package api

import (
	"encoding/json"
	"errors"
	"io"
	"net/http"

	"github.com/go-chi/chi/v5"

	"git.fabledsword.com/bvandeusen/minstrel/internal/acquire"
	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
)

// Indexers and download clients, admin side (M502 #5518). Rows the operator
// adds and configures; nothing is seeded. Secrets are write-only: no response
// carries one, only whether it is set.

// acquisitionBodyLimit caps a settings body. The largest is a full form of
// short strings.
const acquisitionBodyLimit = 64 << 10

type acquisitionServiceResp struct {
	Code             string `json:"code"`
	Kind             string `json:"kind"`
	Protocol         string `json:"protocol"`
	Label            string `json:"label"`
	Enabled          bool   `json:"enabled"`
	BaseURL          string `json:"base_url"`
	HasAPIKey        bool   `json:"has_api_key"`
	HasPassword      bool   `json:"has_password"`
	Username         string `json:"username"`
	Category         string `json:"category"`
	TimeoutMs        int32  `json:"timeout_ms"`
	ServesSearch     bool   `json:"serves_search"`
	ServesDownloads  bool   `json:"serves_downloads"`
	ServesEnrichment bool   `json:"serves_enrichment"`
	LocalPath        string `json:"local_path"`
	RemotePath       string `json:"remote_path"`
	SearchesPerHour  int32  `json:"searches_per_hour"`
	// Usable is switched on and addressed: the state the jobs read.
	Usable bool `json:"usable"`
}

func acquisitionRespOf(r dbq.AcquisitionService) acquisitionServiceResp {
	return acquisitionServiceResp{
		Code: r.Code, Kind: r.Kind, Protocol: r.Protocol, Label: r.Label,
		Enabled: r.Enabled, BaseURL: r.BaseUrl,
		HasAPIKey: r.ApiKey != "", HasPassword: r.Password != "",
		Username: r.Username, Category: r.Category, TimeoutMs: r.TimeoutMs,
		ServesSearch: r.ServesSearch, ServesDownloads: r.ServesDownloads,
		ServesEnrichment: r.ServesEnrichment,
		LocalPath:        r.LocalPath, RemotePath: r.RemotePath,
		SearchesPerHour: r.SearchesPerHour,
		Usable:          r.Enabled && r.BaseUrl != "",
	}
}

// handleListAcquisitionServices implements GET /api/admin/acquisition/services.
func (h *handlers) handleListAcquisitionServices(w http.ResponseWriter, r *http.Request) {
	rows, err := h.acquisition.List(r.Context())
	if err != nil {
		writeErrWithLog(w, h.logger, "admin: list acquisition services", apierror.Internal(err))
		return
	}
	out := make([]acquisitionServiceResp, len(rows))
	for i, row := range rows {
		out[i] = acquisitionRespOf(dbq.AcquisitionService{
			Code: row.Code, Kind: row.Kind, Protocol: row.Protocol, Label: row.Label,
			Enabled: row.Enabled, BaseUrl: row.BaseUrl, Username: row.Username,
			Category: row.Category, TimeoutMs: row.TimeoutMs,
			ServesSearch: row.ServesSearch, ServesDownloads: row.ServesDownloads,
			ServesEnrichment: row.ServesEnrichment, LocalPath: row.LocalPath,
			RemotePath: row.RemotePath, SearchesPerHour: row.SearchesPerHour,
		})
		out[i].HasAPIKey, out[i].HasPassword = row.HasApiKey, row.HasPassword
	}
	writeJSON(w, http.StatusOK, map[string]any{"services": out})
}

// handleCreateAcquisitionService implements POST /api/admin/acquisition/services
// with {"protocol": "prowlarr"|"torznab"|"qbittorrent"|"exchange"}. The row
// starts switched off, with no address.
func (h *handlers) handleCreateAcquisitionService(w http.ResponseWriter, r *http.Request) {
	var body struct {
		Protocol string `json:"protocol"`
	}
	if !decodeAcquisitionBody(w, r, &body) {
		return
	}
	row, err := h.acquisition.Create(r.Context(), body.Protocol)
	if err != nil {
		h.writeAcquisitionErr(w, "admin: create acquisition service", err)
		return
	}
	writeJSON(w, http.StatusCreated, acquisitionRespOf(row))
}

type updateAcquisitionBody struct {
	Label            string `json:"label"`
	Enabled          bool   `json:"enabled"`
	BaseURL          string `json:"base_url"`
	Username         string `json:"username"`
	Category         string `json:"category"`
	TimeoutMs        int32  `json:"timeout_ms"`
	ServesSearch     bool   `json:"serves_search"`
	ServesDownloads  bool   `json:"serves_downloads"`
	ServesEnrichment bool   `json:"serves_enrichment"`
	LocalPath        string `json:"local_path"`
	RemotePath       string `json:"remote_path"`
	SearchesPerHour  int32  `json:"searches_per_hour"`
}

// handleUpdateAcquisitionService implements PUT
// /api/admin/acquisition/services/{code}: the whole form except credentials.
func (h *handlers) handleUpdateAcquisitionService(w http.ResponseWriter, r *http.Request) {
	var body updateAcquisitionBody
	if !decodeAcquisitionBody(w, r, &body) {
		return
	}
	row, err := h.acquisition.Save(r.Context(), chi.URLParam(r, "code"), acquire.Update(body))
	if err != nil {
		h.writeAcquisitionErr(w, "admin: update acquisition service", err)
		return
	}
	writeJSON(w, http.StatusOK, acquisitionRespOf(row))
}

// handleDeleteAcquisitionService implements DELETE
// /api/admin/acquisition/services/{code}.
func (h *handlers) handleDeleteAcquisitionService(w http.ResponseWriter, r *http.Request) {
	if err := h.acquisition.Delete(r.Context(), chi.URLParam(r, "code")); err != nil {
		h.writeAcquisitionErr(w, "admin: delete acquisition service", err)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// handleTestAcquisitionService implements POST
// /api/admin/acquisition/services/{code}/test. POST because it reaches
// another machine, which a prefetch must not trigger. Always 200 with
// {ok, detail}: a failed connection is the answer, not an error.
func (h *handlers) handleTestAcquisitionService(w http.ResponseWriter, r *http.Request) {
	row, err := h.acquisition.Get(r.Context(), chi.URLParam(r, "code"))
	if err != nil {
		h.writeAcquisitionErr(w, "admin: test acquisition service", err)
		return
	}
	writeJSON(w, http.StatusOK, acquire.Test(r.Context(), row))
}

// handleSetAcquisitionSecret implements PUT and DELETE on
// /api/admin/acquisition/services/{code}/api-key and .../password. PUT takes
// {"value": "..."}; DELETE clears it. 204 with no body either way: echoing
// anything here is how a secret ends up in a response.
func (h *handlers) handleSetAcquisitionSecret(field string) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		value := ""
		if r.Method == http.MethodPut {
			var body struct {
				Value string `json:"value"`
			}
			if !decodeAcquisitionBody(w, r, &body) {
				return
			}
			if body.Value == "" {
				writeErr(w, apierror.BadRequest("invalid_setting", "Paste a value, or use Remove to clear the one that is set."))
				return
			}
			value = body.Value
		}
		code := chi.URLParam(r, "code")
		var err error
		if field == "password" {
			err = h.acquisition.SetPassword(r.Context(), code, value)
		} else {
			err = h.acquisition.SetAPIKey(r.Context(), code, value)
		}
		if err != nil {
			h.writeAcquisitionErr(w, "admin: set acquisition "+field, err)
			return
		}
		w.WriteHeader(http.StatusNoContent)
	}
}

func decodeAcquisitionBody(w http.ResponseWriter, r *http.Request, into any) bool {
	err := json.NewDecoder(http.MaxBytesReader(w, r.Body, acquisitionBodyLimit)).Decode(into)
	if err != nil && !errors.Is(err, io.EOF) {
		writeErr(w, apierror.BadRequest("invalid_body", "malformed JSON"))
		return false
	}
	return true
}

func (h *handlers) writeAcquisitionErr(w http.ResponseWriter, msg string, err error) {
	var invalid *acquire.InvalidError
	switch {
	case errors.As(err, &invalid):
		writeErr(w, apierror.BadRequest("invalid_setting", invalid.Message))
	case errors.Is(err, acquire.ErrNotFound):
		writeErr(w, apierror.NotFound("service"))
	case errors.Is(err, acquire.ErrTooMany):
		writeErr(w, apierror.Conflict("too_many_services", "There are already twenty of these. Remove one you no longer use first."))
	default:
		writeErrWithLog(w, h.logger, msg, apierror.Internal(err))
	}
}