package acquire

import (
	"context"
	"errors"
	"fmt"
	"net/url"
	"strings"

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

	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
)

// ErrNotFound is a code with no row.
var ErrNotFound = errors.New("no such service")

// ErrTooMany is a twenty-first row of one protocol.
var ErrTooMany = errors.New("there are already twenty of these")

// InvalidError is a setting the operator has to change, in words for the
// settings card.
type InvalidError struct {
	Field   string
	Message string
}

func (e *InvalidError) Error() string { return e.Message }

func invalid(field, msg string) error { return &InvalidError{Field: field, Message: msg} }

// maxPerProtocol bounds the codes tried for a new row. Nobody runs twenty
// Prowlarrs; the bound keeps a loop over a full table finite.
const maxPerProtocol = 20

// Store reads and writes acquisition_services.
type Store struct {
	pool *pgxpool.Pool
}

// NewStore returns a Store over pool.
func NewStore(pool *pgxpool.Pool) *Store { return &Store{pool: pool} }

// List returns every row without its secrets.
func (s *Store) List(ctx context.Context) ([]dbq.ListAcquisitionServicesRow, error) {
	return dbq.New(s.pool).ListAcquisitionServices(ctx)
}

// Get returns one row, secrets included: for building a client only.
func (s *Store) Get(ctx context.Context, code string) (dbq.AcquisitionService, error) {
	row, err := dbq.New(s.pool).GetAcquisitionService(ctx, code)
	if errors.Is(err, pgx.ErrNoRows) {
		return row, ErrNotFound
	}
	return row, err
}

// Create adds a row of protocol, switched off and with no address. Its code
// is the protocol for the first, then protocol-2, protocol-3.
func (s *Store) Create(ctx context.Context, protocol string) (dbq.AcquisitionService, error) {
	a, ok := catalogue[protocol]
	if !ok {
		return dbq.AcquisitionService{}, invalid("protocol", "One of prowlarr, torznab, qbittorrent, exchange.")
	}
	q := dbq.New(s.pool)
	for n := 1; n <= maxPerProtocol; n++ {
		code, label := protocol, a.label
		if n > 1 {
			code, label = fmt.Sprintf("%s-%d", protocol, n), fmt.Sprintf("%s %d", a.label, n)
		}
		row, err := q.CreateAcquisitionService(ctx, dbq.CreateAcquisitionServiceParams{
			Code: code, Kind: a.kind, Protocol: protocol, Label: label,
			Category: a.category, TimeoutMs: a.timeoutMs, SearchesPerHour: a.perHour,
		})
		if errors.Is(err, pgx.ErrNoRows) {
			continue
		}
		return row, err
	}
	return dbq.AcquisitionService{}, ErrTooMany
}

// Update is everything on the settings form except the credentials.
type Update struct {
	Label            string
	Enabled          bool
	BaseURL          string
	Username         string
	Category         string
	TimeoutMs        int32
	ServesSearch     bool
	ServesDownloads  bool
	ServesEnrichment bool
	LocalPath        string
	RemotePath       string
	SearchesPerHour  int32
}

// Save validates u and writes it to code's row.
func (s *Store) Save(ctx context.Context, code string, u Update) (dbq.AcquisitionService, error) {
	u.Label = strings.TrimSpace(u.Label)
	u.BaseURL = strings.TrimSpace(u.BaseURL)
	u.Username = strings.TrimSpace(u.Username)
	u.Category = strings.TrimSpace(u.Category)
	u.LocalPath = strings.TrimSpace(u.LocalPath)
	u.RemotePath = strings.TrimSpace(u.RemotePath)
	if err := u.validate(); err != nil {
		return dbq.AcquisitionService{}, err
	}
	row, err := dbq.New(s.pool).UpdateAcquisitionService(ctx, dbq.UpdateAcquisitionServiceParams{
		Code: code, Label: u.Label, Enabled: u.Enabled, BaseUrl: u.BaseURL,
		Username: u.Username, Category: u.Category, TimeoutMs: u.TimeoutMs,
		ServesSearch: u.ServesSearch, ServesDownloads: u.ServesDownloads,
		ServesEnrichment: u.ServesEnrichment, LocalPath: u.LocalPath,
		RemotePath: u.RemotePath, SearchesPerHour: u.SearchesPerHour,
	})
	if errors.Is(err, pgx.ErrNoRows) {
		return row, ErrNotFound
	}
	return row, err
}

// validate mirrors the table's CHECKs, so a bad value is named in the card's
// own terms before Postgres refuses it.
func (u Update) validate() error {
	if u.Label == "" {
		return invalid("label", "Name: give it a name.")
	}
	if u.Enabled && u.BaseURL == "" {
		return invalid("base_url", "Address: give the address before switching this on.")
	}
	if u.BaseURL != "" {
		parsed, err := url.Parse(u.BaseURL)
		if err != nil || (parsed.Scheme != "http" && parsed.Scheme != "https") || parsed.Host == "" {
			return invalid("base_url", "Address: start with http:// or https://.")
		}
	}
	if u.TimeoutMs < 1000 || u.TimeoutMs > 300000 {
		return invalid("timeout_ms", "Give up after: between 1000 and 300000 milliseconds.")
	}
	if !strings.HasPrefix(u.LocalPath, "/") {
		return invalid("local_path", "Downloads folder as Minstrel sees it: a full path, starting with /.")
	}
	if u.RemotePath != "" && !strings.HasPrefix(u.RemotePath, "/") {
		return invalid("remote_path", "Downloads folder as the client sees it: a full path starting with /, or empty when it is the same path.")
	}
	if u.SearchesPerHour < 0 || u.SearchesPerHour > 3600 {
		return invalid("searches_per_hour", "Searches per hour: between 0 and 3600. 0 means no limit.")
	}
	return nil
}

// Delete removes code's row.
func (s *Store) Delete(ctx context.Context, code string) error {
	n, err := dbq.New(s.pool).DeleteAcquisitionService(ctx, code)
	if err != nil {
		return err
	}
	if n == 0 {
		return ErrNotFound
	}
	return nil
}

// SetAPIKey stores a key, trimmed; empty clears it.
func (s *Store) SetAPIKey(ctx context.Context, code, key string) error {
	n, err := dbq.New(s.pool).SetAcquisitionServiceAPIKey(ctx, dbq.SetAcquisitionServiceAPIKeyParams{
		Code: code, ApiKey: strings.TrimSpace(key),
	})
	return affected(n, err)
}

// SetPassword stores a password as typed (spaces are part of a password);
// empty clears it.
func (s *Store) SetPassword(ctx context.Context, code, password string) error {
	n, err := dbq.New(s.pool).SetAcquisitionServicePassword(ctx, dbq.SetAcquisitionServicePasswordParams{
		Code: code, Password: password,
	})
	return affected(n, err)
}

func affected(n int64, err error) error {
	if err != nil {
		return err
	}
	if n == 0 {
		return ErrNotFound
	}
	return nil
}