/**
 * Mission Control TUI Progress Bar
 * 
 * Bottom bar displaying:
 * - Visual progress bar using block characters
 * - Percentage completion
 * - Task count (completed/total)
 * 
 * Block characters for progress bar:
 * - Full: \u2588 (█)
 * - Empty: \u2591 (░)
 */

import type { Theme } from "@mariozechner/pi-coding-agent";
import type { Run } from "../state.js";
import { truncateToWidth } from "@mariozechner/pi-tui";

// Block characters for progress bar
const BLOCK_FULL = "\u2588";  // █
const BLOCK_EMPTY = "\u2591"; // ░

export interface ProgressBarProps {
  run: Run | null;
  statusMessage: string;
}

/**
 * Count completed and total tasks across all phases
 */
function countTasks(run: Run): { completed: number; total: number; phaseCompleted: number; phaseTotal: number } {
  let completed = 0;
  let total = 0;
  let phaseCompleted = 0;
  let phaseTotal = run.phases.length;
  
  for (const phase of run.phases) {
    if (phase.status === "done") {
      phaseCompleted++;
    }
    for (const task of phase.tasks) {
      if (task.status === "removed") continue;
      total++;
      if (task.status === "done") {
        completed++;
      }
    }
  }
  
  return { completed, total, phaseCompleted, phaseTotal };
}

/**
 * Render a progress bar string
 */
function renderProgressBar(percent: number, width: number): string {
  if (width < 3) return "";
  
  const filled = Math.round((percent / 100) * width);
  const empty = width - filled;
  
  return BLOCK_FULL.repeat(filled) + BLOCK_EMPTY.repeat(empty);
}

/**
 * Render the progress bar component
 */
export function renderProgressBarComponent(
  width: number,
  props: ProgressBarProps,
  theme: Theme
): string[] {
  const { run } = props;
  const lines: string[] = [];

  if (!run || run.phases.length === 0) {
    const suffix = "[0/0 Tasks]";
    const progressBar = renderProgressBar(0, Math.max(0, width - suffix.length - 4));
    lines.push(truncateToWidth(theme.fg("muted", `[${progressBar}] ${suffix}`), width));
    return lines;
  }
  
  // Count tasks
  const { completed, total } = countTasks(run);
  const percent = total > 0 ? Math.round((completed / total) * 100) : 0;
  const suffix = `[${completed}/${total} Tasks]`;
  const barWidth = Math.max(0, width - suffix.length - 4);
  const progressBar = renderProgressBar(percent, barWidth);
  lines.push(truncateToWidth(theme.fg("accent", `[${progressBar}] ${suffix}`), width));
  
  return lines;
}

/**
 * Progress bar component class
 */
export class ProgressBarComponent {
  private props: ProgressBarProps;
  private cachedWidth?: number;
  private cachedLines?: string[];
  
  constructor(run: Run | null = null, statusMessage = "") {
    this.props = { run, statusMessage };
  }
  
  update(run: Run | null, statusMessage?: string): void {
    this.props.run = run;
    if (statusMessage !== undefined) {
      this.props.statusMessage = statusMessage;
    }
    this.invalidate();
  }
  
  updateStatus(message: string): void {
    this.props.statusMessage = message;
    this.invalidate();
  }
  
  getCompletionPercent(): number {
    const { run } = this.props;
    if (!run) return 0;
    
    let completed = 0;
    let total = 0;
    
    for (const phase of run.phases) {
      for (const task of phase.tasks) {
        if (task.status === "removed") continue;
        total++;
        if (task.status === "done") {
          completed++;
        }
      }
    }
    
    return total > 0 ? Math.round((completed / total) * 100) : 0;
  }
  
  render(width: number, theme: Theme): string[] {
    if (this.cachedLines && this.cachedWidth === width) {
      return this.cachedLines;
    }
    
    this.cachedLines = renderProgressBarComponent(width, this.props, theme);
    this.cachedWidth = width;
    return this.cachedLines;
  }
  
  invalidate(): void {
    this.cachedWidth = undefined;
    this.cachedLines = undefined;
  }
}