import { useState } from 'react';
import {
  INJURY_TRACKERS,
  TRACKED_GRADE_SCALE,
  capGradeAtMax,
  getGradeScore,
} from '../utils/weekUtils';
import './SessionLog.css';

const SESSION_TYPES = {
  lead: 'Lead',
  bouldering: 'Bouldering',
};

function getDuringPain(session, trackerKey) {
  return session[`${trackerKey}_during`] ?? session[`${trackerKey}_pain`] ?? '';
}

function getAfterPain(session, trackerKey) {
  return session[`${trackerKey}_after`] ?? '';
}

function SessionLog({ sessions, onEditSession, onDeleteSession }) {
  const [editingId, setEditingId] = useState(null);
  const [editForm, setEditForm] = useState({});

  if (!sessions || sessions.length === 0) {
    return (
      <div className="session-log card">
        <h2>Session History</h2>
        <p className="empty-message">No climbing sessions logged yet. Add your first one above.</p>
      </div>
    );
  }

  const sortedSessions = [...sessions].sort((a, b) => b.date.localeCompare(a.date));

  function formatDate(dateString) {
    const date = new Date(`${dateString}T00:00:00`);
    return date.toLocaleDateString('en-US', { weekday: 'short', month: 'short', day: 'numeric' });
  }

  function handleEdit(session) {
    setEditingId(session.id);
    setEditForm({
      date: session.date,
      session_type: session.session_type || 'bouldering',
      routes_count: session.routes_count,
      max_grade: session.max_grade || '',
      rpe: session.rpe || 5,
      left_elbow_during: getDuringPain(session, 'left_elbow'),
      left_elbow_after: getAfterPain(session, 'left_elbow'),
      right_shoulder_during: getDuringPain(session, 'right_shoulder'),
      right_shoulder_after: getAfterPain(session, 'right_shoulder'),
      notes: session.notes || '',
    });
  }

  function handleSave() {
    const routes = parseInt(editForm.routes_count, 10);
    const rpe = parseInt(editForm.rpe, 10);
    const maxGrade = capGradeAtMax(editForm.max_grade);
    const maxGradeScore = getGradeScore(maxGrade);
    const leftElbowDuring = editForm.left_elbow_during === '' ? null : Number(editForm.left_elbow_during);
    const leftElbowAfter = editForm.left_elbow_after === '' ? null : Number(editForm.left_elbow_after);
    const rightShoulderDuring = editForm.right_shoulder_during === '' ? null : Number(editForm.right_shoulder_during);
    const rightShoulderAfter = editForm.right_shoulder_after === '' ? null : Number(editForm.right_shoulder_after);

    if (
      !editForm.date ||
      Number.isNaN(routes) ||
      routes <= 0 ||
      Number.isNaN(rpe) ||
      rpe < 1 ||
      rpe > 10 ||
      !maxGrade ||
      maxGradeScore == null ||
      (leftElbowDuring != null && (Number.isNaN(leftElbowDuring) || leftElbowDuring < 0 || leftElbowDuring > 10)) ||
      (leftElbowAfter != null && (Number.isNaN(leftElbowAfter) || leftElbowAfter < 0 || leftElbowAfter > 10)) ||
      (rightShoulderDuring != null && (Number.isNaN(rightShoulderDuring) || rightShoulderDuring < 0 || rightShoulderDuring > 10)) ||
      (rightShoulderAfter != null && (Number.isNaN(rightShoulderAfter) || rightShoulderAfter < 0 || rightShoulderAfter > 10))
    ) {
      return;
    }

    const sessionType = SESSION_TYPES[editForm.session_type] ? editForm.session_type : 'bouldering';

    onEditSession(editingId, {
      date: editForm.date,
      session_type: sessionType,
      routes_count: routes,
      max_grade: maxGrade,
      rpe,
      left_elbow_during: leftElbowDuring,
      left_elbow_after: leftElbowAfter,
      right_shoulder_during: rightShoulderDuring,
      right_shoulder_after: rightShoulderAfter,
      // Clear legacy single-value fields after editing.
      left_elbow_pain: null,
      right_shoulder_pain: null,
      notes: (editForm.notes || '').trim(),
    });

    setEditingId(null);
  }

  function handleCancel() {
    setEditingId(null);
  }

  function handleDelete(id) {
    if (window.confirm('Delete this climbing session?')) {
      onDeleteSession(id);
    }
  }

  function handleKeyDown(event) {
    if (event.key === 'Enter') handleSave();
    if (event.key === 'Escape') handleCancel();
  }

  function formatSessionType(type) {
    return SESSION_TYPES[type] || '—';
  }

  return (
    <div className="session-log card">
      <h2>Session History</h2>
      <div className="table-wrapper">
        <table>
          <thead>
            <tr>
              <th>Date</th>
              <th>Type</th>
              <th>Routes</th>
              <th>Max Grade</th>
              <th>RPE</th>
              <th>Load</th>
              <th>Injury (D/A)</th>
              <th>Notes</th>
              <th></th>
            </tr>
          </thead>
          <tbody>
            {sortedSessions.map((session) => {
              if (editingId === session.id) {
                const previewRoutes = parseInt(editForm.routes_count, 10) || 0;
                const previewRpe = parseInt(editForm.rpe, 10) || 0;

                return (
                  <tr key={session.id} className="editing-row">
                    <td>
                      <input
                        type="date"
                        value={editForm.date}
                        onChange={(event) => setEditForm({ ...editForm, date: event.target.value })}
                        onKeyDown={handleKeyDown}
                      />
                    </td>
                    <td>
                      <select
                        value={editForm.session_type}
                        onChange={(event) => setEditForm({ ...editForm, session_type: event.target.value })}
                      >
                        <option value="lead">Lead</option>
                        <option value="bouldering">Bouldering</option>
                      </select>
                    </td>
                    <td>
                      <input
                        type="number"
                        min="1"
                        step="1"
                        value={editForm.routes_count}
                        onChange={(event) => setEditForm({ ...editForm, routes_count: event.target.value })}
                        onKeyDown={handleKeyDown}
                      />
                    </td>
                    <td>
                      <input
                        type="text"
                        value={editForm.max_grade}
                        onChange={(event) => setEditForm({ ...editForm, max_grade: event.target.value })}
                        onBlur={() => setEditForm((prev) => ({ ...prev, max_grade: capGradeAtMax(prev.max_grade) }))}
                        list={`grade-scale-list-${session.id}`}
                        onKeyDown={handleKeyDown}
                        placeholder="e.g. 6B+ (max 7B)"
                      />
                      <datalist id={`grade-scale-list-${session.id}`}>
                        {TRACKED_GRADE_SCALE.map((grade) => (
                          <option key={grade} value={grade} />
                        ))}
                      </datalist>
                    </td>
                    <td>
                      <input
                        type="number"
                        min="1"
                        step="1"
                        max="10"
                        value={editForm.rpe}
                        onChange={(event) => setEditForm({ ...editForm, rpe: event.target.value })}
                        onKeyDown={handleKeyDown}
                      />
                    </td>
                    <td className="computed-cell">{(previewRoutes * previewRpe).toFixed(0)}</td>
                    <td>
                      <div className="injury-edit-stack">
                        {INJURY_TRACKERS.map((tracker) => (
                          <label key={tracker.key} className="injury-edit-row">
                            <span>{tracker.label}</span>
                            <div className="injury-edit-phase">
                              <input
                                type="number"
                                min="0"
                                max="10"
                                step="1"
                                value={editForm[`${tracker.key}_during`]}
                                onChange={(event) => setEditForm({ ...editForm, [`${tracker.key}_during`]: event.target.value })}
                                onKeyDown={handleKeyDown}
                                placeholder="D"
                              />
                              <span>/</span>
                              <input
                                type="number"
                                min="0"
                                max="10"
                                step="1"
                                value={editForm[`${tracker.key}_after`]}
                                onChange={(event) => setEditForm({ ...editForm, [`${tracker.key}_after`]: event.target.value })}
                                onKeyDown={handleKeyDown}
                                placeholder="A"
                              />
                            </div>
                          </label>
                        ))}
                      </div>
                    </td>
                    <td>
                      <input
                        type="text"
                        value={editForm.notes}
                        onChange={(event) => setEditForm({ ...editForm, notes: event.target.value })}
                        onKeyDown={handleKeyDown}
                        placeholder="Notes..."
                      />
                    </td>
                    <td className="action-buttons">
                      <button className="btn-save" onClick={handleSave} aria-label="Save">✓</button>
                      <button className="btn-cancel" onClick={handleCancel} aria-label="Cancel">✕</button>
                    </td>
                  </tr>
                );
              }

              return (
                <tr key={session.id}>
                  <td>{formatDate(session.date)}</td>
                  <td>{formatSessionType(session.session_type)}</td>
                  <td>{session.routes_count}</td>
                  <td>{session.max_grade || '—'}</td>
                  <td>{session.rpe}/10</td>
                  <td>{(session.routes_count * session.rpe).toFixed(0)}</td>
                  <td className="injury-display-cell">
                    <div>
                      LE: {session.left_elbow_during ?? session.left_elbow_pain ?? '—'}/{session.left_elbow_after ?? '—'}
                    </div>
                    <div>
                      RS: {session.right_shoulder_during ?? session.right_shoulder_pain ?? '—'}/{session.right_shoulder_after ?? '—'}
                    </div>
                  </td>
                  <td className="notes-cell">{session.notes || ''}</td>
                  <td className="action-buttons">
                    <button className="btn-edit" onClick={() => handleEdit(session)} aria-label="Edit session">✎</button>
                    <button className="btn-delete" onClick={() => handleDelete(session.id)} aria-label="Delete session">✕</button>
                  </td>
                </tr>
              );
            })}
          </tbody>
        </table>
      </div>
    </div>
  );
}

export default SessionLog;