package api

import (
	"encoding/json"

	"geniusrun/backend/internal/store"
)

// activityResponse adds back ActivityName/ActivityType as fields decoded
// from RawJSON. They're no longer stored as their own columns (Phase 2 of
// the 2026-07 duplication cleanup -- see store.Activity's doc comment):
// Garmin's raw JSON is the only place they live now, decoded fresh for each
// API response instead of kept as a redundant copy in the database.
type activityResponse struct {
	store.Activity
	ActivityName string `json:"ActivityName"`
	ActivityType string `json:"ActivityType"`
}

func toActivityResponse(a store.Activity) activityResponse {
	name, typeKey := decodeActivityDisplayFields(a.RawJSON)
	return activityResponse{Activity: a, ActivityName: name, ActivityType: typeKey}
}

type rawActivityDisplayFields struct {
	ActivityName string `json:"activityName"`
	ActivityType struct {
		TypeKey string `json:"typeKey"`
	} `json:"activityType"`
}

func decodeActivityDisplayFields(rawJSON string) (name, typeKey string) {
	var f rawActivityDisplayFields
	_ = json.Unmarshal([]byte(rawJSON), &f) // best-effort -- zero values are fine if rawJSON is empty/malformed
	return f.ActivityName, f.ActivityType.TypeKey
}

// lapResponse adds back DurationSeconds/AvgHR as fields decoded from
// RawJSON, same rationale as activityResponse -- the frontend chart still
// needs them (x-axis timing, dashed average-HR line) even though nothing on
// the backend does.
type lapResponse struct {
	store.Lap
	DurationSeconds float64  `json:"DurationSeconds"`
	AvgHR           *float64 `json:"AvgHR"`
}

func toLapResponse(l store.Lap) lapResponse {
	duration, avgHR := decodeLapDisplayFields(l.RawJSON)
	return lapResponse{Lap: l, DurationSeconds: duration, AvgHR: avgHR}
}

func toLapResponses(laps []store.Lap) []lapResponse {
	out := make([]lapResponse, len(laps))
	for i, l := range laps {
		out[i] = toLapResponse(l)
	}
	return out
}

type rawLapDisplayFields struct {
	Duration  float64 `json:"duration"`
	AverageHR float64 `json:"averageHR"`
}

func decodeLapDisplayFields(rawJSON string) (durationSeconds float64, avgHR *float64) {
	var f rawLapDisplayFields
	_ = json.Unmarshal([]byte(rawJSON), &f)
	durationSeconds = f.Duration
	if f.AverageHR > 0 {
		v := f.AverageHR
		avgHR = &v
	}
	return
}