#!/usr/bin/env bun

async function sendToPostHog(event: string, properties: Record<string, any>) {
 const key = process.env["POSTHOG_KEY"]

 if (!key) {
 console.warn("POSTHOG_API_KEY not set, skipping PostHog event")
 return
 }

 const response = await fetch("https://us.i.posthog.com/i/v0/e/", {
 method: "POST",
 headers: {
 "Content-Type": "application/json",
 },
 body: JSON.stringify({
 distinct_id: "download",
 api_key: key,
 event,
 properties: {
 ...properties,
 },
 }),
 }).catch(() => null)

 if (response && !response.ok) {
 console.warn(`PostHog API error: ${response.status}`)
 }
}

interface Asset {
 name: string
 download_count: number
}

interface Release {
 tag_name: string
 name: string
 assets: Asset[]
}

interface NpmDownloadsRange {
 start: string
 end: string
 package: string
 downloads: Array<{
 downloads: number
 day: string
 }>
}

async function fetchNpmDownloads(packageName: string): Promise<number> {
 try {
 // Use a range from 2020 to current year + 5 years to ensure it works forever
 const currentYear = new Date().getFullYear()
 const endYear = currentYear + 5
 const response = await fetch(`https://api.npmjs.org/downloads/range/2020-01-01:${endYear}-12-31/${packageName}`)
 if (!response.ok) {
 console.warn(`Failed to fetch npm downloads for ${packageName}: ${response.status}`)
 return 0
 }
 const data: NpmDownloadsRange = await response.json()
 return data.downloads.reduce((total, day) => total + day.downloads, 0)
 } catch (error) {
 console.warn(`Error fetching npm downloads for ${packageName}:`, error)
 return 0
 }
}

async function fetchReleases(): Promise<Release[]> {
 const releases: Release[] = []
 let page = 1
 const per = 100

 while (true) {
 const url = `https://api.github.com/repos/anomalyco/opencode/releases?page=${page}&per_page=${per}`

 const response = await fetch(url)
 if (!response.ok) {
 throw new Error(`GitHub API error: ${response.status}${response.statusText}`)
 }

 const batch: Release[] = await response.json()
 if (batch.length === 0) break

 releases.push(...batch)
 console.log(`Fetched page ${page} with ${batch.length} releases`)

 if (batch.length < per) break
 page++
 await new Promise((resolve) => setTimeout(resolve, 1000))
 }

 return releases
}

function calculate(releases: Release[]) {
 let total = 0
 const stats = []

 for (const release of releases) {
 let downloads = 0
 const assets = []

 for (const asset of release.assets) {
 downloads += asset.download_count
 assets.push({
 name: asset.name,
 downloads: asset.download_count,
 })
 }

 total += downloads
 stats.push({
 tag: release.tag_name,
 name: release.name,
 downloads,
 assets,
 })
 }

 return { total, stats }
}

async function save(githubTotal: number, npmDownloads: number) {
 const file = "STATS.md"
 const date = new Date().toISOString().split("T")[0]
 const total = githubTotal + npmDownloads

 let previousGithub = 0
 let previousNpm = 0
 let previousTotal = 0
 let content = ""

 try {
 content = await Bun.file(file).text()
 const lines = content.trim().split("\n")

 for (let i = lines.length - 1; i >= 0; i--) {
 const line = lines[i].trim()
 if (line.startsWith("|") && !line.includes("Date") && !line.includes("---")) {
 const match = line.match(
 /\|\s*[\d-]+\s*\|\s*([\d,]+)\s*(?:\([^)]*\))?\s*\|\s*([\d,]+)\s*(?:\([^)]*\))?\s*\|\s*([\d,]+)\s*(?:\([^)]*\))?\s*\|/,
 )
 if (match) {
 previousGithub = parseInt(match[1].replace(/,/g, ""))
 previousNpm = parseInt(match[2].replace(/,/g, ""))
 previousTotal = parseInt(match[3].replace(/,/g, ""))
 break
 }
 }
 }
 } catch {
 content =
 "# Download Stats\n\n| Date | GitHub Downloads | npm Downloads | Total |\n|------|------------------|---------------|-------|\n"
 }

 const githubChange = githubTotal - previousGithub
 const npmChange = npmDownloads - previousNpm
 const totalChange = total - previousTotal

 const githubChangeStr =
 githubChange > 0
 ? ` (+${githubChange.toLocaleString()})`
 : githubChange < 0
 ? ` (${githubChange.toLocaleString()})`
 : " (+0)"
 const npmChangeStr =
 npmChange > 0 ? ` (+${npmChange.toLocaleString()})` : npmChange < 0 ? ` (${npmChange.toLocaleString()})` : " (+0)"
 const totalChangeStr =
 totalChange > 0
 ? ` (+${totalChange.toLocaleString()})`
 : totalChange < 0
 ? ` (${totalChange.toLocaleString()})`
 : " (+0)"
 const line = `| ${date} | ${githubTotal.toLocaleString()}${githubChangeStr} | ${npmDownloads.toLocaleString()}${npmChangeStr} | ${total.toLocaleString()}${totalChangeStr} |\n`

 if (!content.includes("# Download Stats")) {
 content =
 "# Download Stats\n\n| Date | GitHub Downloads | npm Downloads | Total |\n|------|------------------|---------------|-------|\n"
 }

 await Bun.write(file, content + line)
 await Bun.spawn(["bunx", "prettier", "--write", file]).exited

 console.log(
 `\nAppended stats to ${file}: GitHub ${githubTotal.toLocaleString()}${githubChangeStr}, npm ${npmDownloads.toLocaleString()}${npmChangeStr}, Total ${total.toLocaleString()}${totalChangeStr}`,
 )
}

console.log("Fetching GitHub releases for anomalyco/opencode...\n")

const releases = await fetchReleases()
console.log(`\nFetched ${releases.length} releases total\n`)

const { total: githubTotal } = calculate(releases)

console.log("Fetching npm all-time downloads for opencode-ai...\n")
const npmDownloads = await fetchNpmDownloads("opencode-ai")
console.log(`Fetched npm all-time downloads: ${npmDownloads.toLocaleString()}\n`)

await save(githubTotal, npmDownloads)

await sendToPostHog("download", {
 count: githubTotal,
 source: "github",
})

await sendToPostHog("download", {
 count: npmDownloads,
 source: "npm",
})

const totalDownloads = githubTotal + npmDownloads

console.log("=".repeat(60))
console.log(`TOTAL DOWNLOADS: ${totalDownloads.toLocaleString()}`)
console.log(` GitHub: ${githubTotal.toLocaleString()}`)
console.log(` npm: ${npmDownloads.toLocaleString()}`)
console.log("=".repeat(60))

console.log("-".repeat(60))
console.log(`GitHub Total: ${githubTotal.toLocaleString()} downloads across ${releases.length} releases`)
console.log(`npm Total: ${npmDownloads.toLocaleString()} downloads`)
console.log(`Combined Total: ${totalDownloads.toLocaleString()} downloads`)