package fingerprint

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

// Zig panic/stack trace patterns:
//   /path/to/file.zig:42:13: 0x1234 in function_name (module)
//   ???:?:?: 0x1234 in ??? (???)
var zigFrameRe = regexp.MustCompile(
	`^\s*(.+?):(\d+):\d+:\s+(0x[0-9a-fA-F]+)\s+in\s+(\S+)\s+\(([^)]*)\)`,
)

// Zig panic header: "panic: ..." or "thread N panic: ..."
var zigPanicRe = regexp.MustCompile(`(?:thread \d+ )?panic: `)

// ParseZig parses Zig panic stack traces.
func ParseZig(raw string) []Frame {
	if !zigPanicRe.MatchString(raw) && !strings.Contains(raw, " in ") {
		return nil
	}

	var frames []Frame
	for _, line := range strings.Split(raw, "\n") {
		m := zigFrameRe.FindStringSubmatch(line)
		if m == nil {
			continue
		}

		file := m[1]
		lineNo, _ := strconv.Atoi(m[2])
		addr := m[3]
		fn := m[4]
		module := m[5]

		// Skip unknown frames.
		if fn == "???" {
			continue
		}

		frames = append(frames, Frame{
			Address:  addr,
			Function: fn,
			File:     file,
			Line:     lineNo,
			Module:   module,
			Index:    len(frames),
		})
	}

	if len(frames) < 1 {
		return nil
	}

	return frames
}