use qdrant_client::Qdrant;
use qdrant_client::qdrant::{
    Condition, CreateCollectionBuilder, DeletePointsBuilder, Distance, FieldCondition, Filter,
    Match, PointStruct, SearchPointsBuilder, UpsertPointsBuilder, VectorParamsBuilder, Vectors,
    condition::ConditionOneOf, r#match::MatchValue, point_id::PointIdOptions, value,
};
use std::collections::HashMap;
use std::sync::Arc;

use super::client::{EmbedPayload, SearchResult};
use crate::embed::client::EmbedVector;

pub struct QdrantClient {
    inner: Arc<Qdrant>,
}

impl Clone for QdrantClient {
    fn clone(&self) -> Self {
        Self {
            inner: self.inner.clone(),
        }
    }
}

impl QdrantClient {
    pub async fn new(url: &str, api_key: Option<&str>) -> crate::Result<Self> {
        let mut builder = Qdrant::from_url(url);
        if let Some(key) = api_key {
            builder = builder.api_key(key);
        }
        let inner = builder
            .build()
            .map_err(|e| crate::AgentError::Qdrant(e.to_string()))?;
        Ok(Self {
            inner: Arc::new(inner),
        })
    }

    fn collection_name(entity_type: &str) -> String {
        format!("embed_{}", entity_type)
    }

    /// Generate the collection name for a room's memory vectors.
    pub fn room_memory_collection_name(project_name: &str, room_id: &str) -> String {
        let _ = project_name;
        format!("room_memory_{}", room_id.replace('-', "_"))
    }

    pub async fn ensure_collection(&self, entity_type: &str, dimensions: u64) -> crate::Result<()> {
        let name = Self::collection_name(entity_type);
        self.ensure_collection_named(&name, dimensions).await
    }

    async fn ensure_collection_named(&self, name: &str, dimensions: u64) -> crate::Result<()> {
        let exists = self
            .inner
            .collection_exists(name)
            .await
            .map_err(|e| crate::AgentError::Qdrant(e.to_string()))?;

        if exists {
            return Ok(());
        }

        let create_collection = CreateCollectionBuilder::new(name)
            .vectors_config(VectorParamsBuilder::new(dimensions, Distance::Cosine))
            .build();

        self.inner
            .create_collection(create_collection)
            .await
            .map_err(|e| crate::AgentError::Qdrant(e.to_string()))?;

        Ok(())
    }

    /// Ensure a room-specific memory collection exists.
    pub async fn ensure_room_memory_collection(
        &self,
        project_name: &str,
        room_id: &str,
        dimensions: u64,
    ) -> crate::Result<()> {
        let name = Self::room_memory_collection_name(project_name, room_id);
        self.ensure_collection_named(&name, dimensions).await
    }

    pub async fn upsert_points(&self, points: Vec<EmbedVector>) -> crate::Result<()> {
        if points.is_empty() {
            return Ok(());
        }

        // Reject empty vectors — they cause Qdrant to reject the entire batch
        let empty_vectors = points.iter().filter(|p| p.vector.is_empty()).count();
        if empty_vectors > 0 {
            tracing::error!(
                empty_count = empty_vectors,
                total = points.len(),
                "upsert_points: REJECTING points with empty vectors"
            );
            return Err(crate::AgentError::Qdrant(format!(
                "refusing to upsert {} points with empty vectors",
                empty_vectors
            )));
        }

        let collection_name = Self::collection_name(&points[0].payload.entity_type);
        self.upsert_to_collection(&collection_name, points).await
    }

    /// Upsert points into a specific collection by name.
    pub async fn upsert_to_collection(
        &self,
        collection_name: &str,
        points: Vec<EmbedVector>,
    ) -> crate::Result<()> {
        if points.is_empty() {
            return Ok(());
        }

        let qdrant_points: Vec<PointStruct> = points
            .into_iter()
            .map(|p| {
                let mut payload: HashMap<String, qdrant_client::qdrant::Value> = HashMap::new();
                payload.insert("entity_type".to_string(), p.payload.entity_type.into());
                payload.insert("entity_id".to_string(), p.payload.entity_id.into());
                payload.insert("text".to_string(), p.payload.text.into());
                if let Some(extra) = p.payload.extra {
                    let extra_str = serde_json::to_string(&extra).unwrap_or_default();
                    payload.insert(
                        "extra".to_string(),
                        qdrant_client::qdrant::Value {
                            kind: Some(qdrant_client::qdrant::value::Kind::StringValue(extra_str)),
                        },
                    );
                }

                PointStruct::new(p.id, Vectors::from(p.vector), payload)
            })
            .collect();

        let upsert = UpsertPointsBuilder::new(collection_name, qdrant_points).build();

        self.inner
            .upsert_points(upsert)
            .await
            .map_err(|e| crate::AgentError::Qdrant(e.to_string()))?;

        Ok(())
    }

    fn extract_string(value: &qdrant_client::qdrant::Value) -> String {
        match &value.kind {
            Some(value::Kind::StringValue(s)) => s.clone(),
            _ => String::new(),
        }
    }

    pub async fn search(
        &self,
        vector: &[f32],
        entity_type: &str,
        limit: usize,
    ) -> crate::Result<Vec<SearchResult>> {
        let collection_name = Self::collection_name(entity_type);
        self.search_collection(&collection_name, vector, limit)
            .await
    }

    /// Search a specific collection by name.
    pub async fn search_collection(
        &self,
        collection_name: &str,
        vector: &[f32],
        limit: usize,
    ) -> crate::Result<Vec<SearchResult>> {
        let search_req = SearchPointsBuilder::new(collection_name, vector.to_vec(), limit as u64)
            .with_payload(true)
            .build();

        let results = self
            .inner
            .search_points(search_req)
            .await
            .map_err(|e| crate::AgentError::Qdrant(e.to_string()))?;

        Ok(results
            .result
            .into_iter()
            .filter_map(|p| {
                let entity_type = p
                    .payload
                    .get(&"entity_type".to_string())
                    .map(Self::extract_string)
                    .unwrap_or_default();

                let entity_id = p
                    .payload
                    .get(&"entity_id".to_string())
                    .map(Self::extract_string)
                    .unwrap_or_default();

                let text = p
                    .payload
                    .get(&"text".to_string())
                    .map(Self::extract_string)
                    .unwrap_or_default();

                let extra = p.payload.get(&"extra".to_string()).and_then(|v| {
                    let s = Self::extract_string(v);
                    if s.is_empty() {
                        None
                    } else {
                        serde_json::from_str::<serde_json::Value>(&s).ok()
                    }
                });

                let id =
                    p.id.and_then(|id| id.point_id_options)
                        .map(|opts| match opts {
                            PointIdOptions::Uuid(s) => s,
                            PointIdOptions::Num(n) => n.to_string(),
                        })
                        .unwrap_or_default();

                Some(SearchResult {
                    id,
                    score: p.score,
                    payload: EmbedPayload {
                        entity_type,
                        entity_id,
                        text,
                        extra,
                    },
                })
            })
            .collect())
    }

    pub async fn search_with_filter(
        &self,
        vector: &[f32],
        entity_type: &str,
        limit: usize,
        filter: Filter,
    ) -> crate::Result<Vec<SearchResult>> {
        let collection_name = Self::collection_name(entity_type);

        let search = SearchPointsBuilder::new(collection_name, vector.to_vec(), limit as u64)
            .with_payload(true)
            .filter(filter)
            .build();

        let results = self
            .inner
            .search_points(search)
            .await
            .map_err(|e| crate::AgentError::Qdrant(e.to_string()))?;

        Ok(results
            .result
            .into_iter()
            .filter_map(|p| {
                let entity_type = p
                    .payload
                    .get(&"entity_type".to_string())
                    .map(Self::extract_string)
                    .unwrap_or_default();

                let entity_id = p
                    .payload
                    .get(&"entity_id".to_string())
                    .map(Self::extract_string)
                    .unwrap_or_default();

                let text = p
                    .payload
                    .get(&"text".to_string())
                    .map(Self::extract_string)
                    .unwrap_or_default();

                let extra = p.payload.get(&"extra".to_string()).and_then(|v| {
                    let s = Self::extract_string(v);
                    if s.is_empty() {
                        None
                    } else {
                        serde_json::from_str::<serde_json::Value>(&s).ok()
                    }
                });

                let id =
                    p.id.and_then(|id| id.point_id_options)
                        .map(|opts| match opts {
                            PointIdOptions::Uuid(s) => s,
                            PointIdOptions::Num(n) => n.to_string(),
                        })
                        .unwrap_or_default();

                Some(SearchResult {
                    id,
                    score: p.score,
                    payload: EmbedPayload {
                        entity_type,
                        entity_id,
                        text,
                        extra,
                    },
                })
            })
            .collect())
    }

    pub async fn delete_by_filter(&self, entity_type: &str, entity_id: &str) -> crate::Result<()> {
        let collection_name = Self::collection_name(entity_type);

        let filter = Filter {
            must: vec![Condition {
                condition_one_of: Some(ConditionOneOf::Field(FieldCondition {
                    key: "entity_id".to_string(),
                    r#match: Some(Match {
                        match_value: Some(MatchValue::Keyword(entity_id.to_string())),
                    }),
                    ..Default::default()
                })),
            }],
            ..Default::default()
        };

        let delete = DeletePointsBuilder::new(collection_name)
            .points(filter)
            .build();

        self.inner
            .delete_points(delete)
            .await
            .map_err(|e| crate::AgentError::Qdrant(e.to_string()))?;

        Ok(())
    }

    pub async fn delete_collection(&self, entity_type: &str) -> crate::Result<()> {
        let name = Self::collection_name(entity_type);
        self.inner
            .delete_collection(name)
            .await
            .map_err(|e| crate::AgentError::Qdrant(e.to_string()))?;
        Ok(())
    }

    pub async fn ensure_memory_collection(&self, dimensions: u64) -> crate::Result<()> {
        self.ensure_collection("memory", dimensions).await
    }

    pub async fn ensure_skill_collection(&self, dimensions: u64) -> crate::Result<()> {
        self.ensure_collection("skill", dimensions).await
    }

    pub async fn search_memory(
        &self,
        vector: &[f32],
        limit: usize,
    ) -> crate::Result<Vec<SearchResult>> {
        self.search(vector, "memory", limit).await
    }

    pub async fn search_skill(
        &self,
        vector: &[f32],
        limit: usize,
    ) -> crate::Result<Vec<SearchResult>> {
        self.search(vector, "skill", limit).await
    }
}