package api

import (
"bytes"
"compress/bzip2"
"encoding/base64"
"encoding/json"
"fmt"
"io"
"net/http"
"net/url"
"os"
"path/filepath"
"strings"
"time"
)

const (
baseURL      = "https://www.fuzzwork.co.uk/dump/latest"
tokenURL     = "https://login.eveonline.com/v2/oauth/token"
authURL      = "https://login.eveonline.com/v2/oauth/authorize"
redirectURI  = "https://localhost/callback/"
dataDirPath  = "../data"
authFilePath = "./cache/auth.json"
envFilePath  = "../../.env"
)

var scopes = []string{
"esi-assets.read_assets.v1",
"esi-location.read_location.v1",
"esi-location.read_online.v1",
"esi-wallet.read_character_wallet.v1",
"esi-ui.open_window.v1",
"esi-ui.write_waypoint.v1",
}

var requiredFiles = map[string]string{
"mapDenormalize.csv": fmt.Sprintf("%s/mapDenormalize.csv.bz2", baseURL),
"mapJumps.csv":       fmt.Sprintf("%s/mapJumps.csv.bz2", baseURL),
"invTypes.csv":       fmt.Sprintf("%s/invTypes.csv.bz2", baseURL),
"mapRegions.csv":     fmt.Sprintf("%s/mapRegions.csv.bz2", baseURL),
}

func StatusHandler(w http.ResponseWriter, r *http.Request) {
    // Check if data is ready
    dataReady := true
    for fileName := range requiredFiles {
        destPath := filepath.Join(dataDirPath, fileName)
        if _, err := os.Stat(destPath); err != nil {
            dataReady = false
            break
        }
    }

    // Check if auth is ready
    authReady := false
    if _, err := os.Stat(authFilePath); err == nil {
        authReady = true
    }

    w.Header().Set("Content-Type", "application/json")
    json.NewEncoder(w).Encode(map[string]bool{
        "data_ready": dataReady,
        "auth_ready": authReady,
    })
}

func DownloadDataHandler(w http.ResponseWriter, r *http.Request) {
if err := os.MkdirAll(dataDirPath, os.ModePerm); err != nil {
http.Error(w, fmt.Sprintf("Failed to create data dir: %v", err), http.StatusInternalServerError)
return
}

for fileName, downloadURL := range requiredFiles {
destPath := filepath.Join(dataDirPath, fileName)
if _, err := os.Stat(destPath); err == nil {
fmt.Printf("Skipping %s; already exists.\n", fileName)
continue
}

fmt.Printf("Downloading %s from %s\n", fileName, downloadURL)
resp, err := http.Get(downloadURL)
if err != nil || resp.StatusCode != 200 {
http.Error(w, fmt.Sprintf("Failed to download %s", fileName), http.StatusInternalServerError)
if resp != nil {
resp.Body.Close()
}
return
}

out, err := os.Create(destPath)
if err != nil {
http.Error(w, "Failed to create destination file", http.StatusInternalServerError)
resp.Body.Close()
return
}

bzReader := bzip2.NewReader(resp.Body)
if _, err := io.Copy(out, bzReader); err != nil {
http.Error(w, "Decompression failed", http.StatusInternalServerError)
out.Close()
resp.Body.Close()
return
}

out.Close()
resp.Body.Close()
fmt.Printf("Wrote %s\n", destPath)
}

w.Header().Set("Content-Type", "application/json")
w.WriteHeader(http.StatusOK)
w.Write([]byte(`{"message": "EVE static data is ready."}`))
}

func GetAuthURLHandler(w http.ResponseWriter, r *http.Request) {
clientID := os.Getenv("CLIENT_ID")
if clientID == "" {
http.Error(w, "CLIENT_ID not set in environment.", http.StatusInternalServerError)
return
}

queryParams := url.Values{}
queryParams.Add("response_type", "code")
queryParams.Add("redirect_uri", redirectURI)
queryParams.Add("client_id", clientID)
queryParams.Add("state", "haul-local")
queryParams.Add("scope", strings.Join(scopes, " "))

fullURL := fmt.Sprintf("%s?%s", authURL, queryParams.Encode())
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(map[string]string{"url": fullURL})
}

func CompleteAuthHandler(w http.ResponseWriter, r *http.Request) {
var request struct {
Code string `json:"code"`
}
if err := json.NewDecoder(r.Body).Decode(&request); err != nil || request.Code == "" {
http.Error(w, "Valid 'code' is required.", http.StatusBadRequest)
return
}

clientID := os.Getenv("CLIENT_ID")
secretKey := os.Getenv("SECRET_KEY")

if clientID == "" || secretKey == "" {
http.Error(w, "Missing CLIENT_ID or SECRET_KEY", http.StatusInternalServerError)
return
}

formValues := url.Values{}
formValues.Set("grant_type", "authorization_code")
formValues.Set("code", request.Code)

req, err := http.NewRequest("POST", tokenURL, strings.NewReader(formValues.Encode()))
if err != nil {
http.Error(w, "Failed to create request.", http.StatusInternalServerError)
return
}

userPass := clientID + ":" + secretKey
encodedAuth := base64.StdEncoding.EncodeToString([]byte(userPass))
req.Header.Add("Authorization", fmt.Sprintf("Basic %s", encodedAuth))
req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
req.Header.Add("Host", "login.eveonline.com")

client := &http.Client{Timeout: 30 * time.Second}
resp, err := client.Do(req)
if err != nil || resp.StatusCode >= 400 {
http.Error(w, "Failed to swap token", http.StatusBadGateway)
return
}
defer resp.Body.Close()

var authData map[string]interface{}
if err := json.NewDecoder(resp.Body).Decode(&authData); err != nil {
http.Error(w, "Failed to decode ESI response", http.StatusInternalServerError)
return
}

expiresIn := authData["expires_in"].(float64)
authData["expires_at"] = time.Now().UTC().Unix() + int64(expiresIn)

os.MkdirAll(filepath.Dir(authFilePath), os.ModePerm)
cacheData, _ := json.MarshalIndent(authData, "", "  ")
os.WriteFile(authFilePath, cacheData, 0644)

tokenStr, _ := authData["access_token"].(string)
charInfo := extractJWTSubject(tokenStr)
appendEnvValue("character_id", charInfo)

w.Header().Set("Content-Type", "application/json")
w.WriteHeader(http.StatusOK)
w.Write([]byte(`{"message": "Auth successful, cache built."}`))
}

func extractJWTSubject(token string) string {
parts := strings.Split(token, ".")
if len(parts) < 2 {
return "unknown"
}
payload, err := base64.RawURLEncoding.DecodeString(parts[1])
if err != nil {
return "unknown"
}

var claims map[string]interface{}
if err := json.Unmarshal(payload, &claims); err != nil {
return "unknown"
}

if sub, ok := claims["sub"].(string); ok {
subParts := strings.Split(sub, ":")
return subParts[len(subParts)-1]
}
return "unknown"
}

func appendEnvValue(key, value string) {
content, err := os.ReadFile(envFilePath)
if err != nil {
content = []byte{}
}

if !bytes.Contains(content, []byte(key+"=")) {
f, _ := os.OpenFile(envFilePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
defer f.Close()
f.WriteString(fmt.Sprintf("\n%s=%s\n", key, value))
}
}