package handler

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"

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

type CurveHandler struct {
	repo  *repository.CurveRepository
	cache *cache.CurveCache
	cfg   config.EqualizeConfig
	s3    *storage.S3Storage
	log   *zap.Logger
}

const defaultModelCurveTarget = "Harman over-ear 2018"

func NewCurveHandler(repo *repository.CurveRepository, curveCache *cache.CurveCache, cfg config.EqualizeConfig, s3 *storage.S3Storage, log *zap.Logger) *CurveHandler {
	return &CurveHandler{repo: repo, cache: curveCache, cfg: cfg, s3: s3, log: log}
}

// ModelCurve 获取机型默认曲线（固定 target: Harman over-ear 2018）
// GET /audio/modelCurve?brand=xxx&name=xxx&base64Resp=true
func (h *CurveHandler) ModelCurve(c *gin.Context) {
	brand := strings.TrimSpace(queryParam(c, "brand"))
	name := strings.TrimSpace(queryParam(c, "name"))
	base64Resp := encode.ParseBase64Param(c)

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

	ctx := c.Request.Context()

	result, err := h.getCurvePoint(ctx, brand, name, defaultModelCurveTarget)
	if err != nil {
		h.log.Error("get model curve failed", zap.Error(err))
		response.InternalError(c, "获取曲线数据失败")
		return
	}

	if result == "" {
		h.writeCurveResponse(c, base64Resp, gin.H{
			"code": 0,
			"msg":  "无曲线数据",
		})
		return
	}

	var resp map[string]any
	if err := json.Unmarshal([]byte(result), &resp); err != nil {
		response.InternalError(c, "解析曲线数据失败")
		return
	}

	h.writeCurveResponse(c, base64Resp, resp)
}

// GetCurve 获取目标曲线
// GET /audio/getCurve?brand=xxx&name=xxx&target=xxx&base64Resp=true
func (h *CurveHandler) GetCurve(c *gin.Context) {
	brand := strings.TrimSpace(queryParam(c, "brand"))
	name := strings.TrimSpace(queryParam(c, "name"))
	// target 使用标准 query 解码：+ 表示空格（如 Harman+over-ear+2018 → Harman over-ear 2018）
	target := strings.TrimSpace(c.Query("target"))
	base64Resp := encode.ParseBase64Param(c)

	if brand == "" || name == "" || target == "" {
		response.BadRequest(c, "brand、name和target参数不能为空")
		return
	}

	ctx := c.Request.Context()

	result, err := h.getCurvePoint(ctx, brand, name, target)
	if err != nil {
		h.log.Error("get curve point failed", zap.Error(err))
		response.InternalError(c, "获取曲线数据失败")
		return
	}

	if result == "" {
		response.Fail(c, http.StatusOK, 0, "无曲线数据")
		return
	}

	// 解析 JSON 结果，只提取 parametric_eq
	var resp map[string]any
	if err := json.Unmarshal([]byte(result), &resp); err != nil {
		response.InternalError(c, "解析曲线数据失败")
		return
	}

	parametricEq, _ := resp["parametric_eq"]

	resultData := gin.H{
		"code":          200,
		"msg":           "操作成功",
		"parametric_eq": parametricEq,
	}

	if base64Resp {
		encoded, err := encode.EncodeJSON(resultData)
		if err != nil {
			h.log.Error("encode response failed", zap.Error(err))
			response.InternalError(c, "编码响应失败")
			return
		}
		c.String(http.StatusOK, encoded)
		return
	}

	c.JSON(http.StatusOK, resultData)
}

func (h *CurveHandler) writeCurveResponse(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))
			response.InternalError(c, "编码响应失败")
			return
		}
		c.String(http.StatusOK, encoded)
		return
	}
	c.JSON(http.StatusOK, data)
}

// getCurvePoint 获取曲线数据：先查缓存，缓存不存在则请求 EQ 接口并缓存结果
func (h *CurveHandler) getCurvePoint(ctx context.Context, brand, name, target string) (string, error) {
	data, acquired, err := h.cache.GetWithLock(ctx, brand, name, target)
	if err != nil {
		return "", err
	}

	// 缓存命中
	if data != "" && !acquired {
		h.log.Info("curve cache hit", zap.String("brand", brand), zap.String("name", name), zap.String("target", target))
		return data, nil
	}

	// 获取了锁，缓存仍然为空，需要请求 EQ 接口
	if acquired {
		h.log.Info("curve cache miss, requesting eq api", zap.String("brand", brand), zap.String("name", name), zap.String("target", target))
		result, eqErr := h.getCurvePointFromPEQ(ctx, brand, name, target)
		if eqErr != nil {
			// 释放锁
			if lockErr := h.cache.ReleaseLock(ctx, brand, name, target); lockErr != nil {
				h.log.Warn("release curve lock failed", zap.Error(lockErr))
			}
			return "", eqErr
		}
		// 释放锁
		if lockErr := h.cache.ReleaseLock(ctx, brand, name, target); lockErr != nil {
			h.log.Warn("release curve lock failed", zap.Error(lockErr))
		}

		if result != "" {
			// 缓存结果
			if cacheErr := h.cache.Set(ctx, brand, name, target, result); cacheErr != nil {
				h.log.Warn("curve cache set failed", zap.Error(cacheErr))
			}
			return result, nil
		}
		return "", nil
	}

	// 未获取锁（其他请求正在处理），等待后重试
	time.Sleep(100 * time.Millisecond)
	return h.getCurvePoint(ctx, brand, name, target)
}

// getCurvePointFromPEQ 从 EQ 接口获取曲线数据
func (h *CurveHandler) getCurvePointFromPEQ(ctx context.Context, brand, name, targetName string) (string, error) {
	m, err := h.repo.GetModelByBrandAndName(ctx, brand, name)
	if err != nil {
		return "", fmt.Errorf("query model: %w", err)
	}
	if m == nil {
		return "", nil
	}

	t, err := h.repo.GetTargetByLabel(ctx, targetName)
	if err != nil {
		return "", fmt.Errorf("query target: %w", err)
	}
	if t == nil {
		return "", nil
	}

	// 确定 headPhone 名称
	headPhone := brand + " " + name
	if m.EqKey != nil && *m.EqKey == "name" {
		headPhone = name
	}

	// 获取 measurement 数据（仅 Eafonyoung 源需要从 S3 读 CSV）
	var measurement map[string]any
	if m.Source != nil && *m.Source == "Eafonyoung" {
		key := modelCSVKey(brand, name, deref(m.Form))
		measurement, err = h.readCSVFromS3(ctx, key)
		if err != nil || measurement == nil {
			return "", nil
		}
	}

	// 构建请求
	var targetParam any
	var targetRaw map[string]any

	if bool(t.ReadCSV) {
		key := targetCSVKey(deref(t.File))
		targetRaw, err = h.readCSVFromS3(ctx, key)
		if err != nil || targetRaw == nil {
			return "", nil
		}
		targetParam = targetRaw
	} else {
		targetParam = targetName
	}

	// 解析 bassBoost
	var bassBoost map[string]any
	if t.BassBoost != nil {
		if err := json.Unmarshal([]byte(*t.BassBoost), &bassBoost); err != nil {
			h.log.Warn("parse bassBoost failed", zap.Error(err))
			bassBoost = map[string]any{"gain": 0, "fc": 100, "q": 0.7}
		}
	} else {
		bassBoost = map[string]any{"gain": 0, "fc": 100, "q": 0.7}
	}

	resp, err := h.reqEqualize(headPhone, measurement, targetParam, bassBoost, deref(m.Source), deref(m.Rig))
	if err != nil {
		return "", err
	}

	return resp, nil
}

// reqEqualize 调用 autoeq API
func (h *CurveHandler) reqEqualize(headPhone string, measurement map[string]any, target any, bassBoost map[string]any, source, rig string) (string, error) {
	gain := floatVal(bassBoost, "gain", 0)
	fc := intVal(bassBoost, "fc", 100)
	q := floatVal(bassBoost, "q", 0.7)

	reqBody := map[string]any{
		"target":                                target,
		"sound_signature":                       nil,
		"sound_signature_smoothing_window_size": 1,
		"bass_boost_gain":                       gain,
		"bass_boost_fc":                         fc,
		"bass_boost_q":                          q,
		"treble_boost_gain":                     0,
		"treble_boost_fc":                       10000,
		"treble_boost_q":                        0.7,
		"tilt":                                  0,
		"fs":                                    48000,
		"bit_depth":                             16,
		"phase":                                 "minimum",
		"f_res":                                 16,
		"preamp":                                0,
		"max_gain":                              12,
		"max_slope":                             18,
		"window_size":                           0.08,
		"treble_window_size":                    2,
		"treble_f_lower":                        6000,
		"treble_f_upper":                        8000,
		"treble_gain_k":                         1,
		"graphic_eq":                            false,
		"parametric_eq":                         true,
		"fixed_band_eq":                         false,
		"convolution_eq":                        false,
		"source":                                source,
		"rig":                                   rig,
		"parametric_eq_config":                  "MINIDSP_IL_DSP",
		"response": map[string]any{
			"fr_f_step":  1.02,
			"base64fp16": false,
			"fr_fields":  []string{"raw"},
		},
	}

	// measurement 或 headPhone 二选一
	if measurement != nil {
		reqBody["measurement"] = measurement
	} else if headPhone != "" {
		reqBody["name"] = headPhone
	}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return "", fmt.Errorf("marshal eq request: %w", err)
	}

	httpReq, err := http.NewRequestWithContext(context.Background(), http.MethodPost, h.cfg.APIURL, bytes.NewReader(jsonData))
	if err != nil {
		return "", fmt.Errorf("create eq request: %w", err)
	}
	httpReq.Header.Set("Content-Type", "application/json")

	start := time.Now()
	client := &http.Client{Timeout: 10 * time.Second}
	httpResp, err := client.Do(httpReq)
	elapsed := time.Since(start)
	h.log.Info("eq api response",
		zap.String("headPhone", headPhone),
		zap.Duration("latency", elapsed),
		zap.String("url", h.cfg.APIURL),
	)
	if err != nil {
		h.log.Error("eq api request failed", zap.Duration("latency", elapsed), zap.Error(err))
		return "", fmt.Errorf("call eq api: %w", err)
	}
	defer httpResp.Body.Close()

	body, err := io.ReadAll(httpResp.Body)
	if err != nil {
		return "", fmt.Errorf("read eq response: %w", err)
	}

	if httpResp.StatusCode != http.StatusOK {
		h.log.Warn("eq api returned non-200", zap.Int("status", httpResp.StatusCode), zap.String("body", string(body)))
		return "", fmt.Errorf("eq api status: %d", httpResp.StatusCode)
	}

	var eqResp map[string]any
	if err := json.Unmarshal(body, &eqResp); err != nil {
		return "", fmt.Errorf("unmarshal eq response: %w", err)
	}

	parametricEq, _ := eqResp["parametric_eq"].(map[string]any)
	if parametricEq == nil {
		result := map[string]any{
			"code":  200,
			"msg":   "req param error",
			"param": reqBody,
		}
		resultJSON, _ := json.Marshal(result)
		return string(resultJSON), nil
	}

	result := map[string]any{
		"code":          200,
		"msg":           "ok",
		"parametric_eq": eqResp["parametric_eq"],
		"fr":            eqResp["fr"],
	}
	resultJSON, _ := json.Marshal(result)
	return string(resultJSON), nil
}

// readCSVFromS3 从 S3 读取 CSV 并返回 {frequency: [...], raw: [...]}
func (h *CurveHandler) readCSVFromS3(ctx context.Context, key string) (map[string]any, error) {
	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("csv not found in s3", zap.String("key", key))
			return nil, nil
		}
		return nil, fmt.Errorf("get csv from s3: %w", err)
	}

	parsed, err := parseCSVData(data)
	if err != nil {
		return nil, fmt.Errorf("parse csv: %w", err)
	}
	return parsed, nil
}

// 辅助函数
func deref(s *string) string {
	if s == nil {
		return ""
	}
	return *s
}

func floatVal(m map[string]any, key string, defaultVal float64) float64 {
	v, ok := m[key]
	if !ok {
		return defaultVal
	}
	switch n := v.(type) {
	case float64:
		return n
	case int:
		return float64(n)
	case string:
		f, err := strconv.ParseFloat(n, 64)
		if err != nil {
			return defaultVal
		}
		return f
	default:
		return defaultVal
	}
}

func intVal(m map[string]any, key string, defaultVal int) int {
	v, ok := m[key]
	if !ok {
		return defaultVal
	}
	switch n := v.(type) {
	case float64:
		return int(n)
	case int:
		return n
	case string:
		i, err := strconv.Atoi(n)
		if err != nil {
			return defaultVal
		}
		return i
	default:
		return defaultVal
	}
}

// queryParam 从 URL 原始 query 中获取参数，保留 + 为字面量而非空格
func queryParam(c *gin.Context, key string) string {
	vals, ok := c.Request.URL.Query()[key]
	if !ok || len(vals) == 0 {
		return ""
	}
	// c.Query() 会把 + 解码为空格，这里从原始 query 手动解码，+ 保留为 +
	if strings.Contains(vals[0], " ") {
		rawQuery := c.Request.URL.RawQuery
		for _, pair := range strings.Split(rawQuery, "&") {
			kv := strings.SplitN(pair, "=", 2)
			if len(kv) == 2 && kv[0] == key {
				decoded, err := url.PathUnescape(strings.ReplaceAll(kv[1], "+", "%2B"))
				if err == nil {
					return decoded
				}
			}
		}
	}
	return vals[0]
}