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")
		return nil, err
	}

	return s, nil
}

// todo toanaliz for keydevice,keydevicetype,keybrowser,
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) AS
SELECT
    event_time, ctxsession, ctxquizid, ctxquestionid, ctxidint, message, keyos,
    ctxuserip, ctxuserport, keydomain, keypath, ctxquiz, ctxreferrer
FROM (SELECT
            event_time, ctxsession, ctxquizid, ctxquestionid, ctxidint, message, keyos,
            ctxuserip, ctxuserport, keydomain, keypath, ctxquiz, ctxreferrer,
            row_number() OVER (PARTITION BY ctxsession ORDER BY event_time DESC) as row_num
        FROM statistics
        WHERE message IN ('InfoQuizOpen', 'InfoAnswer', 'InfoResult') AND event_level = 'info') AS sorted
WHERE row_num = 1;
`
	_, err := s.conn.ExecContext(ctx, query)
	if err != nil {
		return err
	}
	return nil
}

type Statistic struct {
	Count      int64
	QuestionID int64
}

type PipeLineStatsResp [][]Statistic

func (s *StatisticClick) GetPipelinesStatistics(ctx context.Context, quizID int64, from uint64, to uint64) (PipeLineStatsResp, error) {
	query := `
SELECT
    ctxsession,ctxquestionid,count(*) as session_count
FROM mv_last_answers_events WHERE ctxquizid = ? AND event_time BETWEEN ? AND ?
GROUP BY ctxsession, ctxquestionid ORDER BY ctxsession, ctxquestionid
`
	rows, err := s.conn.QueryContext(ctx, query, quizID, from, to)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var pipelines PipeLineStatsResp
	var currentPipeline []Statistic
	var lastSession string

	for rows.Next() {
		var session string
		var questionID int64
		var count int64
		err := rows.Scan(&session, &questionID, &count)
		if err != nil {
			return nil, err
		}

		// новая сессия - новая воронка
		if session != lastSession {
			if lastSession != "" {
				pipelines = append(pipelines, currentPipeline)
			}
			currentPipeline = []Statistic{}
		}

		// текущая статистика в текущую воронку
		currentPipeline = append(currentPipeline, Statistic{
			Count:      count,
			QuestionID: questionID,
		})

		lastSession = session
	}

	// последня воронка если есть то добавляем
	if len(currentPipeline) > 0 {
		pipelines = append(pipelines, currentPipeline)
	}

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

	return pipelines, nil
}