package llm

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

// ListModels returns available models from the LLM server.
func (c *Client) ListModels(ctx context.Context) ([]Model, error) {
	ctx, cancel := context.WithTimeout(ctx, c.timeout)
	defer cancel()

	req, err := http.NewRequestWithContext(
		ctx, http.MethodGet, c.baseURL+"/models", nil,
	)
	if err != nil {
		return nil, fmt.Errorf("create request: %w", err)
	}
	if c.key != "" {
		req.Header.Set("Authorization", "Bearer "+c.key)
	}
	req.Header.Set("Content-Type", "application/json")

	res, err := c.httpc.Do(req)
	if err != nil {
		return nil, fmt.Errorf("list models: %w", err)
	}
	defer res.Body.Close()

	if res.StatusCode != http.StatusOK {
		body, err := io.ReadAll(res.Body)
		if err != nil {
			c.log.ErrorContext(
				ctx,
				"list models: failed to read error response body",
				slog.Any("error", err),
			)
			return nil, fmt.Errorf(
				"list models: status code %d", res.StatusCode,
			)
		}
		var apiError struct {
			Error *struct {
				Type    string `json:"type"`
				Code    string `json:"code"`
				Message string `json:"message"`
			} `json:"error"`
		}
		if err := json.Unmarshal(
			body, &apiError,
		); err == nil && apiError.Error != nil {
			c.log.ErrorContext(
				ctx,
				"list models: request error",
				slog.Int("status", res.StatusCode),
				slog.String("code", apiError.Error.Code),
				slog.String(
					"message", apiError.Error.Message,
				),
				slog.String("type", apiError.Error.Type),
			)
			return nil, fmt.Errorf(
				"list models: %s: %s",
				apiError.Error.Code,
				apiError.Error.Message,
			)
		}
		c.log.ErrorContext(
			ctx,
			"list models: API error",
			slog.Int("status", res.StatusCode),
			slog.String("body", string(body)),
		)
		return nil, fmt.Errorf(
			"list models: %d: %s",
			res.StatusCode, string(body),
		)
	}

	var body ModelsResponse
	if err := json.NewDecoder(res.Body).Decode(&body); err != nil {
		return nil, fmt.Errorf(
			"list models: decode response: %w", err,
		)
	}

	return body.Data, nil
}