/***

  Oak - Non-Linear Video Editor
  Copyright (C) 2026 Oak Team

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.

***/

// Pure C ABI test for the liboakengine preview facade: clip loop mode,
// per-channel audio levels (one-frame RMS) and footage waveform summary.
// Audio renders through RenderManager's audio thread and needs no GL
// (only the RENDER init bit). Uses the real media file tests/demo.mp4.

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#if defined(_WIN32)
#include <direct.h>
#include <windows.h>
#else
#include <unistd.h>
#endif

#include "oakengine/footage.h"
#include "oakengine/init.h"
#include "oakengine/preview.h"
#include "oakengine/project.h"
#include "oakengine/timeline.h"

#ifndef OAK_TEST_SOURCE_DIR
#define OAK_TEST_SOURCE_DIR "."
#endif

static char g_tmpdir[4096];

static void make_tmpdir(void)
{
#if defined(_WIN32)
	char base[MAX_PATH];
	const DWORD len = GetTempPathA(MAX_PATH, base);
	assert(len > 0 && len < MAX_PATH);
	snprintf(g_tmpdir, sizeof(g_tmpdir), "%soakengine_preview_test_%lu",
			 base, (unsigned long)GetCurrentProcessId());
	assert(_mkdir(g_tmpdir) == 0);
#else
	strcpy(g_tmpdir, "/tmp/oakengine_preview_test_XXXXXX");
	assert(mkdtemp(g_tmpdir) != NULL);
#endif
}

static void demo_path(char *dst, size_t cap)
{
	const int n = snprintf(dst, cap, "%s/tests/demo.mp4", OAK_TEST_SOURCE_DIR);
	assert(n > 0 && (size_t)n < cap);
}

static void test_loop_mode(OakEngineProject *project, OakEngineClip *clip)
{
	assert(oakengine_clip_get_loop_mode(clip) == OAKENGINE_LOOP_MODE_OFF);

	assert(oakengine_clip_set_loop_mode(clip, OAKENGINE_LOOP_MODE_LOOP) ==
		   OAKENGINE_OK);
	assert(oakengine_clip_get_loop_mode(clip) == OAKENGINE_LOOP_MODE_LOOP);
	assert(oakengine_clip_set_loop_mode(clip, OAKENGINE_LOOP_MODE_CLAMP) ==
		   OAKENGINE_OK);
	assert(oakengine_clip_get_loop_mode(clip) == OAKENGINE_LOOP_MODE_CLAMP);

	// Unknown modes and NULL are rejected.
	assert(oakengine_clip_set_loop_mode(clip, 3) == OAKENGINE_E_INVALID);
	assert(oakengine_clip_set_loop_mode(clip, -1) == OAKENGINE_E_INVALID);
	assert(oakengine_clip_set_loop_mode(NULL, 0) == OAKENGINE_E_INVALID);
	assert(oakengine_clip_get_loop_mode(NULL) == OAKENGINE_E_INVALID);

	// Undoable: undo restores LOOP then OFF, redo restores LOOP then CLAMP.
	assert(oakengine_project_undo(project) == OAKENGINE_OK);
	assert(oakengine_clip_get_loop_mode(clip) == OAKENGINE_LOOP_MODE_LOOP);
	assert(oakengine_project_undo(project) == OAKENGINE_OK);
	assert(oakengine_clip_get_loop_mode(clip) == OAKENGINE_LOOP_MODE_OFF);
	assert(oakengine_project_redo(project) == OAKENGINE_OK);
	assert(oakengine_project_redo(project) == OAKENGINE_OK);
	assert(oakengine_clip_get_loop_mode(clip) == OAKENGINE_LOOP_MODE_CLAMP);
}

// Generate a loud test tone (440 Hz stereo sine, 2 s) with the ffmpeg
// CLI -- the demo file's own audio track is essentially silent
// (volumedetect: -91 dB), so a real tone is needed to exercise the
// "content present" assertions. Requires ffmpeg in PATH, like the proxy
// tests do.
static void make_tone(char *dst, size_t cap)
{
	const int n = snprintf(dst, cap, "%s/tone.wav", g_tmpdir);
	assert(n > 0 && (size_t)n < cap);
	char cmd[4608];
	snprintf(cmd, sizeof(cmd),
			 "ffmpeg -v error -y -f lavfi -i "
			 "\"sine=frequency=440:duration=2\" -ar 48000 -ac 2 \"%s\"",
			 dst);
	assert(system(cmd) == 0);
	FILE *f = fopen(dst, "rb");
	assert(f != NULL);
	fclose(f);
}

static void test_levels(OakEngineSequence *seq)
{
	char err[256];
	double levels[4] = { -1.0, -1.0, -1.0, -1.0 };

	// Inside the clip (30 frames at 30000/1001): a loud sine on both
	// channels. RMS of a full-scale sine is ~0.707.
	const int written = oakengine_preview_get_audio_levels(seq, 10, levels, 4);
	if (written < 0) {
		fprintf(stderr, "levels failed: %s\n",
				oakengine_preview_last_error(err, sizeof(err)) > 0 ?
					err :
					"(no error)");
	}
	assert(written == 2);
	assert(levels[2] == 0.0 && levels[3] == 0.0); // beyond channel count

	// Past the end of the track: exact silence (the buffer may still be
	// allocated; the values are what matter).
	double silent[2] = { -1.0, -1.0 };
	assert(oakengine_preview_get_audio_levels(seq, 35, silent, 2) >= 0);
	assert(silent[0] == 0.0 && silent[1] == 0.0);

	// Error paths.
	assert(oakengine_preview_get_audio_levels(NULL, 10, levels, 2) ==
		   OAKENGINE_E_INVALID);
	assert(oakengine_preview_get_audio_levels(seq, -1, levels, 2) ==
		   OAKENGINE_E_INVALID);
	assert(oakengine_preview_get_audio_levels(seq, 10, NULL, 2) ==
		   OAKENGINE_E_INVALID);
	assert(oakengine_preview_get_audio_levels(seq, 10, levels, 0) ==
		   OAKENGINE_E_INVALID);
}

static void test_waveform(OakEngineFootage *tone, OakEngineFootage *demo,
						 OakEngineFootage *probed)
{
	double mins[16], maxs[16];

	// The tone in 10 buckets over one second: every bucket swings.
	assert(oakengine_preview_get_waveform_summary(tone, 0, 0, 30, mins,
												  maxs, 10) == OAKENGINE_OK);
	for (int i = 0; i < 10; i++) {
		assert(mins[i] <= maxs[i]);
		assert(mins[i] < 0.0 && maxs[i] > 0.0);
	}

	// The demo file's audio is essentially silent: tiny magnitudes.
	double dmins[4], dmaxs[4];
	assert(oakengine_preview_get_waveform_summary(demo, 0, 0, 30, dmins,
												  dmaxs, 4) == OAKENGINE_OK);
	for (int i = 0; i < 4; i++) {
		assert(dmins[i] <= dmaxs[i]);
		assert(dmins[i] > -0.01 && dmaxs[i] < 0.01);
	}

	// Far past the media: exact zeros.
	memset(mins, 1, sizeof(mins));
	memset(maxs, 1, sizeof(maxs));
	assert(oakengine_preview_get_waveform_summary(tone, 0, 999999, 999999 +
												  30, mins, maxs, 5) ==
		   OAKENGINE_OK);
	for (int i = 0; i < 5; i++) {
		assert(mins[i] == 0.0 && maxs[i] == 0.0);
	}

	// Error paths: probe handle, bad channel, bad count, NULL.
	assert(oakengine_preview_get_waveform_summary(probed, 0, 0, 30, mins,
												  maxs, 10) ==
		   OAKENGINE_E_INVALID);
	assert(oakengine_preview_get_waveform_summary(tone, 99, 0, 30, mins,
												  maxs, 10) ==
		   OAKENGINE_E_INVALID);
	assert(oakengine_preview_get_waveform_summary(tone, 0, 0, 30, mins,
												  maxs, 0) ==
		   OAKENGINE_E_INVALID);
	assert(oakengine_preview_get_waveform_summary(tone, 0, 30, 30, mins,
												  maxs, 10) ==
		   OAKENGINE_E_INVALID);
	assert(oakengine_preview_get_waveform_summary(NULL, 0, 0, 30, mins, maxs,
												  10) == OAKENGINE_E_INVALID);
	assert(oakengine_preview_get_waveform_summary(tone, 0, 0, 30, NULL,
												  maxs, 10) ==
		   OAKENGINE_E_INVALID);
}

int main(void)
{
	make_tmpdir();

	// Sandbox the config/cache/data locations (see oakengine_init_test).
#if !defined(_WIN32)
	assert(setenv("XDG_CONFIG_HOME", g_tmpdir, 1) == 0);
	assert(setenv("XDG_CACHE_HOME", g_tmpdir, 1) == 0);
	assert(setenv("XDG_DATA_HOME", g_tmpdir, 1) == 0);
#endif

	assert(oakengine_init(OAKENGINE_INIT_HEADLESS) == OAKENGINE_OK);

	OakEngineProject *project = oakengine_project_create();
	assert(project != NULL);
	assert(oakengine_project_new(project) == OAKENGINE_OK);
	OakEngineSequence *seq = oakengine_sequence_new(project, "Preview");
	assert(seq != NULL);

	char path[4096], tone_path[4096];
	demo_path(path, sizeof(path));
	make_tone(tone_path, sizeof(tone_path));
	// Levels render the tone clip on the sequence's audio track; the demo
	// file is used for the silent-content waveform case.
	OakEngineFootage *tone =
		oakengine_project_import_footage(project, tone_path);
	assert(tone != NULL);
	OakEngineFootage *demo =
		oakengine_project_import_footage(project, path);
	assert(demo != NULL);
	OakEngineFootage *probed = oakengine_footage_probe(path);
	assert(probed != NULL);

	// No RENDER bit yet: readouts fail with E_STATE.
	double levels[2];
	assert(oakengine_preview_get_audio_levels(seq, 0, levels, 2) ==
		   OAKENGINE_E_STATE);
	double mins[2], maxs[2];
	assert(oakengine_preview_get_waveform_summary(tone, 0, 0, 30, mins,
												  maxs, 2) ==
		   OAKENGINE_E_STATE);

	// Loop mode works headless already.
	OakEngineClip *clip = NULL;
	assert(oakengine_sequence_add_track(seq, OAKENGINE_TRACK_TYPE_VIDEO) ==
		   0);
	assert(oakengine_sequence_add_track(seq, OAKENGINE_TRACK_TYPE_AUDIO) ==
		   0);
	clip = oakengine_sequence_add_footage_clip(
		seq, demo, OAKENGINE_TRACK_TYPE_VIDEO, 0, 0, 30, 0);
	assert(clip != NULL);
	// The audio readouts need content on the audio track too.
	OakEngineClip *aclip = oakengine_sequence_add_footage_clip(
		seq, tone, OAKENGINE_TRACK_TYPE_AUDIO, 0, 0, 30, 0);
	assert(aclip != NULL);
	test_loop_mode(project, clip);

	// Upgrade to RENDER for the audio readouts (audio needs no GL).
	assert(oakengine_init(OAKENGINE_INIT_HEADLESS | OAKENGINE_INIT_RENDER) ==
		   OAKENGINE_OK);
	test_levels(seq);
	test_waveform(tone, demo, probed);

	oakengine_footage_free(probed);
	oakengine_footage_free(demo);
	oakengine_footage_free(tone);
	oakengine_project_free(project);
	assert(oakengine_shutdown() == OAKENGINE_OK);

	printf("oakengine_preview_test: all assertions passed\n");
	return 0;
}