import { NextRequest, NextResponse } from "next/server";
import { db, schema } from "@/lib/db";
import { eq, desc, and, inArray, gte } from "drizzle-orm";
import { v4 as uuidv4 } from "uuid";
import { getSession } from "@/lib/auth";
import type { CreateEntryRequest, EntryWithTags } from "@/lib/types";

// GET /api/entries - List entries with optional filters
export async function GET(request: NextRequest) {
  const user = await getSession();
  if (!user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  const { searchParams } = new URL(request.url);
  const moods = searchParams.get("moods")?.split(",").map(Number).filter(Boolean);
  const tagId = searchParams.get("tagId");
  const roughDay = searchParams.get("roughDay");
  const since = searchParams.get("since"); // YYYY-MM-DD

  try {
    // Build conditions - always filter by userId
    const conditions = [eq(schema.entries.userId, user.id)];
    if (moods && moods.length > 0) {
      conditions.push(inArray(schema.entries.mood, moods));
    }
    if (roughDay === "true") {
      conditions.push(eq(schema.entries.roughDay, 1));
    } else if (roughDay === "false") {
      conditions.push(eq(schema.entries.roughDay, 0));
    }
    if (since) {
      conditions.push(gte(schema.entries.date, since));
    }

    // Get entries
    const entries = await db
      .select()
      .from(schema.entries)
      .where(and(...conditions))
      .orderBy(desc(schema.entries.date), desc(schema.entries.createdAt));

    // Get tags for each entry
    const entriesWithTags: EntryWithTags[] = [];
    for (const entry of entries) {
      const entryTagRows = await db
        .select({ tag: schema.tags })
        .from(schema.entryTags)
        .innerJoin(schema.tags, eq(schema.entryTags.tagId, schema.tags.id))
        .where(eq(schema.entryTags.entryId, entry.id));

      const tags = entryTagRows.map((row) => row.tag);

      // Filter by tagId if specified
      if (tagId && !tags.some((t) => t.id === tagId)) {
        continue;
      }

      entriesWithTags.push({ ...entry, tags });
    }

    return NextResponse.json(entriesWithTags);
  } catch (error) {
    console.error("Failed to fetch entries:", error);
    return NextResponse.json({ error: "Failed to fetch entries" }, { status: 500 });
  }
}

// POST /api/entries - Create a new entry or update existing by id
export async function POST(request: NextRequest) {
  const user = await getSession();
  if (!user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  try {
    const body: CreateEntryRequest = await request.json();
    const { id: existingId, date, text, mood, roughDay, tagNames } = body;

    if (!date || !text) {
      return NextResponse.json({ error: "Date and text are required" }, { status: 400 });
    }

    const now = Date.now();
    let entryId: string;

    if (existingId) {
      // Update existing entry - verify ownership
      const existing = await db
        .select()
        .from(schema.entries)
        .where(
          and(
            eq(schema.entries.id, existingId),
            eq(schema.entries.userId, user.id)
          )
        )
        .limit(1);

      if (existing.length === 0) {
        return NextResponse.json({ error: "Entry not found" }, { status: 404 });
      }

      entryId = existingId;
      await db
        .update(schema.entries)
        .set({
          text,
          mood: mood ?? null,
          roughDay: roughDay ? 1 : 0,
          updatedAt: now,
        })
        .where(eq(schema.entries.id, entryId));
    } else {
      // Create new entry
      entryId = uuidv4();
      await db.insert(schema.entries).values({
        id: entryId,
        userId: user.id,
        date,
        text,
        mood: mood ?? null,
        roughDay: roughDay ? 1 : 0,
        createdAt: now,
        updatedAt: now,
      });
    }

    // Update tags
    // Remove existing tag associations
    await db.delete(schema.entryTags).where(eq(schema.entryTags.entryId, entryId));

    // Add new tags
    if (tagNames && tagNames.length > 0) {
      for (const name of tagNames) {
        const normalizedName = name.toLowerCase().trim();
        if (!normalizedName) continue;

        // Find or create tag for this user
        let tag = await db
          .select()
          .from(schema.tags)
          .where(
            and(
              eq(schema.tags.userId, user.id),
              eq(schema.tags.name, normalizedName)
            )
          )
          .limit(1);

        let tagId: string;
        if (tag.length === 0) {
          tagId = uuidv4();
          await db.insert(schema.tags).values({
            id: tagId,
            userId: user.id,
            name: normalizedName,
            createdAt: now,
          });
        } else {
          tagId = tag[0].id;
        }

        // Create association
        await db
          .insert(schema.entryTags)
          .values({ entryId, tagId })
          .onConflictDoNothing();
      }
    }

    // Fetch and return the updated entry with tags
    const entry = await db
      .select()
      .from(schema.entries)
      .where(eq(schema.entries.id, entryId))
      .limit(1);

    const entryTagRows = await db
      .select({ tag: schema.tags })
      .from(schema.entryTags)
      .innerJoin(schema.tags, eq(schema.entryTags.tagId, schema.tags.id))
      .where(eq(schema.entryTags.entryId, entryId));

    const entryWithTags: EntryWithTags = {
      ...entry[0],
      tags: entryTagRows.map((row) => row.tag),
    };

    return NextResponse.json(entryWithTags);
  } catch (error) {
    console.error("Failed to create/update entry:", error);
    return NextResponse.json({ error: "Failed to save entry" }, { status: 500 });
  }
}