//! Orchestrator request model (ARCHITECTURE §14.3).
//!
//! An *orchestrator* agent does not spawn child processes itself: it **delegates**
//! agent lifecycle to IdeA (the single source of truth) by dropping a JSON request
//! file under `<project_root>/.ideai/requests/<requester-id>/*.json`. This module
//! owns the **pure** request model: the wire-level [`OrchestratorRequest`] (serde,
//! camelCase) and its validation into a well-formed [`OrchestratorCommand`].
//!
//! It is I/O-free: parsing the file, dispatching to use cases and writing the
//! response are infrastructure/application concerns. Keeping the model here means
//! validation invariants (known action, required fields present) are unit-testable
//! without touching the filesystem.

use serde::{Deserialize, Serialize};

use crate::ids::NodeId;
use crate::skill::SkillScope;

/// Errors raised while validating a raw [`OrchestratorRequest`].
#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
pub enum OrchestratorError {
    /// The requested action/type is not one of the supported actions.
    #[error("unknown orchestrator action: {0}")]
    UnknownAction(String),
    /// A field required by the chosen action is missing or empty.
    #[error("missing required field `{field}` for action `{action}`")]
    MissingField {
        /// The action being validated.
        action: String,
        /// The required field that was absent or empty.
        field: String,
    },
    /// The `scope` field is present but not a recognised skill scope.
    #[error("unknown skill scope `{scope}` for action `{action}`")]
    UnknownScope {
        /// The action being validated.
        action: String,
        /// The offending scope value.
        scope: String,
    },
    /// The `visibility` field is present but not recognised.
    #[error("unknown visibility `{visibility}` for action `{action}`")]
    UnknownVisibility {
        /// The action being validated.
        action: String,
        /// The offending visibility value.
        visibility: String,
    },
}

/// The raw, wire-level orchestrator request as deserialised from a request file.
///
/// All payload fields are optional at this layer; which ones are *required*
/// depends on `action` and is enforced by [`OrchestratorRequest::validate`]. This
/// keeps deserialisation total (any JSON object shape parses) and pushes the
/// metier invariants into one explicit, tested place.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct OrchestratorRequest {
    /// Legacy v1 action (`spawn_agent`, `stop_agent`, `update_agent_context`).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub action: Option<String>,
    /// V2 action type (`agent.run`, `agent.stop`, `agent.message`,
    /// `agent.update_context`, `skill.create`). `type` is reserved in Rust, so the
    /// field is renamed.
    #[serde(default, rename = "type", skip_serializing_if = "Option::is_none")]
    pub request_type: Option<String>,
    /// Optional requester id/name, informational at this layer.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub requested_by: Option<String>,
    /// Target agent display name (required by every v1 action).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub name: Option<String>,
    /// V2 target agent display name (`agent.run`/`agent.stop`).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub target_agent: Option<String>,
    /// Runtime profile slug/name (required by `spawn_agent`).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub profile: Option<String>,
    /// Context reference: for `spawn_agent` the relative `.md` path is informative
    /// (the manifest owns the real path); for `update_agent_context` **and**
    /// `create_skill` this carries the **new Markdown body** to write.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub context: Option<String>,
    /// Task/message carried by `agent.run` (fire-and-forget) and required by
    /// `agent.message` (synchronous ask: the prompt sent to the target agent).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub task: Option<String>,
    /// Whether a spawned agent should stay in the background or attach to a cell.
    ///
    /// Accepted values are `"background"` (default) and `"visible"`. A visible
    /// spawn must also provide [`Self::node_id`].
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub visibility: Option<String>,
    /// Target layout leaf for `visibility: "visible"`.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub node_id: Option<NodeId>,
    /// V2 visible-cell target (`attachToCell`), equivalent to `nodeId`.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub attach_to_cell: Option<NodeId>,
    /// Skill scope for `create_skill` (`"global"` or `"project"`, case-insensitive).
    /// Optional — absent/empty defaults to [`SkillScope::Project`]. Ignored by the
    /// other actions.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub scope: Option<String>,
}

/// A validated orchestrator command — the only thing the application layer acts on.
///
/// Each variant carries exactly the fields its action needs; constructing one is
/// proof the request was well-formed (Parse, don't validate).
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum OrchestratorCommand {
    /// Create the agent if unknown (with `profile` + optional initial context),
    /// then launch it — exactly as the UI would.
    SpawnAgent {
        /// Target agent display name.
        name: String,
        /// Profile slug/name to resolve against the configured profiles. Required
        /// for legacy `spawn_agent`; optional for `agent.run` when the agent
        /// already exists and its manifest owns the profile id.
        profile: Option<String>,
        /// Optional initial `.md` body for a freshly-created agent.
        context: Option<String>,
        /// Desired visibility for the launched session.
        visibility: OrchestratorVisibility,
    },
    /// Stop a running agent by killing its terminal session.
    StopAgent {
        /// Target agent display name.
        name: String,
    },
    /// Overwrite an agent's `.md` context with a new body.
    UpdateAgentContext {
        /// Target agent display name.
        name: String,
        /// New Markdown body.
        context: String,
    },
    /// Ask a target agent a question/task and **wait for its reply**.
    ///
    /// Unlike [`Self::SpawnAgent`] (fire-and-forget lifecycle), this is the
    /// synchronous inter-agent rendezvous (ARCHITECTURE §17.4): the application
    /// layer drives the target's structured [`crate::ports::AgentSession`], waits
    /// for the turn's `Final`, and returns its content to the requester. The
    /// target is launched in structured mode first if it is not already live.
    AskAgent {
        /// Target agent display name (resolved case-insensitively).
        target: String,
        /// The task/message to send and await a reply for.
        task: String,
    },
    /// List the project's agents (discovery) — exactly the data the UI reads from
    /// the manifest. Carries no argument: the dispatch resolves the agents against
    /// the project it is dispatched for.
    ListAgents,
    /// Create a reusable skill in the given scope — exactly as the UI would.
    CreateSkill {
        /// Display name (also the `.md` stem on disk).
        name: String,
        /// Markdown body of the skill.
        content: String,
        /// Scope the skill is created in (defaults to [`SkillScope::Project`]).
        scope: SkillScope,
    },
}

/// Where IdeA should place a launched agent session.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum OrchestratorVisibility {
    /// Launch or keep running without attaching to a layout cell.
    Background,
    /// Launch or re-attach visibly in one layout leaf.
    Visible {
        /// Target layout leaf.
        node_id: NodeId,
    },
}

impl OrchestratorRequest {
    /// Validates the raw request into a well-formed [`OrchestratorCommand`].
    ///
    /// Invariants enforced here (ARCHITECTURE §14.3):
    /// - `action` must be a known v1 action,
    /// - `name` is required (non-empty) for every action,
    /// - `spawn_agent` additionally requires a non-empty `profile`,
    /// - `update_agent_context` additionally requires a `context` body.
    ///
    /// # Errors
    /// [`OrchestratorError::UnknownAction`] for an unsupported action;
    /// [`OrchestratorError::MissingField`] when a required field is absent/empty.
    pub fn validate(&self) -> Result<OrchestratorCommand, OrchestratorError> {
        let action = self.action_name()?;
        match action {
            "spawn_agent" => Ok(OrchestratorCommand::SpawnAgent {
                name: self.require_name(action)?,
                profile: Some(self.require("profile", action, self.profile.as_deref())?),
                context: self.context.as_ref().filter(|c| !c.is_empty()).cloned(),
                visibility: self.parse_visibility(action)?,
            }),
            "agent.run" => Ok(OrchestratorCommand::SpawnAgent {
                name: self.require_target_agent(action)?,
                profile: self
                    .profile
                    .as_ref()
                    .filter(|p| !p.trim().is_empty())
                    .cloned(),
                context: self
                    .context
                    .as_ref()
                    .or(self.task.as_ref())
                    .filter(|c| !c.is_empty())
                    .cloned(),
                visibility: self.parse_visibility(action)?,
            }),
            "stop_agent" => Ok(OrchestratorCommand::StopAgent {
                name: self.require_name(action)?,
            }),
            "agent.stop" => Ok(OrchestratorCommand::StopAgent {
                name: self.require_target_agent(action)?,
            }),
            "update_agent_context" => Ok(OrchestratorCommand::UpdateAgentContext {
                name: self.require_name(action)?,
                context: self.require("context", action, self.context.as_deref())?,
            }),
            "agent.update_context" => Ok(OrchestratorCommand::UpdateAgentContext {
                name: self.require_target_agent(action)?,
                context: self.require("context", action, self.context.as_deref())?,
            }),
            "agent.message" => Ok(OrchestratorCommand::AskAgent {
                target: self.require_target_agent(action)?,
                task: self.require("task", action, self.task.as_deref())?,
            }),
            "list_agents" | "agent.list" => Ok(OrchestratorCommand::ListAgents),
            "create_skill" | "skill.create" => Ok(OrchestratorCommand::CreateSkill {
                name: self.require_name(action)?,
                content: self.require("context", action, self.context.as_deref())?,
                scope: self.parse_scope(action)?,
            }),
            other => Err(OrchestratorError::UnknownAction(other.to_owned())),
        }
    }

    /// Parses the optional `scope` field into a [`SkillScope`], defaulting to
    /// [`SkillScope::Project`] when absent or empty.
    ///
    /// # Errors
    /// [`OrchestratorError::UnknownScope`] when the value is neither `global` nor
    /// `project` (case-insensitive).
    fn parse_scope(&self, action: &str) -> Result<SkillScope, OrchestratorError> {
        match self.scope.as_deref().map(str::trim) {
            None | Some("") => Ok(SkillScope::Project),
            Some(s) if s.eq_ignore_ascii_case("project") => Ok(SkillScope::Project),
            Some(s) if s.eq_ignore_ascii_case("global") => Ok(SkillScope::Global),
            Some(other) => Err(OrchestratorError::UnknownScope {
                action: action.to_owned(),
                scope: other.to_owned(),
            }),
        }
    }

    /// Parses `visibility` for `spawn_agent`, defaulting to background.
    fn parse_visibility(&self, action: &str) -> Result<OrchestratorVisibility, OrchestratorError> {
        match self.visibility.as_deref().map(str::trim) {
            None | Some("") | Some("background") => Ok(OrchestratorVisibility::Background),
            Some("visible") => {
                let node_id = self.node_id.or(self.attach_to_cell).ok_or_else(|| {
                    OrchestratorError::MissingField {
                        action: action.to_owned(),
                        field: "nodeId".to_owned(),
                    }
                })?;
                Ok(OrchestratorVisibility::Visible { node_id })
            }
            Some(other) => Err(OrchestratorError::UnknownVisibility {
                action: action.to_owned(),
                visibility: other.to_owned(),
            }),
        }
    }

    /// Requires a non-empty `name`, shared by all actions.
    fn require_name(&self, action: &str) -> Result<String, OrchestratorError> {
        self.require("name", action, self.name.as_deref())
    }

    fn require_target_agent(&self, action: &str) -> Result<String, OrchestratorError> {
        self.require(
            "targetAgent",
            action,
            self.target_agent.as_deref().or(self.name.as_deref()),
        )
    }

    fn action_name(&self) -> Result<&str, OrchestratorError> {
        self.request_type
            .as_deref()
            .or(self.action.as_deref())
            .map(str::trim)
            .filter(|a| !a.is_empty())
            .ok_or_else(|| OrchestratorError::MissingField {
                action: "<request>".to_owned(),
                field: "type".to_owned(),
            })
    }

    /// Requires `value` to be present and non-empty (after trimming), else a
    /// [`OrchestratorError::MissingField`] naming `field`/`action`.
    fn require(
        &self,
        field: &str,
        action: &str,
        value: Option<&str>,
    ) -> Result<String, OrchestratorError> {
        match value {
            Some(v) if !v.trim().is_empty() => Ok(v.trim().to_owned()),
            _ => Err(OrchestratorError::MissingField {
                action: action.to_owned(),
                field: field.to_owned(),
            }),
        }
    }
}

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

    fn req(json: &str) -> OrchestratorRequest {
        serde_json::from_str(json).expect("valid json")
    }

    #[test]
    fn spawn_agent_parses_and_validates() {
        let r = req(
            r#"{ "action": "spawn_agent", "name": "dev-backend", "profile": "claude-code", "context": "agents/dev-backend.md" }"#,
        );
        assert_eq!(
            r.validate().unwrap(),
            OrchestratorCommand::SpawnAgent {
                name: "dev-backend".to_owned(),
                profile: Some("claude-code".to_owned()),
                context: Some("agents/dev-backend.md".to_owned()),
                visibility: OrchestratorVisibility::Background,
            }
        );
    }

    #[test]
    fn spawn_agent_without_context_is_valid() {
        let r = req(r#"{ "action": "spawn_agent", "name": "a", "profile": "claude-code" }"#);
        assert_eq!(
            r.validate().unwrap(),
            OrchestratorCommand::SpawnAgent {
                name: "a".to_owned(),
                profile: Some("claude-code".to_owned()),
                context: None,
                visibility: OrchestratorVisibility::Background,
            }
        );
    }

    #[test]
    fn spawn_agent_visible_requires_and_carries_node_id() {
        let node = uuid::Uuid::from_u128(42);
        let r = req(&format!(
            r#"{{ "action": "spawn_agent", "name": "a", "profile": "claude-code", "visibility": "visible", "nodeId": "{node}" }}"#
        ));
        assert_eq!(
            r.validate().unwrap(),
            OrchestratorCommand::SpawnAgent {
                name: "a".to_owned(),
                profile: Some("claude-code".to_owned()),
                context: None,
                visibility: OrchestratorVisibility::Visible {
                    node_id: NodeId::from_uuid(node)
                },
            }
        );

        let missing = req(
            r#"{ "action": "spawn_agent", "name": "a", "profile": "claude-code", "visibility": "visible" }"#,
        );
        assert_eq!(
            missing.validate(),
            Err(OrchestratorError::MissingField {
                action: "spawn_agent".to_owned(),
                field: "nodeId".to_owned(),
            })
        );
    }

    #[test]
    fn spawn_agent_missing_profile_is_rejected() {
        let r = req(r#"{ "action": "spawn_agent", "name": "a" }"#);
        assert_eq!(
            r.validate(),
            Err(OrchestratorError::MissingField {
                action: "spawn_agent".to_owned(),
                field: "profile".to_owned(),
            })
        );
    }

    #[test]
    fn agent_run_accepts_type_target_agent_and_optional_profile() {
        let r = req(
            r#"{ "type": "agent.run", "requestedBy": "Main", "targetAgent": "Architect", "task": "Analyse", "visibility": "background" }"#,
        );
        assert_eq!(
            r.validate().unwrap(),
            OrchestratorCommand::SpawnAgent {
                name: "Architect".to_owned(),
                profile: None,
                context: Some("Analyse".to_owned()),
                visibility: OrchestratorVisibility::Background,
            }
        );
    }

    #[test]
    fn agent_run_visible_accepts_attach_to_cell() {
        let node = uuid::Uuid::from_u128(77);
        let r = req(&format!(
            r#"{{ "type": "agent.run", "targetAgent": "Architect", "profile": "claude-code", "visibility": "visible", "attachToCell": "{node}" }}"#
        ));
        assert_eq!(
            r.validate().unwrap(),
            OrchestratorCommand::SpawnAgent {
                name: "Architect".to_owned(),
                profile: Some("claude-code".to_owned()),
                context: None,
                visibility: OrchestratorVisibility::Visible {
                    node_id: NodeId::from_uuid(node)
                },
            }
        );
    }

    #[test]
    fn agent_message_validates_target_and_task() {
        let r = req(
            r#"{ "type": "agent.message", "requestedBy": "Main", "targetAgent": "Architect", "task": "Analyse §17" }"#,
        );
        assert_eq!(
            r.validate().unwrap(),
            OrchestratorCommand::AskAgent {
                target: "Architect".to_owned(),
                task: "Analyse §17".to_owned(),
            }
        );
    }

    #[test]
    fn agent_message_missing_task_is_rejected() {
        let r = req(r#"{ "type": "agent.message", "targetAgent": "Architect" }"#);
        assert_eq!(
            r.validate(),
            Err(OrchestratorError::MissingField {
                action: "agent.message".to_owned(),
                field: "task".to_owned(),
            })
        );
    }

    #[test]
    fn agent_message_missing_target_is_rejected() {
        let r = req(r#"{ "type": "agent.message", "task": "do it" }"#);
        assert_eq!(
            r.validate(),
            Err(OrchestratorError::MissingField {
                action: "agent.message".to_owned(),
                field: "targetAgent".to_owned(),
            })
        );
    }

    #[test]
    fn stop_agent_validates() {
        let r = req(r#"{ "action": "stop_agent", "name": "dev-backend" }"#);
        assert_eq!(
            r.validate().unwrap(),
            OrchestratorCommand::StopAgent {
                name: "dev-backend".to_owned()
            }
        );
    }

    #[test]
    fn stop_agent_missing_name_is_rejected() {
        let r = req(r#"{ "action": "stop_agent" }"#);
        assert_eq!(
            r.validate(),
            Err(OrchestratorError::MissingField {
                action: "stop_agent".to_owned(),
                field: "name".to_owned(),
            })
        );
    }

    #[test]
    fn update_context_requires_a_body() {
        let ok =
            req(r##"{ "action": "update_agent_context", "name": "a", "context": "# new body" }"##);
        assert_eq!(
            ok.validate().unwrap(),
            OrchestratorCommand::UpdateAgentContext {
                name: "a".to_owned(),
                context: "# new body".to_owned(),
            }
        );

        let missing = req(r#"{ "action": "update_agent_context", "name": "a" }"#);
        assert_eq!(
            missing.validate(),
            Err(OrchestratorError::MissingField {
                action: "update_agent_context".to_owned(),
                field: "context".to_owned(),
            })
        );
    }

    #[test]
    fn create_skill_defaults_to_project_scope() {
        let r =
            req(r##"{ "action": "create_skill", "name": "deploy", "context": "# Deploy steps" }"##);
        assert_eq!(
            r.validate().unwrap(),
            OrchestratorCommand::CreateSkill {
                name: "deploy".to_owned(),
                content: "# Deploy steps".to_owned(),
                scope: SkillScope::Project,
            }
        );
    }

    #[test]
    fn create_skill_honours_explicit_scope_case_insensitively() {
        let r = req(
            r##"{ "action": "create_skill", "name": "deploy", "context": "body", "scope": "Global" }"##,
        );
        assert_eq!(
            r.validate().unwrap(),
            OrchestratorCommand::CreateSkill {
                name: "deploy".to_owned(),
                content: "body".to_owned(),
                scope: SkillScope::Global,
            }
        );
    }

    #[test]
    fn create_skill_missing_body_is_rejected() {
        let r = req(r#"{ "action": "create_skill", "name": "deploy" }"#);
        assert_eq!(
            r.validate(),
            Err(OrchestratorError::MissingField {
                action: "create_skill".to_owned(),
                field: "context".to_owned(),
            })
        );
    }

    #[test]
    fn create_skill_unknown_scope_is_rejected() {
        let r = req(
            r##"{ "action": "create_skill", "name": "deploy", "context": "body", "scope": "team" }"##,
        );
        assert_eq!(
            r.validate(),
            Err(OrchestratorError::UnknownScope {
                action: "create_skill".to_owned(),
                scope: "team".to_owned(),
            })
        );
    }

    #[test]
    fn unknown_action_is_rejected() {
        let r = req(r#"{ "action": "delete_everything", "name": "a" }"#);
        assert_eq!(
            r.validate(),
            Err(OrchestratorError::UnknownAction(
                "delete_everything".to_owned()
            ))
        );
    }

    #[test]
    fn blank_name_is_treated_as_missing() {
        let r = req(r#"{ "action": "stop_agent", "name": "   " }"#);
        assert!(matches!(
            r.validate(),
            Err(OrchestratorError::MissingField { .. })
        ));
    }
}