package artifacts

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"sort"
	"strings"

	"git.wntrmute.dev/kyle/exo/core"
)

// GetTag returns the tag ID for a given tag string. Returns empty string if
// the tag doesn't exist.
func GetTag(ctx context.Context, tx *sql.Tx, tag string) (string, error) {
	var id string
	row := tx.QueryRowContext(ctx, `SELECT id FROM tags WHERE tag=?`, tag)
	if err := row.Scan(&id); err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return "", nil
		}
		return "", fmt.Errorf("artifacts: failed to look up tag %q: %w", tag, err)
	}
	return id, nil
}

// CreateTag idempotently creates a tag. If the tag already exists, this is a no-op.
func CreateTag(ctx context.Context, tx *sql.Tx, tag string) error {
	id, err := GetTag(ctx, tx, tag)
	if err != nil {
		return fmt.Errorf("artifacts: creating tag failed: %w", err)
	}
	if id != "" {
		return nil
	}

	id = core.NewUUID()
	_, err = tx.ExecContext(ctx, `INSERT INTO tags (id, tag) VALUES (?, ?)`, id, tag)
	if err != nil {
		return fmt.Errorf("artifacts: creating tag %q failed: %w", tag, err)
	}
	return nil
}

// GetAllTags returns all tag strings, sorted alphabetically.
func GetAllTags(ctx context.Context, tx *sql.Tx) ([]string, error) {
	rows, err := tx.QueryContext(ctx, `SELECT tag FROM tags`)
	if err != nil {
		return nil, fmt.Errorf("artifacts: failed to get all tags: %w", err)
	}
	defer func() { _ = rows.Close() }()

	var tags []string
	for rows.Next() {
		var tag string
		if err := rows.Scan(&tag); err != nil {
			return nil, fmt.Errorf("artifacts: failed to scan tag: %w", err)
		}
		tags = append(tags, tag)
	}
	sort.Strings(tags)
	return tags, rows.Err()
}

// GetCategory returns the category ID for a given category string.
// Returns empty string if the category doesn't exist.
func GetCategory(ctx context.Context, tx *sql.Tx, category string) (string, error) {
	var id string
	row := tx.QueryRowContext(ctx, `SELECT id FROM categories WHERE category=?`, category)
	if err := row.Scan(&id); err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return "", nil
		}
		return "", fmt.Errorf("artifacts: failed to look up category %q: %w", category, err)
	}
	return id, nil
}

// CreateCategory idempotently creates a category.
func CreateCategory(ctx context.Context, tx *sql.Tx, category string) error {
	id, err := GetCategory(ctx, tx, category)
	if err != nil {
		return fmt.Errorf("artifacts: creating category failed: %w", err)
	}
	if id != "" {
		return nil
	}

	id = core.NewUUID()
	_, err = tx.ExecContext(ctx, `INSERT INTO categories (id, category) VALUES (?, ?)`, id, category)
	if err != nil {
		return fmt.Errorf("artifacts: creating category %q failed: %w", category, err)
	}
	return nil
}

// GetAllCategories returns all category strings, sorted alphabetically.
func GetAllCategories(ctx context.Context, tx *sql.Tx) ([]string, error) {
	rows, err := tx.QueryContext(ctx, `SELECT category FROM categories`)
	if err != nil {
		return nil, fmt.Errorf("artifacts: failed to get all categories: %w", err)
	}
	defer func() { _ = rows.Close() }()

	var categories []string
	for rows.Next() {
		var category string
		if err := rows.Scan(&category); err != nil {
			return nil, fmt.Errorf("artifacts: failed to scan category: %w", err)
		}
		categories = append(categories, category)
	}
	sort.Strings(categories)
	return categories, rows.Err()
}

// tagsFromTagIDs resolves a list of tag UUIDs to their string values.
func tagsFromTagIDs(ctx context.Context, tx *sql.Tx, idList []string) (map[string]bool, error) {
	if len(idList) == 0 {
		return map[string]bool{}, nil
	}

	placeholders := make([]string, len(idList))
	args := make([]any, len(idList))
	for i, id := range idList {
		placeholders[i] = "?"
		args[i] = id
	}

	query := `SELECT tag FROM tags WHERE id IN (` + strings.Join(placeholders, ",") + `)` //nolint:gosec // placeholders are literal "?" strings, not user input
	rows, err := tx.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("artifacts: failed to resolve tag IDs: %w", err)
	}
	defer func() { _ = rows.Close() }()

	tags := map[string]bool{}
	for rows.Next() {
		var tag string
		if err := rows.Scan(&tag); err != nil {
			return nil, err
		}
		tags[tag] = true
	}
	return tags, rows.Err()
}

// categoriesFromCategoryIDs resolves a list of category UUIDs to their string values.
func categoriesFromCategoryIDs(ctx context.Context, tx *sql.Tx, idList []string) (map[string]bool, error) {
	if len(idList) == 0 {
		return map[string]bool{}, nil
	}

	placeholders := make([]string, len(idList))
	args := make([]any, len(idList))
	for i, id := range idList {
		placeholders[i] = "?"
		args[i] = id
	}

	query := `SELECT category FROM categories WHERE id IN (` + strings.Join(placeholders, ",") + `)` //nolint:gosec // placeholders are literal "?" strings, not user input
	rows, err := tx.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("artifacts: failed to resolve category IDs: %w", err)
	}
	defer func() { _ = rows.Close() }()

	categories := map[string]bool{}
	for rows.Next() {
		var category string
		if err := rows.Scan(&category); err != nil {
			return nil, err
		}
		categories[category] = true
	}
	return categories, rows.Err()
}

// GetArtifactIDsForTag returns artifact IDs that have the given tag.
func GetArtifactIDsForTag(ctx context.Context, tx *sql.Tx, tag string) ([]string, error) {
	tagID, err := GetTag(ctx, tx, tag)
	if err != nil {
		return nil, fmt.Errorf("artifacts: failed to look up tag ID: %w", err)
	}
	if tagID == "" {
		return nil, nil
	}

	rows, err := tx.QueryContext(ctx, `SELECT artifact_id FROM artifact_tags WHERE tag_id=?`, tagID)
	if err != nil {
		return nil, fmt.Errorf("artifacts: failed to get artifact IDs for tag: %w", err)
	}
	defer func() { _ = rows.Close() }()

	var ids []string
	for rows.Next() {
		var id string
		if err := rows.Scan(&id); err != nil {
			return nil, fmt.Errorf("artifacts: failed to scan artifact ID: %w", err)
		}
		ids = append(ids, id)
	}
	return ids, rows.Err()
}