/**
 * 字体解析与真实度量测试（对应 §14 的"中文字体、长文本"测试）。
 *
 * 依赖系统字体，缺少字体时相关用例自动跳过，保证在无字体环境仍可运行。
 */
import { describe, expect, it } from "vitest"
import { existsSync } from "node:fs"
import { loadFontFile, FontLibrary, parseFontBuffer } from "../src/load-font.js"
import { createFontMeasurer } from "../src/font-measurer.js"
import { DEFAULT_RESOLVED_STYLE, type ResolvedStyle } from "@report/core"

const ARIAL = "C:\\Windows\\Fonts\\arial.ttf"
const SIMHEI = "C:\\Windows\\Fonts\\simhei.ttf"
const MSYH = "C:\\Windows\\Fonts\\msyh.ttc"

const hasArial = existsSync(ARIAL)
const hasSimHei = existsSync(SIMHEI)
const hasMsyh = existsSync(MSYH)

function style(overrides: Partial<ResolvedStyle> = {}): ResolvedStyle {
  return { ...DEFAULT_RESOLVED_STYLE, fontSize: 10, ...overrides }
}

describe("FontLibrary 加载", () => {
  it("加载失败时记录而不抛异常", () => {
    const library = new FontLibrary()
    const ok = library.load({ family: "Missing", path: "C:\\nope\\nope.ttf" })
    expect(ok).toBe(false)
    expect(library.loadFailures()).toHaveLength(1)
    expect(library.size).toBe(0)
  })

  it("clear 清空字体与失败记录", () => {
    const library = new FontLibrary()
    library.load({ family: "Missing", path: "C:\\nope\\nope.ttf" })
    library.clear()
    expect(library.size).toBe(0)
    expect(library.loadFailures()).toHaveLength(0)
  })
})

describe.skipIf(!hasArial)("Arial 度量", () => {
  const font = loadFontFile(ARIAL)

  it("解析出正确的字体元信息", () => {
    expect(font.metrics.familyName).toBe("Arial")
    expect(font.metrics.unitsPerEm).toBe(2048)
    expect(font.metrics.numGlyphs).toBeGreaterThan(1000)
  })

  it("比例字体的宽度各不相同", () => {
    const i = font.charAdvance("i".codePointAt(0)!)!
    const w = font.charAdvance("W".codePointAt(0)!)!
    expect(i).toBeLessThan(w)
    expect(i).toBeCloseTo(0.2222, 3)
    expect(w).toBeCloseTo(0.9438, 3)
  })

  it("不覆盖中文（返回 null 而非 .notdef 宽度）", () => {
    // 关键正确性检查：.notdef 本身有 advance，直接返回会把缺字当正常字符
    expect(font.hasGlyph("中".codePointAt(0)!)).toBe(false)
    expect(font.charAdvance("中".codePointAt(0)!)).toBeNull()
  })

  it("覆盖 ASCII", () => {
    for (const ch of ["A", "z", "0", " ", ".", ","]) {
      expect(font.hasGlyph(ch.codePointAt(0)!)).toBe(true)
    }
  })
})

describe.skipIf(!hasSimHei)("SimHei 中文字体度量", () => {
  const font = loadFontFile(SIMHEI)

  it("解析出中文字体族名", () => {
    expect(font.metrics.familyName).toBe("SimHei")
  })

  it("汉字宽度为全角 1.0 em", () => {
    for (const ch of ["中", "文", "报", "表"]) {
      expect(font.charAdvance(ch.codePointAt(0)!)).toBeCloseTo(1.0, 4)
    }
  })

  it("中文标点为全角", () => {
    expect(font.charAdvance("，".codePointAt(0)!)).toBeCloseTo(1.0, 4)
  })

  it("拉丁字符为半角", () => {
    expect(font.charAdvance("A".codePointAt(0)!)).toBeCloseTo(0.5, 4)
  })

  it("覆盖 GB 常用汉字", () => {
    for (const ch of ["销", "售", "单", "金", "额", "数", "量"]) {
      expect(font.hasGlyph(ch.codePointAt(0)!)).toBe(true)
    }
  })
})

describe.skipIf(!hasMsyh)("TTC 字体集合", () => {
  it("可从集合中按索引取字体", () => {
    const font0 = loadFontFile(MSYH, { fontIndex: 0 })
    expect(font0.metrics.unitsPerEm).toBeGreaterThan(0)
    expect(font0.metrics.familyName).toBeTruthy()
  })

  it("索引越界时报错", () => {
    expect(() => loadFontFile(MSYH, { fontIndex: 99 })).toThrow(/越界/)
  })
})

describe("parseFontBuffer 容错", () => {
  it("拒绝非字体数据", () => {
    const junk = Buffer.from("this is definitely not a font file")
    expect(() => parseFontBuffer(junk)).toThrow()
  })

  it("拒绝过短的数据", () => {
    expect(() => parseFontBuffer(Buffer.from([0, 1, 0, 0]))).toThrow()
  })
})

describe.skipIf(!hasArial || !hasSimHei)("字体库与度量器协作", () => {
  function buildLibrary(): FontLibrary {
    const library = new FontLibrary()
    library.load({ family: "Arial", path: ARIAL })
    library.load({ family: "SimHei", path: SIMHEI })
    return library
  }

  it("按字体栈解析", () => {
    const library = buildLibrary()
    const hit = library.resolveStack('"NoSuchFont", SimHei, sans-serif')
    expect(hit?.family).toBe("SimHei")
  })

  it("全部未命中时返回 undefined", () => {
    const library = buildLibrary()
    expect(library.resolveStack("NoSuchFont")).toBeUndefined()
  })

  it("度量纯英文文本", () => {
    const library = buildLibrary()
    const measurer = createFontMeasurer({ library })
    const metrics = measurer.measure("Hello", style({ fontFamily: "Arial", fontSize: 10 }))
    // 10pt 约 3.528mm；"Hello" 在 Arial 下约 2.6em
    expect(metrics.width).toBeGreaterThan(6)
    expect(metrics.width).toBeLessThan(12)
  })

  it("度量纯中文文本", () => {
    const library = buildLibrary()
    const measurer = createFontMeasurer({ library })
    const metrics = measurer.measure("中文报表", style({ fontFamily: "SimHei", fontSize: 10 }))
    const em = (10 / 72) * 25.4
    // 4 个全角字符 = 4em
    expect(metrics.width).toBeCloseTo(4 * em, 3)
  })

  it("中英混排按字符回退到 CJK 字体", () => {
    const library = buildLibrary()
    const fallbacks: string[] = []
    const measurer = createFontMeasurer({
      library,
      fallbackFamilies: ["SimHei"],
      onFallback: (e) => fallbacks.push(e.char),
    })
    const metrics = measurer.measure("A中", style({ fontFamily: "Arial", fontSize: 10 }))
    const em = (10 / 72) * 25.4
    // A(0.667) + 中(1.0) = 1.667em
    expect(metrics.width).toBeCloseTo(1.667 * em, 2)
    expect(fallbacks).toContain("中")
  })

  it("缺失字形提高 fallback 标记", () => {
    const library = buildLibrary()
    const measurer = createFontMeasurer({ library })
    // 用 Arial 度量汉字，且无 CJK 回退
    const metrics = measurer.measure("中", style({ fontFamily: "Arial" }))
    expect(metrics.fallback).toBe(true)
  })

  it("完整覆盖时 fallback 为 false", () => {
    const library = buildLibrary()
    const measurer = createFontMeasurer({ library })
    const metrics = measurer.measure("Hello", style({ fontFamily: "Arial" }))
    expect(metrics.fallback).toBe(false)
  })

  it("行高与字号成正比", () => {
    const library = buildLibrary()
    const measurer = createFontMeasurer({ library })
    const a = measurer.measure("x", style({ fontFamily: "Arial", fontSize: 10 }))
    const b = measurer.measure("x", style({ fontFamily: "Arial", fontSize: 20 }))
    expect(b.height).toBeCloseTo(a.height * 2, 4)
  })

  it("字体栈中首选命中时不回退", () => {
    const library = buildLibrary()
    const measurer = createFontMeasurer({ library, fallbackFamilies: ["SimHei"] })
    const resolved = measurer.resolver.resolve("Arial, SimHei")
    expect(resolved.resolved).toBe("Arial")
    expect(resolved.fallback).toBe(false)
  })

  it("字体栈全部未命中时标记回退", () => {
    const library = buildLibrary()
    const measurer = createFontMeasurer({ library })
    const resolved = measurer.resolver.resolve("Nonexistent")
    expect(resolved.fallback).toBe(true)
  })

  it("长文本宽度随字符数线性增长", () => {
    const library = buildLibrary()
    const measurer = createFontMeasurer({ library })
    const short = measurer.measure("中".repeat(10), style({ fontFamily: "SimHei" }))
    const long = measurer.measure("中".repeat(100), style({ fontFamily: "SimHei" }))
    expect(long.width).toBeCloseTo(short.width * 10, 3)
  })
})

describe("估算度量器（无字体环境）", () => {
  it("全角字符为 1em", async () => {
    const { createEstimateMeasurer } = await import("../src/measurer.js")
    const measurer = createEstimateMeasurer()
    const em = (10 / 72) * 25.4
    expect(measurer.measure("中", style()).width).toBeCloseTo(em, 4)
  })

  it("半角字符为 0.5em 附近", async () => {
    const { createEstimateMeasurer } = await import("../src/measurer.js")
    const measurer = createEstimateMeasurer()
    const em = (10 / 72) * 25.4
    const width = measurer.measure("n", style()).width
    expect(width).toBeGreaterThan(0.4 * em)
    expect(width).toBeLessThan(0.7 * em)
  })

  it("始终标记 fallback", async () => {
    const { createEstimateMeasurer } = await import("../src/measurer.js")
    expect(createEstimateMeasurer().measure("x", style()).fallback).toBe(true)
  })
})