import { existsSync, readdirSync, readFileSync, statSync } from 'node:fs'
import { basename, join, relative } from 'node:path'
import type { Agent, BlobRef } from '@atproto/api'
import {
	compressFile,
	computeCID,
	extractBlobMap,
	extractSubfsUris,
	isTextMimeType,
	shouldCompressFile,
} from '@wispplace/atproto-utils'
import { DEFAULT_IGNORE_PATTERNS, MAX_FILE_COUNT, MAX_FILE_SIZE, MAX_SITE_SIZE } from '@wispplace/constants'
import {
	countFilesInDirectory,
	createManifest,
	estimateDirectorySize,
	type FileUploadResult,
	findLargeDirectories,
	processUploadedFiles,
	replaceDirectoryWithSubfs,
	splitDirectoryIntoChunks,
	type UploadedFile,
	updateFileBlobs,
} from '@wispplace/fs-utils'
import type { Directory, Record as FsRecord } from '@wispplace/lexicons/types/place/wisp/fs'
import type { Record as SettingsRecord } from '@wispplace/lexicons/types/place/wisp/settings'
import type { Record as SubfsRecord } from '@wispplace/lexicons/types/place/wisp/subfs'
import ignore, { type Ignore } from 'ignore'
import { lookup } from 'mime-types'
import { createSpinner, formatBytes, pc } from '../lib/progress.ts'

// Constants for manifest splitting
const MAX_MANIFEST_SIZE = 140 * 1024 // 140KB (PDS limit is 150KB)
const FILE_COUNT_THRESHOLD = 250
const TARGET_FILE_COUNT = 200
const MAX_SUBFS_SIZE = 75 * 1024 // 75KB per subfs
const DEFAULT_CONCURRENT_UPLOADS = 3
const RATELIMITED_CONCURRENT_UPLOADS = 2

export interface DeployOptions {
	path: string
	site?: string
	directory?: boolean
	spa?: boolean
	yes?: boolean
	concurrency?: number
	forceGzip?: boolean
}

interface FileInfo {
	path: string
	relativePath: string
	size: number
}

function createIgnoreMatcher(siteDir: string): Ignore {
	const ig = ignore()
	ig.add(DEFAULT_IGNORE_PATTERNS)

	// Load custom .wispignore if exists
	const wispignorePath = join(siteDir, '.wispignore')
	if (existsSync(wispignorePath)) {
		const content = readFileSync(wispignorePath, 'utf-8')
		const patterns = content
			.split('\n')
			.map((l) => l.trim())
			.filter((l) => l && !l.startsWith('#'))
		ig.add(patterns)
	}

	return ig
}

function toUnixPath(p: string): string {
	// A backslash is a path separator on Windows
	if (process.platform === "win32") {
		return p.replace(/\\/g, "/")
	}
	// on Unix systems, you're typically allowed to have backslashes in file names
	return p
}

function collectFiles(dir: string, ig: Ignore, baseDir: string): FileInfo[] {
	const files: FileInfo[] = []

	const entries = readdirSync(dir, { withFileTypes: true })
	for (const entry of entries) {
		const fullPath = join(dir, entry.name)
		const relativePath = toUnixPath(relative(baseDir, fullPath))

		// The ignore package needs trailing '/' for directory-pattern matching
		const isDir = entry.isDirectory()
		if (ig.ignores(isDir ? `${relativePath}/` : relativePath)) continue

		if (isDir) {
			files.push(...collectFiles(fullPath, ig, baseDir))
		} else if (entry.isFile()) {
			const stat = statSync(fullPath)
			files.push({
				path: fullPath,
				relativePath,
				size: stat.size,
			})
		}
	}

	return files
}

async function fetchExistingManifest(
	agent: Agent,
	did: string,
	rkey: string,
): Promise<{ record: FsRecord; blobMap: Map<string, { blobRef: BlobRef; cid: string }> } | null> {
	try {
		const response = await agent.com.atproto.repo.getRecord({
			repo: did,
			collection: 'place.wisp.fs',
			rkey,
		})

		const record = response.data.value as FsRecord
		const blobMap = extractBlobMap(record.root)

		// Also fetch any subfs records and merge their blob maps
		const subfsUris = extractSubfsUris(record.root)
		for (const { uri } of subfsUris) {
			try {
				const parts = uri.replace('at://', '').split('/')
				const subfsRepo = parts[0]!
				const subfsRkey = parts[2]!

				const subfsResponse = await agent.com.atproto.repo.getRecord({
					repo: subfsRepo,
					collection: 'place.wisp.subfs',
					rkey: subfsRkey,
				})

				const subfsRecord = subfsResponse.data.value as SubfsRecord
				const subfsBlobMap = extractBlobMap(subfsRecord.root as unknown as Directory)
				for (const [key, value] of subfsBlobMap) blobMap.set(key, value)
			} catch {
				// Subfs not found, skip
			}
		}

		return { record, blobMap }
	} catch {
		return null
	}
}

async function uploadBlob(
	agent: Agent,
	content: Buffer,
	mimeType: string,
	retries = 3,
	onRateLimit?: () => void,
): Promise<BlobRef> {
	for (let attempt = 0; attempt < retries; attempt++) {
		try {
			const response = await agent.com.atproto.repo.uploadBlob(content, {
				encoding: mimeType,
			})
			return response.data.blob
		} catch (err: any) {
			if (attempt === retries - 1) throw err

			// Handle rate limits
			if (err?.status === 429) {
				onRateLimit?.()
				const delay = 2 ** attempt * 2000
				await new Promise((r) => setTimeout(r, delay))
			} else {
				const delay = 2 ** attempt * 500
				await new Promise((r) => setTimeout(r, delay))
			}
		}
	}
	throw new Error('Failed to upload blob after retries')
}

async function processAndUploadFiles(
	agent: Agent,
	files: FileInfo[],
	existingBlobMap: Map<string, { blobRef: BlobRef; cid: string }>,
	concurrency: number,
	useBase64 = false,
	forceGzip = false,
): Promise<{ uploadedFiles: UploadedFile[]; uploadResults: FileUploadResult[]; filePaths: string[] }> {
	const spinner = createSpinner(`Processing ${files.length} files...`).start()

	const uploadedFiles: UploadedFile[] = []
	const uploadResults: FileUploadResult[] = []
	const filePaths: string[] = []

	let uploaded = 0
	let reused = 0
	let currentConcurrency = concurrency

	const onRateLimit = () => {
		const reduced = Math.min(currentConcurrency, RATELIMITED_CONCURRENT_UPLOADS)
		if (reduced < currentConcurrency) {
			currentConcurrency = reduced
			spinner.text = `Rate limited — reducing concurrency to ${currentConcurrency}`
		}
	}

	// Process in batches for concurrency
	for (let i = 0; i < files.length; i += currentConcurrency) {
		const batch = files.slice(i, i + currentConcurrency)

		await Promise.all(
			batch.map(async (file) => {
				const content = readFileSync(file.path)
				const mimeType = lookup(file.relativePath) || 'application/octet-stream'
				const shouldCompress = forceGzip || shouldCompressFile(mimeType, file.relativePath)

				let processedContent: Buffer
				let encoding: 'gzip' | undefined
				let base64Encoded = false

				if (shouldCompress) {
					const compressed = compressFile(content)
					if (!forceGzip && useBase64 && isTextMimeType(mimeType)) {
						// Fallback: base64-encode compressed text files for PDSes that reject them otherwise
						processedContent = Buffer.from(compressed.toString('base64'), 'binary')
						base64Encoded = true
					} else {
						processedContent = compressed
					}
					encoding = 'gzip'
				} else {
					processedContent = content
				}

				// Compute CID
				const cid = computeCID(processedContent)

				// Check if blob already exists
				const existing = existingBlobMap.get(file.relativePath)
				let blobRef: BlobRef

				if (existing && existing.cid === cid) {
					// Reuse existing blob
					blobRef = existing.blobRef
					reused++
				} else {
					// Upload new blob
					blobRef = await uploadBlob(agent, processedContent, 'application/octet-stream', 3, onRateLimit)
					uploaded++
				}

				uploadedFiles.push({
					name: file.relativePath,
					content: processedContent,
					mimeType,
					size: processedContent.length,
					compressed: shouldCompress,
					...(base64Encoded && { base64Encoded }),
					originalMimeType: mimeType,
				})

				uploadResults.push({
					hash: cid,
					blobRef,
					encoding,
					mimeType,
					base64: base64Encoded,
				})

				filePaths.push(file.relativePath)

				spinner.text = `Processing files: ${uploaded + reused}/${files.length} (${uploaded} uploaded, ${reused} reused)`
			}),
		)
	}

	spinner.succeed(`Processed ${files.length} files (${uploaded} uploaded, ${reused} reused)`)

	return { uploadedFiles, uploadResults, filePaths }
}

async function createSubfsRecord(agent: Agent, did: string, directory: Directory, rkey: string): Promise<string> {
	const record = {
		$type: 'place.wisp.subfs' as const,
		root: directory as any, // fs Directory and subfs Directory are compatible at runtime
		fileCount: countFilesInDirectory(directory),
		createdAt: new Date().toISOString(),
	}

	await agent.com.atproto.repo.putRecord({
		repo: did,
		collection: 'place.wisp.subfs',
		rkey,
		record,
	})

	return `at://${did}/place.wisp.subfs/${rkey}`
}

async function splitIntoSubfs(
	agent: Agent,
	did: string,
	directory: Directory,
	siteRkey: string,
): Promise<{ directory: Directory; subfsRkeys: string[] }> {
	const spinner = createSpinner('Splitting large site into subfs records...').start()
	const subfsRkeys: string[] = []
	let currentDir = directory
	let currentFileCount = countFilesInDirectory(currentDir)
	let iteration = 0
	let chunkCounter = 0

	let manifest = createManifest(siteRkey, currentDir, currentFileCount)
	let manifestSize = JSON.stringify(manifest).length

	while ((manifestSize > MAX_MANIFEST_SIZE || currentFileCount > TARGET_FILE_COUNT) && iteration < 100) {
		iteration++

		// Find all directories sorted by size (largest first)
		const directories = findLargeDirectories(currentDir)
		directories.sort((a, b) => b.size - a.size)

		if (directories.length > 0) {
			const largest = directories[0]!
			spinner.text = `Split #${iteration}: ${largest.path} (${largest.fileCount} files, ${formatBytes(largest.size)})`

			let subfsUri: string

			// Check if directory is too large for a single subfs record
			if (largest.size > MAX_SUBFS_SIZE) {
				// Split into chunks
				console.log(pc.dim(`\n    → Directory too large (${formatBytes(largest.size)}), splitting into chunks...`))
				const chunks = splitDirectoryIntoChunks(largest.directory, MAX_SUBFS_SIZE)
				console.log(pc.dim(`    → Created ${chunks.length} chunks`))

				// Upload each chunk as a subfs record
				const chunkUris: string[] = []
				for (let i = 0; i < chunks.length; i++) {
					const chunk = chunks[i]!
					const chunkRkey = `${siteRkey}-chunk-${chunkCounter++}`
					const chunkSize = estimateDirectorySize(chunk)
					const chunkFileCount = countFilesInDirectory(chunk)

					console.log(
						pc.dim(
							`    → Uploading chunk ${i + 1}/${chunks.length} (${chunkFileCount} files, ${formatBytes(chunkSize)})...`,
						),
					)

					const chunkUri = await createSubfsRecord(agent, did, chunk, chunkRkey)
					chunkUris.push(chunkUri)
					subfsRkeys.push(chunkRkey)
				}

				// Create parent subfs that references all chunks with flat: true
				console.log(pc.dim(`    → Creating parent subfs with ${chunkUris.length} chunk references...`))

				const parentEntries = chunkUris.map((uri, i) => ({
					name: `chunk${i}`,
					node: {
						$type: 'place.wisp.fs#subfs' as const,
						type: 'subfs' as const,
						subject: uri,
						flat: true,
					},
				}))

				const parentDirectory: Directory = {
					$type: 'place.wisp.fs#directory' as const,
					type: 'directory' as const,
					entries: parentEntries,
				}

				const parentRkey = `${siteRkey}-subfs-${iteration}`
				subfsUri = await createSubfsRecord(agent, did, parentDirectory, parentRkey)
				subfsRkeys.push(parentRkey)

				console.log(pc.green(`    ✓ Created parent subfs with ${chunks.length} chunks`))
			} else {
				// Directory fits in a single subfs record
				const subfsRkey = `${siteRkey}-subfs-${iteration}`
				subfsUri = await createSubfsRecord(agent, did, largest.directory, subfsRkey)
				subfsRkeys.push(subfsRkey)
			}

			// Replace directory with subfs reference
			currentDir = replaceDirectoryWithSubfs(currentDir, largest.path, subfsUri)
			currentFileCount -= largest.fileCount
		} else {
			// No subdirectories — split flat files at root level
			const rootFiles = currentDir.entries.filter((e) => 'type' in e.node && e.node.type === 'file')

			if (rootFiles.length === 0) {
				spinner.fail(
					`Cannot split further — no files or directories available (${currentFileCount} files, ${(manifestSize / 1024).toFixed(1)}KB)`,
				)
				break
			}

			// Take a chunk of ~100 files
			const CHUNK_SIZE = 100
			const chunkFiles = rootFiles.slice(0, Math.min(CHUNK_SIZE, rootFiles.length))
			spinner.text = `Split #${iteration}: flat root (${chunkFiles.length} files)`

			// Create a directory with just these files
			const chunkDirectory: Directory = {
				$type: 'place.wisp.fs#directory' as const,
				type: 'directory' as const,
				entries: chunkFiles,
			}

			const subfsRkey = `${siteRkey}-subfs-${iteration}`
			const subfsUri = await createSubfsRecord(agent, did, chunkDirectory, subfsRkey)
			subfsRkeys.push(subfsRkey)

			// Remove chunked files and add a flat subfs entry
			const remainingEntries = currentDir.entries.filter((e) => !chunkFiles.some((cf) => cf.name === e.name))

			remainingEntries.push({
				name: `__subfs_${iteration}`,
				node: {
					$type: 'place.wisp.fs#subfs' as const,
					type: 'subfs' as const,
					subject: subfsUri,
					flat: true,
				},
			})

			currentDir = {
				$type: 'place.wisp.fs#directory' as const,
				type: 'directory' as const,
				entries: remainingEntries,
			}

			currentFileCount -= chunkFiles.length
		}

		// Recreate manifest and check new size
		manifest = createManifest(siteRkey, currentDir, currentFileCount)
		manifestSize = JSON.stringify(manifest).length
	}

	spinner.succeed(`Created ${subfsRkeys.length} subfs records`)

	return { directory: currentDir, subfsRkeys }
}

async function deleteOldSubfsRecords(
	agent: Agent,
	did: string,
	oldRecord: FsRecord | null,
	newSubfsRkeys: string[],
): Promise<void> {
	if (!oldRecord) return

	const oldSubfsUris = extractSubfsUris(oldRecord.root)
	const newSubfsSet = new Set(newSubfsRkeys)

	for (const { uri } of oldSubfsUris) {
		const parts = uri.replace('at://', '').split('/')
		const rkey = parts[2]
		if (rkey && !newSubfsSet.has(rkey)) {
			try {
				await agent.com.atproto.repo.deleteRecord({
					repo: did,
					collection: 'place.wisp.subfs',
					rkey,
				})
			} catch {
				// Ignore deletion errors
			}
		}
	}
}

export async function deploy(agent: Agent, did: string, options: DeployOptions): Promise<{ uri: string; url: string }> {
	const siteDir = options.path
	const siteName = options.site || basename(siteDir)

	// Validate site name (AT Protocol rkey format)
	if (!/^[a-zA-Z0-9._~:-]{1,512}$/.test(siteName)) {
		throw new Error(`Invalid site name: ${siteName}. Must be 1-512 chars of [a-zA-Z0-9._~:-]`)
	}

	console.log(pc.cyan(`\nDeploying ${pc.bold(siteName)} from ${siteDir}\n`))

	// 1. Collect files
	const spinner = createSpinner('Scanning directory...').start()
	const ig = createIgnoreMatcher(siteDir)
	const files = collectFiles(siteDir, ig, siteDir)

	if (files.length === 0) {
		spinner.fail('No files found to deploy')
		throw new Error('No files found')
	}

	const totalSize = files.reduce((sum, f) => sum + f.size, 0)
	spinner.succeed(`Found ${files.length} files (${formatBytes(totalSize)})`)

	// 2. Validate limits
	if (files.length > MAX_FILE_COUNT) {
		console.log(pc.yellow(`\nWarning: Site has ${files.length} files (limit: ${MAX_FILE_COUNT})`))
		console.log(pc.yellow('Site may not be cached by the hosting service.\n'))
	}

	if (totalSize > MAX_SITE_SIZE) {
		console.log(pc.yellow(`\nWarning: Site is ${formatBytes(totalSize)} (limit: ${formatBytes(MAX_SITE_SIZE)})`))
		console.log(pc.yellow('Site may not be cached by the hosting service.\n'))
	}

	// Check individual file sizes
	for (const file of files) {
		if (file.size > MAX_FILE_SIZE) {
			console.log(pc.yellow(`\nWarning: ${file.relativePath} exceeds max size (${formatBytes(file.size)} > ${formatBytes(MAX_FILE_SIZE)})`))
			console.log(pc.yellow('This file may not be cached by the hosting service.\n'))
		}
	}

	// 3. Fetch existing manifest for incremental upload
	const existingSpinner = createSpinner('Checking for existing site...').start()
	const existing = await fetchExistingManifest(agent, did, siteName)
	const existingBlobMap = existing?.blobMap || new Map()

	if (existing) {
		existingSpinner.succeed('Found existing site, will reuse unchanged files')
	} else {
		existingSpinner.succeed('No existing site found, uploading all files')
	}

	// 4. Process and upload files
	const concurrency = options.concurrency ?? DEFAULT_CONCURRENT_UPLOADS
	const forceGzip = options.forceGzip ?? false
	const { uploadedFiles, uploadResults, filePaths } = await processAndUploadFiles(
		agent,
		files,
		existingBlobMap,
		concurrency,
		false,
		forceGzip,
	)

	// 5. Build directory structure
	// CLI paths are already relative to site directory, so skip normalization
	const { directory: rawDirectory, fileCount } = processUploadedFiles(uploadedFiles, { skipNormalization: true })
	const successfulPaths = new Set(filePaths)
	const directory = updateFileBlobs(rawDirectory, uploadResults, filePaths, '', successfulPaths, {
		skipNormalization: true,
	})

	// 6+7. Create manifest and put record, retrying with base64 on 500
	const manifestSpinner = createSpinner('Creating manifest...').start()

	// Returns subfsRkeys created so old ones can be cleaned up.
	const attemptManifest = async (useBase64: boolean): Promise<string[]> => {
		let curDirectory = directory

		if (useBase64) {
			// Re-upload only compressed text files with base64 encoding.
			// Re-read from disk so we don't hold duplicate buffers in memory.
			const textFiles = files.filter((f) => {
				const mimeType = lookup(f.relativePath) || 'application/octet-stream'
				return shouldCompressFile(mimeType, f.relativePath) && isTextMimeType(mimeType)
			})
			const retryResult = await processAndUploadFiles(agent, textFiles, existingBlobMap, concurrency, true, forceGzip)

			// Merge updated results back: replace matching paths
			const retryMap = new Map(retryResult.filePaths.map((p, i) => [p, retryResult.uploadResults[i]!]))
			const mergedResults = uploadResults.map((r, i) => retryMap.get(filePaths[i]!) ?? r)

			// Rebuild directory with updated blob refs
			curDirectory = updateFileBlobs(rawDirectory, mergedResults, filePaths, '', new Set(filePaths), {
				skipNormalization: true,
			})
		}

		let finalDirectory = curDirectory
		let subfsRkeys: string[] = []

		if (
			fileCount >= FILE_COUNT_THRESHOLD ||
			JSON.stringify(createManifest(siteName, curDirectory, fileCount)).length > MAX_MANIFEST_SIZE
		) {
			const result = await splitIntoSubfs(agent, did, curDirectory, siteName)
			finalDirectory = result.directory
			subfsRkeys = result.subfsRkeys
		}

		const manifest = createManifest(siteName, finalDirectory, countFilesInDirectory(finalDirectory))
		await agent.com.atproto.repo.putRecord({
			repo: did,
			collection: 'place.wisp.fs',
			rkey: siteName,
			record: manifest,
		})
		return subfsRkeys
	}

	let subfsRkeys: string[]
	try {
		subfsRkeys = await attemptManifest(false)
	} catch (err: any) {
		if (err?.status !== 500) throw err
		console.warn('\n[Deploy] Manifest put failed with 500, retrying with base64 encoding for text files...')
		subfsRkeys = await attemptManifest(true)
	}

	manifestSpinner.succeed('Created manifest record')

	// 8. Clean up old subfs records
	await deleteOldSubfsRecords(agent, did, existing?.record || null, subfsRkeys)

	// 9. Create settings if requested
	if (options.directory || options.spa) {
		const settingsSpinner = createSpinner('Creating settings...').start()

		const settings: SettingsRecord = {
			$type: 'place.wisp.settings',
			directoryListing: options.directory || false,
			cleanUrls: true,
			...(options.spa && { spaMode: 'index.html' }),
		}

		await agent.com.atproto.repo.putRecord({
			repo: did,
			collection: 'place.wisp.settings',
			rkey: siteName,
			record: settings,
		})

		settingsSpinner.succeed('Created settings record')
	}

	const uri = `at://${did}/place.wisp.fs/${siteName}`
	const url = `https://sites.wisp.place/${did}/${siteName}`

	return { uri, url }
}