/**
 * modes/check-runner.ts — orchestrates a single check run.
 *
 * Pipeline:
 *   init/resolve run-state → Q0 recon (shared, once) →
 *   analysis sub-agent (buildScanTask) → fix sub-agent (buildFixTask, only
 *   with --fix) → verify gate → cleanup transient artifacts.
 *
 * Every phase is recorded on the persisted run-state via `run-state.ts`, so
 * `/pygienium-status`, `/pygienium-resume`, and `/pygienium-export` reflect
 * real progress. The check-runner is check-agnostic: a `CheckDefinition`
 * supplies the task builders and gate; this module only wires the phases
 * together.
 *
 * @module pygienium/modes/check-runner
 */

import { rm } from "node:fs/promises";
import { resolve, join } from "node:path";
import type { ExtensionUIContext } from "@oh-my-pi/pi-coding-agent";
import type { CheckDefinition, CheckScope } from "../checks/registry.js";
import { runAgentTask } from "../agent-runner.js";
import { runRecon } from "../recon.js";
import {
	createPhaseStrip,
	type SendChatMessage,
	type CheckCompletionDetails,
	type PhaseLogEntry,
	type PhaseLogStatus,
	PHASE_LABELS,
} from "../phases.js";
import type { AgentSessionEvent } from "@oh-my-pi/pi-coding-agent";
import { createPipelineFooter, footerPhaseItems } from "../footer.js";
import {
	applyPhaseStatus,
	ensureRunStateIgnored,
	initRunState,
	loadRunState,
	markCheckStatus,
	markRunStatus,
	PHASE_ANALYSIS,
	PHASE_CLEANUP,
	PHASE_FIX,
	PHASE_RECON,
	PHASE_VERIFY,
	phasesForCheck,
	recordCheckOutput,
	reconcileRunStatus,
	saveRunState,
	stateDir,
	type RunState,
} from "../run-state.js";

/** Resolve a raw arg string into a check scope (target path + flags). */
export function parseCheckArgs(raw: string, cwd: string): CheckScope {
	const tokens = raw.trim().length > 0 ? raw.trim().split(/\s+/) : [];
	let fix = false;
	let target = cwd;
	const rest: string[] = [];
	for (const tok of tokens) {
		if (tok === "--fix") {
			fix = true;
		} else if (tok.startsWith("--")) {
			rest.push(tok);
		} else {
			target = tok;
		}
	}
	// Absolute-ize target against cwd.
	target = resolve(cwd, target);
	return { cwd, target, fix, rest };
}

export interface RunCheckOptions {
	/** The check definition to run. */
	check: CheckDefinition;
	/** Working directory (from `ctx.cwd`). */
	cwd: string;
	/** Parsed scope (target + flags). When omitted, derived from `rawArgs`. */
	scope?: CheckScope;
	/** Raw command args, used when `scope` is omitted. */
	rawArgs?: string;
	/** UI context (optional; null in print mode). */
	ui?: ExtensionUIContext;
	/** Whether dialog-capable UI is available. */
	hasUI?: boolean;
	/** Pre-existing run state to update (for `/pygienium-all` and resume). */
	existingState?: RunState;
	/** Optional callback to post completion messages into the chat. */
	sendChatMessage?: SendChatMessage;
	/**
	 * Render the per-check live widget (default true). Set false when an outer
	 * strip (e.g. `/pygienium-all`) already shows this check's phase, so two
	 * spinners don't fight over the widget area.
	 */
	widget?: boolean;
	/**
	 * Render the pipeline-overview footer status line (default true). Set false
	 * when an outer run (e.g. `/pygienium-all`) already owns the footer, so two
	 * overviews never compete over the same status slot.
	 */
	footer?: boolean;
	/** Optional callback that forwards raw sub-agent events to the chat
	 * stream (see `pygienium-stream` in `index.ts`). */
	onAgentEvent?: (phase: string, event: AgentSessionEvent) => void;
	/** Optional callback to emit synthetic progress lines during non-agent
	 * phases (verify, cleanup, recon) into the chat stream. */
	sendPhaseLine?: (phase: string, text: string) => void;
	/**
	 * Ensure `<cwd>/.gitignore` excludes `.pygienium/` before this run writes
	 * state/artifacts (default true). Set false with `--no-gitignore`.
	 */
	gitignore?: boolean;
}

/** Outcome of a single check run. */
export interface CheckRunOutcome {
	/** Final check status. */
	status: "complete" | "failed" | "skipped";
	/** True when this run appended `.pygienium/` to the repo's .gitignore. */
	gitignoreAppended?: boolean;
	/** Findings text from the analysis phase. */
	findings?: string;
	/** Changes text from the fix phase (when run with --fix). */
	changes?: string;
	/** Error message on failure. */
	error?: string;
	/** The updated run state. */
	state: RunState;
}

/**
 * Run a single check end-to-end, persisting progress to run-state, and post a
 * ralpi-style completion message into the chat (header + expandable phase
 * tree) when a `sendChatMessage` callback is supplied.
 *
 * Resumable: if `existingState` already has terminal-ish progress for this
 * check, the runner resumes the last in-progress phase rather than restarting.
 */
export async function runCheck(
	opts: RunCheckOptions,
): Promise<CheckRunOutcome> {
	const startMs = Date.now();
	const outcome = await runCheckImpl(opts);
	try {
		postCheckCompletion(opts, outcome, Date.now() - startMs);
	} catch {
		// Completion posting is best-effort chat UI: a renderer or send
		// failure must never reject the run after its state was persisted.
	}
	return outcome;
}

async function runCheckImpl(opts: RunCheckOptions): Promise<CheckRunOutcome> {
	// Keep pygienium's own output out of the scanned repo's git index unless
	// the caller opted out with --no-gitignore.
	const gitignoreAppended =
		opts.gitignore === false ? false : await ensureRunStateIgnored(opts.cwd);
	const outcome = await runCheckImplInner(opts);
	return { ...outcome, gitignoreAppended };
}

async function runCheckImplInner(
	opts: RunCheckOptions,
): Promise<CheckRunOutcome> {
	const { check, cwd } = opts;
	const scope = opts.scope ?? parseCheckArgs(opts.rawArgs ?? "", cwd);

	// Resolve or init the run state, recording this check on first sight.
	const state: RunState =
		opts.existingState ?? (await loadRunState(cwd)) ?? initRunState(cwd, []);
	if (!state.checks[check.name]) {
		state.checks[check.name] = {
			name: check.name,
			label: check.label,
			status: "pending",
			fix: scope.fix,
			phases: phasesForCheck(scope.fix),
		};
	}
	await saveRunState(state);

	const strip = createPhaseStrip({
		ui: opts.ui,
		hasUI: opts.hasUI ?? false,
		checkLabel: check.label,
	});

	/** Phase tag combining check label + phase label for stream lines. */
	const phaseTag = (phaseId: string): string =>
		`${check.label}: ${PHASE_LABELS[phaseId] ?? phaseId}`;

	/** Forward a raw agent event tagged with the current phase. */
	const forward = (phaseId: string) => (event: AgentSessionEvent) =>
		opts.onAgentEvent?.(phaseTag(phaseId), event);

	/** Emit a synthetic stream line for non-agent phases (verify/cleanup/recon). */
	const phaseLine = (phaseId: string, text: string): void =>
		opts.sendPhaseLine?.(phaseTag(phaseId), text);

	// Pipeline-overview footer: a static one-line view of the full phase list
	// with the cursor on the current phase and what's to come. Detail lives in
	// the chat (phase strip + completion tree); the footer is the overview.
	// Disabled (no-op) when an outer run owns the footer, e.g. /pygienium-all.
	const phaseIds = (
		state.checks[check.name]?.phases ?? phasesForCheck(scope.fix)
	).map((p) => p.id);
	const footerIdx = new Map(phaseIds.map((id, i) => [id, i] as const));
	const footer = createPipelineFooter({
		ui: opts.ui,
		hasUI: opts.hasUI ?? false,
		enabled: opts.footer ?? true,
	});
	footer.setPipeline(
		`pygienium ${check.label}`,
		footerPhaseItems(phaseIds, PHASE_LABELS),
	);
	const footerEnter = (phaseId: string): void => {
		const i = footerIdx.get(phaseId);
		if (i !== undefined) footer.setCursor(i);
	};
	const footerComplete = (phaseId: string): void => {
		const i = footerIdx.get(phaseId);
		if (i !== undefined) footer.setItem(i, "complete");
	};

	let findings = "";
	let changes = "";
	let error: string | undefined;

	try {
		// --- Phase: gate -----------------------------------------------------
		const gateResult = await Promise.resolve(check.gate(cwd));
		if (gateResult) {
			// Skip this check entirely (no agent work).
			for (const phase of state.checks[check.name]?.phases ?? []) {
				if (phase.status === "pending") phase.status = "skipped";
			}
			for (let i = 0; i < phaseIds.length; i++) footer.setItem(i, "skipped");
			markCheckStatus(state, check.name, "skipped", gateResult);
			markRunStatus(state, reconcileRunStatus(state));
			await saveRunState(state);
			strip.setPhase(PHASE_CLEANUP);
			strip.done();
			return { status: "skipped", error: gateResult, state };
		}

		// --- Phase: recon (shared, run once per run) -------------------------
		if (!state.recon.complete) {
			strip.setPhase(PHASE_RECON);
			footerEnter(PHASE_RECON);
			applyPhaseStatus(state, check.name, PHASE_RECON, "in_progress");
			await saveRunState(state);
			phaseLine(PHASE_RECON, "scanning project structure…");
			const snapshot = await runRecon(cwd);
			state.recon = {
				complete: true,
				path: join(stateDir(cwd), "recon.json"),
				finishedAt: snapshot.createdAt,
			};
			phaseLine(PHASE_RECON, "✓ recon complete");
			applyPhaseStatus(state, check.name, PHASE_RECON, "complete");
			await saveRunState(state);
			footerComplete(PHASE_RECON);
		} else {
			// Recon already done this run — mark this check's recon complete.
			applyPhaseStatus(state, check.name, PHASE_RECON, "complete");
			footerComplete(PHASE_RECON);
		}

		// --- Phase: analysis -------------------------------------------------
		strip.setPhase(PHASE_ANALYSIS);
		footerEnter(PHASE_ANALYSIS);
		applyPhaseStatus(state, check.name, PHASE_ANALYSIS, "in_progress");
		await saveRunState(state);
		const scanTask = await check.buildScanTask(cwd, scope);
		const scanResult = await runAgentTask({
			cwd: scope.target,
			agentName: check.agentName,
			task: scanTask,
			onEvent: forward(PHASE_ANALYSIS),
		});
		findings = scanResult.text;
		recordCheckOutput(state, check.name, { findings });
		if (!scanResult.ok) {
			applyPhaseStatus(
				state,
				check.name,
				PHASE_ANALYSIS,
				"failed",
				scanResult.error,
			);
			markCheckStatus(state, check.name, "failed", scanResult.error);
			markRunStatus(state, reconcileRunStatus(state));
			await saveRunState(state);
			return { status: "failed", error: scanResult.error, findings, state };
		}
		applyPhaseStatus(state, check.name, PHASE_ANALYSIS, "complete");
		await saveRunState(state);
		footerComplete(PHASE_ANALYSIS);

		// --- Phase: fix (only with --fix) -----------------------------------
		if (scope.fix) {
			strip.setPhase(PHASE_FIX);
			footerEnter(PHASE_FIX);
			applyPhaseStatus(state, check.name, PHASE_FIX, "in_progress");
			await saveRunState(state);
			const fixTask = await check.buildFixTask(cwd, scope, findings);
			const fixResult = await runAgentTask({
				cwd: scope.target,
				agentName: check.fixAgentName ?? "fixer",
				task: fixTask,
				onEvent: forward(PHASE_FIX),
			});
			changes = fixResult.text;
			recordCheckOutput(state, check.name, { changes });
			if (!fixResult.ok) {
				applyPhaseStatus(
					state,
					check.name,
					PHASE_FIX,
					"failed",
					fixResult.error,
				);
				markCheckStatus(state, check.name, "failed", fixResult.error);
				markRunStatus(state, reconcileRunStatus(state));
				await saveRunState(state);
				return {
					status: "failed",
					error: fixResult.error,
					findings,
					changes,
					state,
				};
			}
			applyPhaseStatus(state, check.name, PHASE_FIX, "complete");
			await saveRunState(state);
			footerComplete(PHASE_FIX);
		}

		// --- Phase: verify ---------------------------------------------------
		strip.setPhase(PHASE_VERIFY);
		footerEnter(PHASE_VERIFY);
		applyPhaseStatus(state, check.name, PHASE_VERIFY, "in_progress");
		await saveRunState(state);
		phaseLine(PHASE_VERIFY, "checking artifacts…");
		// Verify is a lightweight self-check. A check may supply a dedicated
		// `verify` hook to confirm its artifacts were produced (e.g.
		// findings.md / changes.md exist). When absent, fall back to re-running
		// the gate — unchanged from the historical behaviour.
		const verifyResult = await Promise.resolve(
			check.verify ? check.verify(scope) : check.gate(cwd),
		);
		if (verifyResult) {
			applyPhaseStatus(state, check.name, PHASE_VERIFY, "failed", verifyResult);
			markCheckStatus(state, check.name, "failed", verifyResult);
			markRunStatus(state, reconcileRunStatus(state));
			await saveRunState(state);
			return {
				status: "failed",
				error: verifyResult,
				findings,
				changes,
				state,
			};
		}
		phaseLine(PHASE_VERIFY, "✓ artifacts confirmed");
		applyPhaseStatus(state, check.name, PHASE_VERIFY, "complete");
		await saveRunState(state);
		footerComplete(PHASE_VERIFY);

		// --- Phase: cleanup --------------------------------------------------
		strip.setPhase(PHASE_CLEANUP);
		footerEnter(PHASE_CLEANUP);
		applyPhaseStatus(state, check.name, PHASE_CLEANUP, "in_progress");
		await saveRunState(state);
		phaseLine(PHASE_CLEANUP, "removing transient artifacts…");
		await cleanupTransientArtifacts(cwd, check.name);
		phaseLine(PHASE_CLEANUP, "✓ done");
		applyPhaseStatus(state, check.name, PHASE_CLEANUP, "complete");
		footerComplete(PHASE_CLEANUP);
		markCheckStatus(state, check.name, "complete");
		markRunStatus(state, reconcileRunStatus(state));
		await saveRunState(state);

		return { status: "complete", findings, changes, state };
	} catch (err) {
		error = err instanceof Error ? err.message : String(err);
		markCheckStatus(state, check.name, "failed", error);
		markRunStatus(state, reconcileRunStatus(state));
		try {
			await saveRunState(state);
		} catch (saveErr) {
			// A failing state save inside the error path must not mask the
			// original error or escape as an unhandled rejection (which would
			// kill the run with nothing persisted or reported).
			error += `; (also failed to persist run-state: ${
				saveErr instanceof Error ? saveErr.message : String(saveErr)
			})`;
		}
		return { status: "failed", error, findings, changes, state };
	} finally {
		strip.done();
		footer.done();
	}
}

/** Map a run-state `PhaseStatus` to a completion-log status. */
function phaseLogStatus(status: string | undefined): PhaseLogStatus {
	switch (status) {
		case "complete":
			return "complete";
		case "failed":
			return "failed";
		case "skipped":
			return "skipped";
		default:
			return "running";
	}
}

/** Glyph for a check's terminal status. */
function statusGlyph(status: CheckRunOutcome["status"]): string {
	switch (status) {
		case "complete":
			return "✓";
		case "failed":
			return "✗";
		default:
			return "-";
	}
}

/** Count non-empty lines in captured findings/changes text. */
function lineCount(text: string | undefined): number {
	if (!text) return 0;
	return text.split(/\r?\n/).filter((l) => l.trim().length > 0).length;
}

/** Format a duration in milliseconds as `1m 2s` / `5s` / `320ms`. */
function formatDuration(ms: number): string {
	const s = Math.floor(ms / 1000);
	if (s < 1) return `${ms}ms`;
	if (s < 60) return `${s}s`;
	const m = Math.floor(s / 60);
	const rem = s % 60;
	return rem ? `${m}m ${rem}s` : `${m}m`;
}

/** Build the expandable phase tree carried in the completion message. */
function buildPhaseLog(
	state: RunState,
	checkName: string,
	findings?: string,
	changes?: string,
): PhaseLogEntry[] {
	const phases = state.checks[checkName]?.phases ?? [];
	return phases.map((p) => {
		const entry: PhaseLogEntry = {
			id: p.id,
			label: PHASE_LABELS[p.id] ?? p.id,
			status: phaseLogStatus(p.status),
		};
		if (p.id === PHASE_ANALYSIS && findings) {
			entry.note = `findings: ${lineCount(findings)} lines`;
		} else if (p.id === PHASE_FIX && changes) {
			entry.note = `changes: ${lineCount(changes)} lines`;
		} else if (p.error) {
			entry.note = p.error;
		}
		return entry;
	});
}

/**
 * Post a single ralpi-style completion message (header + phase tree) into the
 * chat via `sendChatMessage`. No-op when no callback is wired (print/json
 * modes). Mirrors ralpi's per-loop completion message.
 */
function postCheckCompletion(
	opts: RunCheckOptions,
	outcome: CheckRunOutcome,
	durationMs: number,
): void {
	const send = opts.sendChatMessage;
	if (!send) return;
	const check = opts.check;
	const status = outcome.status;
	const glyph = statusGlyph(status);
	const fix = Boolean(
		(opts.scope ?? parseCheckArgs(opts.rawArgs ?? "", opts.cwd)).fix,
	);
	const fixTag = fix ? " --fix" : "";
	const header = `${glyph} pygienium ${check.label}${fixTag} · ${status} (${formatDuration(durationMs)})`;

	const details: CheckCompletionDetails = {
		checkLabel: check.label,
		status,
		fix,
		durationMs,
		phases: buildPhaseLog(
			outcome.state,
			check.name,
			outcome.findings,
			outcome.changes,
		),
		error: outcome.error,
	};

	send(header, { phase: "complete", completion: details });
}

/**
 * Remove transient per-check scratch artifacts (e.g. agent-extracted
 * manifests) written under `<cwd>/.pygienium/<check>-tmp-*`. Findings and
 * changes are kept in run-state, not these scratch files, so removing them is
 * safe.
 */
async function cleanupTransientArtifacts(
	cwd: string,
	checkName: string,
): Promise<void> {
	const dir = stateDir(cwd);
	// Best-effort: remove any `*-tmp-<check>` entries created by agents.
	const { readdir } = await import("node:fs/promises");
	let entries: string[];
	try {
		entries = await readdir(dir);
	} catch {
		return;
	}
	for (const entry of entries) {
		if (entry.includes(`-tmp-${checkName}`)) {
			await rm(join(dir, entry), { recursive: true, force: true }).catch(
				() => {},
			);
		}
	}
}