import { useState, useCallback } from "react";
import { Play, Pause, Pencil, Trash2, Clock, CheckCircle, XCircle, ChevronDown, ChevronUp, Layers } from "lucide-react";
import type { ScheduledTask, AutomationRunResult, AutomationStepResult } from "@fusion/core";

/**
 * Format a duration in milliseconds to a human-readable string.
 */
function formatDurationMs(ms: number): string {
  if (ms < 1000) return `${ms}ms`;
  const seconds = Math.floor(ms / 1000);
  if (seconds < 60) return `${seconds}s`;
  const minutes = Math.floor(seconds / 60);
  const remainingSeconds = seconds % 60;
  if (minutes < 60) return remainingSeconds > 0 ? `${minutes}m ${remainingSeconds}s` : `${minutes}m`;
  const hours = Math.floor(minutes / 60);
  const remainingMinutes = minutes % 60;
  return remainingMinutes > 0 ? `${hours}h ${remainingMinutes}m` : `${hours}h`;
}

/**
 * Format an ISO timestamp to a relative time string.
 */
function relativeTime(iso: string): string {
  const now = Date.now();
  const then = new Date(iso).getTime();
  const diffMs = now - then;

  // Future
  if (diffMs < 0) {
    const absDiff = Math.abs(diffMs);
    if (absDiff < 60_000) return "in a moment";
    if (absDiff < 3_600_000) return `in ${Math.floor(absDiff / 60_000)}m`;
    if (absDiff < 86_400_000) return `in ${Math.floor(absDiff / 3_600_000)}h`;
    return `in ${Math.floor(absDiff / 86_400_000)}d`;
  }

  // Past
  if (diffMs < 60_000) return "just now";
  if (diffMs < 3_600_000) return `${Math.floor(diffMs / 60_000)}m ago`;
  if (diffMs < 86_400_000) return `${Math.floor(diffMs / 3_600_000)}h ago`;
  return `${Math.floor(diffMs / 86_400_000)}d ago`;
}

const SCHEDULE_TYPE_COLORS: Record<string, string> = {
  hourly: "var(--color-blue, #3b82f6)",
  daily: "var(--color-green, #22c55e)",
  weekly: "var(--color-purple, #a855f7)",
  monthly: "var(--color-orange, #f97316)",
  custom: "var(--color-gray, #6b7280)",
  every15Minutes: "var(--color-cyan, #06b6d4)",
  every30Minutes: "var(--color-teal, #14b8a6)",
  every2Hours: "var(--color-indigo, #6366f1)",
  every6Hours: "var(--color-rose, #f43f5e)",
  every12Hours: "var(--color-amber, #f59e0b)",
  weekdays: "var(--color-emerald, #10b981)",
};

interface ScheduleCardProps {
  schedule: ScheduledTask;
  onEdit: (schedule: ScheduledTask) => void;
  onDelete: (schedule: ScheduledTask) => void;
  onRun: (schedule: ScheduledTask) => void;
  onToggle: (schedule: ScheduledTask) => void;
  /** Whether a manual run is currently in progress. */
  running?: boolean;
}

function RunResultBadge({ result }: { result: AutomationRunResult }) {
  const duration = new Date(result.completedAt).getTime() - new Date(result.startedAt).getTime();
  return (
    <span className={`schedule-run-badge ${result.success ? "success" : "failure"}`}>
      {result.success ? (
        <CheckCircle size={12} />
      ) : (
        <XCircle size={12} />
      )}
      <span>{result.success ? "Success" : "Failed"}</span>
      <span className="schedule-run-duration">{formatDurationMs(duration)}</span>
    </span>
  );
}

function StepResultIndicator({ stepResults }: { stepResults: AutomationStepResult[] }) {
  return (
    <span className="step-results-indicator">
      {stepResults.map((sr) => (
        <span
          key={sr.stepId}
          className={`step-result-dot ${sr.success ? "success" : "failure"}`}
          title={`${sr.stepName}: ${sr.success ? "success" : "failed"}`}
        />
      ))}
    </span>
  );
}

function RunHistoryItem({ result, index }: { result: AutomationRunResult; index: number }) {
  const [expanded, setExpanded] = useState(false);
  const duration = new Date(result.completedAt).getTime() - new Date(result.startedAt).getTime();
  const hasStepResults = result.stepResults && result.stepResults.length > 0;

  return (
    <div className="schedule-history-item">
      <button
        className="schedule-history-header"
        onClick={() => setExpanded(!expanded)}
        aria-expanded={expanded}
        aria-label={`Run #${index + 1}: ${result.success ? "succeeded" : "failed"} ${relativeTime(result.startedAt)}`}
      >
        <span className={`schedule-history-status ${result.success ? "success" : "failure"}`}>
          {result.success ? <CheckCircle size={12} /> : <XCircle size={12} />}
        </span>
        <span className="schedule-history-time">{relativeTime(result.startedAt)}</span>
        {hasStepResults && <StepResultIndicator stepResults={result.stepResults!} />}
        <span className="schedule-history-duration">{formatDurationMs(duration)}</span>
        {expanded ? <ChevronUp size={12} /> : <ChevronDown size={12} />}
      </button>
      {expanded && (
        <div className="schedule-history-detail">
          {hasStepResults && (
            <div className="schedule-step-results">
              {result.stepResults!.map((sr) => (
                <div key={sr.stepId} className={`schedule-step-result ${sr.success ? "success" : "failure"}`}>
                  <span className="schedule-step-result-status">
                    {sr.success ? <CheckCircle size={10} /> : <XCircle size={10} />}
                  </span>
                  <span className="schedule-step-result-name">{sr.stepName}</span>
                  {sr.error && <span className="schedule-step-result-error">{sr.error}</span>}
                </div>
              ))}
            </div>
          )}
          {result.output && (
            <pre className="schedule-history-output">{result.output}</pre>
          )}
          {result.error && (
            <div className="schedule-history-error">{result.error}</div>
          )}
        </div>
      )}
    </div>
  );
}

export function ScheduleCard({ schedule, onEdit, onDelete, onRun, onToggle, running }: ScheduleCardProps) {
  const [showHistory, setShowHistory] = useState(false);

  const handleDelete = useCallback(() => {
    if (window.confirm(`Delete schedule "${schedule.name}"? This cannot be undone.`)) {
      onDelete(schedule);
    }
  }, [schedule, onDelete]);

  const typeColor = SCHEDULE_TYPE_COLORS[schedule.scheduleType] ?? SCHEDULE_TYPE_COLORS.custom;

  return (
    <div className={`schedule-card${schedule.enabled ? "" : " disabled"}`}>
      <div className="schedule-card-header">
        <div className="schedule-card-info">
          <div className="schedule-card-name-row">
            <span className="schedule-card-name">{schedule.name}</span>
            <span
              className="schedule-type-badge"
              style={{ borderColor: typeColor, color: typeColor }}
            >
              {schedule.scheduleType}
            </span>
          </div>
          {schedule.description && (
            <p className="schedule-card-description">{schedule.description}</p>
          )}
        </div>
        <div className="schedule-card-actions">
          <button
            className="btn-icon"
            onClick={() => onRun(schedule)}
            disabled={running}
            title={running ? "Running…" : "Run now"}
            aria-label={running ? "Running…" : `Run ${schedule.name} now`}
          >
            <Play size={14} />
          </button>
          <button
            className="btn-icon"
            onClick={() => onToggle(schedule)}
            title={schedule.enabled ? "Disable" : "Enable"}
            aria-label={schedule.enabled ? `Disable ${schedule.name}` : `Enable ${schedule.name}`}
            aria-pressed={schedule.enabled}
          >
            {schedule.enabled ? <Pause size={14} /> : <Play size={14} />}
          </button>
          <button
            className="btn-icon"
            onClick={() => onEdit(schedule)}
            title="Edit"
            aria-label={`Edit ${schedule.name}`}
          >
            <Pencil size={14} />
          </button>
          <button
            className="btn-icon"
            onClick={handleDelete}
            title="Delete"
            aria-label={`Delete ${schedule.name}`}
          >
            <Trash2 size={14} />
          </button>
        </div>
      </div>

      <div className="schedule-card-meta">
        {schedule.steps && schedule.steps.length > 0 ? (
          <div className="schedule-meta-item">
            <Layers size={12} />
            <span className="schedule-steps-badge">{schedule.steps.length} step{schedule.steps.length !== 1 ? "s" : ""}</span>
          </div>
        ) : (
          <div className="schedule-meta-item schedule-meta-command-preview" title={schedule.command}>
            <code className="schedule-command-preview">{schedule.command}</code>
          </div>
        )}
        <div className="schedule-meta-item">
          <Clock size={12} />
          <code className="schedule-cron">{schedule.cronExpression}</code>
        </div>
        {schedule.nextRunAt && schedule.enabled && (
          <div className="schedule-meta-item">
            <span className="schedule-meta-label">Next:</span>
            <span title={schedule.nextRunAt}>{relativeTime(schedule.nextRunAt)}</span>
          </div>
        )}
        {schedule.lastRunAt && (
          <div className="schedule-meta-item">
            <span className="schedule-meta-label">Last:</span>
            <span title={schedule.lastRunAt}>{relativeTime(schedule.lastRunAt)}</span>
          </div>
        )}
        {schedule.lastRunResult && (
          <RunResultBadge result={schedule.lastRunResult} />
        )}
        <div className="schedule-meta-item">
          <span className="schedule-meta-label">Runs:</span>
          <span>{schedule.runCount}</span>
        </div>
      </div>

      {schedule.runHistory.length > 0 && (
        <div className="schedule-card-history">
          <button
            className="schedule-history-toggle"
            onClick={() => setShowHistory((h) => !h)}
            aria-expanded={showHistory}
          >
            {showHistory ? <ChevronUp size={12} /> : <ChevronDown size={12} />}
            <span>Run History ({schedule.runHistory.length})</span>
          </button>
          {showHistory && (
            <div className="schedule-history-list">
              {schedule.runHistory.slice(0, 10).map((result, i) => (
                <RunHistoryItem key={`${result.startedAt}-${i}`} result={result} index={i} />
              ))}
              {schedule.runHistory.length > 10 && (
                <div className="schedule-history-more">
                  …and {schedule.runHistory.length - 10} more
                </div>
              )}
            </div>
          )}
        </div>
      )}
    </div>
  );
}