/* ObsiGate — Graph View: interactive file/folder relationship visualization */
import { api } from './auth.js';
import { safeCreateIcons } from './utils.js';
import { openFile } from './viewer.js';

// ---------------------------------------------------------------------------
// Graph View Manager — Interactive file/folder relationship visualization
// ---------------------------------------------------------------------------

export const GraphViewManager = {
  _canvas: null,
  _ctx: null,
  _nodes: [],
  _edges: [],
  _offsetX: 0,
  _offsetY: 0,
  _zoom: 1,
  _dragging: false,
  _dragNode: null,
  _panning: false,
  _panStartX: 0,
  _panStartY: 0,
  _animFrame: null,
  _vault: null,
  _path: null,
  _nodePositions: {},
  _width: 0,
  _height: 0,

  async open(vault, path, type) {
    this._vault = vault;
    this._path = path;

    const modal = document.getElementById("graph-modal");
    const title = document.getElementById("graph-title");
    const info = document.getElementById("graph-info");
    const canvas = document.getElementById("graph-canvas");

    if (!modal || !canvas) return;

    title.textContent = `Vue Graphique — ${vault}${path ? "/" + path : ""}`;
    info.textContent = "Chargement...";
    modal.classList.add("active");

    this._canvas = canvas;
    this._ctx = canvas.getContext("2d");
    this._resetView();

    // Fetch graph data
    try {
      const data = await api(`/api/graph/${encodeURIComponent(vault)}?path=${encodeURIComponent(path)}&depth=1`);
      this._nodes = data.nodes || [];
      this._edges = data.edges || [];
      info.textContent = `${this._nodes.length} nœuds, ${this._edges.length} liens`;
      this._initLayout();
      this._startRender();
    } catch (err) {
      info.textContent = "Erreur de chargement";
      console.error("Graph error:", err);
    }

    safeCreateIcons();
  },

  close() {
    const modal = document.getElementById("graph-modal");
    if (modal) modal.classList.remove("active");
    if (this._animFrame) {
      cancelAnimationFrame(this._animFrame);
      this._animFrame = null;
    }
  },

  _resetView() {
    this._offsetX = 0;
    this._offsetY = 0;
    this._zoom = 1;
    this._nodePositions = {};
  },

  _initLayout() {
    const w = this._canvas.parentElement.clientWidth;
    const h = this._canvas.parentElement.clientHeight;
    this._canvas.width = w * devicePixelRatio;
    this._canvas.height = h * devicePixelRatio;
    this._canvas.style.width = w + "px";
    this._canvas.style.height = h + "px";
    this._width = w;
    this._height = h;
    this._ctx.scale(devicePixelRatio, devicePixelRatio);

    // Position nodes in a circle initially
    const cx = w / 2;
    const cy = h / 2;
    const radius = Math.min(w, h) * 0.35;

    this._nodes.forEach((node, i) => {
      const angle = (2 * Math.PI * i) / this._nodes.length;
      this._nodePositions[node.id] = {
        x: cx + radius * Math.cos(angle),
        y: cy + radius * Math.sin(angle),
        vx: 0,
        vy: 0,
      };
    });
  },

  _startRender() {
    const self = this;
    let lastTime = 0;

    const loop = (time) => {
      const dt = Math.min((time - lastTime) / 1000, 0.1);
      lastTime = time;
      self._simulate(dt);
      self._draw();
      self._animFrame = requestAnimationFrame(loop);
    };

    this._animFrame = requestAnimationFrame(loop);
  },

  _simulate(dt) {
    if (this._dragging || this._dragNode) return;

    const positions = this._nodePositions;
    const cx = this._width / 2;
    const cy = this._height / 2;

    // Spring forces (edges)
    for (const edge of this._edges) {
      const a = positions[edge.source];
      const b = positions[edge.target];
      if (!a || !b) continue;

      const dx = b.x - a.x;
      const dy = b.y - a.y;
      const dist = Math.sqrt(dx * dx + dy * dy) || 1;
      const targetLen = 80;
      const force = (dist - targetLen) * 0.01;
      const fx = (dx / dist) * force;
      const fy = (dy / dist) * force;

      a.vx += fx;
      a.vy += fy;
      b.vx -= fx;
      b.vy -= fy;
    }

    // Repulsion between all nodes
    for (const n1 of this._nodes) {
      for (const n2 of this._nodes) {
        if (n1.id === n2.id) continue;
        const a = positions[n1.id];
        const b = positions[n2.id];
        if (!a || !b) continue;

        const dx = b.x - a.x;
        const dy = b.y - a.y;
        const dist = Math.sqrt(dx * dx + dy * dy) || 1;
        const force = 2000 / (dist * dist);
        const fx = (dx / dist) * force;
        const fy = (dy / dist) * force;

        a.vx -= fx;
        a.vy -= fy;
      }
    }

    // Center gravity
    for (const node of this._nodes) {
      const p = positions[node.id];
      if (!p) continue;
      p.vx += (cx - p.x) * 0.001;
      p.vy += (cy - p.y) * 0.001;
    }

    // Apply velocities with damping
    for (const node of this._nodes) {
      const p = positions[node.id];
      if (!p) continue;
      p.vx *= 0.9;
      p.vy *= 0.9;
      p.x += p.vx * dt * 60;
      p.y += p.vy * dt * 60;
    }
  },

  _draw() {
    const ctx = this._ctx;
    const w = this._width;
    const h = this._height;

    ctx.save();
    ctx.clearRect(0, 0, w, h);

    // Apply transform (pan + zoom)
    ctx.translate(this._offsetX, this._offsetY);
    ctx.scale(this._zoom, this._zoom);

    // Draw edges
    for (const edge of this._edges) {
      const a = this._nodePositions[edge.source];
      const b = this._nodePositions[edge.target];
      if (!a || !b) continue;

      ctx.beginPath();
      ctx.moveTo(a.x, a.y);
      ctx.lineTo(b.x, b.y);
      ctx.strokeStyle = edge.relation === "wikilink" ? "var(--accent-color, #2563eb)" : "var(--text-muted, #888)";
      ctx.lineWidth = edge.relation === "wikilink" ? 2 : 1;
      ctx.setLineDash(edge.relation === "wikilink" ? [4, 4] : []);
      ctx.stroke();
    }
    ctx.setLineDash([]);

    // Draw nodes
    for (const node of this._nodes) {
      const p = this._nodePositions[node.id];
      if (!p) continue;

      const r = Math.max(5, Math.min(20, 6 + Math.sqrt(node.size || 100) / 100));

      // Node circle
      ctx.beginPath();
      ctx.arc(p.x, p.y, r, 0, Math.PI * 2);

      switch (node.type) {
        case "directory":
          ctx.fillStyle = "#5b9bd5";
          break;
        case "file":
          ctx.fillStyle = (node.path || "").endsWith(".md") ? "#70ad47" : "#c0c0c0";
          break;
        default:
          ctx.fillStyle = "#ffc000";
          break;
      }
      ctx.fill();
      ctx.strokeStyle = "var(--bg-primary, #1e1e1e)";
      ctx.lineWidth = 1.5;
      ctx.stroke();

      // Node label
      const label = node.name.length > 20 ? node.name.slice(0, 18) + "..." : node.name;
      ctx.font = `${11 / this._zoom}px -apple-system, sans-serif`;
      ctx.fillStyle = "var(--text-primary, #ddd)";
      ctx.textAlign = "center";
      ctx.fillText(label, p.x, p.y + r + 12 / this._zoom);
    }

    ctx.restore();
  },

  _getNodeAt(screenX, screenY) {
    const x = (screenX - this._offsetX) / this._zoom;
    const y = (screenY - this._offsetY) / this._zoom;

    for (const node of this._nodes) {
      const p = this._nodePositions[node.id];
      if (!p) continue;
      const r = Math.max(5, Math.min(20, 6 + Math.sqrt(node.size || 100) / 100));
      const dx = x - p.x;
      const dy = y - p.y;
      if (dx * dx + dy * dy <= r * r + 100) {
        return { node, pos: p };
      }
    }
    return null;
  },

  _onMouseDown(e) {
    const rect = this._canvas.getBoundingClientRect();
    const mx = e.clientX - rect.left;
    const my = e.clientY - rect.top;

    const hit = this._getNodeAt(mx, my);
    if (hit) {
      this._dragging = true;
      this._dragNode = hit;
      this._canvas.style.cursor = "grabbing";
    } else {
      this._panning = true;
      this._panStartX = e.clientX - this._offsetX;
      this._panStartY = e.clientY - this._offsetY;
      this._canvas.style.cursor = "grabbing";
    }
  },

  _onMouseMove(e) {
    const rect = this._canvas.getBoundingClientRect();
    const mx = e.clientX - rect.left;
    const my = e.clientY - rect.top;

    if (this._dragging && this._dragNode) {
      this._dragNode.pos.x = (mx - this._offsetX) / this._zoom;
      this._dragNode.pos.y = (my - this._offsetY) / this._zoom;
      this._dragNode.pos.vx = 0;
      this._dragNode.pos.vy = 0;
    } else if (this._panning) {
      this._offsetX = e.clientX - this._panStartX;
      this._offsetY = e.clientY - this._panStartY;
    } else {
      const hit = this._getNodeAt(mx, my);
      this._canvas.style.cursor = hit ? "pointer" : "grab";
      this._canvas.title = hit ? `Ouvrir: ${hit.node.path || hit.node.name}` : "";
    }
  },

  _onMouseUp(e) {
    if (this._dragging && this._dragNode) {
      // Check if it was a click (not a drag)
      const rect = this._canvas.getBoundingClientRect();
      const node = this._dragNode.node;
      this._dragging = false;
      this._dragNode = null;
      this._canvas.style.cursor = "grab";

      // If it's a file, open it on click
      if (node.type === "file") {
        this.close();
        openFile(this._vault, node.path);
      } else if (node.type === "directory" || node.type === "vault") {
        // Expand into this directory
        this.close();
        this.open(this._vault, node.path, node.type);
      }
    }
    this._panning = false;
  },

  _onWheel(e) {
    e.preventDefault();
    const rect = this._canvas.getBoundingClientRect();
    const mx = e.clientX - rect.left;
    const my = e.clientY - rect.top;

    const zoomFactor = e.deltaY < 0 ? 1.1 : 0.9;
    const newZoom = Math.max(0.2, Math.min(3, this._zoom * zoomFactor));

    this._offsetX = mx - (mx - this._offsetX) * (newZoom / this._zoom);
    this._offsetY = my - (my - this._offsetY) * (newZoom / this._zoom);
    this._zoom = newZoom;
  },

  _onResize() {
    if (!this._canvas || !this._nodes.length) return;
    const w = this._canvas.parentElement.clientWidth;
    const h = this._canvas.parentElement.clientHeight;
    this._canvas.width = w * devicePixelRatio;
    this._canvas.height = h * devicePixelRatio;
    this._canvas.style.width = w + "px";
    this._canvas.style.height = h + "px";
    this._width = w;
    this._height = h;
    this._ctx.setTransform(1, 0, 0, 1, 0, 0);
    this._ctx.scale(devicePixelRatio, devicePixelRatio);
  },
};

// ---------------------------------------------------------------------------
// Init graph view event listeners after DOM ready
// ---------------------------------------------------------------------------
export function initGraphView() {
  const closeBtn = document.getElementById("graph-close");
  const zoomIn = document.getElementById("graph-zoom-in");
  const zoomOut = document.getElementById("graph-zoom-out");
  const reset = document.getElementById("graph-reset");
  const modal = document.getElementById("graph-modal");
  const canvas = document.getElementById("graph-canvas");

  if (closeBtn) closeBtn.addEventListener("click", () => GraphViewManager.close());
  if (modal) modal.addEventListener("click", (e) => { if (e.target === modal) GraphViewManager.close(); });
  if (zoomIn) zoomIn.addEventListener("click", () => { GraphViewManager._zoom = Math.min(3, GraphViewManager._zoom * 1.2); });
  if (zoomOut) zoomOut.addEventListener("click", () => { GraphViewManager._zoom = Math.max(0.2, GraphViewManager._zoom * 0.8); });
  if (reset) reset.addEventListener("click", () => {
    GraphViewManager._offsetX = 0;
    GraphViewManager._offsetY = 0;
    GraphViewManager._zoom = 1;
  });

  if (canvas) {
    canvas.addEventListener("mousedown", (e) => GraphViewManager._onMouseDown(e));
    canvas.addEventListener("mousemove", (e) => GraphViewManager._onMouseMove(e));
    canvas.addEventListener("mouseup", (e) => GraphViewManager._onMouseUp(e));
    canvas.addEventListener("mouseleave", () => {
      GraphViewManager._dragging = false;
      GraphViewManager._dragNode = null;
      GraphViewManager._panning = false;
      canvas.style.cursor = "grab";
    });
    canvas.addEventListener("wheel", (e) => GraphViewManager._onWheel(e), { passive: false });
    window.addEventListener("resize", () => GraphViewManager._onResize());
  }

  document.addEventListener("keydown", (e) => {
    if (modal && modal.classList.contains("active") && e.key === "Escape") {
      GraphViewManager.close();
    }
  });
}