vfa_tui/models/

model_policy.rs

//! Model-policy data model: the resolved per-agent/per-harness model and
//! reasoning-effort assignments generated by `scripts/model-policy.mjs`
//! (`catalog/model-assignments.json`), plus the command builder for mutating
//! the policy through that script.
//!
//! The TUI never resolves policy precedence itself — the Node script is the
//! single source of truth. The TUI reads the generated assignments index for
//! display and shells out to the script (dry-run first) for every mutation,
//! mirroring the export flow.

use std::collections::HashMap;

use serde::{Deserialize, Serialize};

use crate::error::TuiError;
use crate::security::validate::validate_argument;

/// Which policy fields a harness's executable format can express.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct HarnessCapability {
    pub model: bool,
    pub reasoning_effort: bool,
}

/// One resolved agent x harness assignment. `None` means "auto" — the managed
/// field is absent and the harness runtime default applies.
///
/// `model_provider` is codex-only: the `catalog/model-registry.json`
/// namespace that classified `model` (e.g. "ollama", "openrouter"), or
/// `None` for the default provider (OpenAI first-party) or non-codex
/// harnesses. `reasoning_effort` is projected as codex.toml
/// `model_reasoning_effort` or, for claude-code, the subagent frontmatter
/// `effort:` key.
///
/// `model_fallback_from` / `model_warning` surface provider lifecycle
/// (`status: "retiring"|"retired"` in `catalog/model-registry.json`):
/// `model_fallback_from` is the originally-pinned model id when
/// `scripts/model-policy.mjs` substituted a "retired" model's documented
/// successor (chain-followed) in `model`, else `None`. `model_warning` is
/// the fully-composed, ready-to-display warning text for a "retiring" pin or
/// a "retired" substitution, else `None`. Both arrive pre-composed from the
/// Node policy engine — the TUI never derives lifecycle logic itself, it
/// only renders what the engine already decided.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct ModelAssignment {
    pub agent_id: String,
    pub harness: String,
    pub model: Option<String>,
    #[serde(default)]
    pub model_provider: Option<String>,
    #[serde(default)]
    pub model_fallback_from: Option<String>,
    #[serde(default)]
    pub model_warning: Option<String>,
    pub reasoning_effort: Option<String>,
    pub model_source: String,
    pub reasoning_source: String,
}

/// Top-level structure of catalog/model-assignments.json.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct ModelAssignments {
    pub manifest_version: u32,
    pub generated_by: String,
    pub policy_sha256: String,
    pub capabilities: HashMap<String, HarnessCapability>,
    pub assignments: Vec<ModelAssignment>,
}

impl ModelAssignments {
    /// All assignments for one agent, in stable harness order.
    pub fn for_agent(&self, agent_id: &str) -> Vec<&ModelAssignment> {
        self.assignments
            .iter()
            .filter(|a| a.agent_id == agent_id)
            .collect()
    }
}

/// Harnesses the policy engine can project model config into today.
/// Mirrors HARNESS_CAPABILITIES in scripts/model-policy.mjs — the script is
/// authoritative; this list only drives UI cycling order.
pub const CAPABLE_HARNESSES: &[&str] = &["codex", "claude-code", "cursor"];

/// Reasoning-effort UI cycle. "auto" clears the field (harness default).
/// Union vocabulary across harnesses (codex, claude-code); the verified
/// per-harness/per-model subset lives in catalog/model-registry.json and is
/// enforced by scripts/model-policy.mjs, not here.
pub const REASONING_EFFORTS: &[&str] = &[
    "auto", "none", "minimal", "low", "medium", "high", "xhigh", "max",
];

/// Targeting scope for a model-policy batch operation.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ModelScope {
    /// Every agent in the catalog.
    All,
    /// Every agent of one provider.
    Provider(String),
    /// Every agent of one install role.
    Role(String),
    /// A single agent.
    Agent(String),
}

impl ModelScope {
    /// Render the `--scope` argument value understood by model-policy.mjs.
    pub fn to_flag(&self) -> String {
        match self {
            ModelScope::All => "all".to_string(),
            ModelScope::Provider(id) => format!("provider={id}"),
            ModelScope::Role(id) => format!("role={id}"),
            ModelScope::Agent(id) => format!("agent={id}"),
        }
    }

    /// Human-readable label for the builder form.
    pub fn display(&self) -> String {
        match self {
            ModelScope::All => "All agents".to_string(),
            ModelScope::Provider(id) => format!("Provider: {id}"),
            ModelScope::Role(id) => format!("Role: {id}"),
            ModelScope::Agent(id) => format!("Agent: {id}"),
        }
    }
}

/// A model-policy mutation to be executed as a subprocess:
/// `node scripts/model-policy.mjs set <args>`.
#[derive(Debug, Clone)]
pub struct ModelPolicyCommand {
    pub scope: ModelScope,
    pub harness: String,
    /// Model name or "auto"; `None` leaves the model field of the rule untouched.
    pub model: Option<String>,
    /// Reasoning effort or "auto"; `None` leaves the field untouched.
    pub reasoning: Option<String>,
    pub dry_run: bool,
}

impl ModelPolicyCommand {
    /// Validate all user-provided arguments against shell metacharacters.
    /// Semantic validation (per-harness model patterns, capability checks)
    /// stays in scripts/model-policy.mjs — the single source of truth.
    pub fn validate(&self) -> Result<(), TuiError> {
        match &self.scope {
            ModelScope::All => {}
            ModelScope::Provider(id) | ModelScope::Role(id) | ModelScope::Agent(id) => {
                validate_argument(id)?;
            }
        }
        validate_argument(&self.harness)?;
        if let Some(model) = &self.model {
            validate_argument(model)?;
        }
        if let Some(reasoning) = &self.reasoning {
            validate_argument(reasoning)?;
        }
        if self.model.is_none() && self.reasoning.is_none() {
            return Err(TuiError::ValidationRejected {
                value: "<empty>".to_string(),
                rule: "set a model and/or a reasoning effort".to_string(),
            });
        }
        Ok(())
    }

    /// Build the argument array for subprocess invocation (after the script path).
    pub fn to_args(&self) -> Vec<String> {
        let mut args = vec![
            "set".to_string(),
            "--scope".to_string(),
            self.scope.to_flag(),
            "--harness".to_string(),
            self.harness.clone(),
        ];
        if let Some(model) = &self.model {
            args.push("--model".to_string());
            args.push(model.clone());
        }
        if let Some(reasoning) = &self.reasoning {
            args.push("--reasoning".to_string());
            args.push(reasoning.clone());
        }
        if self.dry_run {
            args.push("--dry-run".to_string());
        }
        args
    }

    /// Render the full command string for display/preview.
    pub fn display_command(&self) -> String {
        format!("node scripts/model-policy.mjs {}", self.to_args().join(" "))
    }
}

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

    fn cmd(scope: ModelScope) -> ModelPolicyCommand {
        ModelPolicyCommand {
            scope,
            harness: "codex".to_string(),
            model: Some("gpt-5.4".to_string()),
            reasoning: Some("high".to_string()),
            dry_run: true,
        }
    }

    #[test]
    fn to_args_all_scope() {
        let args = cmd(ModelScope::All).to_args();
        assert_eq!(
            args,
            vec![
                "set",
                "--scope",
                "all",
                "--harness",
                "codex",
                "--model",
                "gpt-5.4",
                "--reasoning",
                "high",
                "--dry-run",
            ]
        );
    }

    #[test]
    fn to_args_role_scope_without_dry_run() {
        let mut c = cmd(ModelScope::Role("cloud-security-engineer".to_string()));
        c.dry_run = false;
        c.reasoning = None;
        let args = c.to_args();
        assert!(args.contains(&"role=cloud-security-engineer".to_string()));
        assert!(!args.contains(&"--dry-run".to_string()));
        assert!(!args.contains(&"--reasoning".to_string()));
    }

    #[test]
    fn to_args_provider_and_agent_scopes() {
        assert!(cmd(ModelScope::Provider("gcp".to_string()))
            .to_args()
            .contains(&"provider=gcp".to_string()));
        assert!(cmd(ModelScope::Agent(
            "gcp-firebase-developer-agent".to_string()
        ))
        .to_args()
        .contains(&"agent=gcp-firebase-developer-agent".to_string()));
    }

    #[test]
    fn validate_accepts_safe_command() {
        assert!(cmd(ModelScope::All).validate().is_ok());
    }

    #[test]
    fn validate_rejects_metachar_in_model() {
        let mut c = cmd(ModelScope::All);
        c.model = Some("gpt-5.4; rm -rf /".to_string());
        assert!(c.validate().is_err());
    }

    #[test]
    fn validate_rejects_metachar_in_scope_id() {
        let c = cmd(ModelScope::Role("role$(cmd)".to_string()));
        assert!(c.validate().is_err());
    }

    #[test]
    fn validate_rejects_empty_field_set() {
        let mut c = cmd(ModelScope::All);
        c.model = None;
        c.reasoning = None;
        assert!(c.validate().is_err());
    }

    #[test]
    fn display_command_format() {
        let display = cmd(ModelScope::All).display_command();
        assert!(display.starts_with("node scripts/model-policy.mjs set"));
        assert!(display.contains("--scope all"));
    }

    #[test]
    fn assignments_for_agent_filters() {
        let doc = ModelAssignments {
            manifest_version: 1,
            generated_by: "test".to_string(),
            policy_sha256: "0".repeat(64),
            capabilities: HashMap::new(),
            assignments: vec![
                ModelAssignment {
                    agent_id: "a".to_string(),
                    harness: "codex".to_string(),
                    model: Some("gpt-5.4".to_string()),
                    model_provider: None,
                    model_fallback_from: None,
                    model_warning: None,
                    reasoning_effort: Some("high".to_string()),
                    model_source: "all".to_string(),
                    reasoning_source: "all".to_string(),
                },
                ModelAssignment {
                    agent_id: "b".to_string(),
                    harness: "codex".to_string(),
                    model: None,
                    model_provider: None,
                    model_fallback_from: None,
                    model_warning: None,
                    reasoning_effort: None,
                    model_source: "default".to_string(),
                    reasoning_source: "default".to_string(),
                },
            ],
        };
        let for_a = doc.for_agent("a");
        assert_eq!(for_a.len(), 1);
        assert_eq!(for_a[0].model.as_deref(), Some("gpt-5.4"));
        assert!(doc.for_agent("missing").is_empty());
    }

    #[test]
    fn parses_generated_assignments_shape() {
        let json = r#"{
            "manifest_version": 1,
            "generated_by": "scripts/model-policy.mjs",
            "policy_sha256": "abc",
            "capabilities": {
                "codex": { "model": true, "reasoning_effort": true }
            },
            "assignments": [
                {
                    "agent_id": "x",
                    "harness": "codex",
                    "model": null,
                    "model_provider": null,
                    "reasoning_effort": "high",
                    "model_source": "default",
                    "reasoning_source": "all"
                }
            ]
        }"#;
        let parsed: ModelAssignments = serde_json::from_str(json).expect("parse");
        assert_eq!(parsed.assignments.len(), 1);
        assert!(parsed.assignments[0].model.is_none());
        // model_fallback_from / model_warning are absent in this fixture
        // (pre-lifecycle assignments index shape); #[serde(default)] must
        // still parse it cleanly as None rather than failing.
        assert!(parsed.assignments[0].model_fallback_from.is_none());
        assert!(parsed.assignments[0].model_warning.is_none());
    }

    #[test]
    fn parses_assignment_with_lifecycle_warning() {
        let json = r#"{
            "manifest_version": 1,
            "generated_by": "scripts/model-policy.mjs",
            "policy_sha256": "abc",
            "capabilities": {
                "codex": { "model": true, "reasoning_effort": true }
            },
            "assignments": [
                {
                    "agent_id": "x",
                    "harness": "codex",
                    "model": "gpt-5.5",
                    "model_provider": null,
                    "model_fallback_from": "gpt-5-2025-08-07",
                    "model_warning": "model \"gpt-5-2025-08-07\" was retired by the provider — projecting documented successor \"gpt-5.5\"; migrate the policy rule",
                    "reasoning_effort": "high",
                    "model_source": "agent:x",
                    "reasoning_source": "agent:x"
                }
            ]
        }"#;
        let parsed: ModelAssignments = serde_json::from_str(json).expect("parse");
        let a = &parsed.assignments[0];
        assert_eq!(a.model.as_deref(), Some("gpt-5.5"));
        assert_eq!(a.model_fallback_from.as_deref(), Some("gpt-5-2025-08-07"));
        assert!(a.model_warning.as_deref().unwrap().contains("was retired"));
    }
}