package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"image"
	"io"
	"net/http"
	"strconv"
	"strings"

	"git.kornbrand.biz/plankalkul/autoixpert-sample/pkg/models"
)

type apiError struct {
	StatusCode   int    `json:"status_code"`
	Endpoint     string `json:"endpoint"`
	ErrorCode    string `json:"error_code"`
	ErrorMessage string `json:"error_message"`
	StackTrace   string `json:"stack_trace"`
}

// could be more elaborate depending on the users needs, for simplicity just the API error messageu
// depending on usecase, might be useful to include all fields of this in the slog as parsebable output
func (e *apiError) Error() string {
	if e.ErrorMessage == "" {
		return fmt.Sprintf("api request: %s failed with status %d", e.Endpoint, e.StatusCode)
	}
	return e.ErrorMessage
}

func decodeAPIError(resp *http.Response) error {
	body, readErr := io.ReadAll(resp.Body)
	if readErr != nil {
		return fmt.Errorf("api request failed with status %d (failed to read error response: %w)", resp.StatusCode, readErr)
	}

	var apiErr apiError
	if err := json.Unmarshal(body, &apiErr); err != nil {
		return fmt.Errorf("api request failed with status %d (failed to decode error response: %w)", resp.StatusCode, err)
	}

	return &apiErr
}

func createReport(report models.CrashReport) (string, error) {

	var body = report.ToClaimRequest()
	data, err := json.Marshal(body)
	if err != nil {
		return "", err
	}

	req, err := http.NewRequest("POST", cfg.APIBase+"/reports", bytes.NewBuffer(data))
	if err != nil {
		return "", err
	}
	req.Header.Set("Authorization", "Bearer "+cfg.APIKey)
	req.Header.Set("Content-Type", "application/json")

	resp, err := DoWithRateLimitReset(context.Background(), req)

	if err != nil {
		return "", err
	}

	defer resp.Body.Close()
	if resp.StatusCode >= 400 {
		return "", decodeAPIError(resp)
	}

	var claimResp models.ClaimResponse
	if err := json.NewDecoder(resp.Body).Decode(&claimResp); err != nil {
		return "", err
	}

	return claimResp.Document.ID, nil
}

func uploadImages(imageURLs []string, id string, eventID string) error {
	images, err := collectImages(imageURLs)
	if err != nil {
		return err
	}

	metaResp, err := requestPhotoMetadata(id, eventID, images)
	if err != nil {
		return err
	}

	uploadResp, err := requestUploadURLs(id, eventID, metaResp)
	if err != nil {
		return err
	}

	return uploadPhotoBinaries(images, metaResp, uploadResp)
}

func collectImages(imageURLs []string) ([]imageWithMeta, error) {
	images := make([]imageWithMeta, 0, len(imageURLs))

	for idx, url := range imageURLs {
		resp, err := http.Get(url)
		if err != nil {
			return nil, err
		}

		data, err := io.ReadAll(resp.Body)
		_ = resp.Body.Close()
		if err != nil {
			return nil, err
		}

		mime := http.DetectContentType(data)
		size := len(data)
		cfg, _, err := image.DecodeConfig(bytes.NewReader(data))
		if err != nil {
			return nil, err
		}

		images = append(images, imageWithMeta{
			Data: data,
			Meta: models.ImageMetaRequest{
				Title:            strconv.Itoa(idx),
				Description:      "",
				OriginalName:     strconv.Itoa(idx),
				Mimetype:         mime,
				Size:             int64(size),
				Width:            cfg.Width,
				Height:           cfg.Height,
				IncludedInReport: true,
			},
		})
	}

	return images, nil
}

func requestPhotoMetadata(reportID string, eventID string, images []imageWithMeta) (models.ImageMetaResponse, error) {
	metas := make([]models.ImageMetaRequest, 0, len(images))
	for _, img := range images {
		metas = append(metas, img.Meta)
	}

	body, err := json.Marshal(models.ImageMetaRequestWrapper{Photos: metas})
	if err != nil {
		return models.ImageMetaResponse{}, err
	}

	req, err := http.NewRequest("POST", cfg.APIBase+"/reports/"+reportID+"/photos/batch", bytes.NewBuffer(body))
	if err != nil {
		return models.ImageMetaResponse{}, err
	}
	req.Header.Set("Authorization", "Bearer "+cfg.APIKey)
	req.Header.Set("Content-Type", "application/json")

	resp, err := DoWithRateLimitReset(context.Background(), req)
	if err != nil {
		return models.ImageMetaResponse{}, err
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 400 {
		return models.ImageMetaResponse{}, decodeAPIError(resp)
	}

	var metaResp models.ImageMetaResponse
	if err := json.NewDecoder(resp.Body).Decode(&metaResp); err != nil {
		return models.ImageMetaResponse{}, err
	}

	return metaResp, nil
}

func requestUploadURLs(reportID string, eventID string, metaResp models.ImageMetaResponse) (models.UploadURLResponse, error) {
	ids := make([]string, 0, len(metaResp.Photos))
	for _, photo := range metaResp.Photos {
		ids = append(ids, photo.ID)
	}

	req, err := http.NewRequest("GET", cfg.APIBase+"/reports/"+reportID+"/photos/batch/upload?photo_ids="+strings.Join(ids, ","), nil)
	if err != nil {
		return models.UploadURLResponse{}, err
	}
	req.Header.Set("Authorization", "Bearer "+cfg.APIKey)
	req.Header.Set("Content-Type", "application/json")

	resp, err := DoWithRateLimitReset(context.Background(), req)
	if err != nil {
		return models.UploadURLResponse{}, err
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 400 {
		return models.UploadURLResponse{}, decodeAPIError(resp)
	}

	var uploadResp models.UploadURLResponse
	if err := json.NewDecoder(resp.Body).Decode(&uploadResp); err != nil {
		return models.UploadURLResponse{}, err
	}

	return uploadResp, nil
}

func uploadPhotoBinaries(images []imageWithMeta, metaResp models.ImageMetaResponse, uploadResp models.UploadURLResponse) error {
	imageByTitle := make(map[string]imageWithMeta, len(images))
	for _, img := range images {
		imageByTitle[img.Meta.Title] = img
	}

	titleByPhotoID := make(map[string]string, len(metaResp.Photos))
	for _, metaImg := range metaResp.Photos {
		titleByPhotoID[metaImg.ID] = metaImg.Title
	}

	for _, upload := range uploadResp.UploadURLs {
		title, ok := titleByPhotoID[upload.PhotoID]
		if !ok {
			continue
		}

		img, ok := imageByTitle[title]
		if !ok {
			continue
		}

		putReq, err := http.NewRequest("PUT", upload.UploadURL, bytes.NewReader(img.Data))
		if err != nil {
			return err
		}
		putReq.Header.Set("Content-Type", img.Meta.Mimetype)

		resp, err := Do(context.Background(), putReq)
		if err != nil {
			return err
		}

		defer resp.Body.Close()

		if resp.StatusCode >= 400 {
			return fmt.Errorf("failed to upload photo %s: status %d", title, resp.StatusCode)
		}

	}

	return nil
}