<script setup lang="ts">
import { ref, onMounted, onUnmounted, computed, nextTick, watch } from "vue";
import { useRoute, useRouter } from "vue-router";
import type { NoteType } from "@/types/note";
import { useNotesStore } from "@/stores/notes";
import { useToastStore } from "@/stores/toast";
import { renderMarkdown } from "@/utils/markdown";
import { useAssist, type NoteDraft } from "@/composables/useAssist";
import { useAutoSave } from "@/composables/useAutoSave";
import { useEditorGuards } from "@/composables/useEditorGuards";
import { useTagSuggestions } from "@/composables/useTagSuggestions";
import { useFloatingAssist } from "@/composables/useFloatingAssist";
import { apiGet, apiPost } from "@/api/client";
import type { Editor } from "@tiptap/vue-3";
import MarkdownToolbar from "@/components/MarkdownToolbar.vue";
import TiptapEditor from "@/components/TiptapEditor.vue";
import WordCount from "@/components/WordCount.vue";
import TagInput from "@/components/TagInput.vue";
import ProjectSelector from "@/components/ProjectSelector.vue";
import MilestoneSelector from "@/components/MilestoneSelector.vue";
import DiffView from "@/components/DiffView.vue";
import VersionHistorySection from "@/components/VersionHistorySection.vue";
import ConfirmDialog from "@/components/ConfirmDialog.vue";
import { Trash2 } from "lucide-vue-next";

const route = useRoute();
const router = useRouter();
const store = useNotesStore();
const toast = useToastStore();

const title = ref("");
const body = ref("");
const tags = ref<string[]>([]);
const projectId = ref<number | null>(null);
const milestoneId = ref<number | null>(null);
const noteType = ref<NoteType>("note");
const dirty = ref(false);
const saving = ref(false);
const showPreview = ref(false);
const sidebarOpen = ref(true);

const editorRef = ref<InstanceType<typeof TiptapEditor> | null>(null);
const titleRef = ref<HTMLInputElement | null>(null);
const tiptapEditor = computed<Editor | null>(() => {
  return (editorRef.value?.editor as Editor | undefined) ?? null;
});

const noteId = computed(() =>
  route.params.id ? Number(route.params.id) : null
);
const isEditing = computed(() => noteId.value !== null);

const titlePlaceholder = computed(() => {
  switch (noteType.value) {
    case 'process': return 'Process name';
    default: return 'Title';
  }
});

const renderedPreview = computed(() => renderMarkdown(body.value));

// AI Assist — pass noteId for draft persistence
const assist = useAssist(body, noteId, projectId);

// Scope selector options: "Whole document" + one per section
const scopeOptions = computed(() => {
  const opts: Array<{ value: string; label: string }> = [
    { value: '__document__', label: 'Whole document' },
  ];
  for (const section of assist.sections.value) {
    opts.push({
      value: String(assist.sections.value.indexOf(section)),
      label: section.heading || '(preamble)',
    });
  }
  return opts;
});

const scopeSelectValue = computed({
  get() {
    if (assist.scopeMode.value === 'document') return '__document__';
    if (assist.selectedSection.value) {
      const idx = assist.sections.value.indexOf(assist.selectedSection.value);
      return idx >= 0 ? String(idx) : '__document__';
    }
    return '__document__';
  },
  set(val: string) {
    if (val === '__document__') {
      assist.scopeMode.value = 'document';
      assist.selectedSection.value = null;
    } else {
      const idx = Number(val);
      const section = assist.sections.value[idx];
      if (section) {
        assist.scopeMode.value = 'section';
        assist.selectSection(section);
      }
    }
  },
});

// Floating inline assist button
const instructionRef = ref<HTMLTextAreaElement | null>(null);
const { floatingAssist, onSelectionChange, handleInlineAssist } = useFloatingAssist(
  ({ start, end }) => {
    assist.scopeMode.value = 'section';
    assist.selectTextRange(start, end);
    nextTick(() => instructionRef.value?.focus());
  }
);

function handleAssistAccept() {
  const newBody = assist.accept();
  body.value = newBody;
  markDirty();
  toast.show("Document updated");
}

// Tag suggestions
const { suggestedTags, appliedTags, suggestingTags, fetchTagSuggestions, applyTagSuggestion, dismissTagSuggestions } =
  useTagSuggestions(title, body, tags, markDirty);

// ── Link Suggestions ────────────────────────────────────────────────────────

interface LinkSuggestion {
  note_id: number;
  title: string;
  count: number;
}

const linkSuggestions = ref<LinkSuggestion[]>([]);
let linkCheckTimer: ReturnType<typeof setTimeout> | null = null;

async function fetchLinkSuggestions() {
  if (!projectId.value || !body.value || !noteId.value) {
    linkSuggestions.value = [];
    return;
  }
  try {
    const res = await apiPost<{ suggestions: LinkSuggestion[] }>('/api/notes/link-suggestions', {
      body: body.value,
      project_id: projectId.value,
      exclude_note_id: noteId.value,
    });
    linkSuggestions.value = res.suggestions;
  } catch {
    linkSuggestions.value = [];
  }
}

function scheduleLinkCheck() {
  if (linkCheckTimer) clearTimeout(linkCheckTimer);
  linkCheckTimer = setTimeout(fetchLinkSuggestions, 2000);
}

watch(body, () => {
  if (projectId.value) scheduleLinkCheck();
});

watch(noteId, () => { showPreview.value = false; });

watch(projectId, (pid) => {
  if (pid) fetchLinkSuggestions();
  else linkSuggestions.value = [];
});

/** Replace unlinked occurrences of title in body with [[title]]. */
function applyWikilink(text: string, title: string): string {
  const escaped = title.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
  const parts = text.split(/(\[\[[^\]]*\]\])/);
  const pattern = new RegExp(`\\b${escaped}\\b`, 'gi');
  return parts.map((part, i) =>
    i % 2 === 0 ? part.replace(pattern, `[[${title}]]`) : part
  ).join('');
}

function applyLink(title: string) {
  body.value = applyWikilink(body.value, title);
  markDirty();
  linkSuggestions.value = linkSuggestions.value.filter(s => s.title !== title);
}

function applyAllLinks() {
  let text = body.value;
  for (const s of linkSuggestions.value) {
    text = applyWikilink(text, s.title);
  }
  body.value = text;
  markDirty();
  linkSuggestions.value = [];
}

// Track saved state for dirty detection
let savedTitle = "";
let savedBody = "";
let savedTags: string[] = [];
let savedProjectId: number | null = null;
let savedMilestoneId: number | null = null;
let savedNoteType: NoteType = "note";

function markDirty() {
  dirty.value =
    title.value !== savedTitle ||
    body.value !== savedBody ||
    JSON.stringify(tags.value) !== JSON.stringify(savedTags) ||
    projectId.value !== savedProjectId ||
    milestoneId.value !== savedMilestoneId ||
    noteType.value !== savedNoteType;
}

function onBodyUpdate(newVal: string) {
  body.value = newVal;
  markDirty();
}

onMounted(async () => {
  if (noteId.value) {
    await store.fetchNote(noteId.value);
    if (store.currentNote) {
      title.value = store.currentNote.title;
      body.value = store.currentNote.body;
      tags.value = [...(store.currentNote.tags || [])];
      projectId.value = store.currentNote.project_id ?? null;
      milestoneId.value = store.currentNote.milestone_id ?? null;
      noteType.value = (store.currentNote.note_type as NoteType) || "note";
      savedTitle = title.value;
      savedBody = body.value;
      savedTags = [...tags.value];
      savedProjectId = projectId.value;
      savedMilestoneId = milestoneId.value;
      savedNoteType = noteType.value;
    }
  } else {
    // New note: read type from query param
    const qt = route.query.type as string | undefined;
    if (qt && ["note", "process"].includes(qt)) {
      noteType.value = qt as NoteType;
    }
  }

  // Restore pending draft if any
  try {
    const draft = await apiGet<NoteDraft>(`/api/notes/${noteId.value}/draft`);
    if (draft) assist.loadDraft(draft);
  } catch {
    // No draft — normal
  }

  await nextTick();
  titleRef.value?.focus();

  // Initial link suggestions
  fetchLinkSuggestions();
});

async function save() {
  if (saving.value) return;
  saving.value = true;
  const finalBody = body.value;
  try {
    if (isEditing.value) {
      await store.updateNote(noteId.value!, {
        title: title.value,
        body: finalBody,
        tags: tags.value,
        project_id: projectId.value,
        milestone_id: milestoneId.value,
        note_type: noteType.value,
      });
      savedTitle = title.value;
      savedBody = body.value;
      savedTags = [...tags.value];
      savedProjectId = projectId.value;
      savedMilestoneId = milestoneId.value;
      savedNoteType = noteType.value;
      dirty.value = false;
      toast.show("Note saved");
    } else {
      const note = await store.createNote({
        title: title.value,
        body: finalBody,
        tags: tags.value,
        project_id: projectId.value,
        milestone_id: milestoneId.value,
        note_type: noteType.value,
      });
      dirty.value = false;
      toast.show("Note created");
      router.push(`/notes/${note.id}`);
    }
  } catch {
    toast.show("Failed to save note", "error");
  } finally {
    saving.value = false;
  }
}

const showDeleteConfirm = ref(false);

function remove() {
  if (noteId.value) showDeleteConfirm.value = true;
}

async function confirmDelete() {
  showDeleteConfirm.value = false;
  if (!noteId.value) return;
  try {
    await store.deleteNote(noteId.value);
    dirty.value = false;
    toast.show("Note deleted");
    router.push(projectId.value ? `/projects/${projectId.value}` : "/");
  } catch {
    toast.show("Failed to delete note", "error");
  }
}

// Auto-save every 5 minutes
async function doAutoSave() {
  if (!isEditing.value || saving.value) return;
  saving.value = true;
  const finalBody = body.value;
  try {
    await store.updateNote(noteId.value!, {
      title: title.value, body: finalBody, tags: tags.value,
      project_id: projectId.value, milestone_id: milestoneId.value,
      note_type: noteType.value,
    });
    savedTitle = title.value;
    savedBody = body.value;
    savedTags = [...tags.value];
    savedProjectId = projectId.value;
    savedMilestoneId = milestoneId.value;
    savedNoteType = noteType.value;
    dirty.value = false;
    toast.show("Auto-saved");
  } catch {
    // Silent
  } finally {
    saving.value = false;
  }
}
useAutoSave(dirty, saving, doAutoSave);
useEditorGuards(dirty, save);

// Close any in-flight assist SSE stream when navigating away
onUnmounted(() => assist.clearSelection());
</script>

<template>
  <main class="editor-page note-editor-page">
    <div class="editor-header">
      <div class="toolbar">
        <router-link :to="projectId ? `/projects/${projectId}` : '/'" class="btn-back">← {{ projectId ? 'Project' : 'Knowledge' }}</router-link>
        <button class="btn-save" @click="save" :disabled="saving">
          {{ saving ? "Saving..." : "Save" }}
        </button>
        <button v-if="isEditing" class="btn-delete" @click="remove">
          <Trash2 :size="16" /> Delete
        </button>
        <WordCount :body="body" />
      </div>
      <input
        ref="titleRef"
        v-model="title"
        type="text"
        :placeholder="titlePlaceholder"
        class="title-input"
        @input="markDirty"
        @keydown.ctrl.s.prevent="save"
        @keydown.ctrl.e.prevent="tiptapEditor?.commands.focus()"
      />
    </div>

    <!-- Two-column body: main | sidebar -->
    <div class="note-body">

      <!-- ── Main column ────────────────────────────────────────── -->
      <div class="note-main" @keydown.ctrl.e.prevent="tiptapEditor?.commands.focus()">
        <!-- ── Process (prompt) editor ──────────────────────────── -->
        <template v-if="noteType === 'process'">
          <label class="ef-label">Prompt</label>
          <textarea
            class="prompt-editor"
            :value="body"
            @input="onBodyUpdate(($event.target as HTMLTextAreaElement).value)"
            placeholder="The prompt to run when this process is fired (markdown). If it needs inputs, instruct Claude to ask up front."
            spellcheck="false"
          ></textarea>
        </template>

        <!-- ── Generic note editor ──────────────────────────────── -->
        <template v-else>
          <div class="body-tabs-row">
            <div class="editor-tabs">
              <button :class="['tab', { active: !showPreview }]" @click="showPreview = false">Write</button>
              <button :class="['tab', { active: showPreview }]" @click="showPreview = true">Preview</button>
            </div>
            <MarkdownToolbar v-show="!showPreview && assist.state.value === 'idle'" :editor="tiptapEditor" />
          </div>

          <!-- Streaming preview -->
          <template v-if="assist.state.value === 'streaming'">
            <div class="stream-label">Generating...</div>
            <div class="stream-preview prose" v-html="renderMarkdown(assist.streamingText.value)" />
          </template>

          <!-- Review: full-document diff -->
          <template v-else-if="assist.state.value === 'review'">
            <DiffView :diff="assist.diff.value" class="main-diff" />
          </template>

          <!-- Normal editor -->
          <template v-else>
            <Transition name="tab-fade" mode="out-in">
              <div v-if="!showPreview" class="body-editor-wrap">
                <TiptapEditor
                  ref="editorRef"
                  :modelValue="body"
                  placeholder="Write your note in Markdown..."
                  @update:modelValue="onBodyUpdate"
                  @selectionChange="onSelectionChange"
                  @escape="titleRef?.focus()"
                />
              </div>
              <div
                v-else
                class="preview-pane prose"
                v-html="renderedPreview"
              />
            </Transition>
          </template>

          <!-- Error from assist -->
          <div v-if="assist.error.value" class="assist-error">{{ assist.error.value }}</div>
        </template>
      </div>

      <!-- ── Sidebar ──────────────────────────────────────────── -->
      <aside class="note-sidebar">
        <button class="sidebar-toggle" @click="sidebarOpen = !sidebarOpen">
          Details {{ sidebarOpen ? '▴' : '▾' }}
        </button>

        <div :class="['sidebar-content', { 'sidebar-open': sidebarOpen }]">

          <!-- Project / Milestone / Tags -->
          <div class="sb-field">
            <label class="sb-label">Project</label>
            <ProjectSelector
              v-model="projectId"
              @update:modelValue="milestoneId = null; markDirty()"
            />
          </div>
          <div v-if="projectId" class="sb-field">
            <label class="sb-label">Milestone</label>
            <MilestoneSelector
              :projectId="projectId"
              v-model="milestoneId"
              @update:modelValue="markDirty"
            />
          </div>
          <div class="sb-field">
            <label class="sb-label">Tags</label>
            <TagInput
              v-model="tags"
              :fetchTags="(q: string) => store.fetchAllTags(q)"
              @update:modelValue="markDirty"
            />
          </div>
          <div class="tag-suggest-row">
            <button class="btn-suggest-tags" @click="fetchTagSuggestions" :disabled="suggestingTags">
              {{ suggestingTags ? "Suggesting..." : "Suggest tags" }}
            </button>
            <template v-if="suggestedTags.length > 0">
              <button
                v-for="tag in suggestedTags"
                :key="tag"
                :class="['tag-pill', { applied: appliedTags.has(tag) }]"
                :disabled="appliedTags.has(tag)"
                @click="applyTagSuggestion(tag)"
              >
                #{{ tag }}
                <span v-if="appliedTags.has(tag)" class="tag-check">&#10003;</span>
              </button>
              <button class="btn-dismiss-tags" aria-label="Dismiss tag suggestions" @click="dismissTagSuggestions">&times;</button>
            </template>
          </div>

          <!-- Note type -->
          <div class="sb-field">
            <label class="sb-label">Type</label>
            <select v-model="noteType" class="sb-select" @change="markDirty">
              <option value="note">Note</option>
              <option value="process">Process</option>
            </select>
          </div>

          <!-- Link Suggestions -->
          <div v-if="linkSuggestions.length > 0" class="sb-field link-suggest-field">
            <div class="sb-label-row">
              <span class="sb-label">Link Suggestions</span>
              <button class="btn-link-all" @click="applyAllLinks">Link all</button>
            </div>
            <div class="link-suggest-list">
              <div v-for="s in linkSuggestions" :key="s.note_id" class="link-suggest-item">
                <span class="link-suggest-title">[[{{ s.title }}]]</span>
                <span class="link-suggest-count">×{{ s.count }}</span>
                <button class="btn-apply-link" @click="applyLink(s.title)">Link</button>
              </div>
            </div>
          </div>

          <div class="sb-divider"></div>

          <!-- Writing Assistant (always visible) -->
          <div class="assist-section">
            <div class="assist-section-title">✨ Writing Assistant</div>

            <!-- Scope selector -->
            <div class="sb-field">
              <label class="sb-label">Scope</label>
              <select v-model="scopeSelectValue" class="sb-select" :disabled="assist.state.value === 'streaming'">
                <option
                  v-for="opt in scopeOptions"
                  :key="opt.value"
                  :value="opt.value"
                >{{ opt.label }}</option>
              </select>
            </div>

            <!-- Idle: instruction + buttons -->
            <template v-if="assist.state.value === 'idle'">
              <textarea
                ref="instructionRef"
                v-model="assist.instruction.value"
                placeholder="What should I do?"
                class="assist-instruction"
                rows="3"
                @keydown.enter.exact.prevent="assist.canSubmit.value && assist.submit()"
              ></textarea>
              <div class="assist-input-actions">
                <button
                  class="btn-generate"
                  @click="assist.submit()"
                  :disabled="!assist.canSubmit.value"
                >Generate</button>
                <button
                  class="btn-proofread"
                  @click="assist.proofread()"
                >Proofread</button>
              </div>
            </template>

            <!-- Streaming: cancel -->
            <template v-else-if="assist.state.value === 'streaming'">
              <div class="assist-active-hint">Generating… see main area</div>
              <button class="btn-clear" @click="assist.clearSelection()">Cancel</button>
            </template>

            <!-- Review: accept / reject -->
            <template v-else-if="assist.state.value === 'review'">
              <div class="assist-active-hint">Review the diff in the main area</div>
              <div class="assist-actions">
                <button class="btn-accept" @click="handleAssistAccept">Accept</button>
                <button class="btn-reject" @click="assist.reject()">Reject</button>
              </div>
            </template>
          </div>

          <VersionHistorySection
            v-if="noteId"
            :note-id="noteId"
            :current-body="body"
            @restore="(b, t) => { body = b; tags = t; markDirty(); }"
          />

        </div><!-- /sidebar-content -->
      </aside>
    </div><!-- /note-body -->

    <!-- Floating inline assist button -->
    <teleport to="body">
      <button
        v-if="floatingAssist.show"
        class="inline-assist-btn"
        :style="{ top: floatingAssist.top + 'px', left: floatingAssist.left + 'px' }"
        @mousedown.prevent="handleInlineAssist"
      >✨ Assist</button>
    </teleport>

    <!-- Delete confirmation -->
    <ConfirmDialog
      v-if="showDeleteConfirm"
      title="Delete Note"
      message="Are you sure you want to delete this note? This cannot be undone."
      @confirm="confirmDelete"
      @cancel="showDeleteConfirm = false"
    />
  </main>
</template>

<style src="@/assets/editor-shared.css" />
<style scoped>
/* ── Two-column note layout ──────────────────────────────────── */
.note-editor-page {
  max-width: 1600px;
}

.note-body {
  flex: 1;
  min-height: 0;
  display: flex;
  overflow: hidden;
  position: relative;
}

/* Main column */
.note-main {
  flex: 1;
  min-width: 0;
  overflow-y: auto;
  padding: 0.75rem 1.25rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.editor-tabs {
  display: inline-flex;
  background: var(--fs-surface-page);
  border: 1px solid var(--fs-border-color);
  border-radius: 8px;
  padding: 2px;
  gap: 2px;
  flex-shrink: 0;
}

.tab {
  background: none;
  border: none;
  border-radius: 6px;
  padding: 0.22rem 0.75rem;
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--fs-text-tertiary);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}
.tab:hover { color: var(--fs-text-primary); }
.tab.active {
  background: var(--fs-surface-hover);
  color: var(--fs-text-primary);
  box-shadow: 0 1px 3px rgba(0,0,0,0.12);
}

.tab-fade-enter-active,
.tab-fade-leave-active {
  transition: opacity 0.12s ease;
}
.tab-fade-enter-from,
.tab-fade-leave-to {
  opacity: 0;
}

.stream-label {
  font-size: 0.8rem;
  color: var(--fs-text-tertiary);
}

/* Right sidebar */
.note-sidebar {
  width: 280px;
  flex-shrink: 0;
  border-left: 1px solid var(--fs-border-color);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.sb-select, .sb-input {
  width: 100%;
  padding: 5px 8px;
  border-radius: var(--fs-radius-sm);
  border: 1px solid var(--fs-border-color);
  background: var(--fs-surface-hover);
  color: var(--fs-text-primary);
  font-size: 0.82rem;
  font-family: inherit;
  outline: none;
  transition: border-color 0.15s;
}
.sb-select:focus, .sb-input:focus {
  border-color: var(--fs-accent);
}

/* Link Suggestions */
.link-suggest-field { gap: 0.4rem; }

.sb-label-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.btn-link-all {
  font-size: 0.72rem;
  padding: 0.15rem 0.5rem;
  background: none;
  border: 1px solid var(--fs-accent);
  border-radius: var(--fs-radius-sm);
  color: var(--fs-accent);
  cursor: pointer;
  font-family: inherit;
}
.btn-link-all:hover { background: var(--fs-action-primary); color: var(--fs-text-on-action); }

.link-suggest-list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.link-suggest-item {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.78rem;
}

.link-suggest-title {
  flex: 1;
  font-family: monospace;
  color: var(--fs-accent);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.link-suggest-count {
  color: var(--fs-text-tertiary);
  font-size: 0.72rem;
  flex-shrink: 0;
}

.btn-apply-link {
  flex-shrink: 0;
  font-size: 0.72rem;
  padding: 0.1rem 0.4rem;
  background: none;
  border: 1px solid var(--fs-border-color);
  border-radius: var(--fs-radius-sm);
  cursor: pointer;
  font-family: inherit;
  color: var(--fs-text-secondary);
}
.btn-apply-link:hover { border-color: var(--fs-accent); color: var(--fs-accent); }

/* Writing Assistant section */
.assist-section {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

/* ── Process editor ─────────────────────────────────────── */
.ef-label {
  font-family: 'Fraunces', Georgia, serif;
  font-size: 0.92rem;
  color: var(--fs-accent);
}
.prompt-editor {
  width: 100%;
  min-height: 60vh;
  margin-top: 8px;
  padding: 14px 16px;
  border: 1px solid var(--fs-border-color);
  border-radius: 8px;
  background: var(--fs-surface-hover);
  color: var(--fs-text-primary);
  /* Prompts are plain markdown — a code-style editor, not rich text. */
  font-family: var(--fs-font-mono);
  font-size: 0.88rem;
  line-height: 1.55;
  tab-size: 2;
  resize: vertical;
  outline: none;
}
.prompt-editor:focus {
  border-color: var(--fs-accent);
}
/* Narrow screen: sidebar collapses */
@media (max-width: 720px) {
  .note-body { flex-direction: column; overflow-y: auto; overflow-x: hidden; }
  .note-main { padding: 0.75rem 1rem 1rem; overflow-y: visible; }
  .note-sidebar {
    width: 100%;
    border-left: none;
    border-top: 1px solid var(--fs-border-color);
    overflow-y: visible;
  }
}
</style>
