package proxy

import "testing"

func TestComputeCost(t *testing.T) {
	// 标准三价：输入 0.5 / 输出 1.5 / 缓存读 0.05（$/M）
	const (
		inPrice  = 0.5
		outPrice = 1.5
		cchPrice = 0.05
	)

	tests := []struct {
		name          string
		upstreamProto string
		input         int
		output        int
		cacheRead     int
		cacheCreation int
		inP           float64
		outP          float64
		cchP          float64
		want          float64
	}{
		{
			// OpenAI：prompt 含缓存读，需扣减：(11000−10000)×0.5 + 10000×0.05 + 500×1.5
			name:          "openai prompt includes cache read",
			upstreamProto: "chat",
			input:         11000, output: 500, cacheRead: 10000,
			inP: inPrice, outP: outPrice, cchP: cchPrice,
			want: (1000*inPrice + 10000*cchPrice + 500*outPrice) / 1e6,
		},
		{
			// Anthropic：input 不含缓存；缓存写按输入价 ×1.25
			name:          "anthropic cache write at 1.25x input price",
			upstreamProto: "messages",
			input:         1000, output: 500, cacheRead: 10000, cacheCreation: 2000,
			inP: inPrice, outP: outPrice, cchP: cchPrice,
			want: (1000*inPrice + 10000*cchPrice + 2000*inPrice*1.25 + 500*outPrice) / 1e6,
		},
		{
			// Anthropic 口径不得扣减缓存读（否则这里非缓存输入会算成负数）
			name:          "anthropic does not subtract cache read",
			upstreamProto: "messages",
			input:         100, output: 0, cacheRead: 1000,
			inP: inPrice, outP: outPrice, cchP: cchPrice,
			want: (100*inPrice + 1000*cchPrice) / 1e6,
		},
		{
			// OpenAI 异常数据：cached > prompt 时非缓存输入钳制为 0，不出现负费用
			name:          "openai clamps negative uncached input",
			upstreamProto: "responses",
			input:         100, output: 0, cacheRead: 5000,
			inP: inPrice, outP: outPrice, cchP: cchPrice,
			want: (5000 * cchPrice) / 1e6,
		},
		{
			// 未配置价格时费用为 0
			name:          "no prices no cost",
			upstreamProto: "messages",
			input:         1000, output: 1000, cacheRead: 1000, cacheCreation: 1000,
			want: 0,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := ComputeCost(tt.upstreamProto, tt.input, tt.output, tt.cacheRead, tt.cacheCreation, tt.inP, tt.outP, tt.cchP)
			if diff := got - tt.want; diff > 1e-12 || diff < -1e-12 {
				t.Fatalf("ComputeCost(%q, in=%d, out=%d, cr=%d, cw=%d) = %v, want %v",
					tt.upstreamProto, tt.input, tt.output, tt.cacheRead, tt.cacheCreation, got, tt.want)
			}
		})
	}
}