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

const VALID_STATUSES = [
  "contracts_received",
  "under_revision",
  "done",
  "validated",
  "canceled",
] as const;

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

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

export const handler: Handlers<null, AuthenticatedState> = {
  // GET /mobilites/:idMob
  async GET(
    _request: Request,
    context: FreshContext<AuthenticatedState>,
  ): Promise<Response> {
    const idMob = Number(context.params.idMob);
    if (isNaN(idMob)) {
      return new Response("Paramètre idMob invalide", { status: 400 });
    }

    const row = await db
      .select()
      .from(mobilites)
      .where(eq(mobilites.id, idMob))
      .then((rows) => rows[0] ?? null);

    if (!row) return NOT_FOUND();

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

  // PUT /mobilites/:idMob (employee only)
  async PUT(
    request: Request,
    context: FreshContext<AuthenticatedState>,
  ): Promise<Response> {
    if (!isEmployee(context.state.session)) {
      return FORBIDDEN();
    }

    const idMob = Number(context.params.idMob);
    if (isNaN(idMob)) {
      return new Response("Paramètre idMob invalide", { status: 400 });
    }

    const body = await request.json();
    const { duree, ecole, pays, status, idStage } = body;

    if (
      status !== undefined &&
      !VALID_STATUSES.includes(status)
    ) {
      return new Response(
        JSON.stringify({
          error: `status invalide, valeurs: ${VALID_STATUSES.join(", ")}`,
        }),
        { status: 400, headers: { "content-type": "application/json" } },
      );
    }

    if (duree !== undefined && (!Number.isInteger(duree) || duree < 1)) {
      return new Response(
        JSON.stringify({ error: "duree doit être un entier >= 1" }),
        { status: 400, headers: { "content-type": "application/json" } },
      );
    }

    const set: Record<string, unknown> = {};
    if (duree !== undefined) set.duree = duree;
    if (ecole !== undefined) set.ecole = ecole;
    if (pays !== undefined) set.pays = pays;
    if (status !== undefined) set.status = status;
    if (idStage !== undefined) {
      set.idStage = idStage;
      if (idStage) set.status = "validated";
    }

    if (Object.keys(set).length === 0) {
      return new Response(
        JSON.stringify({ error: "Au moins un champ à modifier requis" }),
        { status: 400, headers: { "content-type": "application/json" } },
      );
    }

    const [updated] = await db
      .update(mobilites)
      .set(set)
      .where(eq(mobilites.id, idMob))
      .returning();

    if (!updated) return NOT_FOUND();

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

  // DELETE /mobilites/:idMob (employee only)
  async DELETE(
    _request: Request,
    context: FreshContext<AuthenticatedState>,
  ): Promise<Response> {
    if (!isEmployee(context.state.session)) {
      return FORBIDDEN();
    }

    const idMob = Number(context.params.idMob);
    if (isNaN(idMob)) {
      return new Response("Paramètre idMob invalide", { status: 400 });
    }

    // Delete contract file if exists
    const row = await db
      .select({ contratMob: mobilites.contratMob })
      .from(mobilites)
      .where(eq(mobilites.id, idMob))
      .then((rows) => rows[0] ?? null);

    if (row?.contratMob) {
      try {
        await Deno.remove(`uploads/contracts/${row.contratMob}`);
      } catch { /* file may not exist */ }
    }

    const [deleted] = await db
      .delete(mobilites)
      .where(eq(mobilites.id, idMob))
      .returning();

    if (!deleted) return NOT_FOUND();

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