use async_trait::async_trait;
use serde::{Deserialize, Serialize};
use serde_json::{json, Value};
use sqlx::PgPool;
use std::sync::Arc;
use uuid::Uuid;

use crate::plugins::{
    hooks::HookContext, manager::PluginSystem, Plugin, PluginError, PluginMetadata, PluginScope,
};

pub struct FederationPlugin;

impl FederationPlugin {
    pub fn new() -> Self {
        Self
    }
}

#[async_trait]
impl Plugin for FederationPlugin {
    fn metadata(&self) -> PluginMetadata {
        PluginMetadata {
            name: "federation",
            version: "1.0.0",
            description: "Multi-community federation and cross-instance collaboration",
            is_core: false,
            scope: PluginScope::Global,
            default_enabled: false,
            settings_schema: Some(json!({
                "type": "object",
                "properties": {
                    "allow_incoming_requests": {"type": "boolean", "default": true},
                    "min_trust_level": {"type": "integer", "default": 2},
                    "sync_interval_minutes": {"type": "integer", "default": 15}
                }
            })),
        }
    }

    fn register(&self, system: &mut PluginSystem) {
        // Hook: Sync federated proposals periodically
        system.add_action(
            "cron.every_15_minutes",
            "federation".to_string(),
            50,
            Arc::new(|ctx: HookContext, _payload: Value| {
                Box::pin(async move {
                    FederationService::sync_all_federations(&ctx.pool).await?;
                    Ok(())
                })
            }),
        );

        // Hook: Share proposal when created in federated community
        system.add_action(
            "proposal.created",
            "federation".to_string(),
            100,
            Arc::new(|ctx: HookContext, payload: Value| {
                Box::pin(async move {
                    if let Some(proposal_id) = payload
                        .get("proposal_id")
                        .and_then(|v| v.as_str())
                        .and_then(|s| Uuid::parse_str(s).ok())
                    {
                        FederationService::share_proposal_if_federated(&ctx.pool, proposal_id)
                            .await?;
                    }
                    Ok(())
                })
            }),
        );

        // Hook: Broadcast decision results
        system.add_action(
            "proposal.decided",
            "federation".to_string(),
            100,
            Arc::new(|ctx: HookContext, payload: Value| {
                Box::pin(async move {
                    if let Some(proposal_id) = payload
                        .get("proposal_id")
                        .and_then(|v| v.as_str())
                        .and_then(|s| Uuid::parse_str(s).ok())
                    {
                        FederationService::broadcast_decision(&ctx.pool, proposal_id).await?;
                    }
                    Ok(())
                })
            }),
        );
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FederatedInstance {
    pub id: Uuid,
    pub instance_url: String,
    pub instance_name: String,
    pub status: String,
    pub trust_level: i32,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CommunityFederation {
    pub id: Uuid,
    pub local_community_id: Uuid,
    pub remote_instance_id: Uuid,
    pub remote_community_id: Uuid,
    pub remote_community_name: Option<String>,
    pub status: String,
}

pub struct FederationService;

impl FederationService {
    /// Register a new federated instance
    pub async fn register_instance(
        pool: &PgPool,
        url: &str,
        name: &str,
        description: Option<&str>,
        public_key: Option<&str>,
    ) -> Result<Uuid, PluginError> {
        let instance_id: Uuid =
            sqlx::query_scalar("SELECT register_federated_instance($1, $2, $3, $4)")
                .bind(url)
                .bind(name)
                .bind(description)
                .bind(public_key)
                .fetch_one(pool)
                .await?;

        Ok(instance_id)
    }

    /// Create a federation between communities
    pub async fn create_federation(
        pool: &PgPool,
        local_community_id: Uuid,
        remote_instance_id: Uuid,
        remote_community_id: Uuid,
        remote_community_name: &str,
        sync_direction: &str,
    ) -> Result<Uuid, PluginError> {
        let federation_id: Uuid = sqlx::query_scalar(
            "SELECT create_community_federation($1, $2, $3, $4, $5::sync_direction)",
        )
        .bind(local_community_id)
        .bind(remote_instance_id)
        .bind(remote_community_id)
        .bind(remote_community_name)
        .bind(sync_direction)
        .fetch_one(pool)
        .await?;

        Ok(federation_id)
    }

    /// Approve a federation locally
    pub async fn approve_federation(
        pool: &PgPool,
        federation_id: Uuid,
        _approved_by: Uuid,
    ) -> Result<(), PluginError> {
        sqlx::query!(
            r#"UPDATE community_federations SET 
                approved_locally = true,
                status = CASE WHEN approved_remotely THEN 'active'::federation_status ELSE status END,
                updated_at = NOW()
            WHERE id = $1"#,
            federation_id
        )
        .execute(pool)
        .await?;

        sqlx::query!(
            r#"INSERT INTO federation_sync_log (federation_id, operation_type, direction, success)
            VALUES ($1, 'local_approval', 'push', true)"#,
            federation_id
        )
        .execute(pool)
        .await?;

        Ok(())
    }

    /// Sync all active federations
    pub async fn sync_all_federations(pool: &PgPool) -> Result<i32, PluginError> {
        let federations = sqlx::query!(
            r#"SELECT cf.id, cf.local_community_id, cf.remote_instance_id,
                fi.instance_url, cf.sync_direction::text AS "sync_direction!"
            FROM community_federations cf
            JOIN federated_instances fi ON fi.id = cf.remote_instance_id
            WHERE cf.status = 'active' AND fi.status = 'active'"#
        )
        .fetch_all(pool)
        .await?;

        let mut synced = 0;
        for fed in federations {
            // In a real implementation, this would make HTTP requests to remote instances
            // For now, just log the sync attempt
            let start = std::time::Instant::now();

            sqlx::query(
                r#"INSERT INTO federation_sync_log 
                    (federation_id, instance_id, operation_type, direction, success, duration_ms)
                VALUES ($1, $2, 'scheduled_sync', $3::sync_direction, true, $4)"#,
            )
            .bind(fed.id)
            .bind(fed.remote_instance_id)
            .bind(&fed.sync_direction)
            .bind(start.elapsed().as_millis() as i32)
            .execute(pool)
            .await?;

            sqlx::query!(
                "UPDATE federated_instances SET last_sync_at = NOW(), total_syncs = total_syncs + 1 WHERE id = $1",
                fed.remote_instance_id
            )
            .execute(pool)
            .await?;

            synced += 1;
        }

        Ok(synced)
    }

    /// Share a proposal to federated communities
    pub async fn share_proposal_if_federated(
        pool: &PgPool,
        proposal_id: Uuid,
    ) -> Result<(), PluginError> {
        // Get the proposal's community
        let proposal = sqlx::query!(
            "SELECT community_id FROM proposals WHERE id = $1",
            proposal_id
        )
        .fetch_optional(pool)
        .await?;

        let Some(proposal) = proposal else {
            return Ok(());
        };

        // Check for active federations that sync proposals
        let federations = sqlx::query!(
            r#"SELECT id, remote_instance_id, remote_community_id
            FROM community_federations
            WHERE local_community_id = $1 
              AND status = 'active' 
              AND sync_proposals = true
              AND sync_direction IN ('push', 'bidirectional')"#,
            proposal.community_id
        )
        .fetch_all(pool)
        .await?;

        for fed in federations {
            // Create federated proposal record
            sqlx::query!(
                r#"INSERT INTO federated_proposals 
                    (federation_id, local_proposal_id, remote_proposal_id, is_origin_local)
                VALUES ($1, $2, $2, true)
                ON CONFLICT DO NOTHING"#,
                fed.id,
                proposal_id
            )
            .execute(pool)
            .await?;
        }

        Ok(())
    }

    /// Broadcast decision to federated communities
    pub async fn broadcast_decision(pool: &PgPool, proposal_id: Uuid) -> Result<(), PluginError> {
        // Find federated proposal
        let federated = sqlx::query!(
            r#"SELECT fp.id, fp.federation_id
            FROM federated_proposals fp
            WHERE fp.local_proposal_id = $1"#,
            proposal_id
        )
        .fetch_all(pool)
        .await?;

        for fp in federated {
            // Get local vote results
            let results = sqlx::query!(
                r#"SELECT COUNT(*)::int AS total_votes
                FROM votes WHERE proposal_id = $1"#,
                proposal_id
            )
            .fetch_one(pool)
            .await?;

            // Create or update federated decision
            sqlx::query!(
                r#"INSERT INTO federated_decisions 
                    (federated_proposal_id, decision_type, outcome, total_votes, is_final)
                VALUES ($1, 'vote', 'pending', $2, false)
                ON CONFLICT DO NOTHING"#,
                fp.id,
                results.total_votes.unwrap_or(0)
            )
            .execute(pool)
            .await?;
        }

        Ok(())
    }

    /// Get federation statistics for a community
    pub async fn get_stats(pool: &PgPool, community_id: Uuid) -> Result<Value, PluginError> {
        let stats = sqlx::query!("SELECT * FROM get_federation_stats($1)", community_id)
            .fetch_one(pool)
            .await?;

        Ok(json!({
            "total_federations": stats.total_federations,
            "active_federations": stats.active_federations,
            "federated_proposals": stats.federated_proposals,
            "total_syncs": stats.total_syncs,
            "last_sync": stats.last_sync
        }))
    }

    /// Get all instances
    pub async fn get_instances(pool: &PgPool) -> Result<Vec<FederatedInstance>, PluginError> {
        let instances = sqlx::query_as!(
            FederatedInstance,
            r#"SELECT id, instance_url, instance_name, status::text AS "status!", trust_level
            FROM federated_instances ORDER BY instance_name"#
        )
        .fetch_all(pool)
        .await?;

        Ok(instances)
    }

    /// Get federations for a community
    pub async fn get_community_federations(
        pool: &PgPool,
        community_id: Uuid,
    ) -> Result<Vec<CommunityFederation>, PluginError> {
        let federations = sqlx::query_as!(
            CommunityFederation,
            r#"SELECT id, local_community_id, remote_instance_id, remote_community_id,
                remote_community_name, status::text AS "status!"
            FROM community_federations
            WHERE local_community_id = $1"#,
            community_id
        )
        .fetch_all(pool)
        .await?;

        Ok(federations)
    }

    /// Submit a federation request (handles incoming requests from other instances)
    pub async fn request_federation(
        pool: &PgPool,
        from_instance_url: &str,
        from_community_name: &str,
        to_community_id: Uuid,
        message: Option<&str>,
    ) -> Result<Uuid, PluginError> {
        let request_id = sqlx::query_scalar!(
            r#"INSERT INTO federation_requests 
                (from_instance_url, from_community_name, to_community_id, request_message)
            VALUES ($1, $2, $3, $4)
            RETURNING id"#,
            from_instance_url,
            from_community_name,
            to_community_id,
            message
        )
        .fetch_one(pool)
        .await?;

        Ok(request_id)
    }

    /// Update instance trust level
    pub async fn set_trust_level(
        pool: &PgPool,
        instance_id: Uuid,
        trust_level: i32,
    ) -> Result<(), PluginError> {
        sqlx::query!(
            "UPDATE federated_instances SET trust_level = $2, updated_at = NOW() WHERE id = $1",
            instance_id,
            trust_level.clamp(1, 5)
        )
        .execute(pool)
        .await?;

        Ok(())
    }
}