package postgres

import (
	"context"
	"database/sql"
	"github.com/Masterminds/squirrel"
	"github.com/gissleh/stufflog/internal/slerrors"
	"github.com/gissleh/stufflog/models"
	"github.com/jmoiron/sqlx"
)

type taskRepository struct {
	db *sqlx.DB
}

func (r *taskRepository) Find(ctx context.Context, id string) (*models.Task, error) {
	res := models.Task{}
	err := r.db.GetContext(ctx, &res, "SELECT task.*, p.icon FROM task INNER JOIN project AS p ON task.project_id = p.project_id WHERE task_id=$1", id)
	if err != nil {
		if err == sql.ErrNoRows {
			return nil, slerrors.NotFound("Task")
		}

		return nil, err
	}

	return &res, nil
}

func (r *taskRepository) List(ctx context.Context, filter models.TaskFilter) ([]*models.Task, error) {
	tasks, _, err := r.ListWithLinks(ctx, filter)
	return tasks, err
}

func (r *taskRepository) ListWithLinks(ctx context.Context, filter models.TaskFilter) ([]*models.Task, []*models.TaskLink, error) {
	type tasksWithLinks struct {
		models.Task
		LinkedProjectID *string `db:"tl_project_id"`
	}

	sq := squirrel.Select("task.*", "tl.project_id as tl_project_id", "p.icon").From("task").PlaceholderFormat(squirrel.Dollar)
	sq = sq.Where(squirrel.Eq{"task.user_id": filter.UserID})
	if filter.Active != nil {
		if *filter.Active {
			sq = sq.Where(squirrel.Or{
				squirrel.Eq{"task.active": true},
				squirrel.Eq{"task.status_tag": []string{
					"on hold", "to do",
				}},
			})
		} else {
			sq = sq.Where(squirrel.And{
				squirrel.Eq{"task.active": false},
				squirrel.Eq{"task.status_tag": []string{
					"failed", "completed", "declined",
				}},
			})
		}
	}
	if filter.Expiring != nil {
		if *filter.Expiring {
			sq = sq.Where("task.end_time IS NOT NULL")
		} else {
			sq = sq.Where("task.end_time IS NULL")
		}
	}
	if filter.IDs != nil {
		sq = sq.Where(squirrel.Eq{"task.task_id": filter.IDs})
	}
	if filter.ItemIDs != nil {
		sq = sq.Where(squirrel.Eq{"task.item_id": filter.ItemIDs})
	}
	if filter.ProjectIDs != nil {
		sq = sq.Where(squirrel.Or{
			squirrel.Eq{"task.project_id": filter.ProjectIDs},
			squirrel.Eq{"tl.project_id": filter.ProjectIDs},
		})
	}

	sq = sq.LeftJoin("task_link AS tl ON task.task_id = tl.task_id")
	sq = sq.InnerJoin("project AS p ON task.project_id = p.project_id")
	sq = sq.OrderBy("active DESC", "status_tag ASC", "created_time")

	query, args, err := sq.ToSql()
	if err != nil {
		return nil, nil, err
	}

	rows := make([]tasksWithLinks, 0, 8)
	err = r.db.SelectContext(ctx, &rows, query, args...)
	if err != nil {
		if err == sql.ErrNoRows {
			return []*models.Task{}, []*models.TaskLink{}, nil
		}
		return nil, nil, err
	}

	added := make(map[string]bool)
	tasks := make([]*models.Task, 0, len(rows))
	links := make([]*models.TaskLink, 0, len(rows))
	for _, row := range rows {
		if row.LinkedProjectID != nil {
			links = append(links, &models.TaskLink{
				TaskID:    row.Task.ID,
				ProjectID: *row.LinkedProjectID,
			})
		}

		if !added[row.Task.ID] {
			task := row.Task
			tasks = append(tasks, &task)
			added[row.Task.ID] = true
		}
	}

	return tasks, links, nil
}

func (r *taskRepository) Insert(ctx context.Context, task models.Task) error {
	_, err := r.db.NamedExecContext(ctx, `
		INSERT INTO task (
			task_id, user_id, item_id, project_id, item_amount, name, description, active, created_time, end_time, status_tag
		) VALUES (
			:task_id, :user_id, :item_id, :project_id, :item_amount, :name, :description, :active, :created_time, :end_time, :status_tag
		)
	`, &task)
	if err != nil {
		return err
	}

	return nil
}

func (r *taskRepository) Update(ctx context.Context, task models.Task) error {
	_, err := r.db.NamedExecContext(ctx, `
		UPDATE task SET
			item_id = :item_id,
			item_amount = :item_amount,
			name = :name,
			description = :description,
			active = :active,
			end_time = :end_time,
			status_tag = :status_tag,
		    project_id = :project_id
		WHERE task_id=:task_id
	`, &task)
	if err != nil {
		return err
	}

	_, err = r.db.NamedExecContext(ctx, `UPDATE log SET item_id = :item_id WHERE task_id=:task_id`, &task)
	if err != nil {
		return err
	}

	return nil
}

func (r *taskRepository) CreateLink(ctx context.Context, link models.TaskLink) error {
	_, err := r.db.NamedExecContext(ctx, `
		INSERT INTO task_link (project_id, task_id) VALUES (:project_id, :task_id)
		ON CONFLICT DO NOTHING
	`, &link)

	return err
}

func (r *taskRepository) DeleteLink(ctx context.Context, link models.TaskLink) error {
	_, err := r.db.NamedExecContext(ctx, `
		DELETE FROM task_link WHERE task_id=:task_id AND project_id=:project_id
	`, &link)
	if err == sql.ErrNoRows {
		err = slerrors.NotFound("Link")
	}

	return err
}

func (r *taskRepository) UnlinkTask(ctx context.Context, task models.Task) error {
	_, err := r.db.ExecContext(ctx, `
		DELETE FROM task_link WHERE task_id=$1;
	`, task.ID)
	if err == sql.ErrNoRows {
		err = nil
	}

	return err
}

func (r *taskRepository) UnlinkProject(ctx context.Context, project models.Project) error {
	_, err := r.db.ExecContext(ctx, `
		DELETE FROM task_link WHERE task_id=$1;
	`, project.ID)
	if err == sql.ErrNoRows {
		err = nil
	}

	return err
}

func (r *taskRepository) Delete(ctx context.Context, task models.Task) error {
	_, err := r.db.ExecContext(ctx, `DELETE FROM task WHERE task_id=$1`, task.ID)
	if err != nil {
		if err == sql.ErrNoRows {
			return slerrors.NotFound("Task")
		}
		return err
	}

	_, err = r.db.ExecContext(ctx, `DELETE FROM task_link WHERE task_id=$1`, task.ID)
	if err != nil && err != sql.ErrNoRows {
		return err
	}

	return nil
}