//! Record CRUD operations and queries.
//!
//! This module handles all database operations related to ATProto records,
//! including insertion, updates, deletion, and complex queries with filtering,
//! sorting, and pagination.

use super::client::Database;
use super::cursor::{build_cursor_where_condition, decode_cursor, generate_cursor_from_record};
use super::query_builder::{bind_where_parameters, build_order_by_clause_with_field_info, build_where_conditions};
use super::types::{SortField, WhereClause};
use crate::errors::DatabaseError;
use crate::models::{IndexedRecord, Record};

impl Database {
    /// Inserts a single record into the database.
    ///
    /// Uses ON CONFLICT to update existing records with matching URI and slice_uri.
    pub async fn insert_record(&self, record: &Record) -> Result<(), DatabaseError> {
        sqlx::query!(
            r#"INSERT INTO "record" ("uri", "cid", "did", "collection", "json", "indexed_at", "slice_uri")
               VALUES ($1, $2, $3, $4, $5, $6, $7)
               ON CONFLICT ON CONSTRAINT record_pkey
               DO UPDATE SET
                   "cid" = EXCLUDED."cid",
                   "json" = EXCLUDED."json",
                   "indexed_at" = EXCLUDED."indexed_at""#,
            record.uri,
            record.cid,
            record.did,
            record.collection,
            record.json,
            record.indexed_at,
            record.slice_uri
        )
        .execute(&self.pool)
        .await?;

        Ok(())
    }

    /// Inserts multiple records in optimized batches.
    ///
    /// Automatically chunks records to stay within PostgreSQL parameter limits
    /// (65536 parameters, ~8000 records per batch with 7 fields each).
    pub async fn batch_insert_records(&self, records: &[Record]) -> Result<(), DatabaseError> {
        if records.is_empty() {
            return Ok(());
        }

        const BATCH_SIZE: usize = 8000;

        for chunk in records.chunks(BATCH_SIZE) {
            self.batch_insert_records_chunk(chunk).await?;
        }

        Ok(())
    }

    /// Internal helper to insert a single chunk of records.
    async fn batch_insert_records_chunk(&self, records: &[Record]) -> Result<(), DatabaseError> {
        let mut tx = self.pool.begin().await?;

        let mut deduped = std::collections::HashMap::new();
        for record in records {
            let key = (&record.uri, &record.slice_uri);
            deduped.insert(key, record);
        }
        let records: Vec<&Record> = deduped.into_values().collect();

        let mut query = String::from(
            r#"INSERT INTO "record" ("uri", "cid", "did", "collection", "json", "indexed_at", "slice_uri") VALUES "#,
        );

        for (i, _) in records.iter().enumerate() {
            if i > 0 {
                query.push_str(", ");
            }
            let base = i * 7 + 1;
            query.push_str(&format!(
                "(${}, ${}, ${}, ${}, ${}, ${}, ${})",
                base,
                base + 1,
                base + 2,
                base + 3,
                base + 4,
                base + 5,
                base + 6
            ));
        }

        query.push_str(
            r#"
            ON CONFLICT ON CONSTRAINT record_pkey
            DO UPDATE SET
                "cid" = EXCLUDED."cid",
                "json" = EXCLUDED."json",
                "indexed_at" = EXCLUDED."indexed_at"
        "#,
        );

        let mut sqlx_query = sqlx::query(&query);
        for record in records {
            sqlx_query = sqlx_query
                .bind(&record.uri)
                .bind(&record.cid)
                .bind(&record.did)
                .bind(&record.collection)
                .bind(&record.json)
                .bind(record.indexed_at)
                .bind(&record.slice_uri);
        }

        sqlx_query.execute(&mut *tx).await?;
        tx.commit().await?;

        Ok(())
    }

    /// Gets a map of existing record CIDs for a specific actor, collection, and slice.
    ///
    /// Used during sync to determine which records need updating vs inserting.
    ///
    /// # Returns
    /// HashMap mapping URI -> CID
    pub async fn get_existing_record_cids_for_slice(
        &self,
        did: &str,
        collection: &str,
        slice_uri: &str,
    ) -> Result<std::collections::HashMap<String, String>, DatabaseError> {
        let records = sqlx::query!(
            r#"SELECT "uri", "cid"
               FROM "record"
               WHERE "did" = $1 AND "collection" = $2 AND "slice_uri" = $3"#,
            did,
            collection,
            slice_uri
        )
        .fetch_all(&self.pool)
        .await?;

        let mut cid_map = std::collections::HashMap::new();
        for record in records {
            cid_map.insert(record.uri, record.cid);
        }
        Ok(cid_map)
    }

    /// Retrieves a single record by URI.
    ///
    /// # Returns
    /// Some(IndexedRecord) if found, None otherwise
    pub async fn get_record(&self, uri: &str) -> Result<Option<IndexedRecord>, DatabaseError> {
        let record = sqlx::query_as::<_, Record>(
            r#"SELECT "uri", "cid", "did", "collection", "json", "indexed_at", "slice_uri"
               FROM "record"
               WHERE "uri" = $1"#,
        )
        .bind(uri)
        .fetch_optional(&self.pool)
        .await?;

        let indexed_record = record.map(|record| IndexedRecord {
            uri: record.uri,
            cid: record.cid,
            did: record.did,
            collection: record.collection,
            value: record.json,
            indexed_at: record.indexed_at.to_rfc3339(),
        });

        Ok(indexed_record)
    }

    /// Updates an existing record.
    ///
    /// Returns error if no record with matching URI and slice_uri exists.
    pub async fn update_record(&self, record: &Record) -> Result<(), DatabaseError> {
        let result = sqlx::query!(
            r#"UPDATE "record"
               SET "cid" = $1, "json" = $2, "indexed_at" = $3
               WHERE "uri" = $4 AND "slice_uri" = $5"#,
            record.cid,
            record.json,
            record.indexed_at,
            record.uri,
            record.slice_uri
        )
        .execute(&self.pool)
        .await?;

        if result.rows_affected() == 0 {
            return Err(DatabaseError::RecordNotFound {
                uri: record.uri.clone(),
            });
        }

        Ok(())
    }

    /// Queries records for a slice with advanced filtering, sorting, and pagination.
    ///
    /// Supports:
    /// - Cursor-based pagination
    /// - Multi-field sorting (with JSON path support)
    /// - Complex WHERE conditions (AND/OR, eq/in/contains operators)
    /// - Automatic handling of lexicon records vs regular records
    ///
    /// # Returns
    /// Tuple of (records, next_cursor)
    pub async fn get_slice_collections_records(
        &self,
        slice_uri: &str,
        limit: Option<i32>,
        cursor: Option<&str>,
        sort_by: Option<&Vec<SortField>>,
        where_clause: Option<&WhereClause>,
    ) -> Result<(Vec<Record>, Option<String>), DatabaseError> {
        let limit = limit.unwrap_or(50).min(100);

        let mut where_clauses = Vec::new();
        let mut param_count = 1;

        // Extract collection name from where clause for lexicon lookup
        let collection = where_clause
            .as_ref()
            .and_then(|wc| wc.conditions.get("collection"))
            .and_then(|c| c.eq.as_ref())
            .and_then(|v| v.as_str());

        // Determine which sort fields are datetime fields by checking lexicons
        let field_types: Option<Vec<bool>> = if let Some(collection_name) = collection {
            if let Some(sort_fields) = sort_by {
                // Fetch lexicons to check field types for ALL sort fields
                match self.get_lexicons_by_slice(slice_uri).await {
                    Ok(lexicons) => {
                        let types: Vec<bool> = sort_fields
                            .iter()
                            .map(|field| is_field_datetime(&lexicons, collection_name, &field.field))
                            .collect();
                        Some(types)
                    }
                    Err(_) => None,
                }
            } else {
                None
            }
        } else {
            None
        };

        // Get first field type for ORDER BY (for backward compatibility)
        let primary_field_is_datetime = field_types.as_ref().and_then(|types| types.first().copied());

        // Build ORDER BY clause with datetime field information
        let order_by = build_order_by_clause_with_field_info(sort_by, primary_field_is_datetime);

        let is_lexicon = where_clause
            .as_ref()
            .and_then(|wc| wc.conditions.get("collection"))
            .and_then(|c| c.eq.as_ref())
            .and_then(|v| v.as_str())
            == Some("network.slices.lexicon");

        if is_lexicon {
            where_clauses.push(format!("json->>'slice' = ${}", param_count));
        } else {
            where_clauses.push(format!("slice_uri = ${}", param_count));
        }
        param_count += 1;

        // Build all other WHERE conditions first (including collection filter)
        // For non-lexicon records, exclude the 'slice' field since we handle it via slice_uri
        let mut filtered_where_clause = None;
        let filtered_clause;

        if is_lexicon {
            filtered_where_clause = where_clause;
        } else if let Some(wc) = where_clause {
            let mut filtered_conditions = std::collections::HashMap::new();
            for (field, condition) in &wc.conditions {
                if field != "slice" {
                    filtered_conditions.insert(field.clone(), condition.clone());
                }
            }

            filtered_clause = WhereClause {
                conditions: filtered_conditions,
                or_conditions: wc.or_conditions.clone(),
            };
            filtered_where_clause = Some(&filtered_clause);
        }

        let (and_conditions, or_conditions) =
            build_where_conditions(filtered_where_clause, &mut param_count);
        where_clauses.extend(and_conditions);

        // Add cursor conditions last to ensure proper parameter order
        let mut cursor_bind_values = Vec::new();
        if let Some(cursor_str) = cursor {
            match decode_cursor(cursor_str, sort_by) {
                Ok(decoded_cursor) => {
                    // Use the datetime field information we already computed
                    let field_type_slice = field_types.as_deref();
                    let (cursor_where, bind_values) =
                        build_cursor_where_condition(&decoded_cursor, sort_by, &mut param_count, field_type_slice);
                    where_clauses.push(cursor_where);
                    cursor_bind_values = bind_values;
                }
                Err(e) => {
                    // Log the error but don't fail the request
                    eprintln!("Invalid cursor format: {}", e);
                }
            }
        }

        if !or_conditions.is_empty() {
            let or_clause = format!("({})", or_conditions.join(" OR "));
            where_clauses.push(or_clause);
        }

        let where_sql = where_clauses.into_iter().filter(|clause| !clause.is_empty()).collect::<Vec<_>>().join(" AND ");

        // Assign limit parameter AFTER all other parameters
        let limit_param = param_count;

        let query = format!(
            "SELECT uri, cid, did, collection, json, indexed_at, slice_uri
             FROM record
             WHERE {}
             ORDER BY {}
             LIMIT ${}",
            where_sql, order_by, limit_param
        );

        let mut query_builder = sqlx::query_as::<_, Record>(&query);

        query_builder = query_builder.bind(slice_uri);

        // Bind WHERE condition parameters (including collection filter)
        query_builder = bind_where_parameters(query_builder, filtered_where_clause);

        // Bind cursor values after WHERE conditions
        for cursor_value in cursor_bind_values {
            query_builder = query_builder.bind(cursor_value);
        }

        query_builder = query_builder.bind(limit as i64);

        let records = query_builder.fetch_all(&self.pool).await?;

        // Only return cursor if we got a full page, indicating there might be more
        let cursor = if records.len() < limit as usize {
            None  // Last page - no more results
        } else {
            records
                .last()
                .map(|record| generate_cursor_from_record(record, sort_by))
        };

        Ok((records, cursor))
    }

    /// Counts records matching the given criteria.
    ///
    /// Used for pagination metadata and statistics.
    pub async fn count_slice_collections_records(
        &self,
        slice_uri: &str,
        where_clause: Option<&WhereClause>,
    ) -> Result<i64, DatabaseError> {
        let mut where_clauses = Vec::new();
        let mut param_count = 1;

        let is_lexicon = where_clause
            .as_ref()
            .and_then(|wc| wc.conditions.get("collection"))
            .and_then(|c| c.eq.as_ref())
            .and_then(|v| v.as_str())
            == Some("network.slices.lexicon");

        if is_lexicon {
            where_clauses.push(format!("json->>'slice' = ${}", param_count));
        } else {
            where_clauses.push(format!("slice_uri = ${}", param_count));
        }
        param_count += 1;

        let (and_conditions, or_conditions) =
            build_where_conditions(where_clause, &mut param_count);
        where_clauses.extend(and_conditions);

        if !or_conditions.is_empty() {
            let or_clause = format!("({})", or_conditions.join(" OR "));
            where_clauses.push(or_clause);
        }

        let filtered_where_clauses: Vec<_> = where_clauses.into_iter().filter(|clause| !clause.is_empty()).collect();
        let where_sql = if filtered_where_clauses.is_empty() {
            String::new()
        } else {
            format!(" WHERE {}", filtered_where_clauses.join(" AND "))
        };

        let query = format!("SELECT COUNT(*) as count FROM record{}", where_sql);

        let mut query_builder = sqlx::query_scalar::<_, i64>(&query);
        query_builder = query_builder.bind(slice_uri);

        if let Some(clause) = where_clause {
            for condition in clause.conditions.values() {
                if let Some(eq_value) = &condition.eq {
                    if let Some(str_val) = eq_value.as_str() {
                        query_builder = query_builder.bind(str_val);
                    } else {
                        query_builder = query_builder.bind(eq_value);
                    }
                }
                if let Some(in_values) = &condition.in_values {
                    let str_values: Vec<String> = in_values
                        .iter()
                        .filter_map(|v| v.as_str().map(|s| s.to_string()))
                        .collect();
                    query_builder = query_builder.bind(str_values);
                }
                if let Some(contains_value) = &condition.contains {
                    query_builder = query_builder.bind(contains_value);
                }
            }

            if let Some(or_conditions) = &clause.or_conditions {
                for condition in or_conditions.values() {
                    if let Some(eq_value) = &condition.eq {
                        if let Some(str_val) = eq_value.as_str() {
                            query_builder = query_builder.bind(str_val);
                        } else {
                            query_builder = query_builder.bind(eq_value);
                        }
                    }
                    if let Some(in_values) = &condition.in_values {
                        let str_values: Vec<String> = in_values
                            .iter()
                            .filter_map(|v| v.as_str().map(|s| s.to_string()))
                            .collect();
                        query_builder = query_builder.bind(str_values);
                    }
                    if let Some(contains_value) = &condition.contains {
                        query_builder = query_builder.bind(contains_value);
                    }
                }
            }
        }

        let count = query_builder.fetch_one(&self.pool).await?;
        Ok(count)
    }

    /// Deletes a record by URI.
    ///
    /// If slice_uri is provided, only deletes from that slice.
    /// Otherwise deletes from all slices.
    ///
    /// # Returns
    /// Number of rows affected
    pub async fn delete_record_by_uri(
        &self,
        uri: &str,
        slice_uri: Option<&str>,
    ) -> Result<u64, DatabaseError> {
        let result = if let Some(slice_uri) = slice_uri {
            sqlx::query("DELETE FROM record WHERE uri = $1 AND slice_uri = $2")
                .bind(uri)
                .bind(slice_uri)
                .execute(&self.pool)
                .await?
        } else {
            sqlx::query("DELETE FROM record WHERE uri = $1")
                .bind(uri)
                .execute(&self.pool)
                .await?
        };
        Ok(result.rows_affected())
    }

    /// Deletes all records for a specific slice.
    ///
    /// This is a destructive operation that removes all indexed records
    /// from the specified slice. Records can be recovered by re-syncing.
    ///
    /// # Arguments
    /// * `slice_uri` - AT-URI of the slice to clear
    ///
    /// # Returns
    /// Number of records deleted
    pub async fn delete_all_records_for_slice(
        &self,
        slice_uri: &str,
    ) -> Result<u64, DatabaseError> {
        let result = sqlx::query("DELETE FROM record WHERE slice_uri = $1 AND collection NOT LIKE 'network.slices.%'")
            .bind(slice_uri)
            .execute(&self.pool)
            .await?;
        Ok(result.rows_affected())
    }

    /// Deletes all records of a specific collection from a slice.
    ///
    /// Used when a lexicon is deleted to clean up all records of that type.
    ///
    /// # Arguments
    /// * `slice_uri` - AT-URI of the slice
    /// * `collection` - Collection name (NSID) to delete
    ///
    /// # Returns
    /// Number of records deleted
    pub async fn delete_records_by_collection(
        &self,
        slice_uri: &str,
        collection: &str,
    ) -> Result<u64, DatabaseError> {
        let result = sqlx::query("DELETE FROM record WHERE slice_uri = $1 AND collection = $2")
            .bind(slice_uri)
            .bind(collection)
            .execute(&self.pool)
            .await?;
        Ok(result.rows_affected())
    }

    /// Handles cascade deletion based on record type.
    ///
    /// When certain records are deleted, related data should be cleaned up:
    /// - Lexicon deletion: removes all records of that collection type
    /// - Slice deletion: removes all records and actors for that slice
    ///
    /// # Arguments
    /// * `uri` - AT-URI of the deleted record
    /// * `collection` - Collection name (e.g., "network.slices.lexicon")
    pub async fn handle_cascade_deletion(&self, uri: &str, collection: &str) -> Result<(), DatabaseError> {
        match collection {
            "network.slices.lexicon" => {
                // Get the lexicon record to extract collection name and slice URI
                if let Ok(Some(lexicon_record)) = self.get_record(uri).await
                    && let (Some(nsid), Some(slice_uri_from_record)) = (
                        lexicon_record.value.get("nsid").and_then(|v| v.as_str()),
                        lexicon_record.value.get("slice").and_then(|v| v.as_str())
                    )
                {
                    // Delete all records of this collection type from the slice
                    let deleted = self.delete_records_by_collection(slice_uri_from_record, nsid).await?;
                    tracing::info!(
                        "Cascade delete: removed {} records of collection {} from slice {}",
                        deleted, nsid, slice_uri_from_record
                    );
                }
            }
            "network.slices.slice" => {
                // The URI itself is the slice URI
                let slice_uri = uri;

                // Delete all records for this slice
                let records_deleted = self.delete_all_records_for_slice(slice_uri).await?;
                tracing::info!(
                    "Cascade delete: removed {} records from slice {}",
                    records_deleted, slice_uri
                );

                // Delete all actors for this slice
                let actors_deleted = super::client::Database::delete_all_actors_for_slice(self, slice_uri).await?;
                tracing::info!(
                    "Cascade delete: removed {} actors from slice {}",
                    actors_deleted, slice_uri
                );
            }
            _ => {
                // No cascade deletion needed for other collections
            }
        }
        Ok(())
    }

    /// Inserts or updates a record atomically.
    ///
    /// # Returns
    /// true if inserted (new record), false if updated (existing record)
    pub async fn upsert_record(&self, record: &Record) -> Result<bool, DatabaseError> {
        let result = sqlx::query_scalar::<_, bool>(
            r#"
            INSERT INTO record (uri, cid, did, collection, json, indexed_at, slice_uri)
            VALUES ($1, $2, $3, $4, $5, $6, $7)
            ON CONFLICT ON CONSTRAINT record_pkey DO UPDATE
            SET cid = EXCLUDED.cid,
                json = EXCLUDED.json,
                indexed_at = EXCLUDED.indexed_at
            RETURNING (xmax = 0)
        "#,
        )
        .bind(&record.uri)
        .bind(&record.cid)
        .bind(&record.did)
        .bind(&record.collection)
        .bind(&record.json)
        .bind(record.indexed_at)
        .bind(&record.slice_uri)
        .fetch_one(&self.pool)
        .await?;
        Ok(result)
    }

    /// Gets lexicon definitions for a specific slice.
    ///
    /// Filters for network.slices.lexicon records and transforms them
    /// into the lexicon JSON format expected by the lexicon parser.
    pub async fn get_lexicons_by_slice(
        &self,
        slice_uri: &str,
    ) -> Result<Vec<serde_json::Value>, DatabaseError> {
        let records = sqlx::query_as::<_, Record>(
            r#"SELECT "uri", "cid", "did", "collection", "json", "indexed_at", "slice_uri"
               FROM "record"
               WHERE "collection" = 'network.slices.lexicon'
               AND "json"->>'slice' = $1
               ORDER BY "indexed_at" DESC"#,
        )
        .bind(slice_uri)
        .fetch_all(&self.pool)
        .await?;

        let lexicon_definitions: Vec<serde_json::Value> = records
            .into_iter()
            .filter_map(|record| {
                let nsid = record.json.get("nsid")?.as_str()?;
                let definitions_str = record.json.get("definitions")?.as_str()?;
                let definitions: serde_json::Value = serde_json::from_str(definitions_str).ok()?;

                Some(serde_json::json!({
                    "lexicon": 1,
                    "id": nsid,
                    "defs": definitions
                }))
            })
            .collect();

        Ok(lexicon_definitions)
    }
}

/// Helper function to check if a field is a datetime field in the lexicon
fn is_field_datetime(lexicons: &[serde_json::Value], collection: &str, field: &str) -> bool {
    for lexicon in lexicons {
        if let Some(id) = lexicon.get("id").and_then(|v| v.as_str())
            && id == collection
            && let Some(defs) = lexicon.get("defs")
            && let Some(main) = defs.get("main")
            && let Some(record) = main.get("record")
            && let Some(properties) = record.get("properties")
            && let Some(field_def) = properties.get(field)
            && let Some(format) = field_def.get("format").and_then(|v| v.as_str())
        {
            return format == "datetime";
        }
    }
    false
}

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

    #[test]
    fn test_is_field_datetime_found() {
        let lexicons = vec![serde_json::json!({
            "lexicon": 1,
            "id": "app.bsky.feed.post",
            "defs": {
                "main": {
                    "record": {
                        "properties": {
                            "createdAt": {
                                "type": "string",
                                "format": "datetime"
                            },
                            "text": {
                                "type": "string"
                            }
                        }
                    }
                }
            }
        })];

        assert!(is_field_datetime(&lexicons, "app.bsky.feed.post", "createdAt"));
    }

    #[test]
    fn test_is_field_datetime_not_datetime() {
        let lexicons = vec![serde_json::json!({
            "lexicon": 1,
            "id": "app.bsky.feed.post",
            "defs": {
                "main": {
                    "record": {
                        "properties": {
                            "text": {
                                "type": "string"
                            }
                        }
                    }
                }
            }
        })];

        assert!(!is_field_datetime(&lexicons, "app.bsky.feed.post", "text"));
    }

    #[test]
    fn test_is_field_datetime_missing_field() {
        let lexicons = vec![serde_json::json!({
            "lexicon": 1,
            "id": "app.bsky.feed.post",
            "defs": {
                "main": {
                    "record": {
                        "properties": {
                            "text": {
                                "type": "string"
                            }
                        }
                    }
                }
            }
        })];

        assert!(!is_field_datetime(&lexicons, "app.bsky.feed.post", "nonexistent"));
    }

    #[test]
    fn test_is_field_datetime_wrong_collection() {
        let lexicons = vec![serde_json::json!({
            "lexicon": 1,
            "id": "app.bsky.feed.post",
            "defs": {
                "main": {
                    "record": {
                        "properties": {
                            "createdAt": {
                                "type": "string",
                                "format": "datetime"
                            }
                        }
                    }
                }
            }
        })];

        assert!(!is_field_datetime(&lexicons, "app.bsky.actor.profile", "createdAt"));
    }

    #[test]
    fn test_is_field_datetime_multiple_lexicons() {
        let lexicons = vec![
            serde_json::json!({
                "lexicon": 1,
                "id": "app.bsky.feed.post",
                "defs": {
                    "main": {
                        "record": {
                            "properties": {
                                "text": {
                                    "type": "string"
                                }
                            }
                        }
                    }
                }
            }),
            serde_json::json!({
                "lexicon": 1,
                "id": "app.bsky.actor.profile",
                "defs": {
                    "main": {
                        "record": {
                            "properties": {
                                "createdAt": {
                                    "type": "string",
                                    "format": "datetime"
                                }
                            }
                        }
                    }
                }
            }),
        ];

        assert!(is_field_datetime(&lexicons, "app.bsky.actor.profile", "createdAt"));
        assert!(!is_field_datetime(&lexicons, "app.bsky.feed.post", "text"));
    }
}