// Package logging configures the application's structured logger.
package logging

import (
	"os"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/rs/zerolog"
)

// New builds a zerolog logger for the given level and format.
//
// level is one of: trace, debug, info, warn, error, fatal, panic.
// format is "json" for machine-readable output, anything else produces a
// human-friendly console output (useful for local development).
func New(level, format, environment string) zerolog.Logger {
	lvl, err := zerolog.ParseLevel(strings.ToLower(strings.TrimSpace(level)))
	if err != nil || lvl == zerolog.NoLevel {
		lvl = zerolog.InfoLevel
	}

	var writer zerolog.LevelWriter
	if strings.EqualFold(format, "json") {
		writer = zerolog.MultiLevelWriter(os.Stdout)
	} else {
		console := zerolog.ConsoleWriter{Out: os.Stdout, TimeFormat: time.RFC3339}
		writer = zerolog.MultiLevelWriter(console)
	}

	logger := zerolog.New(writer).
		Level(lvl).
		With().
		Timestamp().
		Str("service", "kereru-forms").
		Str("environment", environment).
		Logger()

	zerolog.SetGlobalLevel(lvl)
	return logger
}

// GinMiddleware logs every HTTP request with useful observability fields.
func GinMiddleware(logger zerolog.Logger) gin.HandlerFunc {
	return func(c *gin.Context) {
		start := time.Now()
		path := c.Request.URL.Path
		if raw := c.Request.URL.RawQuery; raw != "" {
			path = path + "?" + raw
		}

		c.Next()

		event := logger.Info()
		if c.Writer.Status() >= 500 {
			event = logger.Error()
		} else if c.Writer.Status() >= 400 {
			event = logger.Warn()
		}

		event.
			Str("method", c.Request.Method).
			Str("path", path).
			Int("status", c.Writer.Status()).
			Dur("latency", time.Since(start)).
			Str("client_ip", c.ClientIP()).
			Str("user_agent", c.Request.UserAgent()).
			Str("request_id", RequestID(c)).
			Msg("http request")
	}
}

const requestIDKey = "request_id"

// RequestID returns the correlation id assigned to the current request.
func RequestID(c *gin.Context) string {
	if v, ok := c.Get(requestIDKey); ok {
		if s, ok := v.(string); ok {
			return s
		}
	}
	return ""
}

// SetRequestID stores the correlation id on the context.
func SetRequestID(c *gin.Context, id string) {
	c.Set(requestIDKey, id)
}