import os
import numpy as np
import sys
import hydra
from omegaconf import DictConfig, OmegaConf, ListConfig


def compute_wer(ref_file,
                hyp_file,
                cer_file,
                cn_postprocess=False,
                ):
	rst = {
		'Wrd': 0,
		'Corr': 0,
		'Ins': 0,
		'Del': 0,
		'Sub': 0,
		'Snt': 0,
		'Err': 0.0,
		'S.Err': 0.0,
		'wrong_words': 0,
		'wrong_sentences': 0
	}
	
	hyp_dict = {}
	ref_dict = {}
	with open(hyp_file, 'r') as hyp_reader:
		for line in hyp_reader:
			key = line.strip().split()[0]
			value = line.strip().split()[1:]
			if cn_postprocess:
				value = " ".join(value)
				value = value.replace(" ", "")
				if value[0] == "请":
					value = value[1:]
				value = [x for x in value]
			hyp_dict[key] = value
	with open(ref_file, 'r') as ref_reader:
		for line in ref_reader:
			key = line.strip().split()[0]
			value = line.strip().split()[1:]
			if cn_postprocess:
				value = " ".join(value)
				value = value.replace(" ", "")
				value = [x for x in value]
			ref_dict[key] = value
	
	cer_detail_writer = open(cer_file, 'w')
	for hyp_key in hyp_dict:
		if hyp_key in ref_dict:
			out_item = compute_wer_by_line(hyp_dict[hyp_key], ref_dict[hyp_key])
			rst['Wrd'] += out_item['nwords']
			rst['Corr'] += out_item['cor']
			rst['wrong_words'] += out_item['wrong']
			rst['Ins'] += out_item['ins']
			rst['Del'] += out_item['del']
			rst['Sub'] += out_item['sub']
			rst['Snt'] += 1
			if out_item['wrong'] > 0:
				rst['wrong_sentences'] += 1
			cer_detail_writer.write(hyp_key + print_cer_detail(out_item) + '\n')
			cer_detail_writer.write("ref:" + '\t' + " ".join(list(map(lambda x: x.lower(), ref_dict[hyp_key]))) + '\n')
			cer_detail_writer.write("hyp:" + '\t' + " ".join(list(map(lambda x: x.lower(), hyp_dict[hyp_key]))) + '\n')
			cer_detail_writer.flush()
	
	if rst['Wrd'] > 0:
		rst['Err'] = round(rst['wrong_words'] * 100 / rst['Wrd'], 2)
	if rst['Snt'] > 0:
		rst['S.Err'] = round(rst['wrong_sentences'] * 100 / rst['Snt'], 2)
	
	cer_detail_writer.write('\n')
	cer_detail_writer.write("%WER " + str(rst['Err']) + " [ " + str(rst['wrong_words']) + " / " + str(rst['Wrd']) +
	                        ", " + str(rst['Ins']) + " ins, " + str(rst['Del']) + " del, " + str(
		rst['Sub']) + " sub ]" + '\n')
	cer_detail_writer.write(
		"%SER " + str(rst['S.Err']) + " [ " + str(rst['wrong_sentences']) + " / " + str(rst['Snt']) + " ]" + '\n')
	cer_detail_writer.write("Scored " + str(len(hyp_dict)) + " sentences, " + str(
		len(hyp_dict) - rst['Snt']) + " not present in hyp." + '\n')
	
	cer_detail_writer.close()


def compute_wer_by_line(hyp,
                        ref):
	hyp = list(map(lambda x: x.lower(), hyp))
	ref = list(map(lambda x: x.lower(), ref))
	
	len_hyp = len(hyp)
	len_ref = len(ref)
	
	cost_matrix = np.zeros((len_hyp + 1, len_ref + 1), dtype=np.int16)
	
	ops_matrix = np.zeros((len_hyp + 1, len_ref + 1), dtype=np.int8)
	
	for i in range(len_hyp + 1):
		cost_matrix[i][0] = i
	for j in range(len_ref + 1):
		cost_matrix[0][j] = j
	
	for i in range(1, len_hyp + 1):
		for j in range(1, len_ref + 1):
			if hyp[i - 1] == ref[j - 1]:
				cost_matrix[i][j] = cost_matrix[i - 1][j - 1]
			else:
				substitution = cost_matrix[i - 1][j - 1] + 1
				insertion = cost_matrix[i - 1][j] + 1
				deletion = cost_matrix[i][j - 1] + 1
				
				compare_val = [substitution, insertion, deletion]
				
				min_val = min(compare_val)
				operation_idx = compare_val.index(min_val) + 1
				cost_matrix[i][j] = min_val
				ops_matrix[i][j] = operation_idx
	
	match_idx = []
	i = len_hyp
	j = len_ref
	rst = {
		'nwords': len_ref,
		'cor': 0,
		'wrong': 0,
		'ins': 0,
		'del': 0,
		'sub': 0
	}
	while i >= 0 or j >= 0:
		i_idx = max(0, i)
		j_idx = max(0, j)
		
		if ops_matrix[i_idx][j_idx] == 0:  # correct
			if i - 1 >= 0 and j - 1 >= 0:
				match_idx.append((j - 1, i - 1))
				rst['cor'] += 1
			
			i -= 1
			j -= 1
		
		elif ops_matrix[i_idx][j_idx] == 2:  # insert
			i -= 1
			rst['ins'] += 1
		
		elif ops_matrix[i_idx][j_idx] == 3:  # delete
			j -= 1
			rst['del'] += 1
		
		elif ops_matrix[i_idx][j_idx] == 1:  # substitute
			i -= 1
			j -= 1
			rst['sub'] += 1
		
		if i < 0 and j >= 0:
			rst['del'] += 1
		elif j < 0 and i >= 0:
			rst['ins'] += 1
	
	match_idx.reverse()
	wrong_cnt = cost_matrix[len_hyp][len_ref]
	rst['wrong'] = wrong_cnt
	
	return rst


def print_cer_detail(rst):
	return ("(" + "nwords=" + str(rst['nwords']) + ",cor=" + str(rst['cor'])
	        + ",ins=" + str(rst['ins']) + ",del=" + str(rst['del']) + ",sub="
	        + str(rst['sub']) + ") corr:" + '{:.2%}'.format(rst['cor'] / rst['nwords'])
	        + ",cer:" + '{:.2%}'.format(rst['wrong'] / rst['nwords']))


@hydra.main(config_name=None, version_base=None)
def main_hydra(cfg: DictConfig):
	ref_file = cfg.get("ref_file", None)
	hyp_file = cfg.get("hyp_file", None)
	cer_file = cfg.get("cer_file", None)
	cn_postprocess = cfg.get("cn_postprocess", False)
	if ref_file is None or hyp_file is None or cer_file is None:
		print(
			"usage : python -m  funasr.metrics.wer ++ref_file=test.ref ++hyp_file=test.hyp ++cer_file=test.wer ++cn_postprocess=false")
		sys.exit(0)
	
	compute_wer(ref_file, hyp_file, cer_file, cn_postprocess)


if __name__ == '__main__':
	main_hydra()