package proxy

import (
	"encoding/json"
	"net/http"

	"github.com/gin-gonic/gin"
	"github.com/openteam/server/internal/store"
)

// chatCompletions POST /v1/chat/completions
func (g *Gateway) chatCompletions(c *gin.Context) {
	u, ok := g.resolveUser(c)
	if !ok {
		return
	}
	if !g.checkBalance(c, u) {
		return
	}

	br, body, err := parseBody(c)
	if err != nil {
		openAIError(c, http.StatusBadRequest, "invalid_request_error", "failed to read request body")
		return
	}
	c.Set("protocol", "chat")
	c.Set("model_name", br.Model)

	ch, err := g.ch.Select()
	if err != nil {
		openAIError(c, http.StatusServiceUnavailable, "no_channel", "No available upstream channel")
		g.recordError(c, nil, nil, now(), "no_channel")
		return
	}

	sink := &usageSink{}
	c.Set("usage_raw", &sinkHolder{sink: sink})
	g.doPassthrough(c, ch, "/v1/chat/completions", body, br.Stream, func(raw json.RawMessage) {
		sink.push(raw)
	})
}

// responses POST /v1/responses（OpenAI Responses API）
func (g *Gateway) responses(c *gin.Context) {
	u, ok := g.resolveUser(c)
	if !ok {
		return
	}
	if !g.checkBalance(c, u) {
		return
	}

	br, body, err := parseBody(c)
	if err != nil {
		openAIError(c, http.StatusBadRequest, "invalid_request_error", "failed to read request body")
		return
	}
	c.Set("protocol", "responses")
	c.Set("model_name", br.Model)

	ch, err := g.ch.Select()
	if err != nil {
		openAIError(c, http.StatusServiceUnavailable, "no_channel", "No available upstream channel")
		g.recordError(c, nil, nil, now(), "no_channel")
		return
	}
	// M1 仅支持 OpenAI 原生渠道直通；Anthropic 渠道的转换在 M3
	if ch.Provider != store.ChannelProviderOpenAI {
		openAIError(c, http.StatusNotImplemented, "conversion_pending",
			"Responses protocol on this channel requires format conversion (planned in M3)")
		return
	}

	sink := &usageSink{}
	c.Set("usage_raw", &sinkHolder{sink: sink})
	g.doPassthrough(c, ch, "/v1/responses", body, br.Stream, func(raw json.RawMessage) {
		sink.push(raw)
	})
}

// usageSinkHolder 桥接：gin context 里保存 sink 引用，供 finishUsage 读取最终 usage。
type sinkHolder struct {
	sink *usageSink
}

// openAIError 按 OpenAI 错误格式返回（PLANNING §4.1.4）。
func openAIError(c *gin.Context, status int, code, message string) {
	c.AbortWithStatusJSON(status, gin.H{
		"error": gin.H{
			"message": message,
			"type":    errorTypeFor(status),
			"param":   nil,
			"code":    code,
		},
	})
}

func errorTypeFor(status int) string {
	switch status {
	case http.StatusUnauthorized:
		return "authentication_error"
	case http.StatusForbidden:
		return "permission_error"
	case http.StatusNotFound:
		return "invalid_request_error"
	case http.StatusBadRequest:
		return "invalid_request_error"
	case http.StatusPaymentRequired:
		return "insufficient_quota"
	case http.StatusTooManyRequests:
		return "rate_limit_error"
	default:
		return "api_error"
	}
}