import React, { useCallback, useContext, useEffect, useRef, useState } from 'react'
import { GraphContext, FlowUIContext } from '@/lib/graph/flowContext'
import type { AppNode } from '@/lib/graph/nodeTypes'
import { replaceNodeIdInGraph } from '@/lib/graph/flowUtils'

type Props = {
    nodeId: string
    displayTitle: string
}

export function NodeHeaderTitle({ nodeId, displayTitle }: Props) {
    const graphCtx = useContext(GraphContext)
    const uiCtx = useContext(FlowUIContext)
    const nodes = graphCtx?.nodes ?? []
    const setNodes = graphCtx?.setNodes
    const edges = graphCtx?.edges ?? []
    const setEdges = graphCtx?.setEdges
    const renamingNodeId = uiCtx?.renamingNodeId ?? null
    const setRenamingNodeId = uiCtx?.setRenamingNodeId

    const [inputValue, setInputValue] = useState(nodeId)
    const inputRef = useRef<HTMLInputElement>(null)

    const isRenaming = renamingNodeId === nodeId

    useEffect(() => {
        if (isRenaming) {
            setInputValue(nodeId)
            inputRef.current?.focus()
            inputRef.current?.select()
        }
    }, [isRenaming, nodeId])

    const applyRename = useCallback(() => {
        if (!setNodes || !setEdges || !setRenamingNodeId) return
        const newId = inputValue.trim()
        if (!newId || newId === nodeId) {
            setRenamingNodeId(null)
            return
        }
        const existingIds = nodes.map((n: any) => n.id)
        if (existingIds.includes(newId)) {
            return
        }
        const { nodes: nextNodes, edges: nextEdges } = replaceNodeIdInGraph(nodes, edges, nodeId, newId)
        setNodes(nextNodes as AppNode[])
        setEdges(nextEdges)
        setRenamingNodeId(null)
    }, [nodeId, inputValue, nodes, edges, setNodes, setEdges, setRenamingNodeId])

    const cancelRename = useCallback(() => {
        setRenamingNodeId?.(null)
    }, [setRenamingNodeId])

    const handleKeyDown = useCallback(
        (e: React.KeyboardEvent<HTMLInputElement>) => {
            if (e.key === 'Enter') {
                e.preventDefault()
                applyRename()
            } else if (e.key === 'Escape') {
                e.preventDefault()
                cancelRename()
            }
        },
        [applyRename, cancelRename]
    )

    if (!isRenaming) {
        return <>{displayTitle}</>
    }

    return (
        <input
            ref={inputRef}
            type="text"
            value={inputValue}
            onChange={(e) => setInputValue(e.target.value)}
            onKeyDown={handleKeyDown}
            onBlur={cancelRename}
            className="nodrag nopan flex-1 min-w-0 rounded border border-input bg-background px-1.5 py-0 text-sm font-semibold outline-none focus:ring-1 focus:ring-ring"
            data-slot="base-node-title"
        />
    )
}