import { VERSION, type Theme } from "@earendil-works/pi-coding-agent";

import { renderAnimation, type LogoAnimation } from "./logos/animations.js";
import { buildResponsiveLogoHeaderLines } from "./logos/text-table.js";

const LOGO_GAP = 2;
const HEADER_LEFT_PADDING = 2;
const MIN_CONTENT_WIDTH = 24;
const LIFTED_HELP_RESERVED_LINES = 3;
const MINI_LOGO_LINES = ["█▀█", "█▀ █"];

const COMPACT_SHORTCUTS = "escape interrupt · ctrl+c/ctrl+d clear/exit · / commands · ! bash · ctrl+o more";
const MINI_SHORTCUTS = "escape to interrupt";
const EXPANDED_HELP_SHORTCUTS = [
  "escape to interrupt",
  "ctrl+c to clear",
  "ctrl+c twice to exit",
  "ctrl+d to exit (empty)",
  "ctrl+z to suspend",
  "ctrl+k to delete to end",
  "shift+tab to cycle thinking level",
  "ctrl+p/shift+ctrl+p to cycle models",
  "ctrl+l to select model",
  "ctrl+o to expand tools",
  "ctrl+t to expand thinking",
  "ctrl+g for external editor",
  "/ for commands",
  "! to run bash",
  "!! to run bash (no context)",
  "alt+enter to queue follow-up",
  "alt+up to edit all queued messages",
  "ctrl+v to paste image",
  "drop files to attach",
];

type HeaderTheme = Pick<Theme, "fg" | "bold">;

type HeaderTui = {
  requestRender(): void;
};

interface HeaderComponentOptions {
  tui: HeaderTui;
  theme: HeaderTheme;
  logoLines: string[];
  animation: LogoAnimation;
}

export interface HeaderComponent {
  render(width: number): string[];
  setExpanded(value: boolean): void;
  setLogoAnimation(logoLines: string[], animation: LogoAnimation): void;
  invalidate(): void;
  dispose(): void;
  stopAnimation(): void;
}

function buildCompactLines(titleLine: string, onboardingLine: string, theme: HeaderTheme): string[] {
  return [
    titleLine,
    theme.fg("muted", COMPACT_SHORTCUTS),
    theme.fg("dim", "Press ctrl+o to show full startup help and loaded resources."),
    "",
    onboardingLine,
  ];
}

function buildExpandedHelpLines(theme: HeaderTheme): string[] {
  return EXPANDED_HELP_SHORTCUTS.map((shortcut) => theme.fg("muted", shortcut));
}

export function createHeaderComponent({ tui, theme, logoLines, animation }: HeaderComponentOptions): HeaderComponent {
  let expanded = false;
  let selectedLogoLines = logoLines;
  let selectedAnimation = animation;
  let frameCount = 0;
  let animationStopped = selectedAnimation.id === "static";
  let interval: ReturnType<typeof setInterval> | undefined;

  const titleLine = `${theme.bold(theme.fg("accent", "pi"))}${theme.fg("dim", ` v${VERSION}`)}`;
  const miniHelpLine = theme.fg("muted", MINI_SHORTCUTS);
  const onboardingLine = theme.fg("dim", "Pi can explain its own features and look up its docs. Ask it how to use or extend Pi.");
  const compactLines = buildCompactLines(titleLine, onboardingLine, theme);
  const expandedHelpLines = buildExpandedHelpLines(theme);

  function stopInterval(): void {
    if (!interval) return;

    clearInterval(interval);
    interval = undefined;
  }

  function startInterval(): void {
    if (interval) return;

    interval = setInterval(() => {
      frameCount += 1;
      tui.requestRender();
    }, 120);
  }

  if (!animationStopped) {
    startInterval();
  }

  return {
    render(width: number): string[] {
      const logoLines = renderAnimation(selectedAnimation, {
        logoLines: selectedLogoLines,
        frameCount,
        colorize: animationStopped ? undefined : (color, value) => theme.fg(color, value),
      });

      return buildResponsiveLogoHeaderLines({
        width,
        expanded,
        logoLines,
        miniLogoLines: MINI_LOGO_LINES,
        titleLine,
        miniHelpLine,
        onboardingLine,
        compactLines,
        expandedHelpLines,
        gap: LOGO_GAP,
        leftPadding: HEADER_LEFT_PADDING,
        minContentWidth: MIN_CONTENT_WIDTH,
        liftedHelpReservedLines: LIFTED_HELP_RESERVED_LINES,
      });
    },

    setExpanded(value: boolean): void {
      if (expanded === value) return;

      expanded = value;
      tui.requestRender();
    },

    setLogoAnimation(nextLogoLines: string[], nextAnimation: LogoAnimation): void {
      selectedLogoLines = nextLogoLines;
      selectedAnimation = nextAnimation;
      frameCount = 0;
      animationStopped = nextAnimation.id === "static";

      if (animationStopped) {
        stopInterval();
      } else {
        startInterval();
      }

      tui.requestRender();
    },

    invalidate(): void {
      tui.requestRender();
    },

    stopAnimation(): void {
      if (animationStopped) return;

      animationStopped = true;
      stopInterval();
      tui.requestRender();
    },

    dispose(): void {
      stopInterval();
    },
  };
}