import { useEffect, useRef, useState, useCallback, useContext } from 'react'
import ReactFlow, { addEdge, Controls, Background, useNodesState, useEdgesState } from 'reactflow'
import 'reactflow/dist/style.css'

import { useDispatch, useSelector } from 'react-redux'
import { useNavigate, useLocation } from 'react-router-dom'
import { usePrompt } from '../../utils/usePrompt'
import {
    REMOVE_DIRTY,
    SET_DIRTY,
    SET_CHATFLOW,
    enqueueSnackbar as enqueueSnackbarAction,
    closeSnackbar as closeSnackbarAction
} from 'store/actions'

// material-ui
import { Toolbar, Box, AppBar, Button } from '@mui/material'
import { useTheme } from '@mui/material/styles'

// project imports
import CanvasNode from './CanvasNode'
import ButtonEdge from './ButtonEdge'
import CanvasHeader from './CanvasHeader'
import AddNodes from './AddNodes'
import ConfirmDialog from 'ui-component/dialog/ConfirmDialog'
import { ChatPopUp } from 'views/chatmessage/ChatPopUp'
import { flowContext } from 'store/context/ReactFlowContext'

// API
import nodesApi from 'api/nodes'
import chatflowsApi from 'api/chatflows'

// Hooks
import useApi from 'hooks/useApi'
import useConfirm from 'hooks/useConfirm'

// icons
import { IconX } from '@tabler/icons'

// utils
import { getUniqueNodeId, initNode, getEdgeLabelName, rearrangeToolsOrdering } from 'utils/genericHelper'
import useNotifier from 'utils/useNotifier'

const nodeTypes = { customNode: CanvasNode }
const edgeTypes = { buttonedge: ButtonEdge }

// ==============================|| CANVAS ||============================== //

const Canvas = () => {
    const theme = useTheme()
    const navigate = useNavigate()

    const { state } = useLocation()
    const templateFlowData = state ? state.templateFlowData : ''

    const URLpath = document.location.pathname.toString().split('/')
    const chatflowId = URLpath[URLpath.length - 1] === 'canvas' ? '' : URLpath[URLpath.length - 1]

    const { confirm } = useConfirm()

    const dispatch = useDispatch()
    const canvas = useSelector((state) => state.canvas)
    const [canvasDataStore, setCanvasDataStore] = useState(canvas)
    const [chatflow, setChatflow] = useState(null)

    const { reactFlowInstance, setReactFlowInstance } = useContext(flowContext)

    // ==============================|| Snackbar ||============================== //

    useNotifier()
    const enqueueSnackbar = (...args) => dispatch(enqueueSnackbarAction(...args))
    const closeSnackbar = (...args) => dispatch(closeSnackbarAction(...args))

    // ==============================|| ReactFlow ||============================== //

    const [nodes, setNodes, onNodesChange] = useNodesState()
    const [edges, setEdges, onEdgesChange] = useEdgesState()

    const [selectedNode, setSelectedNode] = useState(null)

    const reactFlowWrapper = useRef(null)

    // ==============================|| Chatflow API ||============================== //

    const getNodesApi = useApi(nodesApi.getAllNodes)
    const createNewChatflowApi = useApi(chatflowsApi.createNewChatflow)
    const testChatflowApi = useApi(chatflowsApi.testChatflow)
    const updateChatflowApi = useApi(chatflowsApi.updateChatflow)
    const getSpecificChatflowApi = useApi(chatflowsApi.getSpecificChatflow)

    // ==============================|| Events & Actions ||============================== //

    const onConnect = (params) => {
        const newEdge = {
            ...params,
            type: 'buttonedge',
            id: `${params.source}-${params.sourceHandle}-${params.target}-${params.targetHandle}`,
            data: { label: getEdgeLabelName(params.sourceHandle) }
        }

        const targetNodeId = params.targetHandle.split('-')[0]
        const sourceNodeId = params.sourceHandle.split('-')[0]
        const targetInput = params.targetHandle.split('-')[2]

        setNodes((nds) =>
            nds.map((node) => {
                if (node.id === targetNodeId) {
                    setTimeout(() => setDirty(), 0)
                    let value
                    const inputAnchor = node.data.inputAnchors.find((ancr) => ancr.name === targetInput)
                    const inputParam = node.data.inputParams.find((param) => param.name === targetInput)

                    if (inputAnchor && inputAnchor.list) {
                        const newValues = node.data.inputs[targetInput] || []
                        if (targetInput === 'tools') {
                            rearrangeToolsOrdering(newValues, sourceNodeId)
                        } else {
                            newValues.push(`{{${sourceNodeId}.data.instance}}`)
                        }
                        value = newValues
                    } else if (inputParam && inputParam.acceptVariable) {
                        value = node.data.inputs[targetInput] || ''
                    } else {
                        value = `{{${sourceNodeId}.data.instance}}`
                    }
                    node.data = {
                        ...node.data,
                        inputs: {
                            ...node.data.inputs,
                            [targetInput]: value
                        }
                    }
                }
                return node
            })
        )

        setEdges((eds) => addEdge(newEdge, eds))
    }

    const handleLoadFlow = (file) => {
        try {
            const flowData = JSON.parse(file)
            const nodes = flowData.nodes || []

            setNodes(nodes)
            setEdges(flowData.edges || [])
            setDirty()
        } catch (e) {
            console.error(e)
        }
    }

    const handleDeleteFlow = async () => {
        const confirmPayload = {
            title: `Delete`,
            description: `Delete chatflow ${chatflow.name}?`,
            confirmButtonName: 'Delete',
            cancelButtonName: 'Cancel'
        }
        const isConfirmed = await confirm(confirmPayload)

        if (isConfirmed) {
            try {
                await chatflowsApi.deleteChatflow(chatflow.id)
                navigate(-1)
            } catch (error) {
                const errorData = error.response.data || `${error.response.status}: ${error.response.statusText}`
                enqueueSnackbar({
                    message: errorData,
                    options: {
                        key: new Date().getTime() + Math.random(),
                        variant: 'error',
                        persist: true,
                        action: (key) => (
                            <Button style={{ color: 'white' }} onClick={() => closeSnackbar(key)}>
                                <IconX />
                            </Button>
                        )
                    }
                })
            }
        }
    }

    const handleSaveFlow = (chatflowName) => {
        if (reactFlowInstance) {
            setNodes((nds) =>
                nds.map((node) => {
                    node.data = {
                        ...node.data,
                        selected: false
                    }
                    return node
                })
            )

            const rfInstanceObject = reactFlowInstance.toObject()
            const flowData = JSON.stringify(rfInstanceObject)

            if (!chatflow.id) {
                const newChatflowBody = {
                    name: chatflowName,
                    deployed: false,
                    flowData
                }
                createNewChatflowApi.request(newChatflowBody)
            } else {
                const updateBody = {
                    name: chatflowName,
                    flowData
                }
                updateChatflowApi.request(chatflow.id, updateBody)
            }
        }
    }

    // eslint-disable-next-line
    const onNodeClick = useCallback((event, clickedNode) => {
        setSelectedNode(clickedNode)
        setNodes((nds) =>
            nds.map((node) => {
                if (node.id === clickedNode.id) {
                    node.data = {
                        ...node.data,
                        selected: true
                    }
                } else {
                    node.data = {
                        ...node.data,
                        selected: false
                    }
                }

                return node
            })
        )
    })

    const onDragOver = useCallback((event) => {
        event.preventDefault()
        event.dataTransfer.dropEffect = 'move'
    }, [])

    const onDrop = useCallback(
        (event) => {
            event.preventDefault()
            const reactFlowBounds = reactFlowWrapper.current.getBoundingClientRect()
            let nodeData = event.dataTransfer.getData('application/reactflow')

            // check if the dropped element is valid
            if (typeof nodeData === 'undefined' || !nodeData) {
                return
            }

            nodeData = JSON.parse(nodeData)

            const position = reactFlowInstance.project({
                x: event.clientX - reactFlowBounds.left - 100,
                y: event.clientY - reactFlowBounds.top - 50
            })

            const newNodeId = getUniqueNodeId(nodeData, reactFlowInstance.getNodes())

            const newNode = {
                id: newNodeId,
                position,
                type: 'customNode',
                data: initNode(nodeData, newNodeId)
            }

            setSelectedNode(newNode)
            setNodes((nds) =>
                nds.concat(newNode).map((node) => {
                    if (node.id === newNode.id) {
                        node.data = {
                            ...node.data,
                            selected: true
                        }
                    } else {
                        node.data = {
                            ...node.data,
                            selected: false
                        }
                    }

                    return node
                })
            )
            setTimeout(() => setDirty(), 0)
        },

        // eslint-disable-next-line
        [reactFlowInstance]
    )

    const saveChatflowSuccess = () => {
        dispatch({ type: REMOVE_DIRTY })
        enqueueSnackbar({
            message: 'Chatflow saved',
            options: {
                key: new Date().getTime() + Math.random(),
                variant: 'success',
                action: (key) => (
                    <Button style={{ color: 'white' }} onClick={() => closeSnackbar(key)}>
                        <IconX />
                    </Button>
                )
            }
        })
    }

    const errorFailed = (message) => {
        enqueueSnackbar({
            message,
            options: {
                key: new Date().getTime() + Math.random(),
                variant: 'error',
                persist: true,
                action: (key) => (
                    <Button style={{ color: 'white' }} onClick={() => closeSnackbar(key)}>
                        <IconX />
                    </Button>
                )
            }
        })
    }

    const setDirty = () => {
        dispatch({ type: SET_DIRTY })
    }

    // ==============================|| useEffect ||============================== //

    // Get specific chatflow successful
    useEffect(() => {
        if (getSpecificChatflowApi.data) {
            const chatflow = getSpecificChatflowApi.data
            const initialFlow = chatflow.flowData ? JSON.parse(chatflow.flowData) : []
            setNodes(initialFlow.nodes || [])
            setEdges(initialFlow.edges || [])
            dispatch({ type: SET_CHATFLOW, chatflow })
        } else if (getSpecificChatflowApi.error) {
            const error = getSpecificChatflowApi.error
            const errorData = error.response.data || `${error.response.status}: ${error.response.statusText}`
            errorFailed(`Failed to retrieve chatflow: ${errorData}`)
        }

        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [getSpecificChatflowApi.data, getSpecificChatflowApi.error])

    // Create new chatflow successful
    useEffect(() => {
        if (createNewChatflowApi.data) {
            const chatflow = createNewChatflowApi.data
            dispatch({ type: SET_CHATFLOW, chatflow })
            saveChatflowSuccess()
            window.history.replaceState(null, null, `/canvas/${chatflow.id}`)
        } else if (createNewChatflowApi.error) {
            const error = createNewChatflowApi.error
            const errorData = error.response.data || `${error.response.status}: ${error.response.statusText}`
            errorFailed(`Failed to save chatflow: ${errorData}`)
        }

        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [createNewChatflowApi.data, createNewChatflowApi.error])

    // Update chatflow successful
    useEffect(() => {
        if (updateChatflowApi.data) {
            dispatch({ type: SET_CHATFLOW, chatflow: updateChatflowApi.data })
            saveChatflowSuccess()
        } else if (updateChatflowApi.error) {
            const error = updateChatflowApi.error
            const errorData = error.response.data || `${error.response.status}: ${error.response.statusText}`
            errorFailed(`Failed to save chatflow: ${errorData}`)
        }

        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [updateChatflowApi.data, updateChatflowApi.error])

    // Test chatflow failed
    useEffect(() => {
        if (testChatflowApi.error) {
            enqueueSnackbar({
                message: 'Test chatflow failed',
                options: {
                    key: new Date().getTime() + Math.random(),
                    variant: 'error',
                    persist: true,
                    action: (key) => (
                        <Button style={{ color: 'white' }} onClick={() => closeSnackbar(key)}>
                            <IconX />
                        </Button>
                    )
                }
            })
        }

        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [testChatflowApi.error])

    useEffect(() => setChatflow(canvasDataStore.chatflow), [canvasDataStore.chatflow])

    // Initialization
    useEffect(() => {
        if (chatflowId) {
            getSpecificChatflowApi.request(chatflowId)
        } else {
            if (localStorage.getItem('duplicatedFlowData')) {
                handleLoadFlow(localStorage.getItem('duplicatedFlowData'))
                setTimeout(() => localStorage.removeItem('duplicatedFlowData'), 0)
            } else {
                setNodes([])
                setEdges([])
            }
            dispatch({
                type: SET_CHATFLOW,
                chatflow: {
                    name: 'Untitled chatflow'
                }
            })
        }

        getNodesApi.request()

        // Clear dirty state before leaving and remove any ongoing test triggers and webhooks
        return () => {
            setTimeout(() => dispatch({ type: REMOVE_DIRTY }), 0)
        }

        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [])

    useEffect(() => {
        setCanvasDataStore(canvas)
    }, [canvas])

    useEffect(() => {
        function handlePaste(e) {
            const pasteData = e.clipboardData.getData('text')
            //TODO: prevent paste event when input focused, temporary fix: catch chatflow syntax
            if (pasteData.includes('{"nodes":[') && pasteData.includes('],"edges":[')) {
                handleLoadFlow(pasteData)
            }
        }

        window.addEventListener('paste', handlePaste)

        return () => {
            window.removeEventListener('paste', handlePaste)
        }

        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [])

    useEffect(() => {
        if (templateFlowData && templateFlowData.includes('"nodes":[') && templateFlowData.includes('],"edges":[')) {
            handleLoadFlow(templateFlowData)
        }

        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [templateFlowData])

    usePrompt('You have unsaved changes! Do you want to navigate away?', canvasDataStore.isDirty)

    return (
        <>
            <Box>
                <AppBar
                    enableColorOnDark
                    position='fixed'
                    color='inherit'
                    elevation={1}
                    sx={{
                        bgcolor: theme.palette.background.default
                    }}
                >
                    <Toolbar>
                        <CanvasHeader
                            chatflow={chatflow}
                            handleSaveFlow={handleSaveFlow}
                            handleDeleteFlow={handleDeleteFlow}
                            handleLoadFlow={handleLoadFlow}
                        />
                    </Toolbar>
                </AppBar>
                <Box sx={{ pt: '70px', height: '100vh', width: '100%' }}>
                    <div className='reactflow-parent-wrapper'>
                        <div className='reactflow-wrapper' ref={reactFlowWrapper}>
                            <ReactFlow
                                nodes={nodes}
                                edges={edges}
                                onNodesChange={onNodesChange}
                                onNodeClick={onNodeClick}
                                onEdgesChange={onEdgesChange}
                                onDrop={onDrop}
                                onDragOver={onDragOver}
                                onNodeDragStop={setDirty}
                                nodeTypes={nodeTypes}
                                edgeTypes={edgeTypes}
                                onConnect={onConnect}
                                onInit={setReactFlowInstance}
                                fitView
                                minZoom={0.1}
                            >
                                <Controls
                                    style={{
                                        display: 'flex',
                                        flexDirection: 'row',
                                        left: '50%',
                                        transform: 'translate(-50%, -50%)'
                                    }}
                                />
                                <Background color='#aaa' gap={16} />
                                <AddNodes nodesData={getNodesApi.data} node={selectedNode} />
                                <ChatPopUp chatflowid={chatflowId} />
                            </ReactFlow>
                        </div>
                    </div>
                </Box>
                <ConfirmDialog />
            </Box>
        </>
    )
}

export default Canvas