package handler

import (
	"net/http"
	"strconv"

	"sql-platform/internal/model"

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

// GET /api/v1/instance-groups
// (already in ghost.go as stub, replace with real implementation)

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

// POST /api/v1/instance-groups
func CreateInstanceGroup(c *gin.Context) {
	var group model.InstanceGroup
	if err := c.ShouldBindJSON(&group); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
		return
	}
	if err := model.DB.Create(&group).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"detail": err.Error()})
		return
	}
	c.JSON(http.StatusCreated, enrichGroup(group))
}

// PUT /api/v1/instance-groups/:id
func UpdateInstanceGroup(c *gin.Context) {
	id := c.Param("id")
	gid, _ := strconv.Atoi(id)
	var group model.InstanceGroup
	if err := model.DB.First(&group, id).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"detail": "Instance group not found"})
		return
	}

	var input struct {
		Name                *string `json:"name"`
		Description         *string `json:"description"`
		DBType              *string `json:"db_type"`
		Permissions         *string `json:"permissions"`
		IsActive            *bool   `json:"is_active"`
		WorkflowID          *int    `json:"workflow_id"`
		AccessType          *string `json:"access_type"`
		AllowedDatabases    *string `json:"allowed_databases"`
		ReadonlyInstanceIDs *[]int  `json:"readonly_instance_ids"`
		WriteInstanceIDs    *[]int  `json:"write_instance_ids"`
	}
	if err := c.ShouldBindJSON(&input); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
		return
	}

	updates := map[string]interface{}{}
	if input.Name != nil {
		updates["name"] = *input.Name
	}
	if input.Description != nil {
		updates["description"] = *input.Description
	}
	if input.DBType != nil {
		updates["db_type"] = *input.DBType
	}
	if input.Permissions != nil {
		updates["permissions"] = *input.Permissions
	}
	if input.IsActive != nil {
		updates["is_active"] = *input.IsActive
	}
	if input.WorkflowID != nil {
		updates["workflow_id"] = *input.WorkflowID
	}
	if input.AccessType != nil {
		updates["access_type"] = *input.AccessType
	}
	if input.AllowedDatabases != nil {
		updates["allowed_databases"] = *input.AllowedDatabases
	}

	if len(updates) > 0 {
		if err := model.DB.Model(&group).Updates(updates).Error; err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"detail": err.Error()})
			return
		}
	}

	// Update instance members if provided
	if input.ReadonlyInstanceIDs != nil || input.WriteInstanceIDs != nil {
		// Clear all existing members for this group
		model.DB.Where("group_id = ?", gid).Delete(&model.InstanceGroupMember{})

		// Add readonly instances
		if input.ReadonlyInstanceIDs != nil {
			for _, iid := range *input.ReadonlyInstanceIDs {
				member := model.InstanceGroupMember{
					GroupID:    gid,
					InstanceID: iid,
					AccessType: "readonly",
				}
				model.DB.Create(&member)
			}
		}

		// Add write instances
		if input.WriteInstanceIDs != nil {
			for _, iid := range *input.WriteInstanceIDs {
				member := model.InstanceGroupMember{
					GroupID:    gid,
					InstanceID: iid,
					AccessType: "write",
				}
				model.DB.Create(&member)
			}
		}
	}

	model.DB.First(&group, id)
	c.JSON(http.StatusOK, enrichGroup(group))
}

// DELETE /api/v1/instance-groups/:id
func DeleteInstanceGroup(c *gin.Context) {
	id := c.Param("id")
	if err := model.DB.Delete(&model.InstanceGroup{}, id).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"detail": err.Error()})
		return
	}
	// also clean up members
	model.DB.Where("group_id = ?", id).Delete(&model.InstanceGroupMember{})
	c.JSON(http.StatusOK, gin.H{"message": "Instance group deleted"})
}

// POST /api/v1/instance-groups/:id/instances
func AssignGroupInstances(c *gin.Context) {
	groupID, _ := strconv.Atoi(c.Param("id"))
	var input struct {
		InstanceIDs []int  `json:"instance_ids"`
		AccessType  string `json:"access_type"`
	}
	if err := c.ShouldBindJSON(&input); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
		return
	}
	if input.AccessType == "" {
		input.AccessType = "readonly"
	}

	for _, iid := range input.InstanceIDs {
		member := model.InstanceGroupMember{
			GroupID:    groupID,
			InstanceID: iid,
			AccessType: input.AccessType,
		}
		model.DB.Where("group_id = ? AND instance_id = ? AND access_type = ?",
			groupID, iid, input.AccessType).FirstOrCreate(&member)
	}
	c.JSON(http.StatusOK, gin.H{"message": "Instances assigned"})
}

// DELETE /api/v1/instance-groups/:id/instances/:instanceId
func RemoveGroupInstance(c *gin.Context) {
	groupID := c.Param("id")
	instanceID := c.Param("instanceId")
	accessType := c.Query("access_type")

	query := model.DB.Where("group_id = ? AND instance_id = ?", groupID, instanceID)
	if accessType != "" {
		query = query.Where("access_type = ?", accessType)
	}
	query.Delete(&model.InstanceGroupMember{})
	c.JSON(http.StatusOK, gin.H{"message": "Instance removed from group"})
}

// GET /api/v1/instance-groups/:id/users
func ListGroupUsers(c *gin.Context) {
	groupID := c.Param("id")
	var userGroups []model.UserGroup
	model.DB.Where("group_id = ?", groupID).Find(&userGroups)
	c.JSON(http.StatusOK, userGroups)
}

// POST /api/v1/instance-groups/:id/users
func AssignGroupUsers(c *gin.Context) {
	groupID, _ := strconv.Atoi(c.Param("id"))
	var input struct {
		UserIDs     []int    `json:"user_ids"`
		Permissions []string `json:"permissions"`
	}
	if err := c.ShouldBindJSON(&input); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
		return
	}

	// delete existing
	model.DB.Where("group_id = ?", groupID).Delete(&model.UserGroup{})

	perms := ""
	if len(input.Permissions) > 0 {
		// store as JSON array string
		import_json_str := "["
		for i, p := range input.Permissions {
			if i > 0 {
				import_json_str += ","
			}
			import_json_str += `"` + p + `"`
		}
		import_json_str += "]"
		perms = import_json_str
	}

	for _, uid := range input.UserIDs {
		ug := model.UserGroup{UserID: uid, GroupID: groupID}
		if perms != "" {
			ug.Permissions = &perms
		}
		model.DB.Create(&ug)
	}
	c.JSON(http.StatusOK, gin.H{"message": "Users assigned"})
}

// PUT /api/v1/instance-groups/users/:userId/groups
func UpdateUserGroups(c *gin.Context) {
	userID := c.Param("userId")
	var input struct {
		GroupIDs []int `json:"group_ids"`
	}
	if err := c.ShouldBindJSON(&input); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
		return
	}

	uid, _ := strconv.Atoi(userID)
	model.DB.Where("user_id = ?", uid).Delete(&model.UserGroup{})
	for _, gid := range input.GroupIDs {
		model.DB.Create(&model.UserGroup{UserID: uid, GroupID: gid})
	}
	c.JSON(http.StatusOK, gin.H{"message": "User groups updated"})
}

// enrichGroup adds computed counts to InstanceGroup response
func enrichGroup(group model.InstanceGroup) gin.H {
	gid := group.ID

	var readonlyCount, writeCount, userCount int64
	var readonlyMembers, writeMembers []model.InstanceGroupMember

	model.DB.Where("group_id = ? AND access_type IN ?", gid, []string{"readonly", "readwrite"}).Find(&readonlyMembers)
	readonlyCount = int64(len(readonlyMembers))

	model.DB.Where("group_id = ? AND access_type IN ?", gid, []string{"write", "readwrite"}).Find(&writeMembers)
	writeCount = int64(len(writeMembers))

	model.DB.Model(&model.UserGroup{}).Where("group_id = ?", gid).Count(&userCount)

	// collect instance details
	allInstanceIDs := []int{}
	for _, m := range readonlyMembers {
		allInstanceIDs = append(allInstanceIDs, m.InstanceID)
	}
	for _, m := range writeMembers {
		allInstanceIDs = append(allInstanceIDs, m.InstanceID)
	}

	// unique
	seen := map[int]bool{}
	uniqueIDs := []int{}
	for _, id := range allInstanceIDs {
		if !seen[id] {
			seen[id] = true
			uniqueIDs = append(uniqueIDs, id)
		}
	}

	var instances []model.Instance
	if len(uniqueIDs) > 0 {
		model.DB.Where("id IN ?", uniqueIDs).Find(&instances)
	}
	for i := range instances {
		instances[i].Password = "******"
	}

	return gin.H{
		"id":                      group.ID,
		"name":                    group.Name,
		"description":             group.Description,
		"db_type":                 group.DBType,
		"permissions":             group.Permissions,
		"is_active":               group.IsActive,
		"created_at":              group.CreatedAt,
		"updated_at":              group.UpdatedAt,
		"workflow_id":             group.WorkflowID,
		"access_type":             group.AccessType,
		"allowed_databases":       group.AllowedDatabases,
		"readonly_instance_count": readonlyCount,
		"write_instance_count":    writeCount,
		"user_count":              userCount,
		"readonly_instance_ids":   collectInstanceIDs(readonlyMembers),
		"write_instance_ids":      collectInstanceIDs(writeMembers),
	}
}

func collectInstanceIDs(members []model.InstanceGroupMember) []int {
	ids := []int{}
	seen := map[int]bool{}
	for _, m := range members {
		if !seen[m.InstanceID] {
			seen[m.InstanceID] = true
			ids = append(ids, m.InstanceID)
		}
	}
	return ids
}