Fs02/grimoire

// Package sql is general sql adapter that wraps database/sql.
package sql

import (
    "database/sql"
    "strconv"
    "time"

    "github.com/Fs02/grimoire"
    "github.com/Fs02/grimoire/errors"
)

// Config holds configuration for adapter.
type Config struct {
    Placeholder         string
    Ordinal             bool
    InsertDefaultValues bool
    EscapeChar          string
    ErrorFunc           func(error) error
    IncrementFunc       func(Adapter) int
}

// Adapter definition for mysql database.
type Adapter struct {
    Config    *Config
    DB        *sql.DB
    Tx        *sql.Tx
    savepoint int
}

var _ grimoire.Adapter = (*Adapter)(nil)

// Close mysql connection.
func (adapter *Adapter) Close() error {
    return adapter.DB.Close()
}

// All retrieves all record that match the query.
func (adapter *Adapter) All(query grimoire.Query, doc interface{}, loggers ...grimoire.Logger) (int, error) {
    statement, args := NewBuilder(adapter.Config).Find(query)
    count, err := adapter.Query(doc, statement, args, loggers...)
    return int(count), err
}

// Aggregate record using given query.
func (adapter *Adapter) Aggregate(query grimoire.Query, doc interface{}, loggers ...grimoire.Logger) error {
    statement, args := NewBuilder(adapter.Config).Aggregate(query)
    _, err := adapter.Query(doc, statement, args, loggers...)
    return err
}

// Insert inserts a record to database and returns its id.
func (adapter *Adapter) Insert(query grimoire.Query, changes map[string]interface{}, loggers ...grimoire.Logger) (interface{}, error) {
    statement, args := NewBuilder(adapter.Config).Insert(query.Collection, changes)
    id, _, err := adapter.Exec(statement, args, loggers...)
    return id, err
}

// InsertAll inserts all record to database and returns its ids.
func (adapter *Adapter) InsertAll(query grimoire.Query, fields []string, allchanges []map[string]interface{}, loggers ...grimoire.Logger) ([]interface{}, error) {
    statement, args := NewBuilder(adapter.Config).InsertAll(query.Collection, fields, allchanges)
    id, _, err := adapter.Exec(statement, args, loggers...)
    if err != nil {
        return nil, err
    }

    var (
        ids = []interface{}{id}
        inc = 1
    )

    if adapter.Config.IncrementFunc != nil {
        inc = adapter.Config.IncrementFunc(*adapter)
    }

    for i := 1; i < len(allchanges); i++ {
        ids = append(ids, id+int64(inc*i))
    }

    return ids, nil
}

// Update updates a record in database.
func (adapter *Adapter) Update(query grimoire.Query, changes map[string]interface{}, loggers ...grimoire.Logger) error {
    statement, args := NewBuilder(adapter.Config).Update(query.Collection, changes, query.Condition)
    _, _, err := adapter.Exec(statement, args, loggers...)
    return err
}

// Delete deletes all results that match the query.
func (adapter *Adapter) Delete(query grimoire.Query, loggers ...grimoire.Logger) error {
    statement, args := NewBuilder(adapter.Config).Delete(query.Collection, query.Condition)
    _, _, err := adapter.Exec(statement, args, loggers...)
    return err
}

// Begin begins a new transaction.
func (adapter *Adapter) Begin() (grimoire.Adapter, error) {
    var (
        tx        *sql.Tx
        savepoint int
        err       error
    )

    if adapter.Tx != nil {
        tx = adapter.Tx
        savepoint = adapter.savepoint + 1
        _, _, err = adapter.Exec("SAVEPOINT s"+strconv.Itoa(savepoint)+";", []interface{}{})
    } else {
        tx, err = adapter.DB.Begin()
    }

    return &Adapter{
        Config:    adapter.Config,
        Tx:        tx,
        savepoint: savepoint,
    }, err
}

// Commit commits current transaction.
func (adapter *Adapter) Commit() error {
    var err error

    if adapter.Tx == nil {
        err = errors.NewUnexpected("unable to commit outside transaction")
    } else if adapter.savepoint > 0 {
        _, _, err = adapter.Exec("RELEASE SAVEPOINT s"+strconv.Itoa(adapter.savepoint)+";", []interface{}{})
    } else {
        err = adapter.Tx.Commit()
    }

    return adapter.Config.ErrorFunc(err)
}

// Rollback revert current transaction.
func (adapter *Adapter) Rollback() error {
    var err error

    if adapter.Tx == nil {
        err = errors.NewUnexpected("unable to rollback outside transaction")
    } else if adapter.savepoint > 0 {
        _, _, err = adapter.Exec("ROLLBACK TO SAVEPOINT s"+strconv.Itoa(adapter.savepoint)+";", []interface{}{})
    } else {
        err = adapter.Tx.Rollback()
    }

    return adapter.Config.ErrorFunc(err)
}

// Query performs query operation.
func (adapter *Adapter) Query(out interface{}, statement string, args []interface{}, loggers ...grimoire.Logger) (int64, error) {
    var (
        rows *sql.Rows
        err  error
    )

    start := time.Now()
    if adapter.Tx != nil {
        rows, err = adapter.Tx.Query(statement, args...)
    } else {
        rows, err = adapter.DB.Query(statement, args...)
    }

    go grimoire.Log(loggers, statement, time.Since(start), err)

    if err != nil {
        return 0, adapter.Config.ErrorFunc(err)
    }

    defer rows.Close()
    count, err := Scan(out, rows)
    return count, adapter.Config.ErrorFunc(err)
}

// Exec performs exec operation.
func (adapter *Adapter) Exec(statement string, args []interface{}, loggers ...grimoire.Logger) (int64, int64, error) {
    var (
        res sql.Result
        err error
    )

    start := time.Now()
    if adapter.Tx != nil {
        res, err = adapter.Tx.Exec(statement, args...)
    } else {
        res, err = adapter.DB.Exec(statement, args...)
    }

    go grimoire.Log(loggers, statement, time.Since(start), err)

    if err != nil {
        return 0, 0, adapter.Config.ErrorFunc(err)
    }

    lastID, _ := res.LastInsertId()
    rowCount, _ := res.RowsAffected()

    return lastID, rowCount, nil
}

// New initialize adapter without db.
func New(config *Config) *Adapter {
    adapter := &Adapter{
        Config: config,
    }

    return adapter
}