package creator

import (
	"context"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"net/url"
	"strings"
	"time"
	"unicode/utf8"

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

const maxRawPayloadBytes = 4 << 20

func validateHomepage(value string) error {
	parsed, err := url.Parse(strings.TrimSpace(value))
	if err != nil || (parsed.Scheme != "http" && parsed.Scheme != "https") || parsed.Host == "" || parsed.User != nil {
		return ErrInvalid
	}
	return nil
}

func validateCreatorTags(tags []string) error {
	if len(tags) > 20 {
		return ErrInvalid
	}
	for _, tag := range tags {
		if tag == "" || strings.TrimSpace(tag) != tag || !utf8.ValidString(tag) || utf8.RuneCountInString(tag) > 32 {
			return ErrInvalid
		}
	}
	return nil
}

func normalizeCompetitorInput(input CompetitorInput) (CompetitorInput, error) {
	input.Platform = strings.TrimSpace(input.Platform)
	input.PlatformAccountKey = strings.TrimSpace(input.PlatformAccountKey)
	input.UniqueID = strings.TrimSpace(input.UniqueID)
	input.Nickname = strings.TrimSpace(input.Nickname)
	input.AvatarURL = strings.TrimSpace(input.AvatarURL)
	input.HomepageURL = strings.TrimSpace(input.HomepageURL)
	if input.Tags == nil {
		input.Tags = []string{}
	}
	if !ValidatePlatform(input.Platform) || input.PlatformAccountKey == "" || input.HomepageURL == "" ||
		utf8.RuneCountInString(input.PlatformAccountKey) > 255 || utf8.RuneCountInString(input.UniqueID) > 255 || utf8.RuneCountInString(input.Nickname) > 255 ||
		utf8.RuneCountInString(input.AvatarURL) > 1000 || validateHomepage(input.HomepageURL) != nil ||
		validateCreatorTags(input.Tags) != nil {
		return CompetitorInput{}, ErrInvalid
	}
	return input, nil
}

func (s *Store) CreateCompetitor(ctx context.Context, input CompetitorInput) (Competitor, error) {
	input, err := normalizeCompetitorInput(input)
	if err != nil {
		return Competitor{}, err
	}
	id := newID("competitor")
	if _, err := s.db.ExecContext(ctx, `
		INSERT INTO creator_competitor (competitor_id, platform, platform_account_key, unique_id, nickname, avatar_url, homepage_url, tags, next_sync_at)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, now())`,
		id, input.Platform, input.PlatformAccountKey, input.UniqueID, input.Nickname, input.AvatarURL, input.HomepageURL, input.Tags); err != nil {
		return Competitor{}, databaseError(err)
	}
	return s.GetCompetitor(ctx, id)
}

// competitorColumns 是 creator_competitor 的完整列清单（含画像属性），各查询共用。
const competitorColumns = `competitor_id, platform, platform_account_key, unique_id, nickname, avatar_url, homepage_url, tags,
		enabled, follower_count, following_count, aweme_count, sync_status, sync_cursor, sync_error, sync_lease_until,
		last_sync_at, next_sync_at, created_at, updated_at`

type competitorScan struct {
	competitor                     Competitor
	tags                           pgtype.FlatArray[string]
	leaseUntil, lastSync, nextSync sql.NullTime
	follower, following, aweme     sql.NullInt64
}

func competitorScanDestinations(scan *competitorScan) []any {
	return []any{&scan.competitor.ID, &scan.competitor.Platform, &scan.competitor.PlatformAccountKey, &scan.competitor.UniqueID, &scan.competitor.Nickname,
		&scan.competitor.AvatarURL, &scan.competitor.HomepageURL, pgtype.NewMap().SQLScanner(&scan.tags), &scan.competitor.Enabled,
		&scan.follower, &scan.following, &scan.aweme, &scan.competitor.SyncStatus, &scan.competitor.SyncCursor,
		&scan.competitor.SyncError, &scan.leaseUntil, &scan.lastSync, &scan.nextSync, &scan.competitor.CreatedAt, &scan.competitor.UpdatedAt}
}

func (scan *competitorScan) materialize() Competitor {
	scan.competitor.Tags = []string(scan.tags)
	scan.competitor.FollowerCount = nullableInt64(scan.follower)
	scan.competitor.FollowingCount = nullableInt64(scan.following)
	scan.competitor.AwemeCount = nullableInt64(scan.aweme)
	scan.competitor.SyncLeaseUntil = nullableTime(scan.leaseUntil)
	scan.competitor.LastSyncAt = nullableTime(scan.lastSync)
	scan.competitor.NextSyncAt = nullableTime(scan.nextSync)
	return scan.competitor
}

func scanCompetitor(scanner interface{ Scan(...any) error }) (Competitor, error) {
	var scan competitorScan
	if err := scanner.Scan(competitorScanDestinations(&scan)...); err != nil {
		return Competitor{}, err
	}
	return scan.materialize(), nil
}

func (s *Store) GetCompetitor(ctx context.Context, id string) (Competitor, error) {
	result, err := scanCompetitor(s.db.QueryRowContext(ctx, `SELECT `+competitorColumns+` FROM creator_competitor WHERE competitor_id = $1`, id))
	return result, rowError(err)
}

// ListCompetitorsWithProfile 监控账号列表视图：账号基础信息 + 作品数/最近发布聚合统计。
func (s *Store) ListCompetitorsWithProfile(ctx context.Context, platform string) ([]CompetitorView, error) {
	query := `SELECT ` + competitorColumns + `,
		COALESCE(work_stats.work_count, 0),
		work_stats.latest_published_at
		FROM creator_competitor
		LEFT JOIN (
			SELECT w.source_id, COUNT(*) AS work_count, MAX(w.published_at) AS latest_published_at
			FROM creator_work w
			WHERE w.source_type = 'competitor'
			GROUP BY w.source_id
		) work_stats ON work_stats.source_id = creator_competitor.competitor_id`
	args := []any{}
	if platform != "" {
		if !ValidatePlatform(platform) {
			return nil, ErrInvalid
		}
		query += ` WHERE creator_competitor.platform = $1`
		args = append(args, platform)
	}
	query += ` ORDER BY creator_competitor.created_at DESC, creator_competitor.competitor_id`
	rows, err := s.db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, databaseError(err)
	}
	defer rows.Close()
	result := make([]CompetitorView, 0)
	for rows.Next() {
		item, err := scanCompetitorView(rows)
		if err != nil {
			return nil, err
		}
		result = append(result, item)
	}
	return result, rows.Err()
}

func scanCompetitorView(scanner interface{ Scan(...any) error }) (CompetitorView, error) {
	var scan competitorScan
	var latestPublished sql.NullTime
	var workCount sql.NullInt64
	destinations := append(competitorScanDestinations(&scan), &workCount, &latestPublished)
	if err := scanner.Scan(destinations...); err != nil {
		return CompetitorView{}, err
	}
	result := CompetitorView{
		Competitor:        scan.materialize(),
		WorkCount:         workCount.Int64,
		LatestPublishedAt: nullableTime(latestPublished),
	}
	return result, nil
}

// UpdateCompetitorProfile 更新监控账号画像属性（头像与粉丝/关注/作品计数）。
// 当前仅提供数据通道（字段定义与接口返回），采集侧回填由后续接入。
func (s *Store) UpdateCompetitorProfile(ctx context.Context, id, avatarURL string, followerCount, followingCount, awemeCount int64) (Competitor, error) {
	id = strings.TrimSpace(id)
	avatarURL = strings.TrimSpace(avatarURL)
	if id == "" || utf8.RuneCountInString(avatarURL) > 2000 || followerCount < 0 || followingCount < 0 || awemeCount < 0 {
		return Competitor{}, ErrInvalid
	}
	result, err := s.db.ExecContext(ctx, `
		UPDATE creator_competitor
		SET avatar_url = $2, follower_count = $3, following_count = $4, aweme_count = $5, updated_at = now()
		WHERE competitor_id = $1`, id, avatarURL, followerCount, followingCount, awemeCount)
	if err != nil {
		return Competitor{}, databaseError(err)
	}
	affected, err := result.RowsAffected()
	if err != nil {
		return Competitor{}, databaseError(err)
	}
	if affected != 1 {
		return Competitor{}, ErrNotFound
	}
	return s.GetCompetitor(ctx, id)
}

func (s *Store) UpdateCompetitorTags(ctx context.Context, id string, tags []string) (Competitor, error) {
	id = strings.TrimSpace(id)
	if id == "" || validateCreatorTags(tags) != nil {
		return Competitor{}, ErrInvalid
	}
	if tags == nil {
		tags = []string{}
	}
	result, err := s.db.ExecContext(ctx, `
		UPDATE creator_competitor SET tags = $2, updated_at = now() WHERE competitor_id = $1`, id, tags)
	if err != nil {
		return Competitor{}, databaseError(err)
	}
	affected, err := result.RowsAffected()
	if err != nil {
		return Competitor{}, databaseError(err)
	}
	if affected != 1 {
		return Competitor{}, ErrNotFound
	}
	return s.GetCompetitor(ctx, id)
}

func (s *Store) SetCompetitorEnabled(ctx context.Context, id string, enabled bool) (Competitor, error) {
	status := "paused"
	if enabled {
		status = "idle"
	}
	_, err := s.db.ExecContext(ctx, `
		UPDATE creator_competitor SET enabled = $2, sync_status = $3, sync_lease_until = NULL,
			next_sync_at = CASE WHEN $2 THEN now() ELSE NULL END, updated_at = now()
		WHERE competitor_id = $1`, id, enabled, status)
	if err != nil {
		return Competitor{}, databaseError(err)
	}
	return s.GetCompetitor(ctx, id)
}

func (s *Store) MarkCompetitorSync(ctx context.Context, id, leaseToken, status, cursor, syncError string, nextAt *time.Time) error {
	if id == "" || leaseToken == "" {
		return ErrInvalid
	}
	if status != "idle" && status != "running" && status != "paused" && status != "failed" && status != "blocked" {
		return ErrInvalid
	}
	if len(syncError) > 2000 || len(cursor) > 1000 {
		return ErrInvalid
	}
	var next any
	if nextAt != nil {
		next = nextAt.UTC()
	}
	result, err := s.db.ExecContext(ctx, `
		UPDATE creator_competitor
		SET sync_status = $3, sync_cursor = $4, sync_error = $5,
			sync_lease_token = CASE WHEN $3 = 'running' THEN $2 ELSE NULL END,
			sync_lease_until = CASE WHEN $3 = 'running' THEN now() + interval '10 minutes' ELSE NULL END,
			last_sync_at = CASE WHEN $3 IN ('idle', 'failed', 'blocked') THEN now() ELSE last_sync_at END,
			next_sync_at = $6, updated_at = now()
		WHERE competitor_id = $1 AND sync_lease_token = $2`, id, leaseToken, status, cursor, syncError, next)
	if err != nil {
		return databaseError(err)
	}
	if affected, err := result.RowsAffected(); err != nil {
		return databaseError(err)
	} else if affected != 1 {
		return ErrConflict
	}
	return nil
}

func (s *Store) ClaimCompetitorSync(ctx context.Context, id string, force bool, now time.Time) (string, bool, error) {
	if id == "" || now.IsZero() {
		return "", false, ErrInvalid
	}
	condition := `enabled AND (next_sync_at IS NULL OR next_sync_at <= $2)`
	if force {
		condition = `enabled`
	}
	token := newID("competitor-lease")
	var claimed string
	err := s.db.QueryRowContext(ctx, `UPDATE creator_competitor SET sync_status='running', sync_lease_token=$2, sync_lease_until=$3 + interval '10 minutes', sync_error='', updated_at=$3 WHERE competitor_id=$1 AND `+strings.ReplaceAll(condition, "$2", "$3")+` AND (sync_status <> 'running' OR sync_lease_until IS NULL OR sync_lease_until <= $3) RETURNING competitor_id`, id, token, now.UTC()).Scan(&claimed)
	if errors.Is(err, sql.ErrNoRows) {
		return "", false, nil
	}
	if err != nil {
		return "", false, databaseError(err)
	}
	return token, claimed != "", nil
}

// SyncClaimFailure 在 ClaimCompetitorSync 抢锁失败后调用：区分租约被占与竞品停用，
// 返回面向用户的分类错误；读不到竞品时退回通用 ErrConflict。
func (s *Store) SyncClaimFailure(ctx context.Context, id string) error {
	competitor, err := s.GetCompetitor(ctx, id)
	if err != nil {
		return ErrConflict
	}
	if !competitor.Enabled {
		return ErrSyncDisabled
	}
	return ErrSyncInProgress
}

func (s *Store) ListDueCompetitors(ctx context.Context, now time.Time) ([]Competitor, error) {
	if now.IsZero() {
		return nil, ErrInvalid
	}
	rows, err := s.db.QueryContext(ctx, `SELECT `+competitorColumns+`
		FROM creator_competitor
		WHERE enabled AND next_sync_at IS NOT NULL AND next_sync_at <= $1
			AND (sync_status <> 'running' OR sync_lease_until IS NULL OR sync_lease_until <= $1)
		ORDER BY COALESCE(next_sync_at, created_at), id`, now.UTC())
	if err != nil {
		return nil, databaseError(err)
	}
	defer rows.Close()
	result := make([]Competitor, 0)
	for rows.Next() {
		item, err := scanCompetitor(rows)
		if err != nil {
			return nil, err
		}
		result = append(result, item)
	}
	return result, rows.Err()
}

func (s *Store) validateWorkSource(ctx context.Context, platform, sourceType, sourceID string) error {
	var query string
	switch sourceType {
	case SourceOwned:
		query = `SELECT 1 FROM social_account WHERE account_id=$1 AND platform=$2`
	case SourceCompetitor:
		query = `SELECT 1 FROM creator_competitor WHERE competitor_id=$1 AND platform=$2`
	default:
		return ErrInvalid
	}
	var exists int
	if err := s.db.QueryRowContext(ctx, query, sourceID, platform).Scan(&exists); err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return ErrInvalid
		}
		return databaseError(err)
	}
	return nil
}

func (s *Store) UpsertWork(ctx context.Context, input WorkInput, now time.Time) (Work, bool, error) {
	input.Platform = strings.TrimSpace(input.Platform)
	input.WorkKey = strings.TrimSpace(input.WorkKey)
	input.SourceType = strings.TrimSpace(input.SourceType)
	input.SourceID = strings.TrimSpace(input.SourceID)
	input.AuthorName = strings.TrimSpace(input.AuthorName)
	input.Title = strings.TrimSpace(input.Title)
	input.OriginalURL = strings.TrimSpace(input.OriginalURL)
	input.CoverURL = strings.TrimSpace(input.CoverURL)
	if !ValidatePlatform(input.Platform) || input.WorkKey == "" || input.SourceID == "" ||
		(input.SourceType != SourceOwned && input.SourceType != SourceCompetitor) ||
		utf8.RuneCountInString(input.WorkKey) > 255 || utf8.RuneCountInString(input.Title) > 1000 ||
		utf8.RuneCountInString(input.Body) > 100000 || utf8.RuneCountInString(input.OriginalURL) > 2000 ||
		utf8.RuneCountInString(input.CoverURL) > 2000 || len(input.RawPayload) > maxRawPayloadBytes ||
		input.RawPayload != "" && !json.Valid([]byte(input.RawPayload)) {
		return Work{}, false, ErrInvalid
	}
	if err := s.validateWorkSource(ctx, input.Platform, input.SourceType, input.SourceID); err != nil {
		return Work{}, false, err
	}
	if now.IsZero() {
		now = time.Now().UTC()
	}
	status := input.PublishedAtStatus
	if status == "" {
		status = "verified"
		if input.PublishedAt == nil {
			status = "pending_verification"
		}
	}
	if status != "verified" && status != "pending_verification" && status != "invalid" && status != "future" {
		return Work{}, false, ErrInvalid
	}
	if input.PublishedAt != nil {
		input.PublishedAt = ptrTime(input.PublishedAt.UTC())
		if input.PublishedAt.After(now.UTC()) && status == "verified" {
			status = "future"
		}
	}
	if input.Likes != nil && *input.Likes < 0 || input.CommentsCount != nil && *input.CommentsCount < 0 || input.Shares != nil && *input.Shares < 0 {
		return Work{}, false, ErrInvalid
	}
	if input.CollectCount != nil && *input.CollectCount < 0 || input.PlayCount != nil && *input.PlayCount < 0 {
		return Work{}, false, ErrInvalid
	}

	tx, err := s.db.BeginTx(ctx, nil)
	if err != nil {
		return Work{}, false, fmt.Errorf("begin creator work upsert: %w", err)
	}
	defer tx.Rollback()
	id := newID("work")
	var returnedID string
	var inserted bool
	err = tx.QueryRowContext(ctx, `
		INSERT INTO creator_work (work_id, platform, work_key, source_type, source_id, author_name, title, body,
			published_at, published_at_status, original_url, cover_url, raw_payload, likes, comments_count, shares, collect_count, play_count)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16, $17, $18)
		ON CONFLICT (platform, work_key) DO UPDATE SET
			author_name = CASE WHEN EXCLUDED.author_name = '' THEN creator_work.author_name ELSE EXCLUDED.author_name END,
			title = CASE WHEN EXCLUDED.title = '' THEN creator_work.title ELSE EXCLUDED.title END,
			body = CASE WHEN EXCLUDED.body = '' THEN creator_work.body ELSE EXCLUDED.body END,
			published_at = COALESCE(EXCLUDED.published_at, creator_work.published_at),
			published_at_status = CASE WHEN EXCLUDED.published_at IS NULL THEN creator_work.published_at_status ELSE EXCLUDED.published_at_status END,
			original_url = CASE WHEN EXCLUDED.original_url = '' THEN creator_work.original_url ELSE EXCLUDED.original_url END,
			cover_url = CASE WHEN EXCLUDED.cover_url = '' THEN creator_work.cover_url ELSE EXCLUDED.cover_url END,
			raw_payload = COALESCE(EXCLUDED.raw_payload, creator_work.raw_payload),
			likes = COALESCE(EXCLUDED.likes, creator_work.likes),
			comments_count = COALESCE(EXCLUDED.comments_count, creator_work.comments_count),
			shares = COALESCE(EXCLUDED.shares, creator_work.shares),
			collect_count = COALESCE(EXCLUDED.collect_count, creator_work.collect_count),
			play_count = COALESCE(EXCLUDED.play_count, creator_work.play_count),
			updated_at = now()
		RETURNING work_id, (xmax = 0)`, id, input.Platform, input.WorkKey, input.SourceType, input.SourceID,
		input.AuthorName, input.Title, input.Body, input.PublishedAt, status, input.OriginalURL, input.CoverURL,
		nullableRawPayload(input.RawPayload), input.Likes, input.CommentsCount, input.Shares, input.CollectCount, input.PlayCount).Scan(&returnedID, &inserted)
	if err != nil {
		return Work{}, false, databaseError(err)
	}
	result, err := scanWork(tx.QueryRowContext(ctx, workSelect+` WHERE work_id = $1`, returnedID))
	if err != nil {
		return Work{}, false, rowError(err)
	}
	if err := tx.Commit(); err != nil {
		return Work{}, false, fmt.Errorf("commit creator work upsert: %w", err)
	}
	loadWorkSources(&result)
	return result, inserted, nil
}

func ptrTime(value time.Time) *time.Time { return &value }

func nullableRawPayload(value string) any {
	if value == "" {
		return nil
	}
	return value
}

func scanWork(scanner interface{ Scan(...any) error }) (Work, error) {
	var result Work
	var publishedAt, latestAt, nextAt sql.NullTime
	var likes, commentsCount, shares, collectCount, playCount sql.NullInt64
	var rawPayload sql.NullString
	if err := scanner.Scan(&result.ID, &result.Platform, &result.WorkKey, &result.SourceType, &result.SourceID,
		&result.AuthorName, &result.Title, &result.Body, &publishedAt, &result.PublishedAtStatus,
		&result.OriginalURL, &result.CoverURL, &rawPayload, &likes, &commentsCount, &shares, &collectCount, &playCount, &latestAt, &nextAt,
		&result.MetricStopReason, &result.CreatedAt, &result.UpdatedAt); err != nil {
		return Work{}, err
	}
	result.PublishedAt = nullableTime(publishedAt)
	if rawPayload.Valid {
		result.RawPayload = rawPayload.String
	}
	result.Likes, result.CommentsCount, result.Shares = nullableInt64(likes), nullableInt64(commentsCount), nullableInt64(shares)
	result.CollectCount, result.PlayCount = nullableInt64(collectCount), nullableInt64(playCount)
	result.LatestMetricsAt, result.NextMetricAt = nullableTime(latestAt), nullableTime(nextAt)
	return result, nil
}

const workSelect = `SELECT work_id, platform, work_key, source_type, source_id, author_name, title, body,
	published_at, published_at_status, original_url, cover_url, raw_payload, likes, comments_count, shares, collect_count, play_count,
	latest_metrics_at, next_metric_at, metric_stop_reason, created_at, updated_at FROM creator_work`

func loadWorkSources(work *Work) {
	work.Sources = []WorkSource{{Platform: work.Platform, SourceType: work.SourceType, SourceID: work.SourceID}}
}

func (s *Store) GetWork(ctx context.Context, id string) (Work, error) {
	result, err := scanWork(s.db.QueryRowContext(ctx, workSelect+` WHERE work_id = $1`, id))
	if err != nil {
		return Work{}, rowError(err)
	}
	loadWorkSources(&result)
	return result, nil
}

func (s *Store) GetWorkByKey(ctx context.Context, platform, workKey string) (Work, error) {
	platform, workKey = strings.TrimSpace(platform), strings.TrimSpace(workKey)
	if !ValidatePlatform(platform) || workKey == "" {
		return Work{}, ErrInvalid
	}
	result, err := scanWork(s.db.QueryRowContext(ctx, workSelect+` WHERE platform = $1 AND work_key = $2`, platform, workKey))
	if err != nil {
		return Work{}, rowError(err)
	}
	loadWorkSources(&result)
	return result, nil
}

func (s *Store) ListWorks(ctx context.Context, filter WorkFilter) ([]Work, error) {
	query, args := workSelect, make([]any, 0, 8)
	where := make([]string, 0, 7)
	add := func(clause string, value any) {
		args = append(args, value)
		where = append(where, fmt.Sprintf(clause, len(args)))
	}
	if filter.Platform != "" {
		if !ValidatePlatform(filter.Platform) {
			return nil, ErrInvalid
		}
		add("platform = $%d", filter.Platform)
	}
	if filter.PublishedAtStatus != "" {
		if filter.PublishedAtStatus != "verified" && filter.PublishedAtStatus != "future" && filter.PublishedAtStatus != "pending_verification" && filter.PublishedAtStatus != "invalid" {
			return nil, ErrInvalid
		}
		add("published_at_status = $%d", filter.PublishedAtStatus)
	}
	if filter.SourceType != "" {
		if filter.SourceType != SourceOwned && filter.SourceType != SourceCompetitor {
			return nil, ErrInvalid
		}
		args = append(args, filter.SourceType)
		where = append(where, fmt.Sprintf(`creator_work.source_type = $%d`, len(args)))
	}
	if filter.SourceID != "" {
		args = append(args, filter.SourceID)
		where = append(where, fmt.Sprintf(`creator_work.source_id = $%d`, len(args)))
	}
	if filter.PublishedAfter != nil {
		add("published_at >= $%d", filter.PublishedAfter.UTC())
	}
	if filter.PublishedBefore != nil {
		add("published_at <= $%d", filter.PublishedBefore.UTC())
	}
	if filter.MinLikes != nil {
		if *filter.MinLikes < 0 {
			return nil, ErrInvalid
		}
		where = append(where, fmt.Sprintf("likes IS NOT NULL AND likes >= $%d", len(args)+1))
		args = append(args, *filter.MinLikes)
	}
	if filter.MinComments != nil {
		if *filter.MinComments < 0 {
			return nil, ErrInvalid
		}
		where = append(where, fmt.Sprintf("comments_count IS NOT NULL AND comments_count >= $%d", len(args)+1))
		args = append(args, *filter.MinComments)
	}
	if filter.MinShares != nil {
		if *filter.MinShares < 0 {
			return nil, ErrInvalid
		}
		where = append(where, fmt.Sprintf("shares IS NOT NULL AND shares >= $%d", len(args)+1))
		args = append(args, *filter.MinShares)
	}
	if len(where) > 0 {
		query += ` WHERE ` + strings.Join(where, ` AND `)
	}
	query += ` ORDER BY published_at DESC NULLS LAST, id`
	rows, err := s.db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, databaseError(err)
	}
	result := make([]Work, 0)
	for rows.Next() {
		item, err := scanWork(rows)
		if err != nil {
			_ = rows.Close()
			return nil, err
		}
		result = append(result, item)
	}
	if err := rows.Err(); err != nil {
		_ = rows.Close()
		return nil, err
	}
	if err := rows.Close(); err != nil {
		return nil, err
	}
	for index := range result {
		loadWorkSources(&result[index])
	}
	return result, nil
}

// ListWorksMissingCover 返回已采集到远程封面但本地尚无缓存的作品（用于封面回填）。
// 单次返回上限 40 条，超出部分由后续同步继续回填。
func (s *Store) ListWorksMissingCover(ctx context.Context, sourceID string) ([]Work, error) {
	if sourceID == "" {
		return nil, ErrInvalid
	}
	rows, err := s.db.QueryContext(ctx, workSelect+` WHERE source_type = $1 AND source_id = $2 AND cover_url <> ''
		AND NOT EXISTS (SELECT 1 FROM creator_work_cover c WHERE c.work_id = creator_work.id AND c.variant = 'cover')
		ORDER BY created_at DESC LIMIT 40`, SourceCompetitor, sourceID)
	if err != nil {
		return nil, databaseError(err)
	}
	defer rows.Close()
	result := make([]Work, 0)
	for rows.Next() {
		item, err := scanWork(rows)
		if err != nil {
			return nil, err
		}
		result = append(result, item)
	}
	return result, rows.Err()
}

func (s *Store) RecordMetric(ctx context.Context, input MetricInput, settings Settings, now time.Time) (MetricPoint, error) {
	if input.WorkID == "" || input.CollectedAt.IsZero() || input.Likes != nil && *input.Likes < 0 || input.CommentsCount != nil && *input.CommentsCount < 0 || input.Shares != nil && *input.Shares < 0 || input.CollectCount != nil && *input.CollectCount < 0 || input.PlayCount != nil && *input.PlayCount < 0 {
		return MetricPoint{}, ErrInvalid
	}
	if err := ValidateSettings(SettingsUpdate{LookbackDays: settings.LookbackDays, NewWorkIntervalSeconds: settings.NewWorkIntervalSeconds, MetricInitialIntervalSeconds: settings.MetricInitialIntervalSeconds, MetricMultiplier: settings.MetricMultiplier, MetricMaxIntervalSeconds: settings.MetricMaxIntervalSeconds, MetricAgeSeconds: settings.MetricAgeSeconds}); err != nil {
		return MetricPoint{}, err
	}
	if now.IsZero() {
		now = time.Now().UTC()
	}
	return s.recordMetricWithPlan(ctx, input, settings, now)
}

func nullableArg(value time.Time) any {
	if value.IsZero() {
		return nil
	}
	return value.UTC()
}

// RecordAccountMetric 落库账号画像快照。同一 (account_id, collected_at) 重复采集覆盖更新。
func (s *Store) RecordAccountMetric(ctx context.Context, input AccountMetricInput) error {
	if input.AccountID == "" || input.CollectedAt.IsZero() || input.FollowerCount != nil && *input.FollowerCount < 0 ||
		input.FollowingCount != nil && *input.FollowingCount < 0 || input.TotalFavorited != nil && *input.TotalFavorited < 0 ||
		input.AwemeCount != nil && *input.AwemeCount < 0 || input.FriendCount != nil && *input.FriendCount < 0 {
		return ErrInvalid
	}
	result, err := s.db.ExecContext(ctx, `
		INSERT INTO creator_account_metric (account_id, collected_at, follower_count, following_count, total_favorited, aweme_count, friend_count)
		SELECT account.id, $2, $3, $4, $5, $6, $7 FROM social_account account WHERE account.account_id = $1
		ON CONFLICT (account_id, collected_at) DO UPDATE SET
			follower_count = EXCLUDED.follower_count, following_count = EXCLUDED.following_count,
			total_favorited = EXCLUDED.total_favorited, aweme_count = EXCLUDED.aweme_count,
			friend_count = EXCLUDED.friend_count`,
		input.AccountID, input.CollectedAt.UTC(), input.FollowerCount, input.FollowingCount, input.TotalFavorited, input.AwemeCount, input.FriendCount)
	if err != nil {
		return databaseError(err)
	}
	if affected, err := result.RowsAffected(); err != nil {
		return databaseError(err)
	} else if affected == 0 {
		return ErrNotFound
	}
	return nil
}

// ListAccountMetrics 返回账号画像时序（时间升序），用于粉丝/获赞趋势曲线。
func (s *Store) ListAccountMetrics(ctx context.Context, accountID string) ([]AccountMetricPoint, error) {
	accountID = strings.TrimSpace(accountID)
	if accountID == "" {
		return nil, ErrInvalid
	}
	rows, err := s.db.QueryContext(ctx, `
		SELECT collected_at, follower_count, following_count, total_favorited, aweme_count, friend_count
		FROM creator_account_metric metric JOIN social_account account ON account.id = metric.account_id WHERE account.account_id = $1 ORDER BY metric.collected_at`, accountID)
	if err != nil {
		return nil, databaseError(err)
	}
	defer rows.Close()
	result := make([]AccountMetricPoint, 0)
	for rows.Next() {
		var point AccountMetricPoint
		var follower, following, favorited, aweme, friend sql.NullInt64
		if err := rows.Scan(&point.CollectedAt, &follower, &following, &favorited, &aweme, &friend); err != nil {
			return nil, err
		}
		point.CollectedAt = point.CollectedAt.UTC()
		point.FollowerCount, point.FollowingCount = nullableInt64(follower), nullableInt64(following)
		point.TotalFavorited, point.AwemeCount = nullableInt64(favorited), nullableInt64(aweme)
		point.FriendCount = nullableInt64(friend)
		result = append(result, point)
	}
	return result, rows.Err()
}

func (s *Store) ListMetrics(ctx context.Context, workID string) ([]MetricPoint, error) {
	rows, err := s.db.QueryContext(ctx, `SELECT metric.collected_at, metric.likes, metric.comments_count, metric.shares, metric.collect_count, metric.play_count FROM creator_work_metric metric JOIN creator_work w ON w.id = metric.work_id WHERE w.work_id = $1 ORDER BY metric.collected_at`, workID)
	if err != nil {
		return nil, databaseError(err)
	}
	defer rows.Close()
	result := make([]MetricPoint, 0)
	for rows.Next() {
		var point MetricPoint
		var likes, commentsCount, shares, collectCount, playCount sql.NullInt64
		if err := rows.Scan(&point.CollectedAt, &likes, &commentsCount, &shares, &collectCount, &playCount); err != nil {
			return nil, err
		}
		point.CollectedAt = point.CollectedAt.UTC()
		point.Likes, point.CommentsCount, point.Shares = nullableInt64(likes), nullableInt64(commentsCount), nullableInt64(shares)
		point.CollectCount, point.PlayCount = nullableInt64(collectCount), nullableInt64(playCount)
		result = append(result, point)
	}
	return result, rows.Err()
}

func (s *Store) SaveComment(ctx context.Context, input CommentInput) (Comment, bool, error) {
	input.Platform, input.CommentKey, input.WorkID, input.AuthorUID, input.AuthorName, input.CommentType = strings.TrimSpace(input.Platform), strings.TrimSpace(input.CommentKey), strings.TrimSpace(input.WorkID), strings.TrimSpace(input.AuthorUID), strings.TrimSpace(input.AuthorName), strings.TrimSpace(input.CommentType)
	if !ValidatePlatform(input.Platform) || input.CommentKey == "" || input.WorkID == "" || strings.TrimSpace(input.Content) == "" || (input.CommentType != "top_level" && input.CommentType != "unknown") || utf8.RuneCountInString(input.Content) > 10000 || len(input.RawPayload) > maxRawPayloadBytes || input.RawPayload != "" && !json.Valid([]byte(input.RawPayload)) {
		return Comment{}, false, ErrInvalid
	}
	work, err := s.GetWork(ctx, input.WorkID)
	if err != nil {
		return Comment{}, false, err
	}
	if work.Platform != input.Platform {
		return Comment{}, false, ErrInvalid
	}
	id := newID("comment")
	var returnedID string
	var inserted bool
	err = s.db.QueryRowContext(ctx, `INSERT INTO creator_comment (comment_id, platform, comment_key, work_id, author_uid, author_name, content, raw_payload, published_at, comment_type) VALUES ($1,$2,$3,(SELECT w.id FROM creator_work w WHERE w.work_id = $4),$5,$6,$7,$8,$9,$10) ON CONFLICT (platform, comment_key) DO UPDATE SET work_id = EXCLUDED.work_id, author_uid = EXCLUDED.author_uid, author_name = EXCLUDED.author_name, content = EXCLUDED.content, raw_payload = COALESCE(EXCLUDED.raw_payload, creator_comment.raw_payload), published_at = EXCLUDED.published_at, comment_type = EXCLUDED.comment_type RETURNING comment_id, (xmax = 0)`, id, input.Platform, input.CommentKey, input.WorkID, input.AuthorUID, input.AuthorName, input.Content, nullableRawPayload(input.RawPayload), input.PublishedAt, input.CommentType).Scan(&returnedID, &inserted)
	if err != nil {
		return Comment{}, false, databaseError(err)
	}
	result, err := s.GetComment(ctx, returnedID)
	return result, inserted, err
}

func scanComment(scanner interface{ Scan(...any) error }) (Comment, error) {
	var result Comment
	var publishedAt sql.NullTime
	var rawPayload sql.NullString
	if err := scanner.Scan(&result.ID, &result.Platform, &result.CommentKey, &result.WorkID, &result.AuthorUID, &result.AuthorName, &result.Content, &rawPayload, &publishedAt, &result.CollectedAt, &result.CommentType); err != nil {
		return Comment{}, err
	}
	result.PublishedAt = nullableTime(publishedAt)
	if rawPayload.Valid {
		result.RawPayload = rawPayload.String
	}
	result.CollectedAt = result.CollectedAt.UTC()
	return result, nil
}

const commentSelect = `SELECT creator_comment.comment_id, creator_comment.platform, creator_comment.comment_key, work.work_id, creator_comment.author_uid, creator_comment.author_name, creator_comment.content, creator_comment.raw_payload, creator_comment.published_at, creator_comment.collected_at, creator_comment.comment_type
	FROM creator_comment
	JOIN creator_work work ON work.id = creator_comment.work_id`

func (s *Store) GetComment(ctx context.Context, id string) (Comment, error) {
	result, err := scanComment(s.db.QueryRowContext(ctx, commentSelect+` WHERE creator_comment.comment_id = $1`, id))
	return result, rowError(err)
}

func (s *Store) GetCommentByKey(ctx context.Context, platform, commentKey string) (Comment, error) {
	platform, commentKey = strings.TrimSpace(platform), strings.TrimSpace(commentKey)
	if !ValidatePlatform(platform) || commentKey == "" {
		return Comment{}, ErrInvalid
	}
	result, err := scanComment(s.db.QueryRowContext(ctx, commentSelect+` WHERE creator_comment.platform = $1 AND creator_comment.comment_key = $2`, platform, commentKey))
	return result, rowError(err)
}

// SaveWorkCover 缓存作品封面图（带签名的 douyinpic URL 会过期，存字节后经本地接口展示）。
func (s *Store) SaveWorkCover(ctx context.Context, workID, variant, contentType string, data []byte) error {
	if workID == "" || variant == "" || contentType == "" || len(data) == 0 || len(data) > maxWorkCoverBytes {
		return ErrInvalid
	}
	_, err := s.db.ExecContext(ctx, `
		INSERT INTO creator_work_cover (work_id, variant, content_type, data, fetched_at)
		SELECT w.id, $2, $3, $4, now() FROM creator_work w WHERE w.work_id = $1
		ON CONFLICT (work_id, variant) DO UPDATE SET content_type = EXCLUDED.content_type, data = EXCLUDED.data, fetched_at = now()`,
		workID, variant, contentType, data)
	if err != nil {
		return databaseError(err)
	}
	return nil
}

func (s *Store) GetWorkCover(ctx context.Context, workID, variant string) (contentType string, data []byte, err error) {
	if workID == "" || variant == "" {
		return "", nil, ErrInvalid
	}
	err = s.db.QueryRowContext(ctx, `SELECT cover.content_type, cover.data FROM creator_work_cover cover JOIN creator_work w ON w.id = cover.work_id WHERE w.work_id = $1 AND cover.variant = $2`, workID, variant).Scan(&contentType, &data)
	if errors.Is(err, sql.ErrNoRows) {
		return "", nil, ErrNotFound
	}
	if err != nil {
		return "", nil, databaseError(err)
	}
	return contentType, data, nil
}

const maxWorkCoverBytes = 4 << 20

func pageBounds(page, pageSize int) (int, int, error) {
	if page < 1 || pageSize < 1 || pageSize > 100 {
		return 0, 0, ErrInvalid
	}
	if page > int(maxDurationSeconds) || pageSize > int(maxDurationSeconds)/page {
		return 0, 0, ErrInvalid
	}
	return (page - 1) * pageSize, pageSize, nil
}

func slicePage[T any](items []T, page, pageSize int) (Page[T], error) {
	offset, limit, err := pageBounds(page, pageSize)
	if err != nil {
		return Page[T]{}, err
	}
	if offset > len(items) {
		offset = len(items)
	}
	end := offset + limit
	if end > len(items) {
		end = len(items)
	}
	data := append([]T{}, items[offset:end]...)
	return Page[T]{Data: data, Page: page, PageSize: pageSize, Total: len(items), HasNext: end < len(items)}, nil
}

func (s *Store) ListWorksPage(ctx context.Context, filter WorkFilter, page, pageSize int) (Page[Work], error) {
	items, err := s.ListWorks(ctx, filter)
	if err != nil {
		return Page[Work]{}, err
	}
	if filter.Growth.Hours != 0 || filter.Growth.MinLikes != nil {
		ids := make([]string, 0, len(items))
		for _, item := range items {
			ids = append(ids, item.ID)
		}
		growth, growthErr := s.LoadWorksGrowth(ctx, ids, filter.Growth)
		if growthErr != nil {
			return Page[Work]{}, growthErr
		}
		items, err = ApplyWorkGrowthFilter(items, growth, filter.Growth)
		if err != nil {
			return Page[Work]{}, err
		}
	}
	return slicePage(items, page, pageSize)
}

func (s *Store) ListCommentsPage(ctx context.Context, platform, workID string, page, pageSize int) (Page[Comment], error) {
	items, err := s.ListComments(ctx, platform, workID)
	if err != nil {
		return Page[Comment]{}, err
	}
	return slicePage(items, page, pageSize)
}

func (s *Store) ListComments(ctx context.Context, platform, workID string) ([]Comment, error) {
	query, args := commentSelect, []any{}
	where := []string{}
	if platform != "" {
		if !ValidatePlatform(platform) {
			return nil, ErrInvalid
		}
		args = append(args, platform)
		where = append(where, fmt.Sprintf("creator_comment.platform = $%d", len(args)))
	}
	if workID != "" {
		args = append(args, workID)
		where = append(where, fmt.Sprintf("work.work_id = $%d", len(args)))
	}
	if len(where) > 0 {
		query += ` WHERE ` + strings.Join(where, ` AND `)
	}
	query += ` ORDER BY creator_comment.published_at DESC NULLS LAST, creator_comment.collected_at DESC, creator_comment.comment_id`
	rows, err := s.db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, databaseError(err)
	}
	defer rows.Close()
	result := make([]Comment, 0)
	for rows.Next() {
		item, err := scanComment(rows)
		if err != nil {
			return nil, err
		}
		result = append(result, item)
	}
	return result, rows.Err()
}