),
                ]),
            )]),
            ..Default::default()
        };
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let out = r.resolve().unwrap();
        let actions = out.values["actions"].as_table().expect("table");
        // High-precedence (vars_file) keys win on leaf conflict.
        assert_eq!(actions["checkout"].as_str(), Some("v6.0.2"));
        assert_eq!(actions["create_pull_request"].as_str(), Some("v8"));
        // Lower-precedence keys (only in template_seed) survive —
        // this is the bug fix.
        assert_eq!(
            actions["swatinem_rust_cache"].as_str(),
            Some("v2"),
            "template_seed's swatinem_rust_cache must survive a partial vars_file overlay",
        );
        // Provenance points at the highest-precedence layer that
        // contributed (vars_file here).
        assert_eq!(out.sources["actions"], VarSource::VarsFile);
    }

    #[test]
    fn scalar_in_higher_source_still_overrides_table_in_lower() {
        // Shape change across precedence layers stays a wholesale
        // replacement: if a higher source ships a scalar while a
        // lower source ships a table at the same key, the higher
        // wins. (Same behaviour as before the deep-merge change —
        // only Table+Table pairs deep-merge.)
        let specs = BTreeMap::new();
        let sources = VarSources {
            vars_file: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("scalar-wins".into()),
            )]),
            template_seed: toml::Table::from_iter([(
                "k".to_string(),
                table(&[("nested", "from-seed")]),
            )]),
            ..Default::default()
        };
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let out = r.resolve().unwrap();
        assert_eq!(out.values["k"].as_str(), Some("scalar-wins"));
    }

    #[test]
    fn vars_file_wins_over_applied_preset_template_seed_default() {
        let specs = spec_with_default("from-default");
        let sources = VarSources {
            vars_file: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-vars-file".into()),
            )]),
            applied: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-applied".into()),
            )]),
            preset: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-preset".into()),
            )]),
            template_seed: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-template-seed".into()),
            )]),
            ..Default::default()
        };
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let out = r.resolve().unwrap();
        assert_eq!(out.values["k"].as_str(), Some("from-vars-file"));
        assert_eq!(out.sources["k"], VarSource::VarsFile);
    }

    #[test]
    fn template_seed_feeds_renderer_when_no_vars_file_yet() {
        // The yukimemi/kata#53 case: a fresh consumer has no
        // `.kata/vars.toml` yet, so the template-side seed is the only
        // place the renderer can find action versions on the first
        // apply. preset, applied, and CLI/env are all empty.
        let specs = BTreeMap::new();
        let sources = VarSources {
            template_seed: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-template-seed".into()),
            )]),
            ..Default::default()
        };
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let out = r.resolve().unwrap();
        assert_eq!(out.values["k"].as_str(), Some("from-template-seed"));
        assert_eq!(out.sources["k"], VarSource::TemplateSeed);
    }

    #[test]
    fn template_seed_is_below_preset() {
        // If a preset pins a different version than the template ships,
        // the preset wins. Template seed is only the fallback for
        // first-apply rendering — once a preset / vars.toml / applied
        // / CLI / env tracks the value, those take over.
        let specs = BTreeMap::new();
        let sources = VarSources {
            preset: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-preset".into()),
            )]),
            template_seed: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-template-seed".into()),
            )]),
            ..Default::default()
        };
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let out = r.resolve().unwrap();
        assert_eq!(out.values["k"].as_str(), Some("from-preset"));
        assert_eq!(out.sources["k"], VarSource::Preset);
    }

    #[test]
    fn template_seed_above_manifest_default() {
        // Template's seed should beat the manifest's `default = ...`,
        // because seeds carry concrete pins (often action versions)
        // that the template wants to be the actual starting state,
        // not just a fallback.
        let specs = spec_with_default("from-default");
        let sources = VarSources {
            template_seed: toml::Table::from_iter([(
                "k".to_string(),
                toml::Value::String("from-template-seed".into()),
            )]),
            ..Default::default()
        };
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let out = r.resolve().unwrap();
        assert_eq!(out.values["k"].as_str(), Some("from-template-seed"));
        assert_eq!(out.sources["k"], VarSource::TemplateSeed);
    }

    #[test]
    fn provenance_tracks_each_source_correctly() {
        // Multiple keys, each resolved from a different source — make
        // sure the per-key provenance map distinguishes them. Drives
        // the applied-toml-vars filter in the runner.
        let specs = BTreeMap::from([(
            "from_default_key".to_string(),
            VarSpec {
                prompt: None,
                default: Some(toml::Value::String("d".into())),
                required: false,
                choices: None,
                pattern: None,
                secret: false,
            },
        )]);
        let sources = VarSources {
            cli: BTreeMap::from([("cli_key".to_string(), toml::Value::String("c".into()))]),
            env: BTreeMap::from([("env_key".to_string(), toml::Value::String("e".into()))]),
            vars_file: toml::Table::from_iter([(
                "vars_file_key".to_string(),
                toml::Value::String("vf".into()),
            )]),
            applied: toml::Table::from_iter([(
                "applied_key".to_string(),
                toml::Value::String("a".into()),
            )]),
            preset: toml::Table::from_iter([(
                "preset_key".to_string(),
                toml::Value::String("p".into()),
            )]),
            template_seed: toml::Table::from_iter([(
                "template_seed_key".to_string(),
                toml::Value::String("ts".into()),
            )]),
        };
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let out = r.resolve().unwrap();
        assert_eq!(out.sources["cli_key"], VarSource::Cli);
        assert_eq!(out.sources["env_key"], VarSource::Env);
        assert_eq!(out.sources["vars_file_key"], VarSource::VarsFile);
        assert_eq!(out.sources["applied_key"], VarSource::Applied);
        assert_eq!(out.sources["preset_key"], VarSource::Preset);
        assert_eq!(out.sources["template_seed_key"], VarSource::TemplateSeed);
        assert_eq!(out.sources["from_default_key"], VarSource::Default);
    }

    #[test]
    fn should_persist_in_applied_includes_user_typed_and_applied_carry() {
        // The whole point of provenance: applied.toml.vars stays free
        // of values that already live in a tracked source (yukimemi/kata#58).
        // But `Applied` itself MUST persist — it's the carry-forward
        // of a previous CLI/Env/Prompt answer, and dropping it would
        // make those answers survive only one apply.
        assert!(VarSource::Cli.should_persist_in_applied());
        assert!(VarSource::Env.should_persist_in_applied());
        assert!(VarSource::Prompt.should_persist_in_applied());
        assert!(VarSource::Applied.should_persist_in_applied());
        assert!(!VarSource::VarsFile.should_persist_in_applied());
        assert!(!VarSource::Preset.should_persist_in_applied());
        assert!(!VarSource::TemplateSeed.should_persist_in_applied());
        assert!(!VarSource::Default.should_persist_in_applied());
    }

    #[test]
    fn deep_merge_table_combines_nested_keys() {
        let mut dst = toml::Table::new();
        dst.insert(
            "actions".to_string(),
            toml::Value::Table(toml::Table::from_iter([(
                "checkout".to_string(),
                toml::Value::String("v6".into()),
            )])),
        );
        let src = toml::Table::from_iter([(
            "actions".to_string(),
            toml::Value::Table(toml::Table::from_iter([(
                "swatinem_rust_cache".to_string(),
                toml::Value::String("v2".into()),
            )])),
        )]);
        deep_merge_table(&mut dst, src);
        let actions = dst["actions"].as_table().unwrap();
        assert_eq!(actions["checkout"].as_str(), Some("v6"));
        assert_eq!(actions["swatinem_rust_cache"].as_str(), Some("v2"));
    }

    #[test]
    fn deep_merge_table_later_wins_on_leaf_conflict() {
        let mut dst =
            toml::Table::from_iter([("k".to_string(), toml::Value::String("first".into()))]);
        deep_merge_table(
            &mut dst,
            toml::Table::from_iter([("k".to_string(), toml::Value::String("second".into()))]),
        );
        assert_eq!(dst["k"].as_str(), Some("second"));
    }

    #[test]
    fn load_vars_file_returns_empty_when_missing() {
        let tmp = tempfile::tempdir().unwrap();
        let root = camino::Utf8Path::from_path(tmp.path()).unwrap();
        let out = VarSources::load_vars_file(root).unwrap();
        assert!(out.is_empty());
    }

    #[test]
    fn load_vars_file_parses_toml() {
        let tmp = tempfile::tempdir().unwrap();
        let root = camino::Utf8Path::from_path(tmp.path()).unwrap();
        std::fs::create_dir_all(root.join(".kata")).unwrap();
        std::fs::write(
            root.join(".kata/vars.toml"),
            "key = \"value\"\n[group]\nnested = 1\n",
        )
        .unwrap();
        let out = VarSources::load_vars_file(root).unwrap();
        assert_eq!(out["key"].as_str(), Some("value"));
        assert_eq!(out["group"]["nested"].as_integer(), Some(1));
    }

    #[test]
    fn load_vars_file_errors_on_malformed_toml() {
        let tmp = tempfile::tempdir().unwrap();
        let root = camino::Utf8Path::from_path(tmp.path()).unwrap();
        std::fs::create_dir_all(root.join(".kata")).unwrap();
        std::fs::write(root.join(".kata/vars.toml"), "this is = not [valid\n").unwrap();
        let err = VarSources::load_vars_file(root).unwrap_err();
        assert!(matches!(err, Error::Config(_)));
    }

    #[test]
    fn load_vars_file_merges_layered_vars_toml_files() {
        // Issue #86: each template layer ships its own
        // `.kata/vars.<layer>.toml`. The consumer-side loader
        // discovers all of them and deep-merges in alphabetical order.
        let tmp = tempfile::tempdir().unwrap();
        let root = camino::Utf8Path::from_path(tmp.path()).unwrap();
        std::fs::create_dir_all(root.join(".kata")).unwrap();
        // pj-base layer
        std::fs::write(
            root.join(".kata/vars.toml"),
            "[actions]\ncheckout = \"v4\"\n",
        )
        .unwrap();
        // pj-rust layer
        std::fs::write(
            root.join(".kata/vars.rust.toml"),
            "[actions]\nswatinem = \"v2\"\n",
        )
        .unwrap();
        // pj-react layer
        std::fs::write(
            root.join(".kata/vars.react.toml"),
            "[actions]\nsetup_node = \"v4\"\n",
        )
        .unwrap();

        let out = VarSources::load_vars_file(root).unwrap();
        let actions = out["actions"].as_table().expect("actions table");
        assert_eq!(actions["checkout"].as_str(), Some("v4"));
        assert_eq!(actions["swatinem"].as_str(), Some("v2"));
        assert_eq!(actions["setup_node"].as_str(), Some("v4"));
    }

    #[test]
    fn load_vars_file_bare_vars_toml_wins_on_leaf_conflict() {
        // The explicit "vars.toml is sorted last" rule means
        // `vars.<X>.toml` is always merged BEFORE `vars.toml`,
        // regardless of layer-name first letter. On a leaf-key
        // conflict, the bare `vars.toml` therefore wins — which
        // is the historic single-file behaviour for PJs that pin
        // values in the consumer-owned `vars.toml`.
        let tmp = tempfile::tempdir().unwrap();
        let root = camino::Utf8Path::from_path(tmp.path()).unwrap();
        std::fs::create_dir_all(root.join(".kata")).unwrap();
        std::fs::write(
            root.join(".kata/vars.rust.toml"),
            "version = \"layer-rust\"\n",
        )
        .unwrap();
        std::fs::write(
            root.join(".kata/vars.toml"),
            "version = \"consumer-pinned\"\n",
        )
        .unwrap();
        let out = VarSources::load_vars_file(root).unwrap();
        assert_eq!(out["version"].as_str(), Some("consumer-pinned"));
    }

    #[test]
    fn load_vars_file_bare_vars_toml_wins_even_when_layer_name_sorts_after_t() {
        // Regression for the issue gemini-code-assist flagged on
        // PR #93: plain alphabetical sort would put `vars.web.toml`
        // AFTER `vars.toml` (because 'w' > 't'), making the layer
        // overwrite the consumer-pinned base. The custom sort
        // pins `vars.toml` last so the consumer always wins.
        let tmp = tempfile::tempdir().unwrap();
        let root = camino::Utf8Path::from_path(tmp.path()).unwrap();
        std::fs::create_dir_all(root.join(".kata")).unwrap();
        std::fs::write(
            root.join(".kata/vars.web.toml"),
            "version = \"layer-web\"\n",
        )
        .unwrap();
        std::fs::write(
            root.join(".kata/vars.toml"),
            "version = \"consumer-pinned\"\n",
        )
        .unwrap();
        let out = VarSources::load_vars_file(root).unwrap();
        assert_eq!(
            out["version"].as_str(),
            Some("consumer-pinned"),
            "`vars.toml` must win on leaf-key conflict regardless of layer-name first letter",
        );
    }

    #[test]
    fn matches_vars_pattern_rules() {
        assert!(matches_vars_pattern("vars.toml"));
        assert!(matches_vars_pattern("vars.rust.toml"));
        assert!(matches_vars_pattern("vars.x.toml"));
        // Negative cases
        assert!(!matches_vars_pattern("varz.toml"));
        assert!(!matches_vars_pattern("not-vars.toml"));
        assert!(!matches_vars_pattern("vars.tom")); // wrong suffix
        assert!(!matches_vars_pattern("vars..toml")); // empty middle
        assert!(!matches_vars_pattern("vars.toml.bak"));
        assert!(!matches_vars_pattern("vars"));
    }

    #[test]
    fn errors_on_required_missing_non_interactive() {
        let specs = BTreeMap::from([(
            "needed".to_string(),
            VarSpec {
                prompt: None,
                default: None,
                required: true,
                choices: None,
                pattern: None,
                secret: false,
            },
        )]);
        let sources = VarSources::default();
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let err = r.resolve().unwrap_err();
        assert!(matches!(err, Error::Config(_)));
    }

    #[test]
    fn manifest_default_used_when_no_source() {
        let specs = spec_with_default("d");
        let sources = VarSources::default();
        let r = VarResolver {
            specs: &specs,
            sources: &sources,
            interactive: false,
            prompter: never_prompt,
        };
        let out = r.resolve().unwrap();
        assert_eq!(out.values["k"].as_str(), Some("d"));
        assert_eq!(out.sources["k"], VarSource::Default);
    }

    #[test]
    fn parses_cli_var_typed() {
        assert_eq!(
            parse_cli_var("name=foo").unwrap(),
            ("name".into(), toml::Value::String("foo".into()))
        );
        assert_eq!(
            parse_cli_var("count=42").unwrap(),
            ("count".into(), toml::Value::Integer(42))
        );
        assert_eq!(
            parse_cli_var("flag=true").unwrap(),
            ("flag".into(), toml::Value::Boolean(true))
        );
        assert!(parse_cli_var("nope").is_err());
        assert!(parse_cli_var("=val").is_err());
    }
}