package store

import (
	"context"
	"errors"

	"github.com/jackc/pgx/v5"
)

type Account struct {
	ID              int32    `json:"id"`
	Nom             string   `json:"nom"`
	Type            string   `json:"type"`
	DeviseReference string   `json:"devise_reference"`
	Plafond         *float64 `json:"plafond,omitempty"`
	MasterAccountID *int32   `json:"master_account_id,omitempty"`
	Objectif        *string  `json:"objectif,omitempty"`
	OwnerID         int32    `json:"-"`
}

type CreateAccountParams struct {
	Nom             string   `json:"nom"`
	Type            string   `json:"type"`
	DeviseReference string   `json:"devise_reference"`
	Plafond         *float64 `json:"plafond,omitempty"`
}

type CreateEnvelopeParams struct {
	Nom      string  `json:"nom"`
	Objectif *string `json:"objectif,omitempty"`
}

var ErrMasterIsSubAccount = errors.New("master account cannot itself be a sub-account")

const accountCols = `id, nom, type, devise_reference, plafond, master_account_id, objectif, owner_id`

// VerifyAccountOwner retourne pgx.ErrNoRows si le compte n'appartient pas à ownerID.
func (s *Store) VerifyAccountOwner(ctx context.Context, accountID, ownerID int32) error {
	var exists bool
	err := s.pool.QueryRow(ctx,
		`SELECT EXISTS(SELECT 1 FROM account WHERE id = $1 AND owner_id = $2)`,
		accountID, ownerID).Scan(&exists)
	if err != nil {
		return err
	}
	if !exists {
		return pgx.ErrNoRows
	}
	return nil
}

func (s *Store) ListAccounts(ctx context.Context, ownerID int32) ([]Account, error) {
	rows, err := s.pool.Query(ctx,
		`SELECT `+accountCols+` FROM account WHERE master_account_id IS NULL AND owner_id = $1 ORDER BY nom`,
		ownerID)
	if err != nil {
		return nil, err
	}
	return pgx.CollectRows(rows, pgx.RowToStructByName[Account])
}

func (s *Store) GetAccount(ctx context.Context, id int32) (Account, error) {
	rows, err := s.pool.Query(ctx,
		`SELECT `+accountCols+` FROM account WHERE id = $1`, id)
	if err != nil {
		return Account{}, err
	}
	return pgx.CollectOneRow(rows, pgx.RowToStructByName[Account])
}

func (s *Store) ListEnvelopes(ctx context.Context, masterID int32) ([]Account, error) {
	rows, err := s.pool.Query(ctx,
		`SELECT `+accountCols+` FROM account WHERE master_account_id = $1 ORDER BY nom`, masterID)
	if err != nil {
		return nil, err
	}
	return pgx.CollectRows(rows, pgx.RowToStructByName[Account])
}

type AccountWithEnvelopes struct {
	Account
	Envelopes []Account `json:"envelopes"`
}

func (s *Store) GetAccountWithEnvelopes(ctx context.Context, id int32) (AccountWithEnvelopes, error) {
	account, err := s.GetAccount(ctx, id)
	if err != nil {
		return AccountWithEnvelopes{}, err
	}
	envelopes, err := s.ListEnvelopes(ctx, id)
	if err != nil {
		return AccountWithEnvelopes{}, err
	}
	if envelopes == nil {
		envelopes = []Account{}
	}
	return AccountWithEnvelopes{Account: account, Envelopes: envelopes}, nil
}

func (s *Store) CreateAccount(ctx context.Context, p CreateAccountParams, ownerID int32) (Account, error) {
	if p.DeviseReference == "" {
		p.DeviseReference = "EUR"
	}
	rows, err := s.pool.Query(ctx,
		`INSERT INTO account (nom, type, devise_reference, plafond, owner_id)
		 VALUES ($1, $2, $3, $4, $5)
		 RETURNING `+accountCols,
		p.Nom, p.Type, p.DeviseReference, p.Plafond, ownerID)
	if err != nil {
		return Account{}, err
	}
	return pgx.CollectOneRow(rows, pgx.RowToStructByName[Account])
}

func (s *Store) CreateEnvelope(ctx context.Context, masterID int32, p CreateEnvelopeParams, ownerID int32) (Account, error) {
	master, err := s.GetAccount(ctx, masterID)
	if err != nil {
		return Account{}, err
	}
	if master.MasterAccountID != nil {
		return Account{}, ErrMasterIsSubAccount
	}
	if master.OwnerID != ownerID {
		return Account{}, pgx.ErrNoRows
	}
	rows, err := s.pool.Query(ctx,
		`INSERT INTO account (nom, type, devise_reference, master_account_id, objectif, owner_id)
		 VALUES ($1, $2, $3, $4, $5, $6)
		 RETURNING `+accountCols,
		p.Nom, master.Type, master.DeviseReference, masterID, p.Objectif, ownerID)
	if err != nil {
		return Account{}, err
	}
	return pgx.CollectOneRow(rows, pgx.RowToStructByName[Account])
}

func (s *Store) UpdateAccount(ctx context.Context, id int32, p CreateAccountParams, ownerID int32) (Account, error) {
	if p.DeviseReference == "" {
		p.DeviseReference = "EUR"
	}
	rows, err := s.pool.Query(ctx,
		`UPDATE account SET nom = $2, type = $3, devise_reference = $4, plafond = $5
		 WHERE id = $1 AND master_account_id IS NULL AND owner_id = $6
		 RETURNING `+accountCols,
		id, p.Nom, p.Type, p.DeviseReference, p.Plafond, ownerID)
	if err != nil {
		return Account{}, err
	}
	return pgx.CollectOneRow(rows, pgx.RowToStructByName[Account])
}

func (s *Store) UpdateEnvelope(ctx context.Context, id int32, p CreateEnvelopeParams, ownerID int32) (Account, error) {
	rows, err := s.pool.Query(ctx,
		`UPDATE account SET nom = $2, objectif = $3
		 WHERE id = $1 AND master_account_id IS NOT NULL AND owner_id = $4
		 RETURNING `+accountCols,
		id, p.Nom, p.Objectif, ownerID)
	if err != nil {
		return Account{}, err
	}
	return pgx.CollectOneRow(rows, pgx.RowToStructByName[Account])
}

func (s *Store) DeleteAccount(ctx context.Context, id int32, ownerID int32) error {
	_, err := s.pool.Exec(ctx, `DELETE FROM account WHERE id = $1 AND owner_id = $2`, id, ownerID)
	return err
}