import {useEffect, useState} from 'react'
import {CalendarClock, Loader2, Plus, Send, Trash2} from 'lucide-react'
import {useMutation, useQuery, useQueryClient} from '@tanstack/react-query'
import {createEventBridgeRule, deleteEventBridgeRule, listCloudResources, listEventBridgeRules, putEventBridgeEvent, type EventBridgeRuleOverview} from '@/api/cloudProxyClient'
import type {CloudProvider, CloudServiceType} from '@/types/cloud'
import type {CloudResource} from '@/types/resource'
import {ServiceIcon} from '@/components/serviceIcons'

interface EventBridgeRulePanelProps {
    cloud: CloudProvider
    resource?: CloudResource
    runtimeReachable: boolean
}

type TargetService = 'lambda' | 'sqs' | 'sns' | 'step-functions'

const targetServiceDetails: Record<TargetService, {label: string; service: CloudServiceType; matches: (resource: CloudResource) => boolean}> = {
    lambda: {label: 'Lambda', service: 'serverless', matches: (resource) => resource.type === 'lambda'},
    sqs: {label: 'SQS', service: 'messaging', matches: (resource) => resource.type === 'queue' || resource.type === 'fifo-queue'},
    sns: {label: 'SNS', service: 'notifications', matches: (resource) => resource.type === 'topic'},
    'step-functions': {label: 'Step Functions', service: 'workflows', matches: (resource) => resource.type === 'state-machine'},
}

export function EventBridgeRulePanel({cloud, resource, runtimeReachable}: EventBridgeRulePanelProps) {
    const [name, setName] = useState('')
    const [description, setDescription] = useState('')
    const [mode, setMode] = useState<'schedule' | 'event-pattern'>('schedule')
    const [scheduleExpression, setScheduleExpression] = useState('rate(5 minutes)')
    const [eventPattern, setEventPattern] = useState('{\n  "source": ["orders"]\n}')
    const [enabled, setEnabled] = useState(true)
    const [targetService, setTargetService] = useState<TargetService>('lambda')
    const [targetArn, setTargetArn] = useState('')
    const [deleteTarget, setDeleteTarget] = useState<EventBridgeRuleOverview | null>(null)
    const [eventSource, setEventSource] = useState('orders')
    const [eventDetailType, setEventDetailType] = useState('order.created')
    const [eventDetail, setEventDetail] = useState('{\n  "orderId": "example-123"\n}')
    const queryClient = useQueryClient()
    const targetQueries = {
        serverless: useQuery({
            queryKey: ['cloud-resources', cloud, 'serverless'],
            queryFn: ({signal}) => listCloudResources(cloud, 'serverless', undefined, signal),
            enabled: cloud === 'aws' && Boolean(resource) && runtimeReachable,
        }),
        messaging: useQuery({
            queryKey: ['cloud-resources', cloud, 'messaging'],
            queryFn: ({signal}) => listCloudResources(cloud, 'messaging', undefined, signal),
            enabled: cloud === 'aws' && Boolean(resource) && runtimeReachable,
        }),
        notifications: useQuery({
            queryKey: ['cloud-resources', cloud, 'notifications'],
            queryFn: ({signal}) => listCloudResources(cloud, 'notifications', undefined, signal),
            enabled: cloud === 'aws' && Boolean(resource) && runtimeReachable,
        }),
        workflows: useQuery({
            queryKey: ['cloud-resources', cloud, 'workflows'],
            queryFn: ({signal}) => listCloudResources(cloud, 'workflows', undefined, signal),
            enabled: cloud === 'aws' && Boolean(resource) && runtimeReachable,
        }),
    }
    const rulesQuery = useQuery({
        queryKey: ['eventbridge-rules', cloud, resource?.id],
        queryFn: ({signal}) => listEventBridgeRules(cloud, resource!.id, signal),
        enabled: cloud === 'aws' && resource?.service === 'events' && resource.type === 'event-bus' && runtimeReachable,
    })

    useEffect(() => {
        setName('')
        setDescription('')
        setMode('schedule')
        setScheduleExpression('rate(5 minutes)')
        setEventPattern('{\n  "source": ["orders"]\n}')
        setEnabled(true)
        setTargetService('lambda')
        setTargetArn('')
        setDeleteTarget(null)
        setEventSource('orders')
        setEventDetailType('order.created')
        setEventDetail('{\n  "orderId": "example-123"\n}')
    }, [resource?.id])

    const resourcesByTargetService = (Object.keys(targetServiceDetails) as TargetService[]).reduce<Record<TargetService, CloudResource[]>>((resources, service) => {
        const details = targetServiceDetails[service]
        const sourceResources = details.service === 'serverless'
            ? targetQueries.serverless.data ?? []
            : details.service === 'messaging'
                ? targetQueries.messaging.data ?? []
                : details.service === 'notifications'
                    ? targetQueries.notifications.data ?? []
                    : targetQueries.workflows.data ?? []
        resources[service] = sourceResources.filter((candidate) => details.matches(candidate) && typeof candidate.metadata.arn === 'string' && candidate.metadata.arn.length > 0)
        return resources
    }, {lambda: [], sqs: [], sns: [], 'step-functions': []})
    const availableTargetServices = (Object.keys(targetServiceDetails) as TargetService[]).filter((service) => resourcesByTargetService[service].length > 0)
    const targetResources = resourcesByTargetService[targetService]
    const selectedTarget = targetResources.find((candidate) => candidate.metadata.arn === targetArn)
    const patternValid = mode !== 'event-pattern' || isJsonObject(eventPattern)

    useEffect(() => {
        if (availableTargetServices.length > 0 && !availableTargetServices.includes(targetService)) {
            setTargetService(availableTargetServices[0])
            setTargetArn('')
        }
    }, [availableTargetServices, targetService])

    const createMutation = useMutation({
        mutationFn: () => createEventBridgeRule(cloud, resource!.id, {
            name: name.trim(),
            ...(mode === 'schedule' ? {scheduleExpression: scheduleExpression.trim()} : {eventPattern: eventPattern.trim()}),
            state: enabled ? 'ENABLED' : 'DISABLED',
            ...(description.trim() ? {description: description.trim()} : {}),
            targets: [{id: targetId(selectedTarget!), arn: targetArn}],
        }),
        onSuccess: () => {
            setName('')
            setDescription('')
            setTargetArn('')
            void queryClient.invalidateQueries({queryKey: ['eventbridge-rules', cloud, resource?.id]})
        },
    })
    const canCreate = Boolean(name.trim() && targetArn && (mode === 'schedule' ? scheduleExpression.trim() : eventPattern.trim()) && patternValid) && !createMutation.isPending
    const deleteMutation = useMutation({
        mutationFn: (rule: EventBridgeRuleOverview) => deleteEventBridgeRule(cloud, resource!.id, rule.name),
        onSuccess: () => {
            setDeleteTarget(null)
            void queryClient.invalidateQueries({queryKey: ['eventbridge-rules', cloud, resource?.id]})
        },
    })
    const publishMutation = useMutation({
        mutationFn: () => putEventBridgeEvent(cloud, resource!.id, {source: eventSource.trim(), detailType: eventDetailType.trim(), detail: eventDetail.trim()}),
    })
    const eventDetailValid = isJsonObject(eventDetail)
    const canPublish = Boolean(eventSource.trim() && eventDetailType.trim() && eventDetail.trim() && eventDetailValid) && !publishMutation.isPending

    if (!resource || resource.service !== 'events' || resource.type !== 'event-bus') return null

    return <section className="table-panel">
        <div className="dynamic-stage-header">
            <div>
                <p className="eyebrow">EventBridge Rules</p>
                <h3><ServiceIcon cloud="aws" iconKey="events" size={18}/> Add rule to {resource.name}</h3>
                <p className="muted compact-text">Route a schedule or matching events from this event bus to one existing target.</p>
            </div>
        </div>
        <div className="resource-create-inline">
            <form className="inspector-action-form apigateway-route-form" onSubmit={(event) => {
                event.preventDefault()
                if (canCreate) createMutation.mutate()
            }}>
                <label className="dynamic-field"><span>Rule name</span><input className="input" value={name} onChange={(event) => setName(event.target.value)} placeholder="hourly-report" required/></label>
                <label className="dynamic-field"><span>Description</span><input className="input" value={description} onChange={(event) => setDescription(event.target.value)} placeholder="Generate the hourly report"/></label>
                <label className="dynamic-field"><span>Mode</span><select className="input" value={mode} onChange={(event) => setMode(event.target.value as 'schedule' | 'event-pattern')}><option value="schedule">Schedule</option><option value="event-pattern">Event pattern</option></select></label>
                {mode === 'schedule' ? <label className="dynamic-field"><span>Schedule expression</span><input className="input" value={scheduleExpression} onChange={(event) => setScheduleExpression(event.target.value)} placeholder="rate(5 minutes)" required/><small>Use a rate or cron expression.</small></label> : <label className="dynamic-field"><span>Event pattern (JSON)</span><textarea className="textarea code-textarea small" value={eventPattern} onChange={(event) => setEventPattern(event.target.value)} spellCheck={false} required/>{!patternValid && <small className="error-text">Event pattern must be a JSON object.</small>}</label>}
                <label className="dynamic-field"><span>Target service</span><select className="input" value={targetService} onChange={(event) => { setTargetService(event.target.value as TargetService); setTargetArn('') }}>{availableTargetServices.length === 0 ? <option value={targetService}>{targetServiceDetails[targetService].label}</option> : availableTargetServices.map((service) => <option key={service} value={service}>{targetServiceDetails[service].label}</option>)}</select><small>{availableTargetServices.length === 0 ? 'No supported EventBridge targets are available.' : 'Only services with discoverable resources are listed.'}</small></label>
                <label className="dynamic-field"><span>Target resource</span><select className="input" value={targetArn} onChange={(event) => setTargetArn(event.target.value)} required><option value="">Select a {targetServiceDetails[targetService].label} resource</option>{targetResources.map((candidate) => <option key={candidate.id} value={String(candidate.metadata.arn)}>{candidate.name}</option>)}</select><small>{targetResources.length === 0 ? `No ${targetServiceDetails[targetService].label} resources with an ARN are available.` : 'Uses the resource ARN returned by the cloud API.'}</small></label>
                <label className="dynamic-field"><span>State</span><span><input type="checkbox" checked={enabled} onChange={(event) => setEnabled(event.target.checked)}/> Enabled</span></label>
                <div className="apigateway-route-explorer"><p className="eyebrow">Reviewed creation plan</p><p className="muted compact-text">Create EventBridge rule <code>{name.trim() || 'your-rule'}</code> on bus <code>{resource.name}</code> with {mode === 'schedule' ? <code>{scheduleExpression.trim() || 'your schedule'}</code> : 'the supplied event pattern'}, then attach existing {targetServiceDetails[targetService].label} target <code>{selectedTarget?.name || 'your-target'}</code>. No Lambda, SQS queue, SNS topic, or Step Functions resources will be created.</p></div>
                <button className="button primary apigateway-route-submit" type="submit" disabled={!canCreate}>{createMutation.isPending ? <Loader2 size={13}/> : <Plus size={13}/>}{createMutation.isPending ? 'Creating rule' : 'Create rule'}</button>
            </form>
            {createMutation.isError && <p className="error-text compact-text">{createMutation.error instanceof Error ? createMutation.error.message : 'Unable to create EventBridge rule.'}</p>}
        </div>
        <div className="resource-create-inline">
            <div className="dynamic-stage-header"><div><p className="eyebrow">Test event delivery</p><h3><Send size={15}/> Publish to {resource.name}</h3><p className="muted compact-text">Sends one real EventBridge PutEvents entry to this bus.</p></div></div>
            <form className="inspector-action-form apigateway-route-form" onSubmit={(event) => { event.preventDefault(); if (canPublish) publishMutation.mutate() }}>
                <label className="dynamic-field"><span>Source</span><input className="input" value={eventSource} onChange={(event) => setEventSource(event.target.value)} required/></label>
                <label className="dynamic-field"><span>Detail type</span><input className="input" value={eventDetailType} onChange={(event) => setEventDetailType(event.target.value)} required/></label>
                <label className="dynamic-field dynamic-field--span"><span>Detail (JSON)</span><textarea className="textarea code-textarea small" value={eventDetail} onChange={(event) => setEventDetail(event.target.value)} spellCheck={false} required/>{!eventDetailValid && <small className="error-text">Detail must be a JSON object.</small>}</label>
                <button className="button primary apigateway-route-submit" type="submit" disabled={!canPublish}>{publishMutation.isPending ? <Loader2 size={13}/> : <Send size={13}/>}{publishMutation.isPending ? 'Publishing event' : 'Publish event'}</button>
            </form>
            {publishMutation.isSuccess && <p className={publishMutation.data.errorCode ? 'error-text compact-text' : 'success-text compact-text'}>{publishMutation.data.errorCode ? `${publishMutation.data.errorCode}: ${publishMutation.data.errorMessage}` : `Published event ${publishMutation.data.eventId}`}</p>}
            {publishMutation.isError && <p className="error-text compact-text">{publishMutation.error instanceof Error ? publishMutation.error.message : 'Unable to publish EventBridge event.'}</p>}
        </div>
        <div className="apigateway-route-explorer">
            <div className="dynamic-stage-header"><div><p className="eyebrow">Configured Rules</p><h3><CalendarClock size={15}/> Rules and targets</h3></div></div>
            {rulesQuery.isLoading && <p className="muted compact-text">Loading EventBridge rules...</p>}
            {rulesQuery.isError && <p className="error-text compact-text">{rulesQuery.error instanceof Error ? rulesQuery.error.message : 'Unable to load EventBridge rules.'}</p>}
            {rulesQuery.data?.length === 0 && <p className="muted compact-text">No rules configured for this event bus.</p>}
            {rulesQuery.data?.map((rule) => <div className="apigateway-route-item" key={rule.name}><div className="apigateway-route-select"><span className="apigateway-route-method">{rule.state}</span><code>{rule.name}</code><small>{rule.scheduleExpression ?? rule.eventPattern ?? 'No pattern'}{rule.description ? ` · ${rule.description}` : ''}</small>{rule.targets.map((target) => <small key={target.id}>Target {target.id}: <code>{target.arn}</code></small>)}</div>{deleteTarget?.name === rule.name ? <div className="apigateway-route-confirm"><span>Delete rule?</span><button className="button danger compact" type="button" disabled={deleteMutation.isPending} onClick={() => deleteMutation.mutate(rule)}>Delete</button><button className="button compact" type="button" disabled={deleteMutation.isPending} onClick={() => setDeleteTarget(null)}>Cancel</button></div> : <button className="icon-btn" type="button" aria-label={`Delete rule ${rule.name}`} onClick={() => setDeleteTarget(rule)}><Trash2 size={13}/></button>}</div>)}
        </div>
    </section>
}

function isJsonObject(value: string): boolean {
    try {
        const parsed: unknown = JSON.parse(value)
        return Boolean(parsed) && typeof parsed === 'object' && !Array.isArray(parsed)
    } catch {
        return false
    }
}

function targetId(resource: CloudResource): string {
    return resource.id.replace(/[^A-Za-z0-9_.-]/g, '-').slice(0, 64) || 'target'
}