package sqlite3

import (
	"database/sql"
	"regexp"
	"time"

	"git.fsdpf.net/go/db"
	"git.fsdpf.net/go/db/exp"
	gosqlite3 "github.com/mattn/go-sqlite3"
)

// DriverWithIF 是注册了 IF() 函数的 SQLite3 驱动名称。
// 使用该驱动名打开连接时，可在 SQL 中直接使用 IF(condition, trueVal, falseVal)。
const DriverWithIF = "sqlite3_with_if"

func DialectOptions() *db.SQLDialectOptions {
	opts := db.DefaultDialectOptions()

	opts.SupportsReturn = true
	opts.SupportsOrderByOnUpdate = true
	opts.SupportsLimitOnUpdate = true
	opts.SupportsOrderByOnDelete = true
	opts.SupportsLimitOnDelete = true
	opts.SupportsConflictUpdateWhere = false
	opts.SupportsInsertIgnoreSyntax = true
	opts.SupportsConflictTarget = true
	opts.SupportsMultipleUpdateTables = false
	opts.WrapCompoundsInParens = false
	opts.SupportsDistinct = true // 设为 false 可全局禁止生成 DISTINCT 关键字
	opts.SupportsDistinctOn = false
	opts.SupportsWindowFunction = false
	opts.SupportsLateral = false

	opts.PlaceHolderFragment = []byte("?")
	opts.IncludePlaceholderNum = false
	opts.QuoteRune = '`'
	opts.DefaultValuesFragment = []byte("")
	opts.True = []byte("1")
	opts.False = []byte("0")
	opts.TimeFormat = time.RFC3339Nano
	opts.BooleanOperatorLookup = map[exp.BooleanOperation][]byte{
		exp.EqOp:             []byte("="),
		exp.NeqOp:            []byte("!="),
		exp.GtOp:             []byte(">"),
		exp.GteOp:            []byte(">="),
		exp.LtOp:             []byte("<"),
		exp.LteOp:            []byte("<="),
		exp.InOp:             []byte("IN"),
		exp.NotInOp:          []byte("NOT IN"),
		exp.IsOp:             []byte("IS"),
		exp.IsNotOp:          []byte("IS NOT"),
		exp.LikeOp:           []byte("LIKE"),
		exp.NotLikeOp:        []byte("NOT LIKE"),
		exp.ILikeOp:          []byte("LIKE"),
		exp.NotILikeOp:       []byte("NOT LIKE"),
		exp.RegexpLikeOp:     []byte("REGEXP"),
		exp.RegexpNotLikeOp:  []byte("NOT REGEXP"),
		exp.RegexpILikeOp:    []byte("REGEXP"),
		exp.RegexpNotILikeOp: []byte("NOT REGEXP"),
	}
	opts.UseLiteralIsBools = false
	opts.BitwiseOperatorLookup = map[exp.BitwiseOperation][]byte{
		exp.BitwiseOrOp:         []byte("|"),
		exp.BitwiseAndOp:        []byte("&"),
		exp.BitwiseLeftShiftOp:  []byte("<<"),
		exp.BitwiseRightShiftOp: []byte(">>"),
	}
	opts.EscapedRunes = map[rune][]byte{
		'\'': []byte("''"),
	}
	opts.InsertIgnoreClause = []byte("INSERT OR IGNORE INTO ")
	opts.ConflictFragment = []byte(" ON CONFLICT ")
	opts.ConflictDoUpdateFragment = []byte(" DO UPDATE SET ")
	opts.ConflictDoNothingFragment = []byte(" DO NOTHING ")
	opts.ForUpdateFragment = []byte("")
	opts.OfFragment = []byte("")
	opts.NowaitFragment = []byte("")
	return opts
}

func init() {
	sql.Register(DriverWithIF, &gosqlite3.SQLiteDriver{
		ConnectHook: func(conn *gosqlite3.SQLiteConn) error {
			if err := conn.RegisterFunc("IF", func(cond int64, trueVal, falseVal interface{}) interface{} {
				if cond != 0 {
					return trueVal
				}
				return falseVal
			}, true); err != nil {
				return err
			}

			if err := conn.RegisterFunc("REGEXP", func(expr, item string) (bool, error) {
				return regexp.MatchString(expr, item)
			}, true); err != nil {
				return err
			}

			return nil
		},
	})
	db.RegisterDialect("sqlite3", DialectOptions())
}