package main

import (
	"context"
	"fmt"
	"strings"

	"github.com/descrybe/descrybe-v2/apps/api/internal/auth"
	"github.com/descrybe/descrybe-v2/apps/api/internal/billing"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
)

const defaultMigratorDemoCompany = "Platform Demo"

// ensureDemoUser upserts a local demo account (no Clerk), makes them platform admin,
// and binds them only to a standalone Platform Demo company (never A1 / every tenant).
func ensureDemoUser(
	ctx context.Context,
	pg *pgxpool.Pool,
	email, password, displayName, localDemoName string,
	dryRun bool,
	report map[string]int,
) (*DemoReport, error) {
	emailNorm := strings.ToLower(strings.TrimSpace(email))
	if emailNorm == "" || password == "" {
		return nil, fmt.Errorf("demo email and password required")
	}
	if localDemoName == "" {
		localDemoName = defaultMigratorDemoCompany
	}
	if displayName == "" {
		displayName = "Demo User"
	}
	out := &DemoReport{
		Email:         emailNorm,
		PasswordSet:   true,
		PlatformAdmin: true,
		Note:          "Password documented in docs/portable-mysql-pg-migration.md (not written to report JSON).",
	}
	if dryRun {
		report["demo_user"] = 1
		out.Note = "dry-run: demo user not written"
		out.PasswordSet = false
		return out, nil
	}

	hash, err := auth.HashPassword(password)
	if err != nil {
		return nil, err
	}

	tx, err := pg.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)

	var userID uuid.UUID
	err = tx.QueryRow(ctx, `
		INSERT INTO users (
			email, name, password_hash, must_set_password,
			is_platform_admin, is_active, updated_at
		) VALUES ($1, $2, $3, false, true, true, now())
		ON CONFLICT (email) DO UPDATE SET
			name = EXCLUDED.name,
			password_hash = EXCLUDED.password_hash,
			must_set_password = false,
			is_platform_admin = true,
			is_active = true,
			updated_at = now()
		RETURNING id`, emailNorm, displayName, hash).Scan(&userID)
	if err != nil {
		return nil, fmt.Errorf("upsert demo user: %w", err)
	}
	out.UserID = userID.String()

	demoCompanyID, demoName, err := ensureMigratorDemoCompany(ctx, tx, localDemoName)
	if err != nil {
		return nil, err
	}
	out.PrimaryCompany = demoCompanyID.String()
	out.PrimaryName = demoName

	ct, err := tx.Exec(ctx, `
		INSERT INTO memberships (company_id, user_id, role, status)
		VALUES ($1, $2, 'admin', 'active')
		ON CONFLICT (company_id, user_id) DO UPDATE
		SET role = 'admin', status = 'active', updated_at = now()`, demoCompanyID, userID)
	if err != nil {
		return nil, fmt.Errorf("demo membership: %w", err)
	}
	if _, err := tx.Exec(ctx, `
		DELETE FROM memberships
		WHERE user_id = $1 AND company_id <> $2`, userID, demoCompanyID); err != nil {
		return nil, fmt.Errorf("remove non-demo memberships: %w", err)
	}
	out.Memberships = ct.RowsAffected()

	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}
	report["demo_user"] = 1
	report["demo_memberships"] = int(out.Memberships)
	return out, nil
}

func ensureMigratorDemoCompany(ctx context.Context, tx pgx.Tx, name string) (uuid.UUID, string, error) {
	name = strings.TrimSpace(name)
	if name == "" {
		name = defaultMigratorDemoCompany
	}
	if strings.EqualFold(name, "A1 Slovenija") || strings.EqualFold(name, "A1") || strings.EqualFold(name, "Local Demo Co") {
		return uuid.Nil, "", fmt.Errorf("demo company name %q collides with A1 tenant — use %q", name, defaultMigratorDemoCompany)
	}

	var id uuid.UUID
	err := tx.QueryRow(ctx, `
		SELECT c.id
		FROM companies c
		WHERE c.name = $1
		  AND COALESCE(c.legacy_company_id, '') <> $2
		ORDER BY c.created_at ASC
		LIMIT 1`, name, billing.A1LegacyCompanyID).Scan(&id)
	if err == nil {
		if _, err := tx.Exec(ctx, `INSERT INTO company_settings (company_id) VALUES ($1) ON CONFLICT DO NOTHING`, id); err != nil {
			return uuid.Nil, "", err
		}
		if _, err := tx.Exec(ctx, `INSERT INTO credit_balances (company_id) VALUES ($1) ON CONFLICT DO NOTHING`, id); err != nil {
			return uuid.Nil, "", err
		}
		return id, name, nil
	}
	if err != pgx.ErrNoRows {
		return uuid.Nil, "", err
	}

	err = tx.QueryRow(ctx, `INSERT INTO companies (name) VALUES ($1) RETURNING id`, name).Scan(&id)
	if err != nil {
		return uuid.Nil, "", err
	}
	if _, err := tx.Exec(ctx, `INSERT INTO company_settings (company_id) VALUES ($1) ON CONFLICT DO NOTHING`, id); err != nil {
		return uuid.Nil, "", err
	}
	if _, err := tx.Exec(ctx, `INSERT INTO credit_balances (company_id) VALUES ($1) ON CONFLICT DO NOTHING`, id); err != nil {
		return uuid.Nil, "", err
	}
	return id, name, nil
}