import { toUTF8 } from "./jdutil"

export function oops(msg: string): never {

throw new Error(msg)

}

export function assert(cond: boolean, msg = "") {

if (!cond) oops("assertion failed" + (msg ? ": " + msg : ""))

}

export function assertRange(

min: number,

v: number,

max: number,

desc = "value"

) {

if (min <= v && v <= max) return

oops(`${desc}=${v} out of range [${min}, ${max}]`)

}

export function strlen(s: string) {

return toUTF8(s).length

}

// inverse of camelize()

// setAll -> set_all

export function snakify(s: string) {

const up = s.toUpperCase()

const lo = s.toLowerCase()

// if the name is all lowercase or all upper case don't do anything

if (s == up || s == lo) return s

// if the name already has underscores (not as first character), leave it alone

if (s.lastIndexOf("_") > 0) return s

const isUpper = (i: number) => s[i] != lo[i]

const isLower = (i: number) => s[i] != up[i]

//const isDigit = (i: number) => /\d/.test(s[i])

let r = ""

let i = 0

while (i < s.length) {

let upperMode = isUpper(i)

let j = i

while (j < s.length) {

if (upperMode && isLower(j)) {

// ABCd -> AB_Cd

if (j - i > 2) {

j--

break

} else {

// ABdefQ -> ABdef_Q

upperMode = false

}

}

// abcdE -> abcd_E

if (!upperMode && isUpper(j)) {

break

}

j++

}

if (r) r += "_"

r += s.slice(i, j)

i = j

}

// If the name is is all caps (like a constant), preserve it

if (r.toUpperCase() === r) {

return r

}

return r.toLowerCase()

}

export function camelize(name: string) {

if (!name) return name

return (

name[0].toLowerCase() +

name

.slice(1)

.replace(/\s+/g, "_")

.replace(/_([a-z0-9])/gi, (_, l) => l.toUpperCase())

)

}

export function upperCamel(name: string) {

name = camelize(name)

if (!name?.length) return name

return name[0].toUpperCase() + name.slice(1)

}

export function addUnique<T>(arr: T[], v: T) {

let idx = arr.indexOf(v)

if (idx < 0) {

idx = arr.length

arr.push(v)

}

return idx

}

export function numSetBits(n: number) {

let r = 0

for (let i = 0; i < 32; ++i) if (n & (1 << i)) r++

return r

}