package handler

import (
	"encoding/json"
	"html"
	"regexp"
	"strings"
	"unicode/utf8"

	"soul-api/internal/model"

	"gorm.io/gorm"
)

var (
	reHTMLScript = regexp.MustCompile(`(?is)<script[^>]*>.*?</script>`)
	reHTMLStyle  = regexp.MustCompile(`(?is)<style[^>]*>.*?</style>`)
	reHTMLBr     = regexp.MustCompile(`(?i)<\s*br\s*/?>`)
	reHTMLPClose = regexp.MustCompile(`(?i)</\s*p\s*>`)
	reHTMLTags   = regexp.MustCompile(`<[^>]+>`)
)

// stripHTMLToPlainPreview 将正文 HTML 转为纯文本再截取，避免预览截在 <img 中间导致用户看到半截标签
func stripHTMLToPlainPreview(s string) string {
	s = reHTMLScript.ReplaceAllString(s, " ")
	s = reHTMLStyle.ReplaceAllString(s, " ")
	s = reHTMLBr.ReplaceAllString(s, "\n")
	s = reHTMLPClose.ReplaceAllString(s, "\n")
	s = reHTMLTags.ReplaceAllString(s, "")
	s = html.UnescapeString(s)
	s = strings.NewReplacer("\r\n", "\n", "\r", "\n").Replace(s)
	return strings.TrimSpace(s)
}

// chapterPreviewPercent 章节单独 preview_percent 覆盖全局 unpaid_preview_percent
func chapterPreviewPercent(db *gorm.DB, ch *model.Chapter) int {
	g := getUnpaidPreviewPercent(db)
	if ch != nil && ch.PreviewPercent != nil {
		p := *ch.PreviewPercent
		if p >= 1 && p <= 100 {
			return p
		}
	}
	return g
}

// previewContent 取内容的前 percent%（按纯文本 rune 计；原 HTML 先剥标签）——用于 H5 落地页等；小程序读章节接口应返回全文并由端上按渲染高度裁切。
func previewContent(content string, percent int) string {
	work := content
	if strings.Contains(content, "<") && strings.Contains(content, ">") {
		work = stripHTMLToPlainPreview(content)
	}
	total := utf8.RuneCountInString(work)
	if total == 0 {
		return ""
	}
	if percent < 1 {
		percent = 1
	}
	if percent > 100 {
		percent = 100
	}
	limit := total * percent / 100
	if limit < 100 {
		limit = 100
	}
	const maxPreview = 500
	if limit > maxPreview {
		limit = maxPreview
	}
	if limit > total {
		limit = total
	}
	runes := []rune(work)
	return string(runes[:limit]) + "\n\n……"
}

func defaultReadPreviewUI() map[string]string {
	return map[string]string{
		"singlePageUnlockTitle":   "解锁全文",
		"singlePagePayButtonText": "支付 ¥{price} 解锁全文",
		"singlePageExpandedHint":  "预览页不能直接付款，务必先点底栏「前往小程序」。",
		"payTapModalTitle":        "解锁说明",
		"payTapModalContent":      "全文 ¥{price}。预览里无法完成支付：请先点屏幕底部「前往小程序」进入完整版，登录后再付款解锁。",
		"fullUnlockTitle":         "",
		"fullUnlockDesc":          "",
		"fullLockedProgressText":  "",
		"fullPaywallTip":          "转发给需要的人，一起学习还能赚佣金",
		"notLoginUnlockDesc":      "",
		"notLoginPaywallTip":      "转发给需要的人，一起学习还能赚佣金",
		"shareTipLine":            "转发给需要的人，一起学习还能赚佣金",
		"momentsModalTitle":       "分享到朋友圈",
		"momentsModalContent":     "已复制发圈文案（非分享给好友）。\n\n请点击右上角「···」→「分享到朋友圈」粘贴发布。",
		"momentsClipboardFooter":    "\n\n—— 以上为正文预览约 {percent}% ，搜「卡若创业派对」小程序阅读全文 ——",
		"timelineImageUrl":       "",
	}
}

// mergeReadPreviewUI 合并 system_config.read_preview_ui（JSON 对象）与默认文案；占位符 {percent}/{price} 由小程序替换
func mergeReadPreviewUI(db *gorm.DB) map[string]string {
	out := defaultReadPreviewUI()
	var row model.SystemConfig
	if err := db.Where("config_key = ?", "read_preview_ui").First(&row).Error; err != nil || len(row.ConfigValue) == 0 {
		return out
	}
	var raw map[string]interface{}
	if err := json.Unmarshal(row.ConfigValue, &raw); err != nil {
		return out
	}
	for k, v := range raw {
		switch t := v.(type) {
		case string:
			if strings.TrimSpace(t) != "" {
				out[k] = strings.TrimSpace(t)
			}
		default:
			// 兼容数字等被误存：忽略非字符串
		}
	}
	return out
}