// src/tables_data/handlers/put_table_data.rs
use tonic::Status;
use sqlx::{PgPool, Arguments, Postgres};
use sqlx::postgres::PgArguments;
use chrono::{DateTime, Utc};
use common::proto::multieko2::tables_data::{PutTableDataRequest, PutTableDataResponse};
use crate::shared::schema_qualifier::qualify_table_name_for_data;
use prost_types::value::Kind;

pub async fn put_table_data(
    db_pool: &PgPool,
    request: PutTableDataRequest,
) -> Result<PutTableDataResponse, Status> {
    let profile_name = request.profile_name;
    let table_name = request.table_name;
    let record_id = request.id;

    // If no data is provided to update, it's an invalid request.
    if request.data.is_empty() {
        return Err(Status::invalid_argument("No fields provided to update."));
    }

    // Lookup profile
    let profile = sqlx::query!(
        "SELECT id FROM profiles WHERE name = $1",
        profile_name
    )
    .fetch_optional(db_pool)
    .await
    .map_err(|e| Status::internal(format!("Profile lookup error: {}", e)))?;

    let profile_id = profile.ok_or_else(|| Status::not_found("Profile not found"))?.id;

    // Lookup table_definition
    let table_def = sqlx::query!(
        r#"SELECT id, columns FROM table_definitions
        WHERE profile_id = $1 AND table_name = $2"#,
        profile_id,
        table_name
    )
    .fetch_optional(db_pool)
    .await
    .map_err(|e| Status::internal(format!("Table lookup error: {}", e)))?;

    let table_def = table_def.ok_or_else(|| Status::not_found("Table not found"))?;

    // Parse columns from JSON
    let columns_json: Vec<String> = serde_json::from_value(table_def.columns.clone())
        .map_err(|e| Status::internal(format!("Column parsing error: {}", e)))?;

    let mut columns = Vec::new();
    for col_def in columns_json {
        let parts: Vec<&str> = col_def.splitn(2, ' ').collect();
        if parts.len() != 2 {
            return Err(Status::internal("Invalid column format"));
        }
        let name = parts[0].trim_matches('"').to_string();
        let sql_type = parts[1].to_string();
        columns.push((name, sql_type));
    }

    // Get all foreign key columns for this table (needed for validation)
    let fk_columns = sqlx::query!(
        r#"SELECT ltd.table_name
        FROM table_definition_links tdl
        JOIN table_definitions ltd ON tdl.linked_table_id = ltd.id
        WHERE tdl.source_table_id = $1"#,
        table_def.id
    )
    .fetch_all(db_pool)
    .await
    .map_err(|e| Status::internal(format!("Foreign key lookup error: {}", e)))?;

    let mut system_columns = vec!["deleted".to_string()];
    for fk in fk_columns {
        let base_name = fk.table_name.split_once('_').map_or(fk.table_name.as_str(), |(_, rest)| rest);
        system_columns.push(format!("{}_id", base_name));
    }
    let system_columns_set: std::collections::HashSet<_> = system_columns.iter().map(|s| s.as_str()).collect();
    let user_columns: Vec<&String> = columns.iter().map(|(name, _)| name).collect();

    // Validate input columns
    for key in request.data.keys() {
        if !system_columns_set.contains(key.as_str()) && !user_columns.contains(&key) {
            return Err(Status::invalid_argument(format!("Invalid column: {}", key)));
        }
    }

    // Prepare SQL parameters
    let mut params = PgArguments::default();
    let mut set_clauses = Vec::new();
    let mut param_idx = 1;

    for (col, proto_value) in request.data {
        let sql_type = if system_columns_set.contains(col.as_str()) {
            match col.as_str() {
                "deleted" => "BOOLEAN",
                _ if col.ends_with("_id") => "BIGINT",
                _ => return Err(Status::invalid_argument("Invalid system column")),
            }
        } else {
            columns.iter()
                .find(|(name, _)| name == &col)
                .map(|(_, sql_type)| sql_type.as_str())
                .ok_or_else(|| Status::invalid_argument(format!("Column not found: {}", col)))?
        };

        // A provided value cannot be null or empty in a PUT request.
        // To clear a field, it should be set to an empty string "" for text,
        // or a specific value for other types if needed (though typically not done).
        // For now, we reject nulls.
        let kind = proto_value.kind.ok_or_else(|| {
            Status::invalid_argument(format!("Value for column '{}' cannot be empty in a PUT request. To clear a text field, send an empty string.", col))
        })?;

        match sql_type {
            "TEXT" | "VARCHAR(15)" | "VARCHAR(255)" => {
                if let Kind::StringValue(value) = kind {
                    params.add(value)
                        .map_err(|e| Status::internal(format!("Failed to add text parameter for {}: {}", col, e)))?;
                } else {
                    return Err(Status::invalid_argument(format!("Expected string for column '{}'", col)));
                }
            },
            "BOOLEAN" => {
                if let Kind::BoolValue(val) = kind {
                    params.add(val)
                        .map_err(|e| Status::internal(format!("Failed to add boolean parameter for {}: {}", col, e)))?;
                } else {
                    return Err(Status::invalid_argument(format!("Expected boolean for column '{}'", col)));
                }
            },
            "TIMESTAMPTZ" => {
                if let Kind::StringValue(value) = kind {
                    let dt = DateTime::parse_from_rfc3339(&value)
                        .map_err(|_| Status::invalid_argument(format!("Invalid timestamp for {}", col)))?;
                    params.add(dt.with_timezone(&Utc))
                        .map_err(|e| Status::internal(format!("Failed to add timestamp parameter for {}: {}", col, e)))?;
                } else {
                    return Err(Status::invalid_argument(format!("Expected ISO 8601 string for column '{}'", col)));
                }
            },
            "BIGINT" => {
                if let Kind::NumberValue(val) = kind {
                    if val.fract() != 0.0 {
                        return Err(Status::invalid_argument(format!("Expected integer for column '{}', but got a float", col)));
                    }
                    params.add(val as i64)
                        .map_err(|e| Status::internal(format!("Failed to add integer parameter for {}: {}", col, e)))?;
                } else {
                    return Err(Status::invalid_argument(format!("Expected number for column '{}'", col)));
                }
            },
            _ => return Err(Status::invalid_argument(format!("Unsupported type {}", sql_type))),
        }

        set_clauses.push(format!("\"{}\" = ${}", col, param_idx));
        param_idx += 1;
    }

    params.add(record_id)
        .map_err(|e| Status::internal(format!("Failed to add record_id parameter: {}", e)))?;

    let qualified_table = qualify_table_name_for_data(
        db_pool,
        &profile_name,
        &table_name,
    )
    .await?;
    let set_clause = set_clauses.join(", ");
    let sql = format!(
        "UPDATE {} SET {} WHERE id = ${} AND deleted = FALSE RETURNING id",
        qualified_table,
        set_clause,
        param_idx
    );

    let result = sqlx::query_scalar_with::<Postgres, i64, _>(&sql, params)
        .fetch_optional(db_pool)
        .await;

    match result {
        Ok(Some(updated_id)) => Ok(PutTableDataResponse {
            success: true,
            message: "Data updated successfully".into(),
            updated_id,
        }),
        Ok(None) => Err(Status::not_found("Record not found or already deleted")),
        Err(e) => {
            if let Some(db_err) = e.as_database_error() {
                if db_err.code() == Some(std::borrow::Cow::Borrowed("42P01")) {
                    return Err(Status::internal(format!(
                        "Table '{}' is defined but does not physically exist in the database as {}",
                        table_name, qualified_table
                    )));
                }
            }
            Err(Status::internal(format!("Update failed: {}", e)))
        }
    }
}