package model

import (
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
)

type Recipe struct {
	Id          string `json:"id"`
	Title       string `json:"title"`
	Portions    string `json:"portions"`
	Url         string `json:"url"`
	Notes       string `json:"notes"`
	Created     string `json:"created"`
	LastChanged string `json:"last_changed"`
	Steps       []Step `json:"steps"`
	IsFavorite  bool   `json:"is_favorite"`
}

func (r Recipe) String() string {
	b, _ := json.MarshalIndent(r, "", "    ")
	return string(b)
}

func (r *Recipe) Validate() error {
	var err error

	if r.Id != "" {
		err = isPositiveOrZeroInt(r.Id)
		if err != nil {
			return fmt.Errorf("Invalid recipe ID: %w", err)
		}
	}

	if r.Title == "" {
		return fmt.Errorf("Recipes must have a title")
	}

	if r.Portions != "" {
		err = isPositiveOrZeroInt(r.Portions)
		if err != nil {
			return fmt.Errorf("Invalid recipe portions: %w", err)
		}
	}

	err = isInt(r.Created)
	if err != nil {
		return fmt.Errorf("Invalid creation time stamp: %w", err)
	}

	err = isInt(r.LastChanged)
	if err != nil {
		return fmt.Errorf("Invalid last changed time stamp: %w", err)
	}

	return nil
}

func (r *Recipe) Create(tx *sql.Tx) error {
	if r.Id != "" {
		return fmt.Errorf("Cannot create recipe if ID is given")
	}

	err := r.Validate()
	if err != nil {
		return err
	}

	cmd := `
INSERT INTO recipes
    (title, portions, url, notes, created, last_changed, is_favorite)
VALUES
    (?, ?, ?, ?, ?, ?, ?)
`

	result, err := tx.Exec(cmd, r.Title, r.Portions, r.Url, r.Notes, r.Created,
		r.LastChanged, r.IsFavorite)
	if err != nil {
		return err
	}

	id, err := result.LastInsertId()
	if err != nil {
		return err
	}

	r.Id = fmt.Sprint(id)

	for i := range r.Steps {
		r.Steps[i].Recipe = r.Id
		r.Steps[i].Index = fmt.Sprint(i)
		err = r.Steps[i].Create(tx)
		if err != nil {
			return err
		}
	}

	return nil
}

func (r *Recipe) getStepIds(tx *sql.Tx) ([]Step, error) {
	retval := make([]Step, 0)

	cmd := `
SELECT
    id
FROM
    steps
WHERE
    recipe = ?
ORDER BY
    'index' ASC
`

	rows, err := tx.Query(cmd, r.Id)
	if err != nil {
		return retval, err
	}
	defer rows.Close()

	for rows.Next() {
		s := Step{}

		err = rows.Scan(&s.Id)
		if err != nil {
			return retval, err
		}

		retval = append(retval, s)
	}

	return retval, nil
}

func (r *Recipe) Read(tx *sql.Tx) error {
	cmd := `
SELECT
    title, portions, url, notes, created, last_changed, is_favorite
FROM
    recipes
WHERE
    id = ?
`

	rows, err := tx.Query(cmd, r.Id)
	if err != nil {
		return err
	}
	defer rows.Close()

	if !rows.Next() {
		return sql.ErrNoRows
	}

	err = rows.Scan(
		&r.Title,
		&r.Portions,
		&r.Url,
		&r.Notes,
		&r.Created,
		&r.LastChanged,
		&r.IsFavorite,
	)
	if err != nil {
		return err
	}

	r.Steps, err = r.getStepIds(tx)
	if err != nil {
		return err
	}

	for i := range r.Steps {
		err = r.Steps[i].Read(tx)
		if err != nil {
			return err
		}
	}

	return r.Validate()
}

func (r *Recipe) Update(tx *sql.Tx) error {
	err := r.Validate()
	if err != nil {
		return err
	}

	oldSteps, err := r.getStepIds(tx)
	if err != nil {
		return err
	}

	for i := range oldSteps {
		err = oldSteps[i].Delete(tx)
		if err != nil {
			return err
		}
	}

	for i := range r.Steps {
		r.Steps[i].Index = fmt.Sprint(i)
		r.Steps[i].Recipe = r.Id
		err = r.Steps[i].Create(tx)
		if err != nil {
			return err
		}
	}

	cmd := `
UPDATE
    recipes
SET
    title = ?,
	portions = ?,
	url = ?,
	notes = ?,
	created = ?,
	last_changed = ?,
	is_favorite = ?
WHERE
    id = ?`

	res, err := tx.Exec(cmd, r.Title, r.Portions, r.Url, r.Notes, r.Created,
		r.LastChanged, r.IsFavorite, r.Id)
	if err != nil {
		return err
	}

	affected, err := res.RowsAffected()
	if err != nil {
		return err
	}
	if affected != 1 {
		return fmt.Errorf("Recipe update affected %d rows instead of 1", affected)
	}

	return nil
}

func (r *Recipe) Delete(tx *sql.Tx) error {
	oldSteps, err := r.getStepIds(tx)
	if err != nil {
		return err
	}

	for i := range oldSteps {
		err = oldSteps[i].Delete(tx)
		if err != nil {
			return err
		}
	}

	cmd := `
DELETE FROM
    recipes
WHERE
    id = ?
`

	result, err := tx.Exec(cmd, r.Id)
	if err != nil {
		return err
	}

	rows, err := result.RowsAffected()
	if rows != 1 {
		return errors.New("Recipe deletion did not affect exactly one row")
	}

	return nil
}

func RecipeTestData() []Recipe {
	return []Recipe{
		{
			Title:       "Pancakes",
			Portions:    "4",
			Url:         "https://example.org",
			Notes:       "Very fluffy",
			Created:     "1715957069",
			LastChanged: "1715958069",
			Steps: []Step{
				{
					Text: "Stir the dough",
					Ingredients: []Ingredient{
						{Amount: "4", Unit: "pieces", Type: "egg"},
						{Amount: "800", Unit: "g", Type: "special stuff"},
						{Amount: "0.5", Unit: "l", Type: "milk"},
					},
				},
				{Text: "Heat up pan", Ingredients: []Ingredient{}},
				{
					Text: "Make pancakes!",
					Ingredients: []Ingredient{
						{Amount: "", Unit: "", Type: "sugar"},
					},
				},
			},
			IsFavorite: true,
		},
		{
			Title:       "Burger",
			Portions:    "2",
			Url:         "https://xengineering.eu/git/ceres",
			Notes:       "Delicious!",
			Created:     "1715658069",
			LastChanged: "1715958070",
			Steps:       []Step{},
			IsFavorite:  false,
		},
	}
}