import { afterEach, beforeEach, describe, expect, mock, spyOn, test } from "bun:test"
import { resolveModelForDelegateTask } from "./model-selection"
import * as connectedProvidersCache from "../../shared/connected-providers-cache"

describe("resolveModelForDelegateTask", () => {
	let hasConnectedProvidersSpy: ReturnType<typeof spyOn> | undefined
	let hasProviderModelsSpy: ReturnType<typeof spyOn> | undefined

	beforeEach(() => {
		mock.restore()
	})

	afterEach(() => {
		hasConnectedProvidersSpy?.mockRestore()
		hasProviderModelsSpy?.mockRestore()
	})

	describe("#given no provider cache exists (pre-cache scenario)", () => {
		beforeEach(() => {
			hasConnectedProvidersSpy = spyOn(connectedProvidersCache, "hasConnectedProvidersCache").mockReturnValue(false)
			hasProviderModelsSpy = spyOn(connectedProvidersCache, "hasProviderModelsCache").mockReturnValue(false)
		})

		describe("#when availableModels is empty and no user model override", () => {
			test("#then returns undefined to let OpenCode use system default", () => {
				const result = resolveModelForDelegateTask({
					categoryDefaultModel: "anthropic/claude-sonnet-4-6",
					fallbackChain: [
						{ providers: ["anthropic"], model: "claude-sonnet-4-6" },
					],
					availableModels: new Set(),
					systemDefaultModel: "anthropic/claude-sonnet-4-6",
				})

				expect(result).toBeUndefined()
			})
		})

		describe("#when user explicitly set a model override", () => {
			test("#then returns the user model regardless of cache state", () => {
				const result = resolveModelForDelegateTask({
					userModel: "openai/gpt-5.4",
					categoryDefaultModel: "anthropic/claude-sonnet-4-6",
					fallbackChain: [
						{ providers: ["anthropic"], model: "claude-sonnet-4-6" },
					],
					availableModels: new Set(),
					systemDefaultModel: "anthropic/claude-sonnet-4-6",
				})

				expect(result).toEqual({ model: "openai/gpt-5.4" })
			})
		})

		describe("#when user set fallback_models but no cache exists", () => {
			test("#then returns undefined (skip fallback resolution without cache)", () => {
				const result = resolveModelForDelegateTask({
					userFallbackModels: ["openai/gpt-5.4", "google/gemini-3.1-pro"],
					categoryDefaultModel: "anthropic/claude-sonnet-4-6",
					fallbackChain: [
						{ providers: ["anthropic"], model: "claude-sonnet-4-6" },
					],
					availableModels: new Set(),
				})

				expect(result).toBeUndefined()
			})
		})
	})

	describe("#given provider cache exists", () => {
		beforeEach(() => {
			hasConnectedProvidersSpy = spyOn(connectedProvidersCache, "hasConnectedProvidersCache").mockReturnValue(true)
			hasProviderModelsSpy = spyOn(connectedProvidersCache, "hasProviderModelsCache").mockReturnValue(true)
		})

		describe("#when availableModels is empty (cache exists but empty)", () => {
			test("#then falls through to category default model (existing behavior)", () => {
				const result = resolveModelForDelegateTask({
					categoryDefaultModel: "anthropic/claude-sonnet-4-6",
					fallbackChain: [
						{ providers: ["anthropic"], model: "claude-sonnet-4-6" },
					],
					availableModels: new Set(),
					systemDefaultModel: "anthropic/claude-sonnet-4-6",
				})

				expect(result).toBeDefined()
				expect(result!.model).toBe("anthropic/claude-sonnet-4-6")
			})
		})

		describe("#when availableModels has entries and category default matches", () => {
			test("#then resolves via fuzzy match (existing behavior)", () => {
				const result = resolveModelForDelegateTask({
					categoryDefaultModel: "anthropic/claude-sonnet-4-6",
					fallbackChain: [
						{ providers: ["anthropic"], model: "claude-sonnet-4-6" },
					],
					availableModels: new Set(["anthropic/claude-sonnet-4-6"]),
				})

				expect(result).toBeDefined()
				expect(result!.model).toBe("anthropic/claude-sonnet-4-6")
			})
		})

		describe("#when user fallback models include variant syntax", () => {
			test("#then resolves a parenthesized variant against the base available model", () => {
				const result = resolveModelForDelegateTask({
					userFallbackModels: ["openai/gpt-5.2(high)"],
					availableModels: new Set(["openai/gpt-5.2"]),
				})

				expect(result).toEqual({ model: "openai/gpt-5.2", variant: "high" })
			})

			test("#then resolves a space-separated variant against the base available model", () => {
				const result = resolveModelForDelegateTask({
					userFallbackModels: ["gpt-5.2 medium"],
					availableModels: new Set(["openai/gpt-5.2"]),
				})

				expect(result).toEqual({ model: "openai/gpt-5.2", variant: "medium" })
			})
		})
	})

	describe("#given only connected providers cache exists (no provider-models cache)", () => {
		beforeEach(() => {
			hasConnectedProvidersSpy = spyOn(connectedProvidersCache, "hasConnectedProvidersCache").mockReturnValue(true)
			hasProviderModelsSpy = spyOn(connectedProvidersCache, "hasProviderModelsCache").mockReturnValue(false)
		})

		describe("#when availableModels is empty", () => {
			test("#then falls through to existing resolution (cache partially ready)", () => {
				const result = resolveModelForDelegateTask({
					categoryDefaultModel: "anthropic/claude-sonnet-4-6",
					fallbackChain: [
						{ providers: ["anthropic"], model: "claude-sonnet-4-6" },
					],
					availableModels: new Set(),
				})

				expect(result).toBeDefined()
			})
		})
	})
})