package repoService

import (
	"fmt"
	"slices"

	"git.ma-al.com/goc_marek/timetracker/app/db"
	"git.ma-al.com/goc_marek/timetracker/app/model"
	"git.ma-al.com/goc_marek/timetracker/app/utils/pagination"
	"git.ma-al.com/goc_marek/timetracker/app/utils/responseErrors"
	"gorm.io/gorm"
)

// type
type RepoService struct {
	db *gorm.DB
}

func New() *RepoService {
	return &RepoService{
		db: db.Get(),
	}
}

func (s *RepoService) GetRepositoriesForUser(userID uint) ([]uint, error) {
	var repoIDs []uint

	err := s.db.
		Table("customer_repo_accesses").
		Where("user_id = ?", userID).
		Pluck("repo_id", &repoIDs).Error
	if err != nil {
		return nil, fmt.Errorf("database error: %w", err)
	}

	return repoIDs, nil
}

func (s *RepoService) UserHasAccessToRepo(userID uint, repoID uint) (bool, error) {
	var repositories []uint
	var err error

	if repositories, err = s.GetRepositoriesForUser(userID); err != nil {
		return false, err
	}

	if !slices.Contains(repositories, repoID) {
		return false, responseErrors.ErrInvalidRepoID
	}

	return true, nil
}

// Extract all repositories assigned to user with specific id
func (s *RepoService) GetYearsForUser(userID uint, repoID uint) ([]uint, error) {
	if ok, err := s.UserHasAccessToRepo(userID, repoID); !ok {
		return nil, err
	}

	years, err := s.GetYears(repoID)
	if err != nil {
		return nil, fmt.Errorf("database error: %w", err)
	}

	return years, nil
}

func (s *RepoService) GetYears(repo uint) ([]uint, error) {

	var years []uint

	query := `
		WITH bounds AS (
		SELECT
			MIN(to_timestamp(tt.created_unix)) AS min_ts,
			MAX(to_timestamp(tt.created_unix)) AS max_ts
		FROM tracked_time tt
		JOIN issue i ON i.id = tt.issue_id
		WHERE i.repo_id = ?
			AND tt.deleted = false
		)
		SELECT
		EXTRACT(YEAR FROM y.year_start)::int AS year
		FROM bounds
		CROSS JOIN LATERAL generate_series(
		date_trunc('year', min_ts),
		date_trunc('year', max_ts),
		interval '1 year'
		) AS y(year_start)
		ORDER BY year
		`

	err := db.Get().Raw(query, repo).Find(&years).Error
	if err != nil {
		return nil, err
	}
	return years, nil
}

// Extract all repositories assigned to user with specific id
func (s *RepoService) GetQuartersForUser(userID uint, repoID uint, year uint) ([]model.QuarterData, error) {
	if ok, err := s.UserHasAccessToRepo(userID, repoID); !ok {
		return nil, err
	}

	response, err := s.GetQuarters(repoID, year)
	if err != nil {
		return nil, fmt.Errorf("database error: %w", err)
	}

	return response, nil
}

func (s *RepoService) GetQuarters(repo uint, year uint) ([]model.QuarterData, error) {
	var quarters []model.QuarterData

	query := `
		WITH quarters AS (
			SELECT
				make_date(?::int, 1, 1) + (q * interval '3 months') AS quarter_start,
				q + 1 AS quarter
			FROM generate_series(0, 3) AS q
		),
		data AS (
			SELECT
				EXTRACT(QUARTER FROM to_timestamp(tt.created_unix)) AS quarter,
				SUM(tt.time) / 3600 AS time
			FROM tracked_time tt
			JOIN issue i ON i.id = tt.issue_id
			JOIN repository r ON i.repo_id = r.id
			WHERE
				EXTRACT(YEAR FROM to_timestamp(tt.created_unix)) = ?
				AND r.id = ?
				AND tt.deleted = false
			GROUP BY EXTRACT(QUARTER FROM to_timestamp(tt.created_unix))
		)
		SELECT
			COALESCE(d.time, 0) AS time,
			CONCAT(EXTRACT(YEAR FROM q.quarter_start)::int, '_Q', q.quarter) AS quarter
		FROM quarters q
		LEFT JOIN data d ON d.quarter = q.quarter
		ORDER BY q.quarter
	`

	err := db.Get().
		Raw(query, year, year, repo).
		Find(&quarters).
		Error
	if err != nil {
		return nil, err
	}

	return quarters, nil
}

func (s *RepoService) GetIssuesForUser(
	userID uint,
	repoID uint,
	year uint,
	quarter uint,
	p pagination.Paging,
) (*pagination.Found[model.IssueTimeSummary], error) {
	if ok, err := s.UserHasAccessToRepo(userID, repoID); !ok {
		return nil, err
	}

	return s.GetIssues(repoID, year, quarter, p)
}

func (s *RepoService) GetIssues(
	repoId uint,
	year uint,
	quarter uint,
	p pagination.Paging,
) (*pagination.Found[model.IssueTimeSummary], error) {

	query := db.Get().
		Table("issue i").
		Select(`
            i.id AS issue_id,
            i.name AS issue_name,
            to_timestamp(i.created_unix) AS issue_created_at,
            ROUND(SUM(tt.time) / 3600.0, 2) AS total_hours_spent
        `).
		Joins(`JOIN tracked_time tt ON tt.issue_id = i.id`).
		Joins(`JOIN "user" u ON u.id = tt.user_id`).
		Where("i.repo_id = ?", repoId).
		Where(`
            EXTRACT(YEAR FROM to_timestamp(tt.created_unix)) = ?
            AND EXTRACT(QUARTER FROM to_timestamp(tt.created_unix)) = ?
        `, year, quarter).
		Group(`
            i.id,
            i.name,
            u.id,
            u.full_name
        `).
		Order("i.created_unix")

	result, err := pagination.Paginate[model.IssueTimeSummary](p, query)
	if err != nil {
		return nil, err
	}

	return &result, nil
}