package handler

import (
	"net/http"
	"strconv"

	"sql-platform/internal/middleware"
	"sql-platform/internal/model"

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

// GET /api/v1/instances
func ListInstances(c *gin.Context) {
	userID, _, role := middleware.GetCurrentUser(c)
	
	var instances []model.Instance
	query := model.DB.Order("id")
	
	// developer only sees instances in their groups
	if role == "developer" {
		var groupIDs []int
		model.DB.Model(&model.UserGroup{}).Where("user_id = ?", userID).Pluck("group_id", &groupIDs)
		if len(groupIDs) > 0 {
			var instanceIDs []int
			model.DB.Model(&model.InstanceGroupMember{}).Where("group_id IN ?", groupIDs).Pluck("instance_id", &instanceIDs)
			if len(instanceIDs) > 0 {
				query = query.Where("id IN ?", instanceIDs)
			} else {
				c.JSON(http.StatusOK, []model.Instance{})
				return
			}
		}
	}
	
	if err := query.Find(&instances).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"detail": err.Error()})
		return
	}
	
	// mask passwords in response
	for i := range instances {
		instances[i].Password = ""
	}
	c.JSON(http.StatusOK, instances)
}

// GET /api/v1/instances/:id
func GetInstance(c *gin.Context) {
	id := c.Param("id")
	var instance model.Instance
	if err := model.DB.First(&instance, id).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"detail": "Instance not found"})
		return
	}
	instance.Password = "******"
	c.JSON(http.StatusOK, instance)
}

// POST /api/v1/instances
func CreateInstance(c *gin.Context) {
	var instance model.Instance
	if err := c.ShouldBindJSON(&instance); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
		return
	}
	if err := model.DB.Create(&instance).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"detail": err.Error()})
		return
	}
	// Auto-detect version and cluster_mode after creation
	go func() {
		result := testDBConnectionFull(&instance)
		updates := map[string]interface{}{}
		if result.Success && result.Version != "" {
			updates["version"] = result.Version
		}
		if result.ClusterMode {
			updates["cluster_mode"] = true
		}
		if len(updates) > 0 {
			model.DB.Model(&model.Instance{}).Where("id = ?", instance.ID).Updates(updates)
		}
	}()
	instance.Password = "******"
	c.JSON(http.StatusCreated, instance)
}

// PUT /api/v1/instances/:id
func UpdateInstance(c *gin.Context) {
	id := c.Param("id")
	var instance model.Instance
	if err := model.DB.First(&instance, id).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"detail": "Instance not found"})
		return
	}
	
	var input map[string]interface{}
	if err := c.ShouldBindJSON(&input); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
		return
	}
	
	// if password is masked, don't update it
	if pw, ok := input["password"].(string); ok && pw == "******" {
		delete(input, "password")
	}
	
	if err := model.DB.Model(&instance).Updates(input).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"detail": err.Error()})
		return
	}
	
	model.DB.First(&instance, id)
	instance.Password = "******"
	c.JSON(http.StatusOK, instance)
}

// DELETE /api/v1/instances/:id
func DeleteInstance(c *gin.Context) {
	id := c.Param("id")
	if err := model.DB.Delete(&model.Instance{}, id).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"detail": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "Instance deleted"})
}

// POST /api/v1/instances/:id/test-connection
func TestConnection(c *gin.Context) {
	id := c.Param("id")
	var instance model.Instance
	if err := model.DB.First(&instance, id).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"detail": "Instance not found"})
		return
	}
	
	result := testDBConnectionFull(&instance)
	// Update version & cluster_mode in DB if detected
	updates := map[string]interface{}{}
	if result.Success && result.Version != "" {
		updates["version"] = result.Version
	}
	if result.ClusterMode {
		updates["cluster_mode"] = true
	}
	if len(updates) > 0 {
		model.DB.Model(&model.Instance{}).Where("id = ?", instance.ID).Updates(updates)
	}
	if result.Success {
		c.JSON(http.StatusOK, gin.H{"success": true, "message": result.Message, "version": result.Version, "cluster_mode": result.ClusterMode})
	} else {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "message": result.Message})
	}
}

// GET /api/v1/instances/stats
func InstanceStats(c *gin.Context) {
	var total int64
	model.DB.Model(&model.Instance{}).Count(&total)
	
	type typeCount struct {
		DBType string `json:"db_type"`
		Count  int64  `json:"count"`
	}
	var byType []typeCount
	model.DB.Model(&model.Instance{}).Select("db_type, count(*) as count").Group("db_type").Scan(&byType)
	
	c.JSON(http.StatusOK, gin.H{
		"total":  total,
		"by_type": byType,
	})
}

// Helper: parse id param to int
func parseID(s string) (int, bool) {
	id, err := strconv.Atoi(s)
	return id, err == nil
}

// GET /api/v1/instances/:id/metrics — live metrics for an instance
func InstanceMetrics(c *gin.Context) {
	id := c.Param("id")
	var instance model.Instance
	if err := model.DB.First(&instance, id).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"detail": "Instance not found"})
		return
	}

	switch instance.DBType {
	case "redis":
		metrics := getRedisMetrics(&instance)
		c.JSON(http.StatusOK, metrics)
	default:
		// For MySQL/PG: return basic status
		c.JSON(http.StatusOK, gin.H{
			"status":  "online",
			"version": instance.Version,
		})
	}
}