Poll-system/app/internal/handlers/admin_team_builder.go

package handlers

import (
	"fmt"
	"net/http"
	"strconv"

	"github.com/patel-mann/poll-system/app/internal/models"
	"github.com/patel-mann/poll-system/app/internal/utils"
)


type User struct {
	ID   int
	Name string
}

type TeamLead struct {
	ID         int
	Name       string
	Volunteers []User
}

type TeamBuilderData struct {
	TeamLeads          []TeamLead
	UnassignedVolunteers []User
}



func TeamBuilderHandler(w http.ResponseWriter, r *http.Request) {
	// GET request: show team leads and unassigned volunteers
	if r.Method == http.MethodGet {
		var teamLeads []TeamLead
		var unassignedVolunteers []User

		CurrentUserID := models.GetCurrentUserID(w, r)
		username,_ := models.GetCurrentUserName(r)



		// Get all team leads (role_id = 2)
		tlRows, err := models.DB.Query(`SELECT u.user_id, u.first_name || ' ' || u.last_name AS name 
											FROM users u
											JOIN admin_volunteers x ON x.volunteer_id = u.user_id
											WHERE u.role_id = 2 AND x.admin_id = $1`, CurrentUserID)
		if err != nil {
			http.Error(w, "Error fetching team leads", http.StatusInternalServerError)
			return
		}
		defer tlRows.Close()
		for tlRows.Next() {
			var tl TeamLead
			tlRows.Scan(&tl.ID, &tl.Name)

			// Get assigned volunteers for this team lead
			vRows, _ := models.DB.Query(`SELECT u.user_id, u.first_name || ' ' || u.last_name AS name
											FROM users u
											JOIN team t ON u.user_id = t.volunteer_id
											WHERE t.team_lead_id = $1`, tl.ID)

			for vRows.Next() {
				var vol User
				vRows.Scan(&vol.ID, &vol.Name)
				tl.Volunteers = append(tl.Volunteers, vol)
			}

			teamLeads = append(teamLeads, tl)
		}

		// Get unassigned volunteers (role_id = 3)
		vRows, _ := models.DB.Query(`SELECT u.user_id, u.first_name || ' ' || u.last_name AS name
										FROM users u
										LEFT JOIN team t ON u.user_id = t.volunteer_id
										JOIN admin_volunteers x ON x.volunteer_id = u.user_id
										WHERE u.role_id = 3 AND x.admin_id = $1
										AND t.volunteer_id IS NULL`, CurrentUserID )
		for vRows.Next() {
			var vol User
			vRows.Scan(&vol.ID, &vol.Name)
			unassignedVolunteers = append(unassignedVolunteers, vol)
		}

		utils.Render(w, "volunteer/team_builder.html", map[string]interface{}{
			"Title":               "Team Builder",
			"IsAuthenticated":     true,
			"ShowAdminNav":        true,
			"TeamLeads":           teamLeads,
			"UserName": 	username,
			"UnassignedVolunteers": unassignedVolunteers,
			"ActiveSection":       "team_builder",
		})
		return
	}

	// POST request: assign volunteer to a team lead
	if r.Method == http.MethodPost {
		if err := r.ParseForm(); err != nil {
			http.Error(w, "Invalid form", http.StatusBadRequest)
			return
		}

		volunteerIDStr := r.FormValue("volunteer_id")
		teamLeadIDStr := r.FormValue("team_lead_id")

		if volunteerIDStr == "" || teamLeadIDStr == "" {
			http.Error(w, "Volunteer ID and Team Lead ID are required", http.StatusBadRequest)
			return
		}

		volunteerID, err := strconv.Atoi(volunteerIDStr)
		if err != nil {
			http.Error(w, "Invalid volunteer ID", http.StatusBadRequest)
			return
		}

		teamLeadID, err := strconv.Atoi(teamLeadIDStr)
		if err != nil {
			http.Error(w, "Invalid team lead ID", http.StatusBadRequest)
			return
		}

		// Optional: check if volunteer is already assigned
		var exists int
		err = models.DB.QueryRow(`SELECT COUNT(*) FROM team WHERE volunteer_id = $1`, volunteerID).Scan(&exists)
		if err != nil {
			http.Error(w, "Database error", http.StatusInternalServerError)
			return
		}
		if exists > 0 {
			http.Error(w, "Volunteer is already assigned to a team", http.StatusBadRequest)
			return
		}

		// Assign volunteer to team lead
		_, err = models.DB.Exec(`INSERT INTO team (volunteer_id, team_lead_id) VALUES ($1, $2)`, volunteerID, teamLeadID)
		if err != nil {
			fmt.Println(err)
			http.Error(w, "Failed to assign volunteer", http.StatusInternalServerError)
			return
		}

		http.Redirect(w, r, "/team_builder", http.StatusSeeOther)
	}
}


func RemoveVolunteerHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Redirect(w, r, "/team_builder", http.StatusSeeOther)
		return
	}

	if err := r.ParseForm(); err != nil {
		http.Error(w, "Invalid form", http.StatusBadRequest)
		return
	}

	volunteerID, err := strconv.Atoi(r.FormValue("volunteer_id"))
	if err != nil {
		http.Error(w, "Invalid volunteer ID", http.StatusBadRequest)
		return
	}

	teamLeadID, err := strconv.Atoi(r.FormValue("team_lead_id"))
	if err != nil {
		http.Error(w, "Invalid team lead ID", http.StatusBadRequest)
		return
	}

	// Remove volunteer from the team
	_, err = models.DB.Exec(`DELETE FROM team WHERE team_lead_id = $1 AND volunteer_id = $2`, teamLeadID, volunteerID)
	if err != nil {
		fmt.Println(err)
		http.Error(w, "Failed to remove volunteer from team", http.StatusInternalServerError)
		return
	}


	http.Redirect(w, r, "/team_builder", http.StatusSeeOther)
}