package platform

import (
	"bytes"
	"encoding/json"
	"io"
	"net/url"
	"regexp"
)

type Paragraph struct {
	ID          string `json:"id"`
	Text        string `json:"text"`
	Description string `json:"description,omitempty"`
}
type Section struct {
	ID          string      `json:"id"`
	Title       string      `json:"title"`
	Description string      `json:"description,omitempty"`
	Paragraphs  []Paragraph `json:"paragraphs"`
}
type Article struct {
	Sections []Section `json:"sections"`
}
type Image struct {
	URL    string `json:"url"`
	Alt    string `json:"alt,omitempty"`
	Width  int    `json:"width,omitempty"`
	Height int    `json:"height,omitempty"`
}
type CardPart struct {
	Kind    string   `json:"kind"`
	Text    *string  `json:"text,omitempty"`
	Article *Article `json:"article,omitempty"`
	Image   *Image   `json:"image,omitempty"`
}
type Content struct {
	SchemaVersion int        `json:"schema_version"`
	Text          *string    `json:"text,omitempty"`
	Article       *Article   `json:"article,omitempty"`
	Image         *Image     `json:"image,omitempty"`
	Parts         []CardPart `json:"parts,omitempty"`
}

var blockID = regexp.MustCompile(`^[A-Za-z0-9_-]{1,64}$`)

func validArticle(article *Article) bool {
	if article == nil || len(article.Sections) > 200 {
		return false
	}
	seen := map[string]bool{}
	total := 0
	for _, section := range article.Sections {
		if !blockID.MatchString(section.ID) || seen[section.ID] || len(section.Title) > 300 || len(section.Description) > 10000 {
			return false
		}
		seen[section.ID] = true
		total += len(section.Paragraphs)
		if total > 2000 {
			return false
		}
		for _, paragraph := range section.Paragraphs {
			if !blockID.MatchString(paragraph.ID) || seen[paragraph.ID] || len(paragraph.Text) > 100000 || len(paragraph.Description) > 10000 {
				return false
			}
			seen[paragraph.ID] = true
		}
	}
	return true
}
func validImage(image *Image) bool {
	if image == nil || len(image.URL) > 2048 || len(image.Alt) > 2000 || image.Width < 0 || image.Width > 100000 || image.Height < 0 || image.Height > 100000 {
		return false
	}
	u, err := url.Parse(image.URL)
	return err == nil && u.Scheme == "https" && u.Hostname() != "" && u.User == nil && u.Fragment == ""
}
func validPart(part CardPart) bool {
	switch part.Kind {
	case "text":
		return part.Text != nil && len(*part.Text) <= 100000 && part.Article == nil && part.Image == nil
	case "article":
		return part.Text == nil && part.Image == nil && validArticle(part.Article)
	case "image":
		return part.Text == nil && part.Article == nil && validImage(part.Image)
	default:
		return false
	}
}
func normalizeContent(kind string, raw json.RawMessage) (json.RawMessage, bool) {
	if raw = bytes.TrimSpace(raw); len(raw) == 0 || raw[0] != '{' {
		return nil, false
	}
	var content Content
	d := json.NewDecoder(bytes.NewReader(raw))
	d.DisallowUnknownFields()
	if d.Decode(&content) != nil || d.Decode(new(any)) != io.EOF {
		return nil, false
	}
	if content.SchemaVersion == 0 {
		content.SchemaVersion = 1
	}
	if content.SchemaVersion != 1 {
		return nil, false
	}
	switch kind {
	case "text", "article", "image":
		if len(content.Parts) > 0 || !validPart(CardPart{Kind: kind, Text: content.Text, Article: content.Article, Image: content.Image}) {
			return nil, false
		}
	case "board":
		if content.Text != nil || content.Article != nil || content.Image != nil || len(content.Parts) > 0 {
			return nil, false
		}
	case "card":
		if content.Text != nil || content.Article != nil || content.Image != nil || len(content.Parts) < 1 || len(content.Parts) > 20 {
			return nil, false
		}
		for _, part := range content.Parts {
			if !validPart(part) {
				return nil, false
			}
		}
	default:
		return nil, false
	}
	out, err := json.Marshal(content)
	return out, err == nil
}