package models

import (
	"bytes"
	"encoding/json"
	"net/mail"
	"net/url"
	"path"
	"text/template"
)

// TemplateContext is an interface that allows both campaigns and email
// requests to have a PhishingTemplateContext generated for them.
type TemplateContext interface {
	getFromAddress() string
	getBaseURL() string
}

// PhishingTemplateContext is the context that is sent to any template, such
// as the email or landing page content.
type PhishingTemplateContext struct {
	From        string
	URL         string
	Tracker     string
	TrackingURL string
	RId         string
	BaseURL     string
	BaseRecipient
}

// NewPhishingTemplateContext returns a populated PhishingTemplateContext,
// parsing the correct fields from the provided TemplateContext and recipient.
func NewPhishingTemplateContext(ctx TemplateContext, r BaseRecipient, rid string) (PhishingTemplateContext, error) {
	f, err := mail.ParseAddress(ctx.getFromAddress())
	if err != nil {
		return PhishingTemplateContext{}, err
	}
	fn := f.Name
	if fn == "" {
		fn = f.Address
	}
	templateURL, err := ExecuteTemplate(ctx.getBaseURL(), r)
	if err != nil {
		return PhishingTemplateContext{}, err
	}

	// For the base URL, we'll reset the the path and the query
	// This will create a URL in the form of http://example.com
	baseURL, err := url.Parse(templateURL)
	if err != nil {
		return PhishingTemplateContext{}, err
	}
	baseURL.Path = ""
	baseURL.RawQuery = ""

	phishURL, _ := url.Parse(templateURL)
	q := phishURL.Query()
	q.Set(RecipientParameter, rid)
	phishURL.RawQuery = q.Encode()

	trackingURL, _ := url.Parse(templateURL)
	trackingURL.Path = path.Join(trackingURL.Path, "/track")
	trackingURL.RawQuery = q.Encode()

	return PhishingTemplateContext{
		BaseRecipient: r,
		BaseURL:       baseURL.String(),
		URL:           phishURL.String(),
		TrackingURL:   trackingURL.String(),
		Tracker:       "<img alt='' style='display: none' src='" + trackingURL.String() + "'/>",
		From:          fn,
		RId:           rid,
	}, nil
}

// ExecuteTemplate creates a templated string based on the provided
// template body and data.
func ExecuteTemplate(text string, data interface{}) (string, error) {
	buff := bytes.Buffer{}
	// replacing template params with no corresponding map keys with empty string.
	tmpl, err := template.New("template").Option("missingkey=zero").Parse(text)
	if err != nil {
		return buff.String(), err
	}
	err = tmpl.Execute(&buff, data)
	return buff.String(), err
}

// ValidationContext is used for validating templates and pages
type ValidationContext struct {
	FromAddress string
	BaseURL     string
}

func (vc ValidationContext) getFromAddress() string {
	return vc.FromAddress
}

func (vc ValidationContext) getBaseURL() string {
	return vc.BaseURL
}

// ValidateTemplate ensures that the provided text in the page or template
// uses the supported template variables correctly.
func ValidateTemplate(text string) error {
	vc := ValidationContext{
		FromAddress: "foo@bar.com",
		BaseURL:     "http://example.com",
	}
	td := Result{
		BaseRecipient: BaseRecipient{
			Email:     "foo@bar.com",
			FirstName: "Foo",
			LastName:  "Bar",
			Position:  "Test",
		},
		RId: "123456",
	}
	ptx, err := NewPhishingTemplateContext(vc, td.BaseRecipient, td.RId)
	if err != nil {
		return err
	}
	_, err = ExecuteTemplate(text, ptx)
	if err != nil {
		return err
	}
	return nil
}

// GetAllTemplateParams merges the PhishingTemplateContext with the extended_parameters
// if extended_parameters are valid JSON
func GetAllTemplateParams(ptx PhishingTemplateContext) map[string]string {
	currentTemplateParams := map[string]string{
		"From":        ptx.From,
		"URL":         ptx.URL,
		"Tracker":     ptx.Tracker,
		"TrackingURL": ptx.TrackingURL,
		"RId":         ptx.RId,
		"BaseURL":     ptx.BaseURL,
		"Email":       ptx.BaseRecipient.Email,
		"FirstName":   ptx.BaseRecipient.FirstName,
		"LastName":    ptx.BaseRecipient.LastName,
		"Position":    ptx.BaseRecipient.Position,
	}
	extendedTemplateParams := map[string]string{}
	err := json.Unmarshal([]byte(ptx.BaseRecipient.ExtendedTemplate), &extendedTemplateParams)

	if err == nil {
		// only merge if we have a valid JSON in extended_parameters
		for k, v := range extendedTemplateParams {
			currentTemplateParams[k] = v
		}
	}
	return currentTemplateParams

}