/**
 * runs the resolve → render pipeline, manages streaming/cache,
 * and exposes derived state for the dumb UI. See lib/graph/rendering.ts for the
 * pipeline interface.
 */

import { useCallback, useDeferredValue, useEffect, useMemo, useRef, useState } from 'react'
import { useAbstractNode } from '@/lib/graph/abstractNode'
import { useSyncConnectionStatus } from '@/lib/graph/nodeLifecycle'
import { useCanvasStore, dispatchCanvasCommand } from '@/app/canvas/canvasStore'
import { usePlatform } from '@/app/kosmos/KosmosContext'
import { getDefaultDataForType, getNextNodeId } from '@/lib/graph/flowUtils'
import { getDefaultStyle } from '@/lib/graph/nodeRegistry'
import {
    getConfigContent,
    getConfigType,
    getConfigTypeId,
    getSourceRenderingLogic,
    parseThinkSections,
    processSvgDisplay,
    stripTemplateSyntax,
} from '@/lib/graph/rendering'
import { buildSourceSignatures, type NodeLike, type EdgeLike } from '@/lib/graph/renderingSignatures'
import { getNodeDisplayStatus, type NodeDisplayStatus } from '@/lib/graph/state'
import type { ConfigTypeId, SourceRenderingLogicContext } from '@/lib/graph/rendering'

export type RenderingNodeData = {
    viewportWidth?: number
    viewportHeight?: number
    updateMode?: 'auto' | 'manual'
    runTrigger?: number
    lastRunSourceSignature?: string
    cachedRenderedContent?: string
    cachedResolvedContent?: string
    cachedReasoningContent?: string
}

const DEFAULT_VIEWPORT_WIDTH = 1200
const DEFAULT_VIEWPORT_HEIGHT = 800
const RENDER_DEBOUNCE_MS = 250

/** Lifecycle state to pass to useSyncConnectionStatus so edge status (updating/error) stays in sync. */
export type RenderingNodeLifecycle = {
    updating: boolean
    error: boolean
}

export type RenderingNodeState = {
    /** For NodeStatusIndicator and empty/error UI. Derived from loading, error, renderedContent. */
    displayStatus: NodeDisplayStatus
    /** Pass to useSyncConnectionStatus so edges show correct status (blue/yellow/red). */
    lifecycle: RenderingNodeLifecycle

    // Connection & run control
    incomingIds: string[]
    effectiveUpdateMode: 'auto' | 'manual'
    runTrigger: number
    hasPendingInputs: boolean
    loading: boolean
    error: null | { kind: string; message: string }
    incrementRunTrigger: () => void
    setUpdateMode: (mode: 'auto' | 'manual') => void
    setRetryCount: (fn: (c: number) => number) => void

    // Content (resolved = before render, rendered = after render)
    renderedContent: string | null
    resolvedContent: string | null
    streamingMarkdown: string | null
    streamingPreviewHtml: string
    reasoningContent: string
    reasoningHtml: string

    // Display type (no config/agent types exposed)
    outputType: 'html' | 'image'
    outputLabel: string
    rawLanguage: ConfigTypeId
    isSvgOutput: boolean

    // Derived for UI
    renderedThinkSplit: { main: string; think: string }
    streamingThinkSplit: { main: string; think: string }
    rawDisplayContent: string
    displayContent: string | null

    // Viewport
    viewportWidth: number
    viewportHeight: number

    // Empty state (source-type-specific action stays in hook)
    emptyStateAction: null | { label: string; onClick: () => void }

    // Optional custom error UI from source node data
    sourceData: Record<string, unknown>

    /** Source node type id (e.g. 'config', 'agent') for Output menu from descriptor. */
    sourceNodeType: string | null
}

export function useRenderingNodeState(
    id: string,
    data: RenderingNodeData | undefined
): RenderingNodeState {
    const {
        nodes: contextNodes,
        edges: contextEdges,
        setNodes,
        setEdges,
        sourceIds: incomingIds,
        updateData,
    } = useAbstractNode<RenderingNodeData>(id, data ?? {})

    // Subscribe to store graph so we re-render when any node/edge changes (e.g. ascendant data).
    // Context only exposes a ref, so we wouldn't re-render when another node updates otherwise.
    const storeNodes = useCanvasStore((s) => s.graph.nodes)
    const storeEdges = useCanvasStore((s) => s.graph.edges)
    const nodes = storeNodes.length > 0 ? storeNodes : contextNodes
    const edges = storeEdges.length > 0 ? storeEdges : contextEdges

    const nodesEdgesRef = useRef({ nodes, edges })
    nodesEdgesRef.current = { nodes, edges }

    const { aiConnection } = usePlatform()

    const viewportWidth = data?.viewportWidth ?? DEFAULT_VIEWPORT_WIDTH
    const viewportHeight = data?.viewportHeight ?? DEFAULT_VIEWPORT_HEIGHT

    const deferredNodes = useDeferredValue(nodes)
    const deferredEdges = useDeferredValue(edges)
    const srcId = incomingIds.length > 0 ? incomingIds[0] : null
    const srcNode = useMemo(
        () => (srcId ? nodes.find((n: { id: string }) => n.id === srcId) : null),
        [nodes, srcId]
    )

    const sourceLogic = useMemo(
        () => (srcNode?.type ? getSourceRenderingLogic(srcNode.type as string) : null),
        [srcNode?.type]
    )
    const effectiveUpdateMode = (data?.updateMode ?? sourceLogic?.defaultUpdateMode ?? 'auto') as 'auto' | 'manual'
    const runTrigger = data?.runTrigger ?? 0
    const isAgentSource = srcNode?.type === 'agent'
    const agentOutputMarkdown = isAgentSource
        ? ((srcNode?.data as { outputMarkdown?: string })?.outputMarkdown ?? '')
        : ''
    const configTypeId: ConfigTypeId =
        srcNode?.type === 'config'
            ? getConfigTypeId((srcNode?.data ?? undefined) as Record<string, unknown> | undefined)
            : isAgentSource
              ? 'markdown'
              : 'plantuml'
    const configType = getConfigType(configTypeId)
    const outputType = configType.outputType
    const sourceContent =
        srcNode?.type === 'config'
            ? getConfigContent((srcNode?.data ?? undefined) as Record<string, unknown> | undefined)
            : isAgentSource
              ? agentOutputMarkdown
              : ''

    const signatures = useMemo(
        () => buildSourceSignatures(deferredNodes as NodeLike[], deferredEdges as EdgeLike[], id, incomingIds),
        [deferredNodes, deferredEdges, id, incomingIds]
    )
    const {
        connectedNodeIds,
        configSignature,
        edgesSignature,
        variablesSignature,
        functionsSignature,
        dataSignature,
        sourceSignature,
    } = signatures

    const lastRunSourceSignature = data?.lastRunSourceSignature

    const [renderedContent, setRenderedContent] = useState<string | null>(
        () => (data?.cachedRenderedContent as string | undefined) ?? null
    )
    const [resolvedContent, setResolvedContent] = useState<string | null>(
        () => (data?.cachedResolvedContent as string | undefined) ?? null
    )
    const [error, setError] = useState<null | { kind: string; message: string }>(null)
    const [loading, setLoading] = useState(false)
    const [streamingMarkdown, setStreamingMarkdown] = useState<string | null>(null)
    const [streamingPreviewHtml, setStreamingPreviewHtml] = useState<string>('')
    const [reasoningContent, setReasoningContent] = useState<string>(
        () => (data?.cachedReasoningContent as string | undefined) ?? ''
    )
    const [reasoningHtml, setReasoningHtml] = useState<string>('')
    const [retryCount, setRetryCountState] = useState(0)

    const runIdRef = useRef(0)
    const loadingStartedAtRef = useRef<number | null>(null)
    const minLoadingTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null)
    const lastManualRunTriggerRef = useRef(0)
    const manualRunTriggerSyncedRef = useRef(false)

    const updateDataRef = useRef(updateData)
    updateDataRef.current = updateData
    const setNodesRef = useRef(setNodes)
    setNodesRef.current = setNodes
    const aiConnectionRef = useRef(aiConnection)
    aiConnectionRef.current = aiConnection
    const hasPendingInputs =
        effectiveUpdateMode === 'manual' &&
        !loading &&
        incomingIds.length > 0 &&
        sourceSignature !== lastRunSourceSignature

    const lifecycle = useMemo<RenderingNodeLifecycle>(
        () => ({ updating: loading, error: error != null }),
        [loading, error]
    )
    useSyncConnectionStatus(id, lifecycle)

    useEffect(() => {
        if (incomingIds.length === 0) {
            setRenderedContent(null)
            setResolvedContent(null)
            setError(null)
            setLoading(false)
            return
        }
        if (!srcId || !srcNode) {
            setRenderedContent(null)
            setResolvedContent(null)
            setError(null)
            setLoading(false)
            return
        }
        const logic = getSourceRenderingLogic(srcNode.type as string)
        if (!logic) {
            setRenderedContent(null)
            setResolvedContent(null)
            setError({ kind: 'render', message: `Unsupported source type: ${srcNode.type}` })
            setLoading(false)
            return
        }
        if (effectiveUpdateMode === 'manual') {
            if (!manualRunTriggerSyncedRef.current) {
                lastManualRunTriggerRef.current = runTrigger
                manualRunTriggerSyncedRef.current = true
                return
            }
            if (runTrigger === 0) {
                const hasCachedOutput = Boolean(
                    (data?.cachedRenderedContent ?? data?.cachedResolvedContent) as string | undefined
                )
                if (!hasCachedOutput) {
                    setRenderedContent(null)
                    setResolvedContent(null)
                    setError({ kind: 'no-content', message: 'Click Run to render.' })
                    setLoading(false)
                }
                return
            }
            if (runTrigger === lastManualRunTriggerRef.current) return
            lastManualRunTriggerRef.current = runTrigger
        }

        runIdRef.current += 1
        const thisRunId = runIdRef.current
        const signatureForThisRun = sourceSignature
        const isManualMode = effectiveUpdateMode === 'manual'
        let cancelled = false

        const run = async () => {
            dispatchCanvasCommand({ type: 'path/addTrigger', payload: id })
            loadingStartedAtRef.current = Date.now()
            setLoading(true)
            setError(null)
            setRenderedContent(null)
            setResolvedContent(null)
            setStreamingMarkdown(null)
            setReasoningContent('')
            updateDataRef.current({
                cachedRenderedContent: undefined,
                cachedResolvedContent: undefined,
                cachedReasoningContent: undefined,
            })
            try {
                // Pipeline: 1) Resolve (source) → 2) Render (output type) → 3) Cache
                const { nodes: ctxNodes, edges: ctxEdges } = nodesEdgesRef.current
                const context = {
                    nodes: ctxNodes,
                    edges: ctxEdges,
                    sourceNodeId: srcId,
                    renderNodeId: id,
                    viewportWidth,
                    viewportHeight,
                    setNodes: setNodesRef.current ?? undefined,
                    aiConnection: aiConnectionRef.current,
                    ...(isAgentSource && {
                        onStreamingStart: () => setStreamingMarkdown(''),
                        onStreamingChunk: (chunk: string) =>
                            setStreamingMarkdown((prev) => (prev ?? '') + chunk),
                    }),
                } as SourceRenderingLogicContext
                const { resolved, outputTypeId, reasoning } = await logic.getResolvedContent(context)
                if (thisRunId !== runIdRef.current) return
                setResolvedContent(resolved)
                setReasoningContent(reasoning ?? '')
                const typeRenderer = getConfigType(outputTypeId)
                const renderOptions =
                    outputTypeId === 'wireframe' ? { width: viewportWidth, height: viewportHeight } : undefined
                const htmlOrSvg = await typeRenderer.render(resolved, renderOptions)
                if (thisRunId !== runIdRef.current) return
                setRenderedContent(htmlOrSvg)
                setError(null)
                updateDataRef.current({
                    cachedRenderedContent: htmlOrSvg,
                    cachedResolvedContent: resolved,
                    cachedReasoningContent: reasoning ?? '',
                    ...(isManualMode ? { lastRunSourceSignature: signatureForThisRun } : {}),
                })
            } catch (err: unknown) {
                if (!cancelled && thisRunId === runIdRef.current) {
                    setRenderedContent(null)
                    setReasoningContent('')
                    setError({
                        kind: 'render',
                        message: (err as { message?: string })?.message ?? 'Render error',
                    })
                }
            } finally {
                setStreamingMarkdown(null)
                if (thisRunId === runIdRef.current) {
                    const startedAt = loadingStartedAtRef.current ?? 0
                    const elapsed = Date.now() - startedAt
                    const remaining = Math.max(0, 1000 - elapsed)
                    if (remaining > 0) {
                        minLoadingTimeoutRef.current = setTimeout(() => {
                            minLoadingTimeoutRef.current = null
                            if (thisRunId === runIdRef.current) setLoading(false)
                        }, remaining)
                    } else {
                        setLoading(false)
                    }
                }
            }
        }

        if (effectiveUpdateMode === 'auto') {
            const debounceTimer = setTimeout(run, RENDER_DEBOUNCE_MS)
            return () => {
                cancelled = true
                clearTimeout(debounceTimer)
                if (minLoadingTimeoutRef.current != null) {
                    clearTimeout(minLoadingTimeoutRef.current)
                    minLoadingTimeoutRef.current = null
                }
                setLoading(false)
            }
        }
        run()
        return () => {
            cancelled = true
            setStreamingMarkdown(null)
            if (minLoadingTimeoutRef.current != null) {
                clearTimeout(minLoadingTimeoutRef.current)
                minLoadingTimeoutRef.current = null
            }
        }
    // Content updates only when connected-node data changes (sourceSignature) or explicit run/viewport.
    // React Flow updates (position, selection, context ref churn) do not trigger re-runs.
    }, [
        id,
        srcId,
        srcNode?.type,
        effectiveUpdateMode,
        runTrigger,
        sourceSignature,
        viewportWidth,
        viewportHeight,
        retryCount,
        incomingIds.length,
    ])

    useEffect(() => {
        if (streamingMarkdown === null) {
            setStreamingPreviewHtml('')
            return
        }
        let cancelled = false
        import('marked')
            .then(async ({ marked }) => {
                if (cancelled) return
                const parsed =
                    typeof marked.parse === 'function'
                        ? await (marked.parse as (s: string) => Promise<string>)(streamingMarkdown)
                        : (marked as (s: string) => string)(streamingMarkdown)
                const str = typeof parsed === 'string' ? parsed : String(parsed)
                if (!cancelled) setStreamingPreviewHtml(str)
            })
            .catch(() => {
                if (!cancelled) setStreamingPreviewHtml(streamingMarkdown)
            })
        return () => {
            cancelled = true
        }
    }, [streamingMarkdown])

    useEffect(() => {
        if (!reasoningContent) {
            setReasoningHtml('')
            return
        }
        let cancelled = false
        import('marked')
            .then(async ({ marked }) => {
                if (cancelled) return
                const parsed =
                    typeof marked.parse === 'function'
                        ? await (marked.parse as (s: string) => Promise<string>)(reasoningContent)
                        : (marked as (s: string) => string)(reasoningContent)
                const str = typeof parsed === 'string' ? parsed : String(parsed)
                if (!cancelled) setReasoningHtml(str)
            })
            .catch(() => {
                if (!cancelled) setReasoningHtml(reasoningContent)
            })
        return () => {
            cancelled = true
        }
    }, [reasoningContent])

    const isSvgOutput = Boolean(
        renderedContent?.trim() && /<svg[\s>]/i.test(renderedContent.trim())
    )
    const renderedThinkSplit = useMemo(() => {
        if (outputType === 'image' || !renderedContent) return { main: '', think: '' }
        return parseThinkSections(renderedContent)
    }, [renderedContent, outputType])
    const streamingThinkSplit = useMemo(() => {
        if (streamingMarkdown === null) return { main: '', think: '' }
        const src = streamingPreviewHtml || streamingMarkdown
        return parseThinkSections(src)
    }, [streamingMarkdown, streamingPreviewHtml])
    const rawDisplayContent = useMemo(() => {
        const src = resolvedContent != null ? resolvedContent : streamingMarkdown ?? ''
        return stripTemplateSyntax(src)
    }, [resolvedContent, streamingMarkdown])
    const displayContent = useMemo(() => {
        if (!renderedContent || !isSvgOutput) return renderedContent
        return processSvgDisplay(renderedContent)
    }, [renderedContent, isSvgOutput])

    const incrementRunTrigger = useCallback(() => {
        updateData({ runTrigger: (data?.runTrigger ?? 0) + 1 })
    }, [data?.runTrigger, updateData])

    const setUpdateMode = useCallback(
        (mode: 'auto' | 'manual') => {
            updateData({ updateMode: mode })
        },
        [updateData]
    )

    const setRetryCount = useCallback((fn: (c: number) => number) => {
        setRetryCountState(fn)
    }, [])

    const emptyStateAction = useMemo(() => {
        if (incomingIds.length > 0) return null
        if (!setNodes || !setEdges) return null
        return {
            label: 'Create Config',
            onClick: () => {
                const nid = getNextNodeId(
                    'config',
                    (nodes as { id: string }[]).map((n) => n.id)
                )
                const thisNode = (nodes as { id: string; position?: { x: number; y: number } }[]).find(
                    (n) => n.id === id
                )
                const pos = thisNode?.position ?? { x: 0, y: 0 }
                const newPos = { x: pos.x - 220, y: pos.y }
                const newNode = {
                    id: nid,
                    type: 'config',
                    position: newPos,
                    data: getDefaultDataForType('config', nid),
                    style: getDefaultStyle('config'),
                }
                setNodes((nds: unknown[]) => nds.concat(newNode) as unknown[])
                setEdges((eds: unknown[]) =>
                    eds.concat({ id: `e-${nid}-${id}`, source: nid, target: id }) as unknown[]
                )
            },
        }
    }, [id, incomingIds.length, nodes, setNodes, setEdges])

    const sourceData = useMemo(() => (srcNode?.data as Record<string, unknown>) ?? {}, [srcNode?.data])
    const sourceNodeType = (srcNode?.type as string) ?? null

    const displayStatus = useMemo<NodeDisplayStatus>(
        () => getNodeDisplayStatus({ loading, error, hasContent: !!renderedContent }),
        [loading, error, renderedContent]
    )

    return {
        displayStatus,
        lifecycle,
        incomingIds,
        effectiveUpdateMode,
        runTrigger,
        hasPendingInputs,
        loading,
        error,
        incrementRunTrigger,
        setRetryCount,
        renderedContent,
        resolvedContent,
        streamingMarkdown,
        streamingPreviewHtml,
        reasoningContent,
        reasoningHtml,
        outputType,
        outputLabel: configType.label,
        rawLanguage: configTypeId,
        isSvgOutput,
        renderedThinkSplit,
        streamingThinkSplit,
        rawDisplayContent,
        displayContent,
        viewportWidth,
        viewportHeight,
        setUpdateMode,
        emptyStateAction,
        sourceData,
        sourceNodeType,
    }
}