package proxy

// ZenBaseURL is the upstream OpenCode Zen API base URL.
const ZenBaseURL = "https://opencode.ai/zen/v1"

// OpenCodeBackend forwards to OpenCode's free Zen models.
type OpenCodeBackend struct{}

// zenModels are the free models exposed by OpenCode Zen (no API key required).
var zenModels = []ModelInfo{
	{
		ID:              "big-pickle",
		Name:            "Big Pickle (Free)",
		OwnedBy:         "opencode-zen",
		ContextWindow:   200_000,
		MaxOutputTokens: 32_000,
		Description:     "Permanentemente gratis. Código legacy, refactors, mantenimiento.",
	},
	{
		ID:              "deepseek-v4-flash-free",
		Name:            "DeepSeek V4 Flash (Free)",
		OwnedBy:         "deepseek",
		ContextWindow:   1_000_000,
		MaxOutputTokens: 384_000,
		Description:     "El todoterreno. 1M contexto, 284B params (13B activos), razonamiento.",
	},
	{
		ID:              "mimo-v2.5-free",
		Name:            "MiMo V2.5 (Free)",
		OwnedBy:         "xiaomi",
		ContextWindow:   1_000_000,
		MaxOutputTokens: 32_000,
		Description:     "Multimodal de Xiaomi. 1M contexto, imágenes → código. MIT license.",
		SupportsVision:  true,
	},
	{
		ID:              "north-mini-code-free",
		Name:            "North Mini Code (Free)",
		OwnedBy:         "cohere",
		ContextWindow:   256_000,
		MaxOutputTokens: 64_000,
		Description:     "Cohere. 30B total / 3B activos (MoE). Respuesta rápida, scripts.",
	},
	{
		ID:              "nemotron-3-ultra-free",
		Name:            "Nemotron 3 Ultra (Free)",
		OwnedBy:         "nvidia",
		ContextWindow:   1_000_000,
		MaxOutputTokens: 16_384,
		Description:     "NVIDIA. 550B params (55B activos). Mamba-2 + MoE híbrido. Razonamiento.",
	},
}

// modelAliases maps short/company/Claude names to OpenCode Zen model IDs.
var modelAliases = map[string]string{
	// Short aliases
	"pickle":       "big-pickle",
	"big-pickle":   "big-pickle",
	"deepseek":     "deepseek-v4-flash-free",
	"deepseek-v4":  "deepseek-v4-flash-free",
	"ds":           "deepseek-v4-flash-free",
	"mimo":         "mimo-v2.5-free",
	"mimo-v2.5":    "mimo-v2.5-free",
	"xiaomi":       "mimo-v2.5-free",
	"north":        "north-mini-code-free",
	"north-mini":   "north-mini-code-free",
	"cohere":       "north-mini-code-free",
	"nemotron":     "nemotron-3-ultra-free",
	"nemotron-3":   "nemotron-3-ultra-free",
	"nvidia":       "nemotron-3-ultra-free",
	// Exact IDs
	"deepseek-v4-flash-free": "deepseek-v4-flash-free",
	"mimo-v2.5-free":         "mimo-v2.5-free",
	"north-mini-code-free":   "north-mini-code-free",
	"nemotron-3-ultra-free":  "nemotron-3-ultra-free",

	// Claude model name aliases (Claude Code validates model names client-side).
	"claude-sonnet-4-6": "deepseek-v4-flash-free",
	"claude-sonnet-4-5": "deepseek-v4-flash-free",
	"claude-sonnet-4":   "deepseek-v4-flash-free",
	"claude-opus-4-8":   "deepseek-v4-flash-free",
	"claude-opus-4-5":   "deepseek-v4-flash-free",
	"claude-opus-4":     "deepseek-v4-flash-free",
	"claude-haiku-4-5":  "north-mini-code-free",
	"claude-haiku-4":    "north-mini-code-free",
	"claude-3.5-sonnet": "north-mini-code-free",
	"claude-3.5-haiku":  "big-pickle",
}

// Name returns the backend identifier.
func (OpenCodeBackend) Name() string { return "opencode" }

// Models returns the OpenCode Zen free models.
func (OpenCodeBackend) Models() []ModelInfo { return zenModels }

// Resolve maps a requested name to an OpenCode Zen model ID.
func (OpenCodeBackend) Resolve(model string) (string, bool) {
	if mapped, ok := modelAliases[model]; ok {
		return mapped, true
	}
	for _, m := range zenModels {
		if m.ID == model {
			return model, true
		}
	}
	return "", false
}

// ChatURL is the OpenCode Zen chat completions endpoint.
func (OpenCodeBackend) ChatURL() string { return ZenBaseURL + "/chat/completions" }

// Headers builds the headers OpenCode Zen expects (x-opencode-* + public bearer).
func (OpenCodeBackend) Headers(requestID, sessionID string) map[string]string {
	return map[string]string{
		"Authorization":      "Bearer public",
		"User-Agent":         "opencode/1.15.0 ai-sdk/provider-utils/4.0.23 runtime/bun/1.3.13",
		"x-opencode-client":  "cli",
		"x-opencode-project": "global",
		"x-opencode-request": requestID,
		"x-opencode-session": sessionID,
		"Content-Type":       "application/json",
		"Accept":             "text/event-stream, application/json",
	}
}

// ModelByID returns the OpenCode Zen ModelInfo for an ID, or nil if not found.
// Used by the Anthropic path for vision auto-routing.
func ModelByID(id string) *ModelInfo {
	for _, m := range zenModels {
		if m.ID == id {
			return &m
		}
	}
	return nil
}

// ZenChatURL returns the OpenCode Zen chat completions URL.
// Kept for backwards compatibility with existing call sites.
func ZenChatURL() string { return ZenBaseURL + "/chat/completions" }

// ZenModelsURL returns the OpenCode Zen models listing URL.
func ZenModelsURL() string { return ZenBaseURL + "/models" }