package db

import (
	"context"
	"fmt"
	"log"

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

var migrationsTable string = "schema_migrations"

func RunMigrations() {
	log.Print("[tixe/db] Running migrations")

	var ranTimestamp pgtype.Timestamptz
	var schemaVersion int = 0

	schemaVersionQuery := fmt.Sprintf(
		`SELECT ran_timestamp, schema_version
			FROM %s
				ORDER BY schema_version
					DESC LIMIT 1;`,
		migrationsTable)
	err := PgPool.QueryRow(context.Background(), schemaVersionQuery).Scan(&ranTimestamp, &schemaVersion)
	if err != nil {
		log.Print("[tixe/db] No schema version found, running all migrations")
	} else {
		log.Printf("[tixe/db] Last migration ran on %s, with schema version %d", ranTimestamp.Time, schemaVersion)
	}

	migrations := migrations()
	if schemaVersion != len(migrations) {
		for i := 0; i < len(migrations); i++ {
			if i >= schemaVersion {
				log.Printf("[tixe/db] Running migration %d", i + 1) // + 1 is just a visual thing
				_, err := PgPool.Exec(context.Background(), migrations[i])
				if err != nil {
					log.Fatalf("[tixe/db] Migration %d failed to run!", i)
				}
			}
		}

		// We are now up to date
		schemaVersion = len(migrations)
		// Create a new entry in the migrations table
		schemaMigrationInsertQuery := fmt.Sprintf(
			`INSERT INTO %s(ran_timestamp, schema_version) VALUES(CURRENT_TIMESTAMP, %d);`,
			migrationsTable, schemaVersion)
		_, err = PgPool.Exec(context.Background(), schemaMigrationInsertQuery)
		if err != nil {
			log.Fatal("[tixe/db] Migrations ran, but was not able to create migration entry")
		} else {
			log.Print("[tixe/db] Migrations ran successfully")
		}
	} else {
		log.Printf("[tixe/db] Already on schema version %d, no migrations to run", schemaVersion)
	}
}

func migrations() []string {
	return []string{
		fmt.Sprintf(`CREATE TABLE %s (
			ran_timestamp timestamp,
			schema_version integer
		)`, migrationsTable),
		fmt.Sprintf(`CREATE TABLE users (
			id CHAR(26) NOT NULL PRIMARY KEY,
			display_name TEXT NOT NULL,
			oidc_subject TEXT
		)`),
		fmt.Sprintf(`CREATE TABLE tags (
			id CHAR(26) NOT NULL PRIMARY KEY,
			user_id CHAR(26) NOT NULL REFERENCES users(id),
			tag TEXT NOT NULL,
			UNIQUE (user_id, tag)
		)`),
	}
}