package plugin

import (
	"bufio"
	"bytes"
	"strings"

	"golang.org/x/mod/semver"
)

// ParseModVersion extracts the version string from an embedded plugin.mod file.
// Returns "0.0.0" if parsing fails or version is not found.
func ParseModVersion(data []byte) string {
	scanner := bufio.NewScanner(bytes.NewReader(data))
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if strings.HasPrefix(line, "version") {
			parts := strings.SplitN(line, "=", 2)
			if len(parts) != 2 {
				continue
			}
			val := strings.TrimSpace(parts[1])
			val = strings.Trim(val, `"`)
			if val != "" {
				return val
			}
		}
	}
	return "0.0.0"
}

// CompareVersions compares two semver strings.
// Returns -1 if v1 < v2, 0 if equal, +1 if v1 > v2.
// Returns 0 if either version is invalid.
func CompareVersions(v1, v2 string) int {
	if !strings.HasPrefix(v1, "v") {
		v1 = "v" + v1
	}
	if !strings.HasPrefix(v2, "v") {
		v2 = "v" + v2
	}
	if !semver.IsValid(v1) || !semver.IsValid(v2) {
		return 0
	}
	return semver.Compare(v1, v2)
}