// SPDX-FileCopyrightText: 2025 Matthew Fennell <matthew@fennell.dev>
//
// SPDX-License-Identifier: AGPL-3.0-or-later

use dirs;
use fmt;
use getopt;
use io;
use net::uri;
use os::exec;
use os;
use strings;

type engine = struct {
	name: str,
	template: str,
};

type mode = enum {
	BROWSER,
	COPY,
	STDOUT,
};

export fn main() void = {
	const engines = get_engines(config_file_contents());
	const (mode, name, query) = parsed(os::args, default_engine(), names(engines));
	const template = match (get_chosen_template(name, engines)) {
		case let chosen_template: str => yield chosen_template;
		case => fmt::fatalf("No template found for {}", name);
	};
	const link = get_link(query, template);
	defer free(link);
	switch (mode) {
		case mode::BROWSER => browser(link);
		case mode::COPY => copy(link);
		case mode::STDOUT => fmt::println(link)!;
	};
};

fn names(engines: []engine) []str = {
	return {
		let names: []str = [];
		for (const engine .. engines) {
			append(names, engine.name);
		};
		yield names;
	};
};

fn parsed(args: []str, default_engine: str, names: []str) (mode, str, str) = {
	const cmd = getopt::parse(args, "search selected engine with the given query",
		('b', "open browser"),
		('c', "copy link"),
		('l', "list engines"),
		"[engine]", "query");
	defer getopt::finish(&cmd);

	let mode = mode::STDOUT;

	for (const opt .. cmd.opts) {
		switch (opt.0) {
		case 'b' => mode = mode::BROWSER;
		case 'c' => mode = mode::COPY;
		case 'l' => {
			for (let name .. names) { fmt::println(name)!; };
			os::exit(os::status::SUCCESS);
		};
		case => fmt::fatal("Unknown option given");
		};
	};

	const specified_engine: (str | void) = {
		const proposed = cmd.args[0];
		let engine: (str | void) = void;
		for (let name .. names) {
			if (proposed == name) {
				engine = proposed;
				break;
			};
		};
		yield engine;
	};

	const (engine, query) = match (specified_engine) {
		case let specified: str => yield (specified, cmd.args[1..]);
		case => yield (default_engine, cmd.args);
	};

	const query = strings::join(" ", query...);

	return (mode, engine, query);
};

fn default_engine() str = {
	return "marginalia";
};

fn config_file_contents() str = {
	const config_file = dirs::config("search");
	const config_file = strings::concat(config_file, "/engines.conf");
	const engines: io::file = os::open(config_file)!;
	const engines: []u8 = io::drain(engines)!;
	return strings::fromutf8(engines)!;
};

fn get_engines(ssv_contents: str) []engine = {
	const engines: []str = strings::split(ssv_contents, "\n");
	return {
		let result: []engine = [];
		for (let entry: str .. engines) {
			if (entry == "") {
				continue;
			};
			const slice = strings::split(entry, " ");
			assert(len(slice) == 2);
			append(result, engine { name = slice[0], template = slice[1] });
		};
		yield result;
	};
};

fn get_chosen_template(name: str, engines: []engine) (void | str) = {
	for (const engine .. engines) {
		if (engine.name == name) {
			return engine.template;
		};
	};
};

// Caller must free result
fn get_link(query: str, template: str) str = {
	const encoded = encoded(query);
	const link = strings::replace(template, "%s", encoded);
	return link;
};

fn encoded(query: str) str = {
	const encoded = net::uri::encodequery([("search", query)]);
	const encoded = strings::cut(encoded, "=").1;
	return encoded;
};

fn browser(link: str) void = {
	const cmd = os::exec::cmd("edbrowse", link);
	const cmd = match (cmd) {
		case let cmd: os::exec::command => yield cmd;
		case => fmt::fatal("Could not start browser");
	};
	os::exec::exec(&cmd);
};

fn copy(link: str) void = {
	const cmd = os::exec::cmd("wl-copy", "--primary", "--trim-newline", link);
	const cmd = match (cmd) {
		case let cmd: os::exec::command => yield cmd;
		case => fmt::fatal("Could not copy");
	};
	os::exec::exec(&cmd);
};

@test fn should_handle_single_entry() void = {
	const engines = get_engines("wikipedia https://en.wikipedia.org/wiki/%s");
	assert(len(engines) == 1);
	const engine = engines[0];
	assert(engine.name == "wikipedia");
	assert(engine.template == "https://en.wikipedia.org/wiki/%s");
};

@test fn should_handle_multiple_entries() void = {
	const engines = get_engines("wikipedia https://en.wikipedia.org/wiki/%s\nmarginalia https://old-search.marginalia.nu/search?query=%s&js=no-js");
	assert(len(engines) == 2);
	const wikipedia = engines[0];
	assert(wikipedia.name == "wikipedia");
	assert(wikipedia.template == "https://en.wikipedia.org/wiki/%s");
	const marginalia = engines[1];
	assert(marginalia.name == "marginalia");
	assert(marginalia.template == "https://old-search.marginalia.nu/search?query=%s&js=no-js");
};

@test fn should_handle_final_newline() void = {
	const engines = get_engines("wikipedia https://en.wikipedia.org/wiki/%s\n");
	assert(len(engines) == 1);
};

@test fn should_return_none_if_no_engines() void = {
	const template = get_chosen_template("wikipedia", []);
	assert(template is void);
};

@test fn should_return_none_if_engine_not_found() void = {
	const template = get_chosen_template("wikipedia", [
		engine {
			name = "marginalia",
			template = "https://old-search.marginalia.nu/search?query=%s&js=no-js",
		}
	]);
	assert(template is void);
};

@test fn should_return_query_string_if_engine_found() void = {
	const template = get_chosen_template("wikipedia", [
		engine {
			name = "wikipedia",
			template = "https://en.wikipedia.org/wiki/%s",
		}
	]);
	assert(template is str);
	assert(template as str == "https://en.wikipedia.org/wiki/%s");
};

@test fn space_should_be_encoded() void = {
	const encoded_query = encoded("hello world");
	assert(encoded_query == "hello%20world");
};

@test fn should_handle_equals_sign() void = {
	const encoded_query = encoded("does 1+1=2?");
	assert(encoded_query == "does%201+1=2?");
};

@test fn should_put_query_in_template() void = {
	const query = "Dune (2021 film)";
	const template = "https://en.wikipedia.org/wiki/%s";
	const link = get_link(query, template);
	defer free(link);
	assert(link == "https://en.wikipedia.org/wiki/Dune%20(2021%20film)");
};

@test fn should_separate_name_and_query() void = {
	const args = ["search", "marginalia", "recipe"];
	const (_, name, query) = parsed(args, "marginalia", ["marginalia"]);
	assert(name == "marginalia");
	assert(query == "recipe");
};

@test fn query_should_contain_all_remaining_args() void = {
	const args = ["search", "marginalia", "recipe", "book"];
	const (_, name, query) = parsed(args, "marginalia", ["marginalia"]);
	assert(name == "marginalia");
	assert(query == "recipe book");
};

@test fn should_use_default_engine_if_none_specified() void = {
	const args = ["search", "recipe", "book"];
	const (_, name, query) = parsed(args, "marginalia", ["marginalia", "osm"]);
	assert(name == "marginalia");
	assert(query == "recipe book");
};

@test fn should_default_to_stdout() void = {
	const (mode, _, _) = parsed(["search", "marginalia", "recipe", "book"], "marginalia", ["marginalia"]);
	assert(mode == mode::STDOUT);
};

@test fn can_request_copy() void = {
	const (mode, _, _) = parsed(["search", "-c", "marginalia", "recipe", "book"], "marginalia", ["marginalia"]);
	assert(mode == mode::COPY);
};

@test fn can_request_browser() void = {
	const (mode, _, _) = parsed(["search", "-b", "marginalia", "recipe", "book"], "marginalia", ["marginalia"]);
	assert(mode == mode::BROWSER);
};

@test fn returns_list_of_engine_names() void = {
	const names = names([
		engine {
			name = "marginalia",
			template = "https://old-search.marginalia.nu/search?query=%s&js=no-js"
		},
		engine {
			name = "wikipedia",
			template = "https://en.wikipedia.org/wiki/%s"
		},
	]);
	assert(len(names) == 2);
	assert(names[0] == "marginalia");
	assert(names[1] == "wikipedia");
};