package wanted

import (
	"context"
	"errors"
	"fmt"
	"slices"
	"strings"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgconn"
	"github.com/jackc/pgx/v5/pgtype"

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

// PrimaryTypes and SecondaryTypes are MusicBrainz's release-group types, in
// the order the profile editor lists them.
var (
	PrimaryTypes   = []string{"Album", "EP", "Single", "Broadcast", "Other"}
	SecondaryTypes = []string{
		"Compilation", "Live", "Remix", "Soundtrack", "DJ-mix", "Mixtape/Street",
		"Demo", "Spokenword", "Interview", "Audiobook", "Audio drama", "Field recording",
	}
)

// Profile errors, which the API answers as 400 or 409.
var (
	ErrProfileInvalid  = errors.New("wanted: profile is not valid")
	ErrProfileNotFound = errors.New("wanted: no such profile")
	ErrProfileInUse    = errors.New("wanted: profile is in use")
	ErrProfileDefault  = errors.New("wanted: the default profile cannot be deleted")
	ErrProfileNameUsed = errors.New("wanted: a profile already has that name")
)

// Passes reports whether a release group of the given types is one a follow
// on profile p wants: its primary type is listed, and every secondary type
// it carries is allowed. A group with no secondary type is a studio release,
// which every profile passes on its primary type alone.
func Passes(p dbq.ReleaseTypeProfile, primary string, secondary []string) bool {
	if !containsFold(p.PrimaryTypes, primary) {
		return false
	}
	for _, s := range secondary {
		if !containsFold(p.SecondaryTypes, s) {
			return false
		}
	}
	return true
}

func containsFold(list []string, s string) bool {
	return slices.ContainsFunc(list, func(v string) bool { return strings.EqualFold(v, s) })
}

// ProfileInput is a profile as the editor sends it.
type ProfileInput struct {
	Name           string
	PrimaryTypes   []string
	SecondaryTypes []string
	IsDefault      bool
}

// normalize checks the input against MusicBrainz's types and returns it with
// each type in MusicBrainz's spelling and the editor's order.
func (in ProfileInput) normalize() (ProfileInput, error) {
	in.Name = strings.TrimSpace(in.Name)
	if in.Name == "" || len(in.Name) > 60 {
		return in, fmt.Errorf("%w: a name of 1 to 60 characters is required", ErrProfileInvalid)
	}
	primary, err := pick(PrimaryTypes, in.PrimaryTypes)
	if err != nil {
		return in, err
	}
	if len(primary) == 0 {
		return in, fmt.Errorf("%w: choose at least one kind of release", ErrProfileInvalid)
	}
	secondary, err := pick(SecondaryTypes, in.SecondaryTypes)
	if err != nil {
		return in, err
	}
	in.PrimaryTypes, in.SecondaryTypes = primary, secondary
	return in, nil
}

func pick(known, chosen []string) ([]string, error) {
	for _, c := range chosen {
		if !containsFold(known, c) {
			return nil, fmt.Errorf("%w: %q is not a MusicBrainz release type", ErrProfileInvalid, c)
		}
	}
	out := []string{}
	for _, k := range known {
		if containsFold(chosen, k) {
			out = append(out, k)
		}
	}
	return out, nil
}

// CreateProfile adds a profile, making it the default when asked.
func (s *Service) CreateProfile(ctx context.Context, in ProfileInput) (dbq.ReleaseTypeProfile, error) {
	in, err := in.normalize()
	if err != nil {
		return dbq.ReleaseTypeProfile{}, err
	}
	var out dbq.ReleaseTypeProfile
	err = pgx.BeginFunc(ctx, s.pool, func(tx pgx.Tx) error {
		q := dbq.New(tx)
		p, err := q.CreateReleaseTypeProfile(ctx, dbq.CreateReleaseTypeProfileParams{
			Name: in.Name, PrimaryTypes: in.PrimaryTypes, SecondaryTypes: in.SecondaryTypes,
		})
		if err != nil {
			return nameErr(err)
		}
		if in.IsDefault {
			if err := makeDefault(ctx, q, p.ID); err != nil {
				return err
			}
			p.IsDefault = true
		}
		out = p
		return nil
	})
	return out, err
}

// UpdateProfile replaces a profile's name and types. IsDefault only ever
// moves the default here; to unset it, make another profile the default.
func (s *Service) UpdateProfile(ctx context.Context, id pgtype.UUID, in ProfileInput) (dbq.ReleaseTypeProfile, error) {
	in, err := in.normalize()
	if err != nil {
		return dbq.ReleaseTypeProfile{}, err
	}
	var out dbq.ReleaseTypeProfile
	err = pgx.BeginFunc(ctx, s.pool, func(tx pgx.Tx) error {
		q := dbq.New(tx)
		p, err := q.UpdateReleaseTypeProfile(ctx, dbq.UpdateReleaseTypeProfileParams{
			ID: id, Name: in.Name, PrimaryTypes: in.PrimaryTypes, SecondaryTypes: in.SecondaryTypes,
		})
		if errors.Is(err, pgx.ErrNoRows) {
			return ErrProfileNotFound
		}
		if err != nil {
			return nameErr(err)
		}
		if in.IsDefault && !p.IsDefault {
			if err := makeDefault(ctx, q, p.ID); err != nil {
				return err
			}
			p.IsDefault = true
		}
		out = p
		return nil
	})
	return out, err
}

func makeDefault(ctx context.Context, q *dbq.Queries, id pgtype.UUID) error {
	if err := q.ClearDefaultReleaseTypeProfile(ctx); err != nil {
		return fmt.Errorf("wanted: clear default: %w", err)
	}
	if _, err := q.SetDefaultReleaseTypeProfile(ctx, id); err != nil {
		return fmt.Errorf("wanted: set default: %w", err)
	}
	return nil
}

// DeleteProfile removes a profile no follow uses. The default stays.
func (s *Service) DeleteProfile(ctx context.Context, id pgtype.UUID) error {
	q := dbq.New(s.pool)
	p, err := q.GetReleaseTypeProfile(ctx, id)
	if errors.Is(err, pgx.ErrNoRows) {
		return ErrProfileNotFound
	}
	if err != nil {
		return fmt.Errorf("wanted: read profile: %w", err)
	}
	if p.IsDefault {
		return ErrProfileDefault
	}
	if _, err := q.DeleteReleaseTypeProfile(ctx, id); err != nil {
		var pgErr *pgconn.PgError
		if errors.As(err, &pgErr) && pgErr.Code == "23503" {
			return ErrProfileInUse
		}
		return fmt.Errorf("wanted: delete profile: %w", err)
	}
	return nil
}

// profileOrDefault reads the profile a follow names; the zero id means the
// default.
func profileOrDefault(ctx context.Context, q *dbq.Queries, id pgtype.UUID) (dbq.ReleaseTypeProfile, error) {
	var (
		p   dbq.ReleaseTypeProfile
		err error
	)
	if id.Valid {
		p, err = q.GetReleaseTypeProfile(ctx, id)
	} else {
		p, err = q.GetDefaultReleaseTypeProfile(ctx)
	}
	if errors.Is(err, pgx.ErrNoRows) {
		return p, ErrProfileNotFound
	}
	if err != nil {
		return p, fmt.Errorf("wanted: read profile: %w", err)
	}
	return p, nil
}

func nameErr(err error) error {
	var pgErr *pgconn.PgError
	if errors.As(err, &pgErr) && pgErr.Code == "23505" {
		return ErrProfileNameUsed
	}
	return fmt.Errorf("wanted: save profile: %w", err)
}