/**
* Dev-only error overlay. When a loader/action/render throws during `@nifrajs/web/vite` dev, this
* renders a readable full-page overlay from a structured [Diagnostic] - the code, the message, a source
* codeframe around the offending line, the recognised cause/fix when nifra has one, and the stack -
* instead of a bare `err.stack` text dump. Dev-only by construction: it's called solely from the dev
* server's catch, never in production (production maps errors to the `_error` route boundary).
*
* The overlay and the agent surfaces (`/__nifra/last-error`, `nifra_explain`) render from the SAME
* `Diagnostic`, so a person and an agent see the identical failure, one as HTML and one as JSON.
*/
import type { Diagnostic } from "./diagnostic.ts"
const esc = (s: string): string =>
s.replace(/&/g, "&").replace(//g, ">").replace(/"/g, """)
/** The source codeframe block: numbered lines with the offending one highlighted. */
function codeframeHtml(diagnostic: Diagnostic): string {
const cf = diagnostic.codeframe
if (cf === undefined) return ""
const loc = `${esc(cf.file)}:${cf.line}${cf.column !== undefined ? `:${cf.column}` : ""}`
const rows = cf.lines
.map(
(l) =>
`
${l.number}${esc(l.text) || " "}
`,
)
.join("")
return `
Source
${loc}
${rows}
`
}
/** The recognised-failure callout: cause + fix + docs anchor, shown only when nifra classified the error. */
function fixHtml(diagnostic: Diagnostic): string {
if (diagnostic.fix === undefined) return ""
const anchor =
diagnostic.docsAnchor !== undefined
? `