package service

import (
	"errors"
	"math"
	"sort"
	"strconv"
	"strings"
	"time"

	entity "gitlab.com/mbugroup/lti-api.git/internal/entities"
	repository "gitlab.com/mbugroup/lti-api.git/internal/modules/daily-checklists/repositories"
	validation "gitlab.com/mbugroup/lti-api.git/internal/modules/daily-checklists/validations"
	phaseRepo "gitlab.com/mbugroup/lti-api.git/internal/modules/master/phasess/repositories"
	"gitlab.com/mbugroup/lti-api.git/internal/utils"

	"github.com/go-playground/validator/v10"
	"github.com/gofiber/fiber/v2"
	"github.com/sirupsen/logrus"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

type DailyChecklistService interface {
	GetAll(ctx *fiber.Ctx, params *validation.Query) ([]entity.DailyChecklist, int64, error)
	GetOne(ctx *fiber.Ctx, id uint) (*entity.DailyChecklist, error)
	CreateOne(ctx *fiber.Ctx, req *validation.Create) (*entity.DailyChecklist, error)
	UpdateOne(ctx *fiber.Ctx, req *validation.Update, id uint) (*entity.DailyChecklist, error)
	DeleteOne(ctx *fiber.Ctx, id uint) error
	AssignPhases(ctx *fiber.Ctx, id uint, req *validation.AssignPhases) error
	AssignTasks(ctx *fiber.Ctx, id uint, req *validation.AssignTask) error
	RemoveAssignment(ctx *fiber.Ctx, id uint, employeeID uint) error
	GetTasks(ctx *fiber.Ctx, checklistID uint) ([]entity.DailyChecklistActivityTask, error)
	UpdateAssignment(ctx *fiber.Ctx, req *validation.UpdateAssignment) error
	GetChecklistPhaseIDs(ctx *fiber.Ctx, checklistID uint) ([]uint, error)
	GetDetail(ctx *fiber.Ctx, id uint) (*DailyChecklistDetail, error)
	GetSummary(ctx *fiber.Ctx, params *validation.SummaryQuery) ([]DailyChecklistSummary, error)
}

type dailyChecklistService struct {
	Log        *logrus.Logger
	Validate   *validator.Validate
	Repository repository.DailyChecklistRepository
	PhaseRepo  phaseRepo.PhasesRepository
}

type DailyChecklistDetail struct {
	Checklist         entity.DailyChecklist
	Phases            []entity.DailyChecklistPhase
	Tasks             []entity.DailyChecklistActivityTask
	AssignedEmployees []entity.Employee
	TotalActivities   int
	Progress          float64
}

type DailyChecklistSummary struct {
	EmployeeID     uint
	EmployeeName   string
	KandangID      uint
	KandangName    string
	TotalActivity  int
	ActivityDone   int
	ActivityLeft   int
	CompletionRate int
	LastActivity   *time.Time
}

func NewDailyChecklistService(repo repository.DailyChecklistRepository, phaseRepo phaseRepo.PhasesRepository, validate *validator.Validate) DailyChecklistService {
	return &dailyChecklistService{
		Log:        utils.Log,
		Validate:   validate,
		Repository: repo,
		PhaseRepo:  phaseRepo,
	}
}

func (s dailyChecklistService) withRelations(db *gorm.DB) *gorm.DB {
	return db.Preload("Kandang")
}

func (s dailyChecklistService) GetAll(c *fiber.Ctx, params *validation.Query) ([]entity.DailyChecklist, int64, error) {
	if err := s.Validate.Struct(params); err != nil {
		return nil, 0, err
	}

	offset := (params.Page - 1) * params.Limit

	dailyChecklists, total, err := s.Repository.GetAll(c.Context(), offset, params.Limit, func(db *gorm.DB) *gorm.DB {
		db = s.withRelations(db)
		if params.Search != "" {
			return db.Where("name LIKE ?", "%"+params.Search+"%")
		}
		return db.Order("created_at DESC").Order("updated_at DESC")
	})

	if err != nil {
		s.Log.Errorf("Failed to get dailyChecklists: %+v", err)
		return nil, 0, err
	}
	return dailyChecklists, total, nil
}

func (s dailyChecklistService) GetOne(c *fiber.Ctx, id uint) (*entity.DailyChecklist, error) {
	dailyChecklist, err := s.Repository.GetByID(c.Context(), id, s.withRelations)
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, fiber.NewError(fiber.StatusNotFound, "DailyChecklist not found")
	}
	if err != nil {
		s.Log.Errorf("Failed get dailyChecklist by id: %+v", err)
		return nil, err
	}
	return dailyChecklist, nil
}

func (s dailyChecklistService) GetDetail(c *fiber.Ctx, id uint) (*DailyChecklistDetail, error) {
	checklist, err := s.GetOne(c, id)
	if err != nil {
		return nil, err
	}

	db := s.Repository.DB().WithContext(c.Context())

	var phases []entity.DailyChecklistPhase
	if err := db.
		Where("checklist_id = ?", id).
		Preload("Phase", func(tx *gorm.DB) *gorm.DB {
			return tx.Preload("Activities")
		}).
		Order("created_at ASC").
		Find(&phases).Error; err != nil {
		s.Log.Errorf("Failed to get phases for daily checklist %d: %+v", id, err)
		return nil, err
	}

	var tasks []entity.DailyChecklistActivityTask
	if err := db.
		Where("checklist_id = ?", id).
		Preload("Phase").
		Preload("PhaseActivity").
		Preload("Assignments", func(tx *gorm.DB) *gorm.DB {
			return tx.Preload("Employee")
		}).
		Order("created_at ASC").
		Find(&tasks).Error; err != nil {
		s.Log.Errorf("Failed to get tasks for daily checklist %d: %+v", id, err)
		return nil, err
	}

	assignedEmployees := collectAssignedEmployees(tasks)

	totalActivities := 0
	for _, phase := range phases {
		totalActivities += len(phase.Phase.Activities)
	}

	var totalAssignments, completedAssignments int
	for _, task := range tasks {
		for _, assignment := range task.Assignments {
			totalAssignments++
			if assignment.Checked {
				completedAssignments++
			}
		}
	}

	var progress float64
	if totalAssignments > 0 {
		progress = math.Round((float64(completedAssignments) / float64(totalAssignments)) * 100)
	}

	return &DailyChecklistDetail{
		Checklist:         *checklist,
		Phases:            phases,
		Tasks:             tasks,
		AssignedEmployees: assignedEmployees,
		TotalActivities:   totalActivities,
		Progress:          progress,
	}, nil
}

func (s *dailyChecklistService) CreateOne(c *fiber.Ctx, req *validation.Create) (*entity.DailyChecklist, error) {
	if err := s.Validate.Struct(req); err != nil {
		return nil, err
	}

	date, err := time.Parse("2006-01-02", req.Date)
	if err != nil {
		return nil, fiber.NewError(fiber.StatusBadRequest, "invalid date format, use YYYY-MM-DD")
	}

	status := req.Status
	category := req.Category

	createBody := &entity.DailyChecklist{
		KandangId: req.KandangId,
		Date:      date,
		Category:  category,
		Status:    &status,
	}

	err = s.Repository.DB().WithContext(c.Context()).Clauses(clause.OnConflict{
		Columns:   []clause.Column{{Name: "date"}, {Name: "kandang_id"}, {Name: "category"}},
		DoUpdates: clause.Assignments(map[string]any{"status": status, "updated_at": time.Now()}),
	}).Create(createBody).Error
	if err != nil {
		s.Log.Errorf("Failed to upsert dailyChecklist: %+v", err)
		return nil, err
	}

	return s.GetOne(c, createBody.Id)
}

func (s dailyChecklistService) UpdateOne(c *fiber.Ctx, req *validation.Update, id uint) (*entity.DailyChecklist, error) {
	if err := s.Validate.Struct(req); err != nil {
		return nil, err
	}

	updateBody := map[string]any{
		"status": req.Status,
	}

	if req.RejectReason != nil {
		updateBody["reject_reason"] = *req.RejectReason
	}

	if err := s.Repository.PatchOne(c.Context(), id, updateBody, nil); err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, fiber.NewError(fiber.StatusNotFound, "DailyChecklist not found")
		}
		s.Log.Errorf("Failed to update dailyChecklist: %+v", err)
		return nil, err
	}

	return s.GetOne(c, id)
}

func (s dailyChecklistService) DeleteOne(c *fiber.Ctx, id uint) error {
	if err := s.Repository.DeleteOne(c.Context(), id); err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return fiber.NewError(fiber.StatusNotFound, "DailyChecklist not found")
		}
		s.Log.Errorf("Failed to delete dailyChecklist: %+v", err)
		return err
	}
	return nil
}

func (s dailyChecklistService) AssignPhases(c *fiber.Ctx, id uint, req *validation.AssignPhases) error {
	if err := s.Validate.Struct(req); err != nil {
		return err
	}

	if _, err := s.Repository.GetByID(c.Context(), id, nil); err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return fiber.NewError(fiber.StatusNotFound, "DailyChecklist not found")
		}
		return err
	}

	phaseIDs, err := parsePhaseIDs(req.PhaseIDs)
	if err != nil {
		return fiber.NewError(fiber.StatusBadRequest, err.Error())
	}

	if len(phaseIDs) > 0 {
		phases, err := s.PhaseRepo.GetByIDs(c.Context(), phaseIDs, nil)
		if err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				return fiber.NewError(fiber.StatusBadRequest, "Phase not found")
			}
			return err
		}
		if len(phases) != len(phaseIDs) {
			return fiber.NewError(fiber.StatusBadRequest, "Phase not found")
		}
	}

	db := s.Repository.DB()
	if err := db.WithContext(c.Context()).Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("checklist_id = ?", id).Delete(&entity.DailyChecklistPhase{}).Error; err != nil {
			return err
		}

		if len(phaseIDs) == 0 {
			return nil
		}

		records := make([]entity.DailyChecklistPhase, 0, len(phaseIDs))
		for _, pid := range phaseIDs {
			records = append(records, entity.DailyChecklistPhase{
				ChecklistId: id,
				PhaseId:     pid,
			})
		}

		if err := tx.Create(&records).Error; err != nil {
			return err
		}

		if err := tx.Where("checklist_id = ?", id).Delete(&entity.DailyChecklistActivityTask{}).Error; err != nil {
			return err
		}

		var activities []entity.PhaseActivity
		if err := tx.Where("phase_id IN ?", phaseIDs).Find(&activities).Error; err != nil {
			return err
		}

		activityRecords := make([]entity.DailyChecklistActivityTask, 0, len(activities))
		for _, activity := range activities {
			activityRecords = append(activityRecords, entity.DailyChecklistActivityTask{
				ChecklistId:     id,
				PhaseId:         activity.PhaseId,
				PhaseActivityId: activity.Id,
				TimeType:        activity.TimeType,
			})
		}

		if len(activityRecords) == 0 {
			return nil
		}

		return tx.Create(&activityRecords).Error
	}); err != nil {
		s.Log.Errorf("Failed to assign phases to daily checklist: %+v", err)
		return err
	}

	return nil
}

func (s dailyChecklistService) RemoveAssignment(c *fiber.Ctx, id uint, employeeID uint) error {
	if _, err := s.Repository.GetByID(c.Context(), id, nil); err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return fiber.NewError(fiber.StatusNotFound, "DailyChecklist not found")
		}
		return err
	}

	if employeeID == 0 {
		return fiber.NewError(fiber.StatusBadRequest, "Invalid employee id")
	}

	db := s.Repository.DB()
	if err := db.WithContext(c.Context()).Transaction(func(tx *gorm.DB) error {
		var tasks []entity.DailyChecklistActivityTask
		if err := tx.Where("checklist_id = ?", id).Find(&tasks).Error; err != nil {
			return err
		}

		if len(tasks) == 0 {
			return fiber.NewError(fiber.StatusBadRequest, "No activity tasks found for this checklist")
		}

		taskIDs := collectTaskIDs(tasks)
		return tx.Where("task_id IN ? AND employee_id = ?", taskIDs, employeeID).
			Delete(&entity.DailyChecklistActivityTaskAssignment{}).Error
	}); err != nil {
		s.Log.Errorf("Failed to remove assignment: %+v", err)
		return err
	}

	return nil
}

func (s dailyChecklistService) GetTasks(c *fiber.Ctx, checklistID uint) ([]entity.DailyChecklistActivityTask, error) {
	if checklistID == 0 {
		return nil, fiber.NewError(fiber.StatusBadRequest, "checklist_id is required")
	}

	if _, err := s.Repository.GetByID(c.Context(), checklistID, nil); err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, fiber.NewError(fiber.StatusNotFound, "DailyChecklist not found")
		}
		return nil, err
	}

	var tasks []entity.DailyChecklistActivityTask
	if err := s.Repository.DB().WithContext(c.Context()).
		Where("checklist_id = ?", checklistID).
		Order("created_at ASC").
		Find(&tasks).Error; err != nil {
		s.Log.Errorf("Failed to get daily checklist tasks: %+v", err)
		return nil, err
	}

	return tasks, nil
}

func (s dailyChecklistService) GetChecklistPhaseIDs(c *fiber.Ctx, checklistID uint) ([]uint, error) {
	if checklistID == 0 {
		return nil, fiber.NewError(fiber.StatusBadRequest, "checklist_id is required")
	}

	if _, err := s.Repository.GetByID(c.Context(), checklistID, nil); err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, fiber.NewError(fiber.StatusNotFound, "DailyChecklist not found")
		}
		return nil, err
	}

	var phases []entity.DailyChecklistPhase
	if err := s.Repository.DB().WithContext(c.Context()).
		Where("checklist_id = ?", checklistID).
		Order("created_at ASC").
		Find(&phases).Error; err != nil {
		s.Log.Errorf("Failed to get daily checklist phases: %+v", err)
		return nil, err
	}

	phaseIDs := make([]uint, len(phases))
	for i, p := range phases {
		phaseIDs[i] = p.PhaseId
	}

	return phaseIDs, nil
}

func (s dailyChecklistService) UpdateAssignment(c *fiber.Ctx, req *validation.UpdateAssignment) error {
	if err := s.Validate.Struct(req); err != nil {
		return err
	}

	task := new(entity.DailyChecklistActivityTask)
	if err := s.Repository.DB().WithContext(c.Context()).First(task, req.TaskID).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return fiber.NewError(fiber.StatusNotFound, "Task not found")
		}
		return err
	}

	if req.EmployeeID == 0 {
		return fiber.NewError(fiber.StatusBadRequest, "Invalid employee id")
	}

	updates := map[string]any{"updated_at": time.Now()}
	if req.Checked != nil {
		updates["checked"] = *req.Checked
	}
	if req.Note != nil {
		updates["note"] = *req.Note
	}

	return s.Repository.DB().WithContext(c.Context()).Clauses(clause.OnConflict{
		Columns:   []clause.Column{{Name: "task_id"}, {Name: "employee_id"}},
		DoUpdates: clause.Assignments(updates),
	}).Create(&entity.DailyChecklistActivityTaskAssignment{
		TaskId:     req.TaskID,
		EmployeeId: req.EmployeeID,
		Checked:    req.Checked != nil && *req.Checked,
		Note:       req.Note,
	}).Error
}

func parsePhaseIDs(raw string) ([]uint, error) {
	parts := strings.Split(raw, ",")
	result := make([]uint, 0, len(parts))
	seen := make(map[uint]struct{})

	for _, part := range parts {
		value := strings.TrimSpace(part)
		if value == "" {
			continue
		}

		num, err := strconv.ParseUint(value, 10, 64)
		if err != nil {
			return nil, errors.New("invalid phase id: " + value)
		}
		u := uint(num)
		if _, ok := seen[u]; ok {
			continue
		}
		seen[u] = struct{}{}
		result = append(result, u)
	}

	return result, nil
}

func parseIDs(raw string) ([]uint, error) {
	parts := strings.Split(raw, ",")
	result := make([]uint, 0, len(parts))
	seen := make(map[uint]struct{})

	for _, part := range parts {
		value := strings.TrimSpace(part)
		if value == "" {
			continue
		}

		num, err := strconv.ParseUint(value, 10, 64)
		if err != nil {
			return nil, errors.New("invalid employee id: " + value)
		}
		u := uint(num)
		if _, ok := seen[u]; ok {
			continue
		}
		seen[u] = struct{}{}
		result = append(result, u)
	}

	return result, nil
}

func collectTaskIDs(tasks []entity.DailyChecklistActivityTask) []uint {
	result := make([]uint, len(tasks))
	for i, task := range tasks {
		result[i] = task.Id
	}
	return result
}

func collectAssignedEmployees(tasks []entity.DailyChecklistActivityTask) []entity.Employee {
	employeeMap := make(map[uint]entity.Employee)
	for _, task := range tasks {
		for _, assignment := range task.Assignments {
			if assignment.Employee.Id == 0 {
				continue
			}
			if _, exists := employeeMap[assignment.Employee.Id]; exists {
				continue
			}
			employeeMap[assignment.Employee.Id] = assignment.Employee
		}
	}

	employees := make([]entity.Employee, 0, len(employeeMap))
	for _, emp := range employeeMap {
		employees = append(employees, emp)
	}

	sort.Slice(employees, func(i, j int) bool {
		return employees[i].Id < employees[j].Id
	})

	return employees
}
func (s dailyChecklistService) AssignTasks(c *fiber.Ctx, id uint, req *validation.AssignTask) error {
	if err := s.Validate.Struct(req); err != nil {
		return err
	}

	employeeIDs, err := parseIDs(req.EmployeeIDs)
	if err != nil {
		return fiber.NewError(fiber.StatusBadRequest, err.Error())
	}

	if len(employeeIDs) == 0 {
		return fiber.NewError(fiber.StatusBadRequest, "employee_ids cannot be empty")
	}

	if _, err := s.Repository.GetByID(c.Context(), id, nil); err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return fiber.NewError(fiber.StatusNotFound, "DailyChecklist not found")
		}
		return err
	}

	db := s.Repository.DB()
	if err := db.WithContext(c.Context()).Transaction(func(tx *gorm.DB) error {
		var tasks []entity.DailyChecklistActivityTask
		if err := tx.Where("checklist_id = ?", id).Find(&tasks).Error; err != nil {
			return err
		}

		if len(tasks) == 0 {
			return fiber.NewError(fiber.StatusBadRequest, "No activity tasks found for this checklist")
		}

		assignments := make([]entity.DailyChecklistActivityTaskAssignment, 0, len(tasks)*len(employeeIDs))
		for _, task := range tasks {
			for _, empID := range employeeIDs {
				assignments = append(assignments, entity.DailyChecklistActivityTaskAssignment{
					TaskId:     task.Id,
					EmployeeId: empID,
				})
			}
		}

		return tx.Clauses(clause.OnConflict{
			Columns:   []clause.Column{{Name: "task_id"}, {Name: "employee_id"}},
			DoUpdates: clause.Assignments(map[string]any{"updated_at": time.Now()}),
		}).Create(&assignments).Error
	}); err != nil {
		s.Log.Errorf("Failed to assign tasks to daily checklist: %+v", err)
		return err
	}

	return nil
}

func (s dailyChecklistService) GetSummary(c *fiber.Ctx, params *validation.SummaryQuery) ([]DailyChecklistSummary, error) {
	if err := s.Validate.Struct(params); err != nil {
		return nil, err
	}

	dateFrom, err := time.Parse("2006-01-02", params.DateFrom)
	if err != nil {
		return nil, fiber.NewError(fiber.StatusBadRequest, "invalid date_from format, use YYYY-MM-DD")
	}

	dateTo, err := time.Parse("2006-01-02", params.DateTo)
	if err != nil {
		return nil, fiber.NewError(fiber.StatusBadRequest, "invalid date_to format, use YYYY-MM-DD")
	}

	type summaryRow struct {
		EmployeeID    uint
		EmployeeName  string
		KandangID     uint
		KandangName   string
		TotalActivity int64
		ActivityDone  int64
		ActivityLeft  int64
		LastActivity  *time.Time
	}

	rows := make([]summaryRow, 0)
	db := s.Repository.DB().WithContext(c.Context()).
		Table("daily_checklist_activity_task_assignments AS a").
		Select(`
			a.employee_id,
			e.name AS employee_name,
			d.kandang_id,
			k.name AS kandang_name,
			COUNT(*) AS total_activity,
			SUM(CASE WHEN a.checked THEN 1 ELSE 0 END) AS activity_done,
			SUM(CASE WHEN NOT a.checked THEN 1 ELSE 0 END) AS activity_left,
			MAX(a.updated_at) AS last_activity`).
		Joins("JOIN daily_checklist_activity_tasks t ON t.id = a.task_id").
		Joins("JOIN daily_checklists d ON d.id = t.checklist_id").
		Joins("JOIN kandangs k ON k.id = d.kandang_id").
		Joins("JOIN employees e ON e.id = a.employee_id").
		Where("d.date BETWEEN ? AND ?", dateFrom, dateTo)

	if params.Category != "" {
		db = db.Where("d.category = ?", params.Category)
	}

	if params.KandangID != nil {
		db = db.Where("d.kandang_id = ?", *params.KandangID)
	}

	if err := db.
		Group("a.employee_id, e.name, d.kandang_id, k.name").
		Order("e.name ASC").
		Find(&rows).Error; err != nil {
		s.Log.Errorf("Failed to get daily checklist summary: %+v", err)
		return nil, err
	}

	summaries := make([]DailyChecklistSummary, len(rows))
	for i, row := range rows {
		completionRate := 0
		if row.TotalActivity > 0 {
			completionRate = int(math.Round(float64(row.ActivityDone) / float64(row.TotalActivity) * 100))
		}

		summaries[i] = DailyChecklistSummary{
			EmployeeID:     row.EmployeeID,
			EmployeeName:   row.EmployeeName,
			KandangID:      row.KandangID,
			KandangName:    row.KandangName,
			TotalActivity:  int(row.TotalActivity),
			ActivityDone:   int(row.ActivityDone),
			ActivityLeft:   int(row.ActivityLeft),
			CompletionRate: completionRate,
			LastActivity:   row.LastActivity,
		}
	}

	return summaries, nil
}