import { and, desc, eq, like } from "drizzle-orm";
import { z } from "zod";
import { evidenceMessages, evidenceThreads } from "../db/schema";
import { CHAT_PROVIDER_IDS } from "../types/timeline";
import { defineCapability } from "./context";

const SNIPPET_RADIUS = 100;

/** ~200-char excerpt of `text` centered on the first match of `query` (case-insensitive), falling back to the start of the text when there's no match to center on. */
function buildSnippet(text: string, query: string): string {
  const matchIndex = text.toLowerCase().indexOf(query.toLowerCase());
  const centerIndex = matchIndex === -1 ? 0 : matchIndex;
  const start = Math.max(0, centerIndex - SNIPPET_RADIUS);
  const end = Math.min(
    text.length,
    centerIndex + query.length + SNIPPET_RADIUS,
  );
  const prefix = start > 0 ? "…" : "";
  const suffix = end < text.length ? "…" : "";
  return `${prefix}${text.slice(start, end)}${suffix}`;
}

export const searchTranscripts = defineCapability({
  name: "searchTranscripts",
  description:
    "Full-text search across your AI conversation transcripts (all messages — user, assistant, tool). Use when the user asks what was discussed, to find a conversation about a topic, or to locate a specific transcript. Returns matching messages with a link to open the full transcript.",
  requiredScope: "timeline:read",
  inputSchema: z.object({
    query: z.string().min(1).describe("Search term to find in message text"),
    provider: z.enum(CHAT_PROVIDER_IDS).optional(),
    limit: z.number().min(1).max(50).optional().default(20),
  }),
  execute: async (ctx, { query, provider, limit }) => {
    const conditions = [like(evidenceMessages.contentText, `%${query}%`)];
    if (provider) conditions.push(eq(evidenceMessages.providerId, provider));
    // Org-scoped when running under the hub (organizationId set): never return
    // rows across tenants. Local desktop mode (organizationId null) is
    // already single-tenant, so no filter is applied there.
    if (ctx.organizationId) {
      conditions.push(eq(evidenceThreads.organizationId, ctx.organizationId));
    }

    const rows = await ctx.db
      .select({
        sessionId: evidenceThreads.externalThreadId,
        title: evidenceThreads.title,
        providerId: evidenceMessages.providerId,
        role: evidenceMessages.role,
        timestamp: evidenceMessages.timestamp,
        contentText: evidenceMessages.contentText,
      })
      .from(evidenceMessages)
      .innerJoin(
        evidenceThreads,
        eq(evidenceMessages.threadId, evidenceThreads.id),
      )
      .where(and(...conditions))
      .orderBy(desc(evidenceMessages.timestamp))
      .limit(limit || 20);

    return {
      count: rows.length,
      results: rows.map((r) => ({
        sessionId: r.sessionId,
        provider: r.providerId,
        title: r.title,
        role: r.role,
        timestamp: r.timestamp.toISOString(),
        snippet: buildSnippet(r.contentText ?? "", query),
        url: `/timeline?conversation=${r.sessionId}&provider=${r.providerId}`,
      })),
    };
  },
});