import { describe, expect, test } from "bun:test"
import path from "path"
import { SessionCompaction } from "../../src/session/compaction"
import { Token } from "../../src/util/token"
import { Instance } from "../../src/project/instance"
import { Log } from "../../src/util/log"
import { tmpdir } from "../fixture/fixture"
import { Session } from "../../src/session"
import type { Provider } from "../../src/provider/provider"

Log.init({ print: false })

function createModel(opts: { context: number; output: number; cost?: Provider.Model["cost"] }): Provider.Model {
  return {
    id: "test-model",
    providerID: "test",
    name: "Test",
    limit: {
      context: opts.context,
      output: opts.output,
    },
    cost: opts.cost ?? { input: 0, output: 0, cache: { read: 0, write: 0 } },
    capabilities: {
      toolcall: true,
      attachment: false,
      reasoning: false,
      temperature: true,
      input: { text: true, image: false, audio: false, video: false },
      output: { text: true, image: false, audio: false, video: false },
    },
    api: { npm: "@ai-sdk/anthropic" },
    options: {},
  } as Provider.Model
}

describe("session.compaction.isOverflow", () => {
  test("returns true when token count exceeds usable context", async () => {
    await using tmp = await tmpdir()
    await Instance.provide({
      directory: tmp.path,
      fn: async () => {
        const model = createModel({ context: 100_000, output: 32_000 })
        const tokens = { input: 75_000, output: 5_000, reasoning: 0, cache: { read: 0, write: 0 } }
        expect(await SessionCompaction.isOverflow({ tokens, model })).toBe(true)
      },
    })
  })

  test("returns false when token count within usable context", async () => {
    await using tmp = await tmpdir()
    await Instance.provide({
      directory: tmp.path,
      fn: async () => {
        const model = createModel({ context: 200_000, output: 32_000 })
        const tokens = { input: 100_000, output: 10_000, reasoning: 0, cache: { read: 0, write: 0 } }
        expect(await SessionCompaction.isOverflow({ tokens, model })).toBe(false)
      },
    })
  })

  test("includes cache.read in token count", async () => {
    await using tmp = await tmpdir()
    await Instance.provide({
      directory: tmp.path,
      fn: async () => {
        const model = createModel({ context: 100_000, output: 32_000 })
        const tokens = { input: 50_000, output: 10_000, reasoning: 0, cache: { read: 10_000, write: 0 } }
        expect(await SessionCompaction.isOverflow({ tokens, model })).toBe(true)
      },
    })
  })

  test("returns false when model context limit is 0", async () => {
    await using tmp = await tmpdir()
    await Instance.provide({
      directory: tmp.path,
      fn: async () => {
        const model = createModel({ context: 0, output: 32_000 })
        const tokens = { input: 100_000, output: 10_000, reasoning: 0, cache: { read: 0, write: 0 } }
        expect(await SessionCompaction.isOverflow({ tokens, model })).toBe(false)
      },
    })
  })

  test("returns false when compaction.auto is disabled", async () => {
    await using tmp = await tmpdir({
      init: async (dir) => {
        await Bun.write(
          path.join(dir, "opencode.json"),
          JSON.stringify({
            compaction: { auto: false },
          }),
        )
      },
    })
    await Instance.provide({
      directory: tmp.path,
      fn: async () => {
        const model = createModel({ context: 100_000, output: 32_000 })
        const tokens = { input: 75_000, output: 5_000, reasoning: 0, cache: { read: 0, write: 0 } }
        expect(await SessionCompaction.isOverflow({ tokens, model })).toBe(false)
      },
    })
  })
})

describe("util.token.estimate", () => {
  test("estimates tokens from text (4 chars per token)", () => {
    const text = "x".repeat(4000)
    expect(Token.estimate(text)).toBe(1000)
  })

  test("estimates tokens from larger text", () => {
    const text = "y".repeat(20_000)
    expect(Token.estimate(text)).toBe(5000)
  })

  test("returns 0 for empty string", () => {
    expect(Token.estimate("")).toBe(0)
  })
})

describe("session.getUsage", () => {
  test("normalizes standard usage to token format", () => {
    const model = createModel({ context: 100_000, output: 32_000 })
    const result = Session.getUsage({
      model,
      usage: {
        inputTokens: 1000,
        outputTokens: 500,
        totalTokens: 1500,
      },
    })

    expect(result.tokens.input).toBe(1000)
    expect(result.tokens.output).toBe(500)
    expect(result.tokens.reasoning).toBe(0)
    expect(result.tokens.cache.read).toBe(0)
    expect(result.tokens.cache.write).toBe(0)
  })

  test("extracts cached tokens to cache.read", () => {
    const model = createModel({ context: 100_000, output: 32_000 })
    const result = Session.getUsage({
      model,
      usage: {
        inputTokens: 1000,
        outputTokens: 500,
        totalTokens: 1500,
        cachedInputTokens: 200,
      },
    })

    expect(result.tokens.input).toBe(800)
    expect(result.tokens.cache.read).toBe(200)
  })

  test("handles anthropic cache write metadata", () => {
    const model = createModel({ context: 100_000, output: 32_000 })
    const result = Session.getUsage({
      model,
      usage: {
        inputTokens: 1000,
        outputTokens: 500,
        totalTokens: 1500,
      },
      metadata: {
        anthropic: {
          cacheCreationInputTokens: 300,
        },
      },
    })

    expect(result.tokens.cache.write).toBe(300)
  })

  test("does not subtract cached tokens for anthropic provider", () => {
    const model = createModel({ context: 100_000, output: 32_000 })
    const result = Session.getUsage({
      model,
      usage: {
        inputTokens: 1000,
        outputTokens: 500,
        totalTokens: 1500,
        cachedInputTokens: 200,
      },
      metadata: {
        anthropic: {},
      },
    })

    expect(result.tokens.input).toBe(1000)
    expect(result.tokens.cache.read).toBe(200)
  })

  test("handles reasoning tokens", () => {
    const model = createModel({ context: 100_000, output: 32_000 })
    const result = Session.getUsage({
      model,
      usage: {
        inputTokens: 1000,
        outputTokens: 500,
        totalTokens: 1500,
        reasoningTokens: 100,
      },
    })

    expect(result.tokens.reasoning).toBe(100)
  })

  test("handles undefined optional values gracefully", () => {
    const model = createModel({ context: 100_000, output: 32_000 })
    const result = Session.getUsage({
      model,
      usage: {
        inputTokens: 0,
        outputTokens: 0,
        totalTokens: 0,
      },
    })

    expect(result.tokens.input).toBe(0)
    expect(result.tokens.output).toBe(0)
    expect(result.tokens.reasoning).toBe(0)
    expect(result.tokens.cache.read).toBe(0)
    expect(result.tokens.cache.write).toBe(0)
    expect(Number.isNaN(result.cost)).toBe(false)
  })

  test("calculates cost correctly", () => {
    const model = createModel({
      context: 100_000,
      output: 32_000,
      cost: {
        input: 3,
        output: 15,
        cache: { read: 0.3, write: 3.75 },
      },
    })
    const result = Session.getUsage({
      model,
      usage: {
        inputTokens: 1_000_000,
        outputTokens: 100_000,
        totalTokens: 1_100_000,
      },
    })

    expect(result.cost).toBe(3 + 1.5)
  })
})