cmn-substrate 0.3.0

use std::collections::HashMap;
use std::fmt::{Display, Formatter};
use std::str::FromStr;

use anyhow::{anyhow, Result};
use serde::{Deserialize, Serialize};

pub const TASTE_SCHEMA: &str = "https://cmn.dev/schemas/v1/taste.json";

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum GateAction {
    Block,
    Warn,
    Proceed,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum GateOperation {
    Spawn,
    Grow,
    Absorb,
    Bond,
    Replicate,
    Taste,
    Sense,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum TasteVerdict {
    Sweet,
    Fresh,
    Safe,
    Rotten,
    Toxic,
}

impl TasteVerdict {
    pub const ALL: [Self; 5] = [
        Self::Sweet,
        Self::Fresh,
        Self::Safe,
        Self::Rotten,
        Self::Toxic,
    ];

    pub fn as_str(self) -> &'static str {
        match self {
            Self::Sweet => "sweet",
            Self::Fresh => "fresh",
            Self::Safe => "safe",
            Self::Rotten => "rotten",
            Self::Toxic => "toxic",
        }
    }

    pub fn allows_use(self) -> bool {
        !matches!(self, Self::Toxic)
    }

    pub fn base_gate_action(verdict: Option<Self>) -> GateAction {
        match verdict {
            None | Some(Self::Toxic) => GateAction::Block,
            Some(Self::Rotten) => GateAction::Warn,
            Some(Self::Safe | Self::Fresh | Self::Sweet) => GateAction::Proceed,
        }
    }

    pub fn gate_action_for(operation: GateOperation, verdict: Option<Self>) -> GateAction {
        Self::gate_action_for_env(operation, verdict, false)
    }

    /// Gate action with optional sandbox override.
    /// In sandbox mode, untasted and rotten spores proceed (toxic still blocks).
    pub fn gate_action_for_env(
        operation: GateOperation,
        verdict: Option<Self>,
        sandboxed: bool,
    ) -> GateAction {
        match operation {
            GateOperation::Taste | GateOperation::Sense => GateAction::Proceed,
            GateOperation::Spawn
            | GateOperation::Grow
            | GateOperation::Absorb
            | GateOperation::Bond
            | GateOperation::Replicate => {
                if sandboxed && verdict != Some(Self::Toxic) {
                    GateAction::Proceed
                } else {
                    Self::base_gate_action(verdict)
                }
            }
        }
    }
}

impl Display for TasteVerdict {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        f.write_str(self.as_str())
    }
}

impl FromStr for TasteVerdict {
    type Err = anyhow::Error;

    fn from_str(value: &str) -> anyhow::Result<Self> {
        match value {
            "sweet" => Ok(Self::Sweet),
            "fresh" => Ok(Self::Fresh),
            "safe" => Ok(Self::Safe),
            "rotten" => Ok(Self::Rotten),
            "toxic" => Ok(Self::Toxic),
            _ => Err(anyhow!(
                "Invalid verdict '{}'. Must be one of: sweet, fresh, safe, rotten, toxic",
                value
            )),
        }
    }
}

impl Serialize for TasteVerdict {
    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        serializer.serialize_str(self.as_str())
    }
}

impl<'de> Deserialize<'de> for TasteVerdict {
    fn deserialize<D>(deserializer: D) -> std::result::Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        let value = String::deserialize(deserializer)?;
        Self::from_str(&value).map_err(serde::de::Error::custom)
    }
}

/// Full Taste manifest (content-addressed)
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct Taste {
    #[serde(rename = "$schema")]
    pub schema: String,
    pub capsule: TasteCapsule,
    pub capsule_signature: String,
}

/// Taste capsule containing uri, core, and core_signature
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct TasteCapsule {
    pub uri: String,
    pub core: TasteCore,
    pub core_signature: String,
}

/// Core taste data (part of hash)
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct TasteCore {
    pub domain: String,
    pub key: String,
    pub target_uri: String,
    pub verdict: TasteVerdict,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub notes: Vec<String>,
    pub tasted_at_epoch_ms: u64,
}

/// Aggregated verdict counts across multiple taste reports.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VerdictSummary {
    pub counts: HashMap<TasteVerdict, u64>,
    pub total: u64,
}

impl VerdictSummary {
    /// Aggregate verdict counts from a slice of `Taste` manifests.
    pub fn from_tastes(tastes: &[Taste]) -> Self {
        let mut counts = HashMap::with_capacity(TasteVerdict::ALL.len());
        for v in TasteVerdict::ALL {
            counts.insert(v, 0);
        }
        for taste in tastes {
            *counts.entry(taste.capsule.core.verdict).or_insert(0) += 1;
        }
        Self {
            counts,
            total: tastes.len() as u64,
        }
    }

    /// Produce a JSON-friendly map of verdict name → count (all verdicts present, defaulting to 0).
    pub fn to_json_map(&self) -> serde_json::Map<String, serde_json::Value> {
        let mut map = serde_json::Map::new();
        for v in TasteVerdict::ALL {
            let count = self.counts.get(&v).copied().unwrap_or(0);
            map.insert(
                v.as_str().to_string(),
                serde_json::Value::Number(count.into()),
            );
        }
        map
    }
}

/// Return the latest report for each `(taster domain, taster key, target_uri)`.
pub fn latest_taste_reports_by_taster(tastes: &[Taste]) -> Vec<&Taste> {
    let mut latest: HashMap<(&str, &str, &str), &Taste> = HashMap::new();
    for taste in tastes {
        let key = (
            taste.capsule.core.domain.as_str(),
            taste.capsule.core.key.as_str(),
            taste.capsule.core.target_uri.as_str(),
        );
        match latest.get(&key) {
            Some(existing)
                if existing.capsule.core.tasted_at_epoch_ms
                    >= taste.capsule.core.tasted_at_epoch_ms => {}
            _ => {
                latest.insert(key, taste);
            }
        }
    }
    latest.into_values().collect()
}

impl Taste {
    pub fn uri(&self) -> &str {
        &self.capsule.uri
    }

    pub fn target_uri(&self) -> &str {
        &self.capsule.core.target_uri
    }

    pub fn author_domain(&self) -> &str {
        &self.capsule.core.domain
    }

    pub fn timestamp_ms(&self) -> u64 {
        self.capsule.core.tasted_at_epoch_ms
    }

    pub fn embedded_core_key(&self) -> Option<&str> {
        let key = self.capsule.core.key.as_str();
        (!key.is_empty()).then_some(key)
    }

    pub fn verify_core_signature(&self, author_key: &str) -> Result<()> {
        crate::verify_json_signature(&self.capsule.core, &self.capsule.core_signature, author_key)
    }

    pub fn verify_capsule_signature(&self, host_key: &str) -> Result<()> {
        crate::verify_json_signature(&self.capsule, &self.capsule_signature, host_key)
    }

    pub fn verify_signatures(&self, host_key: &str, author_key: &str) -> Result<()> {
        self.verify_core_signature(author_key)?;
        self.verify_capsule_signature(host_key)
    }

    /// Verify both signatures using the same key (self-hosted case where host == author).
    pub fn verify_self_hosted_signatures(&self, key: &str) -> Result<()> {
        self.verify_signatures(key, key)
    }

    pub fn computed_uri_hash(&self) -> Result<String> {
        crate::crypto::hash::compute_signed_core_hash(
            &self.capsule.core,
            &self.capsule.core_signature,
        )
    }

    pub fn verify_uri_hash(&self, expected_hash: &str) -> Result<()> {
        let actual_hash = self.computed_uri_hash()?;
        super::verify_expected_uri_hash(&actual_hash, expected_hash)
    }
}

// ---------------------------------------------------------------------------
// Lightweight local verdict record
// ---------------------------------------------------------------------------

/// A lightweight local taste verdict record for client-side caching.
///
/// Unlike the full [`Taste`] manifest (which is cryptographically signed and
/// content-addressed), this struct is for clients to persist their own taste
/// results locally — e.g. after an LLM safety review or manual inspection.
///
/// ```
/// use substrate::TasteVerdictRecord;
/// use substrate::TasteVerdict;
///
/// let record = TasteVerdictRecord::new(TasteVerdict::Safe, Some("Reviewed, looks good"));
/// let json = serde_json::to_string_pretty(&record).unwrap();
/// let parsed: TasteVerdictRecord = serde_json::from_str(&json).unwrap();
/// assert_eq!(parsed.verdict, TasteVerdict::Safe);
/// ```
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct TasteVerdictRecord {
    pub verdict: TasteVerdict,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub notes: Option<String>,
    pub tasted_at_epoch_ms: u64,
}

impl TasteVerdictRecord {
    /// Create a new verdict record stamped with the current time.
    pub fn new(verdict: TasteVerdict, notes: Option<&str>) -> Self {
        let now_ms = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap_or_default()
            .as_millis() as u64;
        Self {
            verdict,
            notes: notes.map(|s| s.to_string()),
            tasted_at_epoch_ms: now_ms,
        }
    }

    /// Create a verdict record with an explicit timestamp.
    pub fn with_timestamp(verdict: TasteVerdict, notes: Option<&str>, epoch_ms: u64) -> Self {
        Self {
            verdict,
            notes: notes.map(|s| s.to_string()),
            tasted_at_epoch_ms: epoch_ms,
        }
    }

    /// Whether this verdict allows the spore to be used (i.e. not toxic).
    pub fn allows_use(&self) -> bool {
        self.verdict.allows_use()
    }

    /// Gate action for a given operation based on this verdict.
    pub fn gate_action_for(&self, operation: GateOperation) -> GateAction {
        TasteVerdict::gate_action_for(operation, Some(self.verdict))
    }
}

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

    use super::*;

    fn taste(domain: &str, key: &str, target: &str, verdict: TasteVerdict, ts: u64) -> Taste {
        Taste {
            schema: TASTE_SCHEMA.to_string(),
            capsule: TasteCapsule {
                uri: format!("cmn://{domain}/taste/b3.fake{ts}"),
                core: TasteCore {
                    domain: domain.to_string(),
                    key: key.to_string(),
                    target_uri: target.to_string(),
                    verdict,
                    notes: vec![],
                    tasted_at_epoch_ms: ts,
                },
                core_signature: "ed25519.fake".to_string(),
            },
            capsule_signature: "ed25519.fake".to_string(),
        }
    }

    #[test]
    fn test_latest_taste_reports_by_taster_uses_newest_per_target() {
        let reports = vec![
            taste(
                "alice.dev",
                "ed25519.a",
                "cmn://target.dev/b3.x",
                TasteVerdict::Safe,
                10,
            ),
            taste(
                "alice.dev",
                "ed25519.a",
                "cmn://target.dev/b3.x",
                TasteVerdict::Toxic,
                20,
            ),
            taste(
                "bob.dev",
                "ed25519.b",
                "cmn://target.dev/b3.x",
                TasteVerdict::Fresh,
                5,
            ),
        ];

        let latest = latest_taste_reports_by_taster(&reports);
        assert_eq!(latest.len(), 2);
        assert!(latest.iter().any(|t| {
            t.author_domain() == "alice.dev" && t.capsule.core.verdict == TasteVerdict::Toxic
        }));
        assert!(latest.iter().any(|t| {
            t.author_domain() == "bob.dev" && t.capsule.core.verdict == TasteVerdict::Fresh
        }));
    }

    #[test]
    fn test_base_gate_action() {
        assert_eq!(TasteVerdict::base_gate_action(None), GateAction::Block);
        assert_eq!(
            TasteVerdict::base_gate_action(Some(TasteVerdict::Toxic)),
            GateAction::Block
        );
        assert_eq!(
            TasteVerdict::base_gate_action(Some(TasteVerdict::Rotten)),
            GateAction::Warn
        );
        assert_eq!(
            TasteVerdict::base_gate_action(Some(TasteVerdict::Safe)),
            GateAction::Proceed
        );
    }

    #[test]
    fn test_gate_action_for_operation() {
        assert_eq!(
            TasteVerdict::gate_action_for(GateOperation::Spawn, Some(TasteVerdict::Rotten)),
            GateAction::Warn
        );
        assert_eq!(
            TasteVerdict::gate_action_for(GateOperation::Taste, Some(TasteVerdict::Toxic)),
            GateAction::Proceed
        );
        assert_eq!(
            TasteVerdict::gate_action_for(GateOperation::Sense, None),
            GateAction::Proceed
        );
    }

    #[test]
    fn test_gate_action_sandbox_skips_untasted() {
        assert_eq!(
            TasteVerdict::gate_action_for_env(GateOperation::Spawn, None, true),
            GateAction::Proceed
        );
    }

    #[test]
    fn test_gate_action_sandbox_skips_rotten() {
        assert_eq!(
            TasteVerdict::gate_action_for_env(
                GateOperation::Bond,
                Some(TasteVerdict::Rotten),
                true
            ),
            GateAction::Proceed
        );
    }

    #[test]
    fn test_gate_action_sandbox_still_blocks_toxic() {
        assert_eq!(
            TasteVerdict::gate_action_for_env(
                GateOperation::Spawn,
                Some(TasteVerdict::Toxic),
                true
            ),
            GateAction::Block
        );
    }
}