package llm

import (
	"context"
	"fmt"
	"io"
)

type Role string

const (
	RoleSystem    Role = "system"
	RoleUser      Role = "user"
	RoleAssistant Role = "assistant"
	RoleTool      Role = "tool"
)

type Message struct {
	Role       Role           `json:"role"`
	Content    string         `json:"content"`
	ToolCalls  []ToolCall     `json:"tool_calls,omitempty"`
	ToolCallID string         `json:"tool_call_id,omitempty"`
	Name       string         `json:"name,omitempty"`
	Images     []ImageContent `json:"images,omitempty"`
}

type ImageContent struct {
	Type     string `json:"type"`
	URL      string `json:"url,omitempty"`
	Data     string `json:"data,omitempty"`
	IsBase64 bool   `json:"isBase64,omitempty"`
}

type ToolCall struct {
	ID       string                 `json:"id"`
	Name     string                 `json:"name"`
	Arguments map[string]interface{} `json:"arguments"`
}

type Tool struct {
	Name        string      `json:"name"`
	Description string      `json:"description"`
	Schema      interface{} `json:"schema"`
}

type StreamOptions struct {
	MaxTokens   int     `json:"max_tokens,omitempty"`
	Temperature float64 `json:"temperature,omitempty"`
	TopP        float64 `json:"top_p,omitempty"`
	StopWords   []string `json:"stop,omitempty"`
}

type StreamChunk struct {
	ContentChunk  string     `json:"content_chunk,omitempty"`
	ToolCallChunk []ToolCall `json:"tool_call_chunk,omitempty"`
	FinishReason  string     `json:"finish_reason,omitempty"`
}

type StreamRequest struct {
	Messages []Message     `json:"messages"`
	Tools    []Tool        `json:"tools,omitempty"`
	Options  StreamOptions `json:"options,omitempty"`
}

type Client interface {
	StreamText(ctx context.Context, req StreamRequest) (<-chan StreamChunk, error)
	GenerateText(ctx context.Context, req StreamRequest) (string, error)
	GetProviderID() string
	GetModelKey() string
}

type ProviderConfig struct {
	ProviderID    string `json:"providerId"`
	ModelKey      string `json:"key"`
	APIKey        string `json:"apiKey,omitempty"`
	BaseURL       string `json:"baseUrl,omitempty"`
	AgentAccessID string `json:"agentAccessId,omitempty"`
}

func NewClient(cfg ProviderConfig) (Client, error) {
	switch cfg.ProviderID {
	case "timeweb":
		return NewTimewebClient(TimewebConfig{
			BaseURL:       cfg.BaseURL,
			AgentAccessID: cfg.AgentAccessID,
			APIKey:        cfg.APIKey,
			ModelKey:      cfg.ModelKey,
			ProxySource:   "gooseek",
		})
	case "openai":
		return NewOpenAIClient(cfg)
	case "anthropic":
		return NewAnthropicClient(cfg)
	case "gemini", "google":
		return NewGeminiClient(cfg)
	default:
		return nil, fmt.Errorf("unknown provider: %s", cfg.ProviderID)
	}
}

type baseClient struct {
	providerID string
	modelKey   string
}

func (c *baseClient) GetProviderID() string {
	return c.providerID
}

func (c *baseClient) GetModelKey() string {
	return c.modelKey
}

func readAllChunks(ch <-chan StreamChunk) string {
	var result string
	for chunk := range ch {
		result += chunk.ContentChunk
	}
	return result
}

type streamReader struct {
	ch     <-chan StreamChunk
	buffer []byte
}

func (r *streamReader) Read(p []byte) (n int, err error) {
	if len(r.buffer) > 0 {
		n = copy(p, r.buffer)
		r.buffer = r.buffer[n:]
		return n, nil
	}

	chunk, ok := <-r.ch
	if !ok {
		return 0, io.EOF
	}

	data := []byte(chunk.ContentChunk)
	n = copy(p, data)
	if n < len(data) {
		r.buffer = data[n:]
	}
	return n, nil
}