// src/tables_data/handlers/post_table_data.rs

use tonic::Status;
use sqlx::{PgPool, Arguments};
use sqlx::postgres::PgArguments;
use chrono::{DateTime, Utc};
use common::proto::multieko2::tables_data::{PostTableDataRequest, PostTableDataResponse};
use std::collections::HashMap;
use std::sync::Arc;
use prost_types::value::Kind;

use crate::steel::server::execution::{self, Value};
use crate::steel::server::functions::SteelContext;

use crate::indexer::{IndexCommand, IndexCommandData};
use tokio::sync::mpsc;
use tracing::error;

pub async fn post_table_data(
    db_pool: &PgPool,
    request: PostTableDataRequest,
    indexer_tx: &mpsc::Sender<IndexCommand>,
) -> Result<PostTableDataResponse, Status> {
    let profile_name = request.profile_name;
    let table_name = request.table_name;

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

    let schema_id = schema.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 schema_id = $1 AND table_name = $2"#,
        schema_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
    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)))?;

    // Build system columns with foreign keys
    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));
    }

    // Convert to HashSet for faster lookups
    let system_columns_set: std::collections::HashSet<_> = system_columns.iter().map(|s| s.as_str()).collect();

    // Validate all data columns
    let user_columns: Vec<&String> = columns.iter().map(|(name, _)| name).collect();
    for key in request.data.keys() {
        if !system_columns_set.contains(key.as_str()) &&
           !user_columns.contains(&&key.to_string()) {
            return Err(Status::invalid_argument(format!("Invalid column: {}", key)));
        }
    }

    // ========================================================================
    // FIX #1: SCRIPT VALIDATION LOOP
    // This loop now correctly handles JSON `null` (which becomes `None`).
    // ========================================================================
    let mut string_data_for_scripts = HashMap::new();
    for (key, proto_value) in &request.data {
        let str_val = match &proto_value.kind {
            Some(Kind::StringValue(s)) => s.clone(),
            Some(Kind::NumberValue(n)) => n.to_string(),
            Some(Kind::BoolValue(b)) => b.to_string(),
            // This now correctly skips both protobuf `NULL` and JSON `null`.
            Some(Kind::NullValue(_)) | None => continue,
            Some(Kind::StructValue(_)) | Some(Kind::ListValue(_)) => {
                return Err(Status::invalid_argument(format!("Unsupported type for script validation in column '{}'", key)));
            }
        };
        string_data_for_scripts.insert(key.clone(), str_val);
    }

    // Validate Steel scripts
    let scripts = sqlx::query!(
        "SELECT target_column, script FROM table_scripts WHERE table_definitions_id = $1",
        table_def.id
    )
    .fetch_all(db_pool)
    .await
    .map_err(|e| Status::internal(format!("Failed to fetch scripts: {}", e)))?;

    for script_record in scripts {
        let target_column = script_record.target_column;

        let user_value = string_data_for_scripts.get(&target_column)
            .ok_or_else(|| Status::invalid_argument(
                format!("Script target column '{}' is required", target_column)
            ))?;

        let context = SteelContext {
            current_table: table_name.clone(),
            schema_id,
            schema_name: profile_name.clone(),
            row_data: string_data_for_scripts.clone(),
            db_pool: Arc::new(db_pool.clone()),
        };

        let script_result = execution::execute_script(
            script_record.script,
            "STRINGS",
            Arc::new(db_pool.clone()),
            context,
        )
        .map_err(|e| Status::invalid_argument(
            format!("Script execution failed for '{}': {}", target_column, e)
        ))?;

        let Value::Strings(mut script_output) = script_result else {
            return Err(Status::internal("Script must return string values"));
        };

        let expected_value = script_output.pop()
            .ok_or_else(|| Status::internal("Script returned no values"))?;

        if user_value != &expected_value {
            return Err(Status::invalid_argument(format!(
                "Validation failed for column '{}': Expected '{}', Got '{}'",
                target_column, expected_value, user_value
            )));
        }
    }

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

    // ========================================================================
    // FIX #2: DATABASE INSERTION LOOP
    // This loop now correctly handles JSON `null` (which becomes `None`)
    // without crashing and correctly inserts a SQL NULL.
    // ========================================================================
    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)))?
        };

        // Check for `None` (from JSON null) or `Some(NullValue)` first.
        let kind = match &proto_value.kind {
            None | Some(Kind::NullValue(_)) => {
                // It's a null value. Add the correct SQL NULL type and continue.
                match sql_type {
                    "BOOLEAN" => params.add(None::<bool>),
                    "TEXT" | "VARCHAR(15)" | "VARCHAR(255)" => params.add(None::<String>),
                    "TIMESTAMPTZ" => params.add(None::<DateTime<Utc>>),
                    "BIGINT" => params.add(None::<i64>),
                    _ => return Err(Status::invalid_argument(format!("Unsupported type for null value: {}", sql_type))),
                }.map_err(|e| Status::internal(format!("Failed to add null parameter for {}: {}", col, e)))?;

                columns_list.push(format!("\"{}\"", col));
                placeholders.push(format!("${}", param_idx));
                param_idx += 1;
                continue; // Skip to the next column in the loop
            }
            // If it's not null, just pass the inner `Kind` through.
            Some(k) => k,
        };

        // From here, we know `kind` is not a null type.
        match sql_type {
            "TEXT" | "VARCHAR(15)" | "VARCHAR(255)" => {
                if let Kind::StringValue(value) = kind {
                    if let Some(max_len) = sql_type.strip_prefix("VARCHAR(").and_then(|s| s.strip_suffix(')')).and_then(|s| s.parse::<usize>().ok()) {
                        if value.len() > max_len {
                            return Err(Status::internal(format!("Value too long for {}", col)));
                        }
                    }
                    params.add(value).map_err(|e| Status::invalid_argument(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::invalid_argument(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::invalid_argument(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::invalid_argument(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))),
        }

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

    if columns_list.is_empty() {
        return Err(Status::invalid_argument("No valid columns to insert"));
    }

    // Qualify table name with schema
    let qualified_table = crate::shared::schema_qualifier::qualify_table_name_for_data(
        db_pool,
        &profile_name,
        &table_name,
    )
    .await?;

    let sql = format!(
        "INSERT INTO {} ({}) VALUES ({}) RETURNING id",
        qualified_table,
        columns_list.join(", "),
        placeholders.join(", ")
    );

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

    let inserted_id = match result {
        Ok(id) => id,
        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
                    )));
                }
            }
            return Err(Status::internal(format!("Insert failed: {}", e)));
        }
    };

    let command = IndexCommand::AddOrUpdate(IndexCommandData {
        table_name: table_name.clone(),
        row_id: inserted_id,
    });

    if let Err(e) = indexer_tx.send(command).await {
        error!(
            "CRITICAL: DB insert for table '{}' (id: {}) succeeded but failed to queue for indexing: {}. Search index is now inconsistent.",
            table_name, inserted_id, e
        );
    }

    Ok(PostTableDataResponse {
        success: true,
        message: "Data inserted successfully".into(),
        inserted_id,
    })
}