package statistics

import (
	"context"
	"database/sql"
	"fmt"
)

type DepsClick struct {
	Conn *sql.DB
}

type StatisticClick struct {
	conn *sql.DB
}

func NewClickStatistic(ctx context.Context, deps DepsClick) (*StatisticClick, error) {
	s := &StatisticClick{
		conn: deps.Conn,
	}

	err := s.checkMW(ctx)
	if err != nil {
		fmt.Println("error check material view existing", err)
		return nil, err
	}

	return s, nil
}

func (s *StatisticClick) checkMW(ctx context.Context) error {
	query := `
CREATE MATERIALIZED VIEW IF NOT EXISTS mv_last_answers_events
ENGINE = MergeTree()
ORDER BY (ctxsession, event_time) POPULATE AS
SELECT
    event_time, ctxsession, ctxquizid, ctxquestionid, ctxidint, message,ctxquiz
FROM statistics
WHERE message IN ('InfoQuizOpen', 'InfoAnswer', 'InfoResult') AND event_level = 'info';
`
	_, err := s.conn.ExecContext(ctx, query)
	if err != nil {
		return err
	}
	return nil
}

type Statistic struct {
	Count      int64
	QuestionID int64
}

type PipeLineStatsResp map[int64][]Statistic

func (s *StatisticClick) GetPipelinesStatistics(ctx context.Context, quizID int64, from uint64, to uint64) (PipeLineStatsResp, error) {
	pipelines := make(PipeLineStatsResp)

	query := `
		select last_quesion, questions, count() from (select last_quesion, questions, target_quiz
      from (select last_quesion, questions, target_quiz from view_pipelines_signs
          join view_respondent_paths on long_sess = session array join questions)
          as pipelines join mv_answers on questions=questionid and quizid=target_quiz
      where target_quiz = ? AND event_time BETWEEN ? AND ? ) group by last_quesion, questions;
	`

	rows, err := s.conn.QueryContext(ctx, query, quizID, from, to)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	for rows.Next() {
		var lastQuestionID int64
		var questionID int64
		var count int64

		if err := rows.Scan(&lastQuestionID, &questionID, &count); err != nil {
			return nil, err
		}

		stat := Statistic{
			Count:      count,
			QuestionID: questionID,
		}

		pipelines[lastQuestionID] = append(pipelines[lastQuestionID], stat)
	}

	if err := rows.Err(); err != nil {
		return nil, err
	}

	return pipelines, nil
}