package meteo

import (
	"context"
	"fmt"

	b "github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
)

type Repository interface {
	InsertMeteoDataTX(ctx context.Context, params InsertMeteoDataParams) (*InsertMeteoDataResult, error)
	UpdateBatchElapsedTime(ctx context.Context, batchID int, elapsedMS int) error
	GetMeteoData(ctx context.Context, params GetMeteoData) ([]MeteoData, error)
}

type pgxRepo struct {
	*pgxpool.Pool
}

func NewPGXRepo(pool *pgxpool.Pool) Repository {
	return &pgxRepo{
		pool,
	}
}

type InsertMeteoDataParams struct {
	FileChecksum string
	Accepted     []MeteoData
	Rejected     []RejectedMeteoData
}

type InsertMeteoDataResult struct {
	BatchID       int
	AcceptedCount int
	RejectedCount int
}

func (pgx *pgxRepo) InsertMeteoDataTX(ctx context.Context, params InsertMeteoDataParams) (*InsertMeteoDataResult, error) {
	tx, err := pgx.Begin(ctx)
	if err != nil {
		return nil, fmt.Errorf("error starting transaction: %w", err)
	}
	defer tx.Rollback(ctx)

	batchID, err := pgx.insertBatch(ctx, tx, params.FileChecksum)
	if err != nil {
		return nil, err
	}

	acceptedCount, err := pgx.insertAcceptedMeteoData(ctx, tx, batchID, params.Accepted)
	if err != nil {
		return nil, err
	}

	rejectedCount, err := pgx.insertRejectedMeteoData(ctx, tx, batchID, params.Rejected)
	if err != nil {
		return nil, err
	}

	if err = tx.Commit(ctx); err != nil {
		return nil, fmt.Errorf("error committing transaction: %w", err)
	}

	return &InsertMeteoDataResult{
		BatchID:       batchID,
		AcceptedCount: acceptedCount,
		RejectedCount: rejectedCount,
	}, nil
}

const insertBatch = `insert into public.ingest_batch (elapsed_ms, file_checksum) values ($1, $2) returning id`

func (pgx *pgxRepo) insertBatch(ctx context.Context, tx b.Tx, fileChecksum string) (int, error) {
	var batchID int
	err := tx.QueryRow(ctx, insertBatch, 0, fileChecksum).Scan(&batchID)
	if err != nil {
		return 0, fmt.Errorf("error inserting batch: %w", err)
	}
	return batchID, nil
}

const insertAcceptedMeteoData = `insert into public.meteo_data (batch_id, location_name, date_of_register, max_temp, min_temp, rainfall, cloudiness) values ($1, $2, $3, $4, $5, $6, $7) returning id`

func (pgx *pgxRepo) insertAcceptedMeteoData(ctx context.Context, tx b.Tx, batchID int, data []MeteoData) (int, error) {
	if len(data) == 0 {
		return 0, nil
	}

	batch := &b.Batch{}

	for _, d := range data {
		batch.Queue(insertAcceptedMeteoData, batchID, d.Location, d.Timestamp, d.MaxTemp, d.MinTemp, d.Rainfall, d.Cloudiness)
	}

	results := tx.SendBatch(ctx, batch)

	var rowsInserted int
	for i := range data {
		_, err := results.Exec()
		rowsInserted++
		if err != nil {
			results.Close()
			return 0, fmt.Errorf("error executing batch command %d: %w", i, err)
		}
	}

	results.Close()

	return rowsInserted, nil
}

const insertRejectedMeteoData = `insert into public.rejected_data (batch_id, raw_data, reason) values ($1, $2, $3) returning id`

func (pgx *pgxRepo) insertRejectedMeteoData(ctx context.Context, tx b.Tx, batchID int, data []RejectedMeteoData) (int, error) {
	if len(data) == 0 {
		return 0, nil
	}

	batch := &b.Batch{}

	for _, d := range data {
		batch.Queue(insertRejectedMeteoData, batchID, d.RowValue, d.Reason)
	}

	results := tx.SendBatch(ctx, batch)

	var rowsInserted int
	for i := range data {
		_, err := results.Exec()
		rowsInserted++
		if err != nil {
			results.Close()
			return 0, fmt.Errorf("error executing batch command %d: %w", i, err)
		}
	}

	results.Close()

	return rowsInserted, nil
}

const updateBatchElapsedTime = `update public.ingest_batch set elapsed_ms = $1 where id = $2`

func (pgx *pgxRepo) UpdateBatchElapsedTime(ctx context.Context, batchID int, elapsedMS int) error {
	_, err := pgx.Exec(ctx, updateBatchElapsedTime, elapsedMS, batchID)
	if err != nil {
		return fmt.Errorf("error updating batch elapsed time: %w", err)
	}
	return nil
}

const getMeteoDataQuery = `
	select location_name, date_of_register, max_temp, min_temp, rainfall, cloudiness
	from public.meteo_data
	where location_name = $1
		and date_of_register >= $2
		and date_of_register <= $3
	order by date_of_register desc
	limit $4 offset $5
`

func (pgx *pgxRepo) GetMeteoData(ctx context.Context, params GetMeteoData) ([]MeteoData, error) {
	rows, err := pgx.Query(ctx, getMeteoDataQuery, params.Location, params.From, params.To, params.Limit, params.Offset)
	if err != nil {
		return nil, fmt.Errorf("error querying meteo data: %w", err)
	}
	defer rows.Close()

	var results []MeteoData
	for rows.Next() {
		var data MeteoData
		err := rows.Scan(
			&data.Location,
			&data.Timestamp,
			&data.MaxTemp,
			&data.MinTemp,
			&data.Rainfall,
			&data.Cloudiness,
		)
		if err != nil {
			return nil, fmt.Errorf("error scanning row: %w", err)
		}
		results = append(results, data)
	}

	if err = rows.Err(); err != nil {
		return nil, fmt.Errorf("error iterating rows: %w", err)
	}

	return results, nil
}