package fingerprint

import (
	"regexp"
	"strconv"
	"strings"
)

// Generic fallback patterns for common crash formats.
var (
	// "at function_name (file.c:42)" or "in function_name at file.c:42"
	genericAtRe = regexp.MustCompile(
		`(?:at|in)\s+(\S+)\s+(?:\()?([^:)\s]+):(\d+)`,
	)
	// "function_name+0x1234" (Linux kernel style, perf, etc.)
	genericOffsetRe = regexp.MustCompile(
		`^\s*(?:#\d+\s+)?(\S+)\+(0x[0-9a-fA-F]+)`,
	)
)

// ParseGeneric is a fallback parser that tries heuristic patterns.
func ParseGeneric(raw string) []Frame {
	var frames []Frame

	for _, line := range strings.Split(raw, "\n") {
		line = strings.TrimSpace(line)
		if line == "" {
			continue
		}

		if m := genericAtRe.FindStringSubmatch(line); m != nil {
			lineNo, _ := strconv.Atoi(m[3])
			frames = append(frames, Frame{
				Function: m[1],
				File:     m[2],
				Line:     lineNo,
				Index:    len(frames),
			})
			continue
		}

		if m := genericOffsetRe.FindStringSubmatch(line); m != nil {
			frames = append(frames, Frame{
				Function: m[1],
				Address:  m[2],
				Index:    len(frames),
			})
			continue
		}
	}

	if len(frames) < 2 {
		return nil
	}

	return frames
}