package db

import (
	"context"
	"database/sql"
	"encoding/json"
	"time"
)

type DigestCitation struct {
	Index  int    `json:"index"`
	URL    string `json:"url"`
	Title  string `json:"title"`
	Domain string `json:"domain"`
}

type Digest struct {
	ID               int64            `json:"id"`
	Topic            string           `json:"topic"`
	Region           string           `json:"region"`
	ClusterTitle     string           `json:"clusterTitle"`
	SummaryRu        string           `json:"summaryRu"`
	Citations        []DigestCitation `json:"citations"`
	SourcesCount     int              `json:"sourcesCount"`
	FollowUp         []string         `json:"followUp"`
	Thumbnail        string           `json:"thumbnail"`
	ShortDescription string           `json:"shortDescription"`
	MainURL          string           `json:"mainUrl"`
	CreatedAt        time.Time        `json:"createdAt"`
	UpdatedAt        time.Time        `json:"updatedAt"`
}

type DigestRepository struct {
	db *PostgresDB
}

func NewDigestRepository(db *PostgresDB) *DigestRepository {
	return &DigestRepository{db: db}
}

func (r *DigestRepository) GetByTopicRegionTitle(ctx context.Context, topic, region, title string) (*Digest, error) {
	query := `
		SELECT id, topic, region, cluster_title, summary_ru, citations, sources_count, 
			   follow_up, thumbnail, short_description, main_url, created_at, updated_at
		FROM digests 
		WHERE topic = $1 AND region = $2 AND cluster_title = $3
	`

	var d Digest
	var citationsJSON, followUpJSON []byte

	err := r.db.db.QueryRowContext(ctx, query, topic, region, title).Scan(
		&d.ID, &d.Topic, &d.Region, &d.ClusterTitle, &d.SummaryRu,
		&citationsJSON, &d.SourcesCount, &followUpJSON,
		&d.Thumbnail, &d.ShortDescription, &d.MainURL,
		&d.CreatedAt, &d.UpdatedAt,
	)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	json.Unmarshal(citationsJSON, &d.Citations)
	json.Unmarshal(followUpJSON, &d.FollowUp)

	return &d, nil
}

func (r *DigestRepository) GetByURL(ctx context.Context, url string) (*Digest, error) {
	query := `
		SELECT id, topic, region, cluster_title, summary_ru, citations, sources_count,
			   follow_up, thumbnail, short_description, main_url, created_at, updated_at
		FROM digests 
		WHERE main_url = $1
		LIMIT 1
	`

	var d Digest
	var citationsJSON, followUpJSON []byte

	err := r.db.db.QueryRowContext(ctx, query, url).Scan(
		&d.ID, &d.Topic, &d.Region, &d.ClusterTitle, &d.SummaryRu,
		&citationsJSON, &d.SourcesCount, &followUpJSON,
		&d.Thumbnail, &d.ShortDescription, &d.MainURL,
		&d.CreatedAt, &d.UpdatedAt,
	)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	json.Unmarshal(citationsJSON, &d.Citations)
	json.Unmarshal(followUpJSON, &d.FollowUp)

	return &d, nil
}

func (r *DigestRepository) GetByTopicRegion(ctx context.Context, topic, region string, limit int) ([]*Digest, error) {
	query := `
		SELECT id, topic, region, cluster_title, summary_ru, citations, sources_count,
			   follow_up, thumbnail, short_description, main_url, created_at, updated_at
		FROM digests 
		WHERE topic = $1 AND region = $2
		ORDER BY created_at DESC
		LIMIT $3
	`

	rows, err := r.db.db.QueryContext(ctx, query, topic, region, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var digests []*Digest
	for rows.Next() {
		var d Digest
		var citationsJSON, followUpJSON []byte

		if err := rows.Scan(
			&d.ID, &d.Topic, &d.Region, &d.ClusterTitle, &d.SummaryRu,
			&citationsJSON, &d.SourcesCount, &followUpJSON,
			&d.Thumbnail, &d.ShortDescription, &d.MainURL,
			&d.CreatedAt, &d.UpdatedAt,
		); err != nil {
			return nil, err
		}

		json.Unmarshal(citationsJSON, &d.Citations)
		json.Unmarshal(followUpJSON, &d.FollowUp)
		digests = append(digests, &d)
	}

	return digests, nil
}

func (r *DigestRepository) Upsert(ctx context.Context, d *Digest) error {
	citationsJSON, _ := json.Marshal(d.Citations)
	followUpJSON, _ := json.Marshal(d.FollowUp)

	query := `
		INSERT INTO digests (topic, region, cluster_title, summary_ru, citations, sources_count,
							 follow_up, thumbnail, short_description, main_url)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
		ON CONFLICT (topic, region, cluster_title) 
		DO UPDATE SET 
			summary_ru = EXCLUDED.summary_ru,
			citations = EXCLUDED.citations,
			sources_count = EXCLUDED.sources_count,
			follow_up = EXCLUDED.follow_up,
			thumbnail = EXCLUDED.thumbnail,
			short_description = EXCLUDED.short_description,
			main_url = EXCLUDED.main_url,
			updated_at = NOW()
	`

	_, err := r.db.db.ExecContext(ctx, query,
		d.Topic, d.Region, d.ClusterTitle, d.SummaryRu,
		citationsJSON, d.SourcesCount, followUpJSON,
		d.Thumbnail, d.ShortDescription, d.MainURL,
	)
	return err
}

func (r *DigestRepository) DeleteByTopicRegion(ctx context.Context, topic, region string) (int64, error) {
	result, err := r.db.db.ExecContext(ctx,
		"DELETE FROM digests WHERE topic = $1 AND region = $2",
		topic, region,
	)
	if err != nil {
		return 0, err
	}
	return result.RowsAffected()
}