import { FreshContext, Handlers } from "$fresh/server.ts";
import { db } from "$root/databases/db.ts";
import { ueModules } from "$root/databases/schema.ts";
import { AuthenticatedState } from "$root/defaults/interfaces.ts";
import { and, eq } from "npm:drizzle-orm@0.45.2";

const NOT_FOUND = new Response(
  JSON.stringify({ error: "Association UE-Module introuvable" }),
  { status: 404, headers: { "content-type": "application/json" } },
);

const FORBIDDEN = new Response(null, { status: 403 });

const BAD_REQUEST = new Response(
  JSON.stringify({ error: "Paramètres invalides" }),
  { status: 400, headers: { "content-type": "application/json" } },
);

export const handler: Handlers<null, AuthenticatedState> = {
  // #39 GET /ue-modules/{idModule}/{idUE}/{idPromo}
  async GET(
    _request: Request,
    context: FreshContext<AuthenticatedState>,
  ): Promise<Response> {
    if (context.state.session.eduPersonPrimaryAffiliation !== "employee") {
      return FORBIDDEN;
    }

    const idModule = context.params.idModule;
    const idUE = Number(context.params.idUE);
    const idPromo = context.params.idPromo;

    if (isNaN(idUE)) {
      return BAD_REQUEST;
    }

    const ueModuleAssociation = await db
      .select()
      .from(ueModules)
      .where(
        eq(ueModules.idModule, idModule),
        eq(ueModules.idUE, idUE),
        eq(ueModules.idPromo, idPromo),
      )
      .then((rows) => rows[0] ?? null);

    if (!ueModuleAssociation) return NOT_FOUND;

    return new Response(JSON.stringify(ueModuleAssociation), {
      headers: { "content-type": "application/json" },
    });
  },

  // #40 PUT /ue-modules/{idModule}/{idUE}/{idPromo}
  async PUT(
    request: Request,
    context: FreshContext<AuthenticatedState>,
  ): Promise<Response> {
    if (context.state.session.eduPersonPrimaryAffiliation !== "employee") {
      return FORBIDDEN;
    }

    const idModule = context.params.idModule;
    const idUE = Number(context.params.idUE);
    const idPromo = context.params.idPromo;

    if (isNaN(idUE)) {
      return BAD_REQUEST;
    }

    const body: { coeff: number } = await request.json();

    if (typeof body.coeff !== "number") {
      return new Response(
        JSON.stringify({ error: "Le champ 'coeff' doit être un nombre" }),
        { status: 400, headers: { "content-type": "application/json" } },
      );
    }

    const [updated] = await db
      .update(ueModules)
      .set({ coeff: body.coeff })
      .where(
        and(
          eq(ueModules.idModule, idModule),
          eq(ueModules.idUE, idUE),
          eq(ueModules.idPromo, idPromo),
        ),
      )
      .returning();

    if (!updated) return NOT_FOUND;

    return new Response(
      JSON.stringify({
        idModule: updated.idModule,
        idUE: updated.idUE,
        idPromo: updated.idPromo,
        coeff: updated.coeff,
      }),
      {
        headers: { "content-type": "application/json" },
      },
    );
  },

  // #41 DELETE /ue-modules/{idModule}/{idUE}/{idPromo}
  async DELETE(
    _request: Request,
    context: FreshContext<AuthenticatedState>,
  ): Promise<Response> {
    if (context.state.session.eduPersonPrimaryAffiliation !== "employee") {
      return FORBIDDEN;
    }

    const idModule = context.params.idModule;
    const idUE = Number(context.params.idUE);
    const idPromo = context.params.idPromo;

    if (isNaN(idUE)) {
      return BAD_REQUEST;
    }

    const [deleted] = await db
      .delete(ueModules)
      .where(
        and(
          eq(ueModules.idModule, idModule),
          eq(ueModules.idUE, idUE),
          eq(ueModules.idPromo, idPromo),
        ),
      )
      .returning();

    if (!deleted) return NOT_FOUND;

    return new Response(null, { status: 204 });
  },
};