// src/components/MilestoneTimeline.js
import React, { useEffect, useState, useCallback } from 'react';

const today = new Date();

const MilestoneTimeline = ({ careerPathId, authFetch, activeView, setActiveView }) => {
  const [milestones, setMilestones] = useState({ Career: [], Financial: [] });
  const [newMilestone, setNewMilestone] = useState({
    title: '',
    description: '',
    date: '',
    progress: 0,
    newSalary: ''
  });
  const [showForm, setShowForm] = useState(false);
  const [editingMilestone, setEditingMilestone] = useState(null);

  /**
   * Fetch all milestones (and their tasks) for this careerPathId
   * Then categorize them by milestone_type: 'Career' or 'Financial'.
   */
  const fetchMilestones = useCallback(async () => {
    if (!careerPathId) return;

    try {
      const res = await authFetch(`/api/premium/milestones?careerPathId=${careerPathId}`);
      if (!res.ok) {
        console.error('Failed to fetch milestones. Status:', res.status);
        return;
      }
      const data = await res.json();
      if (!data.milestones) {
        console.warn('No milestones field in response:', data);
        return;
      }

      // data.milestones = [ { id, milestone_type, date, ..., tasks: [ ... ] }, ... ]
      console.log('Fetched milestones with tasks:', data.milestones);

      // Categorize by milestone_type
      const categorized = { Career: [], Financial: [] };
      data.milestones.forEach((m) => {
        if (categorized[m.milestone_type]) {
          categorized[m.milestone_type].push(m);
        } else {
          console.warn(`Unknown milestone type: ${m.milestone_type}`);
        }
      });

      setMilestones(categorized);
    } catch (err) {
      console.error('Failed to fetch milestones:', err);
    }
  }, [careerPathId, authFetch]);

  // Run fetchMilestones on mount or when careerPathId changes
  useEffect(() => {
    fetchMilestones();
  }, [fetchMilestones]);

  /**
   * Create or update a milestone.
   * If editingMilestone is set, we do PUT -> /api/premium/milestones/:id
   * Else we do POST -> /api/premium/milestone
   */
  const saveMilestone = async () => {
    if (!activeView) return;

    const url = editingMilestone
      ? `/api/premium/milestones/${editingMilestone.id}`
      : `/api/premium/milestone`;
    const method = editingMilestone ? 'PUT' : 'POST';

    const payload = {
      milestone_type: activeView,
      title: newMilestone.title,
      description: newMilestone.description,
      date: newMilestone.date,
      career_path_id: careerPathId,
      progress: newMilestone.progress,
      status: newMilestone.progress >= 100 ? 'completed' : 'planned',
      // Only include new_salary if it's a Financial milestone
      new_salary: activeView === 'Financial' && newMilestone.newSalary
        ? parseFloat(newMilestone.newSalary)
        : null
    };

    try {
      console.log('Sending request:', method, url, payload);
      const res = await authFetch(url, {
        method,
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(payload)
      });

      if (!res.ok) {
        const errorData = await res.json();
        console.error('Failed to save milestone:', errorData);
        alert(errorData.error || 'Error saving milestone');
        return;
      }

      const savedMilestone = await res.json();
      console.log('Milestone saved/updated:', savedMilestone);

      // Update local state so we don't have to refetch everything
      setMilestones((prev) => {
        const updated = { ...prev };
        // If editing, replace existing; else push new
        if (editingMilestone) {
          updated[activeView] = updated[activeView].map((m) =>
            m.id === editingMilestone.id ? savedMilestone : m
          );
        } else {
          updated[activeView].push(savedMilestone);
        }
        return updated;
      });

      // Reset form
      setShowForm(false);
      setEditingMilestone(null);
      setNewMilestone({
        title: '',
        description: '',
        date: '',
        progress: 0,
        newSalary: ''
      });
    } catch (err) {
      console.error('Error saving milestone:', err);
    }
  };

  /**
   * Figure out the timeline's "end" date by scanning all milestones.
   */
  const allMilestonesCombined = [...milestones.Career, ...milestones.Financial];
  const lastDate = allMilestonesCombined.reduce((latest, m) => {
    const d = new Date(m.date);
    return d > latest ? d : latest;
  }, today);

  const calcPosition = (dateString) => {
    const start = today.getTime();
    const end = lastDate.getTime();
    const dateVal = new Date(dateString).getTime();
    if (end === start) return 0; // edge case if only one date
    const ratio = (dateVal - start) / (end - start);
    return Math.min(Math.max(ratio * 100, 0), 100);
  };

  // If activeView not set or the array is missing, show a loading or empty state
  if (!activeView || !milestones[activeView]) {
    return (
      <div className="milestone-timeline">
        <p>Loading or no milestones in this view...</p>
      </div>
    );
  }

  return (
    <div className="milestone-timeline">
      {/* View selector buttons */}
      <div className="view-selector">
        {['Career', 'Financial'].map((view) => (
          <button
            key={view}
            className={activeView === view ? 'active' : ''}
            onClick={() => setActiveView(view)}
          >
            {view}
          </button>
        ))}
      </div>

      <button
        onClick={() => {
          if (showForm) {
            // Cancel form
            setShowForm(false);
            setEditingMilestone(null);
            setNewMilestone({
              title: '',
              description: '',
              date: '',
              progress: 0,
              newSalary: ''
            });
          } else {
            // Show form
            setShowForm(true);
          }
        }}
      >
        {showForm ? 'Cancel' : '+ New Milestone'}
      </button>

      {showForm && (
        <div className="form">
          <input
            type="text"
            placeholder="Title"
            value={newMilestone.title}
            onChange={(e) => setNewMilestone({ ...newMilestone, title: e.target.value })}
          />
          <input
            type="text"
            placeholder="Description"
            value={newMilestone.description}
            onChange={(e) => setNewMilestone({ ...newMilestone, description: e.target.value })}
          />
          <input
            type="date"
            value={newMilestone.date}
            onChange={(e) => setNewMilestone({ ...newMilestone, date: e.target.value })}
          />
          <input
            type="number"
            placeholder="Progress (%)"
            value={newMilestone.progress}
            onChange={(e) =>
              setNewMilestone({
                ...newMilestone,
                progress: parseInt(e.target.value, 10)
              })
            }
          />
          {activeView === 'Financial' && (
            <div>
              <input
                type="number"
                placeholder="Full New Salary (e.g., 70000)"
                value={newMilestone.newSalary}
                onChange={(e) =>
                  setNewMilestone({ ...newMilestone, newSalary: e.target.value })
                }
              />
              <p>Enter the full new salary (not just the increase) after the milestone occurs.</p>
            </div>
          )}
          <button onClick={saveMilestone}>
            {editingMilestone ? 'Update' : 'Add'} Milestone
          </button>
        </div>
      )}

      {/* Timeline rendering */}
      <div className="milestone-timeline-container">
        <div className="milestone-timeline-line" />
        {milestones[activeView].map((m) => {
          const leftPos = calcPosition(m.date);
          return (
            <div
              key={m.id}
              className="milestone-timeline-post"
              style={{ left: `${leftPos}%` }}
              onClick={() => {
                // Clicking a milestone => edit it
                setEditingMilestone(m);
                setNewMilestone({
                  title: m.title,
                  description: m.description,
                  date: m.date,
                  progress: m.progress,
                  newSalary: m.new_salary || ''
                });
                setShowForm(true);
              }}
            >
              <div className="milestone-timeline-dot" />
              <div className="milestone-content">
                <div className="title">{m.title}</div>
                {m.description && <p>{m.description}</p>}
                <div className="progress-bar">
                  <div className="progress" style={{ width: `${m.progress}%` }} />
                </div>
                <div className="date">{m.date}</div>

                {/* If the milestone has tasks */}
                {m.tasks && m.tasks.length > 0 && (
                  <ul>
                    {m.tasks.map((t) => (
                      <li key={t.id}>{t.title}</li>
                    ))}
                  </ul>
                )}
              </div>
            </div>
          );
        })}
      </div>
    </div>
  );
};

export default MilestoneTimeline;