package main

import (
	"context"
	"strings"

	"github.com/labstack/echo/v4"
	"go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc"
	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp"
	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
	"go.opentelemetry.io/otel/log/global"
	"go.opentelemetry.io/otel/sdk/log"
	"go.opentelemetry.io/otel/sdk/metric"
	"go.opentelemetry.io/otel/sdk/resource"
	"go.opentelemetry.io/otel/sdk/trace"
	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
)

func setupOtel(e *echo.Echo) (func(), error) {
	ctx := context.Background()
	proto := GetenvOr("OTEL_EXPORTER_OTLP_PROTOCOL", "http/protobuf")

	res, err := resource.New(
		ctx,
		resource.WithAttributes(semconv.ServiceNameKey.String("kyoo.auth")),
		resource.WithFromEnv(),
		resource.WithTelemetrySDK(),
		resource.WithProcess(),
		resource.WithOS(),
		resource.WithContainer(),
		resource.WithHost(),
	)
	if err != nil {
		return nil, err
	}

	var le log.Exporter
	if proto == "http/protobuf" {
		le, err = otlploghttp.New(ctx)
	} else {
		le, err = otlploggrpc.New(ctx)
	}
	if err != nil {
		return nil, err
	}
	lp := log.NewLoggerProvider(
		log.WithProcessor(log.NewBatchProcessor(le)),
		log.WithResource(res),
	)
	global.SetLoggerProvider(lp)

	var me metric.Exporter
	if proto == "http/protobuf" {
		me, err = otlpmetrichttp.New(ctx)
	} else {
		me, err = otlpmetricgrpc.New(ctx)
	}
	if err != nil {
		return func() {}, err
	}
	mp := metric.NewMeterProvider(
		metric.WithReader(
			metric.NewPeriodicReader(me),
		),
		metric.WithResource(res),
	)
	otel.SetMeterProvider(mp)

	var te *otlptrace.Exporter
	if proto == "http/protobuf" {
		te, err = otlptracehttp.New(ctx)
	} else {
		te, err = otlptracegrpc.New(ctx)
	}
	if err != nil {
		return func() {}, err
	}
	tp := trace.NewTracerProvider(
		trace.WithBatcher(te),
		trace.WithResource(res),
	)
	otel.SetTracerProvider(tp)

	e.Use(otelecho.Middleware("kyoo.auth", otelecho.WithSkipper(func(c echo.Context) bool {
		return c.Path() == "/auth/health" || c.Path() == "/auth/ready"
	})))

	return func() {
		lp.Shutdown(ctx)
		mp.Shutdown(ctx)
		tp.Shutdown(ctx)
	}, nil
}

// stolen from https://github.com/exaring/otelpgx/issues/47
func dbGetSpanName(sql string) string {
	if len(sql) >= 10 && sql[0:9] == "-- name: " {
		// -- name: {name} :{type}
		if index := strings.Index(sql[9:], ":"); index != -1 {
			// remove leading space before :
			// optimised assuming this comment has been generated by SQLC
			return sql[9 : 9+(index-1)]
		}
		// -- name: {name}
		if index := strings.Index(sql[9:], "\n"); index != -1 {
			if sql[len(sql[9:9+index])-1] != ' ' {
				return sql[9 : 9+index]
			}
			return strings.TrimSpace(sql[9 : 9+index])
		}
	}

	if len(sql) >= 9 && sql[0:8] == "-- name:" {
		// -- name:{name}
		if index := strings.Index(sql[8:], "\n"); index != -1 {
			if sql[len(sql[8:8+index])-1] != ' ' {
				return sql[8 : 8+index]
			}
			return strings.TrimSpace(sql[8 : 8+index])
		}
	}

	if len(sql) >= 8 && sql[0:7] == "--name:" {
		// -- name:{name}
		if index := strings.Index(sql[7:], "\n"); index != -1 {
			if sql[len(sql[7:7+index])-1] != ' ' {
				return sql[7 : 7+index]
			}
			return strings.TrimSpace(sql[7 : 7+index])
		}
	}

	return sql
}