package handlers

import (
	"fmt"
	"net/http"
	"regexp"
	"strings"
	"time"

	"ezops/internal/models"

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

// SQLAuditHandler SQL审计处理器 // Logan.Li
type SQLAuditHandler struct {
	db *gorm.DB
}

func NewSQLAuditHandler(db *gorm.DB) *SQLAuditHandler {
	return &SQLAuditHandler{db: db}
}

// ListRecords 获取审计记录列表 // Logan.Li
func (h *SQLAuditHandler) ListRecords(c *gin.Context) {
	// 分页
	page := 1
	pageSize := 50
	if c.Query("page") != "" {
		fmt.Sscanf(c.Query("page"), "%d", &page)
	}
	if c.Query("page_size") != "" {
		fmt.Sscanf(c.Query("page_size"), "%d", &pageSize)
	}
	if page < 1 {
		page = 1
	}
	if pageSize < 1 || pageSize > 500 {
		pageSize = 50
	}

	query := h.db.Model(&models.SQLAuditRecord{})

	// 筛选
	if status := c.Query("status"); status != "" {
		query = query.Where("status = ?", status)
	}
	if risk := c.Query("risk_level"); risk != "" {
		query = query.Where("risk_level = ?", risk)
	}
	if keyword := c.Query("keyword"); keyword != "" {
		query = query.Where("sql_content LIKE ? OR database_name LIKE ? OR executor LIKE ?",
			"%"+keyword+"%", "%"+keyword+"%", "%"+keyword+"%")
	}

	var total int64
	query.Count(&total)

	var records []models.SQLAuditRecord
	query.Order("created_at DESC").Offset((page - 1) * pageSize).Limit(pageSize).Find(&records)

	c.JSON(http.StatusOK, models.Response{
		Code:    200,
		Message: "success",
		Data: models.ListResponse{
			List:  records,
			Total: total,
		},
	})
}

// GetRecord 获取审计记录详情 // Logan.Li
func (h *SQLAuditHandler) GetRecord(c *gin.Context) {
	id := c.Param("id")
	var record models.SQLAuditRecord
	if err := h.db.First(&record, id).Error; err != nil {
		c.JSON(http.StatusNotFound, models.Response{Code: 404, Message: "记录不存在"})
		return
	}
	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "success", Data: record})
}

// AnalyzeSQL 分析SQL并创建审计记录 // Logan.Li
func (h *SQLAuditHandler) AnalyzeSQL(c *gin.Context) {
	var req models.AnalyzeSQLRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "参数错误"})
		return
	}
	if strings.TrimSpace(req.SQL) == "" {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "SQL不能为空"})
		return
	}

	sqlUpper := strings.ToUpper(strings.TrimSpace(req.SQL))

	// 判断 SQL 类型
	sqlType := detectSQLType(sqlUpper)

	// 提取表名
	tableName := extractTableName(sqlUpper)

	// 风险分析
	riskLevel, matchedRules := h.analyzeRisk(sqlUpper)

	// 获取当前用户
	username := c.GetString("username")
	if username == "" {
		username = "system"
	}

	rulesJSON := "[]"
	if len(matchedRules) > 0 {
		rulesJSON = fmt.Sprintf(`["%s"]`, strings.Join(matchedRules, `","`))
	}

	record := models.SQLAuditRecord{
		SQLContent:   req.SQL,
		SQLType:      sqlType,
		DatabaseName: req.DatabaseName,
		TargetTable:  tableName,
		RiskLevel:    riskLevel,
		RiskRules:    rulesJSON,
		Status:       "pending",
		Executor:     username,
		Application:  req.Application,
		SourceIP:     c.ClientIP(),
	}

	if err := h.db.Create(&record).Error; err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "创建审计记录失败"})
		return
	}

	c.JSON(http.StatusOK, models.Response{
		Code:    200,
		Message: "分析完成",
		Data: models.AnalyzeSQLResponse{
			ID:        int64(record.ID),
			RiskLevel: riskLevel,
			RiskRules: matchedRules,
			SQLType:   sqlType,
			TableName: tableName,
		},
	})
}

// ApproveRecord 审批通过 // Logan.Li
func (h *SQLAuditHandler) ApproveRecord(c *gin.Context) {
	id := c.Param("id")
	username := c.GetString("username")
	if username == "" {
		username = "admin"
	}

	result := h.db.Model(&models.SQLAuditRecord{}).Where("id = ? AND status = ?", id, "pending").
		Updates(map[string]interface{}{"status": "approved", "approver": username})
	if result.Error != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "审批失败"})
		return
	}
	if result.RowsAffected == 0 {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "记录不存在或非待审批状态"})
		return
	}
	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "审批通过"})
}

// RejectRecord 审批驳回 // Logan.Li
func (h *SQLAuditHandler) RejectRecord(c *gin.Context) {
	id := c.Param("id")
	username := c.GetString("username")
	if username == "" {
		username = "admin"
	}

	result := h.db.Model(&models.SQLAuditRecord{}).Where("id = ? AND status = ?", id, "pending").
		Updates(map[string]interface{}{"status": "rejected", "approver": username})
	if result.Error != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "驳回失败"})
		return
	}
	if result.RowsAffected == 0 {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "记录不存在或非待审批状态"})
		return
	}
	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "已驳回"})
}

// ExecuteRecord 执行SQL（模拟） // Logan.Li
func (h *SQLAuditHandler) ExecuteRecord(c *gin.Context) {
	id := c.Param("id")

	var record models.SQLAuditRecord
	if err := h.db.First(&record, id).Error; err != nil {
		c.JSON(http.StatusNotFound, models.Response{Code: 404, Message: "记录不存在"})
		return
	}

	if record.Status != "approved" {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "只能执行已审批的SQL"})
		return
	}

	now := time.Now()
	// 模拟执行（真实环境需连接目标数据库执行）
	h.db.Model(&record).Updates(map[string]interface{}{
		"status":          "executed",
		"execute_time":    now,
		"affected_rows":   0,
		"execution_time":  10,
	})

	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "SQL执行成功"})
}

// DeleteRecord 删除审计记录 // Logan.Li
func (h *SQLAuditHandler) DeleteRecord(c *gin.Context) {
	id := c.Param("id")
	if err := h.db.Delete(&models.SQLAuditRecord{}, id).Error; err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "删除失败"})
		return
	}
	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "已删除"})
}

// ==================== 审计规则管理 ====================

// ListRules 获取审计规则列表 // Logan.Li
func (h *SQLAuditHandler) ListRules(c *gin.Context) {
	var rules []models.SQLAuditRule
	h.db.Order("created_at DESC").Find(&rules)

	c.JSON(http.StatusOK, models.Response{
		Code:    200,
		Message: "success",
		Data: models.ListResponse{
			List:  rules,
			Total: int64(len(rules)),
		},
	})
}

// CreateRule 创建审计规则 // Logan.Li
func (h *SQLAuditHandler) CreateRule(c *gin.Context) {
	var rule models.SQLAuditRule
	if err := c.ShouldBindJSON(&rule); err != nil {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "参数错误"})
		return
	}
	if rule.Name == "" {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "规则名称不能为空"})
		return
	}
	if rule.Severity == "" {
		rule.Severity = "medium"
	}
	rule.Enabled = true

	if err := h.db.Create(&rule).Error; err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "创建规则失败"})
		return
	}
	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "规则已创建", Data: rule})
}

// UpdateRule 更新审计规则 // Logan.Li
func (h *SQLAuditHandler) UpdateRule(c *gin.Context) {
	id := c.Param("id")
	var rule models.SQLAuditRule
	if err := h.db.First(&rule, id).Error; err != nil {
		c.JSON(http.StatusNotFound, models.Response{Code: 404, Message: "规则不存在"})
		return
	}

	var req models.SQLAuditRule
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "参数错误"})
		return
	}

	h.db.Model(&rule).Updates(map[string]interface{}{
		"name":        req.Name,
		"description": req.Description,
		"pattern":     req.Pattern,
		"severity":    req.Severity,
		"category":    req.Category,
		"enabled":     req.Enabled,
	})

	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "规则已更新", Data: rule})
}

// DeleteRule 删除审计规则 // Logan.Li
func (h *SQLAuditHandler) DeleteRule(c *gin.Context) {
	id := c.Param("id")
	if err := h.db.Delete(&models.SQLAuditRule{}, id).Error; err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "删除失败"})
		return
	}
	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "规则已删除"})
}

// ToggleRule 启用/禁用规则 // Logan.Li
func (h *SQLAuditHandler) ToggleRule(c *gin.Context) {
	id := c.Param("id")
	var rule models.SQLAuditRule
	if err := h.db.First(&rule, id).Error; err != nil {
		c.JSON(http.StatusNotFound, models.Response{Code: 404, Message: "规则不存在"})
		return
	}
	h.db.Model(&rule).Update("enabled", !rule.Enabled)
	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "状态已更新"})
}

// ==================== 辅助函数 ====================

// detectSQLType 检测SQL类型 // Logan.Li
func detectSQLType(sqlUpper string) string {
	switch {
	case strings.HasPrefix(sqlUpper, "DROP"):
		return "DDL-DROP"
	case strings.HasPrefix(sqlUpper, "TRUNCATE"):
		return "DDL-TRUNCATE"
	case strings.HasPrefix(sqlUpper, "ALTER"):
		return "DDL-ALTER"
	case strings.HasPrefix(sqlUpper, "CREATE"):
		return "DDL-CREATE"
	case strings.HasPrefix(sqlUpper, "DELETE"):
		return "DML-DELETE"
	case strings.HasPrefix(sqlUpper, "UPDATE"):
		return "DML-UPDATE"
	case strings.HasPrefix(sqlUpper, "INSERT"):
		return "DML-INSERT"
	case strings.HasPrefix(sqlUpper, "SELECT"):
		return "DQL"
	case strings.HasPrefix(sqlUpper, "GRANT"), strings.HasPrefix(sqlUpper, "REVOKE"):
		return "DCL"
	default:
		return "OTHER"
	}
}

// extractTableName 提取表名 // Logan.Li
func extractTableName(sqlUpper string) string {
	// 匹配 FROM/INTO/UPDATE/TABLE 后面的表名
	patterns := []string{
		`FROM\s+(\w+)`,
		`INTO\s+(\w+)`,
		`UPDATE\s+(\w+)`,
		`TABLE\s+(\w+)`,
		`JOIN\s+(\w+)`,
	}
	for _, p := range patterns {
		re := regexp.MustCompile(p)
		m := re.FindStringSubmatch(sqlUpper)
		if len(m) > 1 {
			return strings.ToLower(m[1])
		}
	}
	return ""
}

// analyzeRisk 分析SQL风险等级 // Logan.Li
func (h *SQLAuditHandler) analyzeRisk(sqlUpper string) (string, []string) {
	// 从数据库加载启用的规则
	var rules []models.SQLAuditRule
	h.db.Where("enabled = ?", true).Find(&rules)

	// 如果没有数据库规则，使用内置规则
	if len(rules) == 0 {
		rules = builtinRules()
	}

	var matched []string
	maxSeverity := "safe"

	for _, rule := range rules {
		if matchRule(sqlUpper, rule) {
			matched = append(matched, rule.Name)
			if severityRank(rule.Severity) > severityRank(maxSeverity) {
				maxSeverity = rule.Severity
			}
		}
	}

	return maxSeverity, matched
}

// matchRule 检查SQL是否匹配规则 // Logan.Li
func matchRule(sqlUpper string, rule models.SQLAuditRule) bool {
	// 按 category 快速匹配
	if rule.Category != "" {
		if strings.Contains(sqlUpper, strings.ToUpper(rule.Category)) {
			return true
		}
	}
	// 按 pattern 正则匹配
	if rule.Pattern != "" {
		if re, err := regexp.Compile("(?i)" + rule.Pattern); err == nil {
			if re.MatchString(sqlUpper) {
				return true
			}
		}
	}
	return false
}

// severityRank 风险等级排序 // Logan.Li
func severityRank(s string) int {
	switch s {
	case "high":
		return 4
	case "medium":
		return 3
	case "low":
		return 2
	default:
		return 1
	}
}

// builtinRules 内置审计规则 // Logan.Li
func builtinRules() []models.SQLAuditRule {
	return []models.SQLAuditRule{
		{Name: "DROP TABLE", Category: "DROP TABLE", Severity: "high", Description: "删除表操作，不可恢复"},
		{Name: "TRUNCATE TABLE", Category: "TRUNCATE", Severity: "high", Description: "清空表数据"},
		{Name: "DELETE 无 WHERE", Pattern: `DELETE\s+FROM\s+\w+\s*(?:;|$)`, Severity: "high", Description: "无条件的DELETE操作"},
		{Name: "UPDATE 无 WHERE", Pattern: `UPDATE\s+\w+\s+SET.*(?:;|$)`, Severity: "high", Description: "无条件的UPDATE操作"},
		{Name: "ALTER TABLE", Category: "ALTER", Severity: "medium", Description: "修改表结构"},
		{Name: "DROP DATABASE", Category: "DROP DATABASE", Severity: "high", Description: "删除数据库"},
		{Name: "GRANT/REVOKE", Category: "GRANT", Severity: "medium", Description: "权限变更操作"},
	}
}