package Database

import (
	"database/sql"
	"time"
)

type FilesystemHashRow struct {
	Path      string
	Hash      string
	UpdatedAt time.Time
}

func FindOrCreateFileHash(rows []FilesystemHashRow) error {
	var (
		stmtString string
		stmt       *sql.Stmt
		values     []interface{} = []interface{}{}
		e          error
	)

	stmtString = "INSERT OR REPLACE INTO filesystem_hash (id, path, hash, updated_at) VALUES "

	for _, row := range rows {
		stmtString += `(
				(SELECT id FROM filesystem_hash WHERE path = ?),
				?,
				?,
				?
			),`
		values = append(values, row.Path, row.Path, row.Hash, row.UpdatedAt.Unix())
	}

	stmtString = stmtString[0 : len(stmtString)-1]

	stmt, e = DB.Prepare(stmtString)
	if e != nil {
		return e
	}

	_, e = stmt.Exec(values...)

	return e
}

func FindModifiedFiles(hashes []string) (map[int]string, error) {
	var (
		stmtString string
		stmt       *sql.Stmt
		values     []interface{} = []interface{}{}
		result     *sql.Rows
		dirtyFiles map[int]string = make(map[int]string)
		counter    int            = 0
		e          error
	)

	stmtString = "SELECT id, path FROM filesystem_hash WHERE hash NOT IN ("

	for _, row := range hashes {
		stmtString += "?,"
		values = append(values, row)
	}

	stmtString = stmtString[0:len(stmtString)-1] + ")"

	stmt, e = DB.Prepare(stmtString)
	if e != nil {
		return dirtyFiles, e
	}

	result, e = stmt.Query(values...)
	if e != nil {
		return dirtyFiles, e
	}

	defer result.Close()
	for result.Next() {
		var id string
		var path string
		e = result.Scan(&id, &path)
		if e != nil {
			return dirtyFiles, e
		}
		dirtyFiles[counter] = path
		counter++
	}

	e = result.Err()
	return dirtyFiles, e
}

func GetMostRecentTimestamp() (time.Time, error) {
	var (
		stmt          *sql.Stmt
		result        *sql.Row
		lastUpdatedAt int64
		e             error
	)

	stmt, e = DB.Prepare(`
	SELECT updated_at FROM filesystem_hash
	ORDER BY updated_at DESC
	LIMIT 1;
	`)
	if e != nil {
		return time.Now(), e
	}

	result = stmt.QueryRow()

	result.Scan(&lastUpdatedAt)

	return time.Unix(lastUpdatedAt, 0), nil
}