package utils

import (
	"regexp"
	"strings"
)

// BBCodeToMarkdown converts simplified Siropu-style BBCode into Matrix-safe Markdown.
//
// RULES:
//   - [img]URL[/img] remains an image but without video tagging
//   - [url] and [url=...] become markdown links
//   - All [video]...[/video] wrappers are REMOVED entirely (your requirement)
//   - Bold/italic/underline basic BBCode converted to markdown
//   - Unknown tags stripped and inner text preserved
//
func BBCodeToMarkdown(in string) string {
	if in == "" {
		return ""
	}
	s := in

	// ----------------------------------------------------
	// STRIP VIDEO TAGS COMPLETELY
	// ----------------------------------------------------
	s = stripTagCompletely(s, "video")

	// ----------------------------------------------------
	// IMAGE TAGS → leave as-is, but sanitize formatting
	// ----------------------------------------------------
	s = regexp.MustCompile(`(?i)\[img\](.*?)\[/img\]`).ReplaceAllString(s, "![]($1)")

	// ----------------------------------------------------
	// URL TAGS → Markdown links
	// ----------------------------------------------------
	// [url]http://x[/url]
	s = regexp.MustCompile(`(?i)\[url\](.*?)\[/url\]`).ReplaceAllString(s, "[$1]($1)")

	// [url=http://x]label[/url]
	s = regexp.MustCompile(`(?i)\[url=(.*?)\](.*?)\[/url\]`).ReplaceAllString(s, "[$2]($1)")

	// ----------------------------------------------------
	// BASIC FORMATTING → Markdown
	// ----------------------------------------------------
	replacements := map[*regexp.Regexp]string{
		regexp.MustCompile(`(?i)\[b\](.*?)\[/b\]`):     "**$1**",
		regexp.MustCompile(`(?i)\[i\](.*?)\[/i\]`):     "*$1*",
		regexp.MustCompile(`(?i)\[u\](.*?)\[/u\]`):     "__$1__",
		regexp.MustCompile(`(?i)\[s\](.*?)\[/s\]`):     "~~$1~~",
		regexp.MustCompile(`(?i)\[quote\](.*?)\[/quote\]`): "> $1",
	}

	for re, repl := range replacements {
		s = re.ReplaceAllString(s, repl)
	}

	// ----------------------------------------------------
	// REMOVE ANY OTHER BBCODE TAGS, KEEP CONTENT
	// ----------------------------------------------------
	s = regexp.MustCompile(`(?i)\[(\/?)[a-zA-Z0-9\=\#]+?\]`).ReplaceAllString(s, "")

	// Cleanup whitespace
	return strings.TrimSpace(s)
}

// stripTagCompletely removes [tag]...[/tag] entirely, preserving inner text only if desired.
// Here we drop everything inside video tags.
func stripTagCompletely(s, tag string) string {
	re := regexp.MustCompile(`(?is)\[` + tag + `(?:=[^\]]*)?\].*?\[\/` + tag + `\]`)
	return re.ReplaceAllString(s, "")
}
// IsImageURL determines whether a string looks like an image link.
// Used by both Matrix → Sneed and Sneed → Matrix paths.
func IsImageURL(u string) bool {
	u = strings.ToLower(strings.TrimSpace(u))
	if !(strings.HasPrefix(u, "http://") || strings.HasPrefix(u, "https://")) {
		return false
	}

	// strip query
	if i := strings.Index(u, "?"); i > 0 {
		u = u[:i]
	}

	return strings.HasSuffix(u, ".png") ||
		strings.HasSuffix(u, ".jpg") ||
		strings.HasSuffix(u, ".jpeg") ||
		strings.HasSuffix(u, ".gif") ||
		strings.HasSuffix(u, ".webp")
}

// WrapImageForSneed produces the BBCode wrapper used for outbound
// Matrix → Sneed image messages.
//
// Example:
//   input:  "https://example.com/img.jpg"
//   output: "[url=https://example.com/img.jpg][img]https://example.com/img.jpg[/img][/url]"
//
func WrapImageForSneed(url string) string {
	if url == "" {
		return ""
	}
	return "[url=" + url + "][img]" + url + "[/img][/url]"
}

// ExtractFirstURL finds the first URL-like token in a message.
// Useful for deciding if a message is an image-only post.
func ExtractFirstURL(s string) string {
	re := regexp.MustCompile(`https?://[^\s]+`)
	found := re.FindString(s)
	return found
}