import type { ExtensionContext } from "@earendil-works/pi-coding-agent";
import { DEFAULT_PREVIEW_WIDTH, type PreviewResult } from "./menu.ts";
import { ActivityMeter, METER_UPPER_BOUND_TPS_MAX, METER_UPPER_BOUND_TPS_MIN, rateToLevel } from "./activity-meter.ts";
import { DEFAULT_WORKING_WORD, dimAttribute, ELAPSED_INTERVAL_MS, formatTokenRate, getThinkingLevelColorizer, METER_INTERVAL_MS, SHIMMER_INTERVAL_MS, SPINNER_FRAME_MS } from "./format.ts";
import { buildLoaderMessage } from "./loader-message.ts";
import { getResponseModelColorizer } from "./nvidia-green.ts";
import { isOutputStyleId, OUTPUT_STYLES } from "./output-style.ts";
import { buildCompletionMarkerContent, buildCompletionMarkerLine, buildPromptBoxLines } from "./prompt-decorator.ts";
import { formatServiceTierSummary } from "./service-tier.ts";
import { DEFAULT_SETTINGS, fromCycleDirection, fromCycleMeterUpperBound, fromCycleSpeed, isBorderStyle, isDoneMarkerBorderColor, isDoneMarkerBorderStyle, isDoneMarkerStyle, isPromptBorderColor, isSpinnerColor, isThinkingLevelColor, LOADER_ORDER_ID, MENU_ENTRIES, OUTPUT_STYLE_ID, parseLoaderOrder } from "./settings.ts";
import { isWordPackEnabled, selectWorkingTextSelection, WORD_PACK_MENU_PREFIX, wordPacksPath, type WordPack } from "./word-packs.ts";
// Simulated load for the menu preview: a 2.4s cosine wave peaking at 46 tps for the meter,
// flat 28 tps for the token readouts.
const METER_PERIOD_MS = 2400, METER_PEAK_RATE = 46, TOKEN_RATE_PER_SEC = 28;
const PROMPT_IDS = new Set(MENU_ENTRIES.filter(entry => entry.section === "User Prompt").map(entry => entry.id));
const MARKER_IDS = new Set(MENU_ENTRIES.filter(entry => entry.section === "Completion Marker").map(entry => entry.id));
function meterRate(elapsedMs: number): number { return ((1 - Math.cos((2 * Math.PI * elapsedMs) / METER_PERIOD_MS)) / 2) * METER_PEAK_RATE; }

/** Stateful, per-menu preview renderer that follows the active settings section. */
export class PreviewRenderer {
	// Preserve constructor-time randomness so rendering never changes the preview phrase.
	readonly #poolFraction = Math.random();
	readonly #packs: readonly WordPack[];
	readonly #meter = new ActivityMeter();
	#lastMeterUpdate = 0;
	#cachedPackWord = "";
	#cachedPackSignature = "";
	readonly #ctx: ExtensionContext;
	constructor(ctx: ExtensionContext, packs: readonly WordPack[] = []) {
		this.#ctx = ctx;
		this.#packs = packs;
	}
	render(values: Record<string, boolean | string>, elapsedMs: number, activeItemId?: string, width: number = DEFAULT_PREVIEW_WIDTH): PreviewResult {
		if (PROMPT_IDS.has(activeItemId ?? "")) return this.promptPreview(values, width);
		if (MARKER_IDS.has(activeItemId ?? "")) return this.markerPreview(values, width);
		if (activeItemId === "useNerdFont") return { lines: ["", `Icon preview: ${values.useNerdFont ? "" : "π"}`, ""] };
		if (activeItemId === OUTPUT_STYLE_ID) {
			const id = isOutputStyleId(values[OUTPUT_STYLE_ID]) ? values[OUTPUT_STYLE_ID] : DEFAULT_SETTINGS.outputStyle;
			return { lines: ["", OUTPUT_STYLES[id].description, this.#ctx.ui.theme.fg("dim", "Applies from your next message")] };
		}
		if (activeItemId === "showResponseModelFooter") {
			if (values.showResponseModelFooter !== true) return { lines: ["", "Response model footer is disabled.", ""] };
			const color = isThinkingLevelColor(values.responseModelColor) ? values.responseModelColor : DEFAULT_SETTINGS.decorations.responseModelColor;
			const colored = getResponseModelColorizer(this.#ctx.ui.theme, color, this.#ctx.thinkingLevel, this.#ctx.model?.provider)("test-model");
			return { lines: ["", values.responseModelDimmed === true ? dimAttribute(colored) : colored, ""] };
		}
		if (activeItemId?.startsWith(WORD_PACK_MENU_PREFIX)) return this.packPreview(activeItemId.slice(WORD_PACK_MENU_PREFIX.length), values);
		let nextRefreshInMs: number | undefined;
		if (values.shimmer !== false) {
			nextRefreshInMs = SHIMMER_INTERVAL_MS;
		} else if (values.animatedSpinner !== false) {
			nextRefreshInMs = SPINNER_FRAME_MS;
		} else if (values.tokenActivityMonitor !== false) {
			nextRefreshInMs = METER_INTERVAL_MS;
		} else if (values.elapsedTime !== false || values.outputTokens !== false) {
			nextRefreshInMs = ELAPSED_INTERVAL_MS;
		}
		const help = activeItemId === "meterUpperBoundTps"
			? this.#ctx.ui.theme.fg("dim", `⣿ at ${fromCycleMeterUpperBound(values.meterUpperBoundTps)} tps or more · ←→ presets · ␣ type ${METER_UPPER_BOUND_TPS_MIN}–${METER_UPPER_BOUND_TPS_MAX}`)
			: "";
		return { lines: ["", this.loaderPreview(values, elapsedMs), help], nextRefreshInMs };
	}
	private loaderPreview(values: Record<string, boolean | string>, elapsedMs: number): string {
		this.#meter.setDirection(fromCycleDirection(values.meterDirection));
		if (elapsedMs - this.#lastMeterUpdate >= METER_INTERVAL_MS) {
			this.#meter.push(rateToLevel(meterRate(elapsedMs), fromCycleMeterUpperBound(values.meterUpperBoundTps)));
			this.#lastMeterUpdate = elapsedMs;
		}
		const features = { substituteDefaultMessage: values.substituteDefaultMessage !== false, elapsedTime: values.elapsedTime !== false, outputTokens: values.outputTokens !== false, tokenRate: values.showTokenRate !== false, responseModel: values.showResponseModel !== false };
		const decorations = {
			shimmer: values.shimmer !== false,
			shimmerInverted: values.shimmerInverted === true,
			shimmerDirection: fromCycleDirection(values.shimmerDirection),
			shimmerSpeed: fromCycleSpeed(values.shimmerSpeed),
			tokenActivityMonitor: values.tokenActivityMonitor !== false,
			meterColor: isThinkingLevelColor(values.meterColor) ? values.meterColor : DEFAULT_SETTINGS.decorations.meterColor,
			meterDimmed: values.meterDimmed === true,
			tokenRateColor: isThinkingLevelColor(values.tokenRateColor) ? values.tokenRateColor : DEFAULT_SETTINGS.decorations.tokenRateColor,
			tokenRateDimmed: values.tokenRateDimmed === true,
			responseModelColor: isThinkingLevelColor(values.responseModelColor) ? values.responseModelColor : DEFAULT_SETTINGS.decorations.responseModelColor,
			responseModelDimmed: values.responseModelDimmed === true,
			spinnerColor: isSpinnerColor(values.spinnerColor) ? values.spinnerColor : DEFAULT_SETTINGS.decorations.spinnerColor,
		};
		let word = DEFAULT_WORKING_WORD;
		if (features.substituteDefaultMessage) {
			const packValues = this.packValues(values);
			const includeDefaultWorkingText = values.includeDefaultWorkingText !== false;
			const signature = JSON.stringify([packValues, includeDefaultWorkingText]);
			if (signature !== this.#cachedPackSignature) {
				this.#cachedPackWord = selectWorkingTextSelection(packValues, this.#packs, this.#poolFraction, includeDefaultWorkingText).text;
				this.#cachedPackSignature = signature;
			}
			word = this.#cachedPackWord;
		}
		const theme = this.#ctx.ui.theme;
		return buildLoaderMessage(theme, this.#ctx.thinkingLevel, this.#ctx.model?.provider, features, decorations, parseLoaderOrder(values[LOADER_ORDER_ID]), {
			spinnerAtMs: values.animatedSpinner !== false ? elapsedMs : undefined,
			word,
			shimmerAtMs: elapsedMs,
			renderMeter: (colorizer, dimmed) => this.#meter.render((level, char) => ActivityMeter.colorizeCell(level, char, theme, colorizer, dimmed)),
			elapsedMs,
			outputTokens: Math.max(0, Math.floor(elapsedMs / 1000 * TOKEN_RATE_PER_SEC)),
			tokenRateText: formatTokenRate(TOKEN_RATE_PER_SEC),
			responseModel: features.responseModel ? "test-model" : undefined,
		});
	}
	private packValues(values: Record<string, boolean | string>): Record<string, boolean> {
		const enabled: Record<string, boolean> = {};
		for (const pack of this.#packs) {
			const value = values[`${WORD_PACK_MENU_PREFIX}${pack.id}`];
			if (typeof value === "boolean") enabled[pack.id] = value;
		}
		return enabled;
	}
	private packPreview(id: string, values: Record<string, boolean | string>): PreviewResult {
		const pack = this.#packs.find((candidate) => candidate.id === id);
		if (!pack) return { lines: ["This word pack is unavailable."] };
		const enabled = isWordPackEnabled(id, this.packValues(values));
		const source = pack.bundled ? "Shipped example" : `Custom: ${wordPacksPath()}`;
		return { lines: [`${pack.name}: ${enabled ? "enabled" : "disabled"}`, `${pack.words.length} phrases · ${source}`, ...(pack.description ? [pack.description] : [])] };
	}
	private promptPreview(values: Record<string, boolean | string>, width: number): PreviewResult {
		if (values.decorateUserPrompt !== true) return { lines: ["User prompt decoration is disabled."] };

		const borderColor = values.borderColor;
		const borderStyle = values.borderStyle;
		const timestamp = values.promptTimestamp === true ? Date.now() : undefined;
		const lines = buildPromptBoxLines("ping", timestamp, width, this.#ctx.ui.theme, {
			showIcon: values.promptIcon === true,
			showTimestamp: values.promptTimestamp === true,
			showProvider: values.promptProvider === true,
			showModel: values.promptModel === true,
			icon: values.useNerdFont ? "" : "π",
			provider: this.#ctx.model?.provider,
			model: this.#ctx.model?.id,
			borderColor: isPromptBorderColor(borderColor) ? borderColor : DEFAULT_SETTINGS.decorations.borderColor,
			borderStyle: isBorderStyle(borderStyle) ? borderStyle : "double",
			thinkingLevel: this.#ctx.thinkingLevel,
		});
		return timestamp === undefined
			? { lines }
			: { lines, nextRefreshInMs: 1_000 - (timestamp % 1_000) };
	}
	private markerPreview(values: Record<string, boolean | string>, width: number): PreviewResult {
		if (values.doneMarker !== true) return { lines: ["Completion marker is disabled."] };
		const theme = this.#ctx.ui.theme;
		const icon = values.doneMarkerIcon === true ? theme.fg("text", values.useNerdFont === true ? "" : "π") : "";
		const word = values.randomizeDoneMarker === true ? "Concocted" : "Worked";
		const details: string[] = [];
		if (values.doneMarkerTokens === true) details.push("↓ 949 tokens");
		if (values.doneMarkerInputs === true) details.push("2 mid-turn inputs");
		if (values.doneMarkerServiceTier === true) details.push(formatServiceTierSummary([{ tier: "flex", calls: 3 }]));
		let model = "";
		if (values.doneMarkerModel === true) {
			const color = isThinkingLevelColor(values.doneMarkerModelColor) ? values.doneMarkerModelColor : DEFAULT_SETTINGS.decorations.doneMarkerModelColor;
			const modelColored = getThinkingLevelColorizer(theme, color, this.#ctx.thinkingLevel)("test-model");
			model = values.doneMarkerModelDimmed === true ? dimAttribute(modelColored) : modelColored;
		}
		const content = buildCompletionMarkerContent(theme, icon, word, "2m 52s", details, model);
		const borderStyle = isDoneMarkerBorderStyle(values.doneMarkerBorderStyle) ? values.doneMarkerBorderStyle : "none";
		const borderColor = isDoneMarkerBorderColor(values.doneMarkerBorderColor) ? values.doneMarkerBorderColor : DEFAULT_SETTINGS.decorations.doneMarkerBorderColor;
		const markerStyle = isDoneMarkerStyle(values.doneMarkerStyle) ? values.doneMarkerStyle : DEFAULT_SETTINGS.decorations.doneMarkerStyle;
		const marker = buildCompletionMarkerLine(content, width, theme, borderStyle, borderColor, markerStyle, this.#ctx.thinkingLevel);
		return { lines: ["", marker, ""] };
	}
}