package flow

import (
	"ai-agent/gateway"
	"context"
	"encoding/base64"
	"fmt"
	"strings"

	"gitea.redpowerfuture.com/red-future/common/oss"
	"github.com/gogf/gf/v2/util/gconv"
	"github.com/google/uuid"
)

// resolveSaveFileResult 解析结果值为可入库的 URL：
//   - 已是 http(s) URL 或 MinIO 对象裸路径 → 直接返回
//   - 非路径（base64 图片/文本）→ 上传 OSS 换取 URL
func resolveSaveFileResult(ctx context.Context, val any) (string, error) {
	isPath, path, fileBytes, ext := resolveFileContent(val)
	if isPath {
		return path, nil
	}
	if ext == "" {
		ext = ".png"
	}
	fileUrl, err := gateway.Upload(ctx, fmt.Sprintf("workflow_result_%s%s", uuid.NewString(), ext), fileBytes)
	if err != nil {
		return "", err
	}
	return fileUrl, nil
}

// resolveFileContent 判断结果值形态：
//   - 已是 URL 路径（http/https 开头）→ 直接使用
//   - data URI（data:<mime>;base64,<data>）→ 解码为字节，扩展名按 mime 推断
//   - 纯 base64（可解码且长度足以认为是编码数据）→ 解码为字节，默认 .png
//   - 其余（文本）→ 以 .inc 扩展名上传原文
func resolveFileContent(val any) (isPath bool, path string, fileBytes []byte, ext string) {
	s := gconv.String(val)
	if isFileURL(s) {
		return true, s, nil, ""
	}
	// MinIO 对象裸路径（无 http 前缀，模型网关转存 OSS 后返回）
	if oss.IsOSSPath(s) {
		return true, s, nil, ""
	}
	// data URI：data:<mime>;base64,<payload>
	if b, mime, ok := parseDataURI(s); ok {
		return false, "", b, extOfMime(mime)
	}
	// 纯 base64：可解码且长度足够，视为编码后的文件内容
	trimmed := strings.TrimSpace(s)
	if len(trimmed) >= 64 {
		if b, err := base64.StdEncoding.DecodeString(trimmed); err == nil && len(b) > 0 {
			return false, "", b, ".png"
		}
	}
	// 文本：以 .inc 存储
	return false, "", []byte(s), ".inc"
}

// isFileURL 判断字符串是否已是对外可访问的 URL 路径（http/https 开头）
func isFileURL(s string) bool {
	lower := strings.ToLower(s)
	return strings.HasPrefix(lower, "http://") || strings.HasPrefix(lower, "https://")
}

// extOfMime 按 MIME 类型推断文件扩展名
func extOfMime(mime string) string {
	switch strings.ToLower(strings.TrimSpace(mime)) {
	case "image/png", "png":
		return ".png"
	case "image/jpeg", "image/jpg", "jpeg", "jpg":
		return ".jpg"
	case "image/webp":
		return ".webp"
	case "image/gif":
		return ".gif"
	case "audio/mpeg", "audio/mp3", "mp3":
		return ".mp3"
	case "audio/wav", "wav":
		return ".wav"
	case "video/mp4", "mp4":
		return ".mp4"
	case "application/json", "json":
		return ".json"
	default:
		return ""
	}
}

// parseDataURI 解析 data URI：data:<mime>;base64,<payload>，返回解码字节与 mime
func parseDataURI(s string) ([]byte, string, bool) {
	const prefix = "data:"
	if !strings.HasPrefix(s, prefix) {
		return nil, "", false
	}
	rest := s[len(prefix):]
	comma := strings.Index(rest, ",")
	if comma < 0 {
		return nil, "", false
	}
	mime := rest[:comma]
	if semicolon := strings.Index(mime, ";"); semicolon >= 0 {
		mime = mime[:semicolon]
	}
	payload := strings.TrimPrefix(rest[comma+1:], "base64,")
	b, err := base64.StdEncoding.DecodeString(payload)
	if err != nil {
		return nil, "", false
	}
	return b, mime, true
}