package faultRecordFile

import (
	"fmt"

	proto "fwh-toolbox-server/function/FaultRecordProtocol"
)

// Overview code=1 故障总体信息
type Overview struct {
	MaxRecords     uint8  `json:"maxRecords"`
	CurrentRecords uint8  `json:"currentRecords"`
	EarliestTime   string `json:"earliestTime"` // 设备时间
	LatestTime     string `json:"latestTime"`
	ChannelGroups
}

// DirectoryEntry code=3 目录项（14 字节）
type DirectoryEntry struct {
	Index             uint8  `json:"index"`
	Time              string `json:"time"` // 设备时间
	ParamListVersion  string `json:"paramListVersion"`
	TriggerSource     uint16 `json:"triggerSource"`
	TriggerSourceName string `json:"triggerSourceName,omitempty"`
}

const directoryEntrySize = 14

// ParseOverview 解析 code=1
func ParseOverview(b []byte) (Overview, error) {
	r := &byteReader{b: b}
	o := Overview{
		MaxRecords:     r.u8("maxRecords"),
		CurrentRecords: r.u8("currentRecords"),
		EarliestTime:   r.time("earliestTime").String(),
		LatestTime:     r.time("latestTime").String(),
	}
	o.ChannelGroups = readChannelGroups(r, false)
	return o, r.err
}

// ParseBasicInfo 解析 code=2
func ParseBasicInfo(b []byte) (BasicInfo, error) {
	if len(b) != 16 {
		return BasicInfo{}, fmt.Errorf("basic info must be 16 bytes, got %d", len(b))
	}
	r := &byteReader{b: b}
	return readBasicInfo(r), r.err
}

// ParseDirectory 解析 code=3：1 字节条数 + N × 14 字节
func ParseDirectory(b []byte) ([]DirectoryEntry, error) {
	if len(b) < 1 {
		return nil, fmt.Errorf("directory is empty")
	}
	n := int(b[0])
	if len(b) != 1+n*directoryEntrySize {
		return nil, fmt.Errorf("directory length %d does not match %d entries", len(b), n)
	}
	r := &byteReader{b: b[1:]}
	list := make([]DirectoryEntry, 0, n)
	for i := 0; i < n; i++ {
		e := DirectoryEntry{
			Index:            r.u8("index"),
			Time:             r.time("time").String(),
			ParamListVersion: fmt.Sprintf("%08X", r.u32("paramListVersion")),
			TriggerSource:    r.u16("triggerSource"),
		}
		e.TriggerSourceName = proto.TriggerSourceName(e.TriggerSource)
		list = append(list, e)
	}
	return list, r.err
}

// ParseRealtime 按 code 解析 hexData，返回对应结构
func ParseRealtime(code int, hexData string) (any, error) {
	b, err := proto.DecodeHex(hexData)
	if err != nil {
		return nil, err
	}
	switch code {
	case 1:
		return ParseOverview(b)
	case 2:
		return ParseBasicInfo(b)
	case 3:
		return ParseDirectory(b)
	default:
		return nil, fmt.Errorf("unsupported code %d", code)
	}
}