package subscription

import (
	"strings"

	"gopkg.in/yaml.v3"

	"gitea.epss.net.cn/klesh/ss/internal/yamlutil"
)

// convertContent converts subscription content to Clash YAML format if
// needed. Direct port of SubscriptionManager._convert_content.
func convertContent(content string) string {
	// Check if content is already valid YAML with a "proxies" key.
	var parsed map[string]interface{}
	if err := yamlutil.Unmarshal([]byte(content), &parsed); err == nil {
		if _, ok := parsed["proxies"]; ok {
			return content
		}
	}

	var lines []string

	// Try treating as Base64-encoded list first.
	if !strings.Contains(content, "ss://") &&
		!strings.Contains(content, "trojan://") &&
		!strings.Contains(content, "vless://") {
		if decoded, err := base64StdDecodeWithPadding(content); err == nil {
			lines = splitLines(decoded)
		}
	}

	// Fallback to reading lines directly.
	if len(lines) == 0 {
		lines = splitLines(content)
	}

	var proxies []map[string]interface{}
	for _, line := range lines {
		line = strings.TrimSpace(line)
		if line == "" {
			continue
		}

		var proxy map[string]interface{}
		switch {
		case strings.HasPrefix(line, "ss://"):
			proxy = parseSS(line)
		case strings.HasPrefix(line, "trojan://"):
			proxy = parseTrojan(line)
		case strings.HasPrefix(line, "vless://"):
			proxy = parseVless(line)
		}

		if proxy != nil {
			proxies = append(proxies, proxy)
		}
	}

	if len(proxies) > 0 {
		out, err := yaml.Marshal(map[string]interface{}{"proxies": proxies})
		if err == nil {
			return string(out)
		}
	}

	return content
}

// splitLines mirrors Python's str.splitlines(): split on \n, \r\n, and \r,
// without keeping the line endings, and without producing a trailing empty
// element for a final newline.
func splitLines(s string) []string {
	s = strings.ReplaceAll(s, "\r\n", "\n")
	s = strings.ReplaceAll(s, "\r", "\n")
	s = strings.TrimSuffix(s, "\n")
	if s == "" {
		return nil
	}
	return strings.Split(s, "\n")
}