/**
 * Canvas graph: example graph and initial graph from storage.
 * Used by useCanvasGraph and CanvasPage (e.g. Load example).
 */

import type { AppNode, AppEdge } from '@/lib/graph/nodeTypes'
import { DEFAULT_NODE_STYLE } from '@/lib/graph/flowUtils'
import { loadGraphFromStorage } from '@/app/pleroma/projectGraphStorage'

/** Ensure each edge has data.targetType from the target node (for labels without depending on nodes in edgesForFlow). */
export function backfillEdgeTargetTypes(
  nodes: AppNode[],
  edges: AppEdge[]
): AppEdge[] {
  const typeById = new Map(nodes.map((n) => [n.id, n.type ?? '']))
  return edges.map((e) => {
    const targetType = typeById.get(e.target) ?? (e.data as Record<string, unknown>)?.targetType ?? ''
    const data = typeof e.data === 'object' && e.data !== null ? (e.data as Record<string, unknown>) : {}
    if (data.targetType === targetType) return e
    return { ...e, data: { ...data, targetType } }
  })
}

const NODE_GAP = 150

const EXAMPLE_NODES: AppNode[] = [
  {
    id: 'var_001',
    position: { x: 50, y: 100 },
    data: { value: 'Zoe', valueType: 'string' as const },
    type: 'variable',
    style: DEFAULT_NODE_STYLE.variable,
  },
  {
    id: 'cfg_001',
    position: { x: 50 + DEFAULT_NODE_STYLE.variable.width + NODE_GAP, y: 50 },
    data: {
      plantuml: '@startuml\nactor User\nparticipant "{{ var_001 }}" as R\nUser -> R : loves\n@enduml\n',
      title: 'config-cfg_001',
    },
    type: 'config',
    style: DEFAULT_NODE_STYLE.config,
  },
  {
    id: 'rnd_001',
    position: {
      x: 50 + DEFAULT_NODE_STYLE.variable.width + NODE_GAP + DEFAULT_NODE_STYLE.config.width + NODE_GAP,
      y: 50,
    },
    data: {},
    type: 'render',
    style: DEFAULT_NODE_STYLE.render,
  },
]

const EXAMPLE_EDGES: AppEdge[] = [
  { id: 'e-var_001-cfg_001', source: 'var_001', target: 'cfg_001', type: 'animated' },
  { id: 'e-cfg_001-rnd_001', source: 'cfg_001', target: 'rnd_001', type: 'animated' },
]

export function getExampleGraph(): { nodes: AppNode[]; edges: AppEdge[] } {
  const nodes = EXAMPLE_NODES.map((n) => ({
    ...n,
    data: n.data && typeof n.data === 'object' ? { ...(n.data as object) } : n.data,
  }))
  const edges = backfillEdgeTargetTypes(
    nodes,
    EXAMPLE_EDGES.map((e) => ({ ...e }))
  )
  return { nodes, edges }
}

export function getInitialGraph(projectId: string | undefined): { nodes: AppNode[]; edges: AppEdge[] } {
  if (projectId) {
    const stored = loadGraphFromStorage(projectId)
    if (stored && (stored.nodes.length > 0 || stored.edges.length > 0)) {
      const nodes = stored.nodes as AppNode[]
      const edges = backfillEdgeTargetTypes(nodes, stored.edges as AppEdge[])
      return { nodes, edges }
    }
    return { nodes: [], edges: [] }
  }
  return getExampleGraph()
}