package prompts

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/postmet/transcribe/internal/models"
)

type Loader struct {
	source    string
	filePath  string
	baseURL   string
	apiKey    string
	sectionID int
	client    *http.Client
}

func New(source, filePath, baseURL, apiKey string, sectionID int) *Loader {
	return &Loader{
		source:    source,
		filePath:  filePath,
		baseURL:   strings.TrimRight(baseURL, "/"),
		apiKey:    apiKey,
		sectionID: sectionID,
		client:    &http.Client{Timeout: 30 * time.Second},
	}
}

func (l *Loader) Load(ctx context.Context) ([]models.Prompt, error) {
	switch strings.ToLower(l.source) {
	case "http":
		return l.loadHTTP(ctx)
	default:
		return l.loadStatic()
	}
}

func (l *Loader) loadStatic() ([]models.Prompt, error) {
	data, err := os.ReadFile(l.filePath)
	if err != nil {
		return nil, fmt.Errorf("read prompts file: %w", err)
	}
	var prompts []models.Prompt
	if err := json.Unmarshal(data, &prompts); err != nil {
		return nil, fmt.Errorf("parse prompts file: %w", err)
	}
	return filterSection(prompts, l.sectionID), nil
}

func (l *Loader) loadHTTP(ctx context.Context) ([]models.Prompt, error) {
	if l.baseURL == "" {
		return nil, fmt.Errorf("PROMPTS_BASE_URL is required for http source")
	}
	url := fmt.Sprintf("%s/metrics/?id_section=%s", l.baseURL, strconv.Itoa(l.sectionID))
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		return nil, err
	}
	if l.apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+l.apiKey)
	}
	resp, err := l.client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("prompts api status %d: %s", resp.StatusCode, string(body))
	}
	var prompts []models.Prompt
	if err := json.Unmarshal(body, &prompts); err != nil {
		return nil, fmt.Errorf("parse prompts response: %w", err)
	}
	return filterSection(prompts, l.sectionID), nil
}

func filterSection(prompts []models.Prompt, sectionID int) []models.Prompt {
	if sectionID <= 0 {
		return prompts
	}
	out := make([]models.Prompt, 0, len(prompts))
	for _, p := range prompts {
		if p.IDSection == sectionID {
			out = append(out, p)
		}
	}
	return out
}