import { serve } from "https://deno.land/std@0.190.0/http/server.ts";
import { createClient } from "https://esm.sh/@supabase/supabase-js@2";

const corsHeaders = {
  "Access-Control-Allow-Origin": "*",
  "Access-Control-Allow-Headers": "authorization, x-client-info, apikey, content-type",
};

interface GoogleServiceAccount {
  type: string;
  project_id: string;
  private_key_id: string;
  private_key: string;
  client_email: string;
  client_id: string;
  token_uri: string;
}

interface CreateMeetRequest {
  slot_id: string;
  date: string;
  start_time: string;
  end_time: string;
  client_name: string;
  client_email: string;
  topic: string;
  notes?: string;
}

// Function to create JWT and get access token using native Web Crypto API
async function getGoogleAccessToken(serviceAccount: GoogleServiceAccount): Promise<string> {
  try {
    const now = Math.floor(Date.now() / 1000);

    // Build JWT header and payload manually
    const header = {
      alg: "RS256",
      typ: "JWT",
    };

    const payload = {
      iss: serviceAccount.client_email,
      scope: "https://www.googleapis.com/auth/calendar",
      aud: serviceAccount.token_uri,
      exp: now + 3600,
      iat: now,
    };

    // Encode header and payload (base64url)
    const base64UrlEncode = (str: string) => {
      return btoa(str)
        .replace(/\+/g, "-")
        .replace(/\//g, "_")
        .replace(/=/g, "");
    };

    const encodedHeader = base64UrlEncode(JSON.stringify(header));
    const encodedPayload = base64UrlEncode(JSON.stringify(payload));
    const signatureInput = `${encodedHeader}.${encodedPayload}`;

    // Convert PEM to binary
    const keyData = serviceAccount.private_key
      .replace(/-----BEGIN PRIVATE KEY-----/g, "")
      .replace(/-----END PRIVATE KEY-----/g, "")
      .replace(/\s/g, "");

    const binaryKey = Uint8Array.from(atob(keyData), c => c.charCodeAt(0));

    // Import private key using native Web Crypto API
    const privateKey = await crypto.subtle.importKey(
      "pkcs8",
      binaryKey,
      {
        name: "RSASSA-PKCS1-v1_5",
        hash: "SHA-256",
      },
      false,
      ["sign"]
    );

    // Sign the JWT
    const signature = await crypto.subtle.sign(
      "RSASSA-PKCS1-v1_5",
      privateKey,
      new TextEncoder().encode(signatureInput)
    );

    // Encode signature
    const encodedSignature = btoa(String.fromCharCode(...new Uint8Array(signature)))
      .replace(/\+/g, "-")
      .replace(/\//g, "_")
      .replace(/=/g, "");

    const token = `${signatureInput}.${encodedSignature}`;
    console.log("Generated JWT (first 100 chars):", token.substring(0, 100));

    // Exchange JWT for access token
    const response = await fetch(serviceAccount.token_uri, {
      method: "POST",
      headers: { "Content-Type": "application/x-www-form-urlencoded" },
      body: new URLSearchParams({
        grant_type: "urn:ietf:params:oauth:grant-type:jwt-bearer",
        assertion: token,
      }),
    });

    if (!response.ok) {
      const errorText = await response.text();
      throw new Error(`Token exchange failed: ${errorText}`);
    }

    const data = await response.json();

    if (!data.access_token) {
      throw new Error("No access token in response");
    }

    return data.access_token;
  } catch (error: any) {
    console.error("Error getting Google access token:", error);
    throw error;
  }
}

serve(async (req: Request): Promise<Response> => {
  if (req.method === "OPTIONS") {
    return new Response(null, { headers: corsHeaders });
  }

  try {
    const supabaseUrl = Deno.env.get("SUPABASE_URL")!;
    const supabaseServiceKey = Deno.env.get("SUPABASE_SERVICE_ROLE_KEY")!;
    const supabase = createClient(supabaseUrl, supabaseServiceKey);

    const body: CreateMeetRequest = await req.json();
    console.log("Creating Google Meet event for slot:", body.slot_id);

    // Get platform settings
    const { data: settings, error: settingsError } = await supabase
      .from("platform_settings")
      .select("integration_google_calendar_id, google_service_account_json")
      .single();

    if (settingsError) {
      console.error("Error fetching settings:", settingsError);
      throw settingsError;
    }

    const calendarId = settings?.integration_google_calendar_id;

    if (!calendarId) {
      return new Response(
        JSON.stringify({
          success: false,
          message: "Google Calendar ID belum dikonfigurasi di Pengaturan > Integrasi"
        }),
        { status: 400, headers: { ...corsHeaders, "Content-Type": "application/json" } }
      );
    }

    // Get service account from settings
    const serviceAccountJson = settings?.google_service_account_json;

    if (!serviceAccountJson) {
      return new Response(
        JSON.stringify({
          success: false,
          message: "Google Service Account JSON belum dikonfigurasi. Tambahkan di Pengaturan > Integrasi."
        }),
        { status: 400, headers: { ...corsHeaders, "Content-Type": "application/json" } }
      );
    }

    // Parse service account JSON
    let serviceAccount: GoogleServiceAccount;
    try {
      serviceAccount = JSON.parse(serviceAccountJson);
    } catch (error: any) {
      console.error("Failed to parse service account JSON:", error);
      return new Response(
        JSON.stringify({
          success: false,
          message: "Format Google Service Account JSON tidak valid: " + error.message
        }),
        { status: 400, headers: { ...corsHeaders, "Content-Type": "application/json" } }
      );
    }

    // Get access token
    const accessToken = await getGoogleAccessToken(serviceAccount);
    console.log("Got access token");

    // Build event data
    const startDate = new Date(`${body.date}T${body.start_time}`);
    const endDate = new Date(`${body.date}T${body.end_time}`);

    const eventData = {
      summary: `Konsultasi: ${body.topic} - ${body.client_name}`,
      description: `Client: ${body.client_email}\n\nNotes: ${body.notes || '-'}\n\nSlot ID: ${body.slot_id}`,
      start: {
        dateTime: startDate.toISOString(),
        timeZone: "Asia/Jakarta",
      },
      end: {
        dateTime: endDate.toISOString(),
        timeZone: "Asia/Jakarta",
      },
      // Note: attendees removed because service accounts need Domain-Wide Delegation
      // Client email is included in description instead
      conferenceData: {
        createRequest: {
          requestId: body.slot_id,
        },
      },
    };

    console.log("Creating event in calendar:", calendarId);
    console.log("Event data:", JSON.stringify(eventData, null, 2));

    // Create event via Google Calendar API
    const calendarResponse = await fetch(
      `https://www.googleapis.com/calendar/v3/calendars/${encodeURIComponent(calendarId)}/events?conferenceDataVersion=1`,
      {
        method: "POST",
        headers: {
          "Authorization": `Bearer ${accessToken}`,
          "Content-Type": "application/json",
        },
        body: JSON.stringify(eventData),
      }
    );

    console.log("Calendar API response status:", calendarResponse.status);

    if (!calendarResponse.ok) {
      const errorText = await calendarResponse.text();
      console.error("Google Calendar API error:", errorText);
      return new Response(
        JSON.stringify({
          success: false,
          message: "Gagal membuat event di Google Calendar: " + errorText
        }),
        { status: 500, headers: { ...corsHeaders, "Content-Type": "application/json" } }
      );
    }

    const eventDataResult = await calendarResponse.json();
    console.log("Event created:", eventDataResult.id);
    console.log("Full event response:", JSON.stringify(eventDataResult, null, 2));

    // Check if conference data was created
    if (eventDataResult.conferenceData && eventDataResult.conferenceData.entryPoints) {
      const meetLink = eventDataResult.conferenceData.entryPoints.find((ep: any) => ep.entryPointType === "video")?.uri;

      if (meetLink) {
        await supabase
          .from("consulting_slots")
          .update({ meet_link: meetLink })
          .eq("id", body.slot_id);

        return new Response(
          JSON.stringify({
            success: true,
            meet_link: meetLink,
            event_id: eventDataResult.id,
            html_link: eventDataResult.htmlLink,
          }),
          { headers: { ...corsHeaders, "Content-Type": "application/json" } }
        );
      }
    }

    // Fallback to hangoutLink for backwards compatibility
    if (eventDataResult.hangoutLink) {
      await supabase
        .from("consulting_slots")
        .update({ meet_link: eventDataResult.hangoutLink })
        .eq("id", body.slot_id);

      return new Response(
        JSON.stringify({
          success: true,
          meet_link: eventDataResult.hangoutLink,
          event_id: eventDataResult.id,
          html_link: eventDataResult.htmlLink,
        }),
        { headers: { ...corsHeaders, "Content-Type": "application/json" } }
      );
    }

    return new Response(
      JSON.stringify({
        success: false,
        message: "Event berhasil dibuat tapi tidak ada meet link"
      }),
      { status: 500, headers: { ...corsHeaders, "Content-Type": "application/json" } }
    );

  } catch (error: any) {
    console.error("Error creating Google Meet event:", error);
    return new Response(
      JSON.stringify({
        success: false,
        message: error.message || "Unknown error occurred"
      }),
      { status: 500, headers: { ...corsHeaders, "Content-Type": "application/json" } }
    );
  }
});