import { describe, expect, test } from "bun:test"

import { Patch } from "@opencode-ai/core/patch"

describe("Patch", () => {

test("parses add, update, and delete hunks", () => {

expect(

Patch.parse(

"*** Begin Patch\n*** Add File: add.txt\n+added\n*** Update File: update.txt\n@@ section\n-old\n+new\n*** Delete File: delete.txt\n*** End Patch",

),

).toEqual([

{ type: "add", path: "add.txt", contents: "added" },

{

type: "update",

path: "update.txt",

chunks: [{ oldLines: ["old"], newLines: ["new"], changeContext: "section", endOfFile: undefined }],

movePath: undefined,

},

{ type: "delete", path: "delete.txt" },

])

})

test("strips a heredoc wrapper", () => {

expect(Patch.parse("cat <<'EOF'\n*** Begin Patch\n*** Add File: add.txt\n+added\n*** End Patch\nEOF")).toEqual([

{ type: "add", path: "add.txt", contents: "added" },

])

})

test("derives fuzzy line updates while preserving BOM", () => {

const update = Patch.derive("update.txt", [{ oldLines: [" old "], newLines: ["new"] }], "\uFEFFold\n")

expect(update).toEqual({ content: "new\n", bom: true })

expect(Patch.joinBom(update.content, update.bom)).toBe("\uFEFFnew\n")

})

test("matches EOF-anchored chunks from the end", () => {

expect(

Patch.derive(

"update.txt",

[{ oldLines: ["marker", "end"], newLines: ["marker changed", "end"], endOfFile: true }],

"marker\nmiddle\nmarker\nend\n",

).content,

).toBe("marker\nmiddle\nmarker changed\nend\n")

})

test("parses the EOF marker inside update chunks", () => {

expect(

Patch.parse("*** Begin Patch\n*** Update File: update.txt\n@@\n-last\n+end\n*** End of File\n*** End Patch"),

).toEqual([

{

type: "update",

path: "update.txt",

movePath: undefined,

chunks: [{ oldLines: ["last"], newLines: ["end"], changeContext: undefined, endOfFile: true }],

},

])

})

test("rejects malformed hunk bodies", () => {

expect(() => Patch.parse("*** Begin Patch\n*** Add File: add.txt\nmissing plus\n*** End Patch")).toThrow(

"Invalid add file line",

)

expect(() => Patch.parse("*** Begin Patch\n*** Update File: update.txt\n*** End Patch")).toThrow(

"expected at least one @@ chunk",

)

expect(() => Patch.parse("*** Begin Patch\n*** Delete File: delete.txt\nunexpected body\n*** End Patch")).toThrow(

"Invalid patch line",

)

})

})