package casbinauthz

import (
	"errors"

	"github.com/casbin/casbin/model"
	"github.com/casbin/casbin/persist"
	"github.com/jinzhu/gorm"
	"github.com/revel/modules/orm/gorm/app"
)

type Line struct {
	PType string `gorm:"size:100"`
	V0    string `gorm:"size:100"`
	V1    string `gorm:"size:100"`
	V2    string `gorm:"size:100"`
	V3    string `gorm:"size:100"`
	V4    string `gorm:"size:100"`
	V5    string `gorm:"size:100"`
}

// Adapter represents the Gorm adapter for policy storage.
type Adapter struct {
	driverName     string
	dataSourceName string
	db             *gorm.DB
}

// NewAdapter is the constructor for Adapter.
func NewAdapter(params gormdb.DbInfo) *Adapter {
	a := &Adapter{}
	gormdb.InitDBWithParameters(params)
	a.db = gormdb.DB

	return a
}

func (a *Adapter) createTable() {
	if a.db.HasTable(&Line{}) {
		return
	}

	err := a.db.CreateTable(&Line{}).Error
	if err != nil {
		panic(err)
	}
}

func (a *Adapter) dropTable() {
	err := a.db.DropTable(&Line{}).Error
	if err != nil {
		panic(err)
	}
}

func loadPolicyLine(line Line, model model.Model) {
	lineText := line.PType
	if line.V0 != "" {
		lineText += ", " + line.V0
	}
	if line.V1 != "" {
		lineText += ", " + line.V1
	}
	if line.V2 != "" {
		lineText += ", " + line.V2
	}
	if line.V3 != "" {
		lineText += ", " + line.V3
	}
	if line.V4 != "" {
		lineText += ", " + line.V4
	}
	if line.V5 != "" {
		lineText += ", " + line.V5
	}

	persist.LoadPolicyLine(lineText, model)
}

// LoadPolicy loads policy from database.
func (a *Adapter) LoadPolicy(model model.Model) error {
	var lines []Line
	err := a.db.Find(&lines).Error
	if err != nil {
		return err
	}

	for _, line := range lines {
		loadPolicyLine(line, model)
	}

	return nil
}

func savePolicyLine(ptype string, rule []string) Line {
	line := Line{}

	line.PType = ptype
	if len(rule) > 0 {
		line.V0 = rule[0]
	}
	if len(rule) > 1 {
		line.V1 = rule[1]
	}
	if len(rule) > 2 {
		line.V2 = rule[2]
	}
	if len(rule) > 3 {
		line.V3 = rule[3]
	}
	if len(rule) > 4 {
		line.V4 = rule[4]
	}
	if len(rule) > 5 {
		line.V5 = rule[5]
	}

	return line
}

// SavePolicy saves policy to database.
func (a *Adapter) SavePolicy(model model.Model) error {
	a.dropTable()
	a.createTable()

	for ptype, ast := range model["p"] {
		for _, rule := range ast.Policy {
			line := savePolicyLine(ptype, rule)
			err := a.db.Create(&line).Error
			if err != nil {
				return err
			}
		}
	}

	for ptype, ast := range model["g"] {
		for _, rule := range ast.Policy {
			line := savePolicyLine(ptype, rule)
			err := a.db.Create(&line).Error
			if err != nil {
				return err
			}
		}
	}

	return nil
}

// AddPolicy adds a policy rule to the storage.
func (a *Adapter) AddPolicy(sec string, ptype string, rule []string) error {
	return errors.New("not implemented")
}

// RemovePolicy removes a policy rule from the storage.
func (a *Adapter) RemovePolicy(sec string, ptype string, rule []string) error {
	return errors.New("not implemented")
}

// RemoveFilteredPolicy removes policy rules that match the filter from the storage.
func (a *Adapter) RemoveFilteredPolicy(sec string, ptype string, fieldIndex int, fieldValues ...string) error {
	return errors.New("not implemented")
}