package handler

import (
	"bytes"
	"encoding/csv"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"strings"
	"unicode"

	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/gin-gonic/gin"
	"github.com/luxsin/app-api/internal/storage"
	"github.com/luxsin/app-api/pkg/encode"
	"go.uber.org/zap"
)

type ModelCSVHandler struct {
	s3  *storage.S3Storage
	log *zap.Logger
}

func NewModelCSVHandler(s3 *storage.S3Storage, log *zap.Logger) *ModelCSVHandler {
	return &ModelCSVHandler{s3: s3, log: log}
}

// GetModelCSV 从 S3 读取耳机 CSV 频响数据
//
//	@Summary		获取耳机原始频响 CSV 数据
//	@Description	从 S3 读取指定机型的测量 CSV 数据，返回 frequency 和 raw 数组
//	@Tags			Curve
//	@Produce		json
//	@Param			brand		query		string			true	"品牌名称"
//	@Param			model		query		string			true	"型号名称"
//	@Param			form		query		string			true	"耳机类型 (in-ear/over-ear)"
//	@Param			base64Resp	query		string			false	"是否返回 base64 编码响应"
//	@Success		200			{object}	map[string]any	"成功返回 frequency 和 raw 数组"
//	@Failure		400			{object}	map[string]any	"参数校验失败"
//	@Failure		500			{object}	object
//	@Router			/audio/getModelCSV [get]
//
// GET /audio/getModelCSV?brand=Abyss&model=Dinan DZ&form=over-ear&base64Resp=true
func (h *ModelCSVHandler) GetModelCSV(c *gin.Context) {
	brand := strings.TrimSpace(queryParam(c, "brand"))
	model := strings.TrimSpace(queryParam(c, "model"))
	form := strings.TrimSpace(queryParam(c, "form"))
	base64Resp := encode.ParseBase64Param(c)

	if brand == "" || model == "" || form == "" {
		h.writeModelCSVResponse(c, base64Resp, gin.H{
			"code": 400,
			"msg":  "参数校验失败",
		})
		return
	}

	key := modelCSVKey(brand, model, form)
	ctx := c.Request.Context()

	h.log.Info("reading csv from s3", zap.String("key", key))
	data, err := h.s3.GetObject(ctx, key)
	if err != nil {
		var noSuchKey *types.NoSuchKey
		if errors.As(err, &noSuchKey) {
			h.log.Info("model csv not found in s3", zap.String("key", key))
			h.writeModelCSVResponse(c, base64Resp, gin.H{
				"code": 0,
				"msg":  "无曲线数据",
			})
			return
		}
		h.log.Error("get model csv from s3 failed",
			zap.String("key", key),
			zap.Error(err),
		)
		h.writeModelCSVResponse(c, base64Resp, gin.H{
			"code": 500,
			"msg":  "系统错误",
		})
		return
	}

	parsed, err := parseCSVData(data)
	if err != nil || parsed == nil {
		h.log.Error("parse model csv failed", zap.String("key", key), zap.Error(err))
		h.writeModelCSVResponse(c, base64Resp, gin.H{
			"code": 0,
			"msg":  "无曲线数据",
		})
		return
	}

	h.writeModelCSVResponse(c, base64Resp, gin.H{
		"code":      200,
		"msg":       "操作成功",
		"frequency": parsed["frequency"],
		"raw":       parsed["raw"],
	})
}

func targetCSVKey(file string) string {
	file = strings.TrimPrefix(strings.TrimSpace(file), "/")
	return "autoeq/targets/" + file
}

func modelCSVKey(brand, model, form string) string {
	filename := brand + " " + model + ".csv"
	return fmt.Sprintf("autoeq/measurements/Eafonyoung/data/%s/%s/%s",
		form, brandPrefix(brand), filename)
}

func brandPrefix(brand string) string {
	runes := []rune(brand)
	if len(runes) == 0 {
		return ""
	}
	first := runes[0]
	if unicode.IsLetter(first) && unicode.IsLower(first) {
		return strings.ToUpper(string(first))
	}
	return string(first)
}

func parseCSVData(data []byte) (map[string]any, error) {
	reader := csv.NewReader(bytes.NewReader(data))
	if _, err := reader.Read(); err != nil {
		return nil, fmt.Errorf("read csv header: %w", err)
	}

	frequency := make([]float64, 0)
	raw := make([]float64, 0)

	for {
		record, err := reader.Read()
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, fmt.Errorf("read csv row: %w", err)
		}
		if len(record) < 2 {
			continue
		}
		freq, err1 := strconv.ParseFloat(record[0], 64)
		val, err2 := strconv.ParseFloat(record[1], 64)
		if err1 != nil || err2 != nil {
			continue
		}
		frequency = append(frequency, freq)
		raw = append(raw, val)
	}

	if len(frequency) == 0 {
		return nil, nil
	}

	return map[string]any{
		"frequency": frequency,
		"raw":       raw,
	}, nil
}

func (h *ModelCSVHandler) writeModelCSVResponse(c *gin.Context, base64Resp bool, data any) {
	if base64Resp {
		encoded, err := encode.EncodeJSON(data)
		if err != nil {
			h.log.Error("encode response failed", zap.Error(err))
			c.JSON(http.StatusOK, gin.H{
				"code": 500,
				"msg":  "系统错误",
			})
			return
		}
		c.String(http.StatusOK, encoded)
		return
	}
	c.JSON(http.StatusOK, data)
}