import { configFromEnvironment } from "./config.js";
import { createHookDebugTimer } from "./debug-log.js";
import { fingerprintDynamicTargets } from "./dynamic-target-fingerprints.js";
import { formatAdditionalContextOutput } from "./hook-output.js";
import { displayPath, uniqueStrings } from "./path-utils.js";
import {
	clearSessionState,
	hasPostCompactPending,
	hydrateEngineState,
	isPostCompactPending,
	markSessionCompacted,
	persistEngineState,
	sessionCachePath,
} from "./persistent-cache.js";
import { withPostCompactBudget } from "./post-compact-budget.js";
import { createRulesEngine } from "./rules-engine-factory.js";
import { extractCodexToolPaths } from "./tool-paths.js";
import { filterRulesAlreadyInTranscript } from "./transcript-rule-filter.js";
import type { TranscriptSearchOptions } from "./transcript-search.js";

export type CodexSessionStartInput = {
	session_id: string;
	transcript_path: string | null;
	cwd: string;
	hook_event_name: "SessionStart";
	model: string;
	permission_mode: string;
	source: "startup" | "resume" | "clear";
};

export type CodexUserPromptSubmitInput = {
	session_id: string;
	turn_id: string;
	transcript_path: string | null;
	cwd: string;
	hook_event_name: "UserPromptSubmit";
	model: string;
	permission_mode: string;
	prompt: string;
};

export type CodexPostToolUseInput = {
	session_id: string;
	turn_id: string;
	transcript_path: string | null;
	cwd: string;
	hook_event_name: "PostToolUse";
	model: string;
	permission_mode: string;
	tool_name: string;
	tool_input: unknown;
	tool_response: unknown;
	tool_use_id: string;
};

export type CodexPostCompactInput = {
	session_id: string;
	turn_id: string;
	transcript_path: string | null;
	cwd: string;
	hook_event_name: "PostCompact";
	model: string;
	trigger: "manual" | "auto";
};

export interface CodexRulesHookOptions {
	env?: NodeJS.ProcessEnv;
	pluginDataRoot?: string;
}

export async function runSessionStartHook(
	input: CodexSessionStartInput,
	options: CodexRulesHookOptions = {},
): Promise<string> {
	const cachePath = sessionCachePath(input.session_id, options.pluginDataRoot);
	if (input.source === "clear") {
		clearSessionState(cachePath);
	} else if (input.source !== "resume" && !hasPostCompactPending(cachePath)) {
		clearSessionState(cachePath);
	}
	const postCompactPending = input.source !== "clear" && isPostCompactPending(cachePath, "static");
	const transcriptPath = input.source === "clear" ? null : input.transcript_path;
	return runStaticInjection(
		input.cwd,
		transcriptPath,
		"SessionStart",
		cachePath,
		options,
		postCompactPending ? "static" : undefined,
		{ latestCompactedReplacementOnly: postCompactPending },
	);
}

export async function runPostCompactHook(
	input: CodexPostCompactInput,
	options: CodexRulesHookOptions = {},
): Promise<string> {
	markSessionCompacted(sessionCachePath(input.session_id, options.pluginDataRoot));
	return "";
}

export async function runUserPromptSubmitHook(
	input: CodexUserPromptSubmitInput,
	options: CodexRulesHookOptions = {},
): Promise<string> {
	const cachePath = sessionCachePath(input.session_id, options.pluginDataRoot);
	const postCompactPending = isPostCompactPending(cachePath, "static");
	return runStaticInjection(
		input.cwd,
		input.transcript_path,
		"UserPromptSubmit",
		cachePath,
		options,
		postCompactPending ? "static" : undefined,
		{ latestCompactedReplacementOnly: postCompactPending },
	);
}

export async function runPostToolUseHook(
	input: CodexPostToolUseInput,
	options: CodexRulesHookOptions = {},
): Promise<string> {
	const debugTimer = createHookDebugTimer("PostToolUse");
	const config = configFromEnvironment(options.env);
	debugTimer.lap("config", { disabled: config.disabled, mode: config.mode });
	if (config.disabled || config.mode === "off" || config.mode === "static") {
		debugTimer.done({ outputBytes: 0, reason: "disabled" });
		return "";
	}

	const targetPaths = extractCodexToolPaths(input, input.cwd);
	debugTimer.lap("extract", {
		targets: targetPaths.length,
		uniqueTargets: uniqueStrings(targetPaths).length,
		tool: input.tool_name,
	});
	const firstTargetPath = targetPaths[0];
	if (firstTargetPath === undefined) {
		debugTimer.done({ outputBytes: 0, reason: "no-target" });
		return "";
	}

	const cachePath = sessionCachePath(input.session_id, options.pluginDataRoot);
	const postCompactPending = isPostCompactPending(cachePath, "dynamic");
	const engine = createRulesEngine(options, postCompactPending ? withPostCompactBudget(config) : config);
	hydrateEngineState(engine, cachePath);
	debugTimer.lap("hydrate", {
		dynamicDedupScopes: engine.state.dynamicDedup.size,
		dynamicTargetFingerprints: engine.state.dynamicTargetFingerprints.size,
		staticDedup: engine.state.staticDedup.size,
	});
	const dynamicTargetFingerprints = fingerprintDynamicTargets(input.cwd, targetPaths, config);
	debugTimer.lap("fingerprint", { fingerprints: dynamicTargetFingerprints.length });
	const pendingTargetFingerprints = dynamicTargetFingerprints.filter(
		(target) => engine.state.dynamicTargetFingerprints.get(target.cacheKey) !== target.fingerprint,
	);
	debugTimer.lap("pending", { pending: pendingTargetFingerprints.length });
	if (pendingTargetFingerprints.length === 0) {
		persistEngineState(engine, cachePath, postCompactPending ? "dynamic" : undefined);
		debugTimer.lap("persist", { reason: "no-pending" });
		debugTimer.done({ outputBytes: 0, reason: "no-pending" });
		return "";
	}

	const loaded = engine.loadDynamicRules(
		input.cwd,
		pendingTargetFingerprints.map((target) => target.targetPath),
	);
	debugTimer.lap("load", { diagnostics: loaded.diagnostics.length, loadedRules: loaded.rules.length });
	const rules = filterRulesAlreadyInTranscript(
		loaded.rules.filter((rule) => !engine.isStaticInjected(rule) && !engine.isDynamicInjected(rule)),
		input.transcript_path,
		(rule) => {
			engine.markDynamicInjected(rule);
		},
		{ latestCompactedReplacementOnly: postCompactPending },
	);
	debugTimer.lap("filter", { rules: rules.length });
	for (const target of pendingTargetFingerprints) {
		engine.state.dynamicTargetFingerprints.set(target.cacheKey, target.fingerprint);
	}
	if (rules.length === 0) {
		persistEngineState(engine, cachePath, postCompactPending ? "dynamic" : undefined);
		debugTimer.lap("persist", { reason: "no-rules" });
		debugTimer.done({ outputBytes: 0, reason: "no-rules" });
		return "";
	}

	const firstPendingTargetPath = pendingTargetFingerprints[0]?.targetPath ?? firstTargetPath;
	const block = engine.formatDynamic(rules, displayPath(input.cwd, firstPendingTargetPath));
	debugTimer.lap("format", { blockChars: block.length, rules: rules.length });
	for (const rule of rules) {
		engine.markDynamicInjected(rule);
	}
	persistEngineState(engine, cachePath, postCompactPending ? "dynamic" : undefined);
	debugTimer.lap("persist", { reason: "emit" });
	const output = formatAdditionalContextOutput("PostToolUse", block);
	debugTimer.done({ outputBytes: Buffer.byteLength(output), reason: "emit" });
	return output;
}

function runStaticInjection(
	cwd: string,
	transcriptPath: string | null,
	eventName: "SessionStart" | "UserPromptSubmit",
	cachePath: string,
	options: CodexRulesHookOptions,
	completedPostCompactChannel?: "static",
	transcriptSearchOptions: TranscriptSearchOptions = {},
): string {
	const config = configFromEnvironment(options.env);
	if (config.disabled || config.mode === "off" || config.mode === "dynamic") {
		return "";
	}

	const effectiveConfig = completedPostCompactChannel === undefined ? config : withPostCompactBudget(config);
	const engine = createRulesEngine(options, effectiveConfig);
	hydrateEngineState(engine, cachePath);
	engine.state.cwd = cwd;

	const loaded = engine.loadStaticRules(cwd);
	const rules = filterRulesAlreadyInTranscript(
		loaded.rules.filter((rule) => !engine.isStaticInjected(rule)),
		transcriptPath,
		(rule) => {
			engine.markStaticInjected(rule);
		},
		transcriptSearchOptions,
	);
	if (rules.length === 0) {
		persistEngineState(engine, cachePath, completedPostCompactChannel);
		return "";
	}

	const block = engine.formatStatic(rules);
	for (const rule of rules) {
		engine.markStaticInjected(rule);
	}
	persistEngineState(engine, cachePath, completedPostCompactChannel);
	return formatAdditionalContextOutput(eventName, block);
}