package main

import (
	"context"
	"fmt"
	"log/slog"
	"math/rand"
	"os"
	"time"

	"git.sr.ht/~ashkeel/containers/sync"
	slogmulti "github.com/samber/slog-multi"
	"gopkg.in/natefinch/lumberjack.v2"
)

const LogHistory = 50

var (
	lastLogs     *sync.Slice[LogEntry]
	incomingLogs chan LogEntry
)

func initLogger(level slog.Level) {
	lastLogs = sync.NewSlice[LogEntry]()
	incomingLogs = make(chan LogEntry, 100)
	logStorage := NewLogStorage(level)
	fileLogger := &lumberjack.Logger{
		Filename:   logFilename,
		MaxSize:    20,
		MaxBackups: 3,
		MaxAge:     28,
	}
	consoleHandler := slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
		Level: level,
	})
	fileHandler := slog.NewJSONHandler(fileLogger, &slog.HandlerOptions{
		AddSource: true,
		Level:     level,
	})
	logger := slog.New(slogmulti.Fanout(consoleHandler, fileHandler, logStorage))

	slog.SetDefault(logger)
}

type LogEntry struct {
	ID      string `json:"id"`
	Time    string `json:"time"`
	Level   string `json:"level"`
	Message string `json:"message"`
	Data    string `json:"data"`
}

type LogStorage struct {
	minLevel slog.Level
	attrs    []slog.Attr
	group    string
}

func (core *LogStorage) Enabled(_ context.Context, level slog.Level) bool {
	return level >= core.minLevel
}

func (core *LogStorage) Handle(_ context.Context, record slog.Record) error {
	attributes := map[string]any{}
	record.Attrs(func(attrs slog.Attr) bool {
		attributes[attrs.Key] = attrs.Value.Any()
		return true
	})
	attrJSON, _ := json.MarshalToString(attributes)

	// Generate unique log ID
	id := fmt.Sprintf("%d-%d", time.Now().UnixNano(), rand.Int31())

	logEntry := LogEntry{
		ID:      id,
		Time:    record.Time.Format(time.RFC3339),
		Level:   record.Level.String(),
		Message: record.Message,
		Data:    attrJSON,
	}
	lastLogs.Push(logEntry)
	if lastLogs.Size() > LogHistory {
		lastLogs.Splice(0, 1)
	}
	incomingLogs <- logEntry
	return nil
}

func (core *LogStorage) WithAttrs(attrs []slog.Attr) slog.Handler {
	return &LogStorage{
		minLevel: core.minLevel,
		attrs:    append(core.attrs, attrs...),
		group:    core.group,
	}
}

func (core *LogStorage) WithGroup(name string) slog.Handler {
	return &LogStorage{
		minLevel: core.minLevel,
		attrs:    core.attrs,
		group:    name,
	}
}

func NewLogStorage(level slog.Level) *LogStorage {
	return &LogStorage{
		minLevel: level,
	}
}

func parseLogFields(data map[string]any) []any {
	fields := []any{}
	for k, v := range data {
		fields = append(fields, k, v)
	}
	return fields
}