package builder

import (
	"fmt"
	"strings"
)

type Builder struct {
	TableName  string
	TableAlias string
	Parts      SQLParts
	Ctx        Context
}

type SQLParts struct {
	Operation string
	From      string
	FieldsExp string
	FromExp   string
	HavingExp string
	FiterExp  string
	JoinExps  []string
	GroupExp  string
	OrderExp  string
	LimitExp  string
	OffsetExp string
	Insert    InsertData
	Update    UpdateData
}

func New(ctx Context) *Builder {
	return &Builder{
		Parts: SQLParts{
			Operation: "SELECT",
			From:      "FROM",
		},
		Ctx: ctx,
	}
}

func (b *Builder) In(table string) *Builder {
	b.TableName, b.TableAlias = getTableAlias(table)
	b.Parts.FromExp = table
	b.Ctx = b.Ctx.New(CtxOpts{
		"TableName":  b.TableName,
		"TableAlias": b.TableAlias,
	})
	return b
}

func (b *Builder) Find(query Find) *Builder {
	b.Parts.FiterExp = covertFind(
		b.Ctx,
		query,
	)
	if b.Parts.Operation == "" {
		b.Parts.Operation = "SELECT"
	}
	if b.Parts.HavingExp == "" {
		b.Parts.HavingExp = "WHERE"
	}
	if b.Parts.FieldsExp == "" {
		b.Parts.FieldsExp = "*"
	}
	return b
}

func (b *Builder) Select(fields ...Map) *Builder {
	fieldsExp, err := convertFields(fields)
	if err != nil {
		return b
	}
	b.Parts.FieldsExp = fieldsExp
	return b
}

func (b *Builder) Fields(fields ...Map) *Builder {
	return b.Select(fields...)
}

func (b *Builder) Join(joins ...interface{}) *Builder {
	b.Parts.JoinExps = convertJoin(b.Ctx, joins...)
	return b
}

func (b *Builder) Group(keys ...string) *Builder {
	b.Parts.HavingExp = "HAVING"
	b.Parts.GroupExp = convertGroup(b.Ctx, keys)
	return b
}

func (b *Builder) Sort(sort Map) *Builder {
	b.Parts.OrderExp, _ = convertSort(b.Ctx, sort)
	return b
}

func (b *Builder) Limit(limit int) *Builder {
	b.Parts.LimitExp = fmt.Sprintf("LIMIT %d", limit)
	return b
}

func (b *Builder) Offset(offset int) *Builder {
	b.Parts.OffsetExp = fmt.Sprintf("OFFSET %d", offset)
	return b
}

func (b *Builder) Delete() *Builder {
	b.Parts.Operation = "DELETE"
	return b
}

func (b *Builder) Insert(inserts []Map) *Builder {
	insertData, _ := convertInsert(b.Ctx, inserts)
	b.Parts = SQLParts{
		Operation: "INSERT INTO",
		Insert:    insertData,
	}
	return b
}

func (b *Builder) Set(updates Map) *Builder {
	updateData := convertUpdate(b.Ctx, updates)
	b.Parts = SQLParts{
		Operation: "UPDATE",
		Update:    updateData,
	}
	return b
}

func (b *Builder) Update(updates Map) *Builder {
	return b.Set(updates)
}

func (b *Builder) OnConflict(fields ...string) *Builder {
	if b.Parts.Operation == "UPDATE" {
		b.Parts.Update.Upsert = convertConflict(b.Ctx, fields...)
		b.Parts.Update.UpsertExp = "DO NOTHING"
	} else {
		panic("OnConflict is only available for UPDATE operation")
	}
	return b
}

func (b *Builder) DoUpdate(fields ...string) *Builder {
	if b.Parts.Operation == "UPDATE" {
		b.Parts.Update.UpsertExp = convertUpsert(fields)
	} else {
		panic("DoUpdate is only available for UPDATE operation")
	}
	return b
}

func (b *Builder) DoNothing() *Builder {
	if b.Parts.Operation == "UPDATE" {
		b.Parts.Update.UpsertExp = "DO NOTHING"
	} else {
		panic("DoNothing is only available for UPDATE operation")
	}
	return b
}

func (b *Builder) Sql() (string, []interface{}) {
	operation := b.Parts.Operation
	switch {
	case operation == "SELECT" || operation == "SELECT DISTINCT":
		return unspace(strings.Join([]string{
			b.Parts.Operation,
			b.Parts.FieldsExp,
			b.Parts.From,
			b.Parts.FromExp,
			strings.Join(
				b.Parts.JoinExps,
				" ",
			),
			b.Parts.GroupExp,
			b.Parts.HavingExp,
			b.Parts.FiterExp,
			b.Parts.OrderExp,
			b.Parts.LimitExp,
			b.Parts.OffsetExp,
		}, " ")), nil
	case operation == "DELETE":
		return unspace(strings.Join([]string{
			b.Parts.Operation,
			b.Parts.From,
			b.Parts.FromExp,
			b.Parts.HavingExp,
			b.Parts.FiterExp,
			b.Parts.OrderExp,
			b.Parts.LimitExp,
			b.Parts.OffsetExp,
		}, " ")), nil
	case operation == "INSERT INTO":
		return b.Parts.Insert.Statement, b.Parts.Insert.Values
	case operation == "UPDATE":
		return unspace(strings.Join([]string{
			b.Parts.Update.Statement,
			b.Parts.Update.Upsert,
			b.Parts.Update.UpsertExp,
		}, " ")), b.Parts.Update.Values
	default:
		return "", nil
	}
}