package db

import (
	"context"
	"database/sql"
	"fmt"
	"time"

	_ "github.com/lib/pq"
)

type PostgresDB struct {
	db *sql.DB
}

func NewPostgresDB(databaseURL string) (*PostgresDB, error) {
	db, err := sql.Open("postgres", databaseURL)
	if err != nil {
		return nil, fmt.Errorf("failed to open database: %w", err)
	}

	db.SetMaxOpenConns(25)
	db.SetMaxIdleConns(5)
	db.SetConnMaxLifetime(5 * time.Minute)

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	if err := db.PingContext(ctx); err != nil {
		return nil, fmt.Errorf("failed to ping database: %w", err)
	}

	return &PostgresDB{db: db}, nil
}

func (p *PostgresDB) Close() error {
	return p.db.Close()
}

func (p *PostgresDB) DB() *sql.DB {
	return p.db
}

func (p *PostgresDB) RunMigrations(ctx context.Context) error {
	migrations := []string{
		`CREATE TABLE IF NOT EXISTS digests (
			id SERIAL PRIMARY KEY,
			topic VARCHAR(100) NOT NULL,
			region VARCHAR(50) NOT NULL,
			cluster_title VARCHAR(500) NOT NULL,
			summary_ru TEXT NOT NULL,
			citations JSONB DEFAULT '[]',
			sources_count INT DEFAULT 0,
			follow_up JSONB DEFAULT '[]',
			thumbnail TEXT,
			short_description TEXT,
			main_url TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			updated_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(topic, region, cluster_title)
		)`,
		`CREATE INDEX IF NOT EXISTS idx_digests_topic_region ON digests(topic, region)`,
		`CREATE INDEX IF NOT EXISTS idx_digests_main_url ON digests(main_url)`,
		`CREATE TABLE IF NOT EXISTS article_summaries (
			id SERIAL PRIMARY KEY,
			url_hash VARCHAR(64) NOT NULL UNIQUE,
			url TEXT NOT NULL,
			events JSONB NOT NULL DEFAULT '[]',
			created_at TIMESTAMPTZ DEFAULT NOW(),
			expires_at TIMESTAMPTZ DEFAULT NOW() + INTERVAL '7 days'
		)`,
		`CREATE INDEX IF NOT EXISTS idx_article_summaries_url_hash ON article_summaries(url_hash)`,
		`CREATE INDEX IF NOT EXISTS idx_article_summaries_expires ON article_summaries(expires_at)`,
		`CREATE TABLE IF NOT EXISTS collections (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			user_id UUID NOT NULL,
			name VARCHAR(255) NOT NULL,
			description TEXT,
			is_public BOOLEAN DEFAULT FALSE,
			context_enabled BOOLEAN DEFAULT TRUE,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			updated_at TIMESTAMPTZ DEFAULT NOW()
		)`,
		`CREATE INDEX IF NOT EXISTS idx_collections_user ON collections(user_id)`,
		`CREATE TABLE IF NOT EXISTS collection_items (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			collection_id UUID NOT NULL REFERENCES collections(id) ON DELETE CASCADE,
			item_type VARCHAR(50) NOT NULL,
			title VARCHAR(500),
			content TEXT,
			url TEXT,
			metadata JSONB DEFAULT '{}',
			created_at TIMESTAMPTZ DEFAULT NOW(),
			sort_order INT DEFAULT 0
		)`,
		`CREATE INDEX IF NOT EXISTS idx_collection_items_collection ON collection_items(collection_id)`,
		`CREATE TABLE IF NOT EXISTS uploaded_files (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			user_id UUID NOT NULL,
			filename VARCHAR(500) NOT NULL,
			file_type VARCHAR(100) NOT NULL,
			file_size BIGINT NOT NULL,
			storage_path TEXT NOT NULL,
			extracted_text TEXT,
			metadata JSONB DEFAULT '{}',
			created_at TIMESTAMPTZ DEFAULT NOW()
		)`,
		`CREATE INDEX IF NOT EXISTS idx_uploaded_files_user ON uploaded_files(user_id)`,
		`CREATE TABLE IF NOT EXISTS research_sessions (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			user_id UUID,
			collection_id UUID REFERENCES collections(id) ON DELETE SET NULL,
			query TEXT NOT NULL,
			focus_mode VARCHAR(50) DEFAULT 'all',
			optimization_mode VARCHAR(50) DEFAULT 'balanced',
			sources JSONB DEFAULT '[]',
			response_blocks JSONB DEFAULT '[]',
			final_answer TEXT,
			citations JSONB DEFAULT '[]',
			created_at TIMESTAMPTZ DEFAULT NOW(),
			completed_at TIMESTAMPTZ
		)`,
		`CREATE INDEX IF NOT EXISTS idx_research_sessions_user ON research_sessions(user_id)`,
		`CREATE INDEX IF NOT EXISTS idx_research_sessions_collection ON research_sessions(collection_id)`,
	}

	for _, migration := range migrations {
		if _, err := p.db.ExecContext(ctx, migration); err != nil {
			return fmt.Errorf("migration failed: %w", err)
		}
	}

	return nil
}