// Package registry provides model definitions and lookup helpers for various AI providers.
// Static model metadata is loaded from the embedded models.json file and can be refreshed from network.
package registry

import (
	"sort"
	"strings"
)

// AntigravityModelConfig captures static antigravity model overrides, including
// Thinking budget limits and provider max completion tokens.
type AntigravityModelConfig struct {
	Thinking            *ThinkingSupport `json:"thinking,omitempty"`
	MaxCompletionTokens int              `json:"max_completion_tokens,omitempty"`
}

// staticModelsJSON mirrors the top-level structure of models.json.
type staticModelsJSON struct {
	Claude      []*ModelInfo                       `json:"claude"`
	Gemini      []*ModelInfo                       `json:"gemini"`
	Vertex      []*ModelInfo                       `json:"vertex"`
	GeminiCLI   []*ModelInfo                       `json:"gemini-cli"`
	AIStudio    []*ModelInfo                       `json:"aistudio"`
	CodexFree   []*ModelInfo                       `json:"codex-free"`
	CodexTeam   []*ModelInfo                       `json:"codex-team"`
	CodexPlus   []*ModelInfo                       `json:"codex-plus"`
	CodexPro    []*ModelInfo                       `json:"codex-pro"`
	Qwen        []*ModelInfo                       `json:"qwen"`
	IFlow       []*ModelInfo                       `json:"iflow"`
	Kimi        []*ModelInfo                       `json:"kimi"`
	Antigravity map[string]*AntigravityModelConfig `json:"antigravity"`
}

// GetClaudeModels returns the standard Claude model definitions.
func GetClaudeModels() []*ModelInfo {
	return cloneModelInfos(getModels().Claude)
}

// GetGeminiModels returns the standard Gemini model definitions.
func GetGeminiModels() []*ModelInfo {
	return cloneModelInfos(getModels().Gemini)
}

// GetGeminiVertexModels returns Gemini model definitions for Vertex AI.
func GetGeminiVertexModels() []*ModelInfo {
	return cloneModelInfos(getModels().Vertex)
}

// GetGeminiCLIModels returns Gemini model definitions for the Gemini CLI.
func GetGeminiCLIModels() []*ModelInfo {
	return cloneModelInfos(getModels().GeminiCLI)
}

// GetAIStudioModels returns model definitions for AI Studio.
func GetAIStudioModels() []*ModelInfo {
	return cloneModelInfos(getModels().AIStudio)
}

// GetCodexFreeModels returns model definitions for the Codex free plan tier.
func GetCodexFreeModels() []*ModelInfo {
	return cloneModelInfos(getModels().CodexFree)
}

// GetCodexTeamModels returns model definitions for the Codex team plan tier.
func GetCodexTeamModels() []*ModelInfo {
	return cloneModelInfos(getModels().CodexTeam)
}

// GetCodexPlusModels returns model definitions for the Codex plus plan tier.
func GetCodexPlusModels() []*ModelInfo {
	return cloneModelInfos(getModels().CodexPlus)
}

// GetCodexProModels returns model definitions for the Codex pro plan tier.
func GetCodexProModels() []*ModelInfo {
	return cloneModelInfos(getModels().CodexPro)
}

// GetQwenModels returns the standard Qwen model definitions.
func GetQwenModels() []*ModelInfo {
	return cloneModelInfos(getModels().Qwen)
}

// GetIFlowModels returns the standard iFlow model definitions.
func GetIFlowModels() []*ModelInfo {
	return cloneModelInfos(getModels().IFlow)
}

// GetKimiModels returns the standard Kimi (Moonshot AI) model definitions.
func GetKimiModels() []*ModelInfo {
	return cloneModelInfos(getModels().Kimi)
}

// GetAntigravityModelConfig returns static configuration for antigravity models.
// Keys use upstream model names returned by the Antigravity models endpoint.
func GetAntigravityModelConfig() map[string]*AntigravityModelConfig {
	data := getModels()
	if len(data.Antigravity) == 0 {
		return nil
	}
	out := make(map[string]*AntigravityModelConfig, len(data.Antigravity))
	for k, v := range data.Antigravity {
		out[k] = cloneAntigravityModelConfig(v)
	}
	return out
}

func cloneAntigravityModelConfig(cfg *AntigravityModelConfig) *AntigravityModelConfig {
	if cfg == nil {
		return nil
	}
	copyConfig := *cfg
	if cfg.Thinking != nil {
		copyThinking := *cfg.Thinking
		if len(cfg.Thinking.Levels) > 0 {
			copyThinking.Levels = append([]string(nil), cfg.Thinking.Levels...)
		}
		copyConfig.Thinking = &copyThinking
	}
	return &copyConfig
}

// cloneModelInfos returns a shallow copy of the slice with each element deep-cloned.
func cloneModelInfos(models []*ModelInfo) []*ModelInfo {
	if len(models) == 0 {
		return nil
	}
	out := make([]*ModelInfo, len(models))
	for i, m := range models {
		out[i] = cloneModelInfo(m)
	}
	return out
}

// GetStaticModelDefinitionsByChannel returns static model definitions for a given channel/provider.
// It returns nil when the channel is unknown.
//
// Supported channels:
//   - claude
//   - gemini
//   - vertex
//   - gemini-cli
//   - aistudio
//   - codex
//   - qwen
//   - iflow
//   - kimi
//   - antigravity (returns static overrides only)
func GetStaticModelDefinitionsByChannel(channel string) []*ModelInfo {
	key := strings.ToLower(strings.TrimSpace(channel))
	switch key {
	case "claude":
		return GetClaudeModels()
	case "gemini":
		return GetGeminiModels()
	case "vertex":
		return GetGeminiVertexModels()
	case "gemini-cli":
		return GetGeminiCLIModels()
	case "aistudio":
		return GetAIStudioModels()
	case "codex":
		return GetCodexProModels()
	case "qwen":
		return GetQwenModels()
	case "iflow":
		return GetIFlowModels()
	case "kimi":
		return GetKimiModels()
	case "antigravity":
		cfg := GetAntigravityModelConfig()
		if len(cfg) == 0 {
			return nil
		}
		models := make([]*ModelInfo, 0, len(cfg))
		for modelID, entry := range cfg {
			if modelID == "" || entry == nil {
				continue
			}
			models = append(models, &ModelInfo{
				ID:                  modelID,
				Object:              "model",
				OwnedBy:             "antigravity",
				Type:                "antigravity",
				Thinking:            entry.Thinking,
				MaxCompletionTokens: entry.MaxCompletionTokens,
			})
		}
		sort.Slice(models, func(i, j int) bool {
			return strings.ToLower(models[i].ID) < strings.ToLower(models[j].ID)
		})
		return models
	default:
		return nil
	}
}

// LookupStaticModelInfo searches all static model definitions for a model by ID.
// Returns nil if no matching model is found.
func LookupStaticModelInfo(modelID string) *ModelInfo {
	if modelID == "" {
		return nil
	}

	data := getModels()
	allModels := [][]*ModelInfo{
		data.Claude,
		data.Gemini,
		data.Vertex,
		data.GeminiCLI,
		data.AIStudio,
		data.CodexPro,
		data.Qwen,
		data.IFlow,
		data.Kimi,
	}
	for _, models := range allModels {
		for _, m := range models {
			if m != nil && m.ID == modelID {
				return cloneModelInfo(m)
			}
		}
	}

	// Check Antigravity static config
	if cfg := cloneAntigravityModelConfig(data.Antigravity[modelID]); cfg != nil {
		return &ModelInfo{
			ID:                  modelID,
			Thinking:            cfg.Thinking,
			MaxCompletionTokens: cfg.MaxCompletionTokens,
		}
	}

	return nil
}