package models

import (
	"time"

	"gorm.io/gorm"
)

type Story struct {
	ID                 uint      `json:"id" gorm:"primaryKey"`
	EpicID             *uint     `json:"epic_id"`
	ProjectID          uint      `json:"project_id"`
	Title              string    `json:"title" gorm:"not null"`
	Description        string    `json:"description"`
	AcceptanceCriteria string    `json:"acceptance_criteria"`
	Status             string    `json:"status" gorm:"default:'backlog'"`
	Priority           string    `json:"priority" gorm:"default:'medium'"`
	StoryPoints        *int      `json:"story_points"`
	AssigneeID         *uint     `json:"assignee_id"`
	ReporterID         uint      `json:"reporter_id"`
	SprintID           *uint     `json:"sprint_id"`
	EstimatedHours     *float64  `json:"estimated_hours"`
	ActualHours        float64   `json:"actual_hours" gorm:"default:0"`
	Epic               *Epic     `json:"epic" gorm:"foreignKey:EpicID"`
	Project            Project   `json:"project" gorm:"foreignKey:ProjectID"`
	Assignee           *User     `json:"assignee" gorm:"foreignKey:AssigneeID"`
	Reporter           User      `json:"reporter" gorm:"foreignKey:ReporterID"`
	Sprint             *Sprint   `json:"sprint" gorm:"foreignKey:SprintID"`
	Tasks              []Task    `json:"tasks" gorm:"foreignKey:StoryID"`
	CreatedAt          time.Time `json:"created_at"`
	UpdatedAt          time.Time `json:"updated_at"`
}

type StoryStatus string

const (
	StoryStatusBacklog    StoryStatus = "backlog"
	StoryStatusTodo       StoryStatus = "todo"
	StoryStatusInProgress StoryStatus = "in_progress"
	StoryStatusReview     StoryStatus = "review"
	StoryStatusTesting    StoryStatus = "testing"
	StoryStatusDone       StoryStatus = "done"
	StoryStatusCancelled  StoryStatus = "cancelled"
)

func (s *Story) BeforeCreate(tx *gorm.DB) error {
	return nil
}

func (s *Story) GetTasks() ([]Task, error) {
	var tasks []Task
	err := DB.Where("story_id = ?", s.ID).Preload("Assignee").Find(&tasks).Error
	return tasks, err
}

func (s *Story) UpdateProgress() error {
	var totalTasks int64
	var completedTasks int64

	err := DB.Model(&Task{}).Where("story_id = ?", s.ID).Count(&totalTasks).Error
	if err != nil {
		return err
	}

	if totalTasks == 0 {
		return nil
	}

	err = DB.Model(&Task{}).Where("story_id = ? AND status = 'done'", s.ID).Count(&completedTasks).Error
	if err != nil {
		return err
	}

	if completedTasks == totalTasks {
		s.Status = string(StoryStatusDone)
	} else if completedTasks > 0 {
		s.Status = string(StoryStatusInProgress)
	}

	return DB.Save(s).Error
}

func CreateStory(story *Story) error {
	return DB.Create(story).Error
}

func GetStoryByID(id uint) (*Story, error) {
	var story Story
	err := DB.Preload("Epic").Preload("Project").Preload("Assignee").
		Preload("Reporter").Preload("Sprint").Preload("Tasks").
		First(&story, id).Error
	return &story, err
}

func GetStoriesByProject(projectID uint) ([]Story, error) {
	var stories []Story
	err := DB.Where("project_id = ?", projectID).
		Preload("Epic").Preload("Assignee").Preload("Reporter").
		Find(&stories).Error
	return stories, err
}

func GetStoriesByEpic(epicID uint) ([]Story, error) {
	var stories []Story
	err := DB.Where("epic_id = ?", epicID).
		Preload("Assignee").Preload("Reporter").
		Find(&stories).Error
	return stories, err
}

func GetStoriesBySprint(sprintID uint) ([]Story, error) {
	var stories []Story
	err := DB.Where("sprint_id = ?", sprintID).
		Preload("Assignee").Preload("Reporter").
		Find(&stories).Error
	return stories, err
}

func UpdateStory(story *Story) error {
	return DB.Save(story).Error
}

func DeleteStory(id uint) error {
	return DB.Delete(&Story{}, id).Error
}

func ListStories(offset, limit int, filters map[string]interface{}) ([]Story, int64, error) {
	var stories []Story
	var total int64

	query := DB.Model(&Story{})
	
	for key, value := range filters {
		switch key {
		case "project_id":
			query = query.Where("project_id = ?", value)
		case "epic_id":
			query = query.Where("epic_id = ?", value)
		case "sprint_id":
			query = query.Where("sprint_id = ?", value)
		case "status":
			query = query.Where("status = ?", value)
		case "priority":
			query = query.Where("priority = ?", value)
		case "assignee_id":
			query = query.Where("assignee_id = ?", value)
		}
	}

	err := query.Count(&total).Error
	if err != nil {
		return nil, 0, err
	}

	err = query.Preload("Epic").Preload("Project").Preload("Assignee").
		Preload("Reporter").Preload("Sprint").
		Offset(offset).Limit(limit).Find(&stories).Error
	return stories, total, err
}