/**
 * KHAELOR
 * File: src/tui/components/status-bar.ts
 * Description: The bottom status bar — real segments only, width-responsive degradation (TUI_DESIGN §11).
 *
 * Author: Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 */

import { truncateAnsi } from "../renderer/ansi.js";
import type { Theme } from "../theme.js";

export interface StatusBarData {
  /** Git branch (repo watcher). Absent when not in a repo. */
  branch?: string;
  /** Dirty counts as `+added −removed` (absent when clean or unknown). */
  dirty?: { added: number; removed: number };
  /** Configured model id. */
  model?: string;
  /** Short alias for narrow widths (falls back to a heuristic shortening). */
  modelAlias?: string;
  /** Real context utilization percent (usage vs usable window). */
  contextPct?: number;
  /** Real session cost from API usage metadata — absent when unpriceable. */
  costUsd?: number;
  /** Running background processes. */
  processCount?: number;
  /** Queued steering messages. */
  queuedCount?: number;
  /** Phase-gate ribbon (v2 §1): absent when gates are off. */
  phase?: "understand" | "design" | "implement";
}

const PHASE_GLYPH: Record<NonNullable<StatusBarData["phase"]>, string> = {
  understand: "◐",
  design: "◑",
  implement: "●",
};

const PHASE_ORDER: NonNullable<StatusBarData["phase"]>[] = ["understand", "design", "implement"];

/**
 * Phase ribbon: the active phase in ember (accent), passed phases dimmed with
 * a ✓, future phases dim — `◐ understand ─ design ─ implement` (TUI v2 §3).
 */
export function renderPhaseRibbon(
  phase: NonNullable<StatusBarData["phase"]>,
  theme: Theme,
  compact: boolean,
): string {
  if (compact) {
    return theme.paint("accent", `${PHASE_GLYPH[phase]} ${phase.toUpperCase()}`);
  }
  const activeIndex = PHASE_ORDER.indexOf(phase);
  const parts = PHASE_ORDER.map((name, index) => {
    if (index === activeIndex) return theme.paint("accent", `${PHASE_GLYPH[name]} ${name.toUpperCase()}`);
    if (index < activeIndex) return theme.paint("dim", `✓ ${name}`);
    return theme.paint("dim", name);
  });
  return parts.join(theme.paint("dim", " ─ "));
}

/** Context gauge `▰▰▰▱▱▱▱▱ 62%` — teal < 50, warning < 80, error above; ≥ 80 nudges /compact (TUI v2 §3). */
export function renderContextGauge(pct: number, theme: Theme): string {
  const clamped = Math.max(0, Math.min(100, Math.round(pct)));
  const filled = Math.round((clamped / 100) * 8);
  const bar = "▰".repeat(filled) + "▱".repeat(8 - filled);
  const role = clamped >= 80 ? "error" : clamped >= 50 ? "warning" : "teal";
  const nudge = clamped >= 80 ? " · /compact" : "";
  return theme.paint(role, `${bar} ${clamped}%${nudge}`);
}

function shortModel(data: StatusBarData): string | undefined {
  if (data.modelAlias !== undefined) return data.modelAlias;
  if (data.model === undefined) return undefined;
  // "claude-sonnet-4-5" → "sonnet"; unknown shapes keep their id.
  const m = /^claude-([a-z]+)/.exec(data.model);
  return m ? (m[1] as string) : data.model;
}

function contextSegment(data: StatusBarData, theme: Theme, withWord: boolean): string | undefined {
  if (data.contextPct === undefined) return undefined;
  const pct = Math.round(data.contextPct);
  let text = withWord ? `context ${pct}%` : `${pct}%`;
  if (pct >= 80) text += " · /compact";
  if (pct >= 90) return theme.paint("error", text);
  if (pct >= 80) return theme.paint("warning", text);
  return theme.paint("teal", text);
}

/**
 * Render the status bar for the current width. Segments with no real data
 * are absent, not zeroed (Absolute Rule #4). Lower-priority segments drop
 * whole as width shrinks — never truncated mid-token. Each segment carries
 * its own accent (branch cyan · model violet · context teal · cost orange);
 * separators stay dim, monochrome text is unchanged.
 */
export function renderStatusBar(data: StatusBarData, width: number, theme: Theme): string {
  const segments: string[] = [];

  const branchFull =
    data.branch !== undefined
      ? data.dirty && (data.dirty.added > 0 || data.dirty.removed > 0)
        ? `${theme.paint("cyan", data.branch)} ${theme.paint("success", `+${data.dirty.added}`)} ${theme.paint("error", `−${data.dirty.removed}`)}`
        : theme.paint("cyan", data.branch)
      : undefined;

  if (width < 60) {
    if (data.phase !== undefined) segments.push(renderPhaseRibbon(data.phase, theme, true));
    if (data.branch !== undefined) segments.push(theme.paint("cyan", data.branch));
    const ctx = contextSegment(data, theme, false);
    if (ctx !== undefined) segments.push(ctx);
  } else if (width < 80) {
    if (data.phase !== undefined) segments.push(renderPhaseRibbon(data.phase, theme, true));
    if (branchFull !== undefined) segments.push(branchFull);
    const alias = shortModel(data);
    if (alias !== undefined) segments.push(theme.paint("violet", alias));
    const ctx = contextSegment(data, theme, false);
    if (ctx !== undefined) segments.push(ctx);
  } else {
    // The cockpit (TUI v2 §3): phase ribbon left, then branch, model, gauge, cost.
    if (data.phase !== undefined) {
      segments.push(renderPhaseRibbon(data.phase, theme, width < 110));
    }
    if (branchFull !== undefined) segments.push(branchFull);
    const model = width < 100 ? shortModel(data) : data.model;
    if (model !== undefined) segments.push(theme.paint("violet", model));
    if (data.contextPct !== undefined && width >= 110) {
      segments.push(renderContextGauge(data.contextPct, theme));
    } else {
      const ctx = contextSegment(data, theme, true);
      if (ctx !== undefined) segments.push(ctx);
    }
    if (data.costUsd !== undefined) segments.push(theme.paint("orange", `$${data.costUsd.toFixed(2)}`));
    if (data.processCount !== undefined && data.processCount > 0) {
      segments.push(`${theme.paint("accent", "●")} ${data.processCount}`);
    }
    if (data.queuedCount !== undefined && data.queuedCount > 0) {
      segments.push(theme.paint("warning", `⋯ ${data.queuedCount} queued`));
    }
  }

  const bar = segments.join(theme.paint("dim", "  │  "));
  return truncateAnsi(" " + bar, width);
}