// Parses log/bmc/commer-comp/*, per-component BMC transcripts (slot presence,
// HGX management controller, switch VR/power, switch CPLD). Each rotated log
// (component.log plus component.tar.gz.0..9) uses the same
// "[timestamp][file, line][level] message" line format.
package inspur

import (
	"archive/tar"
	"bufio"
	"bytes"
	"compress/gzip"
	"fmt"
	"io"
	"regexp"
	"strings"
	"time"

	"git.mchus.pro/mchus/logpile/internal/models"
	"git.mchus.pro/mchus/logpile/internal/parser"
)

var commerCompComponents = []string{"commerslot", "commerhmc", "commerswvr", "commerswcpld"}

var commerCompLineRegex = regexp.MustCompile(`^\[(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2})\]\[[^\]]*\]\[(\w+)\]\s*(.+)$`)

var commerCompNoisePatterns = []*regexp.Regexp{
	regexp.MustCompile(`(?i)invalid comp data`),
	regexp.MustCompile(`(?i)error in update redis`),
	regexp.MustCompile(`(?i)mutextimeout\s*=\s*0`),
}

var commerCompFailureRegex = regexp.MustCompile(`(?i)\b(fail|failed|failure|error)\b`)

// ParseCommerCompEvents extracts BMC component failure events from
// log/bmc/commer-comp/<component>/ logs, including rotated *.tar.gz.N parts.
func ParseCommerCompEvents(files []parser.ExtractedFile, location *time.Location) []models.Event {
	var events []models.Event
	for _, f := range files {
		path := strings.ToLower(f.Path)
		if !strings.Contains(path, "/commer-comp/") {
			continue
		}
		component := commerCompComponentFromPath(path)
		if component == "" {
			continue
		}

		if strings.Contains(path, ".tar.gz") {
			for _, part := range decodeNestedTarGz(f.Content) {
				events = append(events, parseCommerCompLog(part, component, location)...)
			}
			continue
		}
		if !strings.HasSuffix(path, ".log") {
			continue
		}
		events = append(events, parseCommerCompLog(f.Content, component, location)...)
	}
	return events
}

func commerCompComponentFromPath(path string) string {
	for _, c := range commerCompComponents {
		if strings.Contains(path, "/"+c+"/") {
			return c
		}
	}
	return ""
}

// decodeNestedTarGz unpacks a rotated log part (a full tar.gz archive stored
// as e.g. commerhmc.tar.gz.0) and returns the contents of every regular file
// inside it.
func decodeNestedTarGz(content []byte) [][]byte {
	gz, err := gzip.NewReader(bytes.NewReader(content))
	if err != nil {
		return nil
	}
	defer gz.Close()

	tr := tar.NewReader(gz)
	var out [][]byte
	for {
		hdr, err := tr.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			break
		}
		if hdr.Typeflag != tar.TypeReg {
			continue
		}
		buf, err := io.ReadAll(tr)
		if err != nil {
			continue
		}
		out = append(out, buf)
	}
	return out
}

func parseCommerCompLog(content []byte, component string, location *time.Location) []models.Event {
	var events []models.Event
	scanner := bufio.NewScanner(bytes.NewReader(content))
	scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024)

	for scanner.Scan() {
		line := scanner.Text()
		m := commerCompLineRegex.FindStringSubmatch(line)
		if m == nil {
			continue
		}
		msg := strings.TrimSpace(m[3])
		if isCommerCompNoise(msg) || !commerCompFailureRegex.MatchString(msg) {
			continue
		}

		ts, err := time.ParseInLocation("2006-01-02 15:04:05", m[1], location)
		if err != nil {
			continue
		}

		events = append(events, models.Event{
			ID:          fmt.Sprintf("commer_comp_%s_%d_%s", component, ts.Unix(), commerCompIDSuffix(msg)),
			Timestamp:   ts,
			Source:      fmt.Sprintf("BMC/%s", component),
			SensorType:  "bmc_component",
			EventType:   m[2],
			Severity:    commerCompSeverity(m[2]),
			Description: msg,
			RawData:     line,
		})
	}
	return events
}

func isCommerCompNoise(msg string) bool {
	for _, re := range commerCompNoisePatterns {
		if re.MatchString(msg) {
			return true
		}
	}
	return false
}

var commerCompNonAlnumRegex = regexp.MustCompile(`[^a-zA-Z0-9]+`)

// commerCompIDSuffix derives a short, stable suffix from the message so that
// two different failures logged in the same second get distinct event IDs.
func commerCompIDSuffix(msg string) string {
	s := commerCompNonAlnumRegex.ReplaceAllString(strings.ToLower(msg), "_")
	s = strings.Trim(s, "_")
	if len(s) > 40 {
		s = s[:40]
	}
	return s
}

func commerCompSeverity(level string) models.Severity {
	switch strings.ToLower(level) {
	case "critial", "critical", "error":
		return models.SeverityCritical
	case "warning", "warn":
		return models.SeverityWarning
	default:
		return models.SeverityInfo
	}
}