pond-db 0.5.1

//! Configuration loading: the `[embeddings]`, `[sources]`, and `[storage]`
//! blocks.
//!
//! pond ships built-in defaults, so an instance with no `config.toml` still
//! works. `pond config --print-schema` emits [`DEFAULT_CONFIG_TOML`], the
//! fully-annotated example.

use std::{
    collections::BTreeMap,
    path::{Path, PathBuf},
};

use anyhow::{Context, Result, anyhow, bail};
use lance_io::object_store::uri_to_url;
use serde::{Deserialize, Deserializer, Serialize, de};
use serde_json::Value;
use url::Url;

/// Parse `"128 MiB"`, `"1 GiB"`, `"500 KiB"`, or a bare byte count. Accepts
/// SI (KB/MB/GB) and binary (KiB/MiB/GiB/TiB) suffixes; treats the bare unit
/// `"B"` and unsuffixed numbers as raw bytes. Tolerant of whitespace and
/// case. The result MUST fit in `usize` (Lance's cache APIs take `usize`).
fn parse_byte_size(raw: &str) -> Result<usize, String> {
    let trimmed = raw.trim();
    if trimmed.is_empty() {
        return Err("byte-size value is empty".to_owned());
    }
    let split = trimmed
        .find(|c: char| c.is_ascii_alphabetic())
        .unwrap_or(trimmed.len());
    let (number, unit) = trimmed.split_at(split);
    let number: f64 = number
        .trim()
        .parse()
        .map_err(|_| format!("byte-size value {raw:?} is not a number"))?;
    if !number.is_finite() || number < 0.0 {
        return Err(format!("byte-size value {raw:?} must be non-negative"));
    }
    let multiplier: f64 = match unit.trim().to_ascii_lowercase().as_str() {
        "" | "b" => 1.0,
        "k" | "kb" => 1_000.0,
        "kib" => 1_024.0,
        "m" | "mb" => 1_000_000.0,
        "mib" => 1_048_576.0,
        "g" | "gb" => 1_000_000_000.0,
        "gib" => 1_073_741_824.0,
        "tib" => 1_099_511_627_776.0,
        other => {
            return Err(format!(
                "byte-size unit {other:?} not recognized (try MiB / GiB)"
            ));
        }
    };
    let bytes = number * multiplier;
    if !bytes.is_finite() || bytes > usize::MAX as f64 {
        return Err(format!("byte-size value {raw:?} overflows usize"));
    }
    Ok(bytes as usize)
}

fn deserialize_byte_size_opt<'de, D>(deserializer: D) -> Result<Option<usize>, D::Error>
where
    D: Deserializer<'de>,
{
    #[derive(Deserialize)]
    #[serde(untagged)]
    enum Repr {
        Bytes(u64),
        Text(String),
    }
    let repr: Option<Repr> = Option::deserialize(deserializer)?;
    match repr {
        None => Ok(None),
        Some(Repr::Bytes(value)) => usize::try_from(value).map(Some).map_err(de::Error::custom),
        Some(Repr::Text(value)) => parse_byte_size(&value).map(Some).map_err(de::Error::custom),
    }
}

/// Parse a CLI / env `--data-dir` argument into a `Url`. Delegates to Lance's
/// own `uri_to_url`, which handles every form pond cares about:
/// - bare paths like `/srv/pond` -> `file:///srv/pond`
/// - explicit `file://...` URIs
/// - object-store URIs (`s3://`, `gs://`, `az://`, ...)
/// - tilde expansion (`~/...`)
/// - Windows drive letters (we don't ship Windows, but the parser handles it)
///
/// Using Lance's parser keeps pond's CLI parse path identical to what Lance
/// uses internally - no risk of pond accepting a string Lance later rejects.
pub fn parse_data_dir(input: &str) -> Result<Url> {
    uri_to_url(input).with_context(|| format!("invalid --data-dir {input:?}"))
}

/// True when the URL is on the local filesystem. Mirrors Lance's
/// `ObjectStore::is_local` (lance-io/src/object_store.rs:541): the `file` and
/// `file+uring` schemes are local; everything else (incl. `memory://`) is not.
pub fn is_local(url: &Url) -> bool {
    matches!(url.scheme(), "file" | "file+uring")
}

/// Extract the filesystem `PathBuf` for local URLs. `None` for remote.
pub fn local_path(url: &Url) -> Option<PathBuf> {
    if is_local(url) {
        url.to_file_path().ok()
    } else {
        None
    }
}

/// URI string for a child of this location (typically one Lance dataset under
/// the data dir). Trims a single trailing slash on the base, then concatenates
/// with a `/` separator. This keeps `Dataset::open` / `Dataset::write` happy
/// on both filesystem and object-store backends - they want the URI form, not
/// a `url::Url`.
pub fn child_uri(base: &Url, suffix: &str) -> String {
    // For local URLs we strip the `file://` prefix so log lines and error
    // messages render as plain paths (`/srv/pond/sessions.lance`), matching
    // what pond used to emit before the URL migration.
    if let Some(path) = local_path(base) {
        return path.join(suffix).display().to_string();
    }
    format!("{}/{suffix}", base.as_str().trim_end_matches('/'))
}

/// Render a `Url` for human-readable log/diagnostic output: local URLs come
/// back as plain paths (no `file://` prefix); remote URLs stay verbatim.
pub fn display(url: &Url) -> String {
    if let Some(path) = local_path(url) {
        path.display().to_string()
    } else {
        url.to_string()
    }
}

/// Build a `Url` from a filesystem path. Convenience for tests and for
/// `resolve_data_dir` callers that hold a `PathBuf` already. The path must be
/// absolute (`url::Url::from_file_path` is a hard requirement on Unix); a
/// relative path gets canonicalized via `std::path::absolute` first.
pub fn url_for_path(path: impl AsRef<Path>) -> Result<Url> {
    let path = path.as_ref();
    let absolute = if path.is_absolute() {
        path.to_path_buf()
    } else {
        std::path::absolute(path)
            .with_context(|| format!("failed to absolutize {}", path.display()))?
    };
    Url::from_file_path(&absolute).map_err(|()| {
        anyhow!(
            "failed to convert path {} into a file:// URL",
            absolute.display()
        )
    })
}

/// Default `config.toml` body emitted by `pond config --print-schema`. Every
/// line is commented: pond ships built-in defaults, so the file is purely a
/// discoverable template and pond still works with no `config.toml` on disk.
pub const DEFAULT_CONFIG_TOML: &str = "\
# pond configuration.
#
# pond ships built-in defaults, so every setting here is optional - delete this
# file and pond still works. Uncomment and edit to override.

# Where pond looks for source data to import. One entry per adapter type
# (`claude-code`, `codex-cli`, ...). `pond sync` with no arguments syncs every
# entry; `pond sync <adapter>` syncs just one. With an empty `[sources]`,
# `pond sync` runs an interactive discovery against the known default paths
# and writes the picks back here.
#
# Future wrap: pond is single-namespace in v1 (spec.md#wire-namespace-resolution); `[sources]` is
# flat here. When multi-namespace pond lands, source registration becomes
# per-tenant under `[namespaces.<ns>.sources.<adapter>]`. Pre-v1 the schema
# is breakable; the rename is operationally free until a real second tenant
# exists.
#
# [sources.claude-code]
# enabled = true
# path = \"~/.claude/projects\"
#
# [sources.codex-cli]
# enabled = true
# path = \"~/.codex/sessions\"
#
# Set `enabled = false` to keep the section but skip it on `pond sync`;
# re-enable via `pond sync <adapter>`.

# Embeddings. Search runs hybrid (vector + FTS) whenever the store has any
# vectors, and FTS-only otherwise - the model loads lazily on the first hybrid
# query, so there's no cost on FTS-only corpora. `model` selects the
# HuggingFace XLM-RoBERTa model; `dim` declares its output width and is baked
# into the messages.vector schema on table creation - it must equal the
# model's hidden_size and be a multiple of 8 (IVF_PQ subspace stride).
#
# Common pairings:
#   model = \"intfloat/multilingual-e5-small\"   dim = 384   (default)
#   model = \"intfloat/multilingual-e5-base\"    dim = 768
#   model = \"intfloat/multilingual-e5-large\"   dim = 1024
#
# A different-dim model needs a fresh data dir; pond enforces this at the
# schema boundary.
#
# [embeddings]
# model = \"intfloat/multilingual-e5-small\"
# dim = 384

# Search tuning. Leave unset for Lance defaults; set when tuning IVF_PQ recall
# against a corpus.
#
# [search]
# nprobes = 16
# refine_factor = 2

# Storage maintenance. Tunes the compaction + cleanup pass that runs inside
# `pond sync` and `pond index optimize`.
#
# - `compaction_fragment_cap` is the sub-target fragment count past which the
#   compaction phase runs (it also runs once those fragments hold a whole target
#   fragment's worth of rows). Default 64 stops the automated sync re-compacting
#   the trailing fragment every pass; 0 compacts every pass.
# - `cleanup_older_than` is the manifest-retention window for the safe cleanup
#   pass. Accepts `Ns` / `Nm` / `Nh` / `Nd` (default `1d`). Versions older than
#   this are reclaimed by Lance's OCC-coordinated GC.
# - `index_lag_threshold` is the minimum unindexed-fragment count before a
#   per-intent append/rebuild runs in `pond index optimize`; the brute-force
#   fallback keeps queries correct while fragments accumulate. Default 4.
#
# [maintenance]
# compaction_fragment_cap = 64
# cleanup_older_than = \"1d\"
# index_lag_threshold = 4

# Long-running process caps. Both accept either a plain byte count or a
# humansize-style suffix (\"128 MiB\", \"1 GiB\"). Both are optional - leave
# unset to let pond pick the backend-aware default:
#   local FS  : index_cache = 256 MiB, metadata_cache = 128 MiB
#   remote    : index_cache = 2 GiB,   metadata_cache = 512 MiB
# Lance's library defaults (6 GiB / 1 GiB) are too generous for a per-session
# `pond mcp` process; tightening them is what keeps RSS under the 500 MiB target
# without measurable latency regressions on typical agent-history corpora.
#
# [runtime]
# index_cache_bytes    = \"256 MiB\"
# metadata_cache_bytes = \"128 MiB\"

# Object-store credentials and tuning, passed verbatim to Lance's
# `DatasetBuilder::with_storage_options`. Required only when `--data-dir` is
# an `s3://` / `gs://` / `az://` URI that needs auth or a non-default region.
# Keys follow the `object_store` crate's standard names. Environment
# variables of the same name are read by `object_store` automatically;
# values in this block override them. pond does not parse these.
#
# Future wrap: pond is single-namespace in v1 (spec.md#wire-namespace-resolution); `[storage]` is
# flat here on the assumption of one bucket per pond. When multi-namespace
# pond lands and tenants need separate buckets/regions, this becomes
# `[namespaces.<ns>.storage]`. Pre-v1 the schema is breakable; the rename is
# operationally free until a real second tenant exists.
#
# [storage]
# AWS_ACCESS_KEY_ID = \"...\"
# AWS_SECRET_ACCESS_KEY = \"...\"
# AWS_REGION = \"us-east-1\"
# AWS_ENDPOINT = \"https://minio.example.com\"  # for self-hosted MinIO
# allow_http = \"true\"                          # only for non-TLS endpoints
";

/// Top-level `config.toml` shape.
#[derive(Debug, Clone, PartialEq, Default, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct Config {
    #[serde(default)]
    pub embeddings: EmbeddingsConfig,
    #[serde(default)]
    pub search: SearchConfig,
    #[serde(default)]
    pub maintenance: MaintenanceConfig,
    #[serde(default)]
    pub runtime: RuntimeConfig,
    /// `[sources.<adapter>]` map: per-adapter config blobs the matching
    /// factory deserializes inside its `open()`. The shape is adapter-defined
    /// (filesystem adapters expect `{ path = "..." }`; API-backed adapters
    /// expect endpoint + auth keys), so this layer stays opaque. Empty by
    /// default; `pond sync` runs discovery into this map on first use.
    #[serde(default)]
    pub sources: BTreeMap<String, Value>,
    /// `[storage]` key=value pairs handed verbatim to Lance's
    /// `DatasetBuilder::with_storage_options` and `WriteParams.store_params`.
    /// Keys are the standard `object_store` config names
    /// (`AWS_ACCESS_KEY_ID`, `AWS_REGION`, `AWS_ENDPOINT`, etc.); see Lance's
    /// `DatasetBuilder::with_storage_options` doc for the per-scheme variants
    /// (S3 / GCS / Azure). pond does not parse or validate these; Lance does.
    /// Empty by default; required only when `--data-dir` is an object-store
    /// URI that needs credentials or a non-default region/endpoint. Values
    /// here override any matching environment variables.
    #[serde(default)]
    pub storage: BTreeMap<String, String>,
}

/// `[runtime]`: long-running process caps. Both knobs accept either a plain
/// byte count or a `humansize`-style suffix (`"128 MiB"`, `"1 GiB"`). Both are
/// optional - `None` lets `pond::substrate` pick the backend-aware default
/// (local FS gets a tight cap; object stores stay near Lance's defaults).
#[derive(Debug, Clone, PartialEq, Default, Serialize, Deserialize)]
#[serde(deny_unknown_fields, default)]
pub struct RuntimeConfig {
    #[serde(default, deserialize_with = "deserialize_byte_size_opt")]
    pub index_cache_bytes: Option<usize>,
    #[serde(default, deserialize_with = "deserialize_byte_size_opt")]
    pub metadata_cache_bytes: Option<usize>,
}

/// `[search]`: optional Lance vector-query tuning knobs.
#[derive(Debug, Clone, PartialEq, Default, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct SearchConfig {
    #[serde(default)]
    pub nprobes: Option<usize>,
    #[serde(default)]
    pub refine_factor: Option<u32>,
}

/// `[maintenance]`: storage-maintenance knobs shared by `pond sync` and
/// `pond index optimize`. All optional - omit and pond falls back to the
/// in-process defaults in `pond::substrate` (`DEFAULT_COMPACTION_FRAGMENT_CAP`,
/// `default_cleanup_older_than`, and the `index_lag_threshold` initializer).
#[derive(Debug, Clone, PartialEq, Default, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct MaintenanceConfig {
    /// Sub-target fragment count past which the compaction phase runs (it also
    /// runs once those fragments hold a whole target fragment's worth of rows).
    /// Default 64 stops the automated sync re-compacting the trailing fragment
    /// every pass; 0 compacts every pass.
    #[serde(default)]
    pub compaction_fragment_cap: Option<usize>,
    /// Manifest-retention window for the safe cleanup pass. Accepts
    /// `Ns`/`Nm`/`Nh`/`Nd` (default `1d`). Versions older than this are
    /// reclaimed by Lance's OCC-coordinated GC (`delete_unverified=false`),
    /// which never races a concurrent writer on any backend.
    #[serde(default)]
    pub cleanup_older_than: Option<String>,
    /// Minimum unindexed-fragment count below which `optimize_table_indices`
    /// skips the per-intent append/rebuild path; the brute-force fallback
    /// keeps queries correct while fragments accumulate. Default 4 trades a
    /// little query latency on cold fragments for far fewer remote index
    /// commits during high-rate ingest.
    #[serde(default)]
    pub index_lag_threshold: Option<usize>,
}

/// `[embeddings]`: model selector and vector dimension. There is no master
/// switch - the search path always runs hybrid when vectors exist in the
/// store and FTS-only when they don't (`has_embeddings()` is the only gate);
/// the candle/Metal model is `LazyEmbedder`-loaded on the first query that
/// actually needs it. `model` and `dim` are installed into the process at
/// startup via `embed::init_model_id` / `sessions::init_embedding_dim`, so
/// swapping models for a one-off experiment is a temporary config file - no
/// CLI flag and no per-call-site plumbing.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(deny_unknown_fields, default)]
pub struct EmbeddingsConfig {
    /// The embedding model id (spec.md#search): any XLM-RoBERTa model loadable
    /// by `candle-transformers`. Defaults to `intfloat/multilingual-e5-base`.
    pub model: String,
    /// Output dimension of `model`. Must equal the model's `hidden_size` and
    /// be divisible by 8 (the IVF_PQ subspace stride; see `embed::index_params`).
    /// Defaults to 768 (e5-base). Set to 384 for e5-small, 1024 for e5-large.
    pub dim: usize,
}

impl Default for EmbeddingsConfig {
    fn default() -> Self {
        Self {
            model: crate::embed::DEFAULT_MODEL_ID.to_owned(),
            dim: crate::sessions::DEFAULT_EMBEDDING_DIM,
        }
    }
}

/// Resolve pond's data directory. An explicit `--data-dir` / `POND_DATA_DIR`
/// wins (and may carry an `s3://` / `gs://` / `az://` URI); otherwise the
/// XDG-local fallback (`$XDG_DATA_HOME/pond`, then `$HOME/.local/share/pond`,
/// then `.pond`). `xdg_data_home` is honored only if absolute, per the XDG
/// base-directory spec.
pub fn resolve_data_dir(
    explicit: Option<Url>,
    xdg_data_home: Option<PathBuf>,
    home: Option<PathBuf>,
) -> Result<Url> {
    if let Some(location) = explicit {
        return Ok(location);
    }
    if let Some(xdg) = xdg_data_home.filter(|path| path.is_absolute()) {
        return url_for_path(xdg.join("pond"));
    }
    if let Some(home) = home {
        return url_for_path(home.join(".local").join("share").join("pond"));
    }
    // No HOME and no usable XDG var - stay usable rather than panic.
    url_for_path(PathBuf::from(".pond"))
}

/// Local default path for `config.toml`. URI-backed data dirs always land
/// here because the config file has to be local (it names the bucket and
/// any creds). XDG hierarchy: `$XDG_CONFIG_HOME/pond/config.toml`, then
/// `$HOME/.config/pond/config.toml`, then `.pond.toml` in cwd.
pub fn default_config_path(xdg_config_home: Option<PathBuf>, home: Option<PathBuf>) -> PathBuf {
    if let Some(xdg) = xdg_config_home.filter(|path| path.is_absolute()) {
        return xdg.join("pond").join("config.toml");
    }
    if let Some(home) = home {
        return home.join(".config").join("pond").join("config.toml");
    }
    PathBuf::from(".pond.toml")
}

impl Config {
    /// Load `config.toml` from `path` if it exists and validate it. A missing
    /// file yields the built-in defaults. On success the resolved embedding
    /// model id + dim are installed into the process (`OnceLock`-backed; only
    /// the first call per process sticks), so all downstream code paths see a
    /// consistent pair without per-handler plumbing.
    pub fn load(path: impl AsRef<Path>) -> Result<Self> {
        let path = path.as_ref();
        let config = if path.exists() {
            let text = std::fs::read_to_string(path)
                .with_context(|| format!("failed to read config {}", path.display()))?;
            toml::from_str::<Self>(&text)
                .with_context(|| format!("failed to parse config {}", path.display()))?
        } else {
            Self::default()
        };
        config.embeddings.validate()?;
        config.embeddings.install_runtime();
        if let Some(threshold) = config.maintenance.index_lag_threshold {
            crate::substrate::init_index_lag_threshold(threshold);
        }
        // Tilde expansion is per-adapter (inside each factory's `open()`):
        // an API-backed adapter has no path to expand, and only the
        // filesystem-shaped adapters need the helper. See `expand_home_under`.
        Ok(config)
    }

    /// Resolve the `[sources.<adapter>]` entries to drive `pond sync`. Only
    /// sections with `enabled = true` flow through; sections with
    /// `enabled = false` (or absent) are treated as opt-out and the
    /// per-adapter blob (minus `enabled`) is handed to the factory's
    /// `open()`. With `adapter = None` returns every enabled entry; with
    /// `Some(name)` returns just that one - and errors if it's not in
    /// config OR if it's currently disabled (the caller should then
    /// re-prompt or report).
    pub fn resolve_sources(&self, adapter: Option<&str>) -> Result<Vec<(String, Value)>> {
        match adapter {
            None => Ok(self
                .sources
                .iter()
                .filter_map(|(name, blob)| take_enabled(name, blob))
                .collect()),
            Some(name) => {
                let blob = self
                    .sources
                    .get(name)
                    .ok_or_else(|| anyhow!("no [sources.{name}] entry in config"))?;
                take_enabled(name, blob).map(|entry| vec![entry]).ok_or_else(|| {
                    anyhow!(
                        "source [{name}] is disabled (enabled = false); run `pond sync {name}` to re-enable"
                    )
                })
            }
        }
    }

    /// Names that are configured but currently `enabled = false`. Used by
    /// `pond sync` post-import to know not to re-probe an adapter the user
    /// already declined (the decline persists; re-prompt only via the
    /// positional override `pond sync <name>`).
    pub fn disabled_source_names(&self) -> Vec<&str> {
        self.sources
            .iter()
            .filter_map(|(name, blob)| {
                let enabled = blob
                    .get("enabled")
                    .and_then(Value::as_bool)
                    .unwrap_or(false);
                if enabled { None } else { Some(name.as_str()) }
            })
            .collect()
    }
}

/// Inner helper: return `Some((name, blob))` when the source section is
/// enabled, stripping the discriminator from the blob before handing it on;
/// `None` when the section is missing `enabled` or has `enabled = false`.
fn take_enabled(name: &str, blob: &Value) -> Option<(String, Value)> {
    let enabled = blob
        .get("enabled")
        .and_then(Value::as_bool)
        .unwrap_or(false);
    if !enabled {
        return None;
    }
    let mut clean = blob.clone();
    if let Some(obj) = clean.as_object_mut() {
        obj.remove("enabled");
    }
    Some((name.to_owned(), clean))
}

/// Tilde-expand `path` against an explicit `home`. Filesystem-shaped adapters
/// call this from inside their factory's `open()`. Tests use it directly to
/// exercise the rule without mutating the process-wide `HOME` env var
/// (`std::env::set_var` is `unsafe` under edition 2024 and pond forbids
/// unsafe code).
pub fn expand_home_under(path: &Path, home: &Path) -> PathBuf {
    let Some(text) = path.to_str() else {
        return path.to_path_buf();
    };
    if text == "~" {
        return home.to_path_buf();
    }
    if let Some(rest) = text.strip_prefix("~/") {
        return home.join(rest);
    }
    path.to_path_buf()
}

impl EmbeddingsConfig {
    /// Surface-level validation: model id non-empty and dim divisible by 8.
    /// The dim/model mismatch is the load-time check inside `CandleEmbedder::load`,
    /// which knows the model's `hidden_size`; what we can catch up front is the
    /// IVF_PQ subspace stride (`dim / 8` in `embed::index_params`).
    pub fn validate(&self) -> Result<()> {
        if self.model.trim().is_empty() {
            bail!("embeddings.model must be a non-empty HuggingFace model id");
        }
        if self.dim == 0 || !self.dim.is_multiple_of(8) {
            bail!(
                "embeddings.dim = {} must be a positive multiple of 8 (IVF_PQ subspace stride)",
                self.dim,
            );
        }
        Ok(())
    }

    /// Install model id + dim into the process. Idempotent: only the first
    /// call sticks (matches `OnceLock` semantics in `embed::init_model_id` and
    /// `sessions::init_embedding_dim`).
    pub fn install_runtime(&self) {
        crate::embed::init_model_id(self.model.clone());
        crate::sessions::init_embedding_dim(self.dim);
    }
}

#[cfg(test)]
mod tests {
    #![allow(clippy::expect_used, clippy::unwrap_used)]

    use super::*;
    use serde_json::Value;
    use tempfile::TempDir;

    #[test]
    fn validate_catches_empty_model_and_bad_dim() {
        assert!(EmbeddingsConfig::default().validate().is_ok());
        // Empty / whitespace-only model id is rejected: HuggingFace fetch
        // would fail far away from the config error.
        let bad_model = EmbeddingsConfig {
            model: "   ".to_owned(),
            dim: 768,
        };
        assert!(bad_model.validate().is_err());
        // Dim must divide 8 (PQ subspace stride in `embed::index_params`).
        let bad_dim = EmbeddingsConfig {
            model: "intfloat/multilingual-e5-base".to_owned(),
            dim: 100,
        };
        assert!(bad_dim.validate().is_err());
        // Zero is rejected too (would divide-by-zero inside index_params).
        let zero_dim = EmbeddingsConfig {
            model: "intfloat/multilingual-e5-base".to_owned(),
            dim: 0,
        };
        assert!(zero_dim.validate().is_err());
    }

    #[test]
    fn config_load_missing_file_falls_back_to_builtin() {
        let config = Config::load("/nonexistent/pond-config-xyz.toml").unwrap();
        assert_eq!(config.embeddings, EmbeddingsConfig::default());
    }

    #[test]
    fn default_config_toml_loads_to_the_builtin_defaults() {
        let dir = TempDir::new().unwrap();
        let path = dir.path().join("config.toml");
        std::fs::write(&path, DEFAULT_CONFIG_TOML).unwrap();
        // The shipped template is all comments, so it must load and validate as
        // the built-in defaults - a malformed template fails right here.
        let config = Config::load(&path).unwrap();
        assert_eq!(config.embeddings, EmbeddingsConfig::default());
        assert_eq!(config.embeddings.model, crate::embed::DEFAULT_MODEL_ID);
        assert_eq!(
            config.embeddings.dim,
            crate::sessions::DEFAULT_EMBEDDING_DIM
        );
    }

    #[test]
    fn resolve_data_dir_follows_explicit_then_xdg_then_home() {
        // An explicit `--data-dir` / `POND_DATA_DIR` wins over everything. The
        // explicit value can carry any URI form Lance accepts; here we test the
        // local-path form (parsing is delegated to Lance's `uri_to_url`).
        let explicit = parse_data_dir("/explicit").unwrap();
        let resolved = resolve_data_dir(
            Some(explicit.clone()),
            Some(PathBuf::from("/xdg")),
            Some(PathBuf::from("/home")),
        )
        .unwrap();
        assert_eq!(resolved, explicit);

        // An absolute XDG_DATA_HOME is used next.
        let resolved = resolve_data_dir(
            None,
            Some(PathBuf::from("/xdg")),
            Some(PathBuf::from("/home")),
        )
        .unwrap();
        assert!(is_local(&resolved));
        assert_eq!(local_path(&resolved).unwrap(), PathBuf::from("/xdg/pond"));

        // A relative XDG_DATA_HOME is ignored per the XDG spec; HOME is the fallback.
        let resolved = resolve_data_dir(
            None,
            Some(PathBuf::from("relative")),
            Some(PathBuf::from("/home")),
        )
        .unwrap();
        assert_eq!(
            local_path(&resolved).unwrap(),
            PathBuf::from("/home/.local/share/pond"),
        );

        // No XDG and no HOME - stays usable: returns the cwd-anchored `.pond`.
        // The result is absolute (Lance's URL conversion requires it), so we
        // just check that the URL ends with the relative path's components.
        let resolved = resolve_data_dir(None, None, None).unwrap();
        assert!(is_local(&resolved));
        assert!(
            local_path(&resolved).unwrap().ends_with(".pond"),
            "fallback path should end with .pond: {resolved}",
        );
    }

    #[test]
    fn expand_home_under_handles_tilde_forms() {
        let home = Path::new("/srv/me");
        assert_eq!(
            expand_home_under(Path::new("~"), home),
            PathBuf::from("/srv/me")
        );
        assert_eq!(
            expand_home_under(Path::new("~/.codex/sessions"), home),
            PathBuf::from("/srv/me/.codex/sessions"),
        );
        // Absolute paths pass through unchanged.
        assert_eq!(
            expand_home_under(Path::new("/etc/passwd"), home),
            PathBuf::from("/etc/passwd"),
        );
        // A leading `~something` (no slash) is not the home form - leave it.
        assert_eq!(
            expand_home_under(Path::new("~user/elsewhere"), home),
            PathBuf::from("~user/elsewhere"),
        );
    }

    #[test]
    fn resolve_sources_returns_one_or_all_or_errors() {
        let temp = TempDir::new().unwrap();
        let body = "\
[sources.claude-code]
enabled = true
path = \"/srv/claude\"

[sources.codex-cli]
enabled = true
path = \"/srv/codex\"

[sources.opencode]
enabled = false
";
        let path = temp.path().join("config.toml");
        std::fs::write(&path, body).expect("write config");
        let config = Config::load(&path).unwrap();

        // None -> only enabled entries
        let all = config.resolve_sources(None).unwrap();
        assert_eq!(all.len(), 2);
        let names: Vec<_> = all.iter().map(|(n, _)| n.as_str()).collect();
        assert!(names.contains(&"claude-code"));
        assert!(names.contains(&"codex-cli"));
        // The `enabled` discriminator never reaches the adapter blob.
        for (_, blob) in &all {
            assert!(blob.get("enabled").is_none(), "enabled should be stripped");
        }

        // Some(name) -> one entry, opaque JSON blob
        let one = config.resolve_sources(Some("codex-cli")).unwrap();
        assert_eq!(one.len(), 1);
        assert_eq!(one[0].0, "codex-cli");
        assert_eq!(
            one[0].1.get("path").and_then(Value::as_str),
            Some("/srv/codex"),
        );

        // Disabled positional -> errors with the recovery hint baked in.
        let disabled = config.resolve_sources(Some("opencode"));
        let err = disabled
            .expect_err("disabled adapter must error")
            .to_string();
        assert!(err.contains("enabled = false"), "got: {err}");
        assert!(err.contains("pond sync opencode"), "got: {err}");

        // Unknown -> error
        assert!(config.resolve_sources(Some("nope")).is_err());

        // disabled_source_names lists exactly the off ones.
        assert_eq!(config.disabled_source_names(), vec!["opencode"]);
    }

    #[test]
    fn memory_uri_is_classified_as_remote() {
        let url = parse_data_dir("memory:///pond-remote-test").expect("memory uri parses");
        assert!(
            !is_local(&url),
            "memory:// is not a local-filesystem URL: {url}",
        );
        assert!(
            local_path(&url).is_none(),
            "local_path must return None for non-file schemes",
        );
    }
}