// SPDX-License-Identifier: GPL-3.0-only
#include "api_http.h"

#include <ArduinoJson.h>
#include <SD.h>
#include <WebServer.h>

#include "config.h"
#include "httprange.h"  // pure, host-testable Range parser
#include "net_wifi.h"
#include "recorder.h"
#include "storage.h"

namespace {

WebServer server(80);

const char *FW_VERSION = "0.2.0";

// Format a uint64 (SD sizes exceed 32 bits) into a decimal String.
String u64(uint64_t v) {
  char b[21];
  snprintf(b, sizeof(b), "%llu", (unsigned long long)v);
  return String(b);
}

void sendJson(int code, const String &body) {
  server.sendHeader("Access-Control-Allow-Origin", "*");
  server.send(code, "application/json", body);
}

void sendError(int code, const String &msg) {
  sendJson(code, String("{\"error\":\"") + msg + "\"}");
}

// Bearer-token check for mutating endpoints. Empty stored token = auth disabled (open on a
// trusted LAN); tightening this to require a token is a security follow-up (see TODO).
bool authed() {
  String tok = config::apiToken();
  if (tok.isEmpty()) return true;
  return server.header("Authorization") == (String("Bearer ") + tok);
}

const char *recStateStr() {
  return recorder::state() == recorder::State::Recording ? "recording" : "idle";
}

// GET /api/v1/device
void handleDevice() {
  JsonDocument doc;
  doc["device_id"] = config::deviceId();
  doc["firmware_version"] = FW_VERSION;
  doc["state"] = recStateStr();
  doc["power"] = "unknown";        // battery/charge detection lands in M3
  doc["battery_pct"] = nullptr;
  doc["storage_free_bytes"] = storage::freeBytes();
  doc["storage_total_bytes"] = storage::totalBytes();
  doc["recordings_count"] = storage::countRecordings();
  doc["wifi_connected"] = net_wifi::connected();
  doc["ip"] = net_wifi::ip();
  String out;
  serializeJson(doc, out);
  sendJson(200, out);
}

// GET /api/v1/recordings
void handleList() { sendJson(200, storage::listRecordingsJson()); }

// GET /api/v1/recordings/{id}
void handleGetMeta() {
  const String id = server.pathArg(0);
  const String meta = storage::readFile(storage::recMetaPath(id));
  if (meta.isEmpty()) return sendError(404, "No such recording");
  sendJson(200, meta);
}

// DELETE /api/v1/recordings/{id}
void handleDelete() {
  if (!authed()) return sendError(401, "Unauthorized");
  const String id = server.pathArg(0);
  if (!storage::removeRecording(id)) return sendError(404, "No such recording");
  server.send(204, "application/json", "");
}

// GET /api/v1/recordings/{id}/audio  (supports HTTP Range)
void handleAudio() {
  const String id = server.pathArg(0);
  File f = SD.open(storage::recWavPath(id), FILE_READ);
  if (!f) return sendError(404, "No such recording");

  const size_t total = f.size();
  server.sendHeader("Accept-Ranges", "bytes");

  String rangeHdr = server.header("Range");
  oshttp::RangeResult rr = oshttp::parseByteRange(rangeHdr.c_str(), total);
  if (!rr.satisfiable) {
    f.close();
    return sendError(416, "Range not satisfiable");
  }
  const size_t start = rr.start;
  const size_t end = rr.end;
  const size_t len = end - start + 1;
  f.seek(start);

  if (rr.partial) {
    server.sendHeader("Content-Range",
                      "bytes " + String(start) + "-" + String(end) + "/" + String(total));
    server.setContentLength(len);
    server.send(206, "audio/wav", "");
  } else {
    server.setContentLength(total);
    server.send(200, "audio/wav", "");
  }

  uint8_t buf[1024];
  size_t remaining = len;
  while (remaining > 0) {
    size_t want = remaining < sizeof(buf) ? remaining : sizeof(buf);
    size_t n = f.read(buf, want);
    if (n == 0) break;
    server.sendContent(reinterpret_cast<char *>(buf), n);
    remaining -= n;
  }
  f.close();
}

// POST /api/v1/record/start
void handleRecordStart() {
  if (!authed()) return sendError(401, "Unauthorized");
  if (!recorder::startRecording()) return sendError(409, "Already recording");
  sendJson(200, String("{\"id\":\"") + recorder::currentId() +
                    "\",\"state\":\"recording\"}");
}

// POST /api/v1/record/stop
void handleRecordStop() {
  if (!authed()) return sendError(401, "Unauthorized");
  const String id = recorder::currentId();
  if (!recorder::stopRecording()) return sendError(409, "Not recording");
  const String meta = storage::readFile(storage::recMetaPath(id));
  sendJson(200, meta.isEmpty() ? String("{\"id\":\"") + id + "\"}" : meta);
}

// GET /api/v1/device/config  (secrets never returned)
void handleGetConfig() {
  JsonDocument doc;
  doc["device_id"] = config::deviceId();
  doc["wifi_ssid"] = config::wifiSsid();
  doc["upload_target"] = config::uploadTarget();
  doc["codec"] = "wav_pcm_s16le";
  doc["sample_rate"] = 16000;
  String out;
  serializeJson(doc, out);
  sendJson(200, out);
}

// PUT /api/v1/device/config
void handlePutConfig() {
  if (!authed()) return sendError(401, "Unauthorized");
  JsonDocument doc;
  if (deserializeJson(doc, server.arg("plain"))) {
    return sendError(400, "Invalid JSON");
  }
  if (doc["wifi_ssid"].is<const char *>()) {
    config::setWifi(doc["wifi_ssid"].as<String>(),
                    doc["wifi_psk"] | config::wifiPsk());
  }
  if (doc["api_token"].is<const char *>()) {
    config::setApiToken(doc["api_token"].as<String>());
  }
  if (doc["upload_target"].is<const char *>()) {
    config::setUploadTarget(doc["upload_target"].as<String>());
  }
  // WiFi changes take effect on next reboot/reconnect.
  sendJson(200, "{\"status\":\"ok\",\"note\":\"reboot to apply WiFi changes\"}");
}

}  // namespace

namespace api_http {

void begin() {
  // WebServer only retains headers we ask for.
  const char *headers[] = {"Authorization", "Range"};
  server.collectHeaders(headers, 2);

  server.on("/api/v1/device", HTTP_GET, handleDevice);
  server.on("/api/v1/device/config", HTTP_GET, handleGetConfig);
  server.on("/api/v1/device/config", HTTP_PUT, handlePutConfig);
  server.on("/api/v1/recordings", HTTP_GET, handleList);
  // Register the more specific /audio route before the generic {id} route.
  server.on("/api/v1/recordings/{}/audio", HTTP_GET, handleAudio);
  server.on("/api/v1/recordings/{}", HTTP_GET, handleGetMeta);
  server.on("/api/v1/recordings/{}", HTTP_DELETE, handleDelete);
  server.on("/api/v1/record/start", HTTP_POST, handleRecordStart);
  server.on("/api/v1/record/stop", HTTP_POST, handleRecordStop);

  server.onNotFound([]() { sendError(404, "Not found"); });
  server.begin();
}

void loop() { server.handleClient(); }

}  // namespace api_http