"use client";

import Link from "next/link";
import { FormEvent, useEffect, useState } from "react";
import {
  createGlobalDevice,
  createProject,
  deleteGlobalDevice,
  importProjectTransferAsNew,
  listGlobalDevices,
  updateGlobalDevice,
} from "../../frontend/utils/api";
import type {
  CreateGlobalDeviceInput,
  GlobalDeviceDto,
} from "../../frontend/types";
import { GzfPickerModal } from "../../frontend/components/gzf-picker-modal";

const PROJECTS_CHANGED_EVENT = "leistungsbilanz:projects-changed";

const emptyGlobalDevice: CreateGlobalDeviceInput = {
  name: "",
  displayName: "",
  category: "",
  quantity: 1,
  installedPowerPerUnitKw: 0.1,
  demandFactor: 1,
  phaseCount: 1,
  powerFactor: 1,
  note: "",
};

function toOptionalNumber(value: string) {
  const trimmed = value.trim();
  if (!trimmed) {
    return undefined;
  }
  return Number(trimmed);
}

export default function ProjectsPage() {
  const [globalDevices, setGlobalDevices] = useState<GlobalDeviceDto[]>([]);
  const [projectName, setProjectName] = useState("");
  const [globalDeviceForm, setGlobalDeviceForm] = useState<Record<string, string>>({
    name: "",
    displayName: "",
    category: "",
    quantity: "1",
    installedPowerPerUnitKw: "0.1",
    demandFactor: "1",
    phaseCount: "1",
    powerFactor: "1",
    note: "",
  });
  const [isSaving, setIsSaving] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [projectImport, setProjectImport] = useState<unknown>(null);
  const [projectImportFilename, setProjectImportFilename] = useState("");
  const [projectImportInputKey, setProjectImportInputKey] = useState(0);
  const [projectImportFileError, setProjectImportFileError] = useState<
    string | null
  >(null);
  const [importedProject, setImportedProject] = useState<{
    projectId: string;
    name: string;
  } | null>(null);
  const [createdProject, setCreatedProject] = useState<{
    id: string;
    name: string;
  } | null>(null);
  const [isGzfPickerOpen, setIsGzfPickerOpen] = useState(false);

  async function loadData() {
    setError(null);
    setGlobalDevices(await listGlobalDevices());
  }

  useEffect(() => {
    loadData().catch((err: unknown) =>
      setError(err instanceof Error ? err.message : "Daten konnten nicht geladen werden.")
    );
  }, []);

  async function handleCreateProject(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
    if (!projectName.trim()) {
      return;
    }
    setIsSaving(true);
    setError(null);
    setCreatedProject(null);
    try {
      const created = await createProject(projectName.trim());
      setCreatedProject({ id: created.id, name: created.name });
      setProjectName("");
      window.dispatchEvent(new Event(PROJECTS_CHANGED_EVENT));
    } catch (err) {
      setError(err instanceof Error ? err.message : "Projekt konnte nicht erstellt werden.");
    } finally {
      setIsSaving(false);
    }
  }

  async function handleProjectImportFile(file: File | undefined) {
    setProjectImport(null);
    setProjectImportFilename("");
    setProjectImportFileError(null);
    setImportedProject(null);
    if (!file) {
      return;
    }
    try {
      setProjectImport(JSON.parse(await file.text()) as unknown);
      setProjectImportFilename(file.name);
    } catch {
      setProjectImportFileError(
        "Die ausgewählte Datei enthält kein gültiges JSON."
      );
    }
  }

  async function handleImportProject() {
    if (projectImport === null) {
      return;
    }
    setIsSaving(true);
    setError(null);
    setImportedProject(null);
    try {
      const imported = await importProjectTransferAsNew(projectImport);
      setImportedProject(imported);
      setProjectImport(null);
      setProjectImportFilename("");
      setProjectImportInputKey((current) => current + 1);
      window.dispatchEvent(new Event(PROJECTS_CHANGED_EVENT));
    } catch (err) {
      setError(
        err instanceof Error
          ? err.message
          : "Projektdatei konnte nicht importiert werden."
      );
    } finally {
      setIsSaving(false);
    }
  }

  async function handleCreateGlobalDevice(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
    if (!globalDeviceForm.name.trim()) {
      return;
    }
    const payload: CreateGlobalDeviceInput = {
      name: globalDeviceForm.name.trim(),
      displayName: globalDeviceForm.displayName.trim() || globalDeviceForm.name.trim(),
      category: globalDeviceForm.category.trim() || undefined,
      quantity: Number(globalDeviceForm.quantity),
      installedPowerPerUnitKw: Number(globalDeviceForm.installedPowerPerUnitKw),
      demandFactor: Number(globalDeviceForm.demandFactor),
      phaseCount: globalDeviceForm.phaseCount === "3" ? 3 : 1,
      powerFactor: toOptionalNumber(globalDeviceForm.powerFactor),
      note: globalDeviceForm.note.trim() || undefined,
    };
    setIsSaving(true);
    setError(null);
    try {
      const created = await createGlobalDevice(payload);
      setGlobalDevices((current) => [...current, created]);
      setGlobalDeviceForm({
        name: emptyGlobalDevice.name,
        displayName: emptyGlobalDevice.displayName,
        category: emptyGlobalDevice.category ?? "",
        quantity: String(emptyGlobalDevice.quantity),
        installedPowerPerUnitKw: String(emptyGlobalDevice.installedPowerPerUnitKw),
        demandFactor: String(emptyGlobalDevice.demandFactor),
        phaseCount: String(emptyGlobalDevice.phaseCount ?? 1),
        powerFactor: String(emptyGlobalDevice.powerFactor ?? ""),
        note: emptyGlobalDevice.note ?? "",
      });
    } catch (err) {
      setError(err instanceof Error ? err.message : "Globales Gerät konnte nicht erstellt werden.");
    } finally {
      setIsSaving(false);
    }
  }

  async function handleDeleteGlobalDevice(globalDeviceId: string) {
    setIsSaving(true);
    setError(null);
    try {
      await deleteGlobalDevice(globalDeviceId);
      setGlobalDevices((current) => current.filter((item) => item.id !== globalDeviceId));
    } catch (err) {
      setError(err instanceof Error ? err.message : "Globales Gerät konnte nicht gelöscht werden.");
    } finally {
      setIsSaving(false);
    }
  }

  async function handleQuickUpdateGlobalDevice(
    device: GlobalDeviceDto,
    key: "name" | "displayName" | "category" | "phaseCount",
    value: string
  ) {
    const payload: CreateGlobalDeviceInput = {
      name: key === "name" ? value : device.name,
      displayName: key === "displayName" ? value : device.displayName,
      category: key === "category" ? value : device.category ?? undefined,
      quantity: device.quantity,
      installedPowerPerUnitKw: device.installedPowerPerUnitKw,
      demandFactor: device.demandFactor,
      phaseCount:
        key === "phaseCount"
          ? value === "3"
            ? 3
            : 1
          : device.phaseCount ?? 1,
      powerFactor: device.powerFactor ?? undefined,
      note: device.note ?? undefined,
    };
    try {
      const updated = await updateGlobalDevice(device.id, payload);
      setGlobalDevices((current) => current.map((item) => (item.id === device.id ? updated : item)));
    } catch (err) {
      setError(err instanceof Error ? err.message : "Globales Gerät konnte nicht aktualisiert werden.");
    }
  }

  return (
    <main className="container py-4">
      <div className="page-header">
        <div>
          <div className="kicker">Leistungsbilanz</div>
          <h1>Projekte</h1>
          <p className="text-secondary mb-0">Projektübersicht und globale Geräteverwaltung</p>
        </div>
      </div>

      {error ? <div className="alert alert-warning">{error}</div> : null}

      <div className="d-flex flex-column gap-4">
        <section className="card shadow-sm">
          <div className="card-header">Neues Projekt</div>
          <div className="card-body" style={{ maxWidth: 480 }}>
            <form className="vstack gap-3" onSubmit={handleCreateProject}>
              <div>
                <label className="form-label">Projektname</label>
                <input
                  className="form-control"
                  value={projectName}
                  onChange={(event) => setProjectName(event.target.value)}
                  placeholder="z. B. Neubau Schule"
                />
              </div>
              <button className="btn btn-primary" type="submit" disabled={isSaving}>
                Projekt erstellen
              </button>
            </form>
            {createdProject ? (
              <div className="alert alert-success mt-3 mb-0">
                <div className="small mb-2">
                  „{createdProject.name}“ wurde angelegt.
                </div>
                <Link
                  className="btn btn-sm btn-success"
                  href={`/projects/${createdProject.id}`}
                >
                  Projekt öffnen
                </Link>
              </div>
            ) : null}
          </div>
        </section>

        <section className="card shadow-sm">
          <div className="card-header">Projekt importieren</div>
          <div className="card-body" style={{ maxWidth: 480 }}>
            <p className="text-secondary small">
              Eine exportierte JSON-Projektdatei wird als eigenständige Kopie
              mit neuen internen IDs angelegt.
            </p>
            <label className="form-label" htmlFor="project-overview-import">
              Projektdatei auswählen
            </label>
            <input
              accept=".json,application/json"
              className="form-control"
              disabled={isSaving}
              id="project-overview-import"
              key={projectImportInputKey}
              onChange={(event) =>
                void handleProjectImportFile(event.target.files?.[0])
              }
              type="file"
            />
            {projectImportFilename ? (
              <div className="form-text">
                {projectImportFilename} ist bereit.
              </div>
            ) : null}
            {projectImportFileError ? (
              <div className="text-danger small mt-1">
                {projectImportFileError}
              </div>
            ) : null}
            <button
              className="btn btn-outline-primary mt-3 w-100"
              disabled={isSaving || projectImport === null}
              onClick={() => void handleImportProject()}
              type="button"
            >
              Als neues Projekt importieren
            </button>
            {importedProject ? (
              <div className="alert alert-success mt-3 mb-0">
                <div className="small mb-2">
                  „{importedProject.name}“ wurde angelegt.
                </div>
                <Link
                  className="btn btn-sm btn-success"
                  href={`/projects/${importedProject.projectId}`}
                >
                  Importiertes Projekt öffnen
                </Link>
              </div>
            ) : null}
          </div>
        </section>

        <section className="card shadow-sm">
          <div className="card-header">Globale Geräte / Verbraucher</div>
        <div className="card-body border-bottom">
          <form className="row g-2" onSubmit={handleCreateGlobalDevice}>
            <div className="col-12 col-md-3">
              <input
                className="form-control"
                placeholder="Interner Name"
                value={globalDeviceForm.name}
                onChange={(event) => setGlobalDeviceForm((current) => ({ ...current, name: event.target.value }))}
              />
            </div>
            <div className="col-12 col-md-3">
              <input
                className="form-control"
                placeholder="Anzeigename"
                value={globalDeviceForm.displayName}
                onChange={(event) => setGlobalDeviceForm((current) => ({ ...current, displayName: event.target.value }))}
              />
            </div>
            <div className="col-6 col-md-1">
              <input
                className="form-control"
                placeholder="Kategorie"
                value={globalDeviceForm.category}
                onChange={(event) =>
                  setGlobalDeviceForm((current) => ({ ...current, category: event.target.value }))
                }
              />
            </div>
            <div className="col-6 col-md-1">
              <input
                className="form-control"
                type="number"
                min="0"
                value={globalDeviceForm.quantity}
                onChange={(event) =>
                  setGlobalDeviceForm((current) => ({ ...current, quantity: event.target.value }))
                }
              />
            </div>
            <div className="col-6 col-md-1">
              <input
                className="form-control"
                type="number"
                step="0.01"
                min="0"
                value={globalDeviceForm.installedPowerPerUnitKw}
                onChange={(event) =>
                  setGlobalDeviceForm((current) => ({
                    ...current,
                    installedPowerPerUnitKw: event.target.value,
                  }))
                }
              />
            </div>
            <div className="col-6 col-md-2">
              <div className="input-group">
                <input
                  className="form-control"
                  type="number"
                  step="0.01"
                  min="0"
                  max="1"
                  value={globalDeviceForm.demandFactor}
                  onChange={(event) =>
                    setGlobalDeviceForm((current) => ({ ...current, demandFactor: event.target.value }))
                  }
                />
                <button
                  className="btn btn-outline-primary"
                  onClick={() => setIsGzfPickerOpen(true)}
                  title="Gleichzeitigkeitsfaktor nach AMEV wählen"
                  type="button"
                >
                  AMEV
                </button>
              </div>
            </div>
            <div className="col-6 col-md-1">
              <select
                className="form-select"
                value={globalDeviceForm.phaseCount}
                onChange={(event) =>
                  setGlobalDeviceForm((current) => ({ ...current, phaseCount: event.target.value }))
                }
              >
                <option value="1">1-phasig</option>
                <option value="3">3-phasig</option>
              </select>
            </div>
            <div className="col-6 col-md-2">
              <button className="btn btn-primary w-100" type="submit" disabled={isSaving}>
                Gerät anlegen
              </button>
            </div>
          </form>
        </div>
        <div className="table-responsive">
          <table className="table table-sm table-striped align-middle mb-0">
            <thead>
              <tr>
                <th>Interner Name</th>
                <th>Anzeigename</th>
                <th>Kategorie</th>
                <th>Anzahl</th>
                <th>Leistung je Stück [kW]</th>
                <th>GZF</th>
                <th>Phasenart</th>
                <th>Aktion</th>
              </tr>
            </thead>
            <tbody>
              {globalDevices.map((device) => (
                <tr key={device.id}>
                  <td>
                    <input
                      className="form-control form-control-sm"
                      defaultValue={device.name}
                      onBlur={(event) =>
                        event.target.value !== device.name
                          ? handleQuickUpdateGlobalDevice(device, "name", event.target.value)
                          : undefined
                      }
                    />
                  </td>
                  <td>
                    <input
                      className="form-control form-control-sm"
                      defaultValue={device.displayName}
                      onBlur={(event) =>
                        event.target.value !== device.displayName
                          ? handleQuickUpdateGlobalDevice(device, "displayName", event.target.value)
                          : undefined
                      }
                    />
                  </td>
                  <td>
                    <input
                      className="form-control form-control-sm"
                      defaultValue={device.category ?? ""}
                      onBlur={(event) =>
                        event.target.value !== (device.category ?? "")
                          ? handleQuickUpdateGlobalDevice(device, "category", event.target.value)
                          : undefined
                      }
                    />
                  </td>
                  <td>{device.quantity}</td>
                  <td>{device.installedPowerPerUnitKw}</td>
                  <td>{device.demandFactor}</td>
                  <td>
                    <select
                      className="form-select form-select-sm"
                      aria-label={`Phasenart für ${device.displayName}`}
                      value={String(device.phaseCount ?? 1)}
                      onChange={(event) =>
                        void handleQuickUpdateGlobalDevice(
                          device,
                          "phaseCount",
                          event.target.value
                        )
                      }
                    >
                      <option value="1">1-phasig</option>
                      <option value="3">3-phasig</option>
                    </select>
                  </td>
                  <td>
                    <button
                      className="btn btn-sm btn-outline-danger"
                      type="button"
                      onClick={() => handleDeleteGlobalDevice(device.id)}
                    >
                      Löschen
                    </button>
                  </td>
                </tr>
              ))}
              {!globalDevices.length ? (
                <tr>
                  <td colSpan={8} className="text-center text-secondary py-4">
                    Noch keine globalen Geräte vorhanden.
                  </td>
                </tr>
              ) : null}
            </tbody>
          </table>
        </div>
      </section>
      </div>

      {isGzfPickerOpen ? (
        <GzfPickerModal
          onClose={() => setIsGzfPickerOpen(false)}
          onSelect={(value) => {
            setGlobalDeviceForm((current) => ({ ...current, demandFactor: String(value) }));
            setIsGzfPickerOpen(false);
          }}
        />
      ) : null}
    </main>
  );
}