package rss

import (
	"encoding/xml"
	"fmt"
)

type Image struct {
	XMLName xml.Name `xml:"image"`
	Url     string   `xml:"url"`
	Title   string   `xml:"title"`
	Link    string   `xml:"link"`
	Width   int      `xml:"width,omitempty"`  // max: 144, default: 88
	Height  int      `xml:"height,omitempty"` // max: 400, default: 31
}

type TextInput struct {
	XMLName     xml.Name `xml:"textInput"`
	Title       string   `xml:"title,omitempty"`
	Description string   `xml:"description,omitempty"`
	Name        string   `xml:"name,omitempty"`
	Link        string   `xml:"link,omitempty"`
}

type Enclosure struct {
	XMLName xml.Name `xml:"enclosure"`
	Url     string   `xml:"url,attr"`
	Type    string   `xml:"type,attr"`
	Lenght  int      `xml:"lenght,attr"`
}

type Source struct {
	XMLName xml.Name `xml:"source"`
	Url     string   `xml:"url,attr"`
	Value   string
}

func (i *Image) check() error {
	if len(i.Url) == 0 {
		return fmt.Errorf("error: url not set")
	}
	if len(i.Title) == 0 {
		return fmt.Errorf("error: title not set")
	}
	if len(i.Link) == 0 {
		return fmt.Errorf("error: link not set")
	}
	if i.Width == 0 || i.Width > 144 {
		i.Width = 88
	}
	if i.Height == 0 || i.Height > 400 {
		i.Height = 31
	}

	return nil
}

func (t *TextInput) check() error {
	if len(t.Title) == 0 &&
		len(t.Description) == 0 &&
		len(t.Name) == 0 &&
		len(t.Link) == 0 {
		return fmt.Errorf("error: textInput is empty")
	}

	return nil
}

func (e *Enclosure) check() error {
	if len(e.Url) == 0 {
		return fmt.Errorf("error: url not set")
	}
	if e.Lenght == 0 {
		return fmt.Errorf("error: length not set or 0")
	}
	if len(e.Type) == 0 {
		return fmt.Errorf("error: type not set")
	}

	return nil
}

func (s *Source) check() error {
	if len(s.Url) == 0 {
		return fmt.Errorf("error: url not set")
	}
	if len(s.Value) == 0 {
		return fmt.Errorf("error: value not set")
	}

	return nil
}

func (f *Feed) ToXML() (string, error) {
	if err := f.check(); err != nil {
		return "", fmt.Errorf("error checking RSS feed: %v", err)
	}

	xml, err := xml.MarshalIndent(f, "", "  ")
	if err != nil {
		return "", fmt.Errorf("error XML encoding feed: %v", err)
	}

	return string(xml), nil
}