package faultRecordFile

import (
	"encoding/binary"
	"fmt"

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

const versionFieldSize = 64

// FailureData failuredata（code=4 单一故障信息）
type FailureData struct {
	DeclaredLength    uint16    `json:"declaredLength"` // 样本中等于整个文件字节数（含填充），不作为有效长度使用
	Basic             BasicInfo `json:"basic"`
	Index             uint8     `json:"index"`
	Time              string    `json:"time"` // 设备时间
	TriggerSource     uint16    `json:"triggerSource"`
	TriggerSourceName string    `json:"triggerSourceName,omitempty"`
	DcdcVersion       string    `json:"dcdcVersion"`
	InvVersion        string    `json:"invVersion,omitempty"`  // aGate 中为填充，不解析
	FpgaVersion       string    `json:"fpgaVersion,omitempty"` // aGate 中为填充，不解析
	ChannelGroups
	ParsedBytes int `json:"parsedBytes"` // 结构结束位置，之后为填充
}

// ParseFailureData 按结构逐项解析，结构结束后的内容（0xFF 填充）忽略
func ParseFailureData(b []byte, deviceType string) (FailureData, error) {
	r := &byteReader{b: b}
	f := FailureData{
		DeclaredLength: r.u16("length"),
		Basic:          readBasicInfo(r),
		Index:          r.u8("index"),
		Time:           r.time("time").String(),
		TriggerSource:  r.u16("triggerSource"),
	}
	f.TriggerSourceName = proto.TriggerSourceName(f.TriggerSource)
	f.DcdcVersion = cString(r.take(versionFieldSize, "dcdcVersion"))
	inv := r.take(versionFieldSize, "invVersion")
	fpga := r.take(versionFieldSize, "fpgaVersion")
	if deviceType != proto.DeviceTypeAGate {
		f.InvVersion = cString(inv)
		f.FpgaVersion = cString(fpga)
	}
	f.ChannelGroups = readChannelGroups(r, true)
	f.ParsedBytes = r.p
	return f, r.err
}

// WaveformChannel 一个采样通道的全部点（原始 int16 值）
type WaveformChannel struct {
	Number  int    `json:"number"`  // 通道序号，从 0 开始
	Meaning uint16 `json:"meaning"` // 采样通道含义（可配通道处为类型码）
	// Configurable 采样通道列表末尾的通道对应可配采样通道（按样本推断）
	Configurable *ConfigurableChannel `json:"configurable,omitempty"`
	Values       []int16              `json:"values"`
}

// Waveform waveformdata（code=5 单一故障波形数据）
type Waveform struct {
	Points          int               `json:"points"`
	PrePoints       int               `json:"prePoints"`
	SampleFrequency int               `json:"sampleFrequency"`
	Channels        []WaveformChannel `json:"channels"`
}

// ParseWaveform 采样点优先排列：先排第 1 点的 n 个通道，再排第 2 点，依此类推。
// 通道数取 failuredata 的“采样通道总数”，点数取基本信息的“采样点总数”；每点每通道 2 字节、大端、按 int16 解释。
func ParseWaveform(b []byte, fd FailureData) (Waveform, error) {
	n := int(fd.SampleTotal)
	m := int(fd.Basic.TotalPoints)
	if n == 0 || m == 0 {
		return Waveform{}, fmt.Errorf("invalid waveform shape: %d channels × %d points", n, m)
	}
	if len(b) != n*m*2 {
		return Waveform{}, fmt.Errorf("waveform length %d does not match %d channels × %d points × 2", len(b), n, m)
	}

	w := Waveform{
		Points:          m,
		PrePoints:       int(fd.Basic.PrePoints),
		SampleFrequency: int(fd.Basic.SampleFrequency),
		Channels:        make([]WaveformChannel, n),
	}
	cfgStart := n - int(fd.ConfigSampleTotal)
	for c := 0; c < n; c++ {
		ch := WaveformChannel{Number: c, Values: make([]int16, m)}
		if c < len(fd.SampleMeanings) {
			ch.Meaning = fd.SampleMeanings[c]
		}
		if cfgStart >= 0 && c >= cfgStart && c-cfgStart < len(fd.ConfigSamples) {
			cfg := fd.ConfigSamples[c-cfgStart]
			ch.Configurable = &cfg
		}
		w.Channels[c] = ch
	}
	for k := 0; k < m; k++ {
		for c := 0; c < n; c++ {
			off := (k*n + c) * 2
			w.Channels[c].Values[k] = int16(binary.BigEndian.Uint16(b[off:]))
		}
	}
	return w, nil
}

// TimeOffsetMs 第 k 个采样点相对故障时刻的毫秒数
func (w Waveform) TimeOffsetMs(k int) float64 {
	if w.SampleFrequency == 0 {
		return 0
	}
	return float64(k-w.PrePoints) * 1000 / float64(w.SampleFrequency)
}

// Record 一条已解析的录波记录
type Record struct {
	Batch       string      `json:"batch"`
	Sn          string      `json:"sn"`
	RecordIndex int         `json:"recordIndex"`
	Failure     FailureData `json:"failure"`
	Waveform    Waveform    `json:"waveform"`
}

// ParseRecordFiles 解析一条记录的两个文件（内容为十六进制文本）
func ParseRecordFiles(f RecordFiles, deviceType string) (Record, error) {
	rec := Record{Batch: f.Batch, Sn: f.Sn, RecordIndex: f.Index}

	fdBytes, err := proto.DecodeHex(string(f.FailureData))
	if err != nil {
		return rec, fmt.Errorf("failuredata: %w", err)
	}
	if rec.Failure, err = ParseFailureData(fdBytes, deviceType); err != nil {
		return rec, fmt.Errorf("failuredata: %w", err)
	}

	wfBytes, err := proto.DecodeHex(string(f.WaveformData))
	if err != nil {
		return rec, fmt.Errorf("waveformdata: %w", err)
	}
	if rec.Waveform, err = ParseWaveform(wfBytes, rec.Failure); err != nil {
		return rec, fmt.Errorf("waveformdata: %w", err)
	}
	return rec, nil
}