package db

import (
	"github.com/go-gormigrate/gormigrate/v2"
	"gorm.io/gorm"
)

type Migrator struct {
	Schema     string
	TenantId   uint
	DB         *gorm.DB
	Migrations []*gormigrate.Migration
	Log        func(string, ...any)
}

func (m *Migrator) Migrate() error {
	return m.migrate(func(migrator *gormigrate.Gormigrate) error {
		return migrator.Migrate()
	})
}

func (m *Migrator) MigrateTo(migrationID string) error {
	return m.migrate(func(migrator *gormigrate.Gormigrate) error {
		return migrator.MigrateTo(migrationID)
	})
}

func (m *Migrator) migrate(fn func(migrator *gormigrate.Gormigrate) error) error {
	if m.TenantId > 0 {
		m.Log("⏳ migrating tables for tenant %d", m.TenantId)
	} else {
		m.Log("⏳ migrating public tables")
	}

	if err := CreateSchema(m.DB, m.Schema); err != nil {
		if m.TenantId > 0 {
			m.Log("❌ failed to create schema for tenant %d: %s", m.TenantId, err)
		} else {
			m.Log("❌ failed to create public schema: %s", err)
		}
		return err
	}

	tx := m.DB.Begin()
	defer func() {
		if tx.Error == nil {
			tx.Commit()
			if m.TenantId > 0 {
				m.Log("✅ private tables migrated for tenant %d", m.TenantId)
			} else {
				m.Log("✅ public tables migrated for all tenants")
			}
		} else {
			tx.Rollback()
		}
	}()

	unlock, err := LockSchema(tx, m.Schema)
	if err != nil {
		m.Log("❌ failed to acquire advisory lock: %w", err)
		return err
	}
	defer unlock()

	reset := func() error { return nil }
	if m.TenantId > 0 {
		reset, err = UseTenant(tx, m.TenantId)
		if err != nil {
			m.Log("❌ failed to switch schema for tenant %d: %w", m.TenantId, err)
			return err
		}
	}
	defer reset()

	err = fn(gormigrate.New(tx, &gormigrate.Options{
		TableName: tx.NamingStrategy.TableName("migrations"),
	}, m.Migrations))
	if err != nil {
		if m.TenantId > 0 {
			m.Log("❌ failed to call migrate for tenant %d: %w", m.TenantId, err)
		} else {
			m.Log("❌ failed to migrate public tables: %w", err)
		}
		return err
	}

	return nil
}

func (m *Migrator) RollbackLast() error {
	return m.rollback(func(migrator *gormigrate.Gormigrate) error {
		return migrator.RollbackLast()
	})
}

func (m *Migrator) RollbackTo(migrationID string) error {
	return m.rollback(func(migrator *gormigrate.Gormigrate) error {
		return migrator.MigrateTo(migrationID)
	})
}

func (m *Migrator) rollback(fn func(migrator *gormigrate.Gormigrate) error) error {
	if m.TenantId > 0 {
		m.Log("⏳ rollbacking tables for tenant %d", m.TenantId)
	} else {
		m.Log("⏳ rollbacking public tables")
	}

	if err := CreateSchema(m.DB, m.Schema); err != nil {
		if m.TenantId > 0 {
			m.Log("❌ failed to create schema for tenant %d: %s", m.TenantId, err)
		} else {
			m.Log("❌ failed to create public schema: %s", err)
		}
		return err
	}

	tx := m.DB.Begin()
	defer func() {
		if tx.Error == nil {
			tx.Commit()
			if m.TenantId > 0 {
				m.Log("✅ private tables rollbacked for tenant %d", m.TenantId)
			} else {
				m.Log("✅ public tables rollbacked for all tenants")
			}
		} else {
			tx.Rollback()
		}
	}()

	unlock, err := LockSchema(tx, m.Schema)
	if err != nil {
		m.Log("❌ failed to acquire advisory lock: %w", err)
		return err
	}
	defer unlock()

	reset := func() error { return nil }
	if m.TenantId > 0 {
		reset, err = UseTenant(tx, m.TenantId)
		if err != nil {
			m.Log("❌ failed to switch schema for tenant %d: %w", m.TenantId, err)
			return err
		}
	}
	defer reset()

	err = fn(gormigrate.New(tx, &gormigrate.Options{
		TableName: tx.NamingStrategy.TableName("migrations"),
	}, m.Migrations))
	if err != nil {
		if m.TenantId > 0 {
			m.Log("❌ failed to call rollback for tenant %d: %w", m.TenantId, err)
		} else {
			m.Log("❌ failed to rollback public tables: %w", err)
		}
		return err
	}

	return nil
}