package condition

import (
	"fmt"
	"strings"

	"git.fsdpf.net/go/db"
	"git.fsdpf.net/go/utils"
	"github.com/samber/lo"
)

type ConditionType string

const (
	OR  ConditionType = "OR"
	AND ConditionType = "AND"
)

type Condition struct {
	parent    *Condition
	typ       ConditionType    // 分组类型
	describe  string           // 描述
	exprs     []*ConditionExpr // 分组表达式成员
	childrens []*Condition     // 分组子集
}

func (this *Condition) AppendTo(c *Condition) {
	this.parent = c
}

// 条件类型
func (this Condition) Type() ConditionType {
	return this.typ
}

// 判断条件为空
func (this Condition) IsEmpty() bool {
	if len(this.exprs) > 0 {
		return false
	}
	for _, cond := range this.childrens {
		if !cond.IsEmpty() {
			return false
		}
	}
	return true
}

// 判断条件不为空
func (this Condition) IsNotEmpty() bool {
	return !this.IsEmpty()
}

// 判断条件是否恒成立
func (this Condition) IsAlwaysRight() bool {
	flag := []bool{}

	for _, expr := range this.exprs {
		if expr.GetOperator() != EQ {
			flag = append(flag, false)
			continue
		}

		if expr.GetTokenType() != SQL {
			flag = append(flag, false)
			continue
		}

		eRight := fmt.Sprintf("%s.%s", expr.GetFieldResource(), expr.GetField()) == strings.ReplaceAll(expr.GetTokenName(), "`", "")

		if this.typ == OR && eRight {
			return true
		}

		flag = append(flag, eRight)
	}

	for _, cond := range this.childrens {
		cRight := cond.IsAlwaysRight()

		if this.typ == OR && cRight {
			return true
		}

		flag = append(flag, cRight)
	}

	if len(flag) == 0 {
		return true
	}

	return !lo.Some(flag, []bool{false})
}

// 生成 SQL 语句
func (this Condition) ToSql(m TokenValue) db.Expression {
	conditions := []string{}
	// 表达式
	for _, item := range this.exprs {
		if item.IsIgnoreEmptyParma(m) {
			continue
		}
		conditions = append(conditions, string(item.ToSql(m)))
	}
	// 条件子集
	for _, item := range this.childrens {
		conditions = append(conditions, string(item.ToSql(m)))
	}
	// 去除无效的表达式
	conditions = lo.Filter(conditions, func(item string, _ int) bool { return item != "" })
	// 组合 SQL
	sql := strings.Join(conditions, " "+string(this.Type())+" ")

	if sql == "" {
		if this.parent == nil && this.Type() == OR {
			return db.Raw("false")
		} else if this.parent == nil && this.Type() == AND {
			return db.Raw("true")
		}
		return db.Raw("")
	}

	// 包裹 SQL, 避免语法表达错误
	if this.parent == nil || this.Type() == OR {
		sql = "(" + sql + ")"
	}

	if this.describe != "" {
		sql += "/*" + this.describe + "*/"
	}

	return db.Raw(sql)
}

// 设置条件表达式
func (this *Condition) SetExpr(expr *ConditionExpr) *Condition {
	expr.AppendTo(this)
	this.exprs = append(this.exprs, expr)
	return this
}

// 设置条件子集
func (this *Condition) SetCondition(c *Condition) *Condition {
	c.AppendTo(this)
	this.childrens = append(this.childrens, c)
	return this
}

// 设置 Token 匹配前缀
func (this *Condition) SetMatchPrefix(prefix string) *Condition {
	for _, expr := range this.exprs {
		expr.SetMatchPrefix(prefix)
	}
	for _, cond := range this.childrens {
		cond.SetMatchPrefix(prefix)
	}
	return this
}

func (this Condition) GetFieldsValue(m TokenValue, isWithResource bool) (result map[string]any) {
	if this.IsEmpty() {
		return
	}

	// 表达式
	for _, item := range this.exprs {
		if item.GetOperator() != EQ {
			continue
		}

		vField := map[string]any{item.GetField(): item.GetTokenValue(m)}

		if isWithResource {
			vField = map[string]any{item.GetFieldResource(): vField}
		}

		result = utils.MergeMap(result, vField)
	}
	// 条件子集
	for _, item := range this.childrens {
		result = utils.MergeMap(result, item.GetFieldsValue(m, isWithResource))
	}

	return result
}

/**
 * @param ConditionOperator operator
 * @param TokenType types
 * @return map[string][string] // 如: {"TestA.field_a": "param"}
 */
func (this Condition) GetFields(operator ConditionOperator, types ...TokenType) map[string]string {
	result := make(map[string]string)

	if this.IsEmpty() {
		return result
	}

	// 表达式
	for _, item := range this.exprs {
		if item.GetOperator() != operator || !lo.Contains(types, item.GetTokenType()) {
			continue
		}

		result[fmt.Sprintf("%s.%s", item.GetFieldResource(), item.GetField())] = item.GetTokenName()
	}

	// 条件子集
	for _, item := range this.childrens {
		result = lo.Assign(result, item.GetFields(operator, types...))
	}

	return result
}

func (this *Condition) SetOption(opts ...Option) *Condition {
	for i := 0; i < len(opts); i++ {
		opts[i](this)
	}
	return this
}

type Option func(option *Condition)

func Type(v ConditionType) Option {
	return func(option *Condition) {
		option.typ = v
	}
}

func Describe(v string) Option {
	return func(option *Condition) {
		option.describe = v
	}
}

func New(opts ...Option) *Condition {
	cond := &Condition{typ: AND}
	cond.SetOption(opts...)
	return cond
}