package schema

import (
	"encoding/json"
	"fmt"
)

type Table struct {
	Name   string  `json:"table"`
	Schema []Field `json:"schema"`
}

type Field struct {
	Name       string     `json:"name"`
	Type       string     `json:"type"`
	Nullable   *bool      `json:"nullable"`
	Default    *string    `json:"default"`
	Unique     *bool      `json:"unique"`
	Primary    *bool      `json:"primary"`
	Comment    *string    `json:"comment"`
	References *Reference `json:"references"`
	Algorithm  *string    `json:"algorithm"`
}

type Reference struct {
	Table    string `json:"table"`
	Column   string `json:"column"`
	OnDelete string `json:"onDelete"`
	OnUpdate string `json:"onUpdate"`
}

// Mapping of field types to SQL types
var fieldTypeToSQLType = map[string]string{
	"string":   "VARCHAR",
	"int":      "INTEGER",
	"float":    "FLOAT",
	"bool":     "BOOLEAN",
	"date":     "DATE",
	"time":     "TIME",
	"datetime": "TIMESTAMP",
	"uuid":     "UUID",
	"json":     "JSONB",
	"hash":     "VARCHAR",
}

func NewTable(data []byte) (*Table, error) {
	var table Table
	err := json.Unmarshal(data, &table)
	if err != nil {
		return nil, err
	}
	return &table, nil
}

func (t *Table) JSON() ([]byte, error) {
	return json.Marshal(t)
}

func (f *Field) SQL() string {
	sqlType := fieldTypeToSQLType[f.Type]
	if sqlType == "" {
		return ""
	}
	sql := fmt.Sprintf("%s %s", f.Name, sqlType)
	if f.Nullable != nil && !*f.Nullable {
		sql += " NOT NULL"
	}
	if f.Primary != nil && *f.Primary {
		sql += " PRIMARY KEY"
		if f.Default == nil && f.Type == "uuid" {
			sql += " DEFAULT uuid_generate_v4()"
		}
	}
	if f.Unique != nil && *f.Unique {
		sql += " UNIQUE"
	}
	if f.Default != nil && f.Primary == nil {
		sql += fmt.Sprintf(" DEFAULT %s", *f.Default)
	}
	if f.References != nil {
		sql += fmt.Sprintf(" REFERENCES %s(%s)", f.References.Table, f.References.Column)
		if f.References.OnDelete != "" {
			sql += fmt.Sprintf(" ON DELETE %s", f.References.OnDelete)
		}
		if f.References.OnUpdate != "" {
			sql += fmt.Sprintf(" ON UPDATE %s", f.References.OnUpdate)
		}
	}
	return sql
}

func (f *Field) SQLReferences() string {
	if f.References == nil {
		return ""
	}
	return fmt.Sprintf(" REFERENCES %s(%s)", f.References.Table, f.References.Column)
}