package ass

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"

	"sub-cli/internal/model"
)

// 常量定义
const (
	ASSHeader = "[Script Info]"
	ASSStylesHeader = "[V4+ Styles]"
	ASSEventsHeader = "[Events]"
	DefaultFormat = "Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text"
)

// Parse 解析ASS文件为ASSFile结构
func Parse(filePath string) (model.ASSFile, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return model.ASSFile{}, fmt.Errorf("打开ASS文件失败: %w", err)
	}
	defer file.Close()

	result := model.NewASSFile()
	
	scanner := bufio.NewScanner(file)
	
	// 当前解析的区块
	currentSection := ""
	var styleFormat, eventFormat []string
	
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, ";") {
			// 跳过空行和注释行
			continue
		}
		
		// 检查章节标题
		if strings.HasPrefix(line, "[") && strings.HasSuffix(line, "]") {
			currentSection = line
			continue
		}
		
		switch currentSection {
		case ASSHeader:
			// 解析脚本信息
			if strings.Contains(line, ":") {
				parts := strings.SplitN(line, ":", 2)
				key := strings.TrimSpace(parts[0])
				value := strings.TrimSpace(parts[1])
				result.ScriptInfo[key] = value
			}
			
		case ASSStylesHeader:
			// 解析样式格式行和样式定义
			if strings.HasPrefix(line, "Format:") {
				formatStr := strings.TrimPrefix(line, "Format:")
				styleFormat = parseFormatLine(formatStr)
			} else if strings.HasPrefix(line, "Style:") {
				styleValues := parseStyleLine(line)
				if len(styleFormat) > 0 && len(styleValues) > 0 {
					style := model.ASSStyle{
						Name:       styleValues[0], // 第一个值通常是样式名称
						Properties: make(map[string]string),
					}
					
					// 将原始格式行保存下来
					style.Properties["Format"] = "Name, " + strings.Join(styleFormat[1:], ", ")
					style.Properties["Style"] = strings.Join(styleValues, ", ")
					
					// 解析各个样式属性
					for i := 0; i < len(styleFormat) && i < len(styleValues); i++ {
						style.Properties[styleFormat[i]] = styleValues[i]
					}
					
					result.Styles = append(result.Styles, style)
				}
			}
			
		case ASSEventsHeader:
			// 解析事件格式行和对话行
			if strings.HasPrefix(line, "Format:") {
				formatStr := strings.TrimPrefix(line, "Format:")
				eventFormat = parseFormatLine(formatStr)
			} else if len(eventFormat) > 0 && 
				(strings.HasPrefix(line, "Dialogue:") || 
				 strings.HasPrefix(line, "Comment:")) {
				
				eventType := "Dialogue"
				if strings.HasPrefix(line, "Comment:") {
					eventType = "Comment"
					line = strings.TrimPrefix(line, "Comment:")
				} else {
					line = strings.TrimPrefix(line, "Dialogue:")
				}
				
				values := parseEventLine(line)
				if len(values) >= len(eventFormat) {
					event := model.NewASSEvent()
					event.Type = eventType
					
					// 填充事件属性
					for i, format := range eventFormat {
						value := values[i]
						switch strings.TrimSpace(format) {
						case "Layer":
							layer, _ := strconv.Atoi(value)
							event.Layer = layer
						case "Start":
							event.StartTime = parseASSTimestamp(value)
						case "End":
							event.EndTime = parseASSTimestamp(value)
						case "Style":
							event.Style = value
						case "Name":
							event.Name = value
						case "MarginL":
							marginL, _ := strconv.Atoi(value)
							event.MarginL = marginL
						case "MarginR":
							marginR, _ := strconv.Atoi(value)
							event.MarginR = marginR
						case "MarginV":
							marginV, _ := strconv.Atoi(value)
							event.MarginV = marginV
						case "Effect":
							event.Effect = value
						case "Text":
							// 文本可能包含逗号，所以需要特殊处理
							textStartIndex := strings.Index(line, value)
							if textStartIndex >= 0 {
								event.Text = line[textStartIndex:]
							} else {
								event.Text = value
							}
						}
					}
					
					result.Events = append(result.Events, event)
				}
			}
		}
	}
	
	return result, nil
}