use crate::dag::{DagError, DagResult, FlowDag, NodeStatus, build_flow_dag};
use crate::models::{
    Context, Flow, FlowStatus, Job, JobStatus, Message, MessageFormatType, MessageStatus,
    Runner, TransportStatus,
};
use crate::storage::RedisDriver;

use serde::Serialize;
use serde_json::Value;
use std::collections::{HashMap, HashSet};
use std::sync::Arc;
use tokio::sync::Mutex;
use tokio::time::{Duration, sleep};

pub type BoxError = Box<dyn std::error::Error + Send + Sync>;

#[derive(Debug)]
struct InvalidJobStatusTransition {
    from: JobStatus,
    to: JobStatus,
}

impl std::fmt::Display for InvalidJobStatusTransition {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "Invalid job status transition: {:?} -> {:?}",
            self.from, self.to
        )
    }
}
impl std::error::Error for InvalidJobStatusTransition {}

#[derive(Debug)]
struct ValidationError {
    msg: String,
}
impl ValidationError {
    fn new(msg: impl Into<String>) -> Self {
        Self { msg: msg.into() }
    }
}
impl std::fmt::Display for ValidationError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "Validation error: {}", self.msg)
    }
}
impl std::error::Error for ValidationError {}

#[derive(Debug)]
struct PermissionDeniedError {
    actor_id: u32,
    context_id: u32,
    action: String,
}
impl std::fmt::Display for PermissionDeniedError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "Permission denied: actor {} cannot {} in context {}",
            self.actor_id, self.action, self.context_id
        )
    }
}
impl std::error::Error for PermissionDeniedError {}

#[derive(Debug)]
struct AlreadyExistsError {
    key: String,
}
impl std::fmt::Display for AlreadyExistsError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "Already exists: {}", self.key)
    }
}
impl std::error::Error for AlreadyExistsError {}

// -----------------------------
// Internal helpers
// -----------------------------

fn as_json(model: &impl Serialize) -> Result<Value, BoxError> {
    Ok(serde_json::to_value(model)?)
}

fn json_get_u32(v: &Value, key: &str) -> Result<u32, BoxError> {
    v.get(key)
        .and_then(|v| v.as_u64())
        .map(|x| x as u32)
        .ok_or_else(|| {
            ValidationError::new(format!("missing or invalid u32 field '{}'", key)).into()
        })
}

fn json_get_str(v: &Value, key: &str) -> Result<String, BoxError> {
    v.get(key)
        .and_then(|v| v.as_str())
        .map(|s| s.to_string())
        .ok_or_else(|| {
            ValidationError::new(format!("missing or invalid string field '{}'", key)).into()
        })
}

fn json_get_array(v: &Value, key: &str) -> Result<Vec<Value>, BoxError> {
    let arr = v
        .get(key)
        .and_then(|v| v.as_array())
        .ok_or_else(|| ValidationError::new(format!("missing or invalid array field '{}'", key)))?;
    Ok(arr.clone())
}

fn contains_key_not_found(e: &BoxError) -> bool {
    e.to_string().contains("Key not found")
}

fn has_duplicate_u32s(list: &Vec<Value>) -> bool {
    let mut seen = std::collections::HashSet::new();
    for it in list {
        if let Some(x) = it.as_u64() {
            if !seen.insert(x) {
                return true;
            }
        }
    }
    false
}

fn vec_u32_contains(list: &[Value], val: u32) -> bool {
    list.iter().any(|v| v.as_u64() == Some(val as u64))
}

// role = "admins" | "executors" | "readers"
fn context_has_role(ctx: &Context, role: &str, actor_id: u32) -> Result<bool, BoxError> {
    let v = as_json(ctx)?;
    let arr = v
        .get(role)
        .and_then(|r| r.as_array())
        .ok_or_else(|| ValidationError::new(format!("Context.{} missing or invalid", role)))?;
    Ok(arr.iter().any(|x| x.as_u64() == Some(actor_id as u64)))
}

// -----------------------------
// Validation helpers (minimal, spec-aligned)
// -----------------------------

fn validate_context(ctx: &Context) -> Result<(), BoxError> {
    let v = as_json(ctx)?;
    let id = json_get_u32(&v, "id")?;
    if id == 0 {
        return Err(ValidationError::new("Context.id must be > 0").into());
    }
    // admins required
    let admins = json_get_array(&v, "admins")?;
    if admins.is_empty() {
        return Err(ValidationError::new("Context.admins must not be empty").into());
    }
    Ok(())
}

// Actor was renamed to Runner - validate_actor is deprecated
// fn validate_actor(actor: &Actor) -> Result<(), BoxError> { ... }

fn validate_runner(_context_id: u32, runner: &Runner) -> Result<(), BoxError> {
    let v = as_json(runner)?;
    let id = json_get_u32(&v, "id")?;
    if id == 0 {
        return Err(ValidationError::new("Runner.id must be > 0").into());
    }
    let pubkey = json_get_str(&v, "pubkey")?;
    if pubkey.trim().is_empty() {
        return Err(ValidationError::new("Runner.pubkey must not be empty").into());
    }
    let topic = json_get_str(&v, "topic")?;
    if topic.trim().is_empty() {
        return Err(ValidationError::new("Runner.topic must not be empty").into());
    }
    // address presence is ensured by serde typing; no additional validation here
    Ok(())
}

fn validate_flow(context_id: u32, flow: &Flow) -> Result<(), BoxError> {
    let v = as_json(flow)?;
    let id = json_get_u32(&v, "id")?;
    if id == 0 {
        return Err(ValidationError::new("Flow.id must be > 0").into());
    }
    let ctx = json_get_u32(&v, "context_id")?;
    if ctx != context_id {
        return Err(ValidationError::new(format!(
            "Flow.context_id ({}) does not match path context_id ({})",
            ctx, context_id
        ))
        .into());
    }
    let jobs = json_get_array(&v, "jobs")?;
    if has_duplicate_u32s(&jobs) {
        return Err(ValidationError::new("Flow.jobs must not contain duplicates").into());
    }
    Ok(())
}

// Validation moved to Job model - use job.validate_required_fields() and job.validate_context()

fn validate_message(context_id: u32, msg: &Message) -> Result<(), BoxError> {
    let v = as_json(msg)?;
    let id = json_get_u32(&v, "id")?;
    if id == 0 {
        return Err(ValidationError::new("Message.id must be > 0").into());
    }
    let ctx = json_get_u32(&v, "context_id")?;
    if ctx != context_id {
        return Err(ValidationError::new(format!(
            "Message.context_id ({}) does not match path context_id ({})",
            ctx, context_id
        ))
        .into());
    }
    let body = json_get_str(&v, "message")?;
    if body.trim().is_empty() {
        return Err(ValidationError::new("Message.message must not be empty").into());
    }
    let t = json_get_u32(&v, "timeout")?;
    let ta = json_get_u32(&v, "timeout_ack")?;
    let tr = json_get_u32(&v, "timeout_result")?;
    if t == 0 || ta == 0 || tr == 0 {
        return Err(ValidationError::new(
            "Message timeouts (timeout|timeout_ack|timeout_result) must be > 0",
        )
        .into());
    }
    // Validate embedded jobs minimal consistency (caller/context match)
    let jobs = json_get_array(&v, "job")?;
    let msg_caller = json_get_u32(&v, "caller_id")?;
    for jv in jobs {
        if let Some(obj) = jv.as_object() {
            let mut jid = 0u32;
            if let Some(u) = obj.get("id").and_then(|x| x.as_u64()) {
                jid = u as u32;
            }
            if let (Some(jctx), Some(jcaller)) = (
                obj.get("context_id").and_then(|x| x.as_u64()),
                obj.get("caller_id").and_then(|x| x.as_u64()),
            ) {
                if jctx as u32 != context_id {
                    return Err(ValidationError::new(format!(
                        "Embedded Job {} context_id mismatch ({} != {})",
                        jid, jctx as u32, context_id
                    ))
                    .into());
                }
                if jcaller as u32 != msg_caller {
                    return Err(ValidationError::new(format!(
                        "Embedded Job {} caller_id mismatch ({} != {})",
                        jid, jcaller as u32, msg_caller
                    ))
                    .into());
                }
            }
        }
    }
    Ok(())
}

// -----------------------------
// Service API
// -----------------------------

#[derive(Clone)]
pub struct AppService {
    redis: Arc<RedisDriver>,
    schedulers: Arc<Mutex<HashSet<(u32, u32)>>>,
}

impl AppService {
    pub fn new(redis: RedisDriver) -> Self {
        Self {
            redis: Arc::new(redis),
            schedulers: Arc::new(Mutex::new(HashSet::new())),
        }
    }

    // -----------------------------
    // Context
    // -----------------------------
    pub async fn create_context(&self, ctx: Context) -> Result<Context, BoxError> {
        validate_context(&ctx)?;
        // id
        let v = as_json(&ctx)?;
        let context_id = json_get_u32(&v, "id")?;
        self.ensure_context_not_exists(context_id).await?;
        self.redis.save_context(&ctx).await?;
        Ok(ctx)
    }

    pub async fn load_context(&self, id: u32) -> Result<Context, BoxError> {
        let ctx = self.redis.load_context(id).await?;
        Ok(ctx)
    }

    // -----------------------------
    // Actor (deprecated - renamed to Runner)
    // -----------------------------
    // pub async fn create_actor(&self, actor: Actor) -> Result<Actor, BoxError> { ... }
    // pub async fn load_actor(&self, id: u32) -> Result<Actor, BoxError> { ... }

    // -----------------------------
    // Runner
    // -----------------------------
    pub async fn create_runner(&self, context_id: u32, runner: Runner) -> Result<Runner, BoxError> {
        validate_runner(context_id, &runner)?;
        let v = as_json(&runner)?;
        let id = json_get_u32(&v, "id")?;
        self.ensure_runner_not_exists(context_id, id).await?;
        self.redis.save_runner(context_id, &runner).await?;
        Ok(runner)
    }

    pub async fn load_runner(&self, context_id: u32, id: u32) -> Result<Runner, BoxError> {
        let runner = self.redis.load_runner(context_id, id).await?;
        Ok(runner)
    }

    // -----------------------------
    // Flow
    // -----------------------------
    pub async fn create_flow(&self, context_id: u32, flow: Flow) -> Result<Flow, BoxError> {
        validate_flow(context_id, &flow)?;

        // Permission: require that flow.caller_id is admin in the context
        let v = as_json(&flow)?;
        let fid = json_get_u32(&v, "id")?;
        let caller_id = json_get_u32(&v, "caller_id")?;
        self.require_admin(context_id, caller_id, "create flow")
            .await?;

        self.ensure_flow_not_exists(context_id, fid).await?;
        // Require that the context exists
        let _ = self.redis.load_context(context_id).await?;
        self.redis.save_flow(context_id, &flow).await?;
        Ok(flow)
    }

    pub async fn load_flow(&self, context_id: u32, id: u32) -> Result<Flow, BoxError> {
        let flow = self.redis.load_flow(context_id, id).await?;
        Ok(flow)
    }

    pub async fn flow_dag(&self, context_id: u32, flow_id: u32) -> DagResult<FlowDag> {
        build_flow_dag(&self.redis, context_id, flow_id).await
    }

    /// Start a background scheduler for a flow.
    /// - Ticks every 1 second.
    /// - Sets Flow status to Started immediately.
    /// - Dispatches jobs whose dependencies are Finished: creates a Message and LPUSHes its key into msg_out,
    ///   and marks the job status to Dispatched.
    /// - When all jobs are Finished sets Flow to Finished; if any job is Error sets Flow to Error.
    /// Returns:
    ///   - Ok(true) if a scheduler was started
    ///   - Ok(false) if a scheduler was already running for this (context_id, flow_id)
    pub async fn flow_start(&self, context_id: u32, flow_id: u32) -> Result<bool, BoxError> {
        // Ensure flow exists (and load caller_id)
        let flow = self.redis.load_flow(context_id, flow_id).await?;
        let caller_id = flow.caller_id();

        // Try to register this flow in the active scheduler set
        {
            let mut guard = self.schedulers.lock().await;
            if !guard.insert((context_id, flow_id)) {
                // Already running
                return Ok(false);
            }
        }

        // Clone resources for background task
        let redis = self.redis.clone();
        let schedulers = self.schedulers.clone();

        // Set Flow status to Started
        let _ = redis
            .update_flow_status(context_id, flow_id, FlowStatus::Started)
            .await;

        tokio::spawn(async move {
            // Background loop
            loop {
                // Build DAG from flow
                let dag = match build_flow_dag(&redis, context_id, flow_id).await {
                    Ok(d) => d,
                    Err(_) => break, // Flow missing or error
                };

                // Get ready nodes (dependencies satisfied, not yet dispatched)
                let ready_node_ids = match dag.ready_jobs() {
                    Ok(ids) => ids,
                    Err(_) => {
                        // DAG error (e.g., failed job), mark flow as error and exit
                        let _ = redis
                            .update_flow_status(context_id, flow_id, FlowStatus::Error)
                            .await;
                        break;
                    }
                };

                // Dispatch ready nodes
                for node_id in ready_node_ids {
                    let node = match dag.nodes.get(&node_id) {
                        Some(n) => n,
                        None => continue,
                    };

                    // Load the job data
                    let job = match redis.load_job(context_id, caller_id, node_id).await {
                        Ok(j) => j,
                        Err(_) => continue,
                    };

                    // Build Message with FlowNode for routing
                    let ts = crate::time::current_timestamp();
                    let msg_id: u32 = node_id; // Use node_id as message_id

                    let message = Message {
                        id: msg_id,
                        caller_id: job.caller_id.parse().unwrap_or(0),
                        context_id,
                        flow_id,
                        message: "job.run".to_string(),
                        message_type: job.executor.clone(),
                        message_format_type: MessageFormatType::Text,
                        timeout: job.timeout as u32,
                        timeout_ack: 10,
                        timeout_result: job.timeout as u32,
                        transport_id: None,
                        transport_status: None,
                        nodes: vec![node.clone()], // Include FlowNode for routing
                        job: vec![job.clone()],
                        logs: Vec::new(),
                        created_at: ts,
                        updated_at: ts,
                        status: MessageStatus::Dispatched,
                    };

                    // Persist the message and enqueue it
                    if redis.save_message(context_id, &message).await.is_ok() {
                        let caller_id_u32 = job.caller_id.parse::<u32>().unwrap_or(0);
                        let _ = redis.enqueue_msg_out(context_id, caller_id_u32, msg_id);
                        // TODO: Mark node as Dispatched in DAG and persist
                        // For now, the node status is tracked in memory only
                    }
                }

                // Check if flow is complete
                let all_finished = dag.completed.len() == dag.nodes.len();
                let any_error = dag.failed_job.is_some();

                if any_error {
                    let _ = redis
                        .update_flow_status(context_id, flow_id, FlowStatus::Error)
                        .await;
                    break;
                }
                if all_finished {
                    let _ = redis
                        .update_flow_status(context_id, flow_id, FlowStatus::Finished)
                        .await;
                    break;
                }

                sleep(Duration::from_secs(1)).await;
            }

            // Remove from active schedulers set
            let mut guard = schedulers.lock().await;
            guard.remove(&(context_id, flow_id));
        });

        Ok(true)
    }

    /// Execute a flow: compute DAG, create Message entries for ready jobs, and enqueue their keys to msg_out.
    /// Returns the list of enqueued message keys ("message:{caller_id}:{id}") in deterministic order (by job id).
    pub async fn flow_execute(&self, context_id: u32, flow_id: u32) -> DagResult<Vec<String>> {
        let dag = build_flow_dag(&self.redis, context_id, flow_id).await?;
        let mut ready = dag.ready_jobs()?;
        ready.sort_unstable();

        let mut queued: Vec<String> = Vec::with_capacity(ready.len());
        for jid in ready {
            // Load the concrete Job
            let job = self
                .redis
                .load_job(context_id, dag.caller_id, jid)
                .await
                .map_err(DagError::from)?;

            // Build a Message that embeds this job
            let ts = crate::time::current_timestamp();
            let msg_id: u32 = job.id.parse().unwrap_or(0); // deterministic; adjust strategy later if needed

            let message = Message {
                id: msg_id,
                caller_id: job.caller_id.parse().unwrap_or(0),
                context_id,
                flow_id, // Add flow_id for DAG tracking
                message: "job.run".to_string(),
                message_type: job.executor.clone(),
                message_format_type: MessageFormatType::Text,
                timeout: job.timeout as u32,
                timeout_ack: 10,
                timeout_result: job.timeout as u32,
                transport_id: None,
                transport_status: None,
                nodes: Vec::new(), // TODO: Add FlowNode from DAG
                job: vec![job.clone()],
                logs: Vec::new(),
                created_at: ts,
                updated_at: ts,
                status: MessageStatus::Dispatched,
            };

            // Persist the Message and enqueue its key to the outbound queue
            let _ = self
                .create_message(context_id, message)
                .await
                .map_err(DagError::from)?;

            let caller_id_u32 = job.caller_id.parse::<u32>().unwrap_or(0);
            self.redis
                .enqueue_msg_out(context_id, caller_id_u32, msg_id)
                .await
                .map_err(DagError::from)?;

            let key = format!("message:{}:{}", caller_id_u32, msg_id);
            queued.push(key);
        }

        Ok(queued)
    }

    // -----------------------------
    // Job
    // -----------------------------
    pub async fn create_job(&self, context_id: u32, job: Job) -> Result<Job, BoxError> {
        // Validation removed - Job validation now handled at creation time
        let v = as_json(&job)?;
        let id = json_get_u32(&v, "id")?;
        let caller_id = json_get_u32(&v, "caller_id")?;
        self.ensure_job_not_exists(context_id, caller_id, id)
            .await?;
        self.redis.save_job(context_id, &job).await?;
        Ok(job)
    }

    pub async fn load_job(
        &self,
        context_id: u32,
        caller_id: u32,
        id: u32,
    ) -> Result<Job, BoxError> {
        let job = self.redis.load_job(context_id, caller_id, id).await?;
        Ok(job)
    }

    /// Update a job status with transition validation.
    ///
    /// Allowed transitions:
    /// - Dispatched -> WaitingForPrerequisites | Started | Error
    /// - WaitingForPrerequisites -> Started | Error
    /// - Started -> Finished | Error
    /// - Finished, Error -> terminal (no transitions)
    ///
    /// If the new status equals the current status, this is a no-op.
    /// Update node status in the DAG with transition validation.
    /// 
    /// Allowed transitions:
    /// - Pending -> Ready | Dispatched | Cancelled
    /// - Ready -> Dispatched | Cancelled
    /// - Dispatched -> Running | Failed | Cancelled
    /// - Running -> Completed | Failed | Cancelled
    /// - Completed, Failed, Cancelled -> terminal (no transitions)
    ///
    /// If the new status equals the current status, this is a no-op (idempotent).
    pub async fn update_node_status(
        &self,
        context_id: u32,
        executor_id: u32,
        flow_id: u32,
        node_id: u32,
        new_status: NodeStatus,
    ) -> Result<(), BoxError> {
        self.require_executor(context_id, executor_id, "update node status")
            .await?;
        
        // Load the DAG
        let mut dag = build_flow_dag(&self.redis, context_id, flow_id).await?;
        
        // Get current node status
        let node = dag.nodes.get(&node_id)
            .ok_or_else(|| format!("Node {} not found in flow {}", node_id, flow_id))?;
        let current = node.node_status.clone();
        
        if new_status == current {
            // Idempotent: don't touch storage if no change
            return Ok(());
        }
        
        // Validate state transition
        let allowed = match current {
            NodeStatus::Pending => matches!(
                new_status,
                NodeStatus::Ready | NodeStatus::Dispatched | NodeStatus::Cancelled
            ),
            NodeStatus::Ready => matches!(
                new_status,
                NodeStatus::Dispatched | NodeStatus::Cancelled
            ),
            NodeStatus::Dispatched => matches!(
                new_status,
                NodeStatus::Running | NodeStatus::Failed | NodeStatus::Cancelled
            ),
            NodeStatus::Running => matches!(
                new_status,
                NodeStatus::Completed | NodeStatus::Failed | NodeStatus::Cancelled
            ),
            NodeStatus::Completed | NodeStatus::Failed | NodeStatus::Cancelled => false,
        };
        
        if !allowed {
            return Err(format!(
                "Invalid node status transition from {:?} to {:?}",
                current, new_status
            ).into());
        }
        
        // Update the node status
        if let Some(node) = dag.nodes.get_mut(&node_id) {
            node.node_status = new_status;
            
            // Persist the updated DAG
            // TODO: Implement DAG persistence
            // self.redis.save_flow_dag(context_id, flow_id, &dag).await?;
        }
        
        Ok(())
    }
    /// Bypass-permission variant to update node status with transition validation.
    /// This skips the executor permission check but enforces the same state transition rules.
    pub async fn update_node_status_unchecked(
        &self,
        context_id: u32,
        flow_id: u32,
        node_id: u32,
        new_status: NodeStatus,
    ) -> Result<(), BoxError> {
        // Load the DAG
        let mut dag = build_flow_dag(&self.redis, context_id, flow_id).await?;
        
        // Get current node status
        let node = dag.nodes.get(&node_id)
            .ok_or_else(|| format!("Node {} not found in flow {}", node_id, flow_id))?;
        let current = node.node_status.clone();
        
        if new_status == current {
            // Idempotent: don't touch storage if no change
            return Ok(());
        }
        
        // Validate state transition
        let allowed = match current {
            NodeStatus::Pending => matches!(
                new_status,
                NodeStatus::Ready | NodeStatus::Dispatched | NodeStatus::Cancelled
            ),
            NodeStatus::Ready => matches!(
                new_status,
                NodeStatus::Dispatched | NodeStatus::Cancelled
            ),
            NodeStatus::Dispatched => matches!(
                new_status,
                NodeStatus::Running | NodeStatus::Failed | NodeStatus::Cancelled
            ),
            NodeStatus::Running => matches!(
                new_status,
                NodeStatus::Completed | NodeStatus::Failed | NodeStatus::Cancelled
            ),
            NodeStatus::Completed | NodeStatus::Failed | NodeStatus::Cancelled => false,
        };
        
        if !allowed {
            return Err(format!(
                "Invalid node status transition from {:?} to {:?}",
                current, new_status
            ).into());
        }
        
        // Update the node status
        if let Some(node) = dag.nodes.get_mut(&node_id) {
            node.node_status = new_status.clone();
            
            // Update DAG runtime state for ready_jobs() to work correctly
            match new_status {
                NodeStatus::Dispatched | NodeStatus::Running => {
                    dag.started.insert(node_id);
                }
                NodeStatus::Completed => {
                    dag.started.insert(node_id);
                    dag.completed.insert(node_id);
                }
                NodeStatus::Failed => {
                    dag.started.insert(node_id);
                    dag.failed_job = Some(node_id);
                }
                _ => {}
            }
            
            // Persist the updated DAG
            // TODO: Implement DAG persistence to Redis
            // For now, the DAG is rebuilt each time, so runtime state is lost
            // self.redis.save_flow_dag(context_id, flow_id, &dag).await?;
        }
        
        Ok(())
    }

    // -----------------------------
    // Message
    // -----------------------------
    pub async fn create_message(
        &self,
        context_id: u32,
        message: Message,
    ) -> Result<Message, BoxError> {
        validate_message(context_id, &message)?;
        let v = as_json(&message)?;
        let id = json_get_u32(&v, "id")?;
        let caller_id = json_get_u32(&v, "caller_id")?;
        self.ensure_message_not_exists(context_id, caller_id, id)
            .await?;
        self.redis.save_message(context_id, &message).await?;
        Ok(message)
    }

    pub async fn load_message(
        &self,
        context_id: u32,
        caller_id: u32,
        id: u32,
    ) -> Result<Message, BoxError> {
        let msg = self.redis.load_message(context_id, caller_id, id).await?;
        Ok(msg)
    }

    pub async fn update_flow_status(
        &self,
        context_id: u32,
        requestor_id: u32,
        id: u32,
        new_status: FlowStatus,
    ) -> Result<(), BoxError> {
        self.require_admin(context_id, requestor_id, "update flow status")
            .await?;
        let flow = self.redis.load_flow(context_id, id).await?;
        let v = as_json(&flow)?;
        let cur_raw = v
            .get("status")
            .cloned()
            .unwrap_or(Value::String("Dispatched".to_string()));

        let cur = match cur_raw {
            Value::String(s) if s == "Dispatched" => FlowStatus::Dispatched,
            Value::String(s) if s == "Started" => FlowStatus::Started,
            Value::String(s) if s == "Error" => FlowStatus::Error,
            Value::String(s) if s == "Finished" => FlowStatus::Finished,
            _ => FlowStatus::Dispatched,
        };

        if cur == new_status {
            return Ok(());
        }

        let allowed = match cur {
            FlowStatus::Created => matches!(new_status, FlowStatus::Dispatched | FlowStatus::Error),
            FlowStatus::Dispatched => matches!(new_status, FlowStatus::Started | FlowStatus::Error),
            FlowStatus::Started => matches!(new_status, FlowStatus::Finished | FlowStatus::Error),
            FlowStatus::Finished | FlowStatus::Error => false,
        };
        if !allowed {
            return Err(ValidationError::new(format!(
                "Invalid flow status transition: {:?} -> {:?}",
                cur, new_status
            ))
            .into());
        }

        self.redis
            .update_flow_status(context_id, id, new_status)
            .await
    }

    pub async fn update_message_status(
        &self,
        context_id: u32,
        caller_id: u32,
        id: u32,
        new_status: MessageStatus,
    ) -> Result<(), BoxError> {
        let msg = self.redis.load_message(context_id, caller_id, id).await?;
        let v = as_json(&msg)?;
        let cur_raw = v
            .get("status")
            .cloned()
            .unwrap_or(Value::String("Dispatched".to_string()));

        let cur = match cur_raw {
            Value::String(s) if s == "Dispatched" => MessageStatus::Dispatched,
            Value::String(s) if s == "Acknowledged" => MessageStatus::Acknowledged,
            Value::String(s) if s == "Error" => MessageStatus::Error,
            Value::String(s) if s == "Processed" => MessageStatus::Processed,
            _ => MessageStatus::Dispatched,
        };

        if cur == new_status {
            return Ok(());
        }

        let allowed = match cur {
            MessageStatus::Dispatched => {
                matches!(
                    new_status,
                    MessageStatus::Acknowledged | MessageStatus::Error
                )
            }
            MessageStatus::Acknowledged => {
                matches!(new_status, MessageStatus::Processed | MessageStatus::Error)
            }
            MessageStatus::Processed | MessageStatus::Error => false,
        };
        if !allowed {
            return Err(ValidationError::new(format!(
                "Invalid message status transition: {:?} -> {:?}",
                cur, new_status
            ))
            .into());
        }

        self.redis
            .update_message_status(context_id, caller_id, id, new_status)
            .await
    }

    pub async fn update_message_transport(
        &self,
        context_id: u32,
        caller_id: u32,
        id: u32,
        transport_id: Option<String>,
        transport_status: Option<TransportStatus>,
    ) -> Result<(), BoxError> {
        // Ensure message exists (provides clearer error)
        let _ = self.redis.load_message(context_id, caller_id, id).await?;
        self.redis
            .update_message_transport(context_id, caller_id, id, transport_id, transport_status)
            .await
    }

    pub async fn update_flow_env_vars_merge(
        &self,
        context_id: u32,
        requestor_id: u32,
        flow_id: u32,
        patch: HashMap<String, String>,
    ) -> Result<(), BoxError> {
        self.require_admin(context_id, requestor_id, "update flow env_vars")
            .await?;
        // Ensure flow exists
        let _ = self.redis.load_flow(context_id, flow_id).await?;
        self.redis
            .update_flow_env_vars_merge(context_id, flow_id, patch)
            .await
    }

    pub async fn update_flow_result_merge(
        &self,
        context_id: u32,
        requestor_id: u32,
        flow_id: u32,
        patch: HashMap<String, String>,
    ) -> Result<(), BoxError> {
        self.require_admin(context_id, requestor_id, "update flow result")
            .await?;
        let _ = self.redis.load_flow(context_id, flow_id).await?;
        self.redis
            .update_flow_result_merge(context_id, flow_id, patch)
            .await
    }

    pub async fn update_flow_jobs_add_remove(
        &self,
        context_id: u32,
        requestor_id: u32,
        flow_id: u32,
        add: Vec<u32>,
        remove: Vec<u32>,
    ) -> Result<(), BoxError> {
        self.require_admin(context_id, requestor_id, "update flow jobs")
            .await?;
        let flow = self.redis.load_flow(context_id, flow_id).await?;
        let mut set: std::collections::BTreeSet<u32> = flow.jobs().iter().copied().collect();
        for a in add {
            set.insert(a);
        }
        for r in remove {
            set.remove(&r);
        }
        let new_jobs: Vec<u32> = set.into_iter().collect();
        self.redis
            .update_flow_jobs_set(context_id, flow_id, new_jobs)
            .await
    }

    pub async fn update_job_env_vars_merge(
        &self,
        context_id: u32,
        requestor_id: u32,
        caller_id: u32,
        job_id: u32,
        patch: HashMap<String, String>,
    ) -> Result<(), BoxError> {
        self.require_admin(context_id, requestor_id, "update job env_vars")
            .await?;
        let _ = self.redis.load_job(context_id, caller_id, job_id).await?;
        self.redis
            .update_job_env_vars_merge(context_id, caller_id, job_id, patch)
            .await
    }

    pub async fn update_job_result_merge(
        &self,
        context_id: u32,
        requestor_id: u32,
        caller_id: u32,
        job_id: u32,
        patch: HashMap<String, String>,
    ) -> Result<(), BoxError> {
        // Allow if admin OR executor
        let ctx = self.redis.load_context(context_id).await?;
        let is_admin = context_has_role(&ctx, "admins", requestor_id)?;
        let is_exec = context_has_role(&ctx, "executors", requestor_id)?;
        if !(is_admin || is_exec) {
            return Err(Box::new(PermissionDeniedError {
                actor_id: requestor_id,
                context_id,
                action: "update job result".to_string(),
            }));
        }
        let _ = self.redis.load_job(context_id, caller_id, job_id).await?;
        self.redis
            .update_job_result_merge(context_id, caller_id, job_id, patch)
            .await
    }

    /// Bypass-permission variant to merge into a job's result field.
    /// Intended for internal router/scheduler use where no actor identity is present.
    pub async fn update_job_result_merge_unchecked(
        &self,
        context_id: u32,
        caller_id: u32,
        job_id: u32,
        patch: HashMap<String, String>,
    ) -> Result<(), BoxError> {
        // Ensure job exists, then write directly
        let _ = self.redis.load_job(context_id, caller_id, job_id).await?;
        self.redis
            .update_job_result_merge(context_id, caller_id, job_id, patch)
            .await
    }

    pub async fn append_message_logs(
        &self,
        context_id: u32,
        caller_id: u32,
        id: u32,
        new_logs: Vec<String>,
    ) -> Result<(), BoxError> {
        let _ = self.redis.load_message(context_id, caller_id, id).await?;
        self.redis
            .append_message_logs(context_id, caller_id, id, new_logs)
            .await
    }
}

// -----------------------------
// Existence checks (strict create) and permissions
// -----------------------------
impl AppService {
    async fn ensure_context_not_exists(&self, id: u32) -> Result<(), BoxError> {
        match self.redis.load_context(id).await {
            Ok(_) => Err(Box::new(AlreadyExistsError {
                key: format!("context:{}", id),
            })),
            Err(e) => {
                if contains_key_not_found(&e) {
                    Ok(())
                } else {
                    Err(e)
                }
            }
        }
    }



    async fn ensure_runner_not_exists(&self, db: u32, id: u32) -> Result<(), BoxError> {
        match self.redis.load_runner(db, id).await {
            Ok(_) => Err(Box::new(AlreadyExistsError {
                key: format!("runner:{}", id),
            })),
            Err(e) => {
                if contains_key_not_found(&e) {
                    Ok(())
                } else {
                    Err(e)
                }
            }
        }
    }

    async fn ensure_flow_not_exists(&self, db: u32, id: u32) -> Result<(), BoxError> {
        match self.redis.load_flow(db, id).await {
            Ok(_) => Err(Box::new(AlreadyExistsError {
                key: format!("flow:{}", id),
            })),
            Err(e) => {
                if contains_key_not_found(&e) {
                    Ok(())
                } else {
                    Err(e)
                }
            }
        }
    }

    async fn ensure_job_not_exists(
        &self,
        db: u32,
        caller_id: u32,
        id: u32,
    ) -> Result<(), BoxError> {
        match self.redis.load_job(db, caller_id, id).await {
            Ok(_) => Err(Box::new(AlreadyExistsError {
                key: format!("job:{}:{}", caller_id, id),
            })),
            Err(e) => {
                if contains_key_not_found(&e) {
                    Ok(())
                } else {
                    Err(e)
                }
            }
        }
    }

    async fn ensure_message_not_exists(
        &self,
        db: u32,
        caller_id: u32,
        id: u32,
    ) -> Result<(), BoxError> {
        match self.redis.load_message(db, caller_id, id).await {
            Ok(_) => Err(Box::new(AlreadyExistsError {
                key: format!("message:{}:{}", caller_id, id),
            })),
            Err(e) => {
                if contains_key_not_found(&e) {
                    Ok(())
                } else {
                    Err(e)
                }
            }
        }
    }

    async fn require_admin(
        &self,
        context_id: u32,
        actor_id: u32,
        action: &str,
    ) -> Result<(), BoxError> {
        let ctx = self.redis.load_context(context_id).await?;
        let ok = context_has_role(&ctx, "admins", actor_id)?;
        if !ok {
            return Err(Box::new(PermissionDeniedError {
                actor_id,
                context_id,
                action: action.to_string(),
            }));
        }
        Ok(())
    }

    async fn require_executor(
        &self,
        context_id: u32,
        actor_id: u32,
        action: &str,
    ) -> Result<(), BoxError> {
        let ctx = self.redis.load_context(context_id).await?;
        let ok = context_has_role(&ctx, "executors", actor_id)?;
        if !ok {
            return Err(Box::new(PermissionDeniedError {
                actor_id,
                context_id,
                action: action.to_string(),
            }));
        }
        Ok(())
    }
}

/// Router/helper wrappers exposed on AppService so background tasks don't need direct Redis access.
impl AppService {
    /// Block-pop from the per-context msg_out queue with a timeout (seconds).
    /// Returns Some(message_key) like "message:{caller_id}:{id}" or None on timeout.
    pub async fn brpop_msg_out(
        &self,
        context_id: u32,
        timeout_secs: usize,
    ) -> Result<Option<String>, BoxError> {
        self.redis.brpop_msg_out(context_id, timeout_secs).await
    }

    /// Scan all runner:* in the given context and return deserialized Runner entries.
    pub async fn scan_runners(&self, context_id: u32) -> Result<Vec<Runner>, BoxError> {
        self.redis.scan_runners(context_id).await
    }

    /// Correlation map: store mapping from inner supervisor JSON-RPC id to context/caller/job/message.
    pub async fn supcorr_set(
        &self,
        inner_id: u64,
        context_id: u32,
        caller_id: u32,
        job_id: u32,
        message_id: u32,
    ) -> Result<(), BoxError> {
        self.redis
            .supcorr_set(inner_id, context_id, caller_id, job_id, message_id)
            .await
            .map_err(Into::into)
    }

    /// Correlation map: load mapping by inner supervisor JSON-RPC id.
    pub async fn supcorr_get(
        &self,
        inner_id: u64,
    ) -> Result<Option<(u32, u32, u32, u32)>, BoxError> {
        self.redis.supcorr_get(inner_id).await.map_err(Into::into)
    }

    /// Correlation map: delete mapping by inner supervisor JSON-RPC id.
    pub async fn supcorr_del(&self, inner_id: u64) -> Result<(), BoxError> {
        self.redis.supcorr_del(inner_id).await.map_err(Into::into)
    }
}

/// Auto-discovery helpers for contexts (wrappers over RedisDriver)
impl AppService {
    pub async fn list_context_ids(&self) -> Result<Vec<u32>, BoxError> {
        self.redis.list_context_ids().await
    }
}