package store

import (
	"context"
	"fmt"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgconn"
	"github.com/jackc/pgx/v5/pgxpool"
)

// DBTX is the interface for database query operations.
// Satisfied by *pgxpool.Pool, *pgx.Conn, and pgx.Tx.
type DBTX interface {
	Exec(ctx context.Context, sql string, arguments ...any) (pgconn.CommandTag, error)
	Query(ctx context.Context, sql string, args ...any) (pgx.Rows, error)
	QueryRow(ctx context.Context, sql string, args ...any) pgx.Row
}

// Store provides database operations for the dev-pod API.
type Store struct {
	db DBTX
}

// New creates a Store with the given database connection.
func New(db DBTX) *Store {
	return &Store{db: db}
}

// NewPool creates a new pgx connection pool.
func NewPool(ctx context.Context, databaseURL string) (*pgxpool.Pool, error) {
	pool, err := pgxpool.New(ctx, databaseURL)
	if err != nil {
		return nil, fmt.Errorf("connect to database: %w", err)
	}
	if err := pool.Ping(ctx); err != nil {
		pool.Close()
		return nil, fmt.Errorf("ping database: %w", err)
	}
	return pool, nil
}

// Migrate runs database migrations to create required tables.
func (s *Store) Migrate(ctx context.Context) error {
	migrations := []string{
		`CREATE TABLE IF NOT EXISTS users (
			id TEXT PRIMARY KEY,
			created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
			max_concurrent_pods INTEGER NOT NULL DEFAULT 3,
			max_cpu_per_pod INTEGER NOT NULL DEFAULT 8,
			max_ram_gb_per_pod INTEGER NOT NULL DEFAULT 16,
			monthly_pod_hours INTEGER NOT NULL DEFAULT 500,
			monthly_ai_requests INTEGER NOT NULL DEFAULT 10000
		)`,
		`CREATE TABLE IF NOT EXISTS api_keys (
			key_hash TEXT PRIMARY KEY,
			user_id TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
			role TEXT NOT NULL DEFAULT 'user',
			created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
			last_used_at TIMESTAMPTZ
		)`,
		`CREATE TABLE IF NOT EXISTS usage_records (
			id BIGSERIAL PRIMARY KEY,
			user_id TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
			pod_name TEXT NOT NULL,
			event_type TEXT NOT NULL,
			value DOUBLE PRECISION,
			recorded_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
		)`,
		`CREATE INDEX IF NOT EXISTS idx_usage_user_month ON usage_records(user_id, recorded_at)`,
		`ALTER TABLE users ADD COLUMN IF NOT EXISTS forgejo_token TEXT NOT NULL DEFAULT ''`,
		`CREATE TABLE IF NOT EXISTS runners (
			id TEXT PRIMARY KEY,
			user_id TEXT NOT NULL REFERENCES users(id),
			repo_url TEXT NOT NULL,
			branch TEXT NOT NULL DEFAULT 'main',
			tools TEXT NOT NULL DEFAULT '',
			task TEXT NOT NULL DEFAULT '',
			status TEXT NOT NULL DEFAULT 'received',
			forgejo_runner_id TEXT NOT NULL DEFAULT '',
			webhook_delivery_id TEXT NOT NULL DEFAULT '',
			pod_name TEXT NOT NULL DEFAULT '',
			cpu_req TEXT NOT NULL DEFAULT '2',
			mem_req TEXT NOT NULL DEFAULT '4Gi',
			created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
			claimed_at TIMESTAMPTZ,
			completed_at TIMESTAMPTZ
		)`,
		`CREATE UNIQUE INDEX IF NOT EXISTS idx_runners_webhook_delivery
			ON runners(webhook_delivery_id) WHERE webhook_delivery_id != ''`,
		`CREATE INDEX IF NOT EXISTS idx_runners_status ON runners(status)`,
		`ALTER TABLE users ADD COLUMN IF NOT EXISTS tailscale_key TEXT NOT NULL DEFAULT ''`,
	}
	for _, m := range migrations {
		if _, err := s.db.Exec(ctx, m); err != nil {
			return fmt.Errorf("run migration: %w", err)
		}
	}
	return nil
}