package gorm

import (
	"bytes"
	"fmt"
	"strings"
	"sync"
)

// Copied from golint
var commonInitialisms = []string{"API", "ASCII", "CPU", "CSS", "DNS", "EOF", "GUID", "HTML", "HTTP", "HTTPS", "ID", "IP", "JSON", "LHS", "QPS", "RAM", "RHS", "RPC", "SLA", "SMTP", "SSH", "TLS", "TTL", "UI", "UID", "UUID", "URI", "URL", "UTF8", "VM", "XML", "XSRF", "XSS"}
var commonInitialismsReplacer *strings.Replacer

func init() {
	var commonInitialismsForReplacer []string
	for _, initialism := range commonInitialisms {
		commonInitialismsForReplacer = append(commonInitialismsForReplacer, initialism, strings.Title(strings.ToLower(initialism)))
	}
	commonInitialismsReplacer = strings.NewReplacer(commonInitialismsForReplacer...)
}

type safeMap struct {
	m map[string]string
	l *sync.RWMutex
}

func (s *safeMap) Set(key string, value string) {
	s.l.Lock()
	defer s.l.Unlock()
	s.m[key] = value
}

func (s *safeMap) Get(key string) string {
	s.l.RLock()
	defer s.l.RUnlock()
	return s.m[key]
}

func newSafeMap() *safeMap {
	return &safeMap{l: new(sync.RWMutex), m: make(map[string]string)}
}

var smap = newSafeMap()

type strCase bool

const (
	lower strCase = false
	upper strCase = true
)

func ToDBName(name string) string {
	if v := smap.Get(name); v != "" {
		return v
	}

	if name == "" {
		return ""
	}

	var (
		value                        = commonInitialismsReplacer.Replace(name)
		buf                          = bytes.NewBufferString("")
		lastCase, currCase, nextCase strCase
	)

	for i, v := range value[:len(value)-1] {
		nextCase = value[i+1] >= 'A' && value[i+1] <= 'Z'
		if i > 0 {
			if currCase == upper {
				if lastCase == upper && nextCase == upper {
					buf.WriteRune(v)
				} else {
					buf.WriteRune('_')
					buf.WriteRune(v)
				}
			} else {
				buf.WriteRune(v)
			}
		} else {
			currCase = upper
			buf.WriteRune(v)
		}
		lastCase = currCase
		currCase = nextCase
	}

	buf.WriteByte(value[len(value)-1])

	s := strings.Replace(strings.ToLower(buf.String()), "__", "_", -1)

	smap.Set(name, s)
	return s
}

type expr struct {
	expr string
	args []interface{}
}

func Expr(expression string, args ...interface{}) *expr {
	return &expr{expr: expression, args: args}
}

func toQueryMarks(primaryValues [][]interface{}) string {
	var results []string

	for _, primaryValue := range primaryValues {
		var marks []string
		for _ = range primaryValue {
			marks = append(marks, "?")
		}

		if len(marks) > 1 {
			results = append(results, fmt.Sprintf("(%v)", strings.Join(marks, ",")))
		} else {
			results = append(results, strings.Join(marks, ""))
		}
	}
	return strings.Join(results, ",")
}

func toQueryCondition(scope *Scope, columns []string) string {
	var newColumns []string
	for _, column := range columns {
		newColumns = append(newColumns, scope.Quote(column))
	}

	if len(columns) > 1 {
		return fmt.Sprintf("(%v)", strings.Join(newColumns, ","))
	}
	return strings.Join(newColumns, ",")
}

func toQueryValues(values [][]interface{}) (results []interface{}) {
	for _, value := range values {
		for _, v := range value {
			results = append(results, v)
		}
	}
	return
}