package count

import (
	"database/sql"
	"github.com/dannyvankooten/ana/db"
	"log"
	"time"
)

type Archive struct {
	ID     int64
	Metric string
	Value  string
	Count  int64
	Date   string
}

type Point struct {
	Label           string
	Value           int
	PercentageValue float64
}

func (a *Archive) Save(Conn *sql.DB) error {
	stmt, err := db.Conn.Prepare(`INSERT INTO archive(
    metric,
    value,
    count,
    date
    ) VALUES( ?, ?, ?, ? )`)
	if err != nil {
		return err
	}
	defer stmt.Close()

	result, err := stmt.Exec(
		a.Metric,
		a.Value,
		a.Count,
		a.Date,
	)
	a.ID, _ = result.LastInsertId()

	return err
}

func CreateArchives() {
	CreatePageviewArchives()
	CreateVisitorArchives()
}

func CreatePageviewArchives() {
	stmt, err := db.Conn.Prepare(`
    SELECT
      COUNT(*) AS count,
      DATE_FORMAT(pv.timestamp, "%Y-%m-%d") AS date_group
    FROM pageviews pv
    WHERE NOT EXISTS(
      SELECT a.id
      FROM archive a
      WHERE a.metric = 'pageviews' AND a.date = DATE_FORMAT(pv.timestamp, "%Y-%m-%d")
    )
    GROUP BY date_group`)
	checkError(err)
	defer stmt.Close()

	rows, err := stmt.Query()
	checkError(err)
	defer rows.Close()

	db.Conn.Exec("START TRANSACTION")
	for rows.Next() {
		a := Archive{
			Metric: "pageviews",
			Value:  "",
		}
		err = rows.Scan(&a.Count, &a.Date)
		checkError(err)
		a.Save(db.Conn)
	}
	db.Conn.Exec("COMMIT")
}

func CreateVisitorArchives() {
	stmt, err := db.Conn.Prepare(`
    SELECT
      COUNT(DISTINCT(pv.visitor_id)) AS count,
      DATE_FORMAT(pv.timestamp, "%Y-%m-%d") AS date_group
    FROM pageviews pv
    WHERE NOT EXISTS(
      SELECT a.id
      FROM archive a
      WHERE a.metric = 'visitors' AND a.date = DATE_FORMAT(pv.timestamp, "%Y-%m-%d")
    )
    GROUP BY date_group`)
	checkError(err)
	defer stmt.Close()

	rows, err := stmt.Query()
	checkError(err)
	defer rows.Close()

	db.Conn.Exec("START TRANSACTION")
	for rows.Next() {
		a := Archive{
			Metric: "visitors",
			Value:  "",
		}
		err = rows.Scan(&a.Count, &a.Date)
		checkError(err)
		a.Save(db.Conn)
	}
	db.Conn.Exec("COMMIT")
}

func checkError(err error) {
	if err != nil {
		log.Fatal(err)
	}
}

func Custom(sql string, before int64, after int64, limit int, total float64) []Point {
	stmt, err := db.Conn.Prepare(sql)
	checkError(err)
	defer stmt.Close()

	rows, err := stmt.Query(before, after, limit)
	checkError(err)
	defer rows.Close()

	results := newPointSlice(rows, total)
	return results
}

func newPointSlice(rows *sql.Rows, total float64) []Point {
	results := make([]Point, 0)
	for rows.Next() {
		var d Point
		err := rows.Scan(&d.Label, &d.Value)
		checkError(err)

		d.PercentageValue = float64(d.Value) / total * 100
		results = append(results, d)
	}

	return results
}

func fill(start int64, end int64, points []Point) []Point {
	// be smart about received timestamps
	if start > end {
		tmp := end
		end = start
		start = tmp
	}

	startTime := time.Unix(start, 0)
	endTime := time.Unix(end, 0)
	newPoints := make([]Point, 0)
	step := time.Hour * 24

	for startTime.Before(endTime) || startTime.Equal(endTime) {
		point := Point{
			Value: 0,
			Label: startTime.Format("2006-01-02"),
		}

		for j, p := range points {
			if p.Label == point.Label || p.Label == startTime.Format("2006-01") {
				point.Value = p.Value
				points[j] = points[len(points)-1]
				break
			}
		}

		newPoints = append(newPoints, point)
		startTime = startTime.Add(step)
	}

	return newPoints
}