use crate::diff::diff_payload::DiffPayload;
use crate::diff::table::query::input::{
    QueryHashDataInput, QueryPrimaryKeysInput, QueryTableCountInput, QueryTableNamesInput,
};
use crate::diff::table::query::output::{TableCountDiff, TableDiffOutput, TableSource};

use crate::diff::table::query::table_query_executor::{
    TableDualSourceQueryExecutor, TableSingleSourceQueryExecutor,
};
use crate::diff::table::query::table_types::{
    TableName, TableOffset, TablePosition, TablePrimaryKeys,
};
use anyhow::Result;
use colored::Colorize;
use log::{debug, info};

use crate::diff::diff_output::DiffOutput;
use crate::diff::types::SchemaName;
use std::time::Instant;
use tracing::instrument;

pub struct TableDiffer<TQE: TableSingleSourceQueryExecutor, DTQE: TableDualSourceQueryExecutor> {
    single_table_query_executor: TQE,
    dual_table_query_executor: DTQE,
}

impl<TQE: TableSingleSourceQueryExecutor, DTQE: TableDualSourceQueryExecutor>
TableDiffer<TQE, DTQE>
{
    pub fn new(single_table_query_executor: TQE, dual_table_query_executor: DTQE) -> Self {
        Self {
            single_table_query_executor,
            dual_table_query_executor,
        }
    }

    #[instrument(skip(self, diff_payload), fields(schema_name = diff_payload.schema_name()))]
    pub async fn diff_all_table_data(&self, diff_payload: &DiffPayload) -> Result<Vec<DiffOutput>> {
        info!("{}", "Starting data analysis.".yellow().bold());

        let mut tables = self.get_all_tables(diff_payload).await?;

        tables.sort_by_key(|s| s.to_lowercase());

        let sorted_tables = tables.to_owned();

        let futures = sorted_tables.iter().map(|table_name| async {
            let start = Instant::now();

            // Start loading counts for table from both DBs
            let query_count_input = QueryTableCountInput::new(
                SchemaName::new(diff_payload.schema_name().to_string()),
                TableName::new(table_name.to_string()),
            );

            let table_counts_start = Instant::now();
            let (first_result, second_result) = self
                .dual_table_query_executor
                .query_table_count(query_count_input)
                .await;

            let table_counts_elapsed = table_counts_start.elapsed();
            debug!(
                "Table counts for {} loaded in: {}ms",
                table_name.clone(),
                table_counts_elapsed.as_millis()
            );

            info!(
                "{}",
                format!("Analyzing table: {}", table_name.clone())
                    .yellow()
                    .bold()
            );

            // Start counts comparison
            let table_diff_result = Self::extract_result(table_name, first_result, second_result);

            let elapsed = start.elapsed();
            debug!(
                "{}",
                format!("Table analysis completed in: {}ms", elapsed.as_millis())
            );

            info!("##############################################");

            // If we only care about counts, return the result
            if diff_payload.only_count() {
                return table_diff_result;
            }

            // If the diff result permits us to skip data comparison, return the result
            if table_diff_result.skip_table_diff() {
                return table_diff_result;
            }

            let query_primary_keys_input = QueryPrimaryKeysInput::new(table_name.clone());

            let primary_keys = self
                .single_table_query_executor
                .query_primary_keys(query_primary_keys_input)
                .await;

            // If no primary keys found, return the result
            if primary_keys.is_empty() {
                let table_diff_result = TableDiffOutput::NoPrimaryKeyFound(table_name.clone());
                return table_diff_result;
            }

            // Prepare the primary keys for the table
            // Will be used for query ordering when hashing data
            let primary_keys = primary_keys.as_slice().join(",");

            let total_rows = match table_diff_result {
                TableDiffOutput::NoCountDiff(_, rows) => rows,
                _ => {
                    // Since we do not expect to reach here, print the result and panic
                    panic!("Unexpected table diff result")
                }
            };

            let schema_name = SchemaName::new(diff_payload.schema_name().to_string());
            let query_table_name = TableName::new(table_name.clone());
            let table_offset = TableOffset::new(diff_payload.chunk_size());
            let table_primary_keys = TablePrimaryKeys::new(primary_keys);

            let start = Instant::now();

            if let Some(value) = self
                .diff_table_data(
                    diff_payload,
                    schema_name,
                    query_table_name,
                    table_offset,
                    table_primary_keys,
                    total_rows,
                    start,
                )
                .await
            {
                return value;
            }

            let elapsed = start.elapsed();

            TableDiffOutput::NoDiffWithDuration(table_name.clone(), elapsed)
        });

        info!(
            "{}",
            "Waiting for table analysis to complete.".yellow().bold()
        );
        let start = Instant::now();
        let analysed_tables = futures::future::join_all(futures).await;
        let elapsed = start.elapsed();
        info!(
            "{}",
            format!(
                "Total table analysis completed in: {}ms",
                elapsed.as_millis()
            )
            .yellow()
            .bold(),
        );
        info!(
            "{}",
            format!("Total tables for row count check: {}", tables.len())
                .bright_blue()
                .bold()
        );

        info!("##############################################");
        info!("{}", "Table analysis results 👇".bright_magenta().bold());

        for table_diff_result in &analysed_tables {
            info!("{}", table_diff_result.to_string());
        }

        info!("##############################################");

        Ok(
            analysed_tables
                .into_iter()
                .map(|diff| diff.into())
                .collect()
        )
    }

    pub async fn get_all_tables(&self, diff_payload: &DiffPayload) -> Result<Vec<String>> {
        let input = QueryTableNamesInput::new(
            SchemaName::new(diff_payload.schema_name().to_string()),
            diff_payload.included_tables().to_vec(),
        );
        let tables = self
            .single_table_query_executor
            .query_table_names(input)
            .await;
        Ok(tables)
    }

    fn extract_result(
        table_name: &str,
        first_result: Result<i64>,
        second_result: Result<i64>,
    ) -> TableDiffOutput {
        match (first_result, second_result) {
            (Ok(first_total_rows), Ok(second_total_rows)) => {
                if first_total_rows != second_total_rows {
                    TableDiffOutput::Diff(
                        table_name.to_owned(),
                        TableCountDiff::new(first_total_rows, second_total_rows),
                    )
                } else {
                    TableDiffOutput::NoCountDiff(table_name.to_owned(), first_total_rows)
                }
            }
            (Err(_e), _) => TableDiffOutput::NotExists(table_name.to_owned(), TableSource::First),
            (_, Err(_e)) => TableDiffOutput::NotExists(table_name.to_owned(), TableSource::Second),
        }
    }

    async fn diff_table_data(
        &self,
        diff_payload: &DiffPayload,
        schema_name: SchemaName,
        query_table_name: TableName,
        table_offset: TableOffset,
        table_primary_keys: TablePrimaryKeys,
        total_rows: i64,
        start: Instant,
    ) -> Option<TableDiffOutput> {
        // Start data comparison
        let mut position = 0;
        while position <= total_rows {
            let input = QueryHashDataInput::new(
                schema_name.clone(),
                query_table_name.clone(),
                table_primary_keys.clone(),
                TablePosition::new(position),
                table_offset.clone(),
            );

            let hash_fetch_start = Instant::now();
            let (first_hash, second_hash) =
                self.dual_table_query_executor.query_hash_data(input).await;
            let hash_fetch_elapsed = hash_fetch_start.elapsed();
            debug!(
                "Hashes for {} loaded in: {}ms",
                query_table_name.name(),
                hash_fetch_elapsed.as_millis()
            );

            // If hashes are different, return the result
            if first_hash != second_hash {
                let elapsed = start.elapsed();
                return Some(TableDiffOutput::DataDiffWithDuration(
                    query_table_name.name().to_string(),
                    position,
                    position + diff_payload.chunk_size(),
                    elapsed,
                ));
            }

            // Increase the position for the next iteration
            position += diff_payload.chunk_size();
        }

        None
    }
}