package controller

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

	"ezops/middleware"
	"ezops/model"
	"ezops/pkg/logaccess"

	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

// LogProxyHandler Loki / ES 无状态查询代理
// 实时转发请求并解析展示字段，不将日志写入 AIOps 数据库 // Logan.Li
type LogProxyHandler struct {
	ds *LogDSHandler
	db *gorm.DB
}

const maxLogQueryLimit = 1000 // 单次查询返回日志行数硬上限（Loki limit / ES size 共用）// Logan.Li

func NewLogProxyHandler(ds *LogDSHandler, db *gorm.DB) *LogProxyHandler {
	return &LogProxyHandler{ds: ds, db: db}
}

// QueryLoki POST /api/v1/logs/loki/query
func (h *LogProxyHandler) QueryLoki(c *gin.Context) {
	var req struct {
		DatasourceID uint   `json:"datasource_id" binding:"required"`
		Query        string `json:"query" binding:"required"`
		Limit        int    `json:"limit"`
		Start        string `json:"start"`
		End          string `json:"end"`
		Direction    string `json:"direction"`
		Cursor       string `json:"cursor"` // 纳秒时间戳，向后翻页时作为 end // Logan.Li
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(400, model.Response{Code: 400, Message: err.Error()})
		return
	}
	allowed, denyMsg := logaccess.CanQuery(h.db, middleware.GetUserID(c), middleware.GetIsAdmin(c), logaccess.QueryContext{
		Engine: "loki", DatasourceID: req.DatasourceID, Query: req.Query,
	})
	if !allowed {
		c.JSON(403, model.Response{Code: 403, Message: denyMsg})
		return
	}
	ds, err := loadLogDS(h.ds, req.DatasourceID)
	if err != nil || ds.Type != "loki" {
		c.JSON(400, model.Response{Code: 400, Message: "Loki 数据源无效"})
		return
	}
	if req.Limit <= 0 {
		req.Limit = 200
	}
	if req.Limit > maxLogQueryLimit {
		req.Limit = maxLogQueryLimit
	}
	if req.Direction == "" {
		req.Direction = "backward"
	}
	end := time.Now()
	start := end.Add(-1 * time.Hour)
	if req.End != "" {
		if t, e := parseLogTime(req.End); e == nil {
			end = t
		}
	}
	if req.Start != "" {
		if t, e := parseLogTime(req.Start); e == nil {
			start = t
		}
	}
	if req.Cursor != "" {
		if n, err := strconv.ParseInt(strings.TrimSpace(req.Cursor), 10, 64); err == nil && n > 0 {
			end = time.Unix(0, n)
		}
	}

	params := url.Values{}
	params.Set("query", req.Query)
	params.Set("limit", strconv.Itoa(req.Limit))
	params.Set("direction", req.Direction)
	params.Set("start", fmt.Sprintf("%d", start.UnixNano()))
	params.Set("end", fmt.Sprintf("%d", end.UnixNano()))

	client := newLogHTTPClient(ds.SkipTLSVerify, time.Duration(60)*time.Second)
	target := ds.URL + "/loki/api/v1/query_range?" + params.Encode()
	httpReq, _ := http.NewRequest(http.MethodGet, target, nil)
	applyLogDSAuthV2(httpReq, ds)
	resp, err := client.Do(httpReq)
	if err != nil {
		c.JSON(502, model.Response{Code: 502, Message: "查询失败: " + err.Error()})
		return
	}
	defer resp.Body.Close()
	body, _ := io.ReadAll(resp.Body)
	if resp.StatusCode >= 400 {
		c.JSON(logProxyErrStatus(resp.StatusCode), model.Response{Code: logProxyErrStatus(resp.StatusCode), Message: "Loki 错误: " + string(body), Data: map[string]string{"category": logProxyErrCategory(resp.StatusCode)}})
		return
	}
	var raw map[string]interface{}
	_ = json.Unmarshal(body, &raw)
	entries := flattenLokiStreams(raw)
	nextCursor := ""
	if len(entries) > 0 && len(entries) >= req.Limit {
		nextCursor = lokiEntryCursor(entries[len(entries)-1].Timestamp)
	}
	c.JSON(200, model.Response{Code: 200, Data: gin.H{
		"entries": entries, "total": len(entries), "has_more": nextCursor != "", "next_cursor": nextCursor,
	}})
}

// QueryES POST /api/v1/logs/elasticsearch/query
func (h *LogProxyHandler) QueryES(c *gin.Context) {
	var req struct {
		DatasourceID uint                   `json:"datasource_id" binding:"required"`
		Index        string                 `json:"index"`
		Query        string                 `json:"query"`
		QueryBody    map[string]interface{} `json:"query_body"`
		Size         int                    `json:"size"`
		Start        string                 `json:"start"`
		End          string                 `json:"end"`
		SearchAfter  []interface{}          `json:"search_after"` // ES 深分页游标 // Logan.Li
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(400, model.Response{Code: 400, Message: err.Error()})
		return
	}
	index := req.Index
	if index == "" {
		if dsPreview, err := loadLogDS(h.ds, req.DatasourceID); err == nil {
			index = dsPreview.DefaultIndex
		}
	}
	if index == "" {
		index = "*"
	}
	allowed, denyMsg := logaccess.CanQuery(h.db, middleware.GetUserID(c), middleware.GetIsAdmin(c), logaccess.QueryContext{
		Engine: "elasticsearch", DatasourceID: req.DatasourceID, Index: index, Query: req.Query,
	})
	if !allowed {
		c.JSON(403, model.Response{Code: 403, Message: denyMsg})
		return
	}
	ds, err := loadLogDS(h.ds, req.DatasourceID)
	if err != nil || ds.Type != "elasticsearch" {
		c.JSON(400, model.Response{Code: 400, Message: "Elasticsearch 数据源无效"})
		return
	}
	if req.Size <= 0 {
		req.Size = 200
	}
	if req.Size > maxLogQueryLimit {
		req.Size = maxLogQueryLimit
	}

	searchBody := req.QueryBody
	if searchBody == nil {
		searchBody = map[string]interface{}{
			"size": req.Size,
			// ES 7+ 默认 track_total_hits 为 10000，必须显式开启才能返回真实命中总数 // Logan.Li
			"track_total_hits": true,
			"sort": []interface{}{
				map[string]interface{}{"@timestamp": map[string]string{"order": "desc", "unmapped_type": "date"}},
				map[string]interface{}{"_id": map[string]string{"order": "desc"}},
			},
			"query": map[string]interface{}{
				"bool": map[string]interface{}{
					"must": []interface{}{
						map[string]interface{}{"query_string": map[string]interface{}{"query": defaultESQuery(req.Query)}},
					},
				},
			},
		}
		if req.Start != "" || req.End != "" {
			// ES 7.2 date_time 仅接受 .SSSZ 格式（strict_date_optional_time 不含 epoch_millis）
			// 兼容各种前端时间格式：补全毫秒 // Logan.Li
			normalizeTime := func(s string) string {
				if s == "" {
					return s
				}
				// 空格 → T（兼容前端未正确转换的格式）// Logan.Li
				s = strings.Replace(s, " ", "T", 1)
				// 查找时间部分结束位置（Z 或 +）
				tzIdx := strings.IndexAny(s, "Z+")
				timePart := s
				tzPart := ""
				if tzIdx >= 0 {
					timePart = s[:tzIdx]
					tzPart = s[tzIdx:]
				}
				// 如果已有毫秒部分（.后跟数字），直接返回
				if dotIdx := strings.LastIndexByte(timePart, '.'); dotIdx >= 0 {
					if dotIdx+1 < len(timePart) && timePart[dotIdx+1] >= '0' && timePart[dotIdx+1] <= '9' {
						return s
					}
				}
				return timePart + ".000" + tzPart
			}
			rangeCond := map[string]interface{}{
				"bool": map[string]interface{}{
					"should": []interface{}{
						map[string]interface{}{"range": map[string]interface{}{"@timestamp": map[string]string{}}},
						map[string]interface{}{"range": map[string]interface{}{"timestamp": map[string]string{}}},
					},
					"minimum_should_match": 1,
				},
			}
			for _, clause := range rangeCond["bool"].(map[string]interface{})["should"].([]interface{}) {
				rng := clause.(map[string]interface{})["range"].(map[string]interface{})
				for _, v := range rng {
					r := v.(map[string]string)
					if req.Start != "" {
						r["gte"] = normalizeTime(req.Start)
					}
					if req.End != "" {
						r["lte"] = normalizeTime(req.End)
					}
				}
			}
			searchBody["query"] = map[string]interface{}{
				"bool": map[string]interface{}{
					"must": []interface{}{
						searchBody["query"],
						rangeCond,
					},
				},
			}
		}
	}
	if len(req.SearchAfter) > 0 {
		searchBody["search_after"] = req.SearchAfter
	}

	payload, _ := json.Marshal(searchBody)
	client := newLogHTTPClient(ds.SkipTLSVerify, 60*time.Second)
	target := fmt.Sprintf("%s/%s/_search", ds.URL, strings.Trim(index, "/"))
	httpReq, _ := http.NewRequest(http.MethodPost, target, bytes.NewReader(payload))
	httpReq.Header.Set("Content-Type", "application/json")
	applyLogDSAuthV2(httpReq, ds)
	resp, err := client.Do(httpReq)
	if err != nil {
		c.JSON(502, model.Response{Code: 502, Message: "查询失败: " + err.Error()})
		return
	}
	defer resp.Body.Close()
	body, _ := io.ReadAll(resp.Body)
	if resp.StatusCode >= 400 {
		c.JSON(logProxyErrStatus(resp.StatusCode), model.Response{Code: logProxyErrStatus(resp.StatusCode), Message: "ES 错误: " + string(body), Data: map[string]string{"category": logProxyErrCategory(resp.StatusCode)}})
		return
	}
	var raw map[string]interface{}
	_ = json.Unmarshal(body, &raw)
	entries, nextSearchAfter := flattenESEntries(raw)
	total := esHitsTotal(raw)
	hasMore := len(entries) >= req.Size && len(nextSearchAfter) > 0
	c.JSON(200, model.Response{Code: 200, Data: gin.H{
		"entries": entries, "total": total, "has_more": hasMore, "search_after": nextSearchAfter,
	}})
}

// logProxyErrStatus 把下游 HTTP 状态码映射为合适的 API 状态码 // Logan.Li
func logProxyErrStatus(status int) int {
	if status >= 400 && status < 500 {
		return 400
	}
	return 502
}

// logProxyErrCategory 对下游错误进行分类，便于前端展示中文提示 // Logan.Li
func logProxyErrCategory(status int) string {
	switch status {
	case 401:
		return "auth_failed"
	case 403:
		return "forbidden"
	case 400, 404:
		return "bad_request"
	default:
		if status >= 500 {
			return "server_error"
		}
		return "unknown"
	}
}

// formatLokiTimestamp 将 Loki 纳秒/秒级（含科学计数法）时间戳转为 RFC3339 // Logan.Li
func formatLokiTimestamp(ts string) string {
	ts = strings.TrimSpace(ts)
	if f, err := strconv.ParseFloat(ts, 64); err == nil {
		if strings.Contains(ts, ".") || strings.Contains(strings.ToLower(ts), "e") {
			sec := int64(f)
			nsec := int64((f - float64(sec)) * 1e9)
			return time.Unix(sec, nsec).UTC().Format(time.RFC3339)
		}
	}
	if n, err := strconv.ParseInt(ts, 10, 64); err == nil {
		if n > 1e15 {
			return time.Unix(0, n).UTC().Format(time.RFC3339Nano)
		}
		if n > 1e12 {
			return time.UnixMilli(n).UTC().Format(time.RFC3339Nano)
		}
		return time.Unix(n, 0).UTC().Format(time.RFC3339)
	}
	return ts
}

func parseLogTime(s string) (time.Time, error) {
	if n, err := strconv.ParseInt(s, 10, 64); err == nil {
		if n > 1e15 {
			return time.Unix(0, n), nil
		}
		return time.Unix(n, 0), nil
	}
	// 解析 ISO8601（含 .SSSZ 毫秒后缀，如 2026-06-20T09:33:17.000Z）
	return time.Parse(time.RFC3339Nano, s)
}

func defaultESQuery(q string) string {
	if strings.TrimSpace(q) == "" {
		return "*"
	}
	return q
}

type logEntryRow struct {
	Timestamp string            `json:"timestamp"`
	Level     string            `json:"level,omitempty"`
	Message   string            `json:"message"`
	Labels    map[string]string `json:"labels,omitempty"`
	Raw       string            `json:"raw,omitempty"`
}

func flattenLokiStreams(raw map[string]interface{}) []logEntryRow {
	out := []logEntryRow{}
	data, _ := raw["data"].(map[string]interface{})
	result, _ := data["result"].([]interface{})
	for _, item := range result {
		stream, _ := item.(map[string]interface{})
		labels, _ := stream["stream"].(map[string]interface{})
		labelMap := map[string]string{}
		for k, v := range labels {
			labelMap[k] = fmt.Sprintf("%v", v)
		}
		values, _ := stream["values"].([]interface{})
		for _, val := range values {
			pair, _ := val.([]interface{})
			if len(pair) < 2 {
				continue
			}
			ts := formatLokiTimestamp(fmt.Sprintf("%v", pair[0]))
			msg := fmt.Sprintf("%v", pair[1])
			out = append(out, logEntryRow{
				Timestamp: ts,
				Level:     labelMap["level"],
				Message:   msg,
				Labels:    labelMap,
				Raw:       msg,
			})
		}
	}
	return out
}

func flattenESEntries(raw map[string]interface{}) ([]logEntryRow, []interface{}) {
	out := []logEntryRow{}
	var nextAfter []interface{}
	hitsWrap, _ := raw["hits"].(map[string]interface{})
	hits, _ := hitsWrap["hits"].([]interface{})
	for i, h := range hits {
		doc, _ := h.(map[string]interface{})
		src, _ := doc["_source"].(map[string]interface{})
		if src == nil {
			continue
		}
		msg := pickESMessage(src)
		level := pickESLevel(src)
		ts, _ := src["@timestamp"].(string)
		if ts == "" {
			ts = fmt.Sprintf("%v", src["timestamp"])
		}
		rawBytes, _ := json.Marshal(src)
		out = append(out, logEntryRow{
			Timestamp: ts,
			Level:     level,
			Message:   msg,
			Labels:    extractESLabels(src),
			Raw:       string(rawBytes),
		})
		if i == len(hits)-1 {
			if sortVals, ok := doc["sort"].([]interface{}); ok {
				nextAfter = sortVals
			}
		}
	}
	return out, nextAfter
}

// lokiEntryCursor 从 RFC3339 时间戳反推纳秒游标 // Logan.Li
func lokiEntryCursor(ts string) string {
	if t, err := time.Parse(time.RFC3339Nano, ts); err == nil {
		return strconv.FormatInt(t.UnixNano(), 10)
	}
	if t, err := time.Parse(time.RFC3339, ts); err == nil {
		return strconv.FormatInt(t.UnixNano(), 10)
	}
	return ""
}

// extractESLabels 从 _source 提取常用字段作为 labels（便于字段过滤）// Logan.Li
func extractESLabels(src map[string]interface{}) map[string]string {
	labels := map[string]string{}
	for _, key := range []string{"app", "service", "service_name", "host.name", "kubernetes.namespace", "namespace", "container.name", "level"} {
		if v := pickESField(src, key); v != "" {
			labels[key] = v
		}
	}
	if lv := pickESLevel(src); lv != "" {
		labels["level"] = lv
	}
	return labels
}

func pickESField(src map[string]interface{}, key string) string {
	if strings.Contains(key, ".") {
		parts := strings.Split(key, ".")
		cur := interface{}(src)
		for _, p := range parts {
			m, ok := cur.(map[string]interface{})
			if !ok {
				return ""
			}
			cur, ok = m[p]
			if !ok {
				return ""
			}
		}
		return stringifyESField(cur)
	}
	if v, ok := src[key]; ok {
		return stringifyESField(v)
	}
	return ""
}

// esHitsTotal 从 ES 响应中提取真实命中总数（兼容 ES 7+ total.value 与旧版 total）// Logan.Li
func esHitsTotal(raw map[string]interface{}) int64 {
	hitsWrap, _ := raw["hits"].(map[string]interface{})
	if total, ok := hitsWrap["total"].(map[string]interface{}); ok {
		if v, ok := total["value"].(float64); ok {
			return int64(v)
		}
	}
	if v, ok := hitsWrap["total"].(float64); ok {
		return int64(v)
	}
	return 0
}

// pickESLevel 提取日志级别（兼容顶层 level 与 ECS/Filebeat 的 log.level） // Logan.Li
func pickESLevel(src map[string]interface{}) string {
	if v, ok := src["level"].(string); ok && v != "" {
		return v
	}
	if v, ok := src["log.level"].(string); ok && v != "" {
		return v
	}
	if logObj, ok := src["log"].(map[string]interface{}); ok {
		if v, ok := logObj["level"].(string); ok && v != "" {
			return v
		}
	}
	return ""
}

// stringifyESField 将 ES 字段值转为展示字符串 // Logan.Li
func stringifyESField(v interface{}) string {
	switch t := v.(type) {
	case string:
		return t
	case float64:
		return fmt.Sprintf("%v", t)
	case bool:
		return fmt.Sprintf("%t", t)
	default:
		return ""
	}
}

// pickESMessage 提取日志正文（兼容 message / ECS log.original / event.original） // Logan.Li
func pickESMessage(src map[string]interface{}) string {
	for _, key := range []string{"message", "msg", "content", "event.original"} {
		if v, ok := src[key]; ok {
			if s := stringifyESField(v); s != "" {
				return s
			}
		}
	}
	if logObj, ok := src["log"].(map[string]interface{}); ok {
		for _, key := range []string{"original", "message"} {
			if v, ok := logObj[key]; ok {
				if s := stringifyESField(v); s != "" {
					return s
				}
			}
		}
	}
	// 顶层 log 为字符串时（部分旧索引）
	if v, ok := src["log"]; ok {
		if s := stringifyESField(v); s != "" {
			return s
		}
	}
	b, _ := json.Marshal(src)
	if len(b) > 500 {
		return string(b[:500]) + "..."
	}
	return string(b)
}