package handlers

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"fred-api/config"
	"fred-api/models"

	"github.com/gin-gonic/gin"
)

type FREDHandler struct {
	baseURL string
	apiKey  string
}

func NewFREDHandler(cfg *config.Config) *FREDHandler {
	return &FREDHandler{
		baseURL: cfg.FREDBaseURL,
		apiKey:  cfg.FREDAPIKey,
	}
}

func (h *FREDHandler) buildURL(endpoint string, params map[string]string) string {
	u, _ := url.Parse(h.baseURL + endpoint)
	query := u.Query()
	query.Set("api_key", h.apiKey)
	query.Set("file_type", "json")

	for k, v := range params {
		if v != "" {
			query.Set(k, v)
		}
	}

	u.RawQuery = query.Encode()
	return u.String()
}

func (h *FREDHandler) fetchData(target interface{}, c *gin.Context, endpoint string, params map[string]string) {
	url := h.buildURL(endpoint, params)

	resp, err := http.Get(url)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			ErrorCode:    "NetworkError",
			ErrorMessage: err.Error(),
		})
		return
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			ErrorCode:    "ReadError",
			ErrorMessage: err.Error(),
		})
		return
	}

	if resp.StatusCode != http.StatusOK {
		var errResp models.ErrorResponse
		json.Unmarshal(body, &errResp)
		c.JSON(http.StatusBadGateway, models.ErrorResponse{
			ErrorCode:    "APIError",
			ErrorMessage: fmt.Sprintf("Status: %d, Error: %s - %s", resp.StatusCode, errResp.ErrorCode, errResp.ErrorMessage),
		})
		return
	}

	if err := json.Unmarshal(body, target); err != nil {
		c.JSON(http.StatusInternalServerError, models.ErrorResponse{
			ErrorCode:    "ParseError",
			ErrorMessage: err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, target)
}

func (h *FREDHandler) HealthCheck(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{
		"status":  "healthy",
		"service": "FRED API",
	})
}

func (h *FREDHandler) GetCategory(c *gin.Context) {
	categoryID := c.Query("category_id")
	if categoryID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "category_id is required",
		})
		return
	}
	h.fetchData(&models.CategoryResponse{}, c, "/category", map[string]string{"category_id": categoryID})
}

func (h *FREDHandler) GetCategoryChildren(c *gin.Context) {
	categoryID := c.Query("category_id")
	if categoryID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "category_id is required",
		})
		return
	}
	params := map[string]string{"category_id": categoryID}
	h.fetchData(&models.CategoriesResponse{}, c, "/category/children", params)
}

func (h *FREDHandler) GetCategoryRelated(c *gin.Context) {
	categoryID := c.Query("category_id")
	if categoryID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "category_id is required",
		})
		return
	}
	h.fetchData(&models.RelatedTagsResponse{}, c, "/category/related", map[string]string{"category_id": categoryID})
}

func (h *FREDHandler) GetCategorySeries(c *gin.Context) {
	categoryID := c.Query("category_id")
	if categoryID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "category_id is required",
		})
		return
	}
	params := map[string]string{"category_id": categoryID}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order"})
	h.fetchData(&models.CategorySeriesResponse{}, c, "/category/series", params)
}

func (h *FREDHandler) GetCategoryTags(c *gin.Context) {
	categoryID := c.Query("category_id")
	if categoryID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "category_id is required",
		})
		return
	}
	params := map[string]string{"category_id": categoryID}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order"})
	h.fetchData(&models.CategoryTagsResponse{}, c, "/category/tags", params)
}

func (h *FREDHandler) GetCategoryRelatedTags(c *gin.Context) {
	categoryID := c.Query("category_id")
	if categoryID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "category_id is required",
		})
		return
	}
	tagNames := c.Query("tag_names")
	if tagNames == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "tag_names is required",
		})
		return
	}
	params := map[string]string{"category_id": categoryID, "tag_names": tagNames}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order"})
	h.fetchData(&models.RelatedTagsResponse{}, c, "/category/related_tags", params)
}

func (h *FREDHandler) GetSeries(c *gin.Context) {
	seriesID := c.Query("series_id")
	if seriesID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "series_id is required",
		})
		return
	}
	params := map[string]string{"series_id": seriesID}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end"})
	h.fetchData(&models.SeriesResponse{}, c, "/series", params)
}

func (h *FREDHandler) GetSeriesCategories(c *gin.Context) {
	seriesID := c.Query("series_id")
	if seriesID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "series_id is required",
		})
		return
	}
	params := map[string]string{"series_id": seriesID}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end"})
	h.fetchData(&models.SeriesCategoriesResponse{}, c, "/series/categories", params)
}

func (h *FREDHandler) GetObservations(c *gin.Context) {
	seriesID := c.Query("series_id")
	if seriesID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "series_id is required",
		})
		return
	}
	params := map[string]string{"series_id": seriesID}
	h.addOptionalParams(c, params, []string{
		"realtime_start", "realtime_end", "limit", "offset", "sort_order",
		"observation_start", "observation_end", "units", "frequency",
		"aggregation_method", "output_type", "vintage_dates",
	})
	h.fetchData(&models.ObservationsResponse{}, c, "/series/observations", params)
}

func (h *FREDHandler) GetSeriesRelease(c *gin.Context) {
	seriesID := c.Query("series_id")
	if seriesID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "series_id is required",
		})
		return
	}
	params := map[string]string{"series_id": seriesID}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end"})
	h.fetchData(&models.ReleaseResponse{}, c, "/series/release", params)
}

func (h *FREDHandler) SearchSeries(c *gin.Context) {
	searchText := c.Query("search_text")
	if searchText == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "search_text is required",
		})
		return
	}
	params := map[string]string{"search_text": searchText}
	h.addOptionalParams(c, params, []string{
		"realtime_start", "realtime_end", "limit", "offset", "sort_order",
		"order_by", "filter", "" +
			"" +
			"" +
			"" +
			"" +
			"",
	})
	h.fetchData(&models.SearchResponse{}, c, "/series/search", params)
}

func (h *FREDHandler) SearchSeriesTags(c *gin.Context) {
	searchText := c.Query("search_text")
	if searchText == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "search_text is required",
		})
		return
	}
	params := map[string]string{"search_text": searchText}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order"})
	h.fetchData(&models.TagsResponse{}, c, "/series/search/tags", params)
}

func (h *FREDHandler) SearchSeriesRelatedTags(c *gin.Context) {
	searchText := c.Query("search_text")
	if searchText == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "search_text is required",
		})
		return
	}
	tagNames := c.Query("tag_names")
	if tagNames == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "tag_names is required",
		})
		return
	}
	params := map[string]string{"search_text": searchText, "tag_names": tagNames}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order"})
	h.fetchData(&models.RelatedTagsResponse{}, c, "/series/search/related_tags", params)
}

func (h *FREDHandler) GetSeriesTags(c *gin.Context) {
	seriesID := c.Query("series_id")
	if seriesID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "series_id is required",
		})
		return
	}
	params := map[string]string{"series_id": seriesID}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order"})
	h.fetchData(&models.SeriesTagsResponse{}, c, "/series/tags", params)
}

func (h *FREDHandler) GetSeriesUpdates(c *gin.Context) {
	params := map[string]string{}
	h.addOptionalParams(c, params, []string{
		"realtime_start", "realtime_end", "limit", "offset", "sort_order",
		"filter", "observation_start", "observation_end",
	})
	h.fetchData(&models.SeriesUpdatesResponse{}, c, "/series/updates", params)
}

func (h *FREDHandler) GetSeriesVintageDates(c *gin.Context) {
	seriesID := c.Query("series_id")
	if seriesID == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "series_id is required",
		})
		return
	}
	params := map[string]string{"series_id": seriesID}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end"})
	h.fetchData(&models.VintageDatesResponse{}, c, "/series/vintagedates", params)
}

func (h *FREDHandler) GetReleases(c *gin.Context) {
	params := map[string]string{}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "sort_order"})
	h.fetchData(&models.ReleasesResponse{}, c, "/releases", params)
}

func (h *FREDHandler) GetReleaseDates(c *gin.Context) {
	params := map[string]string{}
	h.addOptionalParams(c, params, []string{
		"realtime_start", "realtime_end", "limit", "offset", "sort_order",
		"release_id", "date", "start_date", "end_date",
	})
	h.fetchData(&models.ReleaseDatesResponse{}, c, "/releases/dates", params)
}

func (h *FREDHandler) GetRelease(c *gin.Context) {
	releaseIDStr := c.Query("release_id")
	if releaseIDStr == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "release_id is required",
		})
		return
	}
	releaseID, _ := strconv.Atoi(releaseIDStr)
	params := map[string]string{"release_id": strconv.Itoa(releaseID)}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end"})
	h.fetchData(&models.ReleaseResponse{}, c, "/release", params)
}

func (h *FREDHandler) GetReleaseDates2(c *gin.Context) {
	releaseIDStr := c.Query("release_id")
	if releaseIDStr == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "release_id is required",
		})
		return
	}
	releaseID, _ := strconv.Atoi(releaseIDStr)
	params := map[string]string{"release_id": strconv.Itoa(releaseID)}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "sort_order", "date", "start_date", "end_date"})
	h.fetchData(&models.ReleaseDatesResponse{}, c, "/release/dates", params)
}

func (h *FREDHandler) GetReleaseSeries(c *gin.Context) {
	releaseIDStr := c.Query("release_id")
	if releaseIDStr == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "release_id is required",
		})
		return
	}
	releaseID, _ := strconv.Atoi(releaseIDStr)
	params := map[string]string{"release_id": strconv.Itoa(releaseID)}
	h.addOptionalParams(c, params, []string{
		"realtime_start", "realtime_end", "limit", "offset", "sort_order",
		"order_by", "filter", "observation_start", "observation_end", "units", "frequency",
		"aggregation_method", "output_type",
	})
	h.fetchData(&models.SearchResponse{}, c, "/release/series", params)
}

func (h *FREDHandler) GetReleaseSources(c *gin.Context) {
	releaseIDStr := c.Query("release_id")
	if releaseIDStr == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "release_id is required",
		})
		return
	}
	releaseID, _ := strconv.Atoi(releaseIDStr)
	params := map[string]string{"release_id": strconv.Itoa(releaseID)}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end"})
	h.fetchData(&models.ReleaseSourcesResponse{}, c, "/release/sources", params)
}

func (h *FREDHandler) GetReleaseTags(c *gin.Context) {
	releaseIDStr := c.Query("release_id")
	if releaseIDStr == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "release_id is required",
		})
		return
	}
	releaseID, _ := strconv.Atoi(releaseIDStr)
	params := map[string]string{"release_id": strconv.Itoa(releaseID)}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order"})
	h.fetchData(&models.ReleaseTagsResponse{}, c, "/release/tags", params)
}

func (h *FREDHandler) GetReleaseRelatedTags(c *gin.Context) {
	releaseIDStr := c.Query("release_id")
	if releaseIDStr == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "release_id is required",
		})
		return
	}
	tagNames := c.Query("tag_names")
	if tagNames == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "tag_names is required",
		})
		return
	}
	releaseID, _ := strconv.Atoi(releaseIDStr)
	params := map[string]string{"release_id": strconv.Itoa(releaseID), "tag_names": tagNames}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order"})
	h.fetchData(&models.RelatedTagsResponse{}, c, "/release/related_tags", params)
}

func (h *FREDHandler) GetReleaseTables(c *gin.Context) {
	releaseIDStr := c.Query("release_id")
	if releaseIDStr == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "release_id is required",
		})
		return
	}
	releaseID, _ := strconv.Atoi(releaseIDStr)
	params := map[string]string{"release_id": strconv.Itoa(releaseID)}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end"})
	h.fetchData(&models.ReleaseTablesResponse{}, c, "/release/tables", params)
}

func (h *FREDHandler) GetSources(c *gin.Context) {
	params := map[string]string{}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "sort_order"})
	h.fetchData(&models.SourcesResponse{}, c, "/sources", params)
}

func (h *FREDHandler) GetSource(c *gin.Context) {
	sourceIDStr := c.Query("source_id")
	if sourceIDStr == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "source_id is required",
		})
		return
	}
	sourceID, _ := strconv.Atoi(sourceIDStr)
	params := map[string]string{"source_id": strconv.Itoa(sourceID)}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end"})
	h.fetchData(&models.SourceResponse{}, c, "/source", params)
}

func (h *FREDHandler) GetSourceReleases(c *gin.Context) {
	sourceIDStr := c.Query("source_id")
	if sourceIDStr == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "source_id is required",
		})
		return
	}
	sourceID, _ := strconv.Atoi(sourceIDStr)
	params := map[string]string{"source_id": strconv.Itoa(sourceID)}
	h.addOptionalParams(c, params, []string{"realtime_start", "realtime_end", "limit", "offset", "sort_order"})
	h.fetchData(&models.ReleasesResponse{}, c, "/source/releases", params)
}

func (h *FREDHandler) GetTags(c *gin.Context) {
	params := map[string]string{}
	h.addOptionalParams(c, params, []string{
		"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order",
		"tag_name", "tag_group_id", "filter",
	})
	h.fetchData(&models.TagsResponse{}, c, "/tags", params)
}

func (h *FREDHandler) GetRelatedTags(c *gin.Context) {
	tagNames := c.Query("tag_names")
	if tagNames == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "tag_names is required",
		})
		return
	}
	params := map[string]string{"tag_names": tagNames}
	h.addOptionalParams(c, params, []string{
		"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order",
	})
	h.fetchData(&models.RelatedTagsResponse{}, c, "/related_tags", params)
}

func (h *FREDHandler) GetTagsSeries(c *gin.Context) {
	tagNames := c.Query("tag_names")
	if tagNames == "" {
		c.JSON(http.StatusBadRequest, models.ErrorResponse{
			ErrorCode:    "BadRequest",
			ErrorMessage: "tag_names is required",
		})
		return
	}
	params := map[string]string{"tag_names": tagNames}
	h.addOptionalParams(c, params, []string{
		"realtime_start", "realtime_end", "limit", "offset", "order_by", "sort_order",
		"filter", "" +
			"" +
			"" +
			"" +
			"" +
			"",
	})
	h.fetchData(&models.SearchResponse{}, c, "/tags/series", params)
}

func (h *FREDHandler) addOptionalParams(c *gin.Context, params map[string]string, optionals []string) {
	for _, param := range optionals {
		if v := c.Query(param); v != "" {
			params[param] = strings.TrimSpace(v)
		}
	}
}