package projects

import (
	"errors"
	"strings"

	"gorm.io/gorm"
	"senlinai-agent/backend/internal/models"
)

func (s *Service) CreateTask(ownerID uint, projectID uint, input CreateTaskInput) (*models.SenlinAgentTask, error) {
	if err := ensureProjectOwner(ownerID, projectID); err != nil {
		return nil, err
	}
	title := strings.TrimSpace(input.Title)
	if title == "" {
		return nil, errors.New("task title is required")
	}
	status := strings.TrimSpace(input.Status)
	if status == "" {
		status = "open"
	}
	tagID, err := s.findOrCreateTagID(projectID, input.Tag)
	if err != nil {
		return nil, err
	}
	task := &models.SenlinAgentTask{
		ProjectID: projectID, CreatedBy: ownerID, TagID: tagID, Title: title,
		Description: strings.TrimSpace(input.Description), Status: status, DueAt: input.DueAt,
	}
	return task, models.DBService.Create(task).Error
}

func (s *Service) UpdateTask(ownerID uint, projectID uint, taskID uint, input UpdateTaskInput) (*models.SenlinAgentTask, error) {
	if err := ensureProjectOwner(ownerID, projectID); err != nil {
		return nil, err
	}
	var task models.SenlinAgentTask
	if err := models.DBService.Where("id = ? AND project_id = ?", taskID, projectID).First(&task).Error; err != nil {
		return nil, err
	}
	nextProjectID := input.NextProjectID
	if nextProjectID == 0 {
		nextProjectID = task.ProjectID
	}
	if err := ensureProjectOwner(ownerID, nextProjectID); err != nil {
		return nil, err
	}
	title := strings.TrimSpace(input.Title)
	if title == "" {
		return nil, errors.New("task title is required")
	}
	tagID, err := s.findOrCreateTagID(nextProjectID, input.Tag)
	if err != nil {
		return nil, err
	}
	projectIdentity, err := projectIdentity(nextProjectID)
	if err != nil {
		return nil, err
	}
	tagIdentity, err := optionalTagIdentity(tagID)
	if err != nil {
		return nil, err
	}
	status := strings.TrimSpace(input.Status)
	if status == "" {
		if input.Completed {
			status = "done"
		} else {
			status = "open"
		}
	}
	task.ProjectID = nextProjectID
	task.ProjectIdentity = projectIdentity
	task.Title = title
	task.Description = strings.TrimSpace(input.Description)
	task.Status = status
	task.TagID = tagID
	task.TagIdentity = tagIdentity
	if err := models.DBService.Save(&task).Error; err != nil {
		return nil, err
	}
	return &task, nil
}

func (s *Service) CreateFileSource(ownerID uint, projectID uint, input CreateFileSourceInput) (*models.SenlinAgentSource, error) {
	if err := ensureProjectOwner(ownerID, projectID); err != nil {
		return nil, err
	}
	title := strings.TrimSpace(input.Title)
	if title == "" {
		return nil, errors.New("source title is required")
	}
	filePath := strings.TrimSpace(input.FilePath)
	if filePath == "" {
		return nil, errors.New("source file path is required")
	}
	source := &models.SenlinAgentSource{ProjectID: projectID, CreatedBy: ownerID, Kind: "file", Title: title, FilePath: filePath}
	return source, models.DBService.Create(source).Error
}

func (s *Service) CreateCronPlan(ownerID uint, projectID uint, input CreateCronPlanInput) (*models.SenlinAgentCronPlan, error) {
	if err := ensureProjectOwner(ownerID, projectID); err != nil {
		return nil, err
	}
	title := strings.TrimSpace(input.Title)
	if title == "" {
		return nil, errors.New("cron plan title is required")
	}
	schedule := strings.TrimSpace(input.Schedule)
	if schedule == "" {
		return nil, errors.New("cron schedule is required")
	}
	plan := &models.SenlinAgentCronPlan{
		ProjectID: projectID, CreatedBy: ownerID, Title: title, Schedule: schedule,
		Enabled: input.Enabled, NextRunAt: input.NextRunAt, LastResult: "Not run yet",
	}
	return plan, models.DBService.Create(plan).Error
}

func (s *Service) CreateProjectTag(ownerID uint, projectID uint, name string) (*models.SenlinAgentTag, error) {
	if err := ensureProjectOwner(ownerID, projectID); err != nil {
		return nil, err
	}
	return s.CreateTag(projectID, name)
}

func (s *Service) CreateTag(projectID uint, name string) (*models.SenlinAgentTag, error) {
	name = strings.TrimSpace(name)
	if name == "" {
		return nil, errors.New("tag name is required")
	}
	var existing models.SenlinAgentTag
	err := models.DBService.Where("project_id = ? AND name = ?", projectID, name).First(&existing).Error
	if err == nil {
		return &existing, nil
	}
	if !errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, err
	}
	tag := &models.SenlinAgentTag{ProjectID: projectID, Name: name}
	return tag, models.DBService.Create(tag).Error
}

func (s *Service) ListProjectTags(ownerID uint, projectID uint) ([]models.SenlinAgentTag, error) {
	if err := ensureProjectOwner(ownerID, projectID); err != nil {
		return nil, err
	}
	return s.ListTags(projectID)
}

func (s *Service) ListTags(projectID uint) ([]models.SenlinAgentTag, error) {
	var tags []models.SenlinAgentTag
	err := models.DBService.Where("project_id = ?", projectID).Order("name asc").Find(&tags).Error
	return tags, err
}

func (s *Service) findOrCreateTagID(projectID uint, name string) (*uint, error) {
	name = strings.TrimSpace(name)
	if name == "" {
		return nil, nil
	}
	tag, err := s.CreateTag(projectID, name)
	if err != nil {
		return nil, err
	}
	return &tag.ID, nil
}

func ensureProjectOwner(ownerID uint, projectID uint) error {
	var count int64
	if err := models.DBService.Model(&models.SenlinAgentProject{}).Where("id = ? AND owner_id = ?", projectID, ownerID).Count(&count).Error; err != nil {
		return err
	}
	if count == 0 {
		return errors.New("project not found")
	}
	return nil
}

func projectIdentity(projectID uint) (string, error) {
	var project models.SenlinAgentProject
	if err := models.DBService.Select("identity").First(&project, projectID).Error; err != nil {
		return "", err
	}
	return project.Identity, nil
}

func optionalTagIdentity(tagID *uint) (*string, error) {
	if tagID == nil {
		return nil, nil
	}
	var tag models.SenlinAgentTag
	if err := models.DBService.Select("identity").First(&tag, *tagID).Error; err != nil {
		return nil, err
	}
	return &tag.Identity, nil
}