/*
 * AlsaUseCase -- provide low level interface with ALSA lib (extracted from alsa-json-gateway code)
 * Copyright (C) 2015,2016,2017, Fulup Ar Foll fulup@iot.bzh
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.

   References:
      http://www.alsa-project.org/alsa-doc/alsa-lib/group__ucm.html
      https://www.alsa-project.org/main/index.php/DAPM
      http://alsa-lib.sourcearchive.com/documentation/1.0.24.1-2/group__Use_ga4332c6bb50481bbdaf21be11551fb930.html
      https://android.googlesource.com/platform/hardware/qcom/audio/+/jb-mr1-dev/libalsa-intf/alsa_ucm.h

   Sample alsaucm commands using /usr/share/alsa/ucm/PandaBoard
    - alsaucm  -c PandaBoard list _verbs
    - alsaucm  -c PandaBoard list _devices/HiFi
    - alsaucm  -c PandaBoard list _modifiers/HiFi  #need to uncomment modifiers section
    - alsaucm  -c PandaBoard list TQ/HiFi
    - alsaucm  -c PandaBoard get TQ/HiFi/Voice
    - alsaucm  -c PandaBoard get PlaybackPCM//HiFi
    - alsaucm  -c PandaBoard set _verb HiFi
    - alsaucm  -c PandaBoard set _verb HiFi _enadev Headset
    - alsaucm  -c 'HDA Intel PCH'  set _verb HiFi set  _enadev Headphone set _enamod RecordMedia
    - alsaucm  -c 'HDA Intel PCH'  set _verb HiFi get OutputDspName//

 */
#define _GNU_SOURCE  // needed for vasprintf

#include <alsa/asoundlib.h>
#include <alsa/asoundlib.h>
#include <alsa/use-case.h>

#include "Alsa-ApiHat.h"

typedef struct {
    snd_use_case_mgr_t *ucm;
    int cardId;
    char *cardName;
} ucmHandleT;

static ucmHandleT ucmHandles[MAX_SND_CARD];

// Cache opened UCM handles

STATIC int alsaUseCaseOpen(struct afb_req request, queryValuesT *queryValues, int allowNewMgr) {
    snd_ctl_t *ctlDev;
    snd_ctl_card_info_t *cardinfo;
    snd_use_case_mgr_t *ucmHandle;
    const char *cardName;
    int cardId, idx, idxFree = -1, err;

    // open control interface for devid
    err = snd_ctl_open(&ctlDev, queryValues->devid, SND_CTL_READONLY);
    if (err < 0) {
        ctlDev = NULL;
        afb_req_fail_f(request, "devid-unknown", "SndCard devid=[%s] Not Found err=%d", queryValues->devid, err);
        goto OnErrorExit;
    }

    snd_ctl_card_info_alloca(&cardinfo);
    if ((err = snd_ctl_card_info(ctlDev, cardinfo)) < 0) {
        afb_req_fail_f(request, "devid-invalid", "SndCard devid=[%s] Not Found err=%s", queryValues->devid, snd_strerror(err));
        goto OnErrorExit;
    }

    // search for an existing subscription and mark 1st free slot
    cardId = snd_ctl_card_info_get_card(cardinfo);
    for (idx = 0; idx < MAX_SND_CARD; idx++) {
        if (ucmHandles[idx].ucm != NULL) {
            if (ucmHandles[idx].cardId == cardId) goto OnSuccessExit;
        } else if (idxFree == -1) idxFree = idx;
    };

    if (!allowNewMgr) {
        afb_req_fail_f(request, "ucm-nomgr", "SndCard devid=[%s] no exiting UCM manager session", queryValues->devid);
        goto OnErrorExit;
    }

    if (idxFree < 0 && idx == MAX_SND_CARD) {
        afb_req_fail_f(request, "ucm-toomany", "SndCard devid=[%s] too many open UCM Max=%d", queryValues->devid, MAX_SND_CARD);
        goto OnErrorExit;
    }

    idx = idxFree;
    cardName = snd_ctl_card_info_get_name(cardinfo);
    err = snd_use_case_mgr_open(&ucmHandle, cardName);
    if (err) {
        afb_req_fail_f(request, "ucm-open", "SndCard devid=[%s] name=[%s] No UCM Profile err=%s", queryValues->devid, cardName, snd_strerror(err));
        goto OnErrorExit;
    }
    ucmHandles[idx].ucm = ucmHandle;
    ucmHandles[idx].cardId = cardId;
    ucmHandles[idx].cardName = strdup(cardName);

OnSuccessExit:
    if (ctlDev) snd_ctl_close(ctlDev);
    return idx;

OnErrorExit:
    if (ctlDev) snd_ctl_close(ctlDev);
    return -1;
}

PUBLIC void alsaUseCaseQuery(struct afb_req request) {
    int verbCount, ucmIdx;
    const char **verbList;
    snd_use_case_mgr_t *ucmHandle;
    queryValuesT queryValues;
    json_object *ucmJs;
    const char *cardName;

    json_object *queryJ = alsaCheckQuery(request, &queryValues);
    if (!queryJ) goto OnErrorExit;

    ucmIdx = alsaUseCaseOpen(request, &queryValues, TRUE);
    if (ucmIdx < 0) goto OnErrorExit;
    ucmHandle = ucmHandles [ucmIdx].ucm;
    cardName = ucmHandles [ucmIdx].cardName;

    verbCount = snd_use_case_get_list(ucmHandle, "_verbs", &verbList);
    if (verbCount < 0) {
        afb_req_fail_f(request, "ucm-list", "SndCard devid=[%s] name=[%s] No UCM Verbs", queryValues.devid, cardName);
        goto OnErrorExit;
    }

    ucmJs = json_object_new_array();
    for (int idx = 0; idx < verbCount; idx += 2) {
        int devCount, modCount, tqCount;
        const char **devList, **modList, **tqList;
        json_object *ucmJ = json_object_new_object();
        char identifier[32];

        json_object_object_add(ucmJ, "verb", json_object_new_string(verbList[idx]));
        if (verbList[idx + 1]) json_object_object_add(ucmJ, "info", json_object_new_string(verbList[idx + 1]));

        AFB_DEBUG("Verb[%d] Action=%s Info=%s", idx, verbList[idx], verbList[idx + 1]);

        snprintf(identifier, sizeof (identifier), "_devices/%s", verbList[idx]);
        devCount = snd_use_case_get_list(ucmHandle, identifier, &devList);
        if (devCount > 0) {
            json_object *devsJ = json_object_new_array();

            for (int jdx = 0; jdx < devCount; jdx += 2) {
                json_object *devJ = json_object_new_object();
                AFB_DEBUG("device[%d] Action=%s Info=%s", jdx, devList[jdx], devList[jdx + 1]);
                json_object_object_add(devJ, "dev", json_object_new_string(devList[jdx]));
                if (devList[jdx + 1]) json_object_object_add(devJ, "info", json_object_new_string(devList[jdx + 1]));
                json_object_array_add(devsJ, devJ);
            }
            json_object_object_add(ucmJ, "devices", devsJ);
            snd_use_case_free_list(devList, devCount);
        }

        snprintf(identifier, sizeof (identifier), "_modifiers/%s", verbList[idx]);
        modCount = snd_use_case_get_list(ucmHandle, identifier, &modList);
        if (modCount > 0) {
            json_object *modsJ = json_object_new_array();

            for (int jdx = 0; jdx < modCount; jdx += 2) {
                json_object *modJ = json_object_new_object();
                AFB_DEBUG("modifier[%d] Action=%s Info=%s", jdx, modList[jdx], modList[jdx + 1]);
                json_object_object_add(modJ, "mod", json_object_new_string(modList[jdx]));
                if (modList[jdx + 1]) json_object_object_add(modJ, "info", json_object_new_string(modList[jdx + 1]));
                json_object_array_add(modsJ, modJ);
            }
            json_object_object_add(ucmJ, "modifiers", modsJ);
            snd_use_case_free_list(modList, modCount);
        }

        snprintf(identifier, sizeof (identifier), "TQ/%s", verbList[idx]);
        tqCount = snd_use_case_get_list(ucmHandle, identifier, &tqList);
        if (tqCount > 0) {
            json_object *tqsJ = json_object_new_array();

            for (int jdx = 0; jdx < tqCount; jdx += 2) {
                json_object *tqJ = json_object_new_object();
                AFB_DEBUG("toneqa[%d] Action=%s Info=%s", jdx, tqList[jdx], tqList[jdx + 1]);
                json_object_object_add(tqJ, "tq", json_object_new_string(tqList[jdx]));
                if (tqList[jdx + 1]) json_object_object_add(tqJ, "info", json_object_new_string(tqList[jdx + 1]));
                json_object_array_add(tqsJ, tqJ);
            }
            json_object_object_add(ucmJ, "tqs", tqsJ);
            snd_use_case_free_list(tqList, tqCount);
        }

        json_object_array_add(ucmJs, ucmJ);
    }

    afb_req_success(request, ucmJs, NULL);
    snd_use_case_free_list(verbList, verbCount);

OnErrorExit:
    return;
}

STATIC json_object *ucmGetValue(ucmHandleT *ucmHandle, const char *verb, const char *mod, const char *label) {
    char identifier[80];
    char *value;
    int err;
    json_object *jValue;

    // handle optional parameters
    if (!mod) mod = "";
    if (!verb) verb = "";

    if (!label) {
        AFB_NOTICE("ucmGetValue cardname=[%s] value label missing", ucmHandle->cardName);
        goto OnErrorExit;
    }

    snprintf(identifier, sizeof (identifier), "%s/%s/%s", label, mod, verb);
    err = snd_use_case_get(ucmHandle->ucm, identifier, (const char**) &value); // Note: value casting is a known "FEATURE" of AlsaUCM API
    if (err) {
        AFB_DEBUG("ucmGetValue cardname=[%s] identifier=[%s] error=%s", ucmHandle->cardName, identifier, snd_strerror(err));
        goto OnErrorExit;
    }

    // copy value into json object and free string
    jValue = json_object_new_string(value);
    free(value);
    return (jValue);

OnErrorExit:
    return (NULL);
}

PUBLIC void alsaUseCaseGet(struct afb_req request) {
    int ucmIdx, labelCount;
    queryValuesT queryValues;
    json_object *jResponse = json_object_new_object();
    json_object *jWarnings = json_object_new_array();
    const char *warnings = NULL;

    json_object *queryJ = alsaCheckQuery(request, &queryValues);
    if (!queryJ) goto OnErrorExit;
    ;

    ucmIdx = alsaUseCaseOpen(request, &queryValues, TRUE);
    if (ucmIdx < 0) goto OnErrorExit;

    const char *cardName = ucmHandles[ucmIdx].cardName;

    const char *verb = afb_req_value(request, "verb");
    const char *mod = afb_req_value(request, "mod");
    const char *dev = afb_req_value(request, "dev");

    if (dev && mod) {
        afb_req_fail_f(request, "ucmget-labels", "SndCard devid=[%s] name=[%s] UCM mod+dev incompatible", queryValues.devid, cardName);
        goto OnErrorExit;
    }

    // device selection is handle as a modifier
    if (dev) mod = dev;

    const char *labels = afb_req_value(request, "value");
    if (!labels) {
        afb_req_fail_f(request, "ucmget-labels", "SndCard devid=[%s] name=[%s] UCM values name missing", queryValues.devid, cardName);
        goto OnErrorExit;
    }

    json_object *jLabels = json_tokener_parse(labels);
    if (!jLabels) {
        afb_req_fail_f(request, "ucmget-notjson", "labels=%s not a valid json entry", labels);
        goto OnErrorExit;
    };

    enum json_type jtype = json_object_get_type(jLabels);
    switch (jtype) {
            json_object *tmpJ;

        case json_type_array:
            labelCount = json_object_array_length(jLabels);
            break;

        case json_type_string:
            tmpJ = json_object_new_array();
            labelCount = 1;
            json_object_array_add(tmpJ, jLabels);
            jLabels = tmpJ;
            break;

        default:
            afb_req_fail_f(request, "ucmget-notarray", "labels=%s not valid JSON array", labels);
            goto OnErrorExit;
    }

    for (int idx = 0; idx < labelCount; idx++) {
        json_object *jValue, *jLabel;
        const char *label;

        jLabel = json_object_array_get_idx(jLabels, idx);
        label = json_object_get_string(jLabel);
        jValue = ucmGetValue(&ucmHandles[ucmIdx], verb, mod, label);
        if (jValue) json_object_object_add(jResponse, label, jValue);
        else {
            json_object_array_add(jWarnings, jLabel);
        }
    }

    // use info section to notified not found values label
    if (json_object_array_length(jWarnings) > 0) {
        json_object *tmpJ = json_object_new_object();
        json_object_object_add(tmpJ, "no-context", jWarnings);
        warnings = json_object_get_string(tmpJ);
    }
    afb_req_success(request, jResponse, warnings);

OnErrorExit:
    return;
}

PUBLIC void alsaUseCaseSet(struct afb_req request) {
    int err, ucmIdx;
    queryValuesT queryValues;
    json_object *jResponse = json_object_new_object();

    json_object *queryJ = alsaCheckQuery(request, &queryValues);
    if (!queryJ) goto OnErrorExit;


    ucmIdx = alsaUseCaseOpen(request, &queryValues, TRUE);
    if (ucmIdx < 0) goto OnErrorExit;

    snd_use_case_mgr_t *ucmMgr = ucmHandles[ucmIdx].ucm;
    const char *cardName = ucmHandles[ucmIdx].cardName;

    const char *verb = afb_req_value(request, "verb");
    const char *mod = afb_req_value(request, "mod");
    const char *dev = afb_req_value(request, "dev");
    // Known identifiers: _verb - set current verb = value _enadev - enable given device = value _disdev - disable given device = value _swdev/{old_device} - new_device = value

    if (verb) {
        err = snd_use_case_set(ucmMgr, "_verb", verb);
        if (err) {
            afb_req_fail_f(request, "ucmset-verb", "SndCard devid=[%s] name=[%s] Invalid UCM verb=[%s] err=%s", queryValues.devid, cardName, verb, snd_strerror(err));
            goto OnErrorExit;
        }
    }

    if (dev) {
        err = snd_use_case_set(ucmMgr, "_enadev", dev);
        if (err) {
            afb_req_fail_f(request, "ucmset-dev", "SndCard devid=[%s] name=[%s] Invalid UCMverb=[%s] dev=%s err=%s", queryValues.devid, cardName, verb, dev, snd_strerror(err));
            goto OnErrorExit;
        }
    }

    if (mod) {
        err = snd_use_case_set(ucmMgr, "_enamod", mod);
        if (err) {
            afb_req_fail_f(request, "ucmset-mod", "SndCard devid=[%s] name=[%s] Invalid UCM verb=[%s] mod=[%s] err=%s", queryValues.devid, cardName, verb, mod, snd_strerror(err));
            goto OnErrorExit;
        }
    }

    // label are requested transfert request to get
    if (afb_req_value(request, "value")) return alsaUseCaseGet(request);

    if (queryValues.mode <= 3) {
        json_object *jValue;

        jValue = ucmGetValue(&ucmHandles[ucmIdx], verb, dev, "OutputDspName");
        if (jValue) json_object_object_add(jResponse, "OutputDspName", jValue);

        jValue = ucmGetValue(&ucmHandles[ucmIdx], verb, dev, "PlaybackPCM");
        if (jValue) json_object_object_add(jResponse, "PlaybackPCM", jValue);

        jValue = ucmGetValue(&ucmHandles[ucmIdx], verb, mod, "CapturePCM");
        if (jValue) json_object_object_add(jResponse, "CapturePCM", jValue);
    }
    afb_req_success(request, jResponse, NULL);

OnErrorExit:
    return;
}

PUBLIC void alsaUseCaseReset(struct afb_req request) {
    int err, ucmIdx;
    queryValuesT queryValues;

    json_object *queryJ = alsaCheckQuery(request, &queryValues);
    if (!queryJ) goto OnErrorExit;

    ucmIdx = alsaUseCaseOpen(request, &queryValues, FALSE);
    if (ucmIdx < 0) goto OnErrorExit;

    err = snd_use_case_mgr_reset(ucmHandles[ucmIdx].ucm);
    if (err) {
        afb_req_fail_f(request, "ucmreset-fail", "devid=%s Card Name=%s", queryValues.devid, ucmHandles[ucmIdx].cardName);
        goto OnErrorExit;
    }

    afb_req_success(request, NULL, NULL);

OnErrorExit:
    return;
}

PUBLIC void alsaUseCaseClose(struct afb_req request) {
    int err, ucmIdx;
    queryValuesT queryValues;

    json_object *queryJ = alsaCheckQuery(request, &queryValues);
    if (!queryJ) goto OnErrorExit;

    ucmIdx = alsaUseCaseOpen(request, &queryValues, FALSE);
    if (ucmIdx < 0) goto OnErrorExit;

    err = snd_use_case_mgr_close(ucmHandles[ucmIdx].ucm);
    if (err) {
        afb_req_fail_f(request, "ucmreset-close", "devid=%s Card Name=%s", queryValues.devid, ucmHandles[ucmIdx].cardName);
        goto OnErrorExit;
    }

    // do not forget to release sound card name string
    free(ucmHandles[ucmIdx].cardName);

    afb_req_success(request, NULL, NULL);

OnErrorExit:
    return;
}