/**
 * web_search tool factory — the imperative shell that binds the pure
 * validate/format functions to the injected FirecrawlClient edge.
 *
 * Mirrors the tool-shell pattern: factory + injected dep + pure helpers +
 * a `ToolResult` returned per call. Errors surface as `{ isError: true }`
 * rather than thrown, so the model can react to the message.
 */

import type { ToolContract, ToolExecuteContext, ToolResult } from "@dispatch/kernel";
import type { FirecrawlClient } from "./client.js";
import {
	formatCrawlResults,
	formatMapResults,
	formatScrapeResult,
	formatSearchResults,
	truncateOutput,
} from "./format.js";
import type { ValidatedArgs } from "./validate.js";
import { validateArgs } from "./validate.js";

const OUTPUT_CAP = 50_000;

export interface WebSearchToolDeps {
	readonly client: FirecrawlClient;
	readonly outputCap?: number;
}

/** Dispatch validated args to the right client method and format the result. */
async function runMode(
	validated: ValidatedArgs,
	client: FirecrawlClient,
	signal: AbortSignal,
): Promise<string> {
	switch (validated.mode) {
		case "search": {
			const hits = await client.search(
				{
					query: validated.query,
					limit: validated.limit,
					...(validated.scrape
						? { scrapeOptions: { formats: ["markdown"], onlyMainContent: true } }
						: {}),
					...(validated.lang !== undefined ? { lang: validated.lang } : {}),
					...(validated.country !== undefined ? { country: validated.country } : {}),
				},
				signal,
			);
			return formatSearchResults(hits);
		}
		case "scrape": {
			const result = await client.scrape(
				{ url: validated.url, formats: [validated.format] },
				signal,
			);
			return formatScrapeResult(result);
		}
		case "crawl": {
			const pages = await client.crawl(
				{ url: validated.url, limit: validated.limit, formats: [validated.format] },
				signal,
			);
			return formatCrawlResults(pages);
		}
		case "map": {
			const links = await client.map(validated.url, signal);
			return formatMapResults(links);
		}
	}
}

/**
 * Create the `web_search` tool. `concurrencySafe: true` — web search is
 * idempotent and safe to run alongside other tools. The `network` capability
 * is declared on the extension manifest (not the tool contract).
 */
export function createWebSearchTool(deps: WebSearchToolDeps): ToolContract {
	const client = deps.client;
	const cap = deps.outputCap ?? OUTPUT_CAP;

	return {
		name: "web_search",
		description:
			"Access the web via a self-hosted Firecrawl instance. Supports search, " +
			"single-page scrape, site crawling, and sitemap discovery.",
		parameters: {
			type: "object",
			properties: {
				query: { type: "string", description: "The search query (search mode)." },
				url: { type: "string", description: "A URL to scrape, crawl, or map." },
				mode: {
					type: "string",
					enum: ["search", "scrape", "crawl", "map"],
					description:
						"Operation mode. 'search' (default when query present), 'scrape' " +
						"(default when url present), 'crawl' (recursively scrape pages from a site), " +
						"'map' (discover URLs on a site).",
				},
				limit: {
					type: "number",
					description: "Max results. Search: default 7, max 10. Crawl: default 3, max 10.",
				},
				scrape: {
					type: "boolean",
					description: "When searching, also scrape full markdown content of each result page.",
				},
				lang: {
					type: "string",
					description: 'Language code to filter search results (e.g. "en", "ja").',
				},
				country: {
					type: "string",
					description: 'Country code to filter search results (e.g. "us", "jp").',
				},
				format: {
					type: "string",
					enum: ["markdown", "text", "html"],
					description: "Format for scrape/crawl output (default: markdown).",
				},
			},
		},
		concurrencySafe: true,
		async execute(args: unknown, ctx: ToolExecuteContext): Promise<ToolResult> {
			const validated = validateArgs(args);
			if ("error" in validated) {
				return { content: validated.error, isError: true };
			}
			const span = ctx.log.span("web_search.execute", { mode: validated.mode });
			try {
				const output = await runMode(validated, client, ctx.signal);
				span.end();
				return { content: truncateOutput(output, cap) };
			} catch (err: unknown) {
				span.end({ err });
				return {
					content: `Error: ${err instanceof Error ? err.message : String(err)}`,
					isError: true,
				};
			}
		},
	};
}