package embeddings

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
)

// Config holds the settings for the Ollama embedder.
type Config struct {
	BaseURL string // e.g. "http://localhost:11434"
	Model   string // e.g. "nomic-embed-text"
}

// Ollama implements Embedder using Ollama's embedding API.
type Ollama struct {
	baseURL string
	model   string
	http    *http.Client
}

// NewOllama creates a new Ollama embedder.
func NewOllama(cfg Config) (*Ollama, error) {
	baseURL := cfg.BaseURL
	if baseURL == "" {
		baseURL = "http://localhost:11434"
	}
	model := cfg.Model
	if model == "" {
		model = "nomic-embed-text"
	}

	return &Ollama{
		baseURL: baseURL,
		model:   model,
		http:    http.DefaultClient,
	}, nil
}

func (e *Ollama) Embed(ctx context.Context, text string) ([]float32, error) {
	endpoint := e.baseURL + "/api/embed"

	reqBody, err := json.Marshal(map[string]interface{}{
		"model": e.model,
		"input": text,
	})
	if err != nil {
		return nil, fmt.Errorf("marshaling request: %w", err)
	}

	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, strings.NewReader(string(reqBody)))
	if err != nil {
		return nil, fmt.Errorf("creating request: %w", err)
	}
	httpReq.Header.Set("Content-Type", "application/json")

	resp, err := e.http.Do(httpReq)
	if err != nil {
		return nil, fmt.Errorf("request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		body, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("API error %d: %s", resp.StatusCode, string(body))
	}

	var apiResp ollamaEmbedResponse
	if err := json.NewDecoder(resp.Body).Decode(&apiResp); err != nil {
		return nil, fmt.Errorf("decoding response: %w", err)
	}

	return apiResp.Embedding, nil
}

func (e *Ollama) Dimensions() int {
	// Default for nomic-embed-text
	return 768
}

type ollamaEmbedResponse struct {
	Embedding []float32 `json:"embedding"`
}