package service

import (
	"errors"
	"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)
}

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

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
}

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) 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 := make(map[string]any)

	if req.Name != nil {
		updateBody["name"] = *req.Name
	}

	if len(updateBody) == 0 {
		return s.GetOne(c, id)
	}

	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 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 (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
}