import { dirname } from "node:path";
import { isToolCallEventType, type ExtensionAPI, type ExtensionContext, type Skill } from "@earendil-works/pi-coding-agent";
import { detectSlashSkill, matchReadPathToSkillWhenEnabled, parseSkillBlocksFromText, userMessageText } from "./detect.js";
import { readSettings } from "./settings.js";
import { findRegisteredSkillByName, resolveRegisteredSkills } from "./skills-registry.js";
import { createInitialState, trackSkill, type ExtensionState } from "./state.js";

function trackReadSkillPath(
	path: string,
	ctx: ExtensionContext,
	state: ExtensionState,
	registeredSkills: Skill[],
): void {
	const settings = readSettings(ctx);
	const skills = resolveRegisteredSkills(ctx.cwd, registeredSkills);
	const matched = matchReadPathToSkillWhenEnabled(path, skills, settings.trackReadPaths);
	if (!matched) {
		return;
	}
	trackSkill(state, {
		name: matched.name,
		filePath: matched.filePath,
		baseDir: matched.baseDir,
		source: "read",
	});
}

export default function skillReinject(pi: ExtensionAPI): void {
	const state = createInitialState();
	let registeredSkills: Skill[] = [];

	pi.on("before_agent_start", async (event) => {
		registeredSkills = event.systemPromptOptions.skills ?? registeredSkills;
	});

	pi.on("input", async (event, ctx) => {
		if (event.source === "extension") {
			return { action: "continue" };
		}

		const skillName = detectSlashSkill(event.text);
		if (skillName) {
			const skills = resolveRegisteredSkills(ctx.cwd, registeredSkills);
			const skill = findRegisteredSkillByName(skills, skillName);
			if (skill) {
				trackSkill(state, {
					name: skill.name,
					filePath: skill.filePath,
					baseDir: skill.baseDir,
					source: "slash",
				});
			}
		}

		return { action: "continue" };
	});

	pi.on("message_end", async (event, ctx) => {
		if (event.message.role !== "user") {
			return;
		}

		const text = userMessageText(event.message.content);
		const skills = resolveRegisteredSkills(ctx.cwd, registeredSkills);
		for (const block of parseSkillBlocksFromText(text)) {
			const registered = findRegisteredSkillByName(skills, block.name);
			trackSkill(state, {
				name: block.name,
				filePath: registered?.filePath ?? block.location,
				baseDir: registered?.baseDir ?? dirname(block.location),
				source: "skill-block",
			});
		}
	});

	pi.on("tool_call", async (event, ctx) => {
		if (!isToolCallEventType("read", event)) {
			return;
		}
		trackReadSkillPath(event.input.path, ctx, state, registeredSkills);
	});
}