// Package migrations contains the reviewed SQL bundled with the application.
// SQL execution and database lifecycle remain in internal/data.
package migrations

import (
	_ "embed"
	"fmt"
	"regexp"
	"strings"
)

//go:embed legacy-framework.sql
var frameworkSQL string

//go:embed cleanup-legacy.sql
var cleanupSQL string

func FrameworkSQL() string { return frameworkSQL }
func CleanupSQL() string   { return cleanupSQL }

// Statements understands the DELIMITER directives in the bundled, trusted
// scripts. It does not split stored-procedure bodies on their semicolons.
func Statements(source string) ([]string, error) {
	delimiter := ";"
	var buffer strings.Builder
	var statements []string
	for _, line := range strings.Split(source, "\n") {
		trimmed := strings.TrimSpace(line)
		if strings.HasPrefix(trimmed, "DELIMITER ") {
			delimiter = strings.TrimSpace(strings.TrimPrefix(trimmed, "DELIMITER "))
			if delimiter == "" {
				return nil, fmt.Errorf("empty SQL delimiter")
			}
			continue
		}
		if buffer.Len() == 0 && (trimmed == "" || strings.HasPrefix(trimmed, "--")) {
			continue
		}
		buffer.WriteString(line)
		buffer.WriteByte('\n')
		if strings.HasSuffix(trimmed, delimiter) {
			statement := strings.TrimSuffix(strings.TrimSpace(buffer.String()), delimiter)
			statements = append(statements, statement)
			buffer.Reset()
		}
	}
	if strings.TrimSpace(buffer.String()) != "" {
		return nil, fmt.Errorf("unterminated SQL script")
	}
	return statements, nil
}

func CleanupTables() []string {
	block := regexp.MustCompile(`(?s)INSERT INTO _sw_cleanup_targets_20261106\([^\n]+\) VALUES\s*(.*?);`).FindStringSubmatch(cleanupSQL)
	if len(block) != 2 {
		panic("cleanup table manifest is missing")
	}
	var names []string
	for _, match := range regexp.MustCompile(`\('([a-z0-9_]+)'`).FindAllStringSubmatch(block[1], -1) {
		names = append(names, match[1])
	}
	return names
}

func LegacyArchives() map[string]string {
	archives := map[string]string{}
	for _, match := range regexp.MustCompile("`([a-z0-9_]+)` TO `(legacy_sw_20261103_[a-z0-9_]+)`").FindAllStringSubmatch(frameworkSQL, -1) {
		archives[match[1]] = match[2]
	}
	return archives
}

func FrameworkCreatedTables() []string {
	var names []string
	for _, match := range regexp.MustCompile("(?m)^CREATE TABLE `?([a-z0-9_]+)`? ").FindAllStringSubmatch(frameworkSQL, -1) {
		names = append(names, match[1])
	}
	return names
}