package main

import (
	"bytes"
	"crypto/aes"
	"crypto/sha256"
	"encoding/base64"
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"net/http"
	"os"
	"strings"
	"time"

	"inou/lib"
)

const (
	baseURL = "https://cloud.renpho.com"
	aesKey  = "ed*wijdi$h6fe3ew"
)

// Renpho API response
type apiResponse struct {
	Code int             `json:"code"`
	Msg  string          `json:"msg"`
	Data json.RawMessage `json:"data"`
}

// Login response
type loginUser struct {
	UserID string `json:"id"`
	Token  string `json:"terminal_user_session_key"`
	Email  string `json:"email"`
}

// Table mapping
type tableMapping struct {
	UserID    string `json:"user_id"`
	TableName string `json:"table_name"`
}

// Measurement from Renpho
type measurement struct {
	TimeStamp   int64   `json:"time_stamp"`
	Weight      float64 `json:"weight"`
	BodyFat     float64 `json:"bodyfat"`
	Water       float64 `json:"water"`
	BMR         float64 `json:"bmr"`
	BodyAge     float64 `json:"bodyage"`
	Muscle      float64 `json:"muscle"`
	Bone        float64 `json:"bone"`
	SubFat      float64 `json:"subfat"`
	VisFat      float64 `json:"visfat"`
	BMI         float64 `json:"bmi"`
	Protein     float64 `json:"protein"`
	FatFree     float64 `json:"fat_free_weight"`
	Sinew       float64 `json:"sinew"`
	UserID      string  `json:"internal_model"`
}

// Account config stored in Renpho dossier's Data field
type renphoConfig struct {
	Accounts []renphoAccount `json:"renpho_accounts"`
}

type renphoAccount struct {
	Email     string            `json:"email"`
	Password  string            `json:"password"`
	DossierID string            `json:"dossier_id"`    // inou dossier to write vitals to
	UserMap   map[string]string `json:"user_map"`      // renpho userID → inou dossierID (for multi-user scales)
}

// Runtime state for an authenticated session
type session struct {
	token string
}

func main() {
	setup := flag.Bool("setup", false, "Create Renpho system dossier and configure accounts")
	discover := flag.Bool("discover", false, "Login and show Renpho user IDs for mapping")
	flag.Parse()

	if err := lib.Init(); err != nil {
		fatal("lib.Init: %v", err)
	}

	if *setup {
		runSetup()
		return
	}

	if *discover {
		runDiscover()
		return
	}

	renphoID, cfg, err := loadConfig()
	if err != nil {
		fatal("load config: %v", err)
	}

	if len(cfg.Accounts) == 0 {
		fmt.Println("No Renpho accounts configured. Run with -setup first.")
		return
	}

	importID := lib.NextImportID()

	for _, acct := range cfg.Accounts {
		fmt.Printf("=== %s ===\n", acct.Email)
		if err := syncAccount(renphoID, &acct, importID); err != nil {
			fmt.Printf("  ERROR: %v\n", err)
		}
	}
}

// runSetup creates the Renpho system dossier with config from stdin
func runSetup() {
	// Check if already exists
	entries, err := lib.EntryRead("", "", &lib.Filter{Category: 0})
	if err != nil {
		fatal("list dossiers: %v", err)
	}
	for _, e := range entries {
		if strings.EqualFold(e.SearchKey, "renpho") {
			fmt.Printf("Renpho dossier already exists: %s\n", e.EntryID)
			fmt.Println("Current config:")
			fmt.Println(e.Data)
			return
		}
	}

	// Read config JSON from stdin
	fmt.Println("Paste renpho_accounts JSON (or empty for blank), then Ctrl+D:")
	data, _ := io.ReadAll(os.Stdin)
	configJSON := strings.TrimSpace(string(data))

	// Validate if non-empty
	if configJSON != "" {
		var cfg renphoConfig
		if err := json.Unmarshal([]byte(configJSON), &cfg); err != nil {
			fatal("invalid JSON: %v", err)
		}
	} else {
		configJSON = `{"renpho_accounts":[]}`
	}

	id := lib.NewID()
	err = lib.EntryWrite("", &lib.Entry{
		EntryID:   id,
		DossierID: id,
		Category:  0,
		Type:      "dossier",
		Summary:   "Renpho",
		SearchKey: "renpho",
		Data:      configJSON,
		Timestamp: time.Now().Unix(),
	})
	if err != nil {
		fatal("create dossier: %v", err)
	}
	fmt.Printf("Created Renpho dossier: %s\n", id)
}

// runDiscover logs into Renpho and shows user IDs + table mappings
func runDiscover() {
	if flag.NArg() < 2 {
		fmt.Println("Usage: import-renpho -discover <email> <password>")
		os.Exit(1)
	}
	email, password := flag.Arg(0), flag.Arg(1)

	s, user, err := login(email, password)
	if err != nil {
		fatal("login: %v", err)
	}
	fmt.Printf("Logged in: %s (user ID: %s)\n", user.Email, user.UserID)

	tables, err := getTableMappings(s)
	if err != nil {
		fatal("table mappings: %v", err)
	}
	fmt.Println("\nUser → Table mappings:")
	for _, t := range tables {
		fmt.Printf("  user_id: %s  table: %s\n", t.UserID, t.TableName)

		// Fetch a sample measurement to show what user this is
		ms, err := fetchMeasurements(s, t.UserID, t.TableName)
		if err == nil && len(ms) > 0 {
			fmt.Printf("    %d measurements, latest weight: %.1f kg\n", len(ms), ms[0].Weight)
		}
	}
}

// loadConfig reads the Renpho system dossier and its config from Data field
func loadConfig() (string, *renphoConfig, error) {
	// Find Renpho dossier by searching for email="renpho" in cat=0
	entries, err := lib.EntryRead("", "", &lib.Filter{Category: 0})
	if err != nil {
		return "", nil, fmt.Errorf("list dossiers: %v", err)
	}

	for _, e := range entries {
		if strings.EqualFold(e.SearchKey, "renpho") {
			var cfg renphoConfig
			if e.Data != "" {
				if err := json.Unmarshal([]byte(e.Data), &cfg); err != nil {
					return "", nil, fmt.Errorf("parse config: %v", err)
				}
			}
			return e.EntryID, &cfg, nil
		}
	}

	return "", nil, fmt.Errorf("no Renpho system dossier found (create a dossier with SearchKey='renpho')")
}

func syncAccount(renphoID string, acct *renphoAccount, importID int64) error {
	// Login
	s, user, err := login(acct.Email, acct.Password)
	if err != nil {
		return fmt.Errorf("login: %v", err)
	}
	fmt.Printf("  Logged in as %s (user %s)\n", user.Email, user.UserID)

	// Get table mappings
	tables, err := getTableMappings(s)
	if err != nil {
		return fmt.Errorf("table mappings: %v", err)
	}

	for _, t := range tables {
		dossierID := acct.DossierID
		if acct.UserMap != nil {
			if mapped, ok := acct.UserMap[t.UserID]; ok {
				dossierID = mapped
			}
		}
		if dossierID == "" {
			fmt.Printf("  Skipping user %s (no dossier mapped)\n", t.UserID)
			continue
		}

		// Ensure Renpho has write access to this dossier
		if !lib.CheckAccess(renphoID, dossierID, "", lib.PermWrite) {
			fmt.Printf("  Granting Renpho access to %s\n", dossierID)
			if err := lib.GrantAccess(dossierID, renphoID, dossierID, lib.PermRead|lib.PermWrite, 0); err != nil {
				return fmt.Errorf("grant access to %s: %v", dossierID, err)
			}
		}

		measurements, err := fetchMeasurements(s, t.UserID, t.TableName)
		if err != nil {
			fmt.Printf("  Table %s: %v\n", t.TableName, err)
			continue
		}
		fmt.Printf("  Table %s: %d measurements for dossier %s\n", t.TableName, len(measurements), dossierID)

		created, skipped, err := writeMeasurements(renphoID, dossierID, measurements, importID)
		if err != nil {
			fmt.Printf("  Write error: %v\n", err)
			continue
		}
		fmt.Printf("  Created %d, skipped %d\n", created, skipped)
	}
	return nil
}

func login(email, password string) (*session, *loginUser, error) {
	body := map[string]string{"email": email, "password": password}
	resp, err := apiCall(nil, "RenphoHealth/centerUser/loginUser", body)
	if err != nil {
		return nil, nil, err
	}
	if resp.Code != 101 {
		return nil, nil, fmt.Errorf("code %d: %s", resp.Code, resp.Msg)
	}
	var user loginUser
	if err := json.Unmarshal(resp.Data, &user); err != nil {
		return nil, nil, fmt.Errorf("parse login: %v", err)
	}
	return &session{token: user.Token}, &user, nil
}

func getTableMappings(s *session) ([]tableMapping, error) {
	resp, err := apiCall(s, "RenphoHealth/scale/getUserIdMappingTableNames", map[string]string{})
	if err != nil {
		return nil, err
	}
	if resp.Code != 101 {
		return nil, fmt.Errorf("code %d: %s", resp.Code, resp.Msg)
	}
	var tables []tableMapping
	if err := json.Unmarshal(resp.Data, &tables); err != nil {
		return nil, err
	}
	return tables, nil
}

func fetchMeasurements(s *session, userID, tableName string) ([]measurement, error) {
	userIDs, _ := json.Marshal([]string{userID})
	body := map[string]any{
		"pageNum":   1,
		"pageSize":  "200",
		"userIds":   string(userIDs),
		"tableName": tableName,
	}
	resp, err := apiCall(s, "RenphoHealth/scale/queryAllMeasureDataList/", body)
	if err != nil {
		return nil, err
	}
	if resp.Code != 101 {
		return nil, fmt.Errorf("code %d: %s", resp.Code, resp.Msg)
	}
	var ms []measurement
	if err := json.Unmarshal(resp.Data, &ms); err != nil {
		return nil, err
	}
	return ms, nil
}

// writeMeasurements converts Renpho data to inou vital entries
func writeMeasurements(renphoID, dossierID string, ms []measurement, importID int64) (int, int, error) {
	created, skipped := 0, 0

	// Ensure category root
	rootID, err := ensureRoot(renphoID, dossierID)
	if err != nil {
		return 0, 0, err
	}

	// Metric definitions: field name → (unit, label)
	type metricDef struct {
		unit  string
		label string
	}
	metrics := []struct {
		name string
		def  metricDef
		get  func(m *measurement) float64
	}{
		{"weight", metricDef{"kg", "Weight"}, func(m *measurement) float64 { return m.Weight }},
		{"body_fat", metricDef{"%", "Body Fat"}, func(m *measurement) float64 { return m.BodyFat }},
		{"water", metricDef{"%", "Water"}, func(m *measurement) float64 { return m.Water }},
		{"bmr", metricDef{"kcal", "BMR"}, func(m *measurement) float64 { return m.BMR }},
		{"body_age", metricDef{"years", "Body Age"}, func(m *measurement) float64 { return m.BodyAge }},
		{"muscle", metricDef{"%", "Muscle"}, func(m *measurement) float64 { return m.Muscle }},
		{"bone", metricDef{"kg", "Bone Mass"}, func(m *measurement) float64 { return m.Bone }},
		{"subcutaneous_fat", metricDef{"%", "Subcutaneous Fat"}, func(m *measurement) float64 { return m.SubFat }},
		{"visceral_fat", metricDef{"", "Visceral Fat"}, func(m *measurement) float64 { return m.VisFat }},
		{"bmi", metricDef{"", "BMI"}, func(m *measurement) float64 { return m.BMI }},
		{"protein", metricDef{"%", "Protein"}, func(m *measurement) float64 { return m.Protein }},
		{"fat_free_weight", metricDef{"kg", "Fat Free Weight"}, func(m *measurement) float64 { return m.FatFree }},
		{"skeletal_muscle", metricDef{"%", "Skeletal Muscle"}, func(m *measurement) float64 { return m.Sinew }},
	}

	groups := map[string]string{} // metric name → groupID

	for _, m := range ms {
		ts := m.TimeStamp
		if ts == 0 {
			continue
		}
		// Renpho timestamps are in seconds
		if ts > 1e12 {
			ts = ts / 1000 // convert millis to seconds if needed
		}

		for _, met := range metrics {
			val := met.get(&m)
			if val == 0 {
				continue
			}

			// Ensure group
			groupID, ok := groups[met.name]
			if !ok {
				groupID, err = ensureGroup(renphoID, dossierID, rootID, met.name, met.def.unit, met.def.label)
				if err != nil {
					return created, skipped, fmt.Errorf("group %s: %v", met.name, err)
				}
				groups[met.name] = groupID
			}

			// Dedup: check for existing reading at same timestamp in same group
			existing, _ := lib.EntryRead(renphoID, dossierID, &lib.Filter{
				Category: lib.CategoryVital,
				Type:     "reading",
				ParentID: groupID,
				FromDate: ts,
				ToDate:   ts + 1,
			})
			if len(existing) > 0 {
				skipped++
				continue
			}

			valueStr := fmt.Sprintf("%g", val)
			summary := valueStr
			if met.def.unit != "" {
				summary += " " + met.def.unit
			}
			data, _ := json.Marshal(map[string]string{"unit": met.def.unit, "source": "renpho"})

			reading := &lib.Entry{
				DossierID: dossierID,
				ParentID:  groupID,
				Category:  lib.CategoryVital,
				Type:      "reading",
				Value:     valueStr,
				Summary:   summary,
				Timestamp: ts,
				Data:      string(data),
				Import:    importID,
			}
			if err := lib.EntryWrite(renphoID, reading); err != nil {
				return created, skipped, fmt.Errorf("write %s@%d: %v", met.name, ts, err)
			}
			created++
		}
	}

	return created, skipped, nil
}

func ensureRoot(accessorID, dossierID string) (string, error) {
	entries, err := lib.EntryRead(accessorID, dossierID, &lib.Filter{
		Category: lib.CategoryVital,
		Type:     "root",
		ParentID: dossierID,
	})
	if err != nil {
		return "", err
	}
	if len(entries) > 0 {
		return entries[0].EntryID, nil
	}
	id := deterministicID(dossierID, "cat", fmt.Sprintf("%d", lib.CategoryVital))
	err = lib.EntryWrite(accessorID, &lib.Entry{
		EntryID:   id,
		DossierID: dossierID,
		ParentID:  dossierID,
		Category:  lib.CategoryVital,
		Type:      "root",
	})
	return id, err
}

func ensureGroup(accessorID, dossierID, rootID, metric, unit, label string) (string, error) {
	entries, err := lib.EntryRead(accessorID, dossierID, &lib.Filter{
		Category: lib.CategoryVital,
		Type:     metric,
		ParentID: rootID,
	})
	if err != nil {
		return "", err
	}
	if len(entries) > 0 {
		return entries[0].EntryID, nil
	}
	id := deterministicID(dossierID, "group", fmt.Sprintf("%d", lib.CategoryVital), metric)
	data, _ := json.Marshal(map[string]string{"unit": unit, "source": "renpho"})
	err = lib.EntryWrite(accessorID, &lib.Entry{
		EntryID:   id,
		DossierID: dossierID,
		ParentID:  rootID,
		Category:  lib.CategoryVital,
		Type:      metric,
		Summary:   label,
		Data:      string(data),
	})
	return id, err
}

func deterministicID(parts ...string) string {
	h := sha256.Sum256([]byte(strings.Join(parts, ":")))
	return fmt.Sprintf("%016x", h[:8])
}

// ============================================================================
// Renpho API client
// ============================================================================

func apiCall(s *session, path string, body any) (*apiResponse, error) {
	bodyJSON, err := json.Marshal(body)
	if err != nil {
		return nil, err
	}

	encrypted := aesEncrypt(bodyJSON)
	wrapper, _ := json.Marshal(map[string]string{"encryptData": encrypted})

	req, err := http.NewRequest("POST", baseURL+"/"+path, bytes.NewReader(wrapper))
	if err != nil {
		return nil, err
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	req.Header.Set("timeZone", "+1")
	req.Header.Set("language", "2")
	req.Header.Set("appVersion", "5.18.3")
	req.Header.Set("platform", "2")
	req.Header.Set("systemVersion", "14")
	req.Header.Set("phone", "import-renpho")
	req.Header.Set("languageCode", "en")
	req.Header.Set("area", "0")
	if s != nil {
		req.Header.Set("token", s.token)
	}

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != 200 {
		return nil, fmt.Errorf("HTTP %d: %s", resp.StatusCode, string(data))
	}

	// Outer response is plain JSON with encrypted data field
	var outer struct {
		Code int             `json:"code"`
		Msg  string          `json:"msg"`
		Data json.RawMessage `json:"data"`
	}
	if err := json.Unmarshal(data, &outer); err != nil {
		return nil, fmt.Errorf("parse response: %v (%s)", err, string(data))
	}

	result := &apiResponse{Code: outer.Code, Msg: outer.Msg}

	// Data field is a quoted base64 AES-encrypted string
	if len(outer.Data) > 2 && outer.Data[0] == '"' {
		var encStr string
		json.Unmarshal(outer.Data, &encStr)
		if encStr != "" {
			decrypted := aesDecrypt(encStr)
			if decrypted != nil {
				result.Data = decrypted
			}
		}
	} else {
		result.Data = outer.Data
	}

	return result, nil
}

// ============================================================================
// AES-128/ECB/PKCS5 — matches Renpho's com.renpho.module.utils.AESUtil
// ============================================================================

func aesEncrypt(plaintext []byte) string {
	block, _ := aes.NewCipher([]byte(aesKey))
	padded := pkcs5Pad(plaintext, aes.BlockSize)
	out := make([]byte, len(padded))
	for i := 0; i < len(padded); i += aes.BlockSize {
		block.Encrypt(out[i:i+aes.BlockSize], padded[i:i+aes.BlockSize])
	}
	return base64.StdEncoding.EncodeToString(out)
}

func aesDecrypt(b64 string) []byte {
	data, err := base64.StdEncoding.DecodeString(b64)
	if err != nil {
		return nil
	}
	block, err := aes.NewCipher([]byte(aesKey))
	if err != nil {
		return nil
	}
	if len(data)%aes.BlockSize != 0 {
		return nil
	}
	out := make([]byte, len(data))
	for i := 0; i < len(data); i += aes.BlockSize {
		block.Decrypt(out[i:i+aes.BlockSize], data[i:i+aes.BlockSize])
	}
	return pkcs5Unpad(out)
}

func pkcs5Pad(data []byte, blockSize int) []byte {
	padding := blockSize - len(data)%blockSize
	pad := bytes.Repeat([]byte{byte(padding)}, padding)
	return append(data, pad...)
}

func pkcs5Unpad(data []byte) []byte {
	if len(data) == 0 {
		return nil
	}
	padding := int(data[len(data)-1])
	if padding > len(data) || padding > aes.BlockSize {
		return data
	}
	return data[:len(data)-padding]
}

func fatal(format string, args ...any) {
	fmt.Printf("FATAL: "+format+"\n", args...)
	panic("abort")
}