package db

import (
	"database/sql"

	"github.com/lbryio/reflector.go/types"

	"github.com/lbryio/errors.go"
	qtools "github.com/lbryio/query.go"

	_ "github.com/go-sql-driver/mysql"
	log "github.com/sirupsen/logrus"
)

type DB interface {
	Connect(string) error
	HasBlob(string) (bool, error)
	AddBlob(string, int, bool) error
	AddSDBlob(string, int, types.SdBlob) error
}

type SQL struct {
	conn *sql.DB
}

func logQuery(query string, args ...interface{}) {
	s, err := qtools.InterpolateParams(query, args...)
	if err != nil {
		log.Errorln(err)
	} else {
		log.Debugln(s)
	}
}

func (s *SQL) Connect(dsn string) error {
	var err error
	dsn += "?parseTime=1&collation=utf8mb4_unicode_ci"
	s.conn, err = sql.Open("mysql", dsn)
	if err != nil {
		return errors.Err(err)
	}

	return errors.Err(s.conn.Ping())
}

func (s *SQL) AddBlob(hash string, length int, stored bool) error {
	if s.conn == nil {
		return errors.Err("not connected")
	}

	if length <= 0 {
		return errors.Err("length must be positive")
	}

	query := "INSERT INTO blob_ (hash, stored, length) VALUES (?,?,?) ON DUPLICATE KEY UPDATE stored = (stored or VALUES(stored))"
	args := []interface{}{hash, stored, length}

	logQuery(query, args...)

	stmt, err := s.conn.Prepare(query)
	if err != nil {
		return errors.Err(err)
	}

	_, err = stmt.Exec(args...)
	if err != nil {
		return errors.Err(err)
	}

	return nil
}

func (s *SQL) HasBlob(hash string) (bool, error) {
	if s.conn == nil {
		return false, errors.Err("not connected")
	}

	query := "SELECT EXISTS(SELECT 1 FROM blob_ WHERE hash = ? AND stored = ?)"
	args := []interface{}{hash, true}

	logQuery(query, args...)

	row := s.conn.QueryRow(query, args...)

	exists := false
	err := row.Scan(&exists)

	return exists, errors.Err(err)
}

func (s *SQL) AddSDBlob(sdHash string, sdBlobLength int, sdBlob types.SdBlob) error {
	if s.conn == nil {
		return errors.Err("not connected")
	}

	// TODO: should do all this in transaction

	// insert sd blob
	err := s.AddBlob(sdHash, sdBlobLength, true)
	if err != nil {
		return err
	}

	// insert stream
	query := "INSERT IGNORE INTO stream (hash, sd_hash) VALUES (?,?)"
	args := []interface{}{sdBlob.StreamHash, sdHash}

	logQuery(query, args...)

	stmt, err := s.conn.Prepare(query)
	if err != nil {
		return errors.Err(err)
	}

	_, err = stmt.Exec(args...)
	if err != nil {
		return errors.Err(err)
	}

	// insert content blobs and connect them to stream
	for _, contentBlob := range sdBlob.Blobs {
		if contentBlob.BlobHash == "" {
			// null terminator blob
			continue
		}

		err := s.AddBlob(contentBlob.BlobHash, contentBlob.Length, false)
		if err != nil {
			return err
		}

		query := "INSERT IGNORE INTO stream_blob (stream_hash, blob_hash, num) VALUES (?,?,?)"
		args := []interface{}{sdBlob.StreamHash, contentBlob.BlobHash, contentBlob.BlobNum}

		logQuery(query, args...)

		stmt, err := s.conn.Prepare(query)
		if err != nil {
			return errors.Err(err)
		}

		_, err = stmt.Exec(args...)
		if err != nil {
			return errors.Err(err)
		}
	}

	return nil
}

func schema() {
	_ = `
CREATE TABLE blob_ (
  hash char(96) NOT NULL,
  stored TINYINT(1) NOT NULL DEFAULT 0,
  length bigint(20) unsigned DEFAULT NULL,
  last_announced_at datetime DEFAULT NULL,
  PRIMARY KEY (hash),
  KEY last_announced_at_idx (last_announced_at)
) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

CREATE TABLE stream (
  hash char(96) NOT NULL,
  sd_hash char(96) NOT NULL,
  PRIMARY KEY (hash),
  KEY sd_hash_idx (sd_hash),
  FOREIGN KEY (sd_hash) REFERENCES blob_ (hash) ON DELETE RESTRICT ON UPDATE CASCADE
) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

CREATE TABLE stream_blob (
  stream_hash char(96) NOT NULL,
  blob_hash char(96) NOT NULL,
  num int NOT NULL,
  PRIMARY KEY (stream_hash, blob_hash),
  FOREIGN KEY (stream_hash) REFERENCES stream (hash) ON DELETE CASCADE ON UPDATE CASCADE,
  FOREIGN KEY (blob_hash) REFERENCES blob_ (hash) ON DELETE CASCADE ON UPDATE CASCADE
) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

`
}